Merge remote-tracking branch 'airlied/drm-fixes' into drm-intel-next-queued

Back-merge from drm-fixes into drm-intel-next to sort out two things:

- interlaced support: -fixes contains a bugfix to correctly clear
  interlaced configuration bits in case the bios sets up an interlaced
  mode and we want to set up the progressive mode (current kernels
  don't support interlaced). The actual feature work to support
  interlaced depends upon (and conflicts with) this bugfix.

- forcewake voodoo to workaround missed IRQ issues: -fixes only enabled
  this for ivybridge, but some recent bug reports indicate that we
  need this on Sandybridge, too. But in a slightly different flavour
  and with other fixes and reworks on top. Additionally there are some
  forcewake cleanup patches heading to -next that would conflict with
  currrent -fixes.

Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

36 files changed, 6944 insertions, 1112 deletions

diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig
index ecb9fd3be14..d33f01c08b6 100644
--- a/fs/btrfs/Kconfig
+++ b/fs/btrfs/Kconfig
@@ -31,3 +31,22 @@ config BTRFS_FS_POSIX_ACL
 	  Linux website <http://acl.bestbits.at/>.
 
 	  If you don't know what Access Control Lists are, say N
+
+config BTRFS_FS_CHECK_INTEGRITY
+	bool "Btrfs with integrity check tool compiled in (DANGEROUS)"
+	depends on BTRFS_FS
+	help
+	  Adds code that examines all block write requests (including
+	  writes of the super block). The goal is to verify that the
+	  state of the filesystem on disk is always consistent, i.e.,
+	  after a power-loss or kernel panic event the filesystem is
+	  in a consistent state.
+
+	  If the integrity check tool is included and activated in
+	  the mount options, plenty of kernel memory is used, and
+	  plenty of additional CPU cycles are spent. Enabling this
+	  functionality is not intended for normal use.
+
+	  In most cases, unless you are a btrfs developer who needs
+	  to verify the integrity of (super)-block write requests
+	  during the run of a regression test, say N
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index c0ddfd29c5e..0c4fa2befae 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -8,6 +8,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
 	   extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \
 	   export.o tree-log.o free-space-cache.o zlib.o lzo.o \
 	   compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \
-	   reada.o backref.o
+	   reada.o backref.o ulist.o
 
 btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
+btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index cb97174e236..0cc20b35c1c 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -334,7 +334,7 @@ again:
 		if (freezing(current)) {
 			worker->working = 0;
 			spin_unlock_irq(&worker->lock);
-			refrigerator();
+			try_to_freeze();
 		} else {
 			spin_unlock_irq(&worker->lock);
 			if (!kthread_should_stop()) {
@@ -563,8 +563,8 @@ static struct btrfs_worker_thread *find_worker(struct btrfs_workers *workers)
 	struct list_head *fallback;
 	int ret;
 
-again:
 	spin_lock_irqsave(&workers->lock, flags);
+again:
 	worker = next_worker(workers);
 
 	if (!worker) {
@@ -579,6 +579,7 @@ again:
 			spin_unlock_irqrestore(&workers->lock, flags);
 			/* we're below the limit, start another worker */
 			ret = __btrfs_start_workers(workers);
+			spin_lock_irqsave(&workers->lock, flags);
 			if (ret)
 				goto fallback;
 			goto again;
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 22c64fff1bd..633c701a287 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -19,18 +19,789 @@
 #include "ctree.h"
 #include "disk-io.h"
 #include "backref.h"
+#include "ulist.h"
+#include "transaction.h"
+#include "delayed-ref.h"
 
-struct __data_ref {
+/*
+ * this structure records all encountered refs on the way up to the root
+ */
+struct __prelim_ref {
 	struct list_head list;
-	u64 inum;
-	u64 root;
-	u64 extent_data_item_offset;
+	u64 root_id;
+	struct btrfs_key key;
+	int level;
+	int count;
+	u64 parent;
+	u64 wanted_disk_byte;
 };
 
-struct __shared_ref {
-	struct list_head list;
+static int __add_prelim_ref(struct list_head *head, u64 root_id,
+			    struct btrfs_key *key, int level, u64 parent,
+			    u64 wanted_disk_byte, int count)
+{
+	struct __prelim_ref *ref;
+
+	/* in case we're adding delayed refs, we're holding the refs spinlock */
+	ref = kmalloc(sizeof(*ref), GFP_ATOMIC);
+	if (!ref)
+		return -ENOMEM;
+
+	ref->root_id = root_id;
+	if (key)
+		ref->key = *key;
+	else
+		memset(&ref->key, 0, sizeof(ref->key));
+
+	ref->level = level;
+	ref->count = count;
+	ref->parent = parent;
+	ref->wanted_disk_byte = wanted_disk_byte;
+	list_add_tail(&ref->list, head);
+
+	return 0;
+}
+
+static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
+				struct ulist *parents,
+				struct extent_buffer *eb, int level,
+				u64 wanted_objectid, u64 wanted_disk_byte)
+{
+	int ret;
+	int slot;
+	struct btrfs_file_extent_item *fi;
+	struct btrfs_key key;
 	u64 disk_byte;
-};
+
+add_parent:
+	ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
+	if (ret < 0)
+		return ret;
+
+	if (level != 0)
+		return 0;
+
+	/*
+	 * if the current leaf is full with EXTENT_DATA items, we must
+	 * check the next one if that holds a reference as well.
+	 * ref->count cannot be used to skip this check.
+	 * repeat this until we don't find any additional EXTENT_DATA items.
+	 */
+	while (1) {
+		ret = btrfs_next_leaf(root, path);
+		if (ret < 0)
+			return ret;
+		if (ret)
+			return 0;
+
+		eb = path->nodes[0];
+		for (slot = 0; slot < btrfs_header_nritems(eb); ++slot) {
+			btrfs_item_key_to_cpu(eb, &key, slot);
+			if (key.objectid != wanted_objectid ||
+			    key.type != BTRFS_EXTENT_DATA_KEY)
+				return 0;
+			fi = btrfs_item_ptr(eb, slot,
+						struct btrfs_file_extent_item);
+			disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
+			if (disk_byte == wanted_disk_byte)
+				goto add_parent;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * resolve an indirect backref in the form (root_id, key, level)
+ * to a logical address
+ */
+static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
+					struct __prelim_ref *ref,
+					struct ulist *parents)
+{
+	struct btrfs_path *path;
+	struct btrfs_root *root;
+	struct btrfs_key root_key;
+	struct btrfs_key key = {0};
+	struct extent_buffer *eb;
+	int ret = 0;
+	int root_level;
+	int level = ref->level;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	root_key.objectid = ref->root_id;
+	root_key.type = BTRFS_ROOT_ITEM_KEY;
+	root_key.offset = (u64)-1;
+	root = btrfs_read_fs_root_no_name(fs_info, &root_key);
+	if (IS_ERR(root)) {
+		ret = PTR_ERR(root);
+		goto out;
+	}
+
+	rcu_read_lock();
+	root_level = btrfs_header_level(root->node);
+	rcu_read_unlock();
+
+	if (root_level + 1 == level)
+		goto out;
+
+	path->lowest_level = level;
+	ret = btrfs_search_slot(NULL, root, &ref->key, path, 0, 0);
+	pr_debug("search slot in root %llu (level %d, ref count %d) returned "
+		 "%d for key (%llu %u %llu)\n",
+		 (unsigned long long)ref->root_id, level, ref->count, ret,
+		 (unsigned long long)ref->key.objectid, ref->key.type,
+		 (unsigned long long)ref->key.offset);
+	if (ret < 0)
+		goto out;
+
+	eb = path->nodes[level];
+	if (!eb) {
+		WARN_ON(1);
+		ret = 1;
+		goto out;
+	}
+
+	if (level == 0) {
+		if (ret == 1 && path->slots[0] >= btrfs_header_nritems(eb)) {
+			ret = btrfs_next_leaf(root, path);
+			if (ret)
+				goto out;
+			eb = path->nodes[0];
+		}
+
+		btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
+	}
+
+	/* the last two parameters will only be used for level == 0 */
+	ret = add_all_parents(root, path, parents, eb, level, key.objectid,
+				ref->wanted_disk_byte);
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
+/*
+ * resolve all indirect backrefs from the list
+ */
+static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
+				   struct list_head *head)
+{
+	int err;
+	int ret = 0;
+	struct __prelim_ref *ref;
+	struct __prelim_ref *ref_safe;
+	struct __prelim_ref *new_ref;
+	struct ulist *parents;
+	struct ulist_node *node;
+
+	parents = ulist_alloc(GFP_NOFS);
+	if (!parents)
+		return -ENOMEM;
+
+	/*
+	 * _safe allows us to insert directly after the current item without
+	 * iterating over the newly inserted items.
+	 * we're also allowed to re-assign ref during iteration.
+	 */
+	list_for_each_entry_safe(ref, ref_safe, head, list) {
+		if (ref->parent)	/* already direct */
+			continue;
+		if (ref->count == 0)
+			continue;
+		err = __resolve_indirect_ref(fs_info, ref, parents);
+		if (err) {
+			if (ret == 0)
+				ret = err;
+			continue;
+		}
+
+		/* we put the first parent into the ref at hand */
+		node = ulist_next(parents, NULL);
+		ref->parent = node ? node->val : 0;
+
+		/* additional parents require new refs being added here */
+		while ((node = ulist_next(parents, node))) {
+			new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS);
+			if (!new_ref) {
+				ret = -ENOMEM;
+				break;
+			}
+			memcpy(new_ref, ref, sizeof(*ref));
+			new_ref->parent = node->val;
+			list_add(&new_ref->list, &ref->list);
+		}
+		ulist_reinit(parents);
+	}
+
+	ulist_free(parents);
+	return ret;
+}
+
+/*
+ * merge two lists of backrefs and adjust counts accordingly
+ *
+ * mode = 1: merge identical keys, if key is set
+ * mode = 2: merge identical parents
+ */
+static int __merge_refs(struct list_head *head, int mode)
+{
+	struct list_head *pos1;
+
+	list_for_each(pos1, head) {
+		struct list_head *n2;
+		struct list_head *pos2;
+		struct __prelim_ref *ref1;
+
+		ref1 = list_entry(pos1, struct __prelim_ref, list);
+
+		if (mode == 1 && ref1->key.type == 0)
+			continue;
+		for (pos2 = pos1->next, n2 = pos2->next; pos2 != head;
+		     pos2 = n2, n2 = pos2->next) {
+			struct __prelim_ref *ref2;
+
+			ref2 = list_entry(pos2, struct __prelim_ref, list);
+
+			if (mode == 1) {
+				if (memcmp(&ref1->key, &ref2->key,
+					   sizeof(ref1->key)) ||
+				    ref1->level != ref2->level ||
+				    ref1->root_id != ref2->root_id)
+					continue;
+				ref1->count += ref2->count;
+			} else {
+				if (ref1->parent != ref2->parent)
+					continue;
+				ref1->count += ref2->count;
+			}
+			list_del(&ref2->list);
+			kfree(ref2);
+		}
+
+	}
+	return 0;
+}
+
+/*
+ * add all currently queued delayed refs from this head whose seq nr is
+ * smaller or equal that seq to the list
+ */
+static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
+			      struct btrfs_key *info_key,
+			      struct list_head *prefs)
+{
+	struct btrfs_delayed_extent_op *extent_op = head->extent_op;
+	struct rb_node *n = &head->node.rb_node;
+	int sgn;
+	int ret = 0;
+
+	if (extent_op && extent_op->update_key)
+		btrfs_disk_key_to_cpu(info_key, &extent_op->key);
+
+	while ((n = rb_prev(n))) {
+		struct btrfs_delayed_ref_node *node;
+		node = rb_entry(n, struct btrfs_delayed_ref_node,
+				rb_node);
+		if (node->bytenr != head->node.bytenr)
+			break;
+		WARN_ON(node->is_head);
+
+		if (node->seq > seq)
+			continue;
+
+		switch (node->action) {
+		case BTRFS_ADD_DELAYED_EXTENT:
+		case BTRFS_UPDATE_DELAYED_HEAD:
+			WARN_ON(1);
+			continue;
+		case BTRFS_ADD_DELAYED_REF:
+			sgn = 1;
+			break;
+		case BTRFS_DROP_DELAYED_REF:
+			sgn = -1;
+			break;
+		default:
+			BUG_ON(1);
+		}
+		switch (node->type) {
+		case BTRFS_TREE_BLOCK_REF_KEY: {
+			struct btrfs_delayed_tree_ref *ref;
+
+			ref = btrfs_delayed_node_to_tree_ref(node);
+			ret = __add_prelim_ref(prefs, ref->root, info_key,
+					       ref->level + 1, 0, node->bytenr,
+					       node->ref_mod * sgn);
+			break;
+		}
+		case BTRFS_SHARED_BLOCK_REF_KEY: {
+			struct btrfs_delayed_tree_ref *ref;
+
+			ref = btrfs_delayed_node_to_tree_ref(node);
+			ret = __add_prelim_ref(prefs, ref->root, info_key,
+					       ref->level + 1, ref->parent,
+					       node->bytenr,
+					       node->ref_mod * sgn);
+			break;
+		}
+		case BTRFS_EXTENT_DATA_REF_KEY: {
+			struct btrfs_delayed_data_ref *ref;
+			struct btrfs_key key;
+
+			ref = btrfs_delayed_node_to_data_ref(node);
+
+			key.objectid = ref->objectid;
+			key.type = BTRFS_EXTENT_DATA_KEY;
+			key.offset = ref->offset;
+			ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0,
+					       node->bytenr,
+					       node->ref_mod * sgn);
+			break;
+		}
+		case BTRFS_SHARED_DATA_REF_KEY: {
+			struct btrfs_delayed_data_ref *ref;
+			struct btrfs_key key;
+
+			ref = btrfs_delayed_node_to_data_ref(node);
+
+			key.objectid = ref->objectid;
+			key.type = BTRFS_EXTENT_DATA_KEY;
+			key.offset = ref->offset;
+			ret = __add_prelim_ref(prefs, ref->root, &key, 0,
+					       ref->parent, node->bytenr,
+					       node->ref_mod * sgn);
+			break;
+		}
+		default:
+			WARN_ON(1);
+		}
+		BUG_ON(ret);
+	}
+
+	return 0;
+}
+
+/*
+ * add all inline backrefs for bytenr to the list
+ */
+static int __add_inline_refs(struct btrfs_fs_info *fs_info,
+			     struct btrfs_path *path, u64 bytenr,
+			     struct btrfs_key *info_key, int *info_level,
+			     struct list_head *prefs)
+{
+	int ret = 0;
+	int slot;
+	struct extent_buffer *leaf;
+	struct btrfs_key key;
+	unsigned long ptr;
+	unsigned long end;
+	struct btrfs_extent_item *ei;
+	u64 flags;
+	u64 item_size;
+
+	/*
+	 * enumerate all inline refs
+	 */
+	leaf = path->nodes[0];
+	slot = path->slots[0] - 1;
+
+	item_size = btrfs_item_size_nr(leaf, slot);
+	BUG_ON(item_size < sizeof(*ei));
+
+	ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
+	flags = btrfs_extent_flags(leaf, ei);
+
+	ptr = (unsigned long)(ei + 1);
+	end = (unsigned long)ei + item_size;
+
+	if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
+		struct btrfs_tree_block_info *info;
+		struct btrfs_disk_key disk_key;
+
+		info = (struct btrfs_tree_block_info *)ptr;
+		*info_level = btrfs_tree_block_level(leaf, info);
+		btrfs_tree_block_key(leaf, info, &disk_key);
+		btrfs_disk_key_to_cpu(info_key, &disk_key);
+		ptr += sizeof(struct btrfs_tree_block_info);
+		BUG_ON(ptr > end);
+	} else {
+		BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
+	}
+
+	while (ptr < end) {
+		struct btrfs_extent_inline_ref *iref;
+		u64 offset;
+		int type;
+
+		iref = (struct btrfs_extent_inline_ref *)ptr;
+		type = btrfs_extent_inline_ref_type(leaf, iref);
+		offset = btrfs_extent_inline_ref_offset(leaf, iref);
+
+		switch (type) {
+		case BTRFS_SHARED_BLOCK_REF_KEY:
+			ret = __add_prelim_ref(prefs, 0, info_key,
+						*info_level + 1, offset,
+						bytenr, 1);
+			break;
+		case BTRFS_SHARED_DATA_REF_KEY: {
+			struct btrfs_shared_data_ref *sdref;
+			int count;
+
+			sdref = (struct btrfs_shared_data_ref *)(iref + 1);
+			count = btrfs_shared_data_ref_count(leaf, sdref);
+			ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
+					       bytenr, count);
+			break;
+		}
+		case BTRFS_TREE_BLOCK_REF_KEY:
+			ret = __add_prelim_ref(prefs, offset, info_key,
+					       *info_level + 1, 0, bytenr, 1);
+			break;
+		case BTRFS_EXTENT_DATA_REF_KEY: {
+			struct btrfs_extent_data_ref *dref;
+			int count;
+			u64 root;
+
+			dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+			count = btrfs_extent_data_ref_count(leaf, dref);
+			key.objectid = btrfs_extent_data_ref_objectid(leaf,
+								      dref);
+			key.type = BTRFS_EXTENT_DATA_KEY;
+			key.offset = btrfs_extent_data_ref_offset(leaf, dref);
+			root = btrfs_extent_data_ref_root(leaf, dref);
+			ret = __add_prelim_ref(prefs, root, &key, 0, 0, bytenr,
+						count);
+			break;
+		}
+		default:
+			WARN_ON(1);
+		}
+		BUG_ON(ret);
+		ptr += btrfs_extent_inline_ref_size(type);
+	}
+
+	return 0;
+}
+
+/*
+ * add all non-inline backrefs for bytenr to the list
+ */
+static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
+			    struct btrfs_path *path, u64 bytenr,
+			    struct btrfs_key *info_key, int info_level,
+			    struct list_head *prefs)
+{
+	struct btrfs_root *extent_root = fs_info->extent_root;
+	int ret;
+	int slot;
+	struct extent_buffer *leaf;
+	struct btrfs_key key;
+
+	while (1) {
+		ret = btrfs_next_item(extent_root, path);
+		if (ret < 0)
+			break;
+		if (ret) {
+			ret = 0;
+			break;
+		}
+
+		slot = path->slots[0];
+		leaf = path->nodes[0];
+		btrfs_item_key_to_cpu(leaf, &key, slot);
+
+		if (key.objectid != bytenr)
+			break;
+		if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
+			continue;
+		if (key.type > BTRFS_SHARED_DATA_REF_KEY)
+			break;
+
+		switch (key.type) {
+		case BTRFS_SHARED_BLOCK_REF_KEY:
+			ret = __add_prelim_ref(prefs, 0, info_key,
+						info_level + 1, key.offset,
+						bytenr, 1);
+			break;
+		case BTRFS_SHARED_DATA_REF_KEY: {
+			struct btrfs_shared_data_ref *sdref;
+			int count;
+
+			sdref = btrfs_item_ptr(leaf, slot,
+					      struct btrfs_shared_data_ref);
+			count = btrfs_shared_data_ref_count(leaf, sdref);
+			ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
+						bytenr, count);
+			break;
+		}
+		case BTRFS_TREE_BLOCK_REF_KEY:
+			ret = __add_prelim_ref(prefs, key.offset, info_key,
+						info_level + 1, 0, bytenr, 1);
+			break;
+		case BTRFS_EXTENT_DATA_REF_KEY: {
+			struct btrfs_extent_data_ref *dref;
+			int count;
+			u64 root;
+
+			dref = btrfs_item_ptr(leaf, slot,
+					      struct btrfs_extent_data_ref);
+			count = btrfs_extent_data_ref_count(leaf, dref);
+			key.objectid = btrfs_extent_data_ref_objectid(leaf,
+								      dref);
+			key.type = BTRFS_EXTENT_DATA_KEY;
+			key.offset = btrfs_extent_data_ref_offset(leaf, dref);
+			root = btrfs_extent_data_ref_root(leaf, dref);
+			ret = __add_prelim_ref(prefs, root, &key, 0, 0,
+						bytenr, count);
+			break;
+		}
+		default:
+			WARN_ON(1);
+		}
+		BUG_ON(ret);
+	}
+
+	return ret;
+}
+
+/*
+ * this adds all existing backrefs (inline backrefs, backrefs and delayed
+ * refs) for the given bytenr to the refs list, merges duplicates and resolves
+ * indirect refs to their parent bytenr.
+ * When roots are found, they're added to the roots list
+ *
+ * FIXME some caching might speed things up
+ */
+static int find_parent_nodes(struct btrfs_trans_handle *trans,
+			     struct btrfs_fs_info *fs_info, u64 bytenr,
+			     u64 seq, struct ulist *refs, struct ulist *roots)
+{
+	struct btrfs_key key;
+	struct btrfs_path *path;
+	struct btrfs_key info_key = { 0 };
+	struct btrfs_delayed_ref_root *delayed_refs = NULL;
+	struct btrfs_delayed_ref_head *head = NULL;
+	int info_level = 0;
+	int ret;
+	struct list_head prefs_delayed;
+	struct list_head prefs;
+	struct __prelim_ref *ref;
+
+	INIT_LIST_HEAD(&prefs);
+	INIT_LIST_HEAD(&prefs_delayed);
+
+	key.objectid = bytenr;
+	key.type = BTRFS_EXTENT_ITEM_KEY;
+	key.offset = (u64)-1;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	/*
+	 * grab both a lock on the path and a lock on the delayed ref head.
+	 * We need both to get a consistent picture of how the refs look
+	 * at a specified point in time
+	 */
+again:
+	ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
+	if (ret < 0)
+		goto out;
+	BUG_ON(ret == 0);
+
+	/*
+	 * look if there are updates for this ref queued and lock the head
+	 */
+	delayed_refs = &trans->transaction->delayed_refs;
+	spin_lock(&delayed_refs->lock);
+	head = btrfs_find_delayed_ref_head(trans, bytenr);
+	if (head) {
+		if (!mutex_trylock(&head->mutex)) {
+			atomic_inc(&head->node.refs);
+			spin_unlock(&delayed_refs->lock);
+
+			btrfs_release_path(path);
+
+			/*
+			 * Mutex was contended, block until it's
+			 * released and try again
+			 */
+			mutex_lock(&head->mutex);
+			mutex_unlock(&head->mutex);
+			btrfs_put_delayed_ref(&head->node);
+			goto again;
+		}
+		ret = __add_delayed_refs(head, seq, &info_key, &prefs_delayed);
+		if (ret)
+			goto out;
+	}
+	spin_unlock(&delayed_refs->lock);
+
+	if (path->slots[0]) {
+		struct extent_buffer *leaf;
+		int slot;
+
+		leaf = path->nodes[0];
+		slot = path->slots[0] - 1;
+		btrfs_item_key_to_cpu(leaf, &key, slot);
+		if (key.objectid == bytenr &&
+		    key.type == BTRFS_EXTENT_ITEM_KEY) {
+			ret = __add_inline_refs(fs_info, path, bytenr,
+						&info_key, &info_level, &prefs);
+			if (ret)
+				goto out;
+			ret = __add_keyed_refs(fs_info, path, bytenr, &info_key,
+					       info_level, &prefs);
+			if (ret)
+				goto out;
+		}
+	}
+	btrfs_release_path(path);
+
+	/*
+	 * when adding the delayed refs above, the info_key might not have
+	 * been known yet. Go over the list and replace the missing keys
+	 */
+	list_for_each_entry(ref, &prefs_delayed, list) {
+		if ((ref->key.offset | ref->key.type | ref->key.objectid) == 0)
+			memcpy(&ref->key, &info_key, sizeof(ref->key));
+	}
+	list_splice_init(&prefs_delayed, &prefs);
+
+	ret = __merge_refs(&prefs, 1);
+	if (ret)
+		goto out;
+
+	ret = __resolve_indirect_refs(fs_info, &prefs);
+	if (ret)
+		goto out;
+
+	ret = __merge_refs(&prefs, 2);
+	if (ret)
+		goto out;
+
+	while (!list_empty(&prefs)) {
+		ref = list_first_entry(&prefs, struct __prelim_ref, list);
+		list_del(&ref->list);
+		if (ref->count < 0)
+			WARN_ON(1);
+		if (ref->count && ref->root_id && ref->parent == 0) {
+			/* no parent == root of tree */
+			ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
+			BUG_ON(ret < 0);
+		}
+		if (ref->count && ref->parent) {
+			ret = ulist_add(refs, ref->parent, 0, GFP_NOFS);
+			BUG_ON(ret < 0);
+		}
+		kfree(ref);
+	}
+
+out:
+	if (head)
+		mutex_unlock(&head->mutex);
+	btrfs_free_path(path);
+	while (!list_empty(&prefs)) {
+		ref = list_first_entry(&prefs, struct __prelim_ref, list);
+		list_del(&ref->list);
+		kfree(ref);
+	}
+	while (!list_empty(&prefs_delayed)) {
+		ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
+				       list);
+		list_del(&ref->list);
+		kfree(ref);
+	}
+
+	return ret;
+}
+
+/*
+ * Finds all leafs with a reference to the specified combination of bytenr and
+ * offset. key_list_head will point to a list of corresponding keys (caller must
+ * free each list element). The leafs will be stored in the leafs ulist, which
+ * must be freed with ulist_free.
+ *
+ * returns 0 on success, <0 on error
+ */
+static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
+				struct btrfs_fs_info *fs_info, u64 bytenr,
+				u64 num_bytes, u64 seq, struct ulist **leafs)
+{
+	struct ulist *tmp;
+	int ret;
+
+	tmp = ulist_alloc(GFP_NOFS);
+	if (!tmp)
+		return -ENOMEM;
+	*leafs = ulist_alloc(GFP_NOFS);
+	if (!*leafs) {
+		ulist_free(tmp);
+		return -ENOMEM;
+	}
+
+	ret = find_parent_nodes(trans, fs_info, bytenr, seq, *leafs, tmp);
+	ulist_free(tmp);
+
+	if (ret < 0 && ret != -ENOENT) {
+		ulist_free(*leafs);
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * walk all backrefs for a given extent to find all roots that reference this
+ * extent. Walking a backref means finding all extents that reference this
+ * extent and in turn walk the backrefs of those, too. Naturally this is a
+ * recursive process, but here it is implemented in an iterative fashion: We
+ * find all referencing extents for the extent in question and put them on a
+ * list. In turn, we find all referencing extents for those, further appending
+ * to the list. The way we iterate the list allows adding more elements after
+ * the current while iterating. The process stops when we reach the end of the
+ * list. Found roots are added to the roots list.
+ *
+ * returns 0 on success, < 0 on error.
+ */
+int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
+				struct btrfs_fs_info *fs_info, u64 bytenr,
+				u64 num_bytes, u64 seq, struct ulist **roots)
+{
+	struct ulist *tmp;
+	struct ulist_node *node = NULL;
+	int ret;
+
+	tmp = ulist_alloc(GFP_NOFS);
+	if (!tmp)
+		return -ENOMEM;
+	*roots = ulist_alloc(GFP_NOFS);
+	if (!*roots) {
+		ulist_free(tmp);
+		return -ENOMEM;
+	}
+
+	while (1) {
+		ret = find_parent_nodes(trans, fs_info, bytenr, seq,
+					tmp, *roots);
+		if (ret < 0 && ret != -ENOENT) {
+			ulist_free(tmp);
+			ulist_free(*roots);
+			return ret;
+		}
+		node = ulist_next(tmp, node);
+		if (!node)
+			break;
+		bytenr = node->val;
+	}
+
+	ulist_free(tmp);
+	return 0;
+}
+
 
 static int __inode_info(u64 inum, u64 ioff, u8 key_type,
 			struct btrfs_root *fs_root, struct btrfs_path *path,
@@ -181,8 +952,11 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
 	btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
 	if (found_key->type != BTRFS_EXTENT_ITEM_KEY ||
 	    found_key->objectid > logical ||
-	    found_key->objectid + found_key->offset <= logical)
+	    found_key->objectid + found_key->offset <= logical) {
+		pr_debug("logical %llu is not within any extent\n",
+			 (unsigned long long)logical);
 		return -ENOENT;
+	}
 
 	eb = path->nodes[0];
 	item_size = btrfs_item_size_nr(eb, path->slots[0]);
@@ -191,6 +965,13 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
 	ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
 	flags = btrfs_extent_flags(eb, ei);
 
+	pr_debug("logical %llu is at position %llu within the extent (%llu "
+		 "EXTENT_ITEM %llu) flags %#llx size %u\n",
+		 (unsigned long long)logical,
+		 (unsigned long long)(logical - found_key->objectid),
+		 (unsigned long long)found_key->objectid,
+		 (unsigned long long)found_key->offset,
+		 (unsigned long long)flags, item_size);
 	if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
 		return BTRFS_EXTENT_FLAG_TREE_BLOCK;
 	if (flags & BTRFS_EXTENT_FLAG_DATA)
@@ -287,128 +1068,11 @@ int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
 	return 0;
 }
 
-static int __data_list_add(struct list_head *head, u64 inum,
-				u64 extent_data_item_offset, u64 root)
-{
-	struct __data_ref *ref;
-
-	ref = kmalloc(sizeof(*ref), GFP_NOFS);
-	if (!ref)
-		return -ENOMEM;
-
-	ref->inum = inum;
-	ref->extent_data_item_offset = extent_data_item_offset;
-	ref->root = root;
-	list_add_tail(&ref->list, head);
-
-	return 0;
-}
-
-static int __data_list_add_eb(struct list_head *head, struct extent_buffer *eb,
-				struct btrfs_extent_data_ref *dref)
-{
-	return __data_list_add(head, btrfs_extent_data_ref_objectid(eb, dref),
-				btrfs_extent_data_ref_offset(eb, dref),
-				btrfs_extent_data_ref_root(eb, dref));
-}
-
-static int __shared_list_add(struct list_head *head, u64 disk_byte)
-{
-	struct __shared_ref *ref;
-
-	ref = kmalloc(sizeof(*ref), GFP_NOFS);
-	if (!ref)
-		return -ENOMEM;
-
-	ref->disk_byte = disk_byte;
-	list_add_tail(&ref->list, head);
-
-	return 0;
-}
-
-static int __iter_shared_inline_ref_inodes(struct btrfs_fs_info *fs_info,
-					   u64 logical, u64 inum,
-					   u64 extent_data_item_offset,
-					   u64 extent_offset,
-					   struct btrfs_path *path,
-					   struct list_head *data_refs,
-					   iterate_extent_inodes_t *iterate,
-					   void *ctx)
-{
-	u64 ref_root;
-	u32 item_size;
-	struct btrfs_key key;
-	struct extent_buffer *eb;
-	struct btrfs_extent_item *ei;
-	struct btrfs_extent_inline_ref *eiref;
-	struct __data_ref *ref;
-	int ret;
-	int type;
-	int last;
-	unsigned long ptr = 0;
-
-	WARN_ON(!list_empty(data_refs));
-	ret = extent_from_logical(fs_info, logical, path, &key);
-	if (ret & BTRFS_EXTENT_FLAG_DATA)
-		ret = -EIO;
-	if (ret < 0)
-		goto out;
-
-	eb = path->nodes[0];
-	ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
-	item_size = btrfs_item_size_nr(eb, path->slots[0]);
-
-	ret = 0;
-	ref_root = 0;
-	/*
-	 * as done in iterate_extent_inodes, we first build a list of refs to
-	 * iterate, then free the path and then iterate them to avoid deadlocks.
-	 */
-	do {
-		last = __get_extent_inline_ref(&ptr, eb, ei, item_size,
-						&eiref, &type);
-		if (last < 0) {
-			ret = last;
-			goto out;
-		}
-		if (type == BTRFS_TREE_BLOCK_REF_KEY ||
-		    type == BTRFS_SHARED_BLOCK_REF_KEY) {
-			ref_root = btrfs_extent_inline_ref_offset(eb, eiref);
-			ret = __data_list_add(data_refs, inum,
-						extent_data_item_offset,
-						ref_root);
-		}
-	} while (!ret && !last);
-
-	btrfs_release_path(path);
-
-	if (ref_root == 0) {
-		printk(KERN_ERR "btrfs: failed to find tree block ref "
-			"for shared data backref %llu\n", logical);
-		WARN_ON(1);
-		ret = -EIO;
-	}
-
-out:
-	while (!list_empty(data_refs)) {
-		ref = list_first_entry(data_refs, struct __data_ref, list);
-		list_del(&ref->list);
-		if (!ret)
-			ret = iterate(ref->inum, extent_offset +
-					ref->extent_data_item_offset,
-					ref->root, ctx);
-		kfree(ref);
-	}
-
-	return ret;
-}
-
-static int __iter_shared_inline_ref(struct btrfs_fs_info *fs_info,
-				    u64 logical, u64 orig_extent_item_objectid,
-				    u64 extent_offset, struct btrfs_path *path,
-				    struct list_head *data_refs,
-				    iterate_extent_inodes_t *iterate,
-				    void *ctx)
+static int iterate_leaf_refs(struct btrfs_fs_info *fs_info,
+				struct btrfs_path *path, u64 logical,
+				u64 orig_extent_item_objectid,
+				u64 extent_item_pos, u64 root,
+				iterate_extent_inodes_t *iterate, void *ctx)
 {
 	u64 disk_byte;
 	struct btrfs_key key;
@@ -416,8 +1080,10 @@ static int __iter_shared_inline_ref(struct btrfs_fs_info *fs_info,
 	struct extent_buffer *eb;
 	int slot;
 	int nritems;
-	int ret;
-	int found = 0;
+	int ret = 0;
+	int extent_type;
+	u64 data_offset;
+	u64 data_len;
 
 	eb = read_tree_block(fs_info->tree_root, logical,
 				fs_info->tree_root->leafsize, 0);
@@ -435,149 +1101,99 @@ static int __iter_shared_inline_ref(struct btrfs_fs_info *fs_info,
 		if (key.type != BTRFS_EXTENT_DATA_KEY)
 			continue;
 		fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
-		if (!fi) {
-			free_extent_buffer(eb);
-			return -EIO;
-		}
+		extent_type = btrfs_file_extent_type(eb, fi);
+		if (extent_type == BTRFS_FILE_EXTENT_INLINE)
+			continue;
+		/* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
 		disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
-		if (disk_byte != orig_extent_item_objectid) {
-			if (found)
-				break;
-			else
-				continue;
-		}
-		++found;
-		ret = __iter_shared_inline_ref_inodes(fs_info, logical,
-							key.objectid,
-							key.offset,
-							extent_offset, path,
-							data_refs,
-							iterate, ctx);
-		if (ret)
-			break;
-	}
+		if (disk_byte != orig_extent_item_objectid)
+			continue;
 
-	if (!found) {
-		printk(KERN_ERR "btrfs: failed to follow shared data backref "
-			"to parent %llu\n", logical);
-		WARN_ON(1);
-		ret = -EIO;
+		data_offset = btrfs_file_extent_offset(eb, fi);
+		data_len = btrfs_file_extent_num_bytes(eb, fi);
+
+		if (extent_item_pos < data_offset ||
+		    extent_item_pos >= data_offset + data_len)
+			continue;
+
+		pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
+				"root %llu\n", orig_extent_item_objectid,
+				key.objectid, key.offset, root);
+		ret = iterate(key.objectid,
+				key.offset + (extent_item_pos - data_offset),
+				root, ctx);
+		if (ret) {
+			pr_debug("stopping iteration because ret=%d\n", ret);
+			break;
+		}
 	}
 
 	free_extent_buffer(eb);
+
 	return ret;
 }
 
 /*
  * calls iterate() for every inode that references the extent identified by
- * the given parameters. will use the path given as a parameter and return it
- * released.
+ * the given parameters.
  * when the iterator function returns a non-zero value, iteration stops.
+ * path is guaranteed to be in released state when iterate() is called.
  */
 int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
 				struct btrfs_path *path,
-				u64 extent_item_objectid,
-				u64 extent_offset,
+				u64 extent_item_objectid, u64 extent_item_pos,
 				iterate_extent_inodes_t *iterate, void *ctx)
 {
-	unsigned long ptr = 0;
-	int last;
 	int ret;
-	int type;
-	u64 logical;
-	u32 item_size;
-	struct btrfs_extent_inline_ref *eiref;
-	struct btrfs_extent_data_ref *dref;
-	struct extent_buffer *eb;
-	struct btrfs_extent_item *ei;
-	struct btrfs_key key;
 	struct list_head data_refs = LIST_HEAD_INIT(data_refs);
 	struct list_head shared_refs = LIST_HEAD_INIT(shared_refs);
-	struct __data_ref *ref_d;
-	struct __shared_ref *ref_s;
+	struct btrfs_trans_handle *trans;
+	struct ulist *refs;
+	struct ulist *roots;
+	struct ulist_node *ref_node = NULL;
+	struct ulist_node *root_node = NULL;
+	struct seq_list seq_elem;
+	struct btrfs_delayed_ref_root *delayed_refs;
+
+	trans = btrfs_join_transaction(fs_info->extent_root);
+	if (IS_ERR(trans))
+		return PTR_ERR(trans);
+
+	pr_debug("resolving all inodes for extent %llu\n",
+			extent_item_objectid);
+
+	delayed_refs = &trans->transaction->delayed_refs;
+	spin_lock(&delayed_refs->lock);
+	btrfs_get_delayed_seq(delayed_refs, &seq_elem);
+	spin_unlock(&delayed_refs->lock);
+
+	ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
+				   extent_item_pos, seq_elem.seq,
+				   &refs);
 
-	eb = path->nodes[0];
-	ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
-	item_size = btrfs_item_size_nr(eb, path->slots[0]);
-
-	/* first we iterate the inline refs, ... */
-	do {
-		last = __get_extent_inline_ref(&ptr, eb, ei, item_size,
-						&eiref, &type);
-		if (last == -ENOENT) {
-			ret = 0;
-			break;
-		}
-		if (last < 0) {
-			ret = last;
-			break;
-		}
-
-		if (type == BTRFS_EXTENT_DATA_REF_KEY) {
-			dref = (struct btrfs_extent_data_ref *)(&eiref->offset);
-			ret = __data_list_add_eb(&data_refs, eb, dref);
-		} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
-			logical = btrfs_extent_inline_ref_offset(eb, eiref);
-			ret = __shared_list_add(&shared_refs, logical);
-		}
-	} while (!ret && !last);
+	if (ret)
+		goto out;
 
-	/* ... then we proceed to in-tree references and ... */
-	while (!ret) {
-		++path->slots[0];
-		if (path->slots[0] > btrfs_header_nritems(eb)) {
-			ret = btrfs_next_leaf(fs_info->extent_root, path);
-			if (ret) {
-				if (ret == 1)
-					ret = 0; /* we're done */
-				break;
-			}
-			eb = path->nodes[0];
-		}
-		btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
-		if (key.objectid != extent_item_objectid)
+	while (!ret && (ref_node = ulist_next(refs, ref_node))) {
+		ret = btrfs_find_all_roots(trans, fs_info, ref_node->val, -1,
+						seq_elem.seq, &roots);
+		if (ret)
 			break;
-		if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
-			dref = btrfs_item_ptr(eb, path->slots[0],
-						struct btrfs_extent_data_ref);
-			ret = __data_list_add_eb(&data_refs, eb, dref);
-		} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
-			ret = __shared_list_add(&shared_refs, key.offset);
+		while (!ret && (root_node = ulist_next(roots, root_node))) {
+			pr_debug("root %llu references leaf %llu\n",
+					root_node->val, ref_node->val);
+			ret = iterate_leaf_refs(fs_info, path, ref_node->val,
+						extent_item_objectid,
+						extent_item_pos, root_node->val,
+						iterate, ctx);
 		}
 	}
 
-	btrfs_release_path(path);
-
-	/*
-	 * ... only at the very end we can process the refs we found. this is
-	 * because the iterator function we call is allowed to make tree lookups
-	 * and we have to avoid deadlocks. additionally, we need more tree
-	 * lookups ourselves for shared data refs.
-	 */
-	while (!list_empty(&data_refs)) {
-		ref_d = list_first_entry(&data_refs, struct __data_ref, list);
-		list_del(&ref_d->list);
-		if (!ret)
-			ret = iterate(ref_d->inum, extent_offset +
-					ref_d->extent_data_item_offset,
-					ref_d->root, ctx);
-		kfree(ref_d);
-	}
-
-	while (!list_empty(&shared_refs)) {
-		ref_s = list_first_entry(&shared_refs, struct __shared_ref,
-					list);
-		list_del(&ref_s->list);
-		if (!ret)
-			ret = __iter_shared_inline_ref(fs_info,
-							ref_s->disk_byte,
-							extent_item_objectid,
-							extent_offset, path,
-							&data_refs,
-							iterate, ctx);
-		kfree(ref_s);
-	}
-
+	ulist_free(refs);
+	ulist_free(roots);
+out:
+	btrfs_put_delayed_seq(delayed_refs, &seq_elem);
+	btrfs_end_transaction(trans, fs_info->extent_root);
 	return ret;
 }
 
@@ -586,19 +1202,20 @@ int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
 				iterate_extent_inodes_t *iterate, void *ctx)
 {
 	int ret;
-	u64 offset;
+	u64 extent_item_pos;
 	struct btrfs_key found_key;
 
 	ret = extent_from_logical(fs_info, logical, path,
 					&found_key);
+	btrfs_release_path(path);
 	if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK)
 		ret = -EINVAL;
 	if (ret < 0)
 		return ret;
 
-	offset = logical - found_key.objectid;
+	extent_item_pos = logical - found_key.objectid;
 	ret = iterate_extent_inodes(fs_info, path, found_key.objectid,
-					offset, iterate, ctx);
+					extent_item_pos, iterate, ctx);
 
 	return ret;
 }
@@ -643,6 +1260,10 @@ static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
 		for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
 			name_len = btrfs_inode_ref_name_len(eb, iref);
 			/* path must be released before calling iterate()! */
+			pr_debug("following ref at offset %u for inode %llu in "
+				 "tree %llu\n", cur,
+				 (unsigned long long)found_key.objectid,
+				 (unsigned long long)fs_root->objectid);
 			ret = iterate(parent, iref, eb, ctx);
 			if (ret) {
 				free_extent_buffer(eb);
@@ -683,10 +1304,14 @@ static int inode_to_path(u64 inum, struct btrfs_inode_ref *iref,
 		return PTR_ERR(fspath);
 
 	if (fspath > fspath_min) {
+		pr_debug("path resolved: %s\n", fspath);
 		ipath->fspath->val[i] = (u64)(unsigned long)fspath;
 		++ipath->fspath->elem_cnt;
 		ipath->fspath->bytes_left = fspath - fspath_min;
 	} else {
+		pr_debug("missed path, not enough space. missing bytes: %lu, "
+			 "constructed so far: %s\n",
+			 (unsigned long)(fspath_min - fspath), fspath_min);
 		++ipath->fspath->elem_missed;
 		ipath->fspath->bytes_missing += fspath_min - fspath;
 		ipath->fspath->bytes_left = 0;
diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index 92618837cb8..d00dfa9ca93 100644
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -20,6 +20,7 @@
 #define __BTRFS_BACKREF__
 
 #include "ioctl.h"
+#include "ulist.h"
 
 struct inode_fs_paths {
 	struct btrfs_path		*btrfs_path;
@@ -54,6 +55,10 @@ int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
 
 int paths_from_inode(u64 inum, struct inode_fs_paths *ipath);
 
+int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
+				struct btrfs_fs_info *fs_info, u64 bytenr,
+				u64 num_bytes, u64 seq, struct ulist **roots);
+
 struct btrfs_data_container *init_data_container(u32 total_bytes);
 struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
 					struct btrfs_path *path);
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 634608d2a6d..9b9b15fd520 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -51,6 +51,9 @@ struct btrfs_inode {
 	/* held while logging the inode in tree-log.c */
 	struct mutex log_mutex;
 
+	/* held while doing delalloc reservations */
+	struct mutex delalloc_mutex;
+
 	/* used to order data wrt metadata */
 	struct btrfs_ordered_inode_tree ordered_tree;
 
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
new file mode 100644
index 00000000000..b669a7d8e49
--- /dev/null
+++ b/fs/btrfs/check-integrity.c
@@ -0,0 +1,3069 @@
+/*
+ * Copyright (C) STRATO AG 2011.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+/*
+ * This module can be used to catch cases when the btrfs kernel
+ * code executes write requests to the disk that bring the file
+ * system in an inconsistent state. In such a state, a power-loss
+ * or kernel panic event would cause that the data on disk is
+ * lost or at least damaged.
+ *
+ * Code is added that examines all block write requests during
+ * runtime (including writes of the super block). Three rules
+ * are verified and an error is printed on violation of the
+ * rules:
+ * 1. It is not allowed to write a disk block which is
+ *    currently referenced by the super block (either directly
+ *    or indirectly).
+ * 2. When a super block is written, it is verified that all
+ *    referenced (directly or indirectly) blocks fulfill the
+ *    following requirements:
+ *    2a. All referenced blocks have either been present when
+ *        the file system was mounted, (i.e., they have been
+ *        referenced by the super block) or they have been
+ *        written since then and the write completion callback
+ *        was called and a FLUSH request to the device where
+ *        these blocks are located was received and completed.
+ *    2b. All referenced blocks need to have a generation
+ *        number which is equal to the parent's number.
+ *
+ * One issue that was found using this module was that the log
+ * tree on disk became temporarily corrupted because disk blocks
+ * that had been in use for the log tree had been freed and
+ * reused too early, while being referenced by the written super
+ * block.
+ *
+ * The search term in the kernel log that can be used to filter
+ * on the existence of detected integrity issues is
+ * "btrfs: attempt".
+ *
+ * The integrity check is enabled via mount options. These
+ * mount options are only supported if the integrity check
+ * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
+ *
+ * Example #1, apply integrity checks to all metadata:
+ * mount /dev/sdb1 /mnt -o check_int
+ *
+ * Example #2, apply integrity checks to all metadata and
+ * to data extents:
+ * mount /dev/sdb1 /mnt -o check_int_data
+ *
+ * Example #3, apply integrity checks to all metadata and dump
+ * the tree that the super block references to kernel messages
+ * each time after a super block was written:
+ * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
+ *
+ * If the integrity check tool is included and activated in
+ * the mount options, plenty of kernel memory is used, and
+ * plenty of additional CPU cycles are spent. Enabling this
+ * functionality is not intended for normal use. In most
+ * cases, unless you are a btrfs developer who needs to verify
+ * the integrity of (super)-block write requests, do not
+ * enable the config option BTRFS_FS_CHECK_INTEGRITY to
+ * include and compile the integrity check tool.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/buffer_head.h>
+#include <linux/mutex.h>
+#include <linux/crc32c.h>
+#include <linux/genhd.h>
+#include <linux/blkdev.h>
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "extent_io.h"
+#include "disk-io.h"
+#include "volumes.h"
+#include "print-tree.h"
+#include "locking.h"
+#include "check-integrity.h"
+
+#define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
+#define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
+#define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
+#define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
+#define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
+#define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
+#define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
+#define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)	/* in characters,
+							 * excluding " [...]" */
+#define BTRFSIC_BLOCK_SIZE PAGE_SIZE
+
+#define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
+
+/*
+ * The definition of the bitmask fields for the print_mask.
+ * They are specified with the mount option check_integrity_print_mask.
+ */
+#define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE			0x00000001
+#define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION		0x00000002
+#define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE			0x00000004
+#define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE			0x00000008
+#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH			0x00000010
+#define BTRFSIC_PRINT_MASK_END_IO_BIO_BH			0x00000020
+#define BTRFSIC_PRINT_MASK_VERBOSE				0x00000040
+#define BTRFSIC_PRINT_MASK_VERY_VERBOSE				0x00000080
+#define BTRFSIC_PRINT_MASK_INITIAL_TREE				0x00000100
+#define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES			0x00000200
+#define BTRFSIC_PRINT_MASK_INITIAL_DATABASE			0x00000400
+#define BTRFSIC_PRINT_MASK_NUM_COPIES				0x00000800
+#define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS		0x00001000
+
+struct btrfsic_dev_state;
+struct btrfsic_state;
+
+struct btrfsic_block {
+	u32 magic_num;		/* only used for debug purposes */
+	unsigned int is_metadata:1;	/* if it is meta-data, not data-data */
+	unsigned int is_superblock:1;	/* if it is one of the superblocks */
+	unsigned int is_iodone:1;	/* if is done by lower subsystem */
+	unsigned int iodone_w_error:1;	/* error was indicated to endio */
+	unsigned int never_written:1;	/* block was added because it was
+					 * referenced, not because it was
+					 * written */
+	unsigned int mirror_num:2;	/* large enough to hold
+					 * BTRFS_SUPER_MIRROR_MAX */
+	struct btrfsic_dev_state *dev_state;
+	u64 dev_bytenr;		/* key, physical byte num on disk */
+	u64 logical_bytenr;	/* logical byte num on disk */
+	u64 generation;
+	struct btrfs_disk_key disk_key;	/* extra info to print in case of
+					 * issues, will not always be correct */
+	struct list_head collision_resolving_node;	/* list node */
+	struct list_head all_blocks_node;	/* list node */
+
+	/* the following two lists contain block_link items */
+	struct list_head ref_to_list;	/* list */
+	struct list_head ref_from_list;	/* list */
+	struct btrfsic_block *next_in_same_bio;
+	void *orig_bio_bh_private;
+	union {
+		bio_end_io_t *bio;
+		bh_end_io_t *bh;
+	} orig_bio_bh_end_io;
+	int submit_bio_bh_rw;
+	u64 flush_gen; /* only valid if !never_written */
+};
+
+/*
+ * Elements of this type are allocated dynamically and required because
+ * each block object can refer to and can be ref from multiple blocks.
+ * The key to lookup them in the hashtable is the dev_bytenr of
+ * the block ref to plus the one from the block refered from.
+ * The fact that they are searchable via a hashtable and that a
+ * ref_cnt is maintained is not required for the btrfs integrity
+ * check algorithm itself, it is only used to make the output more
+ * beautiful in case that an error is detected (an error is defined
+ * as a write operation to a block while that block is still referenced).
+ */
+struct btrfsic_block_link {
+	u32 magic_num;		/* only used for debug purposes */
+	u32 ref_cnt;
+	struct list_head node_ref_to;	/* list node */
+	struct list_head node_ref_from;	/* list node */
+	struct list_head collision_resolving_node;	/* list node */
+	struct btrfsic_block *block_ref_to;
+	struct btrfsic_block *block_ref_from;
+	u64 parent_generation;
+};
+
+struct btrfsic_dev_state {
+	u32 magic_num;		/* only used for debug purposes */
+	struct block_device *bdev;
+	struct btrfsic_state *state;
+	struct list_head collision_resolving_node;	/* list node */
+	struct btrfsic_block dummy_block_for_bio_bh_flush;
+	u64 last_flush_gen;
+	char name[BDEVNAME_SIZE];
+};
+
+struct btrfsic_block_hashtable {
+	struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
+};
+
+struct btrfsic_block_link_hashtable {
+	struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
+};
+
+struct btrfsic_dev_state_hashtable {
+	struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
+};
+
+struct btrfsic_block_data_ctx {
+	u64 start;		/* virtual bytenr */
+	u64 dev_bytenr;		/* physical bytenr on device */
+	u32 len;
+	struct btrfsic_dev_state *dev;
+	char *data;
+	struct buffer_head *bh;	/* do not use if set to NULL */
+};
+
+/* This structure is used to implement recursion without occupying
+ * any stack space, refer to btrfsic_process_metablock() */
+struct btrfsic_stack_frame {
+	u32 magic;
+	u32 nr;
+	int error;
+	int i;
+	int limit_nesting;
+	int num_copies;
+	int mirror_num;
+	struct btrfsic_block *block;
+	struct btrfsic_block_data_ctx *block_ctx;
+	struct btrfsic_block *next_block;
+	struct btrfsic_block_data_ctx next_block_ctx;
+	struct btrfs_header *hdr;
+	struct btrfsic_stack_frame *prev;
+};
+
+/* Some state per mounted filesystem */
+struct btrfsic_state {
+	u32 print_mask;
+	int include_extent_data;
+	int csum_size;
+	struct list_head all_blocks_list;
+	struct btrfsic_block_hashtable block_hashtable;
+	struct btrfsic_block_link_hashtable block_link_hashtable;
+	struct btrfs_root *root;
+	u64 max_superblock_generation;
+	struct btrfsic_block *latest_superblock;
+};
+
+static void btrfsic_block_init(struct btrfsic_block *b);
+static struct btrfsic_block *btrfsic_block_alloc(void);
+static void btrfsic_block_free(struct btrfsic_block *b);
+static void btrfsic_block_link_init(struct btrfsic_block_link *n);
+static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
+static void btrfsic_block_link_free(struct btrfsic_block_link *n);
+static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
+static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
+static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
+static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
+static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
+					struct btrfsic_block_hashtable *h);
+static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
+static struct btrfsic_block *btrfsic_block_hashtable_lookup(
+		struct block_device *bdev,
+		u64 dev_bytenr,
+		struct btrfsic_block_hashtable *h);
+static void btrfsic_block_link_hashtable_init(
+		struct btrfsic_block_link_hashtable *h);
+static void btrfsic_block_link_hashtable_add(
+		struct btrfsic_block_link *l,
+		struct btrfsic_block_link_hashtable *h);
+static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
+static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
+		struct block_device *bdev_ref_to,
+		u64 dev_bytenr_ref_to,
+		struct block_device *bdev_ref_from,
+		u64 dev_bytenr_ref_from,
+		struct btrfsic_block_link_hashtable *h);
+static void btrfsic_dev_state_hashtable_init(
+		struct btrfsic_dev_state_hashtable *h);
+static void btrfsic_dev_state_hashtable_add(
+		struct btrfsic_dev_state *ds,
+		struct btrfsic_dev_state_hashtable *h);
+static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
+static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
+		struct block_device *bdev,
+		struct btrfsic_dev_state_hashtable *h);
+static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
+static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
+static int btrfsic_process_superblock(struct btrfsic_state *state,
+				      struct btrfs_fs_devices *fs_devices);
+static int btrfsic_process_metablock(struct btrfsic_state *state,
+				     struct btrfsic_block *block,
+				     struct btrfsic_block_data_ctx *block_ctx,
+				     struct btrfs_header *hdr,
+				     int limit_nesting, int force_iodone_flag);
+static int btrfsic_create_link_to_next_block(
+		struct btrfsic_state *state,
+		struct btrfsic_block *block,
+		struct btrfsic_block_data_ctx
+		*block_ctx, u64 next_bytenr,
+		int limit_nesting,
+		struct btrfsic_block_data_ctx *next_block_ctx,
+		struct btrfsic_block **next_blockp,
+		int force_iodone_flag,
+		int *num_copiesp, int *mirror_nump,
+		struct btrfs_disk_key *disk_key,
+		u64 parent_generation);
+static int btrfsic_handle_extent_data(struct btrfsic_state *state,
+				      struct btrfsic_block *block,
+				      struct btrfsic_block_data_ctx *block_ctx,
+				      u32 item_offset, int force_iodone_flag);
+static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
+			     struct btrfsic_block_data_ctx *block_ctx_out,
+			     int mirror_num);
+static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
+				  u32 len, struct block_device *bdev,
+				  struct btrfsic_block_data_ctx *block_ctx_out);
+static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
+static int btrfsic_read_block(struct btrfsic_state *state,
+			      struct btrfsic_block_data_ctx *block_ctx);
+static void btrfsic_dump_database(struct btrfsic_state *state);
+static int btrfsic_test_for_metadata(struct btrfsic_state *state,
+				     const u8 *data, unsigned int size);
+static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
+					  u64 dev_bytenr, u8 *mapped_data,
+					  unsigned int len, struct bio *bio,
+					  int *bio_is_patched,
+					  struct buffer_head *bh,
+					  int submit_bio_bh_rw);
+static int btrfsic_process_written_superblock(
+		struct btrfsic_state *state,
+		struct btrfsic_block *const block,
+		struct btrfs_super_block *const super_hdr);
+static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
+static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
+static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
+					      const struct btrfsic_block *block,
+					      int recursion_level);
+static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
+					struct btrfsic_block *const block,
+					int recursion_level);
+static void btrfsic_print_add_link(const struct btrfsic_state *state,
+				   const struct btrfsic_block_link *l);
+static void btrfsic_print_rem_link(const struct btrfsic_state *state,
+				   const struct btrfsic_block_link *l);
+static char btrfsic_get_block_type(const struct btrfsic_state *state,
+				   const struct btrfsic_block *block);
+static void btrfsic_dump_tree(const struct btrfsic_state *state);
+static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
+				  const struct btrfsic_block *block,
+				  int indent_level);
+static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
+		struct btrfsic_state *state,
+		struct btrfsic_block_data_ctx *next_block_ctx,
+		struct btrfsic_block *next_block,
+		struct btrfsic_block *from_block,
+		u64 parent_generation);
+static struct btrfsic_block *btrfsic_block_lookup_or_add(
+		struct btrfsic_state *state,
+		struct btrfsic_block_data_ctx *block_ctx,
+		const char *additional_string,
+		int is_metadata,
+		int is_iodone,
+		int never_written,
+		int mirror_num,
+		int *was_created);
+static int btrfsic_process_superblock_dev_mirror(
+		struct btrfsic_state *state,
+		struct btrfsic_dev_state *dev_state,
+		struct btrfs_device *device,
+		int superblock_mirror_num,
+		struct btrfsic_dev_state **selected_dev_state,
+		struct btrfs_super_block *selected_super);
+static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
+		struct block_device *bdev);
+static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
+					   u64 bytenr,
+					   struct btrfsic_dev_state *dev_state,
+					   u64 dev_bytenr, char *data);
+
+static struct mutex btrfsic_mutex;
+static int btrfsic_is_initialized;
+static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
+
+
+static void btrfsic_block_init(struct btrfsic_block *b)
+{
+	b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
+	b->dev_state = NULL;
+	b->dev_bytenr = 0;
+	b->logical_bytenr = 0;
+	b->generation = BTRFSIC_GENERATION_UNKNOWN;
+	b->disk_key.objectid = 0;
+	b->disk_key.type = 0;
+	b->disk_key.offset = 0;
+	b->is_metadata = 0;
+	b->is_superblock = 0;
+	b->is_iodone = 0;
+	b->iodone_w_error = 0;
+	b->never_written = 0;
+	b->mirror_num = 0;
+	b->next_in_same_bio = NULL;
+	b->orig_bio_bh_private = NULL;
+	b->orig_bio_bh_end_io.bio = NULL;
+	INIT_LIST_HEAD(&b->collision_resolving_node);
+	INIT_LIST_HEAD(&b->all_blocks_node);
+	INIT_LIST_HEAD(&b->ref_to_list);
+	INIT_LIST_HEAD(&b->ref_from_list);
+	b->submit_bio_bh_rw = 0;
+	b->flush_gen = 0;
+}
+
+static struct btrfsic_block *btrfsic_block_alloc(void)
+{
+	struct btrfsic_block *b;
+
+	b = kzalloc(sizeof(*b), GFP_NOFS);
+	if (NULL != b)
+		btrfsic_block_init(b);
+
+	return b;
+}
+
+static void btrfsic_block_free(struct btrfsic_block *b)
+{
+	BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
+	kfree(b);
+}
+
+static void btrfsic_block_link_init(struct btrfsic_block_link *l)
+{
+	l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
+	l->ref_cnt = 1;
+	INIT_LIST_HEAD(&l->node_ref_to);
+	INIT_LIST_HEAD(&l->node_ref_from);
+	INIT_LIST_HEAD(&l->collision_resolving_node);
+	l->block_ref_to = NULL;
+	l->block_ref_from = NULL;
+}
+
+static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
+{
+	struct btrfsic_block_link *l;
+
+	l = kzalloc(sizeof(*l), GFP_NOFS);
+	if (NULL != l)
+		btrfsic_block_link_init(l);
+
+	return l;
+}
+
+static void btrfsic_block_link_free(struct btrfsic_block_link *l)
+{
+	BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
+	kfree(l);
+}
+
+static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
+{
+	ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
+	ds->bdev = NULL;
+	ds->state = NULL;
+	ds->name[0] = '\0';
+	INIT_LIST_HEAD(&ds->collision_resolving_node);
+	ds->last_flush_gen = 0;
+	btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
+	ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
+	ds->dummy_block_for_bio_bh_flush.dev_state = ds;
+}
+
+static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
+{
+	struct btrfsic_dev_state *ds;
+
+	ds = kzalloc(sizeof(*ds), GFP_NOFS);
+	if (NULL != ds)
+		btrfsic_dev_state_init(ds);
+
+	return ds;
+}
+
+static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
+{
+	BUG_ON(!(NULL == ds ||
+		 BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
+	kfree(ds);
+}
+
+static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
+{
+	int i;
+
+	for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
+		INIT_LIST_HEAD(h->table + i);
+}
+
+static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
+					struct btrfsic_block_hashtable *h)
+{
+	const unsigned int hashval =
+	    (((unsigned int)(b->dev_bytenr >> 16)) ^
+	     ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
+	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
+
+	list_add(&b->collision_resolving_node, h->table + hashval);
+}
+
+static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
+{
+	list_del(&b->collision_resolving_node);
+}
+
+static struct btrfsic_block *btrfsic_block_hashtable_lookup(
+		struct block_device *bdev,
+		u64 dev_bytenr,
+		struct btrfsic_block_hashtable *h)
+{
+	const unsigned int hashval =
+	    (((unsigned int)(dev_bytenr >> 16)) ^
+	     ((unsigned int)((uintptr_t)bdev))) &
+	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
+	struct list_head *elem;
+
+	list_for_each(elem, h->table + hashval) {
+		struct btrfsic_block *const b =
+		    list_entry(elem, struct btrfsic_block,
+			       collision_resolving_node);
+
+		if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
+			return b;
+	}
+
+	return NULL;
+}
+
+static void btrfsic_block_link_hashtable_init(
+		struct btrfsic_block_link_hashtable *h)
+{
+	int i;
+
+	for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
+		INIT_LIST_HEAD(h->table + i);
+}
+
+static void btrfsic_block_link_hashtable_add(
+		struct btrfsic_block_link *l,
+		struct btrfsic_block_link_hashtable *h)
+{
+	const unsigned int hashval =
+	    (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
+	     ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
+	     ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
+	     ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
+	     & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
+
+	BUG_ON(NULL == l->block_ref_to);
+	BUG_ON(NULL == l->block_ref_from);
+	list_add(&l->collision_resolving_node, h->table + hashval);
+}
+
+static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
+{
+	list_del(&l->collision_resolving_node);
+}
+
+static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
+		struct block_device *bdev_ref_to,
+		u64 dev_bytenr_ref_to,
+		struct block_device *bdev_ref_from,
+		u64 dev_bytenr_ref_from,
+		struct btrfsic_block_link_hashtable *h)
+{
+	const unsigned int hashval =
+	    (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
+	     ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
+	     ((unsigned int)((uintptr_t)bdev_ref_to)) ^
+	     ((unsigned int)((uintptr_t)bdev_ref_from))) &
+	     (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
+	struct list_head *elem;
+
+	list_for_each(elem, h->table + hashval) {
+		struct btrfsic_block_link *const l =
+		    list_entry(elem, struct btrfsic_block_link,
+			       collision_resolving_node);
+
+		BUG_ON(NULL == l->block_ref_to);
+		BUG_ON(NULL == l->block_ref_from);
+		if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
+		    l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
+		    l->block_ref_from->dev_state->bdev == bdev_ref_from &&
+		    l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
+			return l;
+	}
+
+	return NULL;
+}
+
+static void btrfsic_dev_state_hashtable_init(
+		struct btrfsic_dev_state_hashtable *h)
+{
+	int i;
+
+	for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
+		INIT_LIST_HEAD(h->table + i);
+}
+
+static void btrfsic_dev_state_hashtable_add(
+		struct btrfsic_dev_state *ds,
+		struct btrfsic_dev_state_hashtable *h)
+{
+	const unsigned int hashval =
+	    (((unsigned int)((uintptr_t)ds->bdev)) &
+	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
+
+	list_add(&ds->collision_resolving_node, h->table + hashval);
+}
+
+static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
+{
+	list_del(&ds->collision_resolving_node);
+}
+
+static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
+		struct block_device *bdev,
+		struct btrfsic_dev_state_hashtable *h)
+{
+	const unsigned int hashval =
+	    (((unsigned int)((uintptr_t)bdev)) &
+	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
+	struct list_head *elem;
+
+	list_for_each(elem, h->table + hashval) {
+		struct btrfsic_dev_state *const ds =
+		    list_entry(elem, struct btrfsic_dev_state,
+			       collision_resolving_node);
+
+		if (ds->bdev == bdev)
+			return ds;
+	}
+
+	return NULL;
+}
+
+static int btrfsic_process_superblock(struct btrfsic_state *state,
+				      struct btrfs_fs_devices *fs_devices)
+{
+	int ret;
+	struct btrfs_super_block *selected_super;
+	struct list_head *dev_head = &fs_devices->devices;
+	struct btrfs_device *device;
+	struct btrfsic_dev_state *selected_dev_state = NULL;
+	int pass;
+
+	BUG_ON(NULL == state);
+	selected_super = kmalloc(sizeof(*selected_super), GFP_NOFS);
+	if (NULL == selected_super) {
+		printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
+		return -1;
+	}
+
+	list_for_each_entry(device, dev_head, dev_list) {
+		int i;
+		struct btrfsic_dev_state *dev_state;
+
+		if (!device->bdev || !device->name)
+			continue;
+
+		dev_state = btrfsic_dev_state_lookup(device->bdev);
+		BUG_ON(NULL == dev_state);
+		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+			ret = btrfsic_process_superblock_dev_mirror(
+					state, dev_state, device, i,
+					&selected_dev_state, selected_super);
+			if (0 != ret && 0 == i) {
+				kfree(selected_super);
+				return ret;
+			}
+		}
+	}
+
+	if (NULL == state->latest_superblock) {
+		printk(KERN_INFO "btrfsic: no superblock found!\n");
+		kfree(selected_super);
+		return -1;
+	}
+
+	state->csum_size = btrfs_super_csum_size(selected_super);
+
+	for (pass = 0; pass < 3; pass++) {
+		int num_copies;
+		int mirror_num;
+		u64 next_bytenr;
+
+		switch (pass) {
+		case 0:
+			next_bytenr = btrfs_super_root(selected_super);
+			if (state->print_mask &
+			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
+				printk(KERN_INFO "root@%llu\n",
+				       (unsigned long long)next_bytenr);
+			break;
+		case 1:
+			next_bytenr = btrfs_super_chunk_root(selected_super);
+			if (state->print_mask &
+			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
+				printk(KERN_INFO "chunk@%llu\n",
+				       (unsigned long long)next_bytenr);
+			break;
+		case 2:
+			next_bytenr = btrfs_super_log_root(selected_super);
+			if (0 == next_bytenr)
+				continue;
+			if (state->print_mask &
+			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
+				printk(KERN_INFO "log@%llu\n",
+				       (unsigned long long)next_bytenr);
+			break;
+		}
+
+		num_copies =
+		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
+				     next_bytenr, PAGE_SIZE);
+		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
+			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
+			       (unsigned long long)next_bytenr, num_copies);
+
+		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
+			struct btrfsic_block *next_block;
+			struct btrfsic_block_data_ctx tmp_next_block_ctx;
+			struct btrfsic_block_link *l;
+			struct btrfs_header *hdr;
+
+			ret = btrfsic_map_block(state, next_bytenr, PAGE_SIZE,
+						&tmp_next_block_ctx,
+						mirror_num);
+			if (ret) {
+				printk(KERN_INFO "btrfsic:"
+				       " btrfsic_map_block(root @%llu,"
+				       " mirror %d) failed!\n",
+				       (unsigned long long)next_bytenr,
+				       mirror_num);
+				kfree(selected_super);
+				return -1;
+			}
+
+			next_block = btrfsic_block_hashtable_lookup(
+					tmp_next_block_ctx.dev->bdev,
+					tmp_next_block_ctx.dev_bytenr,
+					&state->block_hashtable);
+			BUG_ON(NULL == next_block);
+
+			l = btrfsic_block_link_hashtable_lookup(
+					tmp_next_block_ctx.dev->bdev,
+					tmp_next_block_ctx.dev_bytenr,
+					state->latest_superblock->dev_state->
+					bdev,
+					state->latest_superblock->dev_bytenr,
+					&state->block_link_hashtable);
+			BUG_ON(NULL == l);
+
+			ret = btrfsic_read_block(state, &tmp_next_block_ctx);
+			if (ret < (int)BTRFSIC_BLOCK_SIZE) {
+				printk(KERN_INFO
+				       "btrfsic: read @logical %llu failed!\n",
+				       (unsigned long long)
+				       tmp_next_block_ctx.start);
+				btrfsic_release_block_ctx(&tmp_next_block_ctx);
+				kfree(selected_super);
+				return -1;
+			}
+
+			hdr = (struct btrfs_header *)tmp_next_block_ctx.data;
+			ret = btrfsic_process_metablock(state,
+							next_block,
+							&tmp_next_block_ctx,
+							hdr,
+							BTRFS_MAX_LEVEL + 3, 1);
+			btrfsic_release_block_ctx(&tmp_next_block_ctx);
+		}
+	}
+
+	kfree(selected_super);
+	return ret;
+}
+
+static int btrfsic_process_superblock_dev_mirror(
+		struct btrfsic_state *state,
+		struct btrfsic_dev_state *dev_state,
+		struct btrfs_device *device,
+		int superblock_mirror_num,
+		struct btrfsic_dev_state **selected_dev_state,
+		struct btrfs_super_block *selected_super)
+{
+	struct btrfs_super_block *super_tmp;
+	u64 dev_bytenr;
+	struct buffer_head *bh;
+	struct btrfsic_block *superblock_tmp;
+	int pass;
+	struct block_device *const superblock_bdev = device->bdev;
+
+	/* super block bytenr is always the unmapped device bytenr */
+	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
+	bh = __bread(superblock_bdev, dev_bytenr / 4096, 4096);
+	if (NULL == bh)
+		return -1;
+	super_tmp = (struct btrfs_super_block *)
+	    (bh->b_data + (dev_bytenr & 4095));
+
+	if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
+	    strncmp((char *)(&(super_tmp->magic)), BTRFS_MAGIC,
+		    sizeof(super_tmp->magic)) ||
+	    memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE)) {
+		brelse(bh);
+		return 0;
+	}
+
+	superblock_tmp =
+	    btrfsic_block_hashtable_lookup(superblock_bdev,
+					   dev_bytenr,
+					   &state->block_hashtable);
+	if (NULL == superblock_tmp) {
+		superblock_tmp = btrfsic_block_alloc();
+		if (NULL == superblock_tmp) {
+			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
+			brelse(bh);
+			return -1;
+		}
+		/* for superblock, only the dev_bytenr makes sense */
+		superblock_tmp->dev_bytenr = dev_bytenr;
+		superblock_tmp->dev_state = dev_state;
+		superblock_tmp->logical_bytenr = dev_bytenr;
+		superblock_tmp->generation = btrfs_super_generation(super_tmp);
+		superblock_tmp->is_metadata = 1;
+		superblock_tmp->is_superblock = 1;
+		superblock_tmp->is_iodone = 1;
+		superblock_tmp->never_written = 0;
+		superblock_tmp->mirror_num = 1 + superblock_mirror_num;
+		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
+			printk(KERN_INFO "New initial S-block (bdev %p, %s)"
+			       " @%llu (%s/%llu/%d)\n",
+			       superblock_bdev, device->name,
+			       (unsigned long long)dev_bytenr,
+			       dev_state->name,
+			       (unsigned long long)dev_bytenr,
+			       superblock_mirror_num);
+		list_add(&superblock_tmp->all_blocks_node,
+			 &state->all_blocks_list);
+		btrfsic_block_hashtable_add(superblock_tmp,
+					    &state->block_hashtable);
+	}
+
+	/* select the one with the highest generation field */
+	if (btrfs_super_generation(super_tmp) >
+	    state->max_superblock_generation ||
+	    0 == state->max_superblock_generation) {
+		memcpy(selected_super, super_tmp, sizeof(*selected_super));
+		*selected_dev_state = dev_state;
+		state->max_superblock_generation =
+		    btrfs_super_generation(super_tmp);
+		state->latest_superblock = superblock_tmp;
+	}
+
+	for (pass = 0; pass < 3; pass++) {
+		u64 next_bytenr;
+		int num_copies;
+		int mirror_num;
+		const char *additional_string = NULL;
+		struct btrfs_disk_key tmp_disk_key;
+
+		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
+		tmp_disk_key.offset = 0;
+		switch (pass) {
+		case 0:
+			tmp_disk_key.objectid =
+			    cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
+			additional_string = "initial root ";
+			next_bytenr = btrfs_super_root(super_tmp);
+			break;
+		case 1:
+			tmp_disk_key.objectid =
+			    cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
+			additional_string = "initial chunk ";
+			next_bytenr = btrfs_super_chunk_root(super_tmp);
+			break;
+		case 2:
+			tmp_disk_key.objectid =
+			    cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
+			additional_string = "initial log ";
+			next_bytenr = btrfs_super_log_root(super_tmp);
+			if (0 == next_bytenr)
+				continue;
+			break;
+		}
+
+		num_copies =
+		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
+				     next_bytenr, PAGE_SIZE);
+		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
+			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
+			       (unsigned long long)next_bytenr, num_copies);
+		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
+			struct btrfsic_block *next_block;
+			struct btrfsic_block_data_ctx tmp_next_block_ctx;
+			struct btrfsic_block_link *l;
+
+			if (btrfsic_map_block(state, next_bytenr, PAGE_SIZE,
+					      &tmp_next_block_ctx,
+					      mirror_num)) {
+				printk(KERN_INFO "btrfsic: btrfsic_map_block("
+				       "bytenr @%llu, mirror %d) failed!\n",
+				       (unsigned long long)next_bytenr,
+				       mirror_num);
+				brelse(bh);
+				return -1;
+			}
+
+			next_block = btrfsic_block_lookup_or_add(
+					state, &tmp_next_block_ctx,
+					additional_string, 1, 1, 0,
+					mirror_num, NULL);
+			if (NULL == next_block) {
+				btrfsic_release_block_ctx(&tmp_next_block_ctx);
+				brelse(bh);
+				return -1;
+			}
+
+			next_block->disk_key = tmp_disk_key;
+			next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
+			l = btrfsic_block_link_lookup_or_add(
+					state, &tmp_next_block_ctx,
+					next_block, superblock_tmp,
+					BTRFSIC_GENERATION_UNKNOWN);
+			btrfsic_release_block_ctx(&tmp_next_block_ctx);
+			if (NULL == l) {
+				brelse(bh);
+				return -1;
+			}
+		}
+	}
+	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
+		btrfsic_dump_tree_sub(state, superblock_tmp, 0);
+
+	brelse(bh);
+	return 0;
+}
+
+static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
+{
+	struct btrfsic_stack_frame *sf;
+
+	sf = kzalloc(sizeof(*sf), GFP_NOFS);
+	if (NULL == sf)
+		printk(KERN_INFO "btrfsic: alloc memory failed!\n");
+	else
+		sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
+	return sf;
+}
+
+static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
+{
+	BUG_ON(!(NULL == sf ||
+		 BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
+	kfree(sf);
+}
+
+static int btrfsic_process_metablock(
+		struct btrfsic_state *state,
+		struct btrfsic_block *const first_block,
+		struct btrfsic_block_data_ctx *const first_block_ctx,
+		struct btrfs_header *const first_hdr,
+		int first_limit_nesting, int force_iodone_flag)
+{
+	struct btrfsic_stack_frame initial_stack_frame = { 0 };
+	struct btrfsic_stack_frame *sf;
+	struct btrfsic_stack_frame *next_stack;
+
+	sf = &initial_stack_frame;
+	sf->error = 0;
+	sf->i = -1;
+	sf->limit_nesting = first_limit_nesting;
+	sf->block = first_block;
+	sf->block_ctx = first_block_ctx;
+	sf->next_block = NULL;
+	sf->hdr = first_hdr;
+	sf->prev = NULL;
+
+continue_with_new_stack_frame:
+	sf->block->generation = le64_to_cpu(sf->hdr->generation);
+	if (0 == sf->hdr->level) {
+		struct btrfs_leaf *const leafhdr =
+		    (struct btrfs_leaf *)sf->hdr;
+
+		if (-1 == sf->i) {
+			sf->nr = le32_to_cpu(leafhdr->header.nritems);
+
+			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+				printk(KERN_INFO
+				       "leaf %llu items %d generation %llu"
+				       " owner %llu\n",
+				       (unsigned long long)
+				       sf->block_ctx->start,
+				       sf->nr,
+				       (unsigned long long)
+				       le64_to_cpu(leafhdr->header.generation),
+				       (unsigned long long)
+				       le64_to_cpu(leafhdr->header.owner));
+		}
+
+continue_with_current_leaf_stack_frame:
+		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
+			sf->i++;
+			sf->num_copies = 0;
+		}
+
+		if (sf->i < sf->nr) {
+			struct btrfs_item *disk_item = leafhdr->items + sf->i;
+			struct btrfs_disk_key *disk_key = &disk_item->key;
+			u8 type;
+			const u32 item_offset = le32_to_cpu(disk_item->offset);
+
+			type = disk_key->type;
+
+			if (BTRFS_ROOT_ITEM_KEY == type) {
+				const struct btrfs_root_item *const root_item =
+				    (struct btrfs_root_item *)
+				    (sf->block_ctx->data +
+				     offsetof(struct btrfs_leaf, items) +
+				     item_offset);
+				const u64 next_bytenr =
+				    le64_to_cpu(root_item->bytenr);
+
+				sf->error =
+				    btrfsic_create_link_to_next_block(
+						state,
+						sf->block,
+						sf->block_ctx,
+						next_bytenr,
+						sf->limit_nesting,
+						&sf->next_block_ctx,
+						&sf->next_block,
+						force_iodone_flag,
+						&sf->num_copies,
+						&sf->mirror_num,
+						disk_key,
+						le64_to_cpu(root_item->
+						generation));
+				if (sf->error)
+					goto one_stack_frame_backwards;
+
+				if (NULL != sf->next_block) {
+					struct btrfs_header *const next_hdr =
+					    (struct btrfs_header *)
+					    sf->next_block_ctx.data;
+
+					next_stack =
+					    btrfsic_stack_frame_alloc();
+					if (NULL == next_stack) {
+						btrfsic_release_block_ctx(
+								&sf->
+								next_block_ctx);
+						goto one_stack_frame_backwards;
+					}
+
+					next_stack->i = -1;
+					next_stack->block = sf->next_block;
+					next_stack->block_ctx =
+					    &sf->next_block_ctx;
+					next_stack->next_block = NULL;
+					next_stack->hdr = next_hdr;
+					next_stack->limit_nesting =
+					    sf->limit_nesting - 1;
+					next_stack->prev = sf;
+					sf = next_stack;
+					goto continue_with_new_stack_frame;
+				}
+			} else if (BTRFS_EXTENT_DATA_KEY == type &&
+				   state->include_extent_data) {
+				sf->error = btrfsic_handle_extent_data(
+						state,
+						sf->block,
+						sf->block_ctx,
+						item_offset,
+						force_iodone_flag);
+				if (sf->error)
+					goto one_stack_frame_backwards;
+			}
+
+			goto continue_with_current_leaf_stack_frame;
+		}
+	} else {
+		struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
+
+		if (-1 == sf->i) {
+			sf->nr = le32_to_cpu(nodehdr->header.nritems);
+
+			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+				printk(KERN_INFO "node %llu level %d items %d"
+				       " generation %llu owner %llu\n",
+				       (unsigned long long)
+				       sf->block_ctx->start,
+				       nodehdr->header.level, sf->nr,
+				       (unsigned long long)
+				       le64_to_cpu(nodehdr->header.generation),
+				       (unsigned long long)
+				       le64_to_cpu(nodehdr->header.owner));
+		}
+
+continue_with_current_node_stack_frame:
+		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
+			sf->i++;
+			sf->num_copies = 0;
+		}
+
+		if (sf->i < sf->nr) {
+			struct btrfs_key_ptr *disk_key_ptr =
+			    nodehdr->ptrs + sf->i;
+			const u64 next_bytenr =
+			    le64_to_cpu(disk_key_ptr->blockptr);
+
+			sf->error = btrfsic_create_link_to_next_block(
+					state,
+					sf->block,
+					sf->block_ctx,
+					next_bytenr,
+					sf->limit_nesting,
+					&sf->next_block_ctx,
+					&sf->next_block,
+					force_iodone_flag,
+					&sf->num_copies,
+					&sf->mirror_num,
+					&disk_key_ptr->key,
+					le64_to_cpu(disk_key_ptr->generation));
+			if (sf->error)
+				goto one_stack_frame_backwards;
+
+			if (NULL != sf->next_block) {
+				struct btrfs_header *const next_hdr =
+				    (struct btrfs_header *)
+				    sf->next_block_ctx.data;
+
+				next_stack = btrfsic_stack_frame_alloc();
+				if (NULL == next_stack)
+					goto one_stack_frame_backwards;
+
+				next_stack->i = -1;
+				next_stack->block = sf->next_block;
+				next_stack->block_ctx = &sf->next_block_ctx;
+				next_stack->next_block = NULL;
+				next_stack->hdr = next_hdr;
+				next_stack->limit_nesting =
+				    sf->limit_nesting - 1;
+				next_stack->prev = sf;
+				sf = next_stack;
+				goto continue_with_new_stack_frame;
+			}
+
+			goto continue_with_current_node_stack_frame;
+		}
+	}
+
+one_stack_frame_backwards:
+	if (NULL != sf->prev) {
+		struct btrfsic_stack_frame *const prev = sf->prev;
+
+		/* the one for the initial block is freed in the caller */
+		btrfsic_release_block_ctx(sf->block_ctx);
+
+		if (sf->error) {
+			prev->error = sf->error;
+			btrfsic_stack_frame_free(sf);
+			sf = prev;
+			goto one_stack_frame_backwards;
+		}
+
+		btrfsic_stack_frame_free(sf);
+		sf = prev;
+		goto continue_with_new_stack_frame;
+	} else {
+		BUG_ON(&initial_stack_frame != sf);
+	}
+
+	return sf->error;
+}
+
+static int btrfsic_create_link_to_next_block(
+		struct btrfsic_state *state,
+		struct btrfsic_block *block,
+		struct btrfsic_block_data_ctx *block_ctx,
+		u64 next_bytenr,
+		int limit_nesting,
+		struct btrfsic_block_data_ctx *next_block_ctx,
+		struct btrfsic_block **next_blockp,
+		int force_iodone_flag,
+		int *num_copiesp, int *mirror_nump,
+		struct btrfs_disk_key *disk_key,
+		u64 parent_generation)
+{
+	struct btrfsic_block *next_block = NULL;
+	int ret;
+	struct btrfsic_block_link *l;
+	int did_alloc_block_link;
+	int block_was_created;
+
+	*next_blockp = NULL;
+	if (0 == *num_copiesp) {
+		*num_copiesp =
+		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
+				     next_bytenr, PAGE_SIZE);
+		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
+			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
+			       (unsigned long long)next_bytenr, *num_copiesp);
+		*mirror_nump = 1;
+	}
+
+	if (*mirror_nump > *num_copiesp)
+		return 0;
+
+	if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+		printk(KERN_INFO
+		       "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
+		       *mirror_nump);
+	ret = btrfsic_map_block(state, next_bytenr,
+				BTRFSIC_BLOCK_SIZE,
+				next_block_ctx, *mirror_nump);
+	if (ret) {
+		printk(KERN_INFO
+		       "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
+		       (unsigned long long)next_bytenr, *mirror_nump);
+		btrfsic_release_block_ctx(next_block_ctx);
+		*next_blockp = NULL;
+		return -1;
+	}
+
+	next_block = btrfsic_block_lookup_or_add(state,
+						 next_block_ctx, "referenced ",
+						 1, force_iodone_flag,
+						 !force_iodone_flag,
+						 *mirror_nump,
+						 &block_was_created);
+	if (NULL == next_block) {
+		btrfsic_release_block_ctx(next_block_ctx);
+		*next_blockp = NULL;
+		return -1;
+	}
+	if (block_was_created) {
+		l = NULL;
+		next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
+	} else {
+		if (next_block->logical_bytenr != next_bytenr &&
+		    !(!next_block->is_metadata &&
+		      0 == next_block->logical_bytenr)) {
+			printk(KERN_INFO
+			       "Referenced block @%llu (%s/%llu/%d)"
+			       " found in hash table, %c,"
+			       " bytenr mismatch (!= stored %llu).\n",
+			       (unsigned long long)next_bytenr,
+			       next_block_ctx->dev->name,
+			       (unsigned long long)next_block_ctx->dev_bytenr,
+			       *mirror_nump,
+			       btrfsic_get_block_type(state, next_block),
+			       (unsigned long long)next_block->logical_bytenr);
+		} else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+			printk(KERN_INFO
+			       "Referenced block @%llu (%s/%llu/%d)"
+			       " found in hash table, %c.\n",
+			       (unsigned long long)next_bytenr,
+			       next_block_ctx->dev->name,
+			       (unsigned long long)next_block_ctx->dev_bytenr,
+			       *mirror_nump,
+			       btrfsic_get_block_type(state, next_block));
+		next_block->logical_bytenr = next_bytenr;
+
+		next_block->mirror_num = *mirror_nump;
+		l = btrfsic_block_link_hashtable_lookup(
+				next_block_ctx->dev->bdev,
+				next_block_ctx->dev_bytenr,
+				block_ctx->dev->bdev,
+				block_ctx->dev_bytenr,
+				&state->block_link_hashtable);
+	}
+
+	next_block->disk_key = *disk_key;
+	if (NULL == l) {
+		l = btrfsic_block_link_alloc();
+		if (NULL == l) {
+			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
+			btrfsic_release_block_ctx(next_block_ctx);
+			*next_blockp = NULL;
+			return -1;
+		}
+
+		did_alloc_block_link = 1;
+		l->block_ref_to = next_block;
+		l->block_ref_from = block;
+		l->ref_cnt = 1;
+		l->parent_generation = parent_generation;
+
+		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+			btrfsic_print_add_link(state, l);
+
+		list_add(&l->node_ref_to, &block->ref_to_list);
+		list_add(&l->node_ref_from, &next_block->ref_from_list);
+
+		btrfsic_block_link_hashtable_add(l,
+						 &state->block_link_hashtable);
+	} else {
+		did_alloc_block_link = 0;
+		if (0 == limit_nesting) {
+			l->ref_cnt++;
+			l->parent_generation = parent_generation;
+			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+				btrfsic_print_add_link(state, l);
+		}
+	}
+
+	if (limit_nesting > 0 && did_alloc_block_link) {
+		ret = btrfsic_read_block(state, next_block_ctx);
+		if (ret < (int)BTRFSIC_BLOCK_SIZE) {
+			printk(KERN_INFO
+			       "btrfsic: read block @logical %llu failed!\n",
+			       (unsigned long long)next_bytenr);
+			btrfsic_release_block_ctx(next_block_ctx);
+			*next_blockp = NULL;
+			return -1;
+		}
+
+		*next_blockp = next_block;
+	} else {
+		*next_blockp = NULL;
+	}
+	(*mirror_nump)++;
+
+	return 0;
+}
+
+static int btrfsic_handle_extent_data(
+		struct btrfsic_state *state,
+		struct btrfsic_block *block,
+		struct btrfsic_block_data_ctx *block_ctx,
+		u32 item_offset, int force_iodone_flag)
+{
+	int ret;
+	struct btrfs_file_extent_item *file_extent_item =
+	    (struct btrfs_file_extent_item *)(block_ctx->data +
+					      offsetof(struct btrfs_leaf,
+						       items) + item_offset);
+	u64 next_bytenr =
+	    le64_to_cpu(file_extent_item->disk_bytenr) +
+	    le64_to_cpu(file_extent_item->offset);
+	u64 num_bytes = le64_to_cpu(file_extent_item->num_bytes);
+	u64 generation = le64_to_cpu(file_extent_item->generation);
+	struct btrfsic_block_link *l;
+
+	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
+		printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
+		       " offset = %llu, num_bytes = %llu\n",
+		       file_extent_item->type,
+		       (unsigned long long)
+		       le64_to_cpu(file_extent_item->disk_bytenr),
+		       (unsigned long long)
+		       le64_to_cpu(file_extent_item->offset),
+		       (unsigned long long)
+		       le64_to_cpu(file_extent_item->num_bytes));
+	if (BTRFS_FILE_EXTENT_REG != file_extent_item->type ||
+	    ((u64)0) == le64_to_cpu(file_extent_item->disk_bytenr))
+		return 0;
+	while (num_bytes > 0) {
+		u32 chunk_len;
+		int num_copies;
+		int mirror_num;
+
+		if (num_bytes > BTRFSIC_BLOCK_SIZE)
+			chunk_len = BTRFSIC_BLOCK_SIZE;
+		else
+			chunk_len = num_bytes;
+
+		num_copies =
+		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
+				     next_bytenr, PAGE_SIZE);
+		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
+			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
+			       (unsigned long long)next_bytenr, num_copies);
+		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
+			struct btrfsic_block_data_ctx next_block_ctx;
+			struct btrfsic_block *next_block;
+			int block_was_created;
+
+			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+				printk(KERN_INFO "btrfsic_handle_extent_data("
+				       "mirror_num=%d)\n", mirror_num);
+			if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
+				printk(KERN_INFO
+				       "\tdisk_bytenr = %llu, num_bytes %u\n",
+				       (unsigned long long)next_bytenr,
+				       chunk_len);
+			ret = btrfsic_map_block(state, next_bytenr,
+						chunk_len, &next_block_ctx,
+						mirror_num);
+			if (ret) {
+				printk(KERN_INFO
+				       "btrfsic: btrfsic_map_block(@%llu,"
+				       " mirror=%d) failed!\n",
+				       (unsigned long long)next_bytenr,
+				       mirror_num);
+				return -1;
+			}
+
+			next_block = btrfsic_block_lookup_or_add(
+					state,
+					&next_block_ctx,
+					"referenced ",
+					0,
+					force_iodone_flag,
+					!force_iodone_flag,
+					mirror_num,
+					&block_was_created);
+			if (NULL == next_block) {
+				printk(KERN_INFO
+				       "btrfsic: error, kmalloc failed!\n");
+				btrfsic_release_block_ctx(&next_block_ctx);
+				return -1;
+			}
+			if (!block_was_created) {
+				if (next_block->logical_bytenr != next_bytenr &&
+				    !(!next_block->is_metadata &&
+				      0 == next_block->logical_bytenr)) {
+					printk(KERN_INFO
+					       "Referenced block"
+					       " @%llu (%s/%llu/%d)"
+					       " found in hash table, D,"
+					       " bytenr mismatch"
+					       " (!= stored %llu).\n",
+					       (unsigned long long)next_bytenr,
+					       next_block_ctx.dev->name,
+					       (unsigned long long)
+					       next_block_ctx.dev_bytenr,
+					       mirror_num,
+					       (unsigned long long)
+					       next_block->logical_bytenr);
+				}
+				next_block->logical_bytenr = next_bytenr;
+				next_block->mirror_num = mirror_num;
+			}
+
+			l = btrfsic_block_link_lookup_or_add(state,
+							     &next_block_ctx,
+							     next_block, block,
+							     generation);
+			btrfsic_release_block_ctx(&next_block_ctx);
+			if (NULL == l)
+				return -1;
+		}
+
+		next_bytenr += chunk_len;
+		num_bytes -= chunk_len;
+	}
+
+	return 0;
+}
+
+static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
+			     struct btrfsic_block_data_ctx *block_ctx_out,
+			     int mirror_num)
+{
+	int ret;
+	u64 length;
+	struct btrfs_bio *multi = NULL;
+	struct btrfs_device *device;
+
+	length = len;
+	ret = btrfs_map_block(&state->root->fs_info->mapping_tree, READ,
+			      bytenr, &length, &multi, mirror_num);
+
+	device = multi->stripes[0].dev;
+	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
+	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
+	block_ctx_out->start = bytenr;
+	block_ctx_out->len = len;
+	block_ctx_out->data = NULL;
+	block_ctx_out->bh = NULL;
+
+	if (0 == ret)
+		kfree(multi);
+	if (NULL == block_ctx_out->dev) {
+		ret = -ENXIO;
+		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
+	}
+
+	return ret;
+}
+
+static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
+				  u32 len, struct block_device *bdev,
+				  struct btrfsic_block_data_ctx *block_ctx_out)
+{
+	block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
+	block_ctx_out->dev_bytenr = bytenr;
+	block_ctx_out->start = bytenr;
+	block_ctx_out->len = len;
+	block_ctx_out->data = NULL;
+	block_ctx_out->bh = NULL;
+	if (NULL != block_ctx_out->dev) {
+		return 0;
+	} else {
+		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
+		return -ENXIO;
+	}
+}
+
+static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
+{
+	if (NULL != block_ctx->bh) {
+		brelse(block_ctx->bh);
+		block_ctx->bh = NULL;
+	}
+}
+
+static int btrfsic_read_block(struct btrfsic_state *state,
+			      struct btrfsic_block_data_ctx *block_ctx)
+{
+	block_ctx->bh = NULL;
+	if (block_ctx->dev_bytenr & 4095) {
+		printk(KERN_INFO
+		       "btrfsic: read_block() with unaligned bytenr %llu\n",
+		       (unsigned long long)block_ctx->dev_bytenr);
+		return -1;
+	}
+	if (block_ctx->len > 4096) {
+		printk(KERN_INFO
+		       "btrfsic: read_block() with too huge size %d\n",
+		       block_ctx->len);
+		return -1;
+	}
+
+	block_ctx->bh = __bread(block_ctx->dev->bdev,
+				block_ctx->dev_bytenr >> 12, 4096);
+	if (NULL == block_ctx->bh)
+		return -1;
+	block_ctx->data = block_ctx->bh->b_data;
+
+	return block_ctx->len;
+}
+
+static void btrfsic_dump_database(struct btrfsic_state *state)
+{
+	struct list_head *elem_all;
+
+	BUG_ON(NULL == state);
+
+	printk(KERN_INFO "all_blocks_list:\n");
+	list_for_each(elem_all, &state->all_blocks_list) {
+		const struct btrfsic_block *const b_all =
+		    list_entry(elem_all, struct btrfsic_block,
+			       all_blocks_node);
+		struct list_head *elem_ref_to;
+		struct list_head *elem_ref_from;
+
+		printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
+		       btrfsic_get_block_type(state, b_all),
+		       (unsigned long long)b_all->logical_bytenr,
+		       b_all->dev_state->name,
+		       (unsigned long long)b_all->dev_bytenr,
+		       b_all->mirror_num);
+
+		list_for_each(elem_ref_to, &b_all->ref_to_list) {
+			const struct btrfsic_block_link *const l =
+			    list_entry(elem_ref_to,
+				       struct btrfsic_block_link,
+				       node_ref_to);
+
+			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
+			       " refers %u* to"
+			       " %c @%llu (%s/%llu/%d)\n",
+			       btrfsic_get_block_type(state, b_all),
+			       (unsigned long long)b_all->logical_bytenr,
+			       b_all->dev_state->name,
+			       (unsigned long long)b_all->dev_bytenr,
+			       b_all->mirror_num,
+			       l->ref_cnt,
+			       btrfsic_get_block_type(state, l->block_ref_to),
+			       (unsigned long long)
+			       l->block_ref_to->logical_bytenr,
+			       l->block_ref_to->dev_state->name,
+			       (unsigned long long)l->block_ref_to->dev_bytenr,
+			       l->block_ref_to->mirror_num);
+		}
+
+		list_for_each(elem_ref_from, &b_all->ref_from_list) {
+			const struct btrfsic_block_link *const l =
+			    list_entry(elem_ref_from,
+				       struct btrfsic_block_link,
+				       node_ref_from);
+
+			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
+			       " is ref %u* from"
+			       " %c @%llu (%s/%llu/%d)\n",
+			       btrfsic_get_block_type(state, b_all),
+			       (unsigned long long)b_all->logical_bytenr,
+			       b_all->dev_state->name,
+			       (unsigned long long)b_all->dev_bytenr,
+			       b_all->mirror_num,
+			       l->ref_cnt,
+			       btrfsic_get_block_type(state, l->block_ref_from),
+			       (unsigned long long)
+			       l->block_ref_from->logical_bytenr,
+			       l->block_ref_from->dev_state->name,
+			       (unsigned long long)
+			       l->block_ref_from->dev_bytenr,
+			       l->block_ref_from->mirror_num);
+		}
+
+		printk(KERN_INFO "\n");
+	}
+}
+
+/*
+ * Test whether the disk block contains a tree block (leaf or node)
+ * (note that this test fails for the super block)
+ */
+static int btrfsic_test_for_metadata(struct btrfsic_state *state,
+				     const u8 *data, unsigned int size)
+{
+	struct btrfs_header *h;
+	u8 csum[BTRFS_CSUM_SIZE];
+	u32 crc = ~(u32)0;
+	int fail = 0;
+	int crc_fail = 0;
+
+	h = (struct btrfs_header *)data;
+
+	if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
+		fail++;
+
+	crc = crc32c(crc, data + BTRFS_CSUM_SIZE, PAGE_SIZE - BTRFS_CSUM_SIZE);
+	btrfs_csum_final(crc, csum);
+	if (memcmp(csum, h->csum, state->csum_size))
+		crc_fail++;
+
+	return fail || crc_fail;
+}
+
+static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
+					  u64 dev_bytenr,
+					  u8 *mapped_data, unsigned int len,
+					  struct bio *bio,
+					  int *bio_is_patched,
+					  struct buffer_head *bh,
+					  int submit_bio_bh_rw)
+{
+	int is_metadata;
+	struct btrfsic_block *block;
+	struct btrfsic_block_data_ctx block_ctx;
+	int ret;
+	struct btrfsic_state *state = dev_state->state;
+	struct block_device *bdev = dev_state->bdev;
+
+	WARN_ON(len > PAGE_SIZE);
+	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_data, len));
+	if (NULL != bio_is_patched)
+		*bio_is_patched = 0;
+
+	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
+					       &state->block_hashtable);
+	if (NULL != block) {
+		u64 bytenr = 0;
+		struct list_head *elem_ref_to;
+		struct list_head *tmp_ref_to;
+
+		if (block->is_superblock) {
+			bytenr = le64_to_cpu(((struct btrfs_super_block *)
+					      mapped_data)->bytenr);
+			is_metadata = 1;
+			if (state->print_mask &
+			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
+				printk(KERN_INFO
+				       "[before new superblock is written]:\n");
+				btrfsic_dump_tree_sub(state, block, 0);
+			}
+		}
+		if (is_metadata) {
+			if (!block->is_superblock) {
+				bytenr = le64_to_cpu(((struct btrfs_header *)
+						      mapped_data)->bytenr);
+				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
+							       dev_state,
+							       dev_bytenr,
+							       mapped_data);
+			}
+			if (block->logical_bytenr != bytenr) {
+				printk(KERN_INFO
+				       "Written block @%llu (%s/%llu/%d)"
+				       " found in hash table, %c,"
+				       " bytenr mismatch"
+				       " (!= stored %llu).\n",
+				       (unsigned long long)bytenr,
+				       dev_state->name,
+				       (unsigned long long)dev_bytenr,
+				       block->mirror_num,
+				       btrfsic_get_block_type(state, block),
+				       (unsigned long long)
+				       block->logical_bytenr);
+				block->logical_bytenr = bytenr;
+			} else if (state->print_mask &
+				   BTRFSIC_PRINT_MASK_VERBOSE)
+				printk(KERN_INFO
+				       "Written block @%llu (%s/%llu/%d)"
+				       " found in hash table, %c.\n",
+				       (unsigned long long)bytenr,
+				       dev_state->name,
+				       (unsigned long long)dev_bytenr,
+				       block->mirror_num,
+				       btrfsic_get_block_type(state, block));
+		} else {
+			bytenr = block->logical_bytenr;
+			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+				printk(KERN_INFO
+				       "Written block @%llu (%s/%llu/%d)"
+				       " found in hash table, %c.\n",
+				       (unsigned long long)bytenr,
+				       dev_state->name,
+				       (unsigned long long)dev_bytenr,
+				       block->mirror_num,
+				       btrfsic_get_block_type(state, block));
+		}
+
+		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+			printk(KERN_INFO
+			       "ref_to_list: %cE, ref_from_list: %cE\n",
+			       list_empty(&block->ref_to_list) ? ' ' : '!',
+			       list_empty(&block->ref_from_list) ? ' ' : '!');
+		if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
+			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
+			       " @%llu (%s/%llu/%d), old(gen=%llu,"
+			       " objectid=%llu, type=%d, offset=%llu),"
+			       " new(gen=%llu),"
+			       " which is referenced by most recent superblock"
+			       " (superblockgen=%llu)!\n",
+			       btrfsic_get_block_type(state, block),
+			       (unsigned long long)bytenr,
+			       dev_state->name,
+			       (unsigned long long)dev_bytenr,
+			       block->mirror_num,
+			       (unsigned long long)block->generation,
+			       (unsigned long long)
+			       le64_to_cpu(block->disk_key.objectid),
+			       block->disk_key.type,
+			       (unsigned long long)
+			       le64_to_cpu(block->disk_key.offset),
+			       (unsigned long long)
+			       le64_to_cpu(((struct btrfs_header *)
+					    mapped_data)->generation),
+			       (unsigned long long)
+			       state->max_superblock_generation);
+			btrfsic_dump_tree(state);
+		}
+
+		if (!block->is_iodone && !block->never_written) {
+			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
+			       " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
+			       " which is not yet iodone!\n",
+			       btrfsic_get_block_type(state, block),
+			       (unsigned long long)bytenr,
+			       dev_state->name,
+			       (unsigned long long)dev_bytenr,
+			       block->mirror_num,
+			       (unsigned long long)block->generation,
+			       (unsigned long long)
+			       le64_to_cpu(((struct btrfs_header *)
+					    mapped_data)->generation));
+			/* it would not be safe to go on */
+			btrfsic_dump_tree(state);
+			return;
+		}
+
+		/*
+		 * Clear all references of this block. Do not free
+		 * the block itself even if is not referenced anymore
+		 * because it still carries valueable information
+		 * like whether it was ever written and IO completed.
+		 */
+		list_for_each_safe(elem_ref_to, tmp_ref_to,
+				   &block->ref_to_list) {
+			struct btrfsic_block_link *const l =
+			    list_entry(elem_ref_to,
+				       struct btrfsic_block_link,
+				       node_ref_to);
+
+			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+				btrfsic_print_rem_link(state, l);
+			l->ref_cnt--;
+			if (0 == l->ref_cnt) {
+				list_del(&l->node_ref_to);
+				list_del(&l->node_ref_from);
+				btrfsic_block_link_hashtable_remove(l);
+				btrfsic_block_link_free(l);
+			}
+		}
+
+		if (block->is_superblock)
+			ret = btrfsic_map_superblock(state, bytenr, len,
+						     bdev, &block_ctx);
+		else
+			ret = btrfsic_map_block(state, bytenr, len,
+						&block_ctx, 0);
+		if (ret) {
+			printk(KERN_INFO
+			       "btrfsic: btrfsic_map_block(root @%llu)"
+			       " failed!\n", (unsigned long long)bytenr);
+			return;
+		}
+		block_ctx.data = mapped_data;
+		/* the following is required in case of writes to mirrors,
+		 * use the same that was used for the lookup */
+		block_ctx.dev = dev_state;
+		block_ctx.dev_bytenr = dev_bytenr;
+
+		if (is_metadata || state->include_extent_data) {
+			block->never_written = 0;
+			block->iodone_w_error = 0;
+			if (NULL != bio) {
+				block->is_iodone = 0;
+				BUG_ON(NULL == bio_is_patched);
+				if (!*bio_is_patched) {
+					block->orig_bio_bh_private =
+					    bio->bi_private;
+					block->orig_bio_bh_end_io.bio =
+					    bio->bi_end_io;
+					block->next_in_same_bio = NULL;
+					bio->bi_private = block;
+					bio->bi_end_io = btrfsic_bio_end_io;
+					*bio_is_patched = 1;
+				} else {
+					struct btrfsic_block *chained_block =
+					    (struct btrfsic_block *)
+					    bio->bi_private;
+
+					BUG_ON(NULL == chained_block);
+					block->orig_bio_bh_private =
+					    chained_block->orig_bio_bh_private;
+					block->orig_bio_bh_end_io.bio =
+					    chained_block->orig_bio_bh_end_io.
+					    bio;
+					block->next_in_same_bio = chained_block;
+					bio->bi_private = block;
+				}
+			} else if (NULL != bh) {
+				block->is_iodone = 0;
+				block->orig_bio_bh_private = bh->b_private;
+				block->orig_bio_bh_end_io.bh = bh->b_end_io;
+				block->next_in_same_bio = NULL;
+				bh->b_private = block;
+				bh->b_end_io = btrfsic_bh_end_io;
+			} else {
+				block->is_iodone = 1;
+				block->orig_bio_bh_private = NULL;
+				block->orig_bio_bh_end_io.bio = NULL;
+				block->next_in_same_bio = NULL;
+			}
+		}
+
+		block->flush_gen = dev_state->last_flush_gen + 1;
+		block->submit_bio_bh_rw = submit_bio_bh_rw;
+		if (is_metadata) {
+			block->logical_bytenr = bytenr;
+			block->is_metadata = 1;
+			if (block->is_superblock) {
+				ret = btrfsic_process_written_superblock(
+						state,
+						block,
+						(struct btrfs_super_block *)
+						mapped_data);
+				if (state->print_mask &
+				    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
+					printk(KERN_INFO
+					"[after new superblock is written]:\n");
+					btrfsic_dump_tree_sub(state, block, 0);
+				}
+			} else {
+				block->mirror_num = 0;	/* unknown */
+				ret = btrfsic_process_metablock(
+						state,
+						block,
+						&block_ctx,
+						(struct btrfs_header *)
+						block_ctx.data,
+						0, 0);
+			}
+			if (ret)
+				printk(KERN_INFO
+				       "btrfsic: btrfsic_process_metablock"
+				       "(root @%llu) failed!\n",
+				       (unsigned long long)dev_bytenr);
+		} else {
+			block->is_metadata = 0;
+			block->mirror_num = 0;	/* unknown */
+			block->generation = BTRFSIC_GENERATION_UNKNOWN;
+			if (!state->include_extent_data
+			    && list_empty(&block->ref_from_list)) {
+				/*
+				 * disk block is overwritten with extent
+				 * data (not meta data) and we are configured
+				 * to not include extent data: take the
+				 * chance and free the block's memory
+				 */
+				btrfsic_block_hashtable_remove(block);
+				list_del(&block->all_blocks_node);
+				btrfsic_block_free(block);
+			}
+		}
+		btrfsic_release_block_ctx(&block_ctx);
+	} else {
+		/* block has not been found in hash table */
+		u64 bytenr;
+
+		if (!is_metadata) {
+			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+				printk(KERN_INFO "Written block (%s/%llu/?)"
+				       " !found in hash table, D.\n",
+				       dev_state->name,
+				       (unsigned long long)dev_bytenr);
+			if (!state->include_extent_data)
+				return;	/* ignore that written D block */
+
+			/* this is getting ugly for the
+			 * include_extent_data case... */
+			bytenr = 0;	/* unknown */
+			block_ctx.start = bytenr;
+			block_ctx.len = len;
+			block_ctx.bh = NULL;
+		} else {
+			bytenr = le64_to_cpu(((struct btrfs_header *)
+					      mapped_data)->bytenr);
+			btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
+						       dev_bytenr,
+						       mapped_data);
+			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+				printk(KERN_INFO
+				       "Written block @%llu (%s/%llu/?)"
+				       " !found in hash table, M.\n",
+				       (unsigned long long)bytenr,
+				       dev_state->name,
+				       (unsigned long long)dev_bytenr);
+
+			ret = btrfsic_map_block(state, bytenr, len, &block_ctx,
+						0);
+			if (ret) {
+				printk(KERN_INFO
+				       "btrfsic: btrfsic_map_block(root @%llu)"
+				       " failed!\n",
+				       (unsigned long long)dev_bytenr);
+				return;
+			}
+		}
+		block_ctx.data = mapped_data;
+		/* the following is required in case of writes to mirrors,
+		 * use the same that was used for the lookup */
+		block_ctx.dev = dev_state;
+		block_ctx.dev_bytenr = dev_bytenr;
+
+		block = btrfsic_block_alloc();
+		if (NULL == block) {
+			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
+			btrfsic_release_block_ctx(&block_ctx);
+			return;
+		}
+		block->dev_state = dev_state;
+		block->dev_bytenr = dev_bytenr;
+		block->logical_bytenr = bytenr;
+		block->is_metadata = is_metadata;
+		block->never_written = 0;
+		block->iodone_w_error = 0;
+		block->mirror_num = 0;	/* unknown */
+		block->flush_gen = dev_state->last_flush_gen + 1;
+		block->submit_bio_bh_rw = submit_bio_bh_rw;
+		if (NULL != bio) {
+			block->is_iodone = 0;
+			BUG_ON(NULL == bio_is_patched);
+			if (!*bio_is_patched) {
+				block->orig_bio_bh_private = bio->bi_private;
+				block->orig_bio_bh_end_io.bio = bio->bi_end_io;
+				block->next_in_same_bio = NULL;
+				bio->bi_private = block;
+				bio->bi_end_io = btrfsic_bio_end_io;
+				*bio_is_patched = 1;
+			} else {
+				struct btrfsic_block *chained_block =
+				    (struct btrfsic_block *)
+				    bio->bi_private;
+
+				BUG_ON(NULL == chained_block);
+				block->orig_bio_bh_private =
+				    chained_block->orig_bio_bh_private;
+				block->orig_bio_bh_end_io.bio =
+				    chained_block->orig_bio_bh_end_io.bio;
+				block->next_in_same_bio = chained_block;
+				bio->bi_private = block;
+			}
+		} else if (NULL != bh) {
+			block->is_iodone = 0;
+			block->orig_bio_bh_private = bh->b_private;
+			block->orig_bio_bh_end_io.bh = bh->b_end_io;
+			block->next_in_same_bio = NULL;
+			bh->b_private = block;
+			bh->b_end_io = btrfsic_bh_end_io;
+		} else {
+			block->is_iodone = 1;
+			block->orig_bio_bh_private = NULL;
+			block->orig_bio_bh_end_io.bio = NULL;
+			block->next_in_same_bio = NULL;
+		}
+		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+			printk(KERN_INFO
+			       "New written %c-block @%llu (%s/%llu/%d)\n",
+			       is_metadata ? 'M' : 'D',
+			       (unsigned long long)block->logical_bytenr,
+			       block->dev_state->name,
+			       (unsigned long long)block->dev_bytenr,
+			       block->mirror_num);
+		list_add(&block->all_blocks_node, &state->all_blocks_list);
+		btrfsic_block_hashtable_add(block, &state->block_hashtable);
+
+		if (is_metadata) {
+			ret = btrfsic_process_metablock(state, block,
+							&block_ctx,
+							(struct btrfs_header *)
+							block_ctx.data, 0, 0);
+			if (ret)
+				printk(KERN_INFO
+				       "btrfsic: process_metablock(root @%llu)"
+				       " failed!\n",
+				       (unsigned long long)dev_bytenr);
+		}
+		btrfsic_release_block_ctx(&block_ctx);
+	}
+}
+
+static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
+{
+	struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
+	int iodone_w_error;
+
+	/* mutex is not held! This is not save if IO is not yet completed
+	 * on umount */
+	iodone_w_error = 0;
+	if (bio_error_status)
+		iodone_w_error = 1;
+
+	BUG_ON(NULL == block);
+	bp->bi_private = block->orig_bio_bh_private;
+	bp->bi_end_io = block->orig_bio_bh_end_io.bio;
+
+	do {
+		struct btrfsic_block *next_block;
+		struct btrfsic_dev_state *const dev_state = block->dev_state;
+
+		if ((dev_state->state->print_mask &
+		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
+			printk(KERN_INFO
+			       "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
+			       bio_error_status,
+			       btrfsic_get_block_type(dev_state->state, block),
+			       (unsigned long long)block->logical_bytenr,
+			       dev_state->name,
+			       (unsigned long long)block->dev_bytenr,
+			       block->mirror_num);
+		next_block = block->next_in_same_bio;
+		block->iodone_w_error = iodone_w_error;
+		if (block->submit_bio_bh_rw & REQ_FLUSH) {
+			dev_state->last_flush_gen++;
+			if ((dev_state->state->print_mask &
+			     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
+				printk(KERN_INFO
+				       "bio_end_io() new %s flush_gen=%llu\n",
+				       dev_state->name,
+				       (unsigned long long)
+				       dev_state->last_flush_gen);
+		}
+		if (block->submit_bio_bh_rw & REQ_FUA)
+			block->flush_gen = 0; /* FUA completed means block is
+					       * on disk */
+		block->is_iodone = 1; /* for FLUSH, this releases the block */
+		block = next_block;
+	} while (NULL != block);
+
+	bp->bi_end_io(bp, bio_error_status);
+}
+
+static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
+{
+	struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
+	int iodone_w_error = !uptodate;
+	struct btrfsic_dev_state *dev_state;
+
+	BUG_ON(NULL == block);
+	dev_state = block->dev_state;
+	if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
+		printk(KERN_INFO
+		       "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
+		       iodone_w_error,
+		       btrfsic_get_block_type(dev_state->state, block),
+		       (unsigned long long)block->logical_bytenr,
+		       block->dev_state->name,
+		       (unsigned long long)block->dev_bytenr,
+		       block->mirror_num);
+
+	block->iodone_w_error = iodone_w_error;
+	if (block->submit_bio_bh_rw & REQ_FLUSH) {
+		dev_state->last_flush_gen++;
+		if ((dev_state->state->print_mask &
+		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
+			printk(KERN_INFO
+			       "bh_end_io() new %s flush_gen=%llu\n",
+			       dev_state->name,
+			       (unsigned long long)dev_state->last_flush_gen);
+	}
+	if (block->submit_bio_bh_rw & REQ_FUA)
+		block->flush_gen = 0; /* FUA completed means block is on disk */
+
+	bh->b_private = block->orig_bio_bh_private;
+	bh->b_end_io = block->orig_bio_bh_end_io.bh;
+	block->is_iodone = 1; /* for FLUSH, this releases the block */
+	bh->b_end_io(bh, uptodate);
+}
+
+static int btrfsic_process_written_superblock(
+		struct btrfsic_state *state,
+		struct btrfsic_block *const superblock,
+		struct btrfs_super_block *const super_hdr)
+{
+	int pass;
+
+	superblock->generation = btrfs_super_generation(super_hdr);
+	if (!(superblock->generation > state->max_superblock_generation ||
+	      0 == state->max_superblock_generation)) {
+		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
+			printk(KERN_INFO
+			       "btrfsic: superblock @%llu (%s/%llu/%d)"
+			       " with old gen %llu <= %llu\n",
+			       (unsigned long long)superblock->logical_bytenr,
+			       superblock->dev_state->name,
+			       (unsigned long long)superblock->dev_bytenr,
+			       superblock->mirror_num,
+			       (unsigned long long)
+			       btrfs_super_generation(super_hdr),
+			       (unsigned long long)
+			       state->max_superblock_generation);
+	} else {
+		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
+			printk(KERN_INFO
+			       "btrfsic: got new superblock @%llu (%s/%llu/%d)"
+			       " with new gen %llu > %llu\n",
+			       (unsigned long long)superblock->logical_bytenr,
+			       superblock->dev_state->name,
+			       (unsigned long long)superblock->dev_bytenr,
+			       superblock->mirror_num,
+			       (unsigned long long)
+			       btrfs_super_generation(super_hdr),
+			       (unsigned long long)
+			       state->max_superblock_generation);
+
+		state->max_superblock_generation =
+		    btrfs_super_generation(super_hdr);
+		state->latest_superblock = superblock;
+	}
+
+	for (pass = 0; pass < 3; pass++) {
+		int ret;
+		u64 next_bytenr;
+		struct btrfsic_block *next_block;
+		struct btrfsic_block_data_ctx tmp_next_block_ctx;
+		struct btrfsic_block_link *l;
+		int num_copies;
+		int mirror_num;
+		const char *additional_string = NULL;
+		struct btrfs_disk_key tmp_disk_key;
+
+		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
+		tmp_disk_key.offset = 0;
+
+		switch (pass) {
+		case 0:
+			tmp_disk_key.objectid =
+			    cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
+			additional_string = "root ";
+			next_bytenr = btrfs_super_root(super_hdr);
+			if (state->print_mask &
+			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
+				printk(KERN_INFO "root@%llu\n",
+				       (unsigned long long)next_bytenr);
+			break;
+		case 1:
+			tmp_disk_key.objectid =
+			    cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
+			additional_string = "chunk ";
+			next_bytenr = btrfs_super_chunk_root(super_hdr);
+			if (state->print_mask &
+			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
+				printk(KERN_INFO "chunk@%llu\n",
+				       (unsigned long long)next_bytenr);
+			break;
+		case 2:
+			tmp_disk_key.objectid =
+			    cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
+			additional_string = "log ";
+			next_bytenr = btrfs_super_log_root(super_hdr);
+			if (0 == next_bytenr)
+				continue;
+			if (state->print_mask &
+			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
+				printk(KERN_INFO "log@%llu\n",
+				       (unsigned long long)next_bytenr);
+			break;
+		}
+
+		num_copies =
+		    btrfs_num_copies(&state->root->fs_info->mapping_tree,
+				     next_bytenr, PAGE_SIZE);
+		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
+			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
+			       (unsigned long long)next_bytenr, num_copies);
+		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
+			int was_created;
+
+			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+				printk(KERN_INFO
+				       "btrfsic_process_written_superblock("
+				       "mirror_num=%d)\n", mirror_num);
+			ret = btrfsic_map_block(state, next_bytenr, PAGE_SIZE,
+						&tmp_next_block_ctx,
+						mirror_num);
+			if (ret) {
+				printk(KERN_INFO
+				       "btrfsic: btrfsic_map_block(@%llu,"
+				       " mirror=%d) failed!\n",
+				       (unsigned long long)next_bytenr,
+				       mirror_num);
+				return -1;
+			}
+
+			next_block = btrfsic_block_lookup_or_add(
+					state,
+					&tmp_next_block_ctx,
+					additional_string,
+					1, 0, 1,
+					mirror_num,
+					&was_created);
+			if (NULL == next_block) {
+				printk(KERN_INFO
+				       "btrfsic: error, kmalloc failed!\n");
+				btrfsic_release_block_ctx(&tmp_next_block_ctx);
+				return -1;
+			}
+
+			next_block->disk_key = tmp_disk_key;
+			if (was_created)
+				next_block->generation =
+				    BTRFSIC_GENERATION_UNKNOWN;
+			l = btrfsic_block_link_lookup_or_add(
+					state,
+					&tmp_next_block_ctx,
+					next_block,
+					superblock,
+					BTRFSIC_GENERATION_UNKNOWN);
+			btrfsic_release_block_ctx(&tmp_next_block_ctx);
+			if (NULL == l)
+				return -1;
+		}
+	}
+
+	if (-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)) {
+		WARN_ON(1);
+		btrfsic_dump_tree(state);
+	}
+
+	return 0;
+}
+
+static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
+					struct btrfsic_block *const block,
+					int recursion_level)
+{
+	struct list_head *elem_ref_to;
+	int ret = 0;
+
+	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
+		/*
+		 * Note that this situation can happen and does not
+		 * indicate an error in regular cases. It happens
+		 * when disk blocks are freed and later reused.
+		 * The check-integrity module is not aware of any
+		 * block free operations, it just recognizes block
+		 * write operations. Therefore it keeps the linkage
+		 * information for a block until a block is
+		 * rewritten. This can temporarily cause incorrect
+		 * and even circular linkage informations. This
+		 * causes no harm unless such blocks are referenced
+		 * by the most recent super block.
+		 */
+		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+			printk(KERN_INFO
+			       "btrfsic: abort cyclic linkage (case 1).\n");
+
+		return ret;
+	}
+
+	/*
+	 * This algorithm is recursive because the amount of used stack
+	 * space is very small and the max recursion depth is limited.
+	 */
+	list_for_each(elem_ref_to, &block->ref_to_list) {
+		const struct btrfsic_block_link *const l =
+		    list_entry(elem_ref_to, struct btrfsic_block_link,
+			       node_ref_to);
+
+		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+			printk(KERN_INFO
+			       "rl=%d, %c @%llu (%s/%llu/%d)"
+			       " %u* refers to %c @%llu (%s/%llu/%d)\n",
+			       recursion_level,
+			       btrfsic_get_block_type(state, block),
+			       (unsigned long long)block->logical_bytenr,
+			       block->dev_state->name,
+			       (unsigned long long)block->dev_bytenr,
+			       block->mirror_num,
+			       l->ref_cnt,
+			       btrfsic_get_block_type(state, l->block_ref_to),
+			       (unsigned long long)
+			       l->block_ref_to->logical_bytenr,
+			       l->block_ref_to->dev_state->name,
+			       (unsigned long long)l->block_ref_to->dev_bytenr,
+			       l->block_ref_to->mirror_num);
+		if (l->block_ref_to->never_written) {
+			printk(KERN_INFO "btrfs: attempt to write superblock"
+			       " which references block %c @%llu (%s/%llu/%d)"
+			       " which is never written!\n",
+			       btrfsic_get_block_type(state, l->block_ref_to),
+			       (unsigned long long)
+			       l->block_ref_to->logical_bytenr,
+			       l->block_ref_to->dev_state->name,
+			       (unsigned long long)l->block_ref_to->dev_bytenr,
+			       l->block_ref_to->mirror_num);
+			ret = -1;
+		} else if (!l->block_ref_to->is_iodone) {
+			printk(KERN_INFO "btrfs: attempt to write superblock"
+			       " which references block %c @%llu (%s/%llu/%d)"
+			       " which is not yet iodone!\n",
+			       btrfsic_get_block_type(state, l->block_ref_to),
+			       (unsigned long long)
+			       l->block_ref_to->logical_bytenr,
+			       l->block_ref_to->dev_state->name,
+			       (unsigned long long)l->block_ref_to->dev_bytenr,
+			       l->block_ref_to->mirror_num);
+			ret = -1;
+		} else if (l->parent_generation !=
+			   l->block_ref_to->generation &&
+			   BTRFSIC_GENERATION_UNKNOWN !=
+			   l->parent_generation &&
+			   BTRFSIC_GENERATION_UNKNOWN !=
+			   l->block_ref_to->generation) {
+			printk(KERN_INFO "btrfs: attempt to write superblock"
+			       " which references block %c @%llu (%s/%llu/%d)"
+			       " with generation %llu !="
+			       " parent generation %llu!\n",
+			       btrfsic_get_block_type(state, l->block_ref_to),
+			       (unsigned long long)
+			       l->block_ref_to->logical_bytenr,
+			       l->block_ref_to->dev_state->name,
+			       (unsigned long long)l->block_ref_to->dev_bytenr,
+			       l->block_ref_to->mirror_num,
+			       (unsigned long long)l->block_ref_to->generation,
+			       (unsigned long long)l->parent_generation);
+			ret = -1;
+		} else if (l->block_ref_to->flush_gen >
+			   l->block_ref_to->dev_state->last_flush_gen) {
+			printk(KERN_INFO "btrfs: attempt to write superblock"
+			       " which references block %c @%llu (%s/%llu/%d)"
+			       " which is not flushed out of disk's write cache"
+			       " (block flush_gen=%llu,"
+			       " dev->flush_gen=%llu)!\n",
+			       btrfsic_get_block_type(state, l->block_ref_to),
+			       (unsigned long long)
+			       l->block_ref_to->logical_bytenr,
+			       l->block_ref_to->dev_state->name,
+			       (unsigned long long)l->block_ref_to->dev_bytenr,
+			       l->block_ref_to->mirror_num,
+			       (unsigned long long)block->flush_gen,
+			       (unsigned long long)
+			       l->block_ref_to->dev_state->last_flush_gen);
+			ret = -1;
+		} else if (-1 == btrfsic_check_all_ref_blocks(state,
+							      l->block_ref_to,
+							      recursion_level +
+							      1)) {
+			ret = -1;
+		}
+	}
+
+	return ret;
+}
+
+static int btrfsic_is_block_ref_by_superblock(
+		const struct btrfsic_state *state,
+		const struct btrfsic_block *block,
+		int recursion_level)
+{
+	struct list_head *elem_ref_from;
+
+	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
+		/* refer to comment at "abort cyclic linkage (case 1)" */
+		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+			printk(KERN_INFO
+			       "btrfsic: abort cyclic linkage (case 2).\n");
+
+		return 0;
+	}
+
+	/*
+	 * This algorithm is recursive because the amount of used stack space
+	 * is very small and the max recursion depth is limited.
+	 */
+	list_for_each(elem_ref_from, &block->ref_from_list) {
+		const struct btrfsic_block_link *const l =
+		    list_entry(elem_ref_from, struct btrfsic_block_link,
+			       node_ref_from);
+
+		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+			printk(KERN_INFO
+			       "rl=%d, %c @%llu (%s/%llu/%d)"
+			       " is ref %u* from %c @%llu (%s/%llu/%d)\n",
+			       recursion_level,
+			       btrfsic_get_block_type(state, block),
+			       (unsigned long long)block->logical_bytenr,
+			       block->dev_state->name,
+			       (unsigned long long)block->dev_bytenr,
+			       block->mirror_num,
+			       l->ref_cnt,
+			       btrfsic_get_block_type(state, l->block_ref_from),
+			       (unsigned long long)
+			       l->block_ref_from->logical_bytenr,
+			       l->block_ref_from->dev_state->name,
+			       (unsigned long long)
+			       l->block_ref_from->dev_bytenr,
+			       l->block_ref_from->mirror_num);
+		if (l->block_ref_from->is_superblock &&
+		    state->latest_superblock->dev_bytenr ==
+		    l->block_ref_from->dev_bytenr &&
+		    state->latest_superblock->dev_state->bdev ==
+		    l->block_ref_from->dev_state->bdev)
+			return 1;
+		else if (btrfsic_is_block_ref_by_superblock(state,
+							    l->block_ref_from,
+							    recursion_level +
+							    1))
+			return 1;
+	}
+
+	return 0;
+}
+
+static void btrfsic_print_add_link(const struct btrfsic_state *state,
+				   const struct btrfsic_block_link *l)
+{
+	printk(KERN_INFO
+	       "Add %u* link from %c @%llu (%s/%llu/%d)"
+	       " to %c @%llu (%s/%llu/%d).\n",
+	       l->ref_cnt,
+	       btrfsic_get_block_type(state, l->block_ref_from),
+	       (unsigned long long)l->block_ref_from->logical_bytenr,
+	       l->block_ref_from->dev_state->name,
+	       (unsigned long long)l->block_ref_from->dev_bytenr,
+	       l->block_ref_from->mirror_num,
+	       btrfsic_get_block_type(state, l->block_ref_to),
+	       (unsigned long long)l->block_ref_to->logical_bytenr,
+	       l->block_ref_to->dev_state->name,
+	       (unsigned long long)l->block_ref_to->dev_bytenr,
+	       l->block_ref_to->mirror_num);
+}
+
+static void btrfsic_print_rem_link(const struct btrfsic_state *state,
+				   const struct btrfsic_block_link *l)
+{
+	printk(KERN_INFO
+	       "Rem %u* link from %c @%llu (%s/%llu/%d)"
+	       " to %c @%llu (%s/%llu/%d).\n",
+	       l->ref_cnt,
+	       btrfsic_get_block_type(state, l->block_ref_from),
+	       (unsigned long long)l->block_ref_from->logical_bytenr,
+	       l->block_ref_from->dev_state->name,
+	       (unsigned long long)l->block_ref_from->dev_bytenr,
+	       l->block_ref_from->mirror_num,
+	       btrfsic_get_block_type(state, l->block_ref_to),
+	       (unsigned long long)l->block_ref_to->logical_bytenr,
+	       l->block_ref_to->dev_state->name,
+	       (unsigned long long)l->block_ref_to->dev_bytenr,
+	       l->block_ref_to->mirror_num);
+}
+
+static char btrfsic_get_block_type(const struct btrfsic_state *state,
+				   const struct btrfsic_block *block)
+{
+	if (block->is_superblock &&
+	    state->latest_superblock->dev_bytenr == block->dev_bytenr &&
+	    state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
+		return 'S';
+	else if (block->is_superblock)
+		return 's';
+	else if (block->is_metadata)
+		return 'M';
+	else
+		return 'D';
+}
+
+static void btrfsic_dump_tree(const struct btrfsic_state *state)
+{
+	btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
+}
+
+static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
+				  const struct btrfsic_block *block,
+				  int indent_level)
+{
+	struct list_head *elem_ref_to;
+	int indent_add;
+	static char buf[80];
+	int cursor_position;
+
+	/*
+	 * Should better fill an on-stack buffer with a complete line and
+	 * dump it at once when it is time to print a newline character.
+	 */
+
+	/*
+	 * This algorithm is recursive because the amount of used stack space
+	 * is very small and the max recursion depth is limited.
+	 */
+	indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
+			     btrfsic_get_block_type(state, block),
+			     (unsigned long long)block->logical_bytenr,
+			     block->dev_state->name,
+			     (unsigned long long)block->dev_bytenr,
+			     block->mirror_num);
+	if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
+		printk("[...]\n");
+		return;
+	}
+	printk(buf);
+	indent_level += indent_add;
+	if (list_empty(&block->ref_to_list)) {
+		printk("\n");
+		return;
+	}
+	if (block->mirror_num > 1 &&
+	    !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
+		printk(" [...]\n");
+		return;
+	}
+
+	cursor_position = indent_level;
+	list_for_each(elem_ref_to, &block->ref_to_list) {
+		const struct btrfsic_block_link *const l =
+		    list_entry(elem_ref_to, struct btrfsic_block_link,
+			       node_ref_to);
+
+		while (cursor_position < indent_level) {
+			printk(" ");
+			cursor_position++;
+		}
+		if (l->ref_cnt > 1)
+			indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
+		else
+			indent_add = sprintf(buf, " --> ");
+		if (indent_level + indent_add >
+		    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
+			printk("[...]\n");
+			cursor_position = 0;
+			continue;
+		}
+
+		printk(buf);
+
+		btrfsic_dump_tree_sub(state, l->block_ref_to,
+				      indent_level + indent_add);
+		cursor_position = 0;
+	}
+}
+
+static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
+		struct btrfsic_state *state,
+		struct btrfsic_block_data_ctx *next_block_ctx,
+		struct btrfsic_block *next_block,
+		struct btrfsic_block *from_block,
+		u64 parent_generation)
+{
+	struct btrfsic_block_link *l;
+
+	l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
+						next_block_ctx->dev_bytenr,
+						from_block->dev_state->bdev,
+						from_block->dev_bytenr,
+						&state->block_link_hashtable);
+	if (NULL == l) {
+		l = btrfsic_block_link_alloc();
+		if (NULL == l) {
+			printk(KERN_INFO
+			       "btrfsic: error, kmalloc" " failed!\n");
+			return NULL;
+		}
+
+		l->block_ref_to = next_block;
+		l->block_ref_from = from_block;
+		l->ref_cnt = 1;
+		l->parent_generation = parent_generation;
+
+		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+			btrfsic_print_add_link(state, l);
+
+		list_add(&l->node_ref_to, &from_block->ref_to_list);
+		list_add(&l->node_ref_from, &next_block->ref_from_list);
+
+		btrfsic_block_link_hashtable_add(l,
+						 &state->block_link_hashtable);
+	} else {
+		l->ref_cnt++;
+		l->parent_generation = parent_generation;
+		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+			btrfsic_print_add_link(state, l);
+	}
+
+	return l;
+}
+
+static struct btrfsic_block *btrfsic_block_lookup_or_add(
+		struct btrfsic_state *state,
+		struct btrfsic_block_data_ctx *block_ctx,
+		const char *additional_string,
+		int is_metadata,
+		int is_iodone,
+		int never_written,
+		int mirror_num,
+		int *was_created)
+{
+	struct btrfsic_block *block;
+
+	block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
+					       block_ctx->dev_bytenr,
+					       &state->block_hashtable);
+	if (NULL == block) {
+		struct btrfsic_dev_state *dev_state;
+
+		block = btrfsic_block_alloc();
+		if (NULL == block) {
+			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
+			return NULL;
+		}
+		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
+		if (NULL == dev_state) {
+			printk(KERN_INFO
+			       "btrfsic: error, lookup dev_state failed!\n");
+			btrfsic_block_free(block);
+			return NULL;
+		}
+		block->dev_state = dev_state;
+		block->dev_bytenr = block_ctx->dev_bytenr;
+		block->logical_bytenr = block_ctx->start;
+		block->is_metadata = is_metadata;
+		block->is_iodone = is_iodone;
+		block->never_written = never_written;
+		block->mirror_num = mirror_num;
+		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+			printk(KERN_INFO
+			       "New %s%c-block @%llu (%s/%llu/%d)\n",
+			       additional_string,
+			       btrfsic_get_block_type(state, block),
+			       (unsigned long long)block->logical_bytenr,
+			       dev_state->name,
+			       (unsigned long long)block->dev_bytenr,
+			       mirror_num);
+		list_add(&block->all_blocks_node, &state->all_blocks_list);
+		btrfsic_block_hashtable_add(block, &state->block_hashtable);
+		if (NULL != was_created)
+			*was_created = 1;
+	} else {
+		if (NULL != was_created)
+			*was_created = 0;
+	}
+
+	return block;
+}
+
+static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
+					   u64 bytenr,
+					   struct btrfsic_dev_state *dev_state,
+					   u64 dev_bytenr, char *data)
+{
+	int num_copies;
+	int mirror_num;
+	int ret;
+	struct btrfsic_block_data_ctx block_ctx;
+	int match = 0;
+
+	num_copies = btrfs_num_copies(&state->root->fs_info->mapping_tree,
+				      bytenr, PAGE_SIZE);
+
+	for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
+		ret = btrfsic_map_block(state, bytenr, PAGE_SIZE,
+					&block_ctx, mirror_num);
+		if (ret) {
+			printk(KERN_INFO "btrfsic:"
+			       " btrfsic_map_block(logical @%llu,"
+			       " mirror %d) failed!\n",
+			       (unsigned long long)bytenr, mirror_num);
+			continue;
+		}
+
+		if (dev_state->bdev == block_ctx.dev->bdev &&
+		    dev_bytenr == block_ctx.dev_bytenr) {
+			match++;
+			btrfsic_release_block_ctx(&block_ctx);
+			break;
+		}
+		btrfsic_release_block_ctx(&block_ctx);
+	}
+
+	if (!match) {
+		printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
+		       " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
+		       " phys_bytenr=%llu)!\n",
+		       (unsigned long long)bytenr, dev_state->name,
+		       (unsigned long long)dev_bytenr);
+		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
+			ret = btrfsic_map_block(state, bytenr, PAGE_SIZE,
+						&block_ctx, mirror_num);
+			if (ret)
+				continue;
+
+			printk(KERN_INFO "Read logical bytenr @%llu maps to"
+			       " (%s/%llu/%d)\n",
+			       (unsigned long long)bytenr,
+			       block_ctx.dev->name,
+			       (unsigned long long)block_ctx.dev_bytenr,
+			       mirror_num);
+		}
+		WARN_ON(1);
+	}
+}
+
+static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
+		struct block_device *bdev)
+{
+	struct btrfsic_dev_state *ds;
+
+	ds = btrfsic_dev_state_hashtable_lookup(bdev,
+						&btrfsic_dev_state_hashtable);
+	return ds;
+}
+
+int btrfsic_submit_bh(int rw, struct buffer_head *bh)
+{
+	struct btrfsic_dev_state *dev_state;
+
+	if (!btrfsic_is_initialized)
+		return submit_bh(rw, bh);
+
+	mutex_lock(&btrfsic_mutex);
+	/* since btrfsic_submit_bh() might also be called before
+	 * btrfsic_mount(), this might return NULL */
+	dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
+
+	/* Only called to write the superblock (incl. FLUSH/FUA) */
+	if (NULL != dev_state &&
+	    (rw & WRITE) && bh->b_size > 0) {
+		u64 dev_bytenr;
+
+		dev_bytenr = 4096 * bh->b_blocknr;
+		if (dev_state->state->print_mask &
+		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
+			printk(KERN_INFO
+			       "submit_bh(rw=0x%x, blocknr=%lu (bytenr %llu),"
+			       " size=%lu, data=%p, bdev=%p)\n",
+			       rw, (unsigned long)bh->b_blocknr,
+			       (unsigned long long)dev_bytenr,
+			       (unsigned long)bh->b_size, bh->b_data,
+			       bh->b_bdev);
+		btrfsic_process_written_block(dev_state, dev_bytenr,
+					      bh->b_data, bh->b_size, NULL,
+					      NULL, bh, rw);
+	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
+		if (dev_state->state->print_mask &
+		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
+			printk(KERN_INFO
+			       "submit_bh(rw=0x%x) FLUSH, bdev=%p)\n",
+			       rw, bh->b_bdev);
+		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
+			if ((dev_state->state->print_mask &
+			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
+			      BTRFSIC_PRINT_MASK_VERBOSE)))
+				printk(KERN_INFO
+				       "btrfsic_submit_bh(%s) with FLUSH"
+				       " but dummy block already in use"
+				       " (ignored)!\n",
+				       dev_state->name);
+		} else {
+			struct btrfsic_block *const block =
+				&dev_state->dummy_block_for_bio_bh_flush;
+
+			block->is_iodone = 0;
+			block->never_written = 0;
+			block->iodone_w_error = 0;
+			block->flush_gen = dev_state->last_flush_gen + 1;
+			block->submit_bio_bh_rw = rw;
+			block->orig_bio_bh_private = bh->b_private;
+			block->orig_bio_bh_end_io.bh = bh->b_end_io;
+			block->next_in_same_bio = NULL;
+			bh->b_private = block;
+			bh->b_end_io = btrfsic_bh_end_io;
+		}
+	}
+	mutex_unlock(&btrfsic_mutex);
+	return submit_bh(rw, bh);
+}
+
+void btrfsic_submit_bio(int rw, struct bio *bio)
+{
+	struct btrfsic_dev_state *dev_state;
+
+	if (!btrfsic_is_initialized) {
+		submit_bio(rw, bio);
+		return;
+	}
+
+	mutex_lock(&btrfsic_mutex);
+	/* since btrfsic_submit_bio() is also called before
+	 * btrfsic_mount(), this might return NULL */
+	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
+	if (NULL != dev_state &&
+	    (rw & WRITE) && NULL != bio->bi_io_vec) {
+		unsigned int i;
+		u64 dev_bytenr;
+		int bio_is_patched;
+
+		dev_bytenr = 512 * bio->bi_sector;
+		bio_is_patched = 0;
+		if (dev_state->state->print_mask &
+		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
+			printk(KERN_INFO
+			       "submit_bio(rw=0x%x, bi_vcnt=%u,"
+			       " bi_sector=%lu (bytenr %llu), bi_bdev=%p)\n",
+			       rw, bio->bi_vcnt, (unsigned long)bio->bi_sector,
+			       (unsigned long long)dev_bytenr,
+			       bio->bi_bdev);
+
+		for (i = 0; i < bio->bi_vcnt; i++) {
+			u8 *mapped_data;
+
+			mapped_data = kmap(bio->bi_io_vec[i].bv_page);
+			if ((BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
+			     BTRFSIC_PRINT_MASK_VERBOSE) ==
+			    (dev_state->state->print_mask &
+			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
+			      BTRFSIC_PRINT_MASK_VERBOSE)))
+				printk(KERN_INFO
+				       "#%u: page=%p, mapped=%p, len=%u,"
+				       " offset=%u\n",
+				       i, bio->bi_io_vec[i].bv_page,
+				       mapped_data,
+				       bio->bi_io_vec[i].bv_len,
+				       bio->bi_io_vec[i].bv_offset);
+			btrfsic_process_written_block(dev_state, dev_bytenr,
+						      mapped_data,
+						      bio->bi_io_vec[i].bv_len,
+						      bio, &bio_is_patched,
+						      NULL, rw);
+			kunmap(bio->bi_io_vec[i].bv_page);
+			dev_bytenr += bio->bi_io_vec[i].bv_len;
+		}
+	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
+		if (dev_state->state->print_mask &
+		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
+			printk(KERN_INFO
+			       "submit_bio(rw=0x%x) FLUSH, bdev=%p)\n",
+			       rw, bio->bi_bdev);
+		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
+			if ((dev_state->state->print_mask &
+			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
+			      BTRFSIC_PRINT_MASK_VERBOSE)))
+				printk(KERN_INFO
+				       "btrfsic_submit_bio(%s) with FLUSH"
+				       " but dummy block already in use"
+				       " (ignored)!\n",
+				       dev_state->name);
+		} else {
+			struct btrfsic_block *const block =
+				&dev_state->dummy_block_for_bio_bh_flush;
+
+			block->is_iodone = 0;
+			block->never_written = 0;
+			block->iodone_w_error = 0;
+			block->flush_gen = dev_state->last_flush_gen + 1;
+			block->submit_bio_bh_rw = rw;
+			block->orig_bio_bh_private = bio->bi_private;
+			block->orig_bio_bh_end_io.bio = bio->bi_end_io;
+			block->next_in_same_bio = NULL;
+			bio->bi_private = block;
+			bio->bi_end_io = btrfsic_bio_end_io;
+		}
+	}
+	mutex_unlock(&btrfsic_mutex);
+
+	submit_bio(rw, bio);
+}
+
+int btrfsic_mount(struct btrfs_root *root,
+		  struct btrfs_fs_devices *fs_devices,
+		  int including_extent_data, u32 print_mask)
+{
+	int ret;
+	struct btrfsic_state *state;
+	struct list_head *dev_head = &fs_devices->devices;
+	struct btrfs_device *device;
+
+	state = kzalloc(sizeof(*state), GFP_NOFS);
+	if (NULL == state) {
+		printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
+		return -1;
+	}
+
+	if (!btrfsic_is_initialized) {
+		mutex_init(&btrfsic_mutex);
+		btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
+		btrfsic_is_initialized = 1;
+	}
+	mutex_lock(&btrfsic_mutex);
+	state->root = root;
+	state->print_mask = print_mask;
+	state->include_extent_data = including_extent_data;
+	state->csum_size = 0;
+	INIT_LIST_HEAD(&state->all_blocks_list);
+	btrfsic_block_hashtable_init(&state->block_hashtable);
+	btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
+	state->max_superblock_generation = 0;
+	state->latest_superblock = NULL;
+
+	list_for_each_entry(device, dev_head, dev_list) {
+		struct btrfsic_dev_state *ds;
+		char *p;
+
+		if (!device->bdev || !device->name)
+			continue;
+
+		ds = btrfsic_dev_state_alloc();
+		if (NULL == ds) {
+			printk(KERN_INFO
+			       "btrfs check-integrity: kmalloc() failed!\n");
+			mutex_unlock(&btrfsic_mutex);
+			return -1;
+		}
+		ds->bdev = device->bdev;
+		ds->state = state;
+		bdevname(ds->bdev, ds->name);
+		ds->name[BDEVNAME_SIZE - 1] = '\0';
+		for (p = ds->name; *p != '\0'; p++);
+		while (p > ds->name && *p != '/')
+			p--;
+		if (*p == '/')
+			p++;
+		strlcpy(ds->name, p, sizeof(ds->name));
+		btrfsic_dev_state_hashtable_add(ds,
+						&btrfsic_dev_state_hashtable);
+	}
+
+	ret = btrfsic_process_superblock(state, fs_devices);
+	if (0 != ret) {
+		mutex_unlock(&btrfsic_mutex);
+		btrfsic_unmount(root, fs_devices);
+		return ret;
+	}
+
+	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
+		btrfsic_dump_database(state);
+	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
+		btrfsic_dump_tree(state);
+
+	mutex_unlock(&btrfsic_mutex);
+	return 0;
+}
+
+void btrfsic_unmount(struct btrfs_root *root,
+		     struct btrfs_fs_devices *fs_devices)
+{
+	struct list_head *elem_all;
+	struct list_head *tmp_all;
+	struct btrfsic_state *state;
+	struct list_head *dev_head = &fs_devices->devices;
+	struct btrfs_device *device;
+
+	if (!btrfsic_is_initialized)
+		return;
+
+	mutex_lock(&btrfsic_mutex);
+
+	state = NULL;
+	list_for_each_entry(device, dev_head, dev_list) {
+		struct btrfsic_dev_state *ds;
+
+		if (!device->bdev || !device->name)
+			continue;
+
+		ds = btrfsic_dev_state_hashtable_lookup(
+				device->bdev,
+				&btrfsic_dev_state_hashtable);
+		if (NULL != ds) {
+			state = ds->state;
+			btrfsic_dev_state_hashtable_remove(ds);
+			btrfsic_dev_state_free(ds);
+		}
+	}
+
+	if (NULL == state) {
+		printk(KERN_INFO
+		       "btrfsic: error, cannot find state information"
+		       " on umount!\n");
+		mutex_unlock(&btrfsic_mutex);
+		return;
+	}
+
+	/*
+	 * Don't care about keeping the lists' state up to date,
+	 * just free all memory that was allocated dynamically.
+	 * Free the blocks and the block_links.
+	 */
+	list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
+		struct btrfsic_block *const b_all =
+		    list_entry(elem_all, struct btrfsic_block,
+			       all_blocks_node);
+		struct list_head *elem_ref_to;
+		struct list_head *tmp_ref_to;
+
+		list_for_each_safe(elem_ref_to, tmp_ref_to,
+				   &b_all->ref_to_list) {
+			struct btrfsic_block_link *const l =
+			    list_entry(elem_ref_to,
+				       struct btrfsic_block_link,
+				       node_ref_to);
+
+			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
+				btrfsic_print_rem_link(state, l);
+
+			l->ref_cnt--;
+			if (0 == l->ref_cnt)
+				btrfsic_block_link_free(l);
+		}
+
+		if (b_all->is_iodone)
+			btrfsic_block_free(b_all);
+		else
+			printk(KERN_INFO "btrfs: attempt to free %c-block"
+			       " @%llu (%s/%llu/%d) on umount which is"
+			       " not yet iodone!\n",
+			       btrfsic_get_block_type(state, b_all),
+			       (unsigned long long)b_all->logical_bytenr,
+			       b_all->dev_state->name,
+			       (unsigned long long)b_all->dev_bytenr,
+			       b_all->mirror_num);
+	}
+
+	mutex_unlock(&btrfsic_mutex);
+
+	kfree(state);
+}
diff --git a/fs/btrfs/check-integrity.h b/fs/btrfs/check-integrity.h
new file mode 100644
index 00000000000..8b59175cc50
--- /dev/null
+++ b/fs/btrfs/check-integrity.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) STRATO AG 2011.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#if !defined(__BTRFS_CHECK_INTEGRITY__)
+#define __BTRFS_CHECK_INTEGRITY__
+
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+int btrfsic_submit_bh(int rw, struct buffer_head *bh);
+void btrfsic_submit_bio(int rw, struct bio *bio);
+#else
+#define btrfsic_submit_bh submit_bh
+#define btrfsic_submit_bio submit_bio
+#endif
+
+int btrfsic_mount(struct btrfs_root *root,
+		  struct btrfs_fs_devices *fs_devices,
+		  int including_extent_data, u32 print_mask);
+void btrfsic_unmount(struct btrfs_root *root,
+		     struct btrfs_fs_devices *fs_devices);
+
+#endif
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index dede441bdee..0639a555e16 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -240,7 +240,7 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
 
 	cow = btrfs_alloc_free_block(trans, root, buf->len, 0,
 				     new_root_objectid, &disk_key, level,
-				     buf->start, 0);
+				     buf->start, 0, 1);
 	if (IS_ERR(cow))
 		return PTR_ERR(cow);
 
@@ -261,9 +261,9 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
 
 	WARN_ON(btrfs_header_generation(buf) > trans->transid);
 	if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
-		ret = btrfs_inc_ref(trans, root, cow, 1);
+		ret = btrfs_inc_ref(trans, root, cow, 1, 1);
 	else
-		ret = btrfs_inc_ref(trans, root, cow, 0);
+		ret = btrfs_inc_ref(trans, root, cow, 0, 1);
 
 	if (ret)
 		return ret;
@@ -350,14 +350,14 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
 		if ((owner == root->root_key.objectid ||
 		     root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
 		    !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
-			ret = btrfs_inc_ref(trans, root, buf, 1);
+			ret = btrfs_inc_ref(trans, root, buf, 1, 1);
 			BUG_ON(ret);
 
 			if (root->root_key.objectid ==
 			    BTRFS_TREE_RELOC_OBJECTID) {
-				ret = btrfs_dec_ref(trans, root, buf, 0);
+				ret = btrfs_dec_ref(trans, root, buf, 0, 1);
 				BUG_ON(ret);
-				ret = btrfs_inc_ref(trans, root, cow, 1);
+				ret = btrfs_inc_ref(trans, root, cow, 1, 1);
 				BUG_ON(ret);
 			}
 			new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
@@ -365,9 +365,9 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
 
 			if (root->root_key.objectid ==
 			    BTRFS_TREE_RELOC_OBJECTID)
-				ret = btrfs_inc_ref(trans, root, cow, 1);
+				ret = btrfs_inc_ref(trans, root, cow, 1, 1);
 			else
-				ret = btrfs_inc_ref(trans, root, cow, 0);
+				ret = btrfs_inc_ref(trans, root, cow, 0, 1);
 			BUG_ON(ret);
 		}
 		if (new_flags != 0) {
@@ -381,11 +381,11 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
 		if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
 			if (root->root_key.objectid ==
 			    BTRFS_TREE_RELOC_OBJECTID)
-				ret = btrfs_inc_ref(trans, root, cow, 1);
+				ret = btrfs_inc_ref(trans, root, cow, 1, 1);
 			else
-				ret = btrfs_inc_ref(trans, root, cow, 0);
+				ret = btrfs_inc_ref(trans, root, cow, 0, 1);
 			BUG_ON(ret);
-			ret = btrfs_dec_ref(trans, root, buf, 1);
+			ret = btrfs_dec_ref(trans, root, buf, 1, 1);
 			BUG_ON(ret);
 		}
 		clean_tree_block(trans, root, buf);
@@ -446,7 +446,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 
 	cow = btrfs_alloc_free_block(trans, root, buf->len, parent_start,
 				     root->root_key.objectid, &disk_key,
-				     level, search_start, empty_size);
+				     level, search_start, empty_size, 1);
 	if (IS_ERR(cow))
 		return PTR_ERR(cow);
 
@@ -484,7 +484,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 		rcu_assign_pointer(root->node, cow);
 
 		btrfs_free_tree_block(trans, root, buf, parent_start,
-				      last_ref);
+				      last_ref, 1);
 		free_extent_buffer(buf);
 		add_root_to_dirty_list(root);
 	} else {
@@ -500,7 +500,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 					      trans->transid);
 		btrfs_mark_buffer_dirty(parent);
 		btrfs_free_tree_block(trans, root, buf, parent_start,
-				      last_ref);
+				      last_ref, 1);
 	}
 	if (unlock_orig)
 		btrfs_tree_unlock(buf);
@@ -957,7 +957,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		free_extent_buffer(mid);
 
 		root_sub_used(root, mid->len);
-		btrfs_free_tree_block(trans, root, mid, 0, 1);
+		btrfs_free_tree_block(trans, root, mid, 0, 1, 0);
 		/* once for the root ptr */
 		free_extent_buffer(mid);
 		return 0;
@@ -1015,7 +1015,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 			if (wret)
 				ret = wret;
 			root_sub_used(root, right->len);
-			btrfs_free_tree_block(trans, root, right, 0, 1);
+			btrfs_free_tree_block(trans, root, right, 0, 1, 0);
 			free_extent_buffer(right);
 			right = NULL;
 		} else {
@@ -1055,7 +1055,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		if (wret)
 			ret = wret;
 		root_sub_used(root, mid->len);
-		btrfs_free_tree_block(trans, root, mid, 0, 1);
+		btrfs_free_tree_block(trans, root, mid, 0, 1, 0);
 		free_extent_buffer(mid);
 		mid = NULL;
 	} else {
@@ -2089,7 +2089,7 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans,
 
 	c = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
 				   root->root_key.objectid, &lower_key,
-				   level, root->node->start, 0);
+				   level, root->node->start, 0, 0);
 	if (IS_ERR(c))
 		return PTR_ERR(c);
 
@@ -2216,7 +2216,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
 
 	split = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
 					root->root_key.objectid,
-					&disk_key, level, c->start, 0);
+					&disk_key, level, c->start, 0, 0);
 	if (IS_ERR(split))
 		return PTR_ERR(split);
 
@@ -2970,7 +2970,7 @@ again:
 
 	right = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
 					root->root_key.objectid,
-					&disk_key, 0, l->start, 0);
+					&disk_key, 0, l->start, 0, 0);
 	if (IS_ERR(right))
 		return PTR_ERR(right);
 
@@ -3781,7 +3781,7 @@ static noinline int btrfs_del_leaf(struct btrfs_trans_handle *trans,
 
 	root_sub_used(root, leaf->len);
 
-	btrfs_free_tree_block(trans, root, leaf, 0, 1);
+	btrfs_free_tree_block(trans, root, leaf, 0, 1, 0);
 	return 0;
 }
 /*
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 67385033323..27ebe61d3cc 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -86,6 +86,9 @@ struct btrfs_ordered_sum;
 /* holds checksums of all the data extents */
 #define BTRFS_CSUM_TREE_OBJECTID 7ULL
 
+/* for storing balance parameters in the root tree */
+#define BTRFS_BALANCE_OBJECTID -4ULL
+
 /* orhpan objectid for tracking unlinked/truncated files */
 #define BTRFS_ORPHAN_OBJECTID -5ULL
 
@@ -692,6 +695,54 @@ struct btrfs_root_ref {
 	__le16 name_len;
 } __attribute__ ((__packed__));
 
+struct btrfs_disk_balance_args {
+	/*
+	 * profiles to operate on, single is denoted by
+	 * BTRFS_AVAIL_ALLOC_BIT_SINGLE
+	 */
+	__le64 profiles;
+
+	/* usage filter */
+	__le64 usage;
+
+	/* devid filter */
+	__le64 devid;
+
+	/* devid subset filter [pstart..pend) */
+	__le64 pstart;
+	__le64 pend;
+
+	/* btrfs virtual address space subset filter [vstart..vend) */
+	__le64 vstart;
+	__le64 vend;
+
+	/*
+	 * profile to convert to, single is denoted by
+	 * BTRFS_AVAIL_ALLOC_BIT_SINGLE
+	 */
+	__le64 target;
+
+	/* BTRFS_BALANCE_ARGS_* */
+	__le64 flags;
+
+	__le64 unused[8];
+} __attribute__ ((__packed__));
+
+/*
+ * store balance parameters to disk so that balance can be properly
+ * resumed after crash or unmount
+ */
+struct btrfs_balance_item {
+	/* BTRFS_BALANCE_* */
+	__le64 flags;
+
+	struct btrfs_disk_balance_args data;
+	struct btrfs_disk_balance_args meta;
+	struct btrfs_disk_balance_args sys;
+
+	__le64 unused[4];
+} __attribute__ ((__packed__));
+
 #define BTRFS_FILE_EXTENT_INLINE 0
 #define BTRFS_FILE_EXTENT_REG 1
 #define BTRFS_FILE_EXTENT_PREALLOC 2
@@ -751,14 +802,32 @@ struct btrfs_csum_item {
 } __attribute__ ((__packed__));
 
 /* different types of block groups (and chunks) */
-#define BTRFS_BLOCK_GROUP_DATA     (1 << 0)
-#define BTRFS_BLOCK_GROUP_SYSTEM   (1 << 1)
-#define BTRFS_BLOCK_GROUP_METADATA (1 << 2)
-#define BTRFS_BLOCK_GROUP_RAID0    (1 << 3)
-#define BTRFS_BLOCK_GROUP_RAID1    (1 << 4)
-#define BTRFS_BLOCK_GROUP_DUP	   (1 << 5)
-#define BTRFS_BLOCK_GROUP_RAID10   (1 << 6)
-#define BTRFS_NR_RAID_TYPES	   5
+#define BTRFS_BLOCK_GROUP_DATA		(1ULL << 0)
+#define BTRFS_BLOCK_GROUP_SYSTEM	(1ULL << 1)
+#define BTRFS_BLOCK_GROUP_METADATA	(1ULL << 2)
+#define BTRFS_BLOCK_GROUP_RAID0		(1ULL << 3)
+#define BTRFS_BLOCK_GROUP_RAID1		(1ULL << 4)
+#define BTRFS_BLOCK_GROUP_DUP		(1ULL << 5)
+#define BTRFS_BLOCK_GROUP_RAID10	(1ULL << 6)
+#define BTRFS_BLOCK_GROUP_RESERVED	BTRFS_AVAIL_ALLOC_BIT_SINGLE
+#define BTRFS_NR_RAID_TYPES		5
+
+#define BTRFS_BLOCK_GROUP_TYPE_MASK	(BTRFS_BLOCK_GROUP_DATA |    \
+					 BTRFS_BLOCK_GROUP_SYSTEM |  \
+					 BTRFS_BLOCK_GROUP_METADATA)
+
+#define BTRFS_BLOCK_GROUP_PROFILE_MASK	(BTRFS_BLOCK_GROUP_RAID0 |   \
+					 BTRFS_BLOCK_GROUP_RAID1 |   \
+					 BTRFS_BLOCK_GROUP_DUP |     \
+					 BTRFS_BLOCK_GROUP_RAID10)
+/*
+ * We need a bit for restriper to be able to tell when chunks of type
+ * SINGLE are available.  This "extended" profile format is used in
+ * fs_info->avail_*_alloc_bits (in-memory) and balance item fields
+ * (on-disk).  The corresponding on-disk bit in chunk.type is reserved
+ * to avoid remappings between two formats in future.
+ */
+#define BTRFS_AVAIL_ALLOC_BIT_SINGLE	(1ULL << 48)
 
 struct btrfs_block_group_item {
 	__le64 used;
@@ -916,6 +985,7 @@ struct btrfs_block_group_cache {
 struct reloc_control;
 struct btrfs_device;
 struct btrfs_fs_devices;
+struct btrfs_balance_control;
 struct btrfs_delayed_root;
 struct btrfs_fs_info {
 	u8 fsid[BTRFS_FSID_SIZE];
@@ -971,7 +1041,7 @@ struct btrfs_fs_info {
 	 * is required instead of the faster short fsync log commits
 	 */
 	u64 last_trans_log_full_commit;
-	unsigned long mount_opt:20;
+	unsigned long mount_opt:21;
 	unsigned long compress_type:4;
 	u64 max_inline;
 	u64 alloc_start;
@@ -1132,12 +1202,23 @@ struct btrfs_fs_info {
 	spinlock_t ref_cache_lock;
 	u64 total_ref_cache_size;
 
+	/*
+	 * these three are in extended format (availability of single
+	 * chunks is denoted by BTRFS_AVAIL_ALLOC_BIT_SINGLE bit, other
+	 * types are denoted by corresponding BTRFS_BLOCK_GROUP_* bits)
+	 */
 	u64 avail_data_alloc_bits;
 	u64 avail_metadata_alloc_bits;
 	u64 avail_system_alloc_bits;
-	u64 data_alloc_profile;
-	u64 metadata_alloc_profile;
-	u64 system_alloc_profile;
+
+	/* restriper state */
+	spinlock_t balance_lock;
+	struct mutex balance_mutex;
+	atomic_t balance_running;
+	atomic_t balance_pause_req;
+	atomic_t balance_cancel_req;
+	struct btrfs_balance_control *balance_ctl;
+	wait_queue_head_t balance_wait_q;
 
 	unsigned data_chunk_allocations;
 	unsigned metadata_ratio;
@@ -1155,6 +1236,10 @@ struct btrfs_fs_info {
 	int scrub_workers_refcnt;
 	struct btrfs_workers scrub_workers;
 
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+	u32 check_integrity_print_mask;
+#endif
+
 	/* filesystem state */
 	u64 fs_state;
 
@@ -1383,6 +1468,8 @@ struct btrfs_ioctl_defrag_range_args {
 #define BTRFS_DEV_ITEM_KEY	216
 #define BTRFS_CHUNK_ITEM_KEY	228
 
+#define BTRFS_BALANCE_ITEM_KEY	248
+
 /*
  * string items are for debugging.  They just store a short string of
  * data in the FS
@@ -1413,6 +1500,9 @@ struct btrfs_ioctl_defrag_range_args {
 #define BTRFS_MOUNT_AUTO_DEFRAG		(1 << 16)
 #define BTRFS_MOUNT_INODE_MAP_CACHE	(1 << 17)
 #define BTRFS_MOUNT_RECOVERY		(1 << 18)
+#define BTRFS_MOUNT_SKIP_BALANCE	(1 << 19)
+#define BTRFS_MOUNT_CHECK_INTEGRITY	(1 << 20)
+#define BTRFS_MOUNT_CHECK_INTEGRITY_INCLUDING_EXTENT_DATA (1 << 21)
 
 #define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)
 #define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)
@@ -2077,8 +2167,86 @@ BTRFS_SETGET_STACK_FUNCS(backup_bytes_used, struct btrfs_root_backup,
 BTRFS_SETGET_STACK_FUNCS(backup_num_devices, struct btrfs_root_backup,
 		   num_devices, 64);
 
-/* struct btrfs_super_block */
+/* struct btrfs_balance_item */
+BTRFS_SETGET_FUNCS(balance_flags, struct btrfs_balance_item, flags, 64);
 
+static inline void btrfs_balance_data(struct extent_buffer *eb,
+				      struct btrfs_balance_item *bi,
+				      struct btrfs_disk_balance_args *ba)
+{
+	read_eb_member(eb, bi, struct btrfs_balance_item, data, ba);
+}
+
+static inline void btrfs_set_balance_data(struct extent_buffer *eb,
+					  struct btrfs_balance_item *bi,
+					  struct btrfs_disk_balance_args *ba)
+{
+	write_eb_member(eb, bi, struct btrfs_balance_item, data, ba);
+}
+
+static inline void btrfs_balance_meta(struct extent_buffer *eb,
+				      struct btrfs_balance_item *bi,
+				      struct btrfs_disk_balance_args *ba)
+{
+	read_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);
+}
+
+static inline void btrfs_set_balance_meta(struct extent_buffer *eb,
+					  struct btrfs_balance_item *bi,
+					  struct btrfs_disk_balance_args *ba)
+{
+	write_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);
+}
+
+static inline void btrfs_balance_sys(struct extent_buffer *eb,
+				     struct btrfs_balance_item *bi,
+				     struct btrfs_disk_balance_args *ba)
+{
+	read_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);
+}
+
+static inline void btrfs_set_balance_sys(struct extent_buffer *eb,
+					 struct btrfs_balance_item *bi,
+					 struct btrfs_disk_balance_args *ba)
+{
+	write_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);
+}
+
+static inline void
+btrfs_disk_balance_args_to_cpu(struct btrfs_balance_args *cpu,
+			       struct btrfs_disk_balance_args *disk)
+{
+	memset(cpu, 0, sizeof(*cpu));
+
+	cpu->profiles = le64_to_cpu(disk->profiles);
+	cpu->usage = le64_to_cpu(disk->usage);
+	cpu->devid = le64_to_cpu(disk->devid);
+	cpu->pstart = le64_to_cpu(disk->pstart);
+	cpu->pend = le64_to_cpu(disk->pend);
+	cpu->vstart = le64_to_cpu(disk->vstart);
+	cpu->vend = le64_to_cpu(disk->vend);
+	cpu->target = le64_to_cpu(disk->target);
+	cpu->flags = le64_to_cpu(disk->flags);
+}
+
+static inline void
+btrfs_cpu_balance_args_to_disk(struct btrfs_disk_balance_args *disk,
+			       struct btrfs_balance_args *cpu)
+{
+	memset(disk, 0, sizeof(*disk));
+
+	disk->profiles = cpu_to_le64(cpu->profiles);
+	disk->usage = cpu_to_le64(cpu->usage);
+	disk->devid = cpu_to_le64(cpu->devid);
+	disk->pstart = cpu_to_le64(cpu->pstart);
+	disk->pend = cpu_to_le64(cpu->pend);
+	disk->vstart = cpu_to_le64(cpu->vstart);
+	disk->vend = cpu_to_le64(cpu->vend);
+	disk->target = cpu_to_le64(cpu->target);
+	disk->flags = cpu_to_le64(cpu->flags);
+}
+
+/* struct btrfs_super_block */
 BTRFS_SETGET_STACK_FUNCS(super_bytenr, struct btrfs_super_block, bytenr, 64);
 BTRFS_SETGET_STACK_FUNCS(super_flags, struct btrfs_super_block, flags, 64);
 BTRFS_SETGET_STACK_FUNCS(super_generation, struct btrfs_super_block,
@@ -2196,7 +2364,7 @@ static inline u32 btrfs_file_extent_inline_item_len(struct extent_buffer *eb,
 	return btrfs_item_size(eb, e) - offset;
 }
 
-static inline struct btrfs_root *btrfs_sb(struct super_block *sb)
+static inline struct btrfs_fs_info *btrfs_sb(struct super_block *sb)
 {
 	return sb->s_fs_info;
 }
@@ -2277,11 +2445,11 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 					struct btrfs_root *root, u32 blocksize,
 					u64 parent, u64 root_objectid,
 					struct btrfs_disk_key *key, int level,
-					u64 hint, u64 empty_size);
+					u64 hint, u64 empty_size, int for_cow);
 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
 			   struct btrfs_root *root,
 			   struct extent_buffer *buf,
-			   u64 parent, int last_ref);
+			   u64 parent, int last_ref, int for_cow);
 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
 					    struct btrfs_root *root,
 					    u64 bytenr, u32 blocksize,
@@ -2301,17 +2469,17 @@ int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
 				  u64 search_end, struct btrfs_key *ins,
 				  u64 data);
 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
-		  struct extent_buffer *buf, int full_backref);
+		  struct extent_buffer *buf, int full_backref, int for_cow);
 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
-		  struct extent_buffer *buf, int full_backref);
+		  struct extent_buffer *buf, int full_backref, int for_cow);
 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
 				struct btrfs_root *root,
 				u64 bytenr, u64 num_bytes, u64 flags,
 				int is_data);
 int btrfs_free_extent(struct btrfs_trans_handle *trans,
 		      struct btrfs_root *root,
-		      u64 bytenr, u64 num_bytes, u64 parent,
-		      u64 root_objectid, u64 owner, u64 offset);
+		      u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
+		      u64 owner, u64 offset, int for_cow);
 
 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len);
 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
@@ -2323,7 +2491,7 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 			 struct btrfs_root *root,
 			 u64 bytenr, u64 num_bytes, u64 parent,
-			 u64 root_objectid, u64 owner, u64 offset);
+			 u64 root_objectid, u64 owner, u64 offset, int for_cow);
 
 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
 				    struct btrfs_root *root);
@@ -2482,10 +2650,18 @@ static inline int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
 }
 
 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
+static inline int btrfs_next_item(struct btrfs_root *root, struct btrfs_path *p)
+{
+	++p->slots[0];
+	if (p->slots[0] >= btrfs_header_nritems(p->nodes[0]))
+		return btrfs_next_leaf(root, p);
+	return 0;
+}
 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path);
 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf);
 void btrfs_drop_snapshot(struct btrfs_root *root,
-			 struct btrfs_block_rsv *block_rsv, int update_ref);
+			 struct btrfs_block_rsv *block_rsv, int update_ref,
+			 int for_reloc);
 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
 			struct btrfs_root *root,
 			struct extent_buffer *node,
@@ -2500,6 +2676,7 @@ static inline int btrfs_fs_closing(struct btrfs_fs_info *fs_info)
 }
 static inline void free_fs_info(struct btrfs_fs_info *fs_info)
 {
+	kfree(fs_info->balance_ctl);
 	kfree(fs_info->delayed_root);
 	kfree(fs_info->extent_root);
 	kfree(fs_info->tree_root);
@@ -2510,6 +2687,24 @@ static inline void free_fs_info(struct btrfs_fs_info *fs_info)
 	kfree(fs_info->super_for_commit);
 	kfree(fs_info);
 }
+/**
+ * profile_is_valid - tests whether a given profile is valid and reduced
+ * @flags: profile to validate
+ * @extended: if true @flags is treated as an extended profile
+ */
+static inline int profile_is_valid(u64 flags, int extended)
+{
+	u64 mask = ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
+
+	flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
+	if (extended)
+		mask &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+
+	if (flags & mask)
+		return 0;
+	/* true if zero or exactly one bit set */
+	return (flags & (~flags + 1)) == flags;
+}
 
 /* root-item.c */
 int btrfs_find_root_ref(struct btrfs_root *tree_root,
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 9c1eccc2c50..fe4cd0f1cef 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -595,8 +595,12 @@ static int btrfs_delayed_item_reserve_metadata(struct btrfs_trans_handle *trans,
 
 	num_bytes = btrfs_calc_trans_metadata_size(root, 1);
 	ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes);
-	if (!ret)
+	if (!ret) {
+		trace_btrfs_space_reservation(root->fs_info, "delayed_item",
+					      item->key.objectid,
+					      num_bytes, 1);
 		item->bytes_reserved = num_bytes;
+	}
 
 	return ret;
 }
@@ -610,6 +614,9 @@ static void btrfs_delayed_item_release_metadata(struct btrfs_root *root,
 		return;
 
 	rsv = &root->fs_info->delayed_block_rsv;
+	trace_btrfs_space_reservation(root->fs_info, "delayed_item",
+				      item->key.objectid, item->bytes_reserved,
+				      0);
 	btrfs_block_rsv_release(root, rsv,
 				item->bytes_reserved);
 }
@@ -624,7 +631,7 @@ static int btrfs_delayed_inode_reserve_metadata(
 	struct btrfs_block_rsv *dst_rsv;
 	u64 num_bytes;
 	int ret;
-	int release = false;
+	bool release = false;
 
 	src_rsv = trans->block_rsv;
 	dst_rsv = &root->fs_info->delayed_block_rsv;
@@ -651,8 +658,13 @@ static int btrfs_delayed_inode_reserve_metadata(
 		 */
 		if (ret == -EAGAIN)
 			ret = -ENOSPC;
-		if (!ret)
+		if (!ret) {
 			node->bytes_reserved = num_bytes;
+			trace_btrfs_space_reservation(root->fs_info,
+						      "delayed_inode",
+						      btrfs_ino(inode),
+						      num_bytes, 1);
+		}
 		return ret;
 	} else if (src_rsv == &root->fs_info->delalloc_block_rsv) {
 		spin_lock(&BTRFS_I(inode)->lock);
@@ -707,11 +719,17 @@ out:
 	 * reservation here.  I think it may be time for a documentation page on
 	 * how block rsvs. work.
 	 */
-	if (!ret)
+	if (!ret) {
+		trace_btrfs_space_reservation(root->fs_info, "delayed_inode",
+					      btrfs_ino(inode), num_bytes, 1);
 		node->bytes_reserved = num_bytes;
+	}
 
-	if (release)
+	if (release) {
+		trace_btrfs_space_reservation(root->fs_info, "delalloc",
+					      btrfs_ino(inode), num_bytes, 0);
 		btrfs_block_rsv_release(root, src_rsv, num_bytes);
+	}
 
 	return ret;
 }
@@ -725,6 +743,8 @@ static void btrfs_delayed_inode_release_metadata(struct btrfs_root *root,
 		return;
 
 	rsv = &root->fs_info->delayed_block_rsv;
+	trace_btrfs_space_reservation(root->fs_info, "delayed_inode",
+				      node->inode_id, node->bytes_reserved, 0);
 	btrfs_block_rsv_release(root, rsv,
 				node->bytes_reserved);
 	node->bytes_reserved = 0;
@@ -1372,13 +1392,6 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
 		goto release_node;
 	}
 
-	ret = btrfs_delayed_item_reserve_metadata(trans, root, delayed_item);
-	/*
-	 * we have reserved enough space when we start a new transaction,
-	 * so reserving metadata failure is impossible
-	 */
-	BUG_ON(ret);
-
 	delayed_item->key.objectid = btrfs_ino(dir);
 	btrfs_set_key_type(&delayed_item->key, BTRFS_DIR_INDEX_KEY);
 	delayed_item->key.offset = index;
@@ -1391,6 +1404,14 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans,
 	dir_item->type = type;
 	memcpy((char *)(dir_item + 1), name, name_len);
 
+	ret = btrfs_delayed_item_reserve_metadata(trans, root, delayed_item);
+	/*
+	 * we have reserved enough space when we start a new transaction,
+	 * so reserving metadata failure is impossible
+	 */
+	BUG_ON(ret);
+
+
 	mutex_lock(&delayed_node->mutex);
 	ret = __btrfs_add_delayed_insertion_item(delayed_node, delayed_item);
 	if (unlikely(ret)) {
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 125cf76fcd0..66e4f29505a 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -101,6 +101,11 @@ static int comp_entry(struct btrfs_delayed_ref_node *ref2,
 		return -1;
 	if (ref1->type > ref2->type)
 		return 1;
+	/* merging of sequenced refs is not allowed */
+	if (ref1->seq < ref2->seq)
+		return -1;
+	if (ref1->seq > ref2->seq)
+		return 1;
 	if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
 	    ref1->type == BTRFS_SHARED_BLOCK_REF_KEY) {
 		return comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref2),
@@ -150,16 +155,22 @@ static struct btrfs_delayed_ref_node *tree_insert(struct rb_root *root,
 
 /*
  * find an head entry based on bytenr. This returns the delayed ref
- * head if it was able to find one, or NULL if nothing was in that spot
+ * head if it was able to find one, or NULL if nothing was in that spot.
+ * If return_bigger is given, the next bigger entry is returned if no exact
+ * match is found.
  */
 static struct btrfs_delayed_ref_node *find_ref_head(struct rb_root *root,
 				  u64 bytenr,
-				  struct btrfs_delayed_ref_node **last)
+				  struct btrfs_delayed_ref_node **last,
+				  int return_bigger)
 {
-	struct rb_node *n = root->rb_node;
+	struct rb_node *n;
 	struct btrfs_delayed_ref_node *entry;
-	int cmp;
+	int cmp = 0;
 
+again:
+	n = root->rb_node;
+	entry = NULL;
 	while (n) {
 		entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
 		WARN_ON(!entry->in_tree);
@@ -182,6 +193,19 @@ static struct btrfs_delayed_ref_node *find_ref_head(struct rb_root *root,
 		else
 			return entry;
 	}
+	if (entry && return_bigger) {
+		if (cmp > 0) {
+			n = rb_next(&entry->rb_node);
+			if (!n)
+				n = rb_first(root);
+			entry = rb_entry(n, struct btrfs_delayed_ref_node,
+					 rb_node);
+			bytenr = entry->bytenr;
+			return_bigger = 0;
+			goto again;
+		}
+		return entry;
+	}
 	return NULL;
 }
 
@@ -209,6 +233,24 @@ int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
 	return 0;
 }
 
+int btrfs_check_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
+			    u64 seq)
+{
+	struct seq_list *elem;
+
+	assert_spin_locked(&delayed_refs->lock);
+	if (list_empty(&delayed_refs->seq_head))
+		return 0;
+
+	elem = list_first_entry(&delayed_refs->seq_head, struct seq_list, list);
+	if (seq >= elem->seq) {
+		pr_debug("holding back delayed_ref %llu, lowest is %llu (%p)\n",
+			 seq, elem->seq, delayed_refs);
+		return 1;
+	}
+	return 0;
+}
+
 int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
 			   struct list_head *cluster, u64 start)
 {
@@ -223,20 +265,8 @@ int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
 		node = rb_first(&delayed_refs->root);
 	} else {
 		ref = NULL;
-		find_ref_head(&delayed_refs->root, start, &ref);
+		find_ref_head(&delayed_refs->root, start + 1, &ref, 1);
 		if (ref) {
-			struct btrfs_delayed_ref_node *tmp;
-
-			node = rb_prev(&ref->rb_node);
-			while (node) {
-				tmp = rb_entry(node,
-					       struct btrfs_delayed_ref_node,
-					       rb_node);
-				if (tmp->bytenr < start)
-					break;
-				ref = tmp;
-				node = rb_prev(&ref->rb_node);
-			}
 			node = &ref->rb_node;
 		} else
 			node = rb_first(&delayed_refs->root);
@@ -390,7 +420,8 @@ update_existing_head_ref(struct btrfs_delayed_ref_node *existing,
  * this does all the dirty work in terms of maintaining the correct
  * overall modification count.
  */
-static noinline int add_delayed_ref_head(struct btrfs_trans_handle *trans,
+static noinline int add_delayed_ref_head(struct btrfs_fs_info *fs_info,
+					struct btrfs_trans_handle *trans,
 					struct btrfs_delayed_ref_node *ref,
 					u64 bytenr, u64 num_bytes,
 					int action, int is_data)
@@ -437,6 +468,7 @@ static noinline int add_delayed_ref_head(struct btrfs_trans_handle *trans,
 	ref->action  = 0;
 	ref->is_head = 1;
 	ref->in_tree = 1;
+	ref->seq = 0;
 
 	head_ref = btrfs_delayed_node_to_head(ref);
 	head_ref->must_insert_reserved = must_insert_reserved;
@@ -468,14 +500,17 @@ static noinline int add_delayed_ref_head(struct btrfs_trans_handle *trans,
 /*
  * helper to insert a delayed tree ref into the rbtree.
  */
-static noinline int add_delayed_tree_ref(struct btrfs_trans_handle *trans,
+static noinline int add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
+					 struct btrfs_trans_handle *trans,
 					 struct btrfs_delayed_ref_node *ref,
 					 u64 bytenr, u64 num_bytes, u64 parent,
-					 u64 ref_root, int level, int action)
+					 u64 ref_root, int level, int action,
+					 int for_cow)
 {
 	struct btrfs_delayed_ref_node *existing;
 	struct btrfs_delayed_tree_ref *full_ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
+	u64 seq = 0;
 
 	if (action == BTRFS_ADD_DELAYED_EXTENT)
 		action = BTRFS_ADD_DELAYED_REF;
@@ -491,14 +526,17 @@ static noinline int add_delayed_tree_ref(struct btrfs_trans_handle *trans,
 	ref->is_head = 0;
 	ref->in_tree = 1;
 
+	if (need_ref_seq(for_cow, ref_root))
+		seq = inc_delayed_seq(delayed_refs);
+	ref->seq = seq;
+
 	full_ref = btrfs_delayed_node_to_tree_ref(ref);
-	if (parent) {
-		full_ref->parent = parent;
+	full_ref->parent = parent;
+	full_ref->root = ref_root;
+	if (parent)
 		ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
-	} else {
-		full_ref->root = ref_root;
+	else
 		ref->type = BTRFS_TREE_BLOCK_REF_KEY;
-	}
 	full_ref->level = level;
 
 	trace_btrfs_delayed_tree_ref(ref, full_ref, action);
@@ -522,15 +560,17 @@ static noinline int add_delayed_tree_ref(struct btrfs_trans_handle *trans,
 /*
  * helper to insert a delayed data ref into the rbtree.
  */
-static noinline int add_delayed_data_ref(struct btrfs_trans_handle *trans,
+static noinline int add_delayed_data_ref(struct btrfs_fs_info *fs_info,
+					 struct btrfs_trans_handle *trans,
 					 struct btrfs_delayed_ref_node *ref,
 					 u64 bytenr, u64 num_bytes, u64 parent,
 					 u64 ref_root, u64 owner, u64 offset,
-					 int action)
+					 int action, int for_cow)
 {
 	struct btrfs_delayed_ref_node *existing;
 	struct btrfs_delayed_data_ref *full_ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
+	u64 seq = 0;
 
 	if (action == BTRFS_ADD_DELAYED_EXTENT)
 		action = BTRFS_ADD_DELAYED_REF;
@@ -546,14 +586,18 @@ static noinline int add_delayed_data_ref(struct btrfs_trans_handle *trans,
 	ref->is_head = 0;
 	ref->in_tree = 1;
 
+	if (need_ref_seq(for_cow, ref_root))
+		seq = inc_delayed_seq(delayed_refs);
+	ref->seq = seq;
+
 	full_ref = btrfs_delayed_node_to_data_ref(ref);
-	if (parent) {
-		full_ref->parent = parent;
+	full_ref->parent = parent;
+	full_ref->root = ref_root;
+	if (parent)
 		ref->type = BTRFS_SHARED_DATA_REF_KEY;
-	} else {
-		full_ref->root = ref_root;
+	else
 		ref->type = BTRFS_EXTENT_DATA_REF_KEY;
-	}
+
 	full_ref->objectid = owner;
 	full_ref->offset = offset;
 
@@ -580,10 +624,12 @@ static noinline int add_delayed_data_ref(struct btrfs_trans_handle *trans,
  * to make sure the delayed ref is eventually processed before this
  * transaction commits.
  */
-int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
+int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
+			       struct btrfs_trans_handle *trans,
 			       u64 bytenr, u64 num_bytes, u64 parent,
 			       u64 ref_root,  int level, int action,
-			       struct btrfs_delayed_extent_op *extent_op)
+			       struct btrfs_delayed_extent_op *extent_op,
+			       int for_cow)
 {
 	struct btrfs_delayed_tree_ref *ref;
 	struct btrfs_delayed_ref_head *head_ref;
@@ -610,13 +656,17 @@ int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
 	 * insert both the head node and the new ref without dropping
 	 * the spin lock
 	 */
-	ret = add_delayed_ref_head(trans, &head_ref->node, bytenr, num_bytes,
-				   action, 0);
+	ret = add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
+				   num_bytes, action, 0);
 	BUG_ON(ret);
 
-	ret = add_delayed_tree_ref(trans, &ref->node, bytenr, num_bytes,
-				   parent, ref_root, level, action);
+	ret = add_delayed_tree_ref(fs_info, trans, &ref->node, bytenr,
+				   num_bytes, parent, ref_root, level, action,
+				   for_cow);
 	BUG_ON(ret);
+	if (!need_ref_seq(for_cow, ref_root) &&
+	    waitqueue_active(&delayed_refs->seq_wait))
+		wake_up(&delayed_refs->seq_wait);
 	spin_unlock(&delayed_refs->lock);
 	return 0;
 }
@@ -624,11 +674,13 @@ int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
 /*
  * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
  */
-int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
+int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
+			       struct btrfs_trans_handle *trans,
 			       u64 bytenr, u64 num_bytes,
 			       u64 parent, u64 ref_root,
 			       u64 owner, u64 offset, int action,
-			       struct btrfs_delayed_extent_op *extent_op)
+			       struct btrfs_delayed_extent_op *extent_op,
+			       int for_cow)
 {
 	struct btrfs_delayed_data_ref *ref;
 	struct btrfs_delayed_ref_head *head_ref;
@@ -655,18 +707,23 @@ int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
 	 * insert both the head node and the new ref without dropping
 	 * the spin lock
 	 */
-	ret = add_delayed_ref_head(trans, &head_ref->node, bytenr, num_bytes,
-				   action, 1);
+	ret = add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
+				   num_bytes, action, 1);
 	BUG_ON(ret);
 
-	ret = add_delayed_data_ref(trans, &ref->node, bytenr, num_bytes,
-				   parent, ref_root, owner, offset, action);
+	ret = add_delayed_data_ref(fs_info, trans, &ref->node, bytenr,
+				   num_bytes, parent, ref_root, owner, offset,
+				   action, for_cow);
 	BUG_ON(ret);
+	if (!need_ref_seq(for_cow, ref_root) &&
+	    waitqueue_active(&delayed_refs->seq_wait))
+		wake_up(&delayed_refs->seq_wait);
 	spin_unlock(&delayed_refs->lock);
 	return 0;
 }
 
-int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
+int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
+				struct btrfs_trans_handle *trans,
 				u64 bytenr, u64 num_bytes,
 				struct btrfs_delayed_extent_op *extent_op)
 {
@@ -683,11 +740,13 @@ int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
 	delayed_refs = &trans->transaction->delayed_refs;
 	spin_lock(&delayed_refs->lock);
 
-	ret = add_delayed_ref_head(trans, &head_ref->node, bytenr,
+	ret = add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
 				   num_bytes, BTRFS_UPDATE_DELAYED_HEAD,
 				   extent_op->is_data);
 	BUG_ON(ret);
 
+	if (waitqueue_active(&delayed_refs->seq_wait))
+		wake_up(&delayed_refs->seq_wait);
 	spin_unlock(&delayed_refs->lock);
 	return 0;
 }
@@ -704,7 +763,7 @@ btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr)
 	struct btrfs_delayed_ref_root *delayed_refs;
 
 	delayed_refs = &trans->transaction->delayed_refs;
-	ref = find_ref_head(&delayed_refs->root, bytenr, NULL);
+	ref = find_ref_head(&delayed_refs->root, bytenr, NULL, 0);
 	if (ref)
 		return btrfs_delayed_node_to_head(ref);
 	return NULL;
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index e287e3b0eab..d8f244d9492 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -33,6 +33,9 @@ struct btrfs_delayed_ref_node {
 	/* the size of the extent */
 	u64 num_bytes;
 
+	/* seq number to keep track of insertion order */
+	u64 seq;
+
 	/* ref count on this data structure */
 	atomic_t refs;
 
@@ -98,19 +101,15 @@ struct btrfs_delayed_ref_head {
 
 struct btrfs_delayed_tree_ref {
 	struct btrfs_delayed_ref_node node;
-	union {
-		u64 root;
-		u64 parent;
-	};
+	u64 root;
+	u64 parent;
 	int level;
 };
 
 struct btrfs_delayed_data_ref {
 	struct btrfs_delayed_ref_node node;
-	union {
-		u64 root;
-		u64 parent;
-	};
+	u64 root;
+	u64 parent;
 	u64 objectid;
 	u64 offset;
 };
@@ -140,6 +139,26 @@ struct btrfs_delayed_ref_root {
 	int flushing;
 
 	u64 run_delayed_start;
+
+	/*
+	 * seq number of delayed refs. We need to know if a backref was being
+	 * added before the currently processed ref or afterwards.
+	 */
+	u64 seq;
+
+	/*
+	 * seq_list holds a list of all seq numbers that are currently being
+	 * added to the list. While walking backrefs (btrfs_find_all_roots,
+	 * qgroups), which might take some time, no newer ref must be processed,
+	 * as it might influence the outcome of the walk.
+	 */
+	struct list_head seq_head;
+
+	/*
+	 * when the only refs we have in the list must not be processed, we want
+	 * to wait for more refs to show up or for the end of backref walking.
+	 */
+	wait_queue_head_t seq_wait;
 };
 
 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
@@ -151,16 +170,21 @@ static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
 	}
 }
 
-int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
+int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
+			       struct btrfs_trans_handle *trans,
 			       u64 bytenr, u64 num_bytes, u64 parent,
 			       u64 ref_root, int level, int action,
-			       struct btrfs_delayed_extent_op *extent_op);
-int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
+			       struct btrfs_delayed_extent_op *extent_op,
+			       int for_cow);
+int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
+			       struct btrfs_trans_handle *trans,
 			       u64 bytenr, u64 num_bytes,
 			       u64 parent, u64 ref_root,
 			       u64 owner, u64 offset, int action,
-			       struct btrfs_delayed_extent_op *extent_op);
-int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
+			       struct btrfs_delayed_extent_op *extent_op,
+			       int for_cow);
+int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
+				struct btrfs_trans_handle *trans,
 				u64 bytenr, u64 num_bytes,
 				struct btrfs_delayed_extent_op *extent_op);
 
@@ -170,6 +194,60 @@ int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
 			   struct btrfs_delayed_ref_head *head);
 int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
 			   struct list_head *cluster, u64 search_start);
+
+struct seq_list {
+	struct list_head list;
+	u64 seq;
+};
+
+static inline u64 inc_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs)
+{
+	assert_spin_locked(&delayed_refs->lock);
+	++delayed_refs->seq;
+	return delayed_refs->seq;
+}
+
+static inline void
+btrfs_get_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
+		      struct seq_list *elem)
+{
+	assert_spin_locked(&delayed_refs->lock);
+	elem->seq = delayed_refs->seq;
+	list_add_tail(&elem->list, &delayed_refs->seq_head);
+}
+
+static inline void
+btrfs_put_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
+		      struct seq_list *elem)
+{
+	spin_lock(&delayed_refs->lock);
+	list_del(&elem->list);
+	wake_up(&delayed_refs->seq_wait);
+	spin_unlock(&delayed_refs->lock);
+}
+
+int btrfs_check_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
+			    u64 seq);
+
+/*
+ * delayed refs with a ref_seq > 0 must be held back during backref walking.
+ * this only applies to items in one of the fs-trees. for_cow items never need
+ * to be held back, so they won't get a ref_seq number.
+ */
+static inline int need_ref_seq(int for_cow, u64 rootid)
+{
+	if (for_cow)
+		return 0;
+
+	if (rootid == BTRFS_FS_TREE_OBJECTID)
+		return 1;
+
+	if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
+		return 1;
+
+	return 0;
+}
+
 /*
  * a node might live in a head or a regular ref, this lets you
  * test for the proper type to use.
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index f44b3928dc2..811d9f918b1 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -43,6 +43,7 @@
 #include "tree-log.h"
 #include "free-space-cache.h"
 #include "inode-map.h"
+#include "check-integrity.h"
 
 static struct extent_io_ops btree_extent_io_ops;
 static void end_workqueue_fn(struct btrfs_work *work);
@@ -872,7 +873,8 @@ static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 
 #ifdef CONFIG_MIGRATION
 static int btree_migratepage(struct address_space *mapping,
-			struct page *newpage, struct page *page)
+			struct page *newpage, struct page *page,
+			enum migrate_mode mode)
 {
 	/*
 	 * we can't safely write a btree page from here,
@@ -887,7 +889,7 @@ static int btree_migratepage(struct address_space *mapping,
 	if (page_has_private(page) &&
 	    !try_to_release_page(page, GFP_KERNEL))
 		return -EAGAIN;
-	return migrate_page(mapping, newpage, page);
+	return migrate_page(mapping, newpage, page, mode);
 }
 #endif
 
@@ -960,6 +962,13 @@ static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 	tree = &BTRFS_I(page->mapping->host)->io_tree;
 	map = &BTRFS_I(page->mapping->host)->extent_tree;
 
+	/*
+	 * We need to mask out eg. __GFP_HIGHMEM and __GFP_DMA32 as we're doing
+	 * slab allocation from alloc_extent_state down the callchain where
+	 * it'd hit a BUG_ON as those flags are not allowed.
+	 */
+	gfp_flags &= ~GFP_SLAB_BUG_MASK;
+
 	ret = try_release_extent_state(map, tree, page, gfp_flags);
 	if (!ret)
 		return 0;
@@ -1142,7 +1151,6 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 	root->orphan_item_inserted = 0;
 	root->orphan_cleanup_state = 0;
 
-	root->fs_info = fs_info;
 	root->objectid = objectid;
 	root->last_trans = 0;
 	root->highest_objectid = 0;
@@ -1216,6 +1224,14 @@ static int find_and_setup_root(struct btrfs_root *tree_root,
 	return 0;
 }
 
+static struct btrfs_root *btrfs_alloc_root(struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_root *root = kzalloc(sizeof(*root), GFP_NOFS);
+	if (root)
+		root->fs_info = fs_info;
+	return root;
+}
+
 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
 					 struct btrfs_fs_info *fs_info)
 {
@@ -1223,7 +1239,7 @@ static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
 	struct btrfs_root *tree_root = fs_info->tree_root;
 	struct extent_buffer *leaf;
 
-	root = kzalloc(sizeof(*root), GFP_NOFS);
+	root = btrfs_alloc_root(fs_info);
 	if (!root)
 		return ERR_PTR(-ENOMEM);
 
@@ -1243,7 +1259,8 @@ static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
 	root->ref_cows = 0;
 
 	leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
-				      BTRFS_TREE_LOG_OBJECTID, NULL, 0, 0, 0);
+				      BTRFS_TREE_LOG_OBJECTID, NULL,
+				      0, 0, 0, 0);
 	if (IS_ERR(leaf)) {
 		kfree(root);
 		return ERR_CAST(leaf);
@@ -1317,7 +1334,7 @@ struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
 	u32 blocksize;
 	int ret = 0;
 
-	root = kzalloc(sizeof(*root), GFP_NOFS);
+	root = btrfs_alloc_root(fs_info);
 	if (!root)
 		return ERR_PTR(-ENOMEM);
 	if (location->offset == (u64)-1) {
@@ -1579,9 +1596,7 @@ static int cleaner_kthread(void *arg)
 			btrfs_run_defrag_inodes(root->fs_info);
 		}
 
-		if (freezing(current)) {
-			refrigerator();
-		} else {
+		if (!try_to_freeze()) {
 			set_current_state(TASK_INTERRUPTIBLE);
 			if (!kthread_should_stop())
 				schedule();
@@ -1635,9 +1650,7 @@ sleep:
 		wake_up_process(root->fs_info->cleaner_kthread);
 		mutex_unlock(&root->fs_info->transaction_kthread_mutex);
 
-		if (freezing(current)) {
-			refrigerator();
-		} else {
+		if (!try_to_freeze()) {
 			set_current_state(TASK_INTERRUPTIBLE);
 			if (!kthread_should_stop() &&
 			    !btrfs_transaction_blocked(root->fs_info))
@@ -1877,9 +1890,9 @@ static void free_root_pointers(struct btrfs_fs_info *info, int chunk_root)
 }
 
 
-struct btrfs_root *open_ctree(struct super_block *sb,
-			      struct btrfs_fs_devices *fs_devices,
-			      char *options)
+int open_ctree(struct super_block *sb,
+	       struct btrfs_fs_devices *fs_devices,
+	       char *options)
 {
 	u32 sectorsize;
 	u32 nodesize;
@@ -1891,8 +1904,8 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	struct btrfs_key location;
 	struct buffer_head *bh;
 	struct btrfs_super_block *disk_super;
-	struct btrfs_root *tree_root = btrfs_sb(sb);
-	struct btrfs_fs_info *fs_info = tree_root->fs_info;
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	struct btrfs_root *tree_root;
 	struct btrfs_root *extent_root;
 	struct btrfs_root *csum_root;
 	struct btrfs_root *chunk_root;
@@ -1903,16 +1916,14 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	int num_backups_tried = 0;
 	int backup_index = 0;
 
-	extent_root = fs_info->extent_root =
-		kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
-	csum_root = fs_info->csum_root =
-		kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
-	chunk_root = fs_info->chunk_root =
-		kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
-	dev_root = fs_info->dev_root =
-		kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+	tree_root = fs_info->tree_root = btrfs_alloc_root(fs_info);
+	extent_root = fs_info->extent_root = btrfs_alloc_root(fs_info);
+	csum_root = fs_info->csum_root = btrfs_alloc_root(fs_info);
+	chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info);
+	dev_root = fs_info->dev_root = btrfs_alloc_root(fs_info);
 
-	if (!extent_root || !csum_root || !chunk_root || !dev_root) {
+	if (!tree_root || !extent_root || !csum_root ||
+	    !chunk_root || !dev_root) {
 		err = -ENOMEM;
 		goto fail;
 	}
@@ -2001,6 +2012,17 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	init_waitqueue_head(&fs_info->scrub_pause_wait);
 	init_rwsem(&fs_info->scrub_super_lock);
 	fs_info->scrub_workers_refcnt = 0;
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+	fs_info->check_integrity_print_mask = 0;
+#endif
+
+	spin_lock_init(&fs_info->balance_lock);
+	mutex_init(&fs_info->balance_mutex);
+	atomic_set(&fs_info->balance_running, 0);
+	atomic_set(&fs_info->balance_pause_req, 0);
+	atomic_set(&fs_info->balance_cancel_req, 0);
+	fs_info->balance_ctl = NULL;
+	init_waitqueue_head(&fs_info->balance_wait_q);
 
 	sb->s_blocksize = 4096;
 	sb->s_blocksize_bits = blksize_bits(4096);
@@ -2270,9 +2292,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	   (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
 	   BTRFS_UUID_SIZE);
 
-	mutex_lock(&fs_info->chunk_mutex);
 	ret = btrfs_read_chunk_tree(chunk_root);
-	mutex_unlock(&fs_info->chunk_mutex);
 	if (ret) {
 		printk(KERN_WARNING "btrfs: failed to read chunk tree on %s\n",
 		       sb->s_id);
@@ -2321,9 +2341,6 @@ retry_root_backup:
 
 	fs_info->generation = generation;
 	fs_info->last_trans_committed = generation;
-	fs_info->data_alloc_profile = (u64)-1;
-	fs_info->metadata_alloc_profile = (u64)-1;
-	fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
 
 	ret = btrfs_init_space_info(fs_info);
 	if (ret) {
@@ -2356,6 +2373,19 @@ retry_root_backup:
 		btrfs_set_opt(fs_info->mount_opt, SSD);
 	}
 
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+	if (btrfs_test_opt(tree_root, CHECK_INTEGRITY)) {
+		ret = btrfsic_mount(tree_root, fs_devices,
+				    btrfs_test_opt(tree_root,
+					CHECK_INTEGRITY_INCLUDING_EXTENT_DATA) ?
+				    1 : 0,
+				    fs_info->check_integrity_print_mask);
+		if (ret)
+			printk(KERN_WARNING "btrfs: failed to initialize"
+			       " integrity check module %s\n", sb->s_id);
+	}
+#endif
+
 	/* do not make disk changes in broken FS */
 	if (btrfs_super_log_root(disk_super) != 0 &&
 	    !(fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)) {
@@ -2371,7 +2401,7 @@ retry_root_backup:
 		     btrfs_level_size(tree_root,
 				      btrfs_super_log_root_level(disk_super));
 
-		log_tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+		log_tree_root = btrfs_alloc_root(fs_info);
 		if (!log_tree_root) {
 			err = -ENOMEM;
 			goto fail_trans_kthread;
@@ -2426,13 +2456,17 @@ retry_root_backup:
 		if (!err)
 			err = btrfs_orphan_cleanup(fs_info->tree_root);
 		up_read(&fs_info->cleanup_work_sem);
+
+		if (!err)
+			err = btrfs_recover_balance(fs_info->tree_root);
+
 		if (err) {
 			close_ctree(tree_root);
-			return ERR_PTR(err);
+			return err;
 		}
 	}
 
-	return tree_root;
+	return 0;
 
 fail_trans_kthread:
 	kthread_stop(fs_info->transaction_kthread);
@@ -2478,8 +2512,7 @@ fail_srcu:
 	cleanup_srcu_struct(&fs_info->subvol_srcu);
 fail:
 	btrfs_close_devices(fs_info->fs_devices);
-	free_fs_info(fs_info);
-	return ERR_PTR(err);
+	return err;
 
 recovery_tree_root:
 	if (!btrfs_test_opt(tree_root, RECOVERY))
@@ -2634,7 +2667,7 @@ static int write_dev_supers(struct btrfs_device *device,
 		 * we fua the first super.  The others we allow
 		 * to go down lazy.
 		 */
-		ret = submit_bh(WRITE_FUA, bh);
+		ret = btrfsic_submit_bh(WRITE_FUA, bh);
 		if (ret)
 			errors++;
 	}
@@ -2711,7 +2744,7 @@ static int write_dev_flush(struct btrfs_device *device, int wait)
 	device->flush_bio = bio;
 
 	bio_get(bio);
-	submit_bio(WRITE_FLUSH, bio);
+	btrfsic_submit_bio(WRITE_FLUSH, bio);
 
 	return 0;
 }
@@ -2975,6 +3008,9 @@ int close_ctree(struct btrfs_root *root)
 	fs_info->closing = 1;
 	smp_mb();
 
+	/* pause restriper - we want to resume on mount */
+	btrfs_pause_balance(root->fs_info);
+
 	btrfs_scrub_cancel(root);
 
 	/* wait for any defraggers to finish */
@@ -2982,7 +3018,7 @@ int close_ctree(struct btrfs_root *root)
 		   (atomic_read(&fs_info->defrag_running) == 0));
 
 	/* clear out the rbtree of defraggable inodes */
-	btrfs_run_defrag_inodes(root->fs_info);
+	btrfs_run_defrag_inodes(fs_info);
 
 	/*
 	 * Here come 2 situations when btrfs is broken to flip readonly:
@@ -3011,8 +3047,8 @@ int close_ctree(struct btrfs_root *root)
 
 	btrfs_put_block_group_cache(fs_info);
 
-	kthread_stop(root->fs_info->transaction_kthread);
-	kthread_stop(root->fs_info->cleaner_kthread);
+	kthread_stop(fs_info->transaction_kthread);
+	kthread_stop(fs_info->cleaner_kthread);
 
 	fs_info->closing = 2;
 	smp_mb();
@@ -3030,14 +3066,14 @@ int close_ctree(struct btrfs_root *root)
 	free_extent_buffer(fs_info->extent_root->commit_root);
 	free_extent_buffer(fs_info->tree_root->node);
 	free_extent_buffer(fs_info->tree_root->commit_root);
-	free_extent_buffer(root->fs_info->chunk_root->node);
-	free_extent_buffer(root->fs_info->chunk_root->commit_root);
-	free_extent_buffer(root->fs_info->dev_root->node);
-	free_extent_buffer(root->fs_info->dev_root->commit_root);
-	free_extent_buffer(root->fs_info->csum_root->node);
-	free_extent_buffer(root->fs_info->csum_root->commit_root);
+	free_extent_buffer(fs_info->chunk_root->node);
+	free_extent_buffer(fs_info->chunk_root->commit_root);
+	free_extent_buffer(fs_info->dev_root->node);
+	free_extent_buffer(fs_info->dev_root->commit_root);
+	free_extent_buffer(fs_info->csum_root->node);
+	free_extent_buffer(fs_info->csum_root->commit_root);
 
-	btrfs_free_block_groups(root->fs_info);
+	btrfs_free_block_groups(fs_info);
 
 	del_fs_roots(fs_info);
 
@@ -3057,14 +3093,17 @@ int close_ctree(struct btrfs_root *root)
 	btrfs_stop_workers(&fs_info->caching_workers);
 	btrfs_stop_workers(&fs_info->readahead_workers);
 
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+	if (btrfs_test_opt(root, CHECK_INTEGRITY))
+		btrfsic_unmount(root, fs_info->fs_devices);
+#endif
+
 	btrfs_close_devices(fs_info->fs_devices);
 	btrfs_mapping_tree_free(&fs_info->mapping_tree);
 
 	bdi_destroy(&fs_info->bdi);
 	cleanup_srcu_struct(&fs_info->subvol_srcu);
 
-	free_fs_info(fs_info);
-
 	return 0;
 }
 
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index c99d0a8f13f..e4bc4741319 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -46,9 +46,9 @@ struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 						   u64 bytenr, u32 blocksize);
 int clean_tree_block(struct btrfs_trans_handle *trans,
 		     struct btrfs_root *root, struct extent_buffer *buf);
-struct btrfs_root *open_ctree(struct super_block *sb,
-			      struct btrfs_fs_devices *fs_devices,
-			      char *options);
+int open_ctree(struct super_block *sb,
+	       struct btrfs_fs_devices *fs_devices,
+	       char *options);
 int close_ctree(struct btrfs_root *root);
 int write_ctree_super(struct btrfs_trans_handle *trans,
 		      struct btrfs_root *root, int max_mirrors);
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 1b8dc33778f..5f77166fd01 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -67,7 +67,7 @@ static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
 				       u64 root_objectid, u32 generation,
 				       int check_generation)
 {
-	struct btrfs_fs_info *fs_info = btrfs_sb(sb)->fs_info;
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 	struct btrfs_root *root;
 	struct inode *inode;
 	struct btrfs_key key;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index f5fbe576d2b..283af7a676a 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -34,23 +34,24 @@
 #include "locking.h"
 #include "free-space-cache.h"
 
-/* control flags for do_chunk_alloc's force field
+/*
+ * control flags for do_chunk_alloc's force field
  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  * if we really need one.
  *
- * CHUNK_ALLOC_FORCE means it must try to allocate one
- *
  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  * if we have very few chunks already allocated.  This is
  * used as part of the clustering code to help make sure
  * we have a good pool of storage to cluster in, without
  * filling the FS with empty chunks
  *
+ * CHUNK_ALLOC_FORCE means it must try to allocate one
+ *
  */
 enum {
 	CHUNK_ALLOC_NO_FORCE = 0,
-	CHUNK_ALLOC_FORCE = 1,
-	CHUNK_ALLOC_LIMITED = 2,
+	CHUNK_ALLOC_LIMITED = 1,
+	CHUNK_ALLOC_FORCE = 2,
 };
 
 /*
@@ -618,8 +619,7 @@ static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 	struct list_head *head = &info->space_info;
 	struct btrfs_space_info *found;
 
-	flags &= BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_SYSTEM |
-		 BTRFS_BLOCK_GROUP_METADATA;
+	flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(found, head, list) {
@@ -1872,20 +1872,24 @@ static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 			 struct btrfs_root *root,
 			 u64 bytenr, u64 num_bytes, u64 parent,
-			 u64 root_objectid, u64 owner, u64 offset)
+			 u64 root_objectid, u64 owner, u64 offset, int for_cow)
 {
 	int ret;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+
 	BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
 	       root_objectid == BTRFS_TREE_LOG_OBJECTID);
 
 	if (owner < BTRFS_FIRST_FREE_OBJECTID) {
-		ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
+		ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
+					num_bytes,
 					parent, root_objectid, (int)owner,
-					BTRFS_ADD_DELAYED_REF, NULL);
+					BTRFS_ADD_DELAYED_REF, NULL, for_cow);
 	} else {
-		ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
+		ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
+					num_bytes,
 					parent, root_objectid, owner, offset,
-					BTRFS_ADD_DELAYED_REF, NULL);
+					BTRFS_ADD_DELAYED_REF, NULL, for_cow);
 	}
 	return ret;
 }
@@ -2233,6 +2237,28 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
 		}
 
 		/*
+		 * locked_ref is the head node, so we have to go one
+		 * node back for any delayed ref updates
+		 */
+		ref = select_delayed_ref(locked_ref);
+
+		if (ref && ref->seq &&
+		    btrfs_check_delayed_seq(delayed_refs, ref->seq)) {
+			/*
+			 * there are still refs with lower seq numbers in the
+			 * process of being added. Don't run this ref yet.
+			 */
+			list_del_init(&locked_ref->cluster);
+			mutex_unlock(&locked_ref->mutex);
+			locked_ref = NULL;
+			delayed_refs->num_heads_ready++;
+			spin_unlock(&delayed_refs->lock);
+			cond_resched();
+			spin_lock(&delayed_refs->lock);
+			continue;
+		}
+
+		/*
 		 * record the must insert reserved flag before we
 		 * drop the spin lock.
 		 */
@@ -2242,11 +2268,6 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
 		extent_op = locked_ref->extent_op;
 		locked_ref->extent_op = NULL;
 
-		/*
-		 * locked_ref is the head node, so we have to go one
-		 * node back for any delayed ref updates
-		 */
-		ref = select_delayed_ref(locked_ref);
 		if (!ref) {
 			/* All delayed refs have been processed, Go ahead
 			 * and send the head node to run_one_delayed_ref,
@@ -2267,9 +2288,7 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
 				BUG_ON(ret);
 				kfree(extent_op);
 
-				cond_resched();
-				spin_lock(&delayed_refs->lock);
-				continue;
+				goto next;
 			}
 
 			list_del_init(&locked_ref->cluster);
@@ -2279,7 +2298,12 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
 		ref->in_tree = 0;
 		rb_erase(&ref->rb_node, &delayed_refs->root);
 		delayed_refs->num_entries--;
-
+		/*
+		 * we modified num_entries, but as we're currently running
+		 * delayed refs, skip
+		 *     wake_up(&delayed_refs->seq_wait);
+		 * here.
+		 */
 		spin_unlock(&delayed_refs->lock);
 
 		ret = run_one_delayed_ref(trans, root, ref, extent_op,
@@ -2289,13 +2313,34 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
 		btrfs_put_delayed_ref(ref);
 		kfree(extent_op);
 		count++;
-
+next:
+		do_chunk_alloc(trans, root->fs_info->extent_root,
+			       2 * 1024 * 1024,
+			       btrfs_get_alloc_profile(root, 0),
+			       CHUNK_ALLOC_NO_FORCE);
 		cond_resched();
 		spin_lock(&delayed_refs->lock);
 	}
 	return count;
 }
 
+
+static void wait_for_more_refs(struct btrfs_delayed_ref_root *delayed_refs,
+			unsigned long num_refs)
+{
+	struct list_head *first_seq = delayed_refs->seq_head.next;
+
+	spin_unlock(&delayed_refs->lock);
+	pr_debug("waiting for more refs (num %ld, first %p)\n",
+		 num_refs, first_seq);
+	wait_event(delayed_refs->seq_wait,
+		   num_refs != delayed_refs->num_entries ||
+		   delayed_refs->seq_head.next != first_seq);
+	pr_debug("done waiting for more refs (num %ld, first %p)\n",
+		 delayed_refs->num_entries, delayed_refs->seq_head.next);
+	spin_lock(&delayed_refs->lock);
+}
+
 /*
  * this starts processing the delayed reference count updates and
  * extent insertions we have queued up so far.  count can be
@@ -2311,15 +2356,23 @@ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
 	struct btrfs_delayed_ref_node *ref;
 	struct list_head cluster;
 	int ret;
+	u64 delayed_start;
 	int run_all = count == (unsigned long)-1;
 	int run_most = 0;
+	unsigned long num_refs = 0;
+	int consider_waiting;
 
 	if (root == root->fs_info->extent_root)
 		root = root->fs_info->tree_root;
 
+	do_chunk_alloc(trans, root->fs_info->extent_root,
+		       2 * 1024 * 1024, btrfs_get_alloc_profile(root, 0),
+		       CHUNK_ALLOC_NO_FORCE);
+
 	delayed_refs = &trans->transaction->delayed_refs;
 	INIT_LIST_HEAD(&cluster);
 again:
+	consider_waiting = 0;
 	spin_lock(&delayed_refs->lock);
 	if (count == 0) {
 		count = delayed_refs->num_entries * 2;
@@ -2336,11 +2389,35 @@ again:
 		 * of refs to process starting at the first one we are able to
 		 * lock
 		 */
+		delayed_start = delayed_refs->run_delayed_start;
 		ret = btrfs_find_ref_cluster(trans, &cluster,
 					     delayed_refs->run_delayed_start);
 		if (ret)
 			break;
 
+		if (delayed_start >= delayed_refs->run_delayed_start) {
+			if (consider_waiting == 0) {
+				/*
+				 * btrfs_find_ref_cluster looped. let's do one
+				 * more cycle. if we don't run any delayed ref
+				 * during that cycle (because we can't because
+				 * all of them are blocked) and if the number of
+				 * refs doesn't change, we avoid busy waiting.
+				 */
+				consider_waiting = 1;
+				num_refs = delayed_refs->num_entries;
+			} else {
+				wait_for_more_refs(delayed_refs, num_refs);
+				/*
+				 * after waiting, things have changed. we
+				 * dropped the lock and someone else might have
+				 * run some refs, built new clusters and so on.
+				 * therefore, we restart staleness detection.
+				 */
+				consider_waiting = 0;
+			}
+		}
+
 		ret = run_clustered_refs(trans, root, &cluster);
 		BUG_ON(ret < 0);
 
@@ -2348,6 +2425,11 @@ again:
 
 		if (count == 0)
 			break;
+
+		if (ret || delayed_refs->run_delayed_start == 0) {
+			/* refs were run, let's reset staleness detection */
+			consider_waiting = 0;
+		}
 	}
 
 	if (run_all) {
@@ -2405,7 +2487,8 @@ int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
 	extent_op->update_key = 0;
 	extent_op->is_data = is_data ? 1 : 0;
 
-	ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
+	ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
+					  num_bytes, extent_op);
 	if (ret)
 		kfree(extent_op);
 	return ret;
@@ -2590,7 +2673,7 @@ out:
 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
 			   struct btrfs_root *root,
 			   struct extent_buffer *buf,
-			   int full_backref, int inc)
+			   int full_backref, int inc, int for_cow)
 {
 	u64 bytenr;
 	u64 num_bytes;
@@ -2603,7 +2686,7 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
 	int level;
 	int ret = 0;
 	int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
-			    u64, u64, u64, u64, u64, u64);
+			    u64, u64, u64, u64, u64, u64, int);
 
 	ref_root = btrfs_header_owner(buf);
 	nritems = btrfs_header_nritems(buf);
@@ -2640,14 +2723,15 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
 			key.offset -= btrfs_file_extent_offset(buf, fi);
 			ret = process_func(trans, root, bytenr, num_bytes,
 					   parent, ref_root, key.objectid,
-					   key.offset);
+					   key.offset, for_cow);
 			if (ret)
 				goto fail;
 		} else {
 			bytenr = btrfs_node_blockptr(buf, i);
 			num_bytes = btrfs_level_size(root, level - 1);
 			ret = process_func(trans, root, bytenr, num_bytes,
-					   parent, ref_root, level - 1, 0);
+					   parent, ref_root, level - 1, 0,
+					   for_cow);
 			if (ret)
 				goto fail;
 		}
@@ -2659,15 +2743,15 @@ fail:
 }
 
 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
-		  struct extent_buffer *buf, int full_backref)
+		  struct extent_buffer *buf, int full_backref, int for_cow)
 {
-	return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
+	return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
 }
 
 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
-		  struct extent_buffer *buf, int full_backref)
+		  struct extent_buffer *buf, int full_backref, int for_cow)
 {
-	return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
+	return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
 }
 
 static int write_one_cache_group(struct btrfs_trans_handle *trans,
@@ -2993,9 +3077,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
 		INIT_LIST_HEAD(&found->block_groups[i]);
 	init_rwsem(&found->groups_sem);
 	spin_lock_init(&found->lock);
-	found->flags = flags & (BTRFS_BLOCK_GROUP_DATA |
-				BTRFS_BLOCK_GROUP_SYSTEM |
-				BTRFS_BLOCK_GROUP_METADATA);
+	found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
 	found->total_bytes = total_bytes;
 	found->disk_total = total_bytes * factor;
 	found->bytes_used = bytes_used;
@@ -3016,20 +3098,27 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
 
 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
 {
-	u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
-				   BTRFS_BLOCK_GROUP_RAID1 |
-				   BTRFS_BLOCK_GROUP_RAID10 |
-				   BTRFS_BLOCK_GROUP_DUP);
-	if (extra_flags) {
-		if (flags & BTRFS_BLOCK_GROUP_DATA)
-			fs_info->avail_data_alloc_bits |= extra_flags;
-		if (flags & BTRFS_BLOCK_GROUP_METADATA)
-			fs_info->avail_metadata_alloc_bits |= extra_flags;
-		if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
-			fs_info->avail_system_alloc_bits |= extra_flags;
-	}
+	u64 extra_flags = flags & BTRFS_BLOCK_GROUP_PROFILE_MASK;
+
+	/* chunk -> extended profile */
+	if (extra_flags == 0)
+		extra_flags = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+
+	if (flags & BTRFS_BLOCK_GROUP_DATA)
+		fs_info->avail_data_alloc_bits |= extra_flags;
+	if (flags & BTRFS_BLOCK_GROUP_METADATA)
+		fs_info->avail_metadata_alloc_bits |= extra_flags;
+	if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
+		fs_info->avail_system_alloc_bits |= extra_flags;
 }
 
+/*
+ * @flags: available profiles in extended format (see ctree.h)
+ *
+ * Returns reduced profile in chunk format.  If profile changing is in
+ * progress (either running or paused) picks the target profile (if it's
+ * already available), otherwise falls back to plain reducing.
+ */
 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
 {
 	/*
@@ -3040,6 +3129,34 @@ u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
 	u64 num_devices = root->fs_info->fs_devices->rw_devices +
 		root->fs_info->fs_devices->missing_devices;
 
+	/* pick restriper's target profile if it's available */
+	spin_lock(&root->fs_info->balance_lock);
+	if (root->fs_info->balance_ctl) {
+		struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
+		u64 tgt = 0;
+
+		if ((flags & BTRFS_BLOCK_GROUP_DATA) &&
+		    (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
+		    (flags & bctl->data.target)) {
+			tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
+		} else if ((flags & BTRFS_BLOCK_GROUP_SYSTEM) &&
+			   (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
+			   (flags & bctl->sys.target)) {
+			tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
+		} else if ((flags & BTRFS_BLOCK_GROUP_METADATA) &&
+			   (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
+			   (flags & bctl->meta.target)) {
+			tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
+		}
+
+		if (tgt) {
+			spin_unlock(&root->fs_info->balance_lock);
+			flags = tgt;
+			goto out;
+		}
+	}
+	spin_unlock(&root->fs_info->balance_lock);
+
 	if (num_devices == 1)
 		flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
 	if (num_devices < 4)
@@ -3059,22 +3176,25 @@ u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
 	if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
 	    ((flags & BTRFS_BLOCK_GROUP_RAID1) |
 	     (flags & BTRFS_BLOCK_GROUP_RAID10) |
-	     (flags & BTRFS_BLOCK_GROUP_DUP)))
+	     (flags & BTRFS_BLOCK_GROUP_DUP))) {
 		flags &= ~BTRFS_BLOCK_GROUP_RAID0;
+	}
+
+out:
+	/* extended -> chunk profile */
+	flags &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
 	return flags;
 }
 
 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
 {
 	if (flags & BTRFS_BLOCK_GROUP_DATA)
-		flags |= root->fs_info->avail_data_alloc_bits &
-			 root->fs_info->data_alloc_profile;
+		flags |= root->fs_info->avail_data_alloc_bits;
 	else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
-		flags |= root->fs_info->avail_system_alloc_bits &
-			 root->fs_info->system_alloc_profile;
+		flags |= root->fs_info->avail_system_alloc_bits;
 	else if (flags & BTRFS_BLOCK_GROUP_METADATA)
-		flags |= root->fs_info->avail_metadata_alloc_bits &
-			 root->fs_info->metadata_alloc_profile;
+		flags |= root->fs_info->avail_metadata_alloc_bits;
+
 	return btrfs_reduce_alloc_profile(root, flags);
 }
 
@@ -3191,6 +3311,8 @@ commit_trans:
 		return -ENOSPC;
 	}
 	data_sinfo->bytes_may_use += bytes;
+	trace_btrfs_space_reservation(root->fs_info, "space_info",
+				      (u64)data_sinfo, bytes, 1);
 	spin_unlock(&data_sinfo->lock);
 
 	return 0;
@@ -3210,6 +3332,8 @@ void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
 	data_sinfo = BTRFS_I(inode)->space_info;
 	spin_lock(&data_sinfo->lock);
 	data_sinfo->bytes_may_use -= bytes;
+	trace_btrfs_space_reservation(root->fs_info, "space_info",
+				      (u64)data_sinfo, bytes, 0);
 	spin_unlock(&data_sinfo->lock);
 }
 
@@ -3257,27 +3381,15 @@ static int should_alloc_chunk(struct btrfs_root *root,
 		if (num_bytes - num_allocated < thresh)
 			return 1;
 	}
-
-	/*
-	 * we have two similar checks here, one based on percentage
-	 * and once based on a hard number of 256MB.  The idea
-	 * is that if we have a good amount of free
-	 * room, don't allocate a chunk.  A good mount is
-	 * less than 80% utilized of the chunks we have allocated,
-	 * or more than 256MB free
-	 */
-	if (num_allocated + alloc_bytes + 256 * 1024 * 1024 < num_bytes)
-		return 0;
-
-	if (num_allocated + alloc_bytes < div_factor(num_bytes, 8))
-		return 0;
-
 	thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
 
-	/* 256MB or 5% of the FS */
-	thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 5));
+	/* 256MB or 2% of the FS */
+	thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 2));
+	/* system chunks need a much small threshold */
+	if (sinfo->flags & BTRFS_BLOCK_GROUP_SYSTEM)
+		thresh = 32 * 1024 * 1024;
 
-	if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 3))
+	if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 8))
 		return 0;
 	return 1;
 }
@@ -3291,7 +3403,7 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 	int wait_for_alloc = 0;
 	int ret = 0;
 
-	flags = btrfs_reduce_alloc_profile(extent_root, flags);
+	BUG_ON(!profile_is_valid(flags, 0));
 
 	space_info = __find_space_info(extent_root->fs_info, flags);
 	if (!space_info) {
@@ -3303,7 +3415,7 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 
 again:
 	spin_lock(&space_info->lock);
-	if (space_info->force_alloc)
+	if (force < space_info->force_alloc)
 		force = space_info->force_alloc;
 	if (space_info->full) {
 		spin_unlock(&space_info->lock);
@@ -3582,6 +3694,10 @@ again:
 	if (used <= space_info->total_bytes) {
 		if (used + orig_bytes <= space_info->total_bytes) {
 			space_info->bytes_may_use += orig_bytes;
+			trace_btrfs_space_reservation(root->fs_info,
+						      "space_info",
+						      (u64)space_info,
+						      orig_bytes, 1);
 			ret = 0;
 		} else {
 			/*
@@ -3649,6 +3765,10 @@ again:
 
 		if (used + num_bytes < space_info->total_bytes + avail) {
 			space_info->bytes_may_use += orig_bytes;
+			trace_btrfs_space_reservation(root->fs_info,
+						      "space_info",
+						      (u64)space_info,
+						      orig_bytes, 1);
 			ret = 0;
 		} else {
 			wait_ordered = true;
@@ -3755,7 +3875,8 @@ static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
 	spin_unlock(&block_rsv->lock);
 }
 
-static void block_rsv_release_bytes(struct btrfs_block_rsv *block_rsv,
+static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
+				    struct btrfs_block_rsv *block_rsv,
 				    struct btrfs_block_rsv *dest, u64 num_bytes)
 {
 	struct btrfs_space_info *space_info = block_rsv->space_info;
@@ -3791,6 +3912,9 @@ static void block_rsv_release_bytes(struct btrfs_block_rsv *block_rsv,
 		if (num_bytes) {
 			spin_lock(&space_info->lock);
 			space_info->bytes_may_use -= num_bytes;
+			trace_btrfs_space_reservation(fs_info, "space_info",
+						      (u64)space_info,
+						      num_bytes, 0);
 			space_info->reservation_progress++;
 			spin_unlock(&space_info->lock);
 		}
@@ -3947,7 +4071,8 @@ void btrfs_block_rsv_release(struct btrfs_root *root,
 	if (global_rsv->full || global_rsv == block_rsv ||
 	    block_rsv->space_info != global_rsv->space_info)
 		global_rsv = NULL;
-	block_rsv_release_bytes(block_rsv, global_rsv, num_bytes);
+	block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
+				num_bytes);
 }
 
 /*
@@ -4006,11 +4131,15 @@ static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
 		num_bytes = sinfo->total_bytes - num_bytes;
 		block_rsv->reserved += num_bytes;
 		sinfo->bytes_may_use += num_bytes;
+		trace_btrfs_space_reservation(fs_info, "space_info",
+					      (u64)sinfo, num_bytes, 1);
 	}
 
 	if (block_rsv->reserved >= block_rsv->size) {
 		num_bytes = block_rsv->reserved - block_rsv->size;
 		sinfo->bytes_may_use -= num_bytes;
+		trace_btrfs_space_reservation(fs_info, "space_info",
+					      (u64)sinfo, num_bytes, 0);
 		sinfo->reservation_progress++;
 		block_rsv->reserved = block_rsv->size;
 		block_rsv->full = 1;
@@ -4045,7 +4174,8 @@ static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
 
 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
 {
-	block_rsv_release_bytes(&fs_info->global_block_rsv, NULL, (u64)-1);
+	block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
+				(u64)-1);
 	WARN_ON(fs_info->delalloc_block_rsv.size > 0);
 	WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
 	WARN_ON(fs_info->trans_block_rsv.size > 0);
@@ -4062,6 +4192,8 @@ void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
 	if (!trans->bytes_reserved)
 		return;
 
+	trace_btrfs_space_reservation(root->fs_info, "transaction", (u64)trans,
+				      trans->bytes_reserved, 0);
 	btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
 	trans->bytes_reserved = 0;
 }
@@ -4079,6 +4211,8 @@ int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
 	 * when we are truly done with the orphan item.
 	 */
 	u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
+	trace_btrfs_space_reservation(root->fs_info, "orphan",
+				      btrfs_ino(inode), num_bytes, 1);
 	return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
 }
 
@@ -4086,6 +4220,8 @@ void btrfs_orphan_release_metadata(struct inode *inode)
 {
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 	u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
+	trace_btrfs_space_reservation(root->fs_info, "orphan",
+				      btrfs_ino(inode), num_bytes, 0);
 	btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
 }
 
@@ -4213,12 +4349,11 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
 	/* Need to be holding the i_mutex here if we aren't free space cache */
 	if (btrfs_is_free_space_inode(root, inode))
 		flush = 0;
-	else
-		WARN_ON(!mutex_is_locked(&inode->i_mutex));
 
 	if (flush && btrfs_transaction_in_commit(root->fs_info))
 		schedule_timeout(1);
 
+	mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
 	num_bytes = ALIGN(num_bytes, root->sectorsize);
 
 	spin_lock(&BTRFS_I(inode)->lock);
@@ -4266,8 +4401,14 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
 		if (dropped)
 			to_free += btrfs_calc_trans_metadata_size(root, dropped);
 
-		if (to_free)
+		if (to_free) {
 			btrfs_block_rsv_release(root, block_rsv, to_free);
+			trace_btrfs_space_reservation(root->fs_info,
+						      "delalloc",
+						      btrfs_ino(inode),
+						      to_free, 0);
+		}
+		mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
 		return ret;
 	}
 
@@ -4278,7 +4419,11 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
 	}
 	BTRFS_I(inode)->reserved_extents += nr_extents;
 	spin_unlock(&BTRFS_I(inode)->lock);
+	mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
 
+	if (to_reserve)
+		trace_btrfs_space_reservation(root->fs_info,"delalloc",
+					      btrfs_ino(inode), to_reserve, 1);
 	block_rsv_add_bytes(block_rsv, to_reserve, 1);
 
 	return 0;
@@ -4308,6 +4453,8 @@ void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
 	if (dropped > 0)
 		to_free += btrfs_calc_trans_metadata_size(root, dropped);
 
+	trace_btrfs_space_reservation(root->fs_info, "delalloc",
+				      btrfs_ino(inode), to_free, 0);
 	btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
 				to_free);
 }
@@ -4562,7 +4709,10 @@ static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 			cache->reserved += num_bytes;
 			space_info->bytes_reserved += num_bytes;
 			if (reserve == RESERVE_ALLOC) {
-				BUG_ON(space_info->bytes_may_use < num_bytes);
+				trace_btrfs_space_reservation(cache->fs_info,
+							      "space_info",
+							      (u64)space_info,
+							      num_bytes, 0);
 				space_info->bytes_may_use -= num_bytes;
 			}
 		}
@@ -4928,6 +5078,8 @@ static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
 	rb_erase(&head->node.rb_node, &delayed_refs->root);
 
 	delayed_refs->num_entries--;
+	if (waitqueue_active(&delayed_refs->seq_wait))
+		wake_up(&delayed_refs->seq_wait);
 
 	/*
 	 * we don't take a ref on the node because we're removing it from the
@@ -4955,16 +5107,17 @@ out:
 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
 			   struct btrfs_root *root,
 			   struct extent_buffer *buf,
-			   u64 parent, int last_ref)
+			   u64 parent, int last_ref, int for_cow)
 {
 	struct btrfs_block_group_cache *cache = NULL;
 	int ret;
 
 	if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
-		ret = btrfs_add_delayed_tree_ref(trans, buf->start, buf->len,
-						parent, root->root_key.objectid,
-						btrfs_header_level(buf),
-						BTRFS_DROP_DELAYED_REF, NULL);
+		ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
+					buf->start, buf->len,
+					parent, root->root_key.objectid,
+					btrfs_header_level(buf),
+					BTRFS_DROP_DELAYED_REF, NULL, for_cow);
 		BUG_ON(ret);
 	}
 
@@ -4999,12 +5152,12 @@ out:
 	btrfs_put_block_group(cache);
 }
 
-int btrfs_free_extent(struct btrfs_trans_handle *trans,
-		      struct btrfs_root *root,
-		      u64 bytenr, u64 num_bytes, u64 parent,
-		      u64 root_objectid, u64 owner, u64 offset)
+int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+		      u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
+		      u64 owner, u64 offset, int for_cow)
 {
 	int ret;
+	struct btrfs_fs_info *fs_info = root->fs_info;
 
 	/*
 	 * tree log blocks never actually go into the extent allocation
@@ -5016,14 +5169,17 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans,
 		btrfs_pin_extent(root, bytenr, num_bytes, 1);
 		ret = 0;
 	} else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
-		ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
+		ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
+					num_bytes,
 					parent, root_objectid, (int)owner,
-					BTRFS_DROP_DELAYED_REF, NULL);
+					BTRFS_DROP_DELAYED_REF, NULL, for_cow);
 		BUG_ON(ret);
 	} else {
-		ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
-					parent, root_objectid, owner,
-					offset, BTRFS_DROP_DELAYED_REF, NULL);
+		ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
+						num_bytes,
+						parent, root_objectid, owner,
+						offset, BTRFS_DROP_DELAYED_REF,
+						NULL, for_cow);
 		BUG_ON(ret);
 	}
 	return ret;
@@ -5146,6 +5302,8 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans,
 	ins->objectid = 0;
 	ins->offset = 0;
 
+	trace_find_free_extent(orig_root, num_bytes, empty_size, data);
+
 	space_info = __find_space_info(root->fs_info, data);
 	if (!space_info) {
 		printk(KERN_ERR "No space info for %llu\n", data);
@@ -5295,15 +5453,6 @@ alloc:
 		if (unlikely(block_group->ro))
 			goto loop;
 
-		spin_lock(&block_group->free_space_ctl->tree_lock);
-		if (cached &&
-		    block_group->free_space_ctl->free_space <
-		    num_bytes + empty_cluster + empty_size) {
-			spin_unlock(&block_group->free_space_ctl->tree_lock);
-			goto loop;
-		}
-		spin_unlock(&block_group->free_space_ctl->tree_lock);
-
 		/*
 		 * Ok we want to try and use the cluster allocator, so
 		 * lets look there
@@ -5331,6 +5480,8 @@ alloc:
 			if (offset) {
 				/* we have a block, we're done */
 				spin_unlock(&last_ptr->refill_lock);
+				trace_btrfs_reserve_extent_cluster(root,
+					block_group, search_start, num_bytes);
 				goto checks;
 			}
 
@@ -5349,8 +5500,15 @@ refill_cluster:
 			 * plenty of times and not have found
 			 * anything, so we are likely way too
 			 * fragmented for the clustering stuff to find
-			 * anything.  */
-			if (loop >= LOOP_NO_EMPTY_SIZE) {
+			 * anything.
+			 *
+			 * However, if the cluster is taken from the
+			 * current block group, release the cluster
+			 * first, so that we stand a better chance of
+			 * succeeding in the unclustered
+			 * allocation.  */
+			if (loop >= LOOP_NO_EMPTY_SIZE &&
+			    last_ptr->block_group != block_group) {
 				spin_unlock(&last_ptr->refill_lock);
 				goto unclustered_alloc;
 			}
@@ -5361,6 +5519,11 @@ refill_cluster:
 			 */
 			btrfs_return_cluster_to_free_space(NULL, last_ptr);
 
+			if (loop >= LOOP_NO_EMPTY_SIZE) {
+				spin_unlock(&last_ptr->refill_lock);
+				goto unclustered_alloc;
+			}
+
 			/* allocate a cluster in this block group */
 			ret = btrfs_find_space_cluster(trans, root,
 					       block_group, last_ptr,
@@ -5377,6 +5540,9 @@ refill_cluster:
 				if (offset) {
 					/* we found one, proceed */
 					spin_unlock(&last_ptr->refill_lock);
+					trace_btrfs_reserve_extent_cluster(root,
+						block_group, search_start,
+						num_bytes);
 					goto checks;
 				}
 			} else if (!cached && loop > LOOP_CACHING_NOWAIT
@@ -5401,6 +5567,15 @@ refill_cluster:
 		}
 
 unclustered_alloc:
+		spin_lock(&block_group->free_space_ctl->tree_lock);
+		if (cached &&
+		    block_group->free_space_ctl->free_space <
+		    num_bytes + empty_cluster + empty_size) {
+			spin_unlock(&block_group->free_space_ctl->tree_lock);
+			goto loop;
+		}
+		spin_unlock(&block_group->free_space_ctl->tree_lock);
+
 		offset = btrfs_find_space_for_alloc(block_group, search_start,
 						    num_bytes, empty_size);
 		/*
@@ -5438,9 +5613,6 @@ checks:
 			goto loop;
 		}
 
-		ins->objectid = search_start;
-		ins->offset = num_bytes;
-
 		if (offset < search_start)
 			btrfs_add_free_space(used_block_group, offset,
 					     search_start - offset);
@@ -5457,6 +5629,8 @@ checks:
 		ins->objectid = search_start;
 		ins->offset = num_bytes;
 
+		trace_btrfs_reserve_extent(orig_root, block_group,
+					   search_start, num_bytes);
 		if (offset < search_start)
 			btrfs_add_free_space(used_block_group, offset,
 					     search_start - offset);
@@ -5621,6 +5795,7 @@ int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
 			 u64 search_end, struct btrfs_key *ins,
 			 u64 data)
 {
+	bool final_tried = false;
 	int ret;
 	u64 search_start = 0;
 
@@ -5640,22 +5815,25 @@ again:
 			       search_start, search_end, hint_byte,
 			       ins, data);
 
-	if (ret == -ENOSPC && num_bytes > min_alloc_size) {
-		num_bytes = num_bytes >> 1;
-		num_bytes = num_bytes & ~(root->sectorsize - 1);
-		num_bytes = max(num_bytes, min_alloc_size);
-		do_chunk_alloc(trans, root->fs_info->extent_root,
-			       num_bytes, data, CHUNK_ALLOC_FORCE);
-		goto again;
-	}
-	if (ret == -ENOSPC && btrfs_test_opt(root, ENOSPC_DEBUG)) {
-		struct btrfs_space_info *sinfo;
-
-		sinfo = __find_space_info(root->fs_info, data);
-		printk(KERN_ERR "btrfs allocation failed flags %llu, "
-		       "wanted %llu\n", (unsigned long long)data,
-		       (unsigned long long)num_bytes);
-		dump_space_info(sinfo, num_bytes, 1);
+	if (ret == -ENOSPC) {
+		if (!final_tried) {
+			num_bytes = num_bytes >> 1;
+			num_bytes = num_bytes & ~(root->sectorsize - 1);
+			num_bytes = max(num_bytes, min_alloc_size);
+			do_chunk_alloc(trans, root->fs_info->extent_root,
+				       num_bytes, data, CHUNK_ALLOC_FORCE);
+			if (num_bytes == min_alloc_size)
+				final_tried = true;
+			goto again;
+		} else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
+			struct btrfs_space_info *sinfo;
+
+			sinfo = __find_space_info(root->fs_info, data);
+			printk(KERN_ERR "btrfs allocation failed flags %llu, "
+			       "wanted %llu\n", (unsigned long long)data,
+			       (unsigned long long)num_bytes);
+			dump_space_info(sinfo, num_bytes, 1);
+		}
 	}
 
 	trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
@@ -5842,9 +6020,10 @@ int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
 
 	BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
 
-	ret = btrfs_add_delayed_data_ref(trans, ins->objectid, ins->offset,
-					 0, root_objectid, owner, offset,
-					 BTRFS_ADD_DELAYED_EXTENT, NULL);
+	ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
+					 ins->offset, 0,
+					 root_objectid, owner, offset,
+					 BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
 	return ret;
 }
 
@@ -5997,10 +6176,11 @@ use_block_rsv(struct btrfs_trans_handle *trans,
 	return ERR_PTR(-ENOSPC);
 }
 
-static void unuse_block_rsv(struct btrfs_block_rsv *block_rsv, u32 blocksize)
+static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
+			    struct btrfs_block_rsv *block_rsv, u32 blocksize)
 {
 	block_rsv_add_bytes(block_rsv, blocksize, 0);
-	block_rsv_release_bytes(block_rsv, NULL, 0);
+	block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
 }
 
 /*
@@ -6014,7 +6194,7 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 					struct btrfs_root *root, u32 blocksize,
 					u64 parent, u64 root_objectid,
 					struct btrfs_disk_key *key, int level,
-					u64 hint, u64 empty_size)
+					u64 hint, u64 empty_size, int for_cow)
 {
 	struct btrfs_key ins;
 	struct btrfs_block_rsv *block_rsv;
@@ -6030,7 +6210,7 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 	ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
 				   empty_size, hint, (u64)-1, &ins, 0);
 	if (ret) {
-		unuse_block_rsv(block_rsv, blocksize);
+		unuse_block_rsv(root->fs_info, block_rsv, blocksize);
 		return ERR_PTR(ret);
 	}
 
@@ -6058,10 +6238,11 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 		extent_op->update_flags = 1;
 		extent_op->is_data = 0;
 
-		ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
+		ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
+					ins.objectid,
 					ins.offset, parent, root_objectid,
 					level, BTRFS_ADD_DELAYED_EXTENT,
-					extent_op);
+					extent_op, for_cow);
 		BUG_ON(ret);
 	}
 	return buf;
@@ -6078,6 +6259,7 @@ struct walk_control {
 	int keep_locks;
 	int reada_slot;
 	int reada_count;
+	int for_reloc;
 };
 
 #define DROP_REFERENCE	1
@@ -6216,9 +6398,9 @@ static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
 	/* wc->stage == UPDATE_BACKREF */
 	if (!(wc->flags[level] & flag)) {
 		BUG_ON(!path->locks[level]);
-		ret = btrfs_inc_ref(trans, root, eb, 1);
+		ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
 		BUG_ON(ret);
-		ret = btrfs_dec_ref(trans, root, eb, 0);
+		ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
 		BUG_ON(ret);
 		ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
 						  eb->len, flag, 0);
@@ -6362,7 +6544,7 @@ skip:
 		}
 
 		ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
-					root->root_key.objectid, level - 1, 0);
+				root->root_key.objectid, level - 1, 0, 0);
 		BUG_ON(ret);
 	}
 	btrfs_tree_unlock(next);
@@ -6436,9 +6618,11 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
 	if (wc->refs[level] == 1) {
 		if (level == 0) {
 			if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
-				ret = btrfs_dec_ref(trans, root, eb, 1);
+				ret = btrfs_dec_ref(trans, root, eb, 1,
+						    wc->for_reloc);
 			else
-				ret = btrfs_dec_ref(trans, root, eb, 0);
+				ret = btrfs_dec_ref(trans, root, eb, 0,
+						    wc->for_reloc);
 			BUG_ON(ret);
 		}
 		/* make block locked assertion in clean_tree_block happy */
@@ -6465,7 +6649,7 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
 			       btrfs_header_owner(path->nodes[level + 1]));
 	}
 
-	btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
+	btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1, 0);
 out:
 	wc->refs[level] = 0;
 	wc->flags[level] = 0;
@@ -6549,7 +6733,8 @@ static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
  * blocks are properly updated.
  */
 void btrfs_drop_snapshot(struct btrfs_root *root,
-			 struct btrfs_block_rsv *block_rsv, int update_ref)
+			 struct btrfs_block_rsv *block_rsv, int update_ref,
+			 int for_reloc)
 {
 	struct btrfs_path *path;
 	struct btrfs_trans_handle *trans;
@@ -6637,6 +6822,7 @@ void btrfs_drop_snapshot(struct btrfs_root *root,
 	wc->stage = DROP_REFERENCE;
 	wc->update_ref = update_ref;
 	wc->keep_locks = 0;
+	wc->for_reloc = for_reloc;
 	wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
 
 	while (1) {
@@ -6721,6 +6907,7 @@ out:
  * drop subtree rooted at tree block 'node'.
  *
  * NOTE: this function will unlock and release tree block 'node'
+ * only used by relocation code
  */
 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
 			struct btrfs_root *root,
@@ -6765,6 +6952,7 @@ int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
 	wc->stage = DROP_REFERENCE;
 	wc->update_ref = 0;
 	wc->keep_locks = 1;
+	wc->for_reloc = 1;
 	wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
 
 	while (1) {
@@ -6792,6 +6980,29 @@ static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
 	u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
 		BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
 
+	if (root->fs_info->balance_ctl) {
+		struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
+		u64 tgt = 0;
+
+		/* pick restriper's target profile and return */
+		if (flags & BTRFS_BLOCK_GROUP_DATA &&
+		    bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
+			tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
+		} else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
+			   bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
+			tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
+		} else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
+			   bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
+			tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
+		}
+
+		if (tgt) {
+			/* extended -> chunk profile */
+			tgt &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+			return tgt;
+		}
+	}
+
 	/*
 	 * we add in the count of missing devices because we want
 	 * to make sure that any RAID levels on a degraded FS
@@ -7085,7 +7296,7 @@ int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
 		 * space to fit our block group in.
 		 */
 		if (device->total_bytes > device->bytes_used + min_free) {
-			ret = find_free_dev_extent(NULL, device, min_free,
+			ret = find_free_dev_extent(device, min_free,
 						   &dev_offset, NULL);
 			if (!ret)
 				dev_nr++;
@@ -7447,6 +7658,7 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
 	ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
 				&cache->space_info);
 	BUG_ON(ret);
+	update_global_block_rsv(root->fs_info);
 
 	spin_lock(&cache->space_info->lock);
 	cache->space_info->bytes_readonly += cache->bytes_super;
@@ -7466,6 +7678,22 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
 	return 0;
 }
 
+static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
+{
+	u64 extra_flags = flags & BTRFS_BLOCK_GROUP_PROFILE_MASK;
+
+	/* chunk -> extended profile */
+	if (extra_flags == 0)
+		extra_flags = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+
+	if (flags & BTRFS_BLOCK_GROUP_DATA)
+		fs_info->avail_data_alloc_bits &= ~extra_flags;
+	if (flags & BTRFS_BLOCK_GROUP_METADATA)
+		fs_info->avail_metadata_alloc_bits &= ~extra_flags;
+	if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
+		fs_info->avail_system_alloc_bits &= ~extra_flags;
+}
+
 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *root, u64 group_start)
 {
@@ -7476,6 +7704,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 	struct btrfs_key key;
 	struct inode *inode;
 	int ret;
+	int index;
 	int factor;
 
 	root = root->fs_info->extent_root;
@@ -7491,6 +7720,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 	free_excluded_extents(root, block_group);
 
 	memcpy(&key, &block_group->key, sizeof(key));
+	index = get_block_group_index(block_group);
 	if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
 				  BTRFS_BLOCK_GROUP_RAID1 |
 				  BTRFS_BLOCK_GROUP_RAID10))
@@ -7565,6 +7795,8 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 	 * are still on the list after taking the semaphore
 	 */
 	list_del_init(&block_group->list);
+	if (list_empty(&block_group->space_info->block_groups[index]))
+		clear_avail_alloc_bits(root->fs_info, block_group->flags);
 	up_write(&block_group->space_info->groups_sem);
 
 	if (block_group->cached == BTRFS_CACHE_STARTED)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 49f3c9dc09f..fcf77e1ded4 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -18,6 +18,7 @@
 #include "ctree.h"
 #include "btrfs_inode.h"
 #include "volumes.h"
+#include "check-integrity.h"
 
 static struct kmem_cache *extent_state_cache;
 static struct kmem_cache *extent_buffer_cache;
@@ -1895,7 +1896,7 @@ int repair_io_failure(struct btrfs_mapping_tree *map_tree, u64 start,
 	}
 	bio->bi_bdev = dev->bdev;
 	bio_add_page(bio, page, length, start-page_offset(page));
-	submit_bio(WRITE_SYNC, bio);
+	btrfsic_submit_bio(WRITE_SYNC, bio);
 	wait_for_completion(&compl);
 
 	if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
@@ -2393,7 +2394,7 @@ static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
 		ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
 					   mirror_num, bio_flags, start);
 	else
-		submit_bio(rw, bio);
+		btrfsic_submit_bio(rw, bio);
 
 	if (bio_flagged(bio, BIO_EOPNOTSUPP))
 		ret = -EOPNOTSUPP;
@@ -3579,6 +3580,7 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
 	atomic_set(&eb->blocking_writers, 0);
 	atomic_set(&eb->spinning_readers, 0);
 	atomic_set(&eb->spinning_writers, 0);
+	eb->lock_nested = 0;
 	init_waitqueue_head(&eb->write_lock_wq);
 	init_waitqueue_head(&eb->read_lock_wq);
 
@@ -3907,6 +3909,8 @@ int extent_range_uptodate(struct extent_io_tree *tree,
 	while (start <= end) {
 		index = start >> PAGE_CACHE_SHIFT;
 		page = find_get_page(tree->mapping, index);
+		if (!page)
+			return 1;
 		uptodate = PageUptodate(page);
 		page_cache_release(page);
 		if (!uptodate) {
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 7604c300132..bc6a042cb6f 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -129,6 +129,7 @@ struct extent_buffer {
 	struct list_head leak_list;
 	struct rcu_head rcu_head;
 	atomic_t refs;
+	pid_t lock_owner;
 
 	/* count of read lock holders on the extent buffer */
 	atomic_t write_locks;
@@ -137,6 +138,7 @@ struct extent_buffer {
 	atomic_t blocking_readers;
 	atomic_t spinning_readers;
 	atomic_t spinning_writers;
+	int lock_nested;
 
 	/* protects write locks */
 	rwlock_t lock;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 97fbe939c05..859ba2dd889 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -678,7 +678,7 @@ next_slot:
 						disk_bytenr, num_bytes, 0,
 						root->root_key.objectid,
 						new_key.objectid,
-						start - extent_offset);
+						start - extent_offset, 0);
 				BUG_ON(ret);
 				*hint_byte = disk_bytenr;
 			}
@@ -753,7 +753,7 @@ next_slot:
 						disk_bytenr, num_bytes, 0,
 						root->root_key.objectid,
 						key.objectid, key.offset -
-						extent_offset);
+						extent_offset, 0);
 				BUG_ON(ret);
 				inode_sub_bytes(inode,
 						extent_end - key.offset);
@@ -962,7 +962,7 @@ again:
 
 		ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
 					   root->root_key.objectid,
-					   ino, orig_offset);
+					   ino, orig_offset, 0);
 		BUG_ON(ret);
 
 		if (split == start) {
@@ -989,7 +989,7 @@ again:
 		del_nr++;
 		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 					0, root->root_key.objectid,
-					ino, orig_offset);
+					ino, orig_offset, 0);
 		BUG_ON(ret);
 	}
 	other_start = 0;
@@ -1006,7 +1006,7 @@ again:
 		del_nr++;
 		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 					0, root->root_key.objectid,
-					ino, orig_offset);
+					ino, orig_offset, 0);
 		BUG_ON(ret);
 	}
 	if (del_nr == 0) {
@@ -1081,7 +1081,7 @@ static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
 again:
 	for (i = 0; i < num_pages; i++) {
 		pages[i] = find_or_create_page(inode->i_mapping, index + i,
-					       mask);
+					       mask | __GFP_WRITE);
 		if (!pages[i]) {
 			faili = i - 1;
 			err = -ENOMEM;
@@ -1136,7 +1136,8 @@ again:
 				     GFP_NOFS);
 	}
 	for (i = 0; i < num_pages; i++) {
-		clear_page_dirty_for_io(pages[i]);
+		if (clear_page_dirty_for_io(pages[i]))
+			account_page_redirty(pages[i]);
 		set_page_extent_mapped(pages[i]);
 		WARN_ON(!PageLocked(pages[i]));
 	}
@@ -1273,7 +1274,6 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
 						   dirty_pages);
 		if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
 			btrfs_btree_balance_dirty(root, 1);
-		btrfs_throttle(root);
 
 		pos += copied;
 		num_written += copied;
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index ec23d43d0c3..c2f20594c9f 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -319,9 +319,11 @@ static void io_ctl_drop_pages(struct io_ctl *io_ctl)
 	io_ctl_unmap_page(io_ctl);
 
 	for (i = 0; i < io_ctl->num_pages; i++) {
-		ClearPageChecked(io_ctl->pages[i]);
-		unlock_page(io_ctl->pages[i]);
-		page_cache_release(io_ctl->pages[i]);
+		if (io_ctl->pages[i]) {
+			ClearPageChecked(io_ctl->pages[i]);
+			unlock_page(io_ctl->pages[i]);
+			page_cache_release(io_ctl->pages[i]);
+		}
 	}
 }
 
@@ -423,7 +425,7 @@ static void io_ctl_set_crc(struct io_ctl *io_ctl, int index)
 	}
 
 	if (index == 0)
-		offset = sizeof(u32) * io_ctl->num_pages;;
+		offset = sizeof(u32) * io_ctl->num_pages;
 
 	crc = btrfs_csum_data(io_ctl->root, io_ctl->orig + offset, crc,
 			      PAGE_CACHE_SIZE - offset);
@@ -635,7 +637,10 @@ int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 	if (!num_entries)
 		return 0;
 
-	io_ctl_init(&io_ctl, inode, root);
+	ret = io_ctl_init(&io_ctl, inode, root);
+	if (ret)
+		return ret;
+
 	ret = readahead_cache(inode);
 	if (ret)
 		goto out;
@@ -838,7 +843,7 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 	struct io_ctl io_ctl;
 	struct list_head bitmap_list;
 	struct btrfs_key key;
-	u64 start, end, len;
+	u64 start, extent_start, extent_end, len;
 	int entries = 0;
 	int bitmaps = 0;
 	int ret;
@@ -849,7 +854,9 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 	if (!i_size_read(inode))
 		return -1;
 
-	io_ctl_init(&io_ctl, inode, root);
+	ret = io_ctl_init(&io_ctl, inode, root);
+	if (ret)
+		return -1;
 
 	/* Get the cluster for this block_group if it exists */
 	if (block_group && !list_empty(&block_group->cluster_list))
@@ -857,25 +864,12 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 				     struct btrfs_free_cluster,
 				     block_group_list);
 
-	/*
-	 * We shouldn't have switched the pinned extents yet so this is the
-	 * right one
-	 */
-	unpin = root->fs_info->pinned_extents;
-
 	/* Lock all pages first so we can lock the extent safely. */
 	io_ctl_prepare_pages(&io_ctl, inode, 0);
 
 	lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
 			 0, &cached_state, GFP_NOFS);
 
-	/*
-	 * When searching for pinned extents, we need to start at our start
-	 * offset.
-	 */
-	if (block_group)
-		start = block_group->key.objectid;
-
 	node = rb_first(&ctl->free_space_offset);
 	if (!node && cluster) {
 		node = rb_first(&cluster->root);
@@ -918,9 +912,20 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 	 * We want to add any pinned extents to our free space cache
 	 * so we don't leak the space
 	 */
+
+	/*
+	 * We shouldn't have switched the pinned extents yet so this is the
+	 * right one
+	 */
+	unpin = root->fs_info->pinned_extents;
+
+	if (block_group)
+		start = block_group->key.objectid;
+
 	while (block_group && (start < block_group->key.objectid +
 			       block_group->key.offset)) {
-		ret = find_first_extent_bit(unpin, start, &start, &end,
+		ret = find_first_extent_bit(unpin, start,
+					    &extent_start, &extent_end,
 					    EXTENT_DIRTY);
 		if (ret) {
 			ret = 0;
@@ -928,20 +933,21 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 		}
 
 		/* This pinned extent is out of our range */
-		if (start >= block_group->key.objectid +
+		if (extent_start >= block_group->key.objectid +
 		    block_group->key.offset)
 			break;
 
-		len = block_group->key.objectid +
-			block_group->key.offset - start;
-		len = min(len, end + 1 - start);
+		extent_start = max(extent_start, start);
+		extent_end = min(block_group->key.objectid +
+				 block_group->key.offset, extent_end + 1);
+		len = extent_end - extent_start;
 
 		entries++;
-		ret = io_ctl_add_entry(&io_ctl, start, len, NULL);
+		ret = io_ctl_add_entry(&io_ctl, extent_start, len, NULL);
 		if (ret)
 			goto out_nospc;
 
-		start = end + 1;
+		start = extent_end;
 	}
 
 	/* Write out the bitmaps */
@@ -2236,7 +2242,7 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
 		if (entry->bitmap) {
 			ret = btrfs_alloc_from_bitmap(block_group,
 						      cluster, entry, bytes,
-						      min_start);
+						      cluster->window_start);
 			if (ret == 0) {
 				node = rb_next(&entry->offset_index);
 				if (!node)
@@ -2245,6 +2251,7 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
 						 offset_index);
 				continue;
 			}
+			cluster->window_start += bytes;
 		} else {
 			ret = entry->offset;
 
@@ -2283,23 +2290,23 @@ out:
 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
 				struct btrfs_free_space *entry,
 				struct btrfs_free_cluster *cluster,
-				u64 offset, u64 bytes, u64 min_bytes)
+				u64 offset, u64 bytes,
+				u64 cont1_bytes, u64 min_bytes)
 {
 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 	unsigned long next_zero;
 	unsigned long i;
-	unsigned long search_bits;
-	unsigned long total_bits;
+	unsigned long want_bits;
+	unsigned long min_bits;
 	unsigned long found_bits;
 	unsigned long start = 0;
 	unsigned long total_found = 0;
 	int ret;
-	bool found = false;
 
 	i = offset_to_bit(entry->offset, block_group->sectorsize,
 			  max_t(u64, offset, entry->offset));
-	search_bits = bytes_to_bits(bytes, block_group->sectorsize);
-	total_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
+	want_bits = bytes_to_bits(bytes, block_group->sectorsize);
+	min_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
 
 again:
 	found_bits = 0;
@@ -2308,7 +2315,7 @@ again:
 	     i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
 		next_zero = find_next_zero_bit(entry->bitmap,
 					       BITS_PER_BITMAP, i);
-		if (next_zero - i >= search_bits) {
+		if (next_zero - i >= min_bits) {
 			found_bits = next_zero - i;
 			break;
 		}
@@ -2318,10 +2325,9 @@ again:
 	if (!found_bits)
 		return -ENOSPC;
 
-	if (!found) {
+	if (!total_found) {
 		start = i;
 		cluster->max_size = 0;
-		found = true;
 	}
 
 	total_found += found_bits;
@@ -2329,13 +2335,8 @@ again:
 	if (cluster->max_size < found_bits * block_group->sectorsize)
 		cluster->max_size = found_bits * block_group->sectorsize;
 
-	if (total_found < total_bits) {
-		i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, next_zero);
-		if (i - start > total_bits * 2) {
-			total_found = 0;
-			cluster->max_size = 0;
-			found = false;
-		}
+	if (total_found < want_bits || cluster->max_size < cont1_bytes) {
+		i = next_zero + 1;
 		goto again;
 	}
 
@@ -2346,28 +2347,31 @@ again:
 				 &entry->offset_index, 1);
 	BUG_ON(ret);
 
+	trace_btrfs_setup_cluster(block_group, cluster,
+				  total_found * block_group->sectorsize, 1);
 	return 0;
 }
 
 /*
  * This searches the block group for just extents to fill the cluster with.
+ * Try to find a cluster with at least bytes total bytes, at least one
+ * extent of cont1_bytes, and other clusters of at least min_bytes.
  */
 static noinline int
 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
 			struct btrfs_free_cluster *cluster,
 			struct list_head *bitmaps, u64 offset, u64 bytes,
-			u64 min_bytes)
+			u64 cont1_bytes, u64 min_bytes)
 {
 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 	struct btrfs_free_space *first = NULL;
 	struct btrfs_free_space *entry = NULL;
-	struct btrfs_free_space *prev = NULL;
 	struct btrfs_free_space *last;
 	struct rb_node *node;
 	u64 window_start;
 	u64 window_free;
 	u64 max_extent;
-	u64 max_gap = 128 * 1024;
+	u64 total_size = 0;
 
 	entry = tree_search_offset(ctl, offset, 0, 1);
 	if (!entry)
@@ -2377,8 +2381,8 @@ setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
 	 * We don't want bitmaps, so just move along until we find a normal
 	 * extent entry.
 	 */
-	while (entry->bitmap) {
-		if (list_empty(&entry->list))
+	while (entry->bitmap || entry->bytes < min_bytes) {
+		if (entry->bitmap && list_empty(&entry->list))
 			list_add_tail(&entry->list, bitmaps);
 		node = rb_next(&entry->offset_index);
 		if (!node)
@@ -2391,12 +2395,9 @@ setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
 	max_extent = entry->bytes;
 	first = entry;
 	last = entry;
-	prev = entry;
 
-	while (window_free <= min_bytes) {
-		node = rb_next(&entry->offset_index);
-		if (!node)
-			return -ENOSPC;
+	for (node = rb_next(&entry->offset_index); node;
+	     node = rb_next(&entry->offset_index)) {
 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
 
 		if (entry->bitmap) {
@@ -2405,26 +2406,18 @@ setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
 			continue;
 		}
 
-		/*
-		 * we haven't filled the empty size and the window is
-		 * very large.  reset and try again
-		 */
-		if (entry->offset - (prev->offset + prev->bytes) > max_gap ||
-		    entry->offset - window_start > (min_bytes * 2)) {
-			first = entry;
-			window_start = entry->offset;
-			window_free = entry->bytes;
-			last = entry;
+		if (entry->bytes < min_bytes)
+			continue;
+
+		last = entry;
+		window_free += entry->bytes;
+		if (entry->bytes > max_extent)
 			max_extent = entry->bytes;
-		} else {
-			last = entry;
-			window_free += entry->bytes;
-			if (entry->bytes > max_extent)
-				max_extent = entry->bytes;
-		}
-		prev = entry;
 	}
 
+	if (window_free < bytes || max_extent < cont1_bytes)
+		return -ENOSPC;
+
 	cluster->window_start = first->offset;
 
 	node = &first->offset_index;
@@ -2438,17 +2431,18 @@ setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
 
 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
 		node = rb_next(&entry->offset_index);
-		if (entry->bitmap)
+		if (entry->bitmap || entry->bytes < min_bytes)
 			continue;
 
 		rb_erase(&entry->offset_index, &ctl->free_space_offset);
 		ret = tree_insert_offset(&cluster->root, entry->offset,
 					 &entry->offset_index, 0);
+		total_size += entry->bytes;
 		BUG_ON(ret);
 	} while (node && entry != last);
 
 	cluster->max_size = max_extent;
-
+	trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
 	return 0;
 }
 
@@ -2460,7 +2454,7 @@ static noinline int
 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
 		     struct btrfs_free_cluster *cluster,
 		     struct list_head *bitmaps, u64 offset, u64 bytes,
-		     u64 min_bytes)
+		     u64 cont1_bytes, u64 min_bytes)
 {
 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 	struct btrfs_free_space *entry;
@@ -2482,10 +2476,10 @@ setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
 	}
 
 	list_for_each_entry(entry, bitmaps, list) {
-		if (entry->bytes < min_bytes)
+		if (entry->bytes < bytes)
 			continue;
 		ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
-					   bytes, min_bytes);
+					   bytes, cont1_bytes, min_bytes);
 		if (!ret)
 			return 0;
 	}
@@ -2499,7 +2493,7 @@ setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
 
 /*
  * here we try to find a cluster of blocks in a block group.  The goal
- * is to find at least bytes free and up to empty_size + bytes free.
+ * is to find at least bytes+empty_size.
  * We might not find them all in one contiguous area.
  *
  * returns zero and sets up cluster if things worked out, otherwise
@@ -2515,23 +2509,24 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
 	struct btrfs_free_space *entry, *tmp;
 	LIST_HEAD(bitmaps);
 	u64 min_bytes;
+	u64 cont1_bytes;
 	int ret;
 
-	/* for metadata, allow allocates with more holes */
+	/*
+	 * Choose the minimum extent size we'll require for this
+	 * cluster.  For SSD_SPREAD, don't allow any fragmentation.
+	 * For metadata, allow allocates with smaller extents.  For
+	 * data, keep it dense.
+	 */
 	if (btrfs_test_opt(root, SSD_SPREAD)) {
-		min_bytes = bytes + empty_size;
+		cont1_bytes = min_bytes = bytes + empty_size;
 	} else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
-		/*
-		 * we want to do larger allocations when we are
-		 * flushing out the delayed refs, it helps prevent
-		 * making more work as we go along.
-		 */
-		if (trans->transaction->delayed_refs.flushing)
-			min_bytes = max(bytes, (bytes + empty_size) >> 1);
-		else
-			min_bytes = max(bytes, (bytes + empty_size) >> 4);
-	} else
-		min_bytes = max(bytes, (bytes + empty_size) >> 2);
+		cont1_bytes = bytes;
+		min_bytes = block_group->sectorsize;
+	} else {
+		cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
+		min_bytes = block_group->sectorsize;
+	}
 
 	spin_lock(&ctl->tree_lock);
 
@@ -2539,7 +2534,7 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
 	 * If we know we don't have enough space to make a cluster don't even
 	 * bother doing all the work to try and find one.
 	 */
-	if (ctl->free_space < min_bytes) {
+	if (ctl->free_space < bytes) {
 		spin_unlock(&ctl->tree_lock);
 		return -ENOSPC;
 	}
@@ -2552,11 +2547,17 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
 		goto out;
 	}
 
+	trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
+				 min_bytes);
+
+	INIT_LIST_HEAD(&bitmaps);
 	ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
-				      bytes, min_bytes);
+				      bytes + empty_size,
+				      cont1_bytes, min_bytes);
 	if (ret)
 		ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
-					   offset, bytes, min_bytes);
+					   offset, bytes + empty_size,
+					   cont1_bytes, min_bytes);
 
 	/* Clear our temporary list */
 	list_for_each_entry_safe(entry, tmp, &bitmaps, list)
@@ -2567,6 +2568,8 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
 		list_add_tail(&cluster->block_group_list,
 			      &block_group->cluster_list);
 		cluster->block_group = block_group;
+	} else {
+		trace_btrfs_failed_cluster_setup(block_group);
 	}
 out:
 	spin_unlock(&cluster->lock);
@@ -2588,17 +2591,57 @@ void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
 	cluster->block_group = NULL;
 }
 
-int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
-			   u64 *trimmed, u64 start, u64 end, u64 minlen)
+static int do_trimming(struct btrfs_block_group_cache *block_group,
+		       u64 *total_trimmed, u64 start, u64 bytes,
+		       u64 reserved_start, u64 reserved_bytes)
 {
-	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
-	struct btrfs_free_space *entry = NULL;
+	struct btrfs_space_info *space_info = block_group->space_info;
 	struct btrfs_fs_info *fs_info = block_group->fs_info;
-	u64 bytes = 0;
-	u64 actually_trimmed;
-	int ret = 0;
+	int ret;
+	int update = 0;
+	u64 trimmed = 0;
 
-	*trimmed = 0;
+	spin_lock(&space_info->lock);
+	spin_lock(&block_group->lock);
+	if (!block_group->ro) {
+		block_group->reserved += reserved_bytes;
+		space_info->bytes_reserved += reserved_bytes;
+		update = 1;
+	}
+	spin_unlock(&block_group->lock);
+	spin_unlock(&space_info->lock);
+
+	ret = btrfs_error_discard_extent(fs_info->extent_root,
+					 start, bytes, &trimmed);
+	if (!ret)
+		*total_trimmed += trimmed;
+
+	btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
+
+	if (update) {
+		spin_lock(&space_info->lock);
+		spin_lock(&block_group->lock);
+		if (block_group->ro)
+			space_info->bytes_readonly += reserved_bytes;
+		block_group->reserved -= reserved_bytes;
+		space_info->bytes_reserved -= reserved_bytes;
+		spin_unlock(&space_info->lock);
+		spin_unlock(&block_group->lock);
+	}
+
+	return ret;
+}
+
+static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
+			  u64 *total_trimmed, u64 start, u64 end, u64 minlen)
+{
+	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
+	struct btrfs_free_space *entry;
+	struct rb_node *node;
+	int ret = 0;
+	u64 extent_start;
+	u64 extent_bytes;
+	u64 bytes;
 
 	while (start < end) {
 		spin_lock(&ctl->tree_lock);
@@ -2609,81 +2652,118 @@ int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
 		}
 
 		entry = tree_search_offset(ctl, start, 0, 1);
-		if (!entry)
-			entry = tree_search_offset(ctl,
-						   offset_to_bitmap(ctl, start),
-						   1, 1);
-
-		if (!entry || entry->offset >= end) {
+		if (!entry) {
 			spin_unlock(&ctl->tree_lock);
 			break;
 		}
 
-		if (entry->bitmap) {
-			ret = search_bitmap(ctl, entry, &start, &bytes);
-			if (!ret) {
-				if (start >= end) {
-					spin_unlock(&ctl->tree_lock);
-					break;
-				}
-				bytes = min(bytes, end - start);
-				bitmap_clear_bits(ctl, entry, start, bytes);
-				if (entry->bytes == 0)
-					free_bitmap(ctl, entry);
-			} else {
-				start = entry->offset + BITS_PER_BITMAP *
-					block_group->sectorsize;
+		/* skip bitmaps */
+		while (entry->bitmap) {
+			node = rb_next(&entry->offset_index);
+			if (!node) {
 				spin_unlock(&ctl->tree_lock);
-				ret = 0;
-				continue;
+				goto out;
 			}
-		} else {
-			start = entry->offset;
-			bytes = min(entry->bytes, end - start);
-			unlink_free_space(ctl, entry);
-			kmem_cache_free(btrfs_free_space_cachep, entry);
+			entry = rb_entry(node, struct btrfs_free_space,
+					 offset_index);
 		}
 
+		if (entry->offset >= end) {
+			spin_unlock(&ctl->tree_lock);
+			break;
+		}
+
+		extent_start = entry->offset;
+		extent_bytes = entry->bytes;
+		start = max(start, extent_start);
+		bytes = min(extent_start + extent_bytes, end) - start;
+		if (bytes < minlen) {
+			spin_unlock(&ctl->tree_lock);
+			goto next;
+		}
+
+		unlink_free_space(ctl, entry);
+		kmem_cache_free(btrfs_free_space_cachep, entry);
+
 		spin_unlock(&ctl->tree_lock);
 
-		if (bytes >= minlen) {
-			struct btrfs_space_info *space_info;
-			int update = 0;
-
-			space_info = block_group->space_info;
-			spin_lock(&space_info->lock);
-			spin_lock(&block_group->lock);
-			if (!block_group->ro) {
-				block_group->reserved += bytes;
-				space_info->bytes_reserved += bytes;
-				update = 1;
-			}
-			spin_unlock(&block_group->lock);
-			spin_unlock(&space_info->lock);
-
-			ret = btrfs_error_discard_extent(fs_info->extent_root,
-							 start,
-							 bytes,
-							 &actually_trimmed);
-
-			btrfs_add_free_space(block_group, start, bytes);
-			if (update) {
-				spin_lock(&space_info->lock);
-				spin_lock(&block_group->lock);
-				if (block_group->ro)
-					space_info->bytes_readonly += bytes;
-				block_group->reserved -= bytes;
-				space_info->bytes_reserved -= bytes;
-				spin_unlock(&space_info->lock);
-				spin_unlock(&block_group->lock);
-			}
+		ret = do_trimming(block_group, total_trimmed, start, bytes,
+				  extent_start, extent_bytes);
+		if (ret)
+			break;
+next:
+		start += bytes;
 
-			if (ret)
-				break;
-			*trimmed += actually_trimmed;
+		if (fatal_signal_pending(current)) {
+			ret = -ERESTARTSYS;
+			break;
+		}
+
+		cond_resched();
+	}
+out:
+	return ret;
+}
+
+static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
+			u64 *total_trimmed, u64 start, u64 end, u64 minlen)
+{
+	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
+	struct btrfs_free_space *entry;
+	int ret = 0;
+	int ret2;
+	u64 bytes;
+	u64 offset = offset_to_bitmap(ctl, start);
+
+	while (offset < end) {
+		bool next_bitmap = false;
+
+		spin_lock(&ctl->tree_lock);
+
+		if (ctl->free_space < minlen) {
+			spin_unlock(&ctl->tree_lock);
+			break;
+		}
+
+		entry = tree_search_offset(ctl, offset, 1, 0);
+		if (!entry) {
+			spin_unlock(&ctl->tree_lock);
+			next_bitmap = true;
+			goto next;
+		}
+
+		bytes = minlen;
+		ret2 = search_bitmap(ctl, entry, &start, &bytes);
+		if (ret2 || start >= end) {
+			spin_unlock(&ctl->tree_lock);
+			next_bitmap = true;
+			goto next;
+		}
+
+		bytes = min(bytes, end - start);
+		if (bytes < minlen) {
+			spin_unlock(&ctl->tree_lock);
+			goto next;
+		}
+
+		bitmap_clear_bits(ctl, entry, start, bytes);
+		if (entry->bytes == 0)
+			free_bitmap(ctl, entry);
+
+		spin_unlock(&ctl->tree_lock);
+
+		ret = do_trimming(block_group, total_trimmed, start, bytes,
+				  start, bytes);
+		if (ret)
+			break;
+next:
+		if (next_bitmap) {
+			offset += BITS_PER_BITMAP * ctl->unit;
+		} else {
+			start += bytes;
+			if (start >= offset + BITS_PER_BITMAP * ctl->unit)
+				offset += BITS_PER_BITMAP * ctl->unit;
 		}
-		start += bytes;
-		bytes = 0;
 
 		if (fatal_signal_pending(current)) {
 			ret = -ERESTARTSYS;
@@ -2696,6 +2776,22 @@ int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
 	return ret;
 }
 
+int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
+			   u64 *trimmed, u64 start, u64 end, u64 minlen)
+{
+	int ret;
+
+	*trimmed = 0;
+
+	ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
+	if (ret)
+		return ret;
+
+	ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
+
+	return ret;
+}
+
 /*
  * Find the left-most item in the cache tree, and then return the
  * smallest inode number in the item.
diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index f8962a957d6..213ffa86ce1 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -438,6 +438,8 @@ int btrfs_save_ino_cache(struct btrfs_root *root,
 					  trans->bytes_reserved);
 	if (ret)
 		goto out;
+	trace_btrfs_space_reservation(root->fs_info, "ino_cache", (u64)trans,
+				      trans->bytes_reserved, 1);
 again:
 	inode = lookup_free_ino_inode(root, path);
 	if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
@@ -498,6 +500,8 @@ again:
 out_put:
 	iput(inode);
 out_release:
+	trace_btrfs_space_reservation(root->fs_info, "ino_cache", (u64)trans,
+				      trans->bytes_reserved, 0);
 	btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
 out:
 	trans->block_rsv = rsv;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 0a6b928813a..32214fe0f7e 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1944,19 +1944,35 @@ enum btrfs_orphan_cleanup_state {
 };
 
 /*
- * This is called in transaction commmit time. If there are no orphan
+ * This is called in transaction commit time. If there are no orphan
  * files in the subvolume, it removes orphan item and frees block_rsv
  * structure.
  */
 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
 			      struct btrfs_root *root)
 {
+	struct btrfs_block_rsv *block_rsv;
 	int ret;
 
 	if (!list_empty(&root->orphan_list) ||
 	    root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
 		return;
 
+	spin_lock(&root->orphan_lock);
+	if (!list_empty(&root->orphan_list)) {
+		spin_unlock(&root->orphan_lock);
+		return;
+	}
+
+	if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
+		spin_unlock(&root->orphan_lock);
+		return;
+	}
+
+	block_rsv = root->orphan_block_rsv;
+	root->orphan_block_rsv = NULL;
+	spin_unlock(&root->orphan_lock);
+
 	if (root->orphan_item_inserted &&
 	    btrfs_root_refs(&root->root_item) > 0) {
 		ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
@@ -1965,10 +1981,9 @@ void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
 		root->orphan_item_inserted = 0;
 	}
 
-	if (root->orphan_block_rsv) {
-		WARN_ON(root->orphan_block_rsv->size > 0);
-		btrfs_free_block_rsv(root, root->orphan_block_rsv);
-		root->orphan_block_rsv = NULL;
+	if (block_rsv) {
+		WARN_ON(block_rsv->size > 0);
+		btrfs_free_block_rsv(root, block_rsv);
 	}
 }
 
@@ -2224,14 +2239,7 @@ int btrfs_orphan_cleanup(struct btrfs_root *root)
 				continue;
 			}
 			nr_truncate++;
-			/*
-			 * Need to hold the imutex for reservation purposes, not
-			 * a huge deal here but I have a WARN_ON in
-			 * btrfs_delalloc_reserve_space to catch offenders.
-			 */
-			mutex_lock(&inode->i_mutex);
 			ret = btrfs_truncate(inode);
-			mutex_unlock(&inode->i_mutex);
 		} else {
 			nr_unlink++;
 		}
@@ -2845,7 +2853,7 @@ static void __unlink_end_trans(struct btrfs_trans_handle *trans,
 		BUG_ON(!root->fs_info->enospc_unlink);
 		root->fs_info->enospc_unlink = 0;
 	}
-	btrfs_end_transaction_throttle(trans, root);
+	btrfs_end_transaction(trans, root);
 }
 
 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
@@ -3009,7 +3017,6 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 	int pending_del_nr = 0;
 	int pending_del_slot = 0;
 	int extent_type = -1;
-	int encoding;
 	int ret;
 	int err = 0;
 	u64 ino = btrfs_ino(inode);
@@ -3059,7 +3066,6 @@ search_again:
 		leaf = path->nodes[0];
 		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 		found_type = btrfs_key_type(&found_key);
-		encoding = 0;
 
 		if (found_key.objectid != ino)
 			break;
@@ -3072,10 +3078,6 @@ search_again:
 			fi = btrfs_item_ptr(leaf, path->slots[0],
 					    struct btrfs_file_extent_item);
 			extent_type = btrfs_file_extent_type(leaf, fi);
-			encoding = btrfs_file_extent_compression(leaf, fi);
-			encoding |= btrfs_file_extent_encryption(leaf, fi);
-			encoding |= btrfs_file_extent_other_encoding(leaf, fi);
-
 			if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
 				item_end +=
 				    btrfs_file_extent_num_bytes(leaf, fi);
@@ -3103,7 +3105,7 @@ search_again:
 		if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
 			u64 num_dec;
 			extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
-			if (!del_item && !encoding) {
+			if (!del_item) {
 				u64 orig_num_bytes =
 					btrfs_file_extent_num_bytes(leaf, fi);
 				extent_num_bytes = new_size -
@@ -3179,7 +3181,7 @@ delete:
 			ret = btrfs_free_extent(trans, root, extent_start,
 						extent_num_bytes, 0,
 						btrfs_header_owner(leaf),
-						ino, extent_offset);
+						ino, extent_offset, 0);
 			BUG_ON(ret);
 		}
 
@@ -3434,7 +3436,7 @@ static int btrfs_setsize(struct inode *inode, loff_t newsize)
 		i_size_write(inode, newsize);
 		btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
 		ret = btrfs_update_inode(trans, root, inode);
-		btrfs_end_transaction_throttle(trans, root);
+		btrfs_end_transaction(trans, root);
 	} else {
 
 		/*
@@ -4412,8 +4414,8 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
 				     struct btrfs_root *root,
 				     struct inode *dir,
 				     const char *name, int name_len,
-				     u64 ref_objectid, u64 objectid, int mode,
-				     u64 *index)
+				     u64 ref_objectid, u64 objectid,
+				     umode_t mode, u64 *index)
 {
 	struct inode *inode;
 	struct btrfs_inode_item *inode_item;
@@ -4590,17 +4592,13 @@ static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
 	int err = btrfs_add_link(trans, dir, inode,
 				 dentry->d_name.name, dentry->d_name.len,
 				 backref, index);
-	if (!err) {
-		d_instantiate(dentry, inode);
-		return 0;
-	}
 	if (err > 0)
 		err = -EEXIST;
 	return err;
 }
 
 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
-			int mode, dev_t rdev)
+			umode_t mode, dev_t rdev)
 {
 	struct btrfs_trans_handle *trans;
 	struct btrfs_root *root = BTRFS_I(dir)->root;
@@ -4655,10 +4653,11 @@ static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
 	else {
 		init_special_inode(inode, inode->i_mode, rdev);
 		btrfs_update_inode(trans, root, inode);
+		d_instantiate(dentry, inode);
 	}
 out_unlock:
 	nr = trans->blocks_used;
-	btrfs_end_transaction_throttle(trans, root);
+	btrfs_end_transaction(trans, root);
 	btrfs_btree_balance_dirty(root, nr);
 	if (drop_inode) {
 		inode_dec_link_count(inode);
@@ -4668,7 +4667,7 @@ out_unlock:
 }
 
 static int btrfs_create(struct inode *dir, struct dentry *dentry,
-			int mode, struct nameidata *nd)
+			umode_t mode, struct nameidata *nd)
 {
 	struct btrfs_trans_handle *trans;
 	struct btrfs_root *root = BTRFS_I(dir)->root;
@@ -4722,10 +4721,11 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
 		inode->i_mapping->a_ops = &btrfs_aops;
 		inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
 		BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
+		d_instantiate(dentry, inode);
 	}
 out_unlock:
 	nr = trans->blocks_used;
-	btrfs_end_transaction_throttle(trans, root);
+	btrfs_end_transaction(trans, root);
 	if (drop_inode) {
 		inode_dec_link_count(inode);
 		iput(inode);
@@ -4779,11 +4779,12 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 		struct dentry *parent = dentry->d_parent;
 		err = btrfs_update_inode(trans, root, inode);
 		BUG_ON(err);
+		d_instantiate(dentry, inode);
 		btrfs_log_new_name(trans, inode, NULL, parent);
 	}
 
 	nr = trans->blocks_used;
-	btrfs_end_transaction_throttle(trans, root);
+	btrfs_end_transaction(trans, root);
 fail:
 	if (drop_inode) {
 		inode_dec_link_count(inode);
@@ -4793,7 +4794,7 @@ fail:
 	return err;
 }
 
-static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
 	struct inode *inode = NULL;
 	struct btrfs_trans_handle *trans;
@@ -4849,7 +4850,7 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 
 out_fail:
 	nr = trans->blocks_used;
-	btrfs_end_transaction_throttle(trans, root);
+	btrfs_end_transaction(trans, root);
 	if (drop_on_err)
 		iput(inode);
 	btrfs_btree_balance_dirty(root, nr);
@@ -5122,7 +5123,7 @@ again:
 			}
 			flush_dcache_page(page);
 		} else if (create && PageUptodate(page)) {
-			WARN_ON(1);
+			BUG();
 			if (!trans) {
 				kunmap(page);
 				free_extent_map(em);
@@ -6400,21 +6401,23 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 	unsigned long zero_start;
 	loff_t size;
 	int ret;
+	int reserved = 0;
 	u64 page_start;
 	u64 page_end;
 
-	/* Need this to keep space reservations serialized */
-	mutex_lock(&inode->i_mutex);
 	ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
-	mutex_unlock(&inode->i_mutex);
-	if (!ret)
+	if (!ret) {
 		ret = btrfs_update_time(vma->vm_file);
+		reserved = 1;
+	}
 	if (ret) {
 		if (ret == -ENOMEM)
 			ret = VM_FAULT_OOM;
 		else /* -ENOSPC, -EIO, etc */
 			ret = VM_FAULT_SIGBUS;
-		goto out;
+		if (reserved)
+			goto out;
+		goto out_noreserve;
 	}
 
 	ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
@@ -6495,8 +6498,9 @@ out_unlock:
 	if (!ret)
 		return VM_FAULT_LOCKED;
 	unlock_page(page);
-	btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
 out:
+	btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
+out_noreserve:
 	return ret;
 }
 
@@ -6669,7 +6673,7 @@ end_trans:
 			err = ret;
 
 		nr = trans->blocks_used;
-		ret = btrfs_end_transaction_throttle(trans, root);
+		ret = btrfs_end_transaction(trans, root);
 		btrfs_btree_balance_dirty(root, nr);
 	}
 
@@ -6750,6 +6754,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
 	extent_io_tree_init(&ei->io_tree, &inode->i_data);
 	extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
 	mutex_init(&ei->log_mutex);
+	mutex_init(&ei->delalloc_mutex);
 	btrfs_ordered_inode_tree_init(&ei->ordered_tree);
 	INIT_LIST_HEAD(&ei->i_orphan);
 	INIT_LIST_HEAD(&ei->delalloc_inodes);
@@ -6762,7 +6767,6 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
 static void btrfs_i_callback(struct rcu_head *head)
 {
 	struct inode *inode = container_of(head, struct inode, i_rcu);
-	INIT_LIST_HEAD(&inode->i_dentry);
 	kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
 }
 
@@ -7076,7 +7080,7 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 		btrfs_end_log_trans(root);
 	}
 out_fail:
-	btrfs_end_transaction_throttle(trans, root);
+	btrfs_end_transaction(trans, root);
 out_notrans:
 	if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
 		up_read(&root->fs_info->subvol_sem);
@@ -7245,8 +7249,10 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
 		drop_inode = 1;
 
 out_unlock:
+	if (!err)
+		d_instantiate(dentry, inode);
 	nr = trans->blocks_used;
-	btrfs_end_transaction_throttle(trans, root);
+	btrfs_end_transaction(trans, root);
 	if (drop_inode) {
 		inode_dec_link_count(inode);
 		iput(inode);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index c04f02c7d5b..03bb62a9ee2 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -176,6 +176,8 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 	struct btrfs_trans_handle *trans;
 	unsigned int flags, oldflags;
 	int ret;
+	u64 ip_oldflags;
+	unsigned int i_oldflags;
 
 	if (btrfs_root_readonly(root))
 		return -EROFS;
@@ -192,6 +194,9 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 
 	mutex_lock(&inode->i_mutex);
 
+	ip_oldflags = ip->flags;
+	i_oldflags = inode->i_flags;
+
 	flags = btrfs_mask_flags(inode->i_mode, flags);
 	oldflags = btrfs_flags_to_ioctl(ip->flags);
 	if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
@@ -201,7 +206,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 		}
 	}
 
-	ret = mnt_want_write(file->f_path.mnt);
+	ret = mnt_want_write_file(file);
 	if (ret)
 		goto out_unlock;
 
@@ -249,19 +254,24 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 		ip->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
 	}
 
-	trans = btrfs_join_transaction(root);
-	BUG_ON(IS_ERR(trans));
+	trans = btrfs_start_transaction(root, 1);
+	if (IS_ERR(trans)) {
+		ret = PTR_ERR(trans);
+		goto out_drop;
+	}
 
 	btrfs_update_iflags(inode);
 	inode->i_ctime = CURRENT_TIME;
 	ret = btrfs_update_inode(trans, root, inode);
-	BUG_ON(ret);
 
 	btrfs_end_transaction(trans, root);
+ out_drop:
+	if (ret) {
+		ip->flags = ip_oldflags;
+		inode->i_flags = i_oldflags;
+	}
 
-	mnt_drop_write(file->f_path.mnt);
-
-	ret = 0;
+	mnt_drop_write_file(file);
  out_unlock:
 	mutex_unlock(&inode->i_mutex);
 	return ret;
@@ -276,14 +286,13 @@ static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
 
 static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
 {
-	struct btrfs_root *root = fdentry(file)->d_sb->s_fs_info;
-	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_fs_info *fs_info = btrfs_sb(fdentry(file)->d_sb);
 	struct btrfs_device *device;
 	struct request_queue *q;
 	struct fstrim_range range;
 	u64 minlen = ULLONG_MAX;
 	u64 num_devices = 0;
-	u64 total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
+	u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
 	int ret;
 
 	if (!capable(CAP_SYS_ADMIN))
@@ -312,7 +321,7 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
 
 	range.len = min(range.len, total_bytes - range.start);
 	range.minlen = max(range.minlen, minlen);
-	ret = btrfs_trim_fs(root, &range);
+	ret = btrfs_trim_fs(fs_info->tree_root, &range);
 	if (ret < 0)
 		return ret;
 
@@ -358,7 +367,7 @@ static noinline int create_subvol(struct btrfs_root *root,
 		return PTR_ERR(trans);
 
 	leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
-				      0, objectid, NULL, 0, 0, 0);
+				      0, objectid, NULL, 0, 0, 0, 0);
 	if (IS_ERR(leaf)) {
 		ret = PTR_ERR(leaf);
 		goto fail;
@@ -858,10 +867,8 @@ static int cluster_pages_for_defrag(struct inode *inode,
 		return 0;
 	file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
 
-	mutex_lock(&inode->i_mutex);
 	ret = btrfs_delalloc_reserve_space(inode,
 					   num_pages << PAGE_CACHE_SHIFT);
-	mutex_unlock(&inode->i_mutex);
 	if (ret)
 		return ret;
 again:
@@ -1058,7 +1065,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
 		i = range->start >> PAGE_CACHE_SHIFT;
 	}
 	if (!max_to_defrag)
-		max_to_defrag = last_index;
+		max_to_defrag = last_index + 1;
 
 	/*
 	 * make writeback starts from i, so the defrag range can be
@@ -1203,13 +1210,21 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
+	mutex_lock(&root->fs_info->volume_mutex);
+	if (root->fs_info->balance_ctl) {
+		printk(KERN_INFO "btrfs: balance in progress\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
 	vol_args = memdup_user(arg, sizeof(*vol_args));
-	if (IS_ERR(vol_args))
-		return PTR_ERR(vol_args);
+	if (IS_ERR(vol_args)) {
+		ret = PTR_ERR(vol_args);
+		goto out;
+	}
 
 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 
-	mutex_lock(&root->fs_info->volume_mutex);
 	sizestr = vol_args->name;
 	devstr = strchr(sizestr, ':');
 	if (devstr) {
@@ -1226,7 +1241,7 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
 		printk(KERN_INFO "btrfs: resizer unable to find device %llu\n",
 		       (unsigned long long)devid);
 		ret = -EINVAL;
-		goto out_unlock;
+		goto out_free;
 	}
 	if (!strcmp(sizestr, "max"))
 		new_size = device->bdev->bd_inode->i_size;
@@ -1241,7 +1256,7 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
 		new_size = memparse(sizestr, NULL);
 		if (new_size == 0) {
 			ret = -EINVAL;
-			goto out_unlock;
+			goto out_free;
 		}
 	}
 
@@ -1250,7 +1265,7 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
 	if (mod < 0) {
 		if (new_size > old_size) {
 			ret = -EINVAL;
-			goto out_unlock;
+			goto out_free;
 		}
 		new_size = old_size - new_size;
 	} else if (mod > 0) {
@@ -1259,11 +1274,11 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
 
 	if (new_size < 256 * 1024 * 1024) {
 		ret = -EINVAL;
-		goto out_unlock;
+		goto out_free;
 	}
 	if (new_size > device->bdev->bd_inode->i_size) {
 		ret = -EFBIG;
-		goto out_unlock;
+		goto out_free;
 	}
 
 	do_div(new_size, root->sectorsize);
@@ -1276,7 +1291,7 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
 		trans = btrfs_start_transaction(root, 0);
 		if (IS_ERR(trans)) {
 			ret = PTR_ERR(trans);
-			goto out_unlock;
+			goto out_free;
 		}
 		ret = btrfs_grow_device(trans, device, new_size);
 		btrfs_commit_transaction(trans, root);
@@ -1284,9 +1299,10 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
 		ret = btrfs_shrink_device(device, new_size);
 	}
 
-out_unlock:
-	mutex_unlock(&root->fs_info->volume_mutex);
+out_free:
 	kfree(vol_args);
+out:
+	mutex_unlock(&root->fs_info->volume_mutex);
 	return ret;
 }
 
@@ -1855,7 +1871,7 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
 		goto out;
 	}
 
-	err = mnt_want_write(file->f_path.mnt);
+	err = mnt_want_write_file(file);
 	if (err)
 		goto out;
 
@@ -1971,7 +1987,7 @@ out_dput:
 	dput(dentry);
 out_unlock_dir:
 	mutex_unlock(&dir->i_mutex);
-	mnt_drop_write(file->f_path.mnt);
+	mnt_drop_write_file(file);
 out:
 	kfree(vol_args);
 	return err;
@@ -1987,7 +2003,7 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
 	if (btrfs_root_readonly(root))
 		return -EROFS;
 
-	ret = mnt_want_write(file->f_path.mnt);
+	ret = mnt_want_write_file(file);
 	if (ret)
 		return ret;
 
@@ -2040,7 +2056,7 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
 		ret = -EINVAL;
 	}
 out:
-	mnt_drop_write(file->f_path.mnt);
+	mnt_drop_write_file(file);
 	return ret;
 }
 
@@ -2052,14 +2068,25 @@ static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
+	mutex_lock(&root->fs_info->volume_mutex);
+	if (root->fs_info->balance_ctl) {
+		printk(KERN_INFO "btrfs: balance in progress\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
 	vol_args = memdup_user(arg, sizeof(*vol_args));
-	if (IS_ERR(vol_args))
-		return PTR_ERR(vol_args);
+	if (IS_ERR(vol_args)) {
+		ret = PTR_ERR(vol_args);
+		goto out;
+	}
 
 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 	ret = btrfs_init_new_device(root, vol_args->name);
 
 	kfree(vol_args);
+out:
+	mutex_unlock(&root->fs_info->volume_mutex);
 	return ret;
 }
 
@@ -2074,14 +2101,25 @@ static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
 	if (root->fs_info->sb->s_flags & MS_RDONLY)
 		return -EROFS;
 
+	mutex_lock(&root->fs_info->volume_mutex);
+	if (root->fs_info->balance_ctl) {
+		printk(KERN_INFO "btrfs: balance in progress\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
 	vol_args = memdup_user(arg, sizeof(*vol_args));
-	if (IS_ERR(vol_args))
-		return PTR_ERR(vol_args);
+	if (IS_ERR(vol_args)) {
+		ret = PTR_ERR(vol_args);
+		goto out;
+	}
 
 	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 	ret = btrfs_rm_device(root, vol_args->name);
 
 	kfree(vol_args);
+out:
+	mutex_unlock(&root->fs_info->volume_mutex);
 	return ret;
 }
 
@@ -2195,7 +2233,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 	if (btrfs_root_readonly(root))
 		return -EROFS;
 
-	ret = mnt_want_write(file->f_path.mnt);
+	ret = mnt_want_write_file(file);
 	if (ret)
 		return ret;
 
@@ -2427,7 +2465,8 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 							disko, diskl, 0,
 							root->root_key.objectid,
 							btrfs_ino(inode),
-							new_key.offset - datao);
+							new_key.offset - datao,
+							0);
 					BUG_ON(ret);
 				}
 			} else if (type == BTRFS_FILE_EXTENT_INLINE) {
@@ -2510,7 +2549,7 @@ out_unlock:
 out_fput:
 	fput(src_file);
 out_drop_write:
-	mnt_drop_write(file->f_path.mnt);
+	mnt_drop_write_file(file);
 	return ret;
 }
 
@@ -2549,7 +2588,7 @@ static long btrfs_ioctl_trans_start(struct file *file)
 	if (btrfs_root_readonly(root))
 		goto out;
 
-	ret = mnt_want_write(file->f_path.mnt);
+	ret = mnt_want_write_file(file);
 	if (ret)
 		goto out;
 
@@ -2565,7 +2604,7 @@ static long btrfs_ioctl_trans_start(struct file *file)
 
 out_drop:
 	atomic_dec(&root->fs_info->open_ioctl_trans);
-	mnt_drop_write(file->f_path.mnt);
+	mnt_drop_write_file(file);
 out:
 	return ret;
 }
@@ -2800,7 +2839,7 @@ long btrfs_ioctl_trans_end(struct file *file)
 
 	atomic_dec(&root->fs_info->open_ioctl_trans);
 
-	mnt_drop_write(file->f_path.mnt);
+	mnt_drop_write_file(file);
 	return 0;
 }
 
@@ -2977,7 +3016,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_root *root,
 {
 	int ret = 0;
 	int size;
-	u64 extent_offset;
+	u64 extent_item_pos;
 	struct btrfs_ioctl_logical_ino_args *loi;
 	struct btrfs_data_container *inodes = NULL;
 	struct btrfs_path *path = NULL;
@@ -3008,15 +3047,17 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_root *root,
 	}
 
 	ret = extent_from_logical(root->fs_info, loi->logical, path, &key);
+	btrfs_release_path(path);
 
 	if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK)
 		ret = -ENOENT;
 	if (ret < 0)
 		goto out;
 
-	extent_offset = loi->logical - key.objectid;
+	extent_item_pos = loi->logical - key.objectid;
 	ret = iterate_extent_inodes(root->fs_info, path, key.objectid,
-					extent_offset, build_ino_list, inodes);
+					extent_item_pos, build_ino_list,
+					inodes);
 
 	if (ret < 0)
 		goto out;
@@ -3034,6 +3075,163 @@ out:
 	return ret;
 }
 
+void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
+			       struct btrfs_ioctl_balance_args *bargs)
+{
+	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
+
+	bargs->flags = bctl->flags;
+
+	if (atomic_read(&fs_info->balance_running))
+		bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
+	if (atomic_read(&fs_info->balance_pause_req))
+		bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
+	if (atomic_read(&fs_info->balance_cancel_req))
+		bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
+
+	memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
+	memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
+	memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
+
+	if (lock) {
+		spin_lock(&fs_info->balance_lock);
+		memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
+		spin_unlock(&fs_info->balance_lock);
+	} else {
+		memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
+	}
+}
+
+static long btrfs_ioctl_balance(struct btrfs_root *root, void __user *arg)
+{
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_ioctl_balance_args *bargs;
+	struct btrfs_balance_control *bctl;
+	int ret;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (fs_info->sb->s_flags & MS_RDONLY)
+		return -EROFS;
+
+	mutex_lock(&fs_info->volume_mutex);
+	mutex_lock(&fs_info->balance_mutex);
+
+	if (arg) {
+		bargs = memdup_user(arg, sizeof(*bargs));
+		if (IS_ERR(bargs)) {
+			ret = PTR_ERR(bargs);
+			goto out;
+		}
+
+		if (bargs->flags & BTRFS_BALANCE_RESUME) {
+			if (!fs_info->balance_ctl) {
+				ret = -ENOTCONN;
+				goto out_bargs;
+			}
+
+			bctl = fs_info->balance_ctl;
+			spin_lock(&fs_info->balance_lock);
+			bctl->flags |= BTRFS_BALANCE_RESUME;
+			spin_unlock(&fs_info->balance_lock);
+
+			goto do_balance;
+		}
+	} else {
+		bargs = NULL;
+	}
+
+	if (fs_info->balance_ctl) {
+		ret = -EINPROGRESS;
+		goto out_bargs;
+	}
+
+	bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
+	if (!bctl) {
+		ret = -ENOMEM;
+		goto out_bargs;
+	}
+
+	bctl->fs_info = fs_info;
+	if (arg) {
+		memcpy(&bctl->data, &bargs->data, sizeof(bctl->data));
+		memcpy(&bctl->meta, &bargs->meta, sizeof(bctl->meta));
+		memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
+
+		bctl->flags = bargs->flags;
+	} else {
+		/* balance everything - no filters */
+		bctl->flags |= BTRFS_BALANCE_TYPE_MASK;
+	}
+
+do_balance:
+	ret = btrfs_balance(bctl, bargs);
+	/*
+	 * bctl is freed in __cancel_balance or in free_fs_info if
+	 * restriper was paused all the way until unmount
+	 */
+	if (arg) {
+		if (copy_to_user(arg, bargs, sizeof(*bargs)))
+			ret = -EFAULT;
+	}
+
+out_bargs:
+	kfree(bargs);
+out:
+	mutex_unlock(&fs_info->balance_mutex);
+	mutex_unlock(&fs_info->volume_mutex);
+	return ret;
+}
+
+static long btrfs_ioctl_balance_ctl(struct btrfs_root *root, int cmd)
+{
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	switch (cmd) {
+	case BTRFS_BALANCE_CTL_PAUSE:
+		return btrfs_pause_balance(root->fs_info);
+	case BTRFS_BALANCE_CTL_CANCEL:
+		return btrfs_cancel_balance(root->fs_info);
+	}
+
+	return -EINVAL;
+}
+
+static long btrfs_ioctl_balance_progress(struct btrfs_root *root,
+					 void __user *arg)
+{
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_ioctl_balance_args *bargs;
+	int ret = 0;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	mutex_lock(&fs_info->balance_mutex);
+	if (!fs_info->balance_ctl) {
+		ret = -ENOTCONN;
+		goto out;
+	}
+
+	bargs = kzalloc(sizeof(*bargs), GFP_NOFS);
+	if (!bargs) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	update_ioctl_balance_args(fs_info, 1, bargs);
+
+	if (copy_to_user(arg, bargs, sizeof(*bargs)))
+		ret = -EFAULT;
+
+	kfree(bargs);
+out:
+	mutex_unlock(&fs_info->balance_mutex);
+	return ret;
+}
+
 long btrfs_ioctl(struct file *file, unsigned int
 		cmd, unsigned long arg)
 {
@@ -3078,7 +3276,7 @@ long btrfs_ioctl(struct file *file, unsigned int
 	case BTRFS_IOC_DEV_INFO:
 		return btrfs_ioctl_dev_info(root, argp);
 	case BTRFS_IOC_BALANCE:
-		return btrfs_balance(root->fs_info->dev_root);
+		return btrfs_ioctl_balance(root, NULL);
 	case BTRFS_IOC_CLONE:
 		return btrfs_ioctl_clone(file, arg, 0, 0, 0);
 	case BTRFS_IOC_CLONE_RANGE:
@@ -3110,6 +3308,12 @@ long btrfs_ioctl(struct file *file, unsigned int
 		return btrfs_ioctl_scrub_cancel(root, argp);
 	case BTRFS_IOC_SCRUB_PROGRESS:
 		return btrfs_ioctl_scrub_progress(root, argp);
+	case BTRFS_IOC_BALANCE_V2:
+		return btrfs_ioctl_balance(root, argp);
+	case BTRFS_IOC_BALANCE_CTL:
+		return btrfs_ioctl_balance_ctl(root, arg);
+	case BTRFS_IOC_BALANCE_PROGRESS:
+		return btrfs_ioctl_balance_progress(root, argp);
 	}
 
 	return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 252ae9915de..4f69028a68c 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -109,6 +109,55 @@ struct btrfs_ioctl_fs_info_args {
 	__u64 reserved[124];			/* pad to 1k */
 };
 
+/* balance control ioctl modes */
+#define BTRFS_BALANCE_CTL_PAUSE		1
+#define BTRFS_BALANCE_CTL_CANCEL	2
+
+/*
+ * this is packed, because it should be exactly the same as its disk
+ * byte order counterpart (struct btrfs_disk_balance_args)
+ */
+struct btrfs_balance_args {
+	__u64 profiles;
+	__u64 usage;
+	__u64 devid;
+	__u64 pstart;
+	__u64 pend;
+	__u64 vstart;
+	__u64 vend;
+
+	__u64 target;
+
+	__u64 flags;
+
+	__u64 unused[8];
+} __attribute__ ((__packed__));
+
+/* report balance progress to userspace */
+struct btrfs_balance_progress {
+	__u64 expected;		/* estimated # of chunks that will be
+				 * relocated to fulfill the request */
+	__u64 considered;	/* # of chunks we have considered so far */
+	__u64 completed;	/* # of chunks relocated so far */
+};
+
+#define BTRFS_BALANCE_STATE_RUNNING	(1ULL << 0)
+#define BTRFS_BALANCE_STATE_PAUSE_REQ	(1ULL << 1)
+#define BTRFS_BALANCE_STATE_CANCEL_REQ	(1ULL << 2)
+
+struct btrfs_ioctl_balance_args {
+	__u64 flags;				/* in/out */
+	__u64 state;				/* out */
+
+	struct btrfs_balance_args data;		/* in/out */
+	struct btrfs_balance_args meta;		/* in/out */
+	struct btrfs_balance_args sys;		/* in/out */
+
+	struct btrfs_balance_progress stat;	/* out */
+
+	__u64 unused[72];			/* pad to 1k */
+};
+
 #define BTRFS_INO_LOOKUP_PATH_MAX 4080
 struct btrfs_ioctl_ino_lookup_args {
 	__u64 treeid;
@@ -272,6 +321,11 @@ struct btrfs_ioctl_logical_ino_args {
 				 struct btrfs_ioctl_dev_info_args)
 #define BTRFS_IOC_FS_INFO _IOR(BTRFS_IOCTL_MAGIC, 31, \
 			       struct btrfs_ioctl_fs_info_args)
+#define BTRFS_IOC_BALANCE_V2 _IOWR(BTRFS_IOCTL_MAGIC, 32, \
+				   struct btrfs_ioctl_balance_args)
+#define BTRFS_IOC_BALANCE_CTL _IOW(BTRFS_IOCTL_MAGIC, 33, int)
+#define BTRFS_IOC_BALANCE_PROGRESS _IOR(BTRFS_IOCTL_MAGIC, 34, \
+					struct btrfs_ioctl_balance_args)
 #define BTRFS_IOC_INO_PATHS _IOWR(BTRFS_IOCTL_MAGIC, 35, \
 					struct btrfs_ioctl_ino_path_args)
 #define BTRFS_IOC_LOGICAL_INO _IOWR(BTRFS_IOCTL_MAGIC, 36, \
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index d77b67c4b27..5e178d8f716 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -33,6 +33,14 @@ void btrfs_assert_tree_read_locked(struct extent_buffer *eb);
  */
 void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw)
 {
+	if (eb->lock_nested) {
+		read_lock(&eb->lock);
+		if (eb->lock_nested && current->pid == eb->lock_owner) {
+			read_unlock(&eb->lock);
+			return;
+		}
+		read_unlock(&eb->lock);
+	}
 	if (rw == BTRFS_WRITE_LOCK) {
 		if (atomic_read(&eb->blocking_writers) == 0) {
 			WARN_ON(atomic_read(&eb->spinning_writers) != 1);
@@ -57,6 +65,14 @@ void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw)
  */
 void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw)
 {
+	if (eb->lock_nested) {
+		read_lock(&eb->lock);
+		if (&eb->lock_nested && current->pid == eb->lock_owner) {
+			read_unlock(&eb->lock);
+			return;
+		}
+		read_unlock(&eb->lock);
+	}
 	if (rw == BTRFS_WRITE_LOCK_BLOCKING) {
 		BUG_ON(atomic_read(&eb->blocking_writers) != 1);
 		write_lock(&eb->lock);
@@ -81,12 +97,25 @@ void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw)
 void btrfs_tree_read_lock(struct extent_buffer *eb)
 {
 again:
+	read_lock(&eb->lock);
+	if (atomic_read(&eb->blocking_writers) &&
+	    current->pid == eb->lock_owner) {
+		/*
+		 * This extent is already write-locked by our thread. We allow
+		 * an additional read lock to be added because it's for the same
+		 * thread. btrfs_find_all_roots() depends on this as it may be
+		 * called on a partly (write-)locked tree.
+		 */
+		BUG_ON(eb->lock_nested);
+		eb->lock_nested = 1;
+		read_unlock(&eb->lock);
+		return;
+	}
+	read_unlock(&eb->lock);
 	wait_event(eb->write_lock_wq, atomic_read(&eb->blocking_writers) == 0);
 	read_lock(&eb->lock);
 	if (atomic_read(&eb->blocking_writers)) {
 		read_unlock(&eb->lock);
-		wait_event(eb->write_lock_wq,
-			   atomic_read(&eb->blocking_writers) == 0);
 		goto again;
 	}
 	atomic_inc(&eb->read_locks);
@@ -129,6 +158,7 @@ int btrfs_try_tree_write_lock(struct extent_buffer *eb)
 	}
 	atomic_inc(&eb->write_locks);
 	atomic_inc(&eb->spinning_writers);
+	eb->lock_owner = current->pid;
 	return 1;
 }
 
@@ -137,6 +167,15 @@ int btrfs_try_tree_write_lock(struct extent_buffer *eb)
  */
 void btrfs_tree_read_unlock(struct extent_buffer *eb)
 {
+	if (eb->lock_nested) {
+		read_lock(&eb->lock);
+		if (eb->lock_nested && current->pid == eb->lock_owner) {
+			eb->lock_nested = 0;
+			read_unlock(&eb->lock);
+			return;
+		}
+		read_unlock(&eb->lock);
+	}
 	btrfs_assert_tree_read_locked(eb);
 	WARN_ON(atomic_read(&eb->spinning_readers) == 0);
 	atomic_dec(&eb->spinning_readers);
@@ -149,6 +188,15 @@ void btrfs_tree_read_unlock(struct extent_buffer *eb)
  */
 void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb)
 {
+	if (eb->lock_nested) {
+		read_lock(&eb->lock);
+		if (eb->lock_nested && current->pid == eb->lock_owner) {
+			eb->lock_nested = 0;
+			read_unlock(&eb->lock);
+			return;
+		}
+		read_unlock(&eb->lock);
+	}
 	btrfs_assert_tree_read_locked(eb);
 	WARN_ON(atomic_read(&eb->blocking_readers) == 0);
 	if (atomic_dec_and_test(&eb->blocking_readers))
@@ -181,6 +229,7 @@ again:
 	WARN_ON(atomic_read(&eb->spinning_writers));
 	atomic_inc(&eb->spinning_writers);
 	atomic_inc(&eb->write_locks);
+	eb->lock_owner = current->pid;
 	return 0;
 }
 
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index cfb55434a46..8c1aae2c845 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1604,12 +1604,12 @@ int replace_file_extents(struct btrfs_trans_handle *trans,
 		ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
 					   num_bytes, parent,
 					   btrfs_header_owner(leaf),
-					   key.objectid, key.offset);
+					   key.objectid, key.offset, 1);
 		BUG_ON(ret);
 
 		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 					parent, btrfs_header_owner(leaf),
-					key.objectid, key.offset);
+					key.objectid, key.offset, 1);
 		BUG_ON(ret);
 	}
 	if (dirty)
@@ -1778,21 +1778,23 @@ again:
 
 		ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
 					path->nodes[level]->start,
-					src->root_key.objectid, level - 1, 0);
+					src->root_key.objectid, level - 1, 0,
+					1);
 		BUG_ON(ret);
 		ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
 					0, dest->root_key.objectid, level - 1,
-					0);
+					0, 1);
 		BUG_ON(ret);
 
 		ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
 					path->nodes[level]->start,
-					src->root_key.objectid, level - 1, 0);
+					src->root_key.objectid, level - 1, 0,
+					1);
 		BUG_ON(ret);
 
 		ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
 					0, dest->root_key.objectid, level - 1,
-					0);
+					0, 1);
 		BUG_ON(ret);
 
 		btrfs_unlock_up_safe(path, 0);
@@ -2244,7 +2246,7 @@ again:
 		} else {
 			list_del_init(&reloc_root->root_list);
 		}
-		btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0);
+		btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
 	}
 
 	if (found) {
@@ -2558,7 +2560,7 @@ static int do_relocation(struct btrfs_trans_handle *trans,
 						node->eb->start, blocksize,
 						upper->eb->start,
 						btrfs_header_owner(upper->eb),
-						node->level, 0);
+						node->level, 0, 1);
 			BUG_ON(ret);
 
 			ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
@@ -2947,9 +2949,7 @@ static int relocate_file_extent_cluster(struct inode *inode,
 	index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
 	last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
 	while (index <= last_index) {
-		mutex_lock(&inode->i_mutex);
 		ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
-		mutex_unlock(&inode->i_mutex);
 		if (ret)
 			goto out;
 
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index ddf2c90d3fc..9770cc5bfb7 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -25,6 +25,7 @@
 #include "transaction.h"
 #include "backref.h"
 #include "extent_io.h"
+#include "check-integrity.h"
 
 /*
  * This is only the first step towards a full-features scrub. It reads all
@@ -309,7 +310,7 @@ static void scrub_print_warning(const char *errstr, struct scrub_bio *sbio,
 	u8 ref_level;
 	unsigned long ptr = 0;
 	const int bufsize = 4096;
-	u64 extent_offset;
+	u64 extent_item_pos;
 
 	path = btrfs_alloc_path();
 
@@ -329,12 +330,13 @@ static void scrub_print_warning(const char *errstr, struct scrub_bio *sbio,
 	if (ret < 0)
 		goto out;
 
-	extent_offset = swarn.logical - found_key.objectid;
+	extent_item_pos = swarn.logical - found_key.objectid;
 	swarn.extent_item_size = found_key.offset;
 
 	eb = path->nodes[0];
 	ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
 	item_size = btrfs_item_size_nr(eb, path->slots[0]);
+	btrfs_release_path(path);
 
 	if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
 		do {
@@ -351,7 +353,7 @@ static void scrub_print_warning(const char *errstr, struct scrub_bio *sbio,
 	} else {
 		swarn.path = path;
 		iterate_extent_inodes(fs_info, path, found_key.objectid,
-					extent_offset,
+					extent_item_pos,
 					scrub_print_warning_inode, &swarn);
 	}
 
@@ -732,7 +734,7 @@ static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
 	bio_add_page(bio, page, PAGE_SIZE, 0);
 	bio->bi_end_io = scrub_fixup_end_io;
 	bio->bi_private = &complete;
-	submit_bio(rw, bio);
+	btrfsic_submit_bio(rw, bio);
 
 	/* this will also unplug the queue */
 	wait_for_completion(&complete);
@@ -958,7 +960,7 @@ static int scrub_submit(struct scrub_dev *sdev)
 	sdev->curr = -1;
 	atomic_inc(&sdev->in_flight);
 
-	submit_bio(READ, sbio->bio);
+	btrfsic_submit_bio(READ, sbio->bio);
 
 	return 0;
 }
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 200f63bc667..3ce97b217cb 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -40,7 +40,6 @@
 #include <linux/magic.h>
 #include <linux/slab.h>
 #include <linux/cleancache.h>
-#include <linux/mnt_namespace.h>
 #include <linux/ratelimit.h>
 #include "compat.h"
 #include "delayed-inode.h"
@@ -148,13 +147,13 @@ void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
 
 static void btrfs_put_super(struct super_block *sb)
 {
-	struct btrfs_root *root = btrfs_sb(sb);
-	int ret;
-
-	ret = close_ctree(root);
-	sb->s_fs_info = NULL;
-
-	(void)ret; /* FIXME: need to fix VFS to return error? */
+	(void)close_ctree(btrfs_sb(sb)->tree_root);
+	/* FIXME: need to fix VFS to return error? */
+	/* AV: return it _where_?  ->put_super() can be triggered by any number
+	 * of async events, up to and including delivery of SIGKILL to the
+	 * last process that kept it busy.  Or segfault in the aforementioned
+	 * process...  Whom would you report that to?
+	 */
 }
 
 enum {
@@ -164,8 +163,11 @@ enum {
 	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 	Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
-	Opt_enospc_debug, Opt_subvolrootid, Opt_defrag,
-	Opt_inode_cache, Opt_no_space_cache, Opt_recovery, Opt_err,
+	Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
+	Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
+	Opt_check_integrity, Opt_check_integrity_including_extent_data,
+	Opt_check_integrity_print_mask,
+	Opt_err,
 };
 
 static match_table_t tokens = {
@@ -200,6 +202,10 @@ static match_table_t tokens = {
 	{Opt_inode_cache, "inode_cache"},
 	{Opt_no_space_cache, "nospace_cache"},
 	{Opt_recovery, "recovery"},
+	{Opt_skip_balance, "skip_balance"},
+	{Opt_check_integrity, "check_int"},
+	{Opt_check_integrity_including_extent_data, "check_int_data"},
+	{Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
 	{Opt_err, NULL},
 };
 
@@ -398,6 +404,40 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
 			printk(KERN_INFO "btrfs: enabling auto recovery");
 			btrfs_set_opt(info->mount_opt, RECOVERY);
 			break;
+		case Opt_skip_balance:
+			btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
+			break;
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+		case Opt_check_integrity_including_extent_data:
+			printk(KERN_INFO "btrfs: enabling check integrity"
+			       " including extent data\n");
+			btrfs_set_opt(info->mount_opt,
+				      CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
+			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
+			break;
+		case Opt_check_integrity:
+			printk(KERN_INFO "btrfs: enabling check integrity\n");
+			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
+			break;
+		case Opt_check_integrity_print_mask:
+			intarg = 0;
+			match_int(&args[0], &intarg);
+			if (intarg) {
+				info->check_integrity_print_mask = intarg;
+				printk(KERN_INFO "btrfs:"
+				       " check_integrity_print_mask 0x%x\n",
+				       info->check_integrity_print_mask);
+			}
+			break;
+#else
+		case Opt_check_integrity_including_extent_data:
+		case Opt_check_integrity:
+		case Opt_check_integrity_print_mask:
+			printk(KERN_ERR "btrfs: support for check_integrity*"
+			       " not compiled in!\n");
+			ret = -EINVAL;
+			goto out;
+#endif
 		case Opt_err:
 			printk(KERN_INFO "btrfs: unrecognized mount option "
 			       "'%s'\n", p);
@@ -501,7 +541,8 @@ out:
 static struct dentry *get_default_root(struct super_block *sb,
 				       u64 subvol_objectid)
 {
-	struct btrfs_root *root = sb->s_fs_info;
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	struct btrfs_root *root = fs_info->tree_root;
 	struct btrfs_root *new_root;
 	struct btrfs_dir_item *di;
 	struct btrfs_path *path;
@@ -531,7 +572,7 @@ static struct dentry *get_default_root(struct super_block *sb,
 	 * will mount by default if we haven't been given a specific subvolume
 	 * to mount.
 	 */
-	dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
+	dir_id = btrfs_super_root_dir(fs_info->super_copy);
 	di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
 	if (IS_ERR(di)) {
 		btrfs_free_path(path);
@@ -545,7 +586,7 @@ static struct dentry *get_default_root(struct super_block *sb,
 		 */
 		btrfs_free_path(path);
 		dir_id = BTRFS_FIRST_FREE_OBJECTID;
-		new_root = root->fs_info->fs_root;
+		new_root = fs_info->fs_root;
 		goto setup_root;
 	}
 
@@ -553,7 +594,7 @@ static struct dentry *get_default_root(struct super_block *sb,
 	btrfs_free_path(path);
 
 find_root:
-	new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
+	new_root = btrfs_read_fs_root_no_name(fs_info, &location);
 	if (IS_ERR(new_root))
 		return ERR_CAST(new_root);
 
@@ -589,7 +630,7 @@ static int btrfs_fill_super(struct super_block *sb,
 {
 	struct inode *inode;
 	struct dentry *root_dentry;
-	struct btrfs_root *tree_root;
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 	struct btrfs_key key;
 	int err;
 
@@ -604,18 +645,16 @@ static int btrfs_fill_super(struct super_block *sb,
 	sb->s_flags |= MS_POSIXACL;
 #endif
 
-	tree_root = open_ctree(sb, fs_devices, (char *)data);
-
-	if (IS_ERR(tree_root)) {
+	err = open_ctree(sb, fs_devices, (char *)data);
+	if (err) {
 		printk("btrfs: open_ctree failed\n");
-		return PTR_ERR(tree_root);
+		return err;
 	}
-	sb->s_fs_info = tree_root;
 
 	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 	key.type = BTRFS_INODE_ITEM_KEY;
 	key.offset = 0;
-	inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL);
+	inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
 	if (IS_ERR(inode)) {
 		err = PTR_ERR(inode);
 		goto fail_close;
@@ -632,23 +671,25 @@ static int btrfs_fill_super(struct super_block *sb,
 
 	save_mount_options(sb, data);
 	cleancache_init_fs(sb);
+	sb->s_flags |= MS_ACTIVE;
 	return 0;
 
 fail_close:
-	close_ctree(tree_root);
+	close_ctree(fs_info->tree_root);
 	return err;
 }
 
 int btrfs_sync_fs(struct super_block *sb, int wait)
 {
 	struct btrfs_trans_handle *trans;
-	struct btrfs_root *root = btrfs_sb(sb);
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	struct btrfs_root *root = fs_info->tree_root;
 	int ret;
 
 	trace_btrfs_sync_fs(wait);
 
 	if (!wait) {
-		filemap_flush(root->fs_info->btree_inode->i_mapping);
+		filemap_flush(fs_info->btree_inode->i_mapping);
 		return 0;
 	}
 
@@ -662,10 +703,10 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
 	return ret;
 }
 
-static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
+static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
 {
-	struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
-	struct btrfs_fs_info *info = root->fs_info;
+	struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
+	struct btrfs_root *root = info->tree_root;
 	char *compress_type;
 
 	if (btrfs_test_opt(root, DEGRADED))
@@ -723,28 +764,25 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 		seq_puts(seq, ",autodefrag");
 	if (btrfs_test_opt(root, INODE_MAP_CACHE))
 		seq_puts(seq, ",inode_cache");
+	if (btrfs_test_opt(root, SKIP_BALANCE))
+		seq_puts(seq, ",skip_balance");
 	return 0;
 }
 
 static int btrfs_test_super(struct super_block *s, void *data)
 {
-	struct btrfs_root *test_root = data;
-	struct btrfs_root *root = btrfs_sb(s);
+	struct btrfs_fs_info *p = data;
+	struct btrfs_fs_info *fs_info = btrfs_sb(s);
 
-	/*
-	 * If this super block is going away, return false as it
-	 * can't match as an existing super block.
-	 */
-	if (!atomic_read(&s->s_active))
-		return 0;
-	return root->fs_info->fs_devices == test_root->fs_info->fs_devices;
+	return fs_info->fs_devices == p->fs_devices;
 }
 
 static int btrfs_set_super(struct super_block *s, void *data)
 {
-	s->s_fs_info = data;
-
-	return set_anon_super(s, data);
+	int err = set_anon_super(s, data);
+	if (!err)
+		s->s_fs_info = data;
+	return err;
 }
 
 /*
@@ -904,12 +942,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 	if (!fs_info)
 		return ERR_PTR(-ENOMEM);
 
-	fs_info->tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
-	if (!fs_info->tree_root) {
-		error = -ENOMEM;
-		goto error_fs_info;
-	}
-	fs_info->tree_root->fs_info = fs_info;
 	fs_info->fs_devices = fs_devices;
 
 	fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
@@ -929,43 +961,30 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 	}
 
 	bdev = fs_devices->latest_bdev;
-	s = sget(fs_type, btrfs_test_super, btrfs_set_super,
-		 fs_info->tree_root);
+	s = sget(fs_type, btrfs_test_super, btrfs_set_super, fs_info);
 	if (IS_ERR(s)) {
 		error = PTR_ERR(s);
 		goto error_close_devices;
 	}
 
 	if (s->s_root) {
-		if ((flags ^ s->s_flags) & MS_RDONLY) {
-			deactivate_locked_super(s);
-			error = -EBUSY;
-			goto error_close_devices;
-		}
-
 		btrfs_close_devices(fs_devices);
 		free_fs_info(fs_info);
+		if ((flags ^ s->s_flags) & MS_RDONLY)
+			error = -EBUSY;
 	} else {
 		char b[BDEVNAME_SIZE];
 
 		s->s_flags = flags | MS_NOSEC;
 		strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
-		btrfs_sb(s)->fs_info->bdev_holder = fs_type;
+		btrfs_sb(s)->bdev_holder = fs_type;
 		error = btrfs_fill_super(s, fs_devices, data,
 					 flags & MS_SILENT ? 1 : 0);
-		if (error) {
-			deactivate_locked_super(s);
-			return ERR_PTR(error);
-		}
-
-		s->s_flags |= MS_ACTIVE;
 	}
 
-	root = get_default_root(s, subvol_objectid);
-	if (IS_ERR(root)) {
+	root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
+	if (IS_ERR(root))
 		deactivate_locked_super(s);
-		return root;
-	}
 
 	return root;
 
@@ -978,7 +997,8 @@ error_fs_info:
 
 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 {
-	struct btrfs_root *root = btrfs_sb(sb);
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	struct btrfs_root *root = fs_info->tree_root;
 	int ret;
 
 	ret = btrfs_parse_options(root, data);
@@ -994,13 +1014,13 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 		ret =  btrfs_commit_super(root);
 		WARN_ON(ret);
 	} else {
-		if (root->fs_info->fs_devices->rw_devices == 0)
+		if (fs_info->fs_devices->rw_devices == 0)
 			return -EACCES;
 
-		if (btrfs_super_log_root(root->fs_info->super_copy) != 0)
+		if (btrfs_super_log_root(fs_info->super_copy) != 0)
 			return -EINVAL;
 
-		ret = btrfs_cleanup_fs_roots(root->fs_info);
+		ret = btrfs_cleanup_fs_roots(fs_info);
 		WARN_ON(ret);
 
 		/* recover relocation */
@@ -1169,18 +1189,18 @@ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
 
 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
-	struct btrfs_root *root = btrfs_sb(dentry->d_sb);
-	struct btrfs_super_block *disk_super = root->fs_info->super_copy;
-	struct list_head *head = &root->fs_info->space_info;
+	struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
+	struct btrfs_super_block *disk_super = fs_info->super_copy;
+	struct list_head *head = &fs_info->space_info;
 	struct btrfs_space_info *found;
 	u64 total_used = 0;
 	u64 total_free_data = 0;
 	int bits = dentry->d_sb->s_blocksize_bits;
-	__be32 *fsid = (__be32 *)root->fs_info->fsid;
+	__be32 *fsid = (__be32 *)fs_info->fsid;
 	int ret;
 
 	/* holding chunk_muext to avoid allocating new chunks */
-	mutex_lock(&root->fs_info->chunk_mutex);
+	mutex_lock(&fs_info->chunk_mutex);
 	rcu_read_lock();
 	list_for_each_entry_rcu(found, head, list) {
 		if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
@@ -1199,14 +1219,14 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_bsize = dentry->d_sb->s_blocksize;
 	buf->f_type = BTRFS_SUPER_MAGIC;
 	buf->f_bavail = total_free_data;
-	ret = btrfs_calc_avail_data_space(root, &total_free_data);
+	ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
 	if (ret) {
-		mutex_unlock(&root->fs_info->chunk_mutex);
+		mutex_unlock(&fs_info->chunk_mutex);
 		return ret;
 	}
 	buf->f_bavail += total_free_data;
 	buf->f_bavail = buf->f_bavail >> bits;
-	mutex_unlock(&root->fs_info->chunk_mutex);
+	mutex_unlock(&fs_info->chunk_mutex);
 
 	/* We treat it as constant endianness (it doesn't matter _which_)
 	   because we want the fsid to come out the same whether mounted
@@ -1220,11 +1240,18 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	return 0;
 }
 
+static void btrfs_kill_super(struct super_block *sb)
+{
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	kill_anon_super(sb);
+	free_fs_info(fs_info);
+}
+
 static struct file_system_type btrfs_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "btrfs",
 	.mount		= btrfs_mount,
-	.kill_sb	= kill_anon_super,
+	.kill_sb	= btrfs_kill_super,
 	.fs_flags	= FS_REQUIRES_DEV,
 };
 
@@ -1258,17 +1285,17 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
 
 static int btrfs_freeze(struct super_block *sb)
 {
-	struct btrfs_root *root = btrfs_sb(sb);
-	mutex_lock(&root->fs_info->transaction_kthread_mutex);
-	mutex_lock(&root->fs_info->cleaner_mutex);
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	mutex_lock(&fs_info->transaction_kthread_mutex);
+	mutex_lock(&fs_info->cleaner_mutex);
 	return 0;
 }
 
 static int btrfs_unfreeze(struct super_block *sb)
 {
-	struct btrfs_root *root = btrfs_sb(sb);
-	mutex_unlock(&root->fs_info->cleaner_mutex);
-	mutex_unlock(&root->fs_info->transaction_kthread_mutex);
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	mutex_unlock(&fs_info->cleaner_mutex);
+	mutex_unlock(&fs_info->transaction_kthread_mutex);
 	return 0;
 }
 
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 81376d94cd3..287a6728b1a 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -36,6 +36,8 @@ static noinline void put_transaction(struct btrfs_transaction *transaction)
 	WARN_ON(atomic_read(&transaction->use_count) == 0);
 	if (atomic_dec_and_test(&transaction->use_count)) {
 		BUG_ON(!list_empty(&transaction->list));
+		WARN_ON(transaction->delayed_refs.root.rb_node);
+		WARN_ON(!list_empty(&transaction->delayed_refs.seq_head));
 		memset(transaction, 0, sizeof(*transaction));
 		kmem_cache_free(btrfs_transaction_cachep, transaction);
 	}
@@ -108,8 +110,11 @@ loop:
 	cur_trans->delayed_refs.num_heads = 0;
 	cur_trans->delayed_refs.flushing = 0;
 	cur_trans->delayed_refs.run_delayed_start = 0;
+	cur_trans->delayed_refs.seq = 1;
+	init_waitqueue_head(&cur_trans->delayed_refs.seq_wait);
 	spin_lock_init(&cur_trans->commit_lock);
 	spin_lock_init(&cur_trans->delayed_refs.lock);
+	INIT_LIST_HEAD(&cur_trans->delayed_refs.seq_head);
 
 	INIT_LIST_HEAD(&cur_trans->pending_snapshots);
 	list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
@@ -321,6 +326,8 @@ again:
 	}
 
 	if (num_bytes) {
+		trace_btrfs_space_reservation(root->fs_info, "transaction",
+					      (u64)h, num_bytes, 1);
 		h->block_rsv = &root->fs_info->trans_block_rsv;
 		h->bytes_reserved = num_bytes;
 	}
@@ -467,19 +474,12 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 
 	btrfs_trans_release_metadata(trans, root);
 	trans->block_rsv = NULL;
-	while (count < 4) {
+	while (count < 2) {
 		unsigned long cur = trans->delayed_ref_updates;
 		trans->delayed_ref_updates = 0;
 		if (cur &&
 		    trans->transaction->delayed_refs.num_heads_ready > 64) {
 			trans->delayed_ref_updates = 0;
-
-			/*
-			 * do a full flush if the transaction is trying
-			 * to close
-			 */
-			if (trans->transaction->delayed_refs.flushing)
-				cur = 0;
 			btrfs_run_delayed_refs(trans, root, cur);
 		} else {
 			break;
@@ -1393,9 +1393,9 @@ int btrfs_clean_old_snapshots(struct btrfs_root *root)
 
 		if (btrfs_header_backref_rev(root->node) <
 		    BTRFS_MIXED_BACKREF_REV)
-			btrfs_drop_snapshot(root, NULL, 0);
+			btrfs_drop_snapshot(root, NULL, 0, 0);
 		else
-			btrfs_drop_snapshot(root, NULL, 1);
+			btrfs_drop_snapshot(root, NULL, 1, 0);
 	}
 	return 0;
 }
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 3568374d419..966cc74f5d6 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -589,7 +589,7 @@ static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 				ret = btrfs_inc_extent_ref(trans, root,
 						ins.objectid, ins.offset,
 						0, root->root_key.objectid,
-						key->objectid, offset);
+						key->objectid, offset, 0);
 				BUG_ON(ret);
 			} else {
 				/*
@@ -1957,7 +1957,8 @@ static int wait_log_commit(struct btrfs_trans_handle *trans,
 
 		finish_wait(&root->log_commit_wait[index], &wait);
 		mutex_lock(&root->log_mutex);
-	} while (root->log_transid < transid + 2 &&
+	} while (root->fs_info->last_trans_log_full_commit !=
+		 trans->transid && root->log_transid < transid + 2 &&
 		 atomic_read(&root->log_commit[index]));
 	return 0;
 }
@@ -1966,7 +1967,8 @@ static int wait_for_writer(struct btrfs_trans_handle *trans,
 			   struct btrfs_root *root)
 {
 	DEFINE_WAIT(wait);
-	while (atomic_read(&root->log_writers)) {
+	while (root->fs_info->last_trans_log_full_commit !=
+	       trans->transid && atomic_read(&root->log_writers)) {
 		prepare_to_wait(&root->log_writer_wait,
 				&wait, TASK_UNINTERRUPTIBLE);
 		mutex_unlock(&root->log_mutex);
diff --git a/fs/btrfs/ulist.c b/fs/btrfs/ulist.c
new file mode 100644
index 00000000000..12f5147bd2b
--- /dev/null
+++ b/fs/btrfs/ulist.c
@@ -0,0 +1,220 @@
+/*
+ * Copyright (C) 2011 STRATO AG
+ * written by Arne Jansen <sensille@gmx.net>
+ * Distributed under the GNU GPL license version 2.
+ */
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include "ulist.h"
+
+/*
+ * ulist is a generic data structure to hold a collection of unique u64
+ * values. The only operations it supports is adding to the list and
+ * enumerating it.
+ * It is possible to store an auxiliary value along with the key.
+ *
+ * The implementation is preliminary and can probably be sped up
+ * significantly. A first step would be to store the values in an rbtree
+ * as soon as ULIST_SIZE is exceeded.
+ *
+ * A sample usage for ulists is the enumeration of directed graphs without
+ * visiting a node twice. The pseudo-code could look like this:
+ *
+ * ulist = ulist_alloc();
+ * ulist_add(ulist, root);
+ * elem = NULL;
+ *
+ * while ((elem = ulist_next(ulist, elem)) {
+ * 	for (all child nodes n in elem)
+ *		ulist_add(ulist, n);
+ *	do something useful with the node;
+ * }
+ * ulist_free(ulist);
+ *
+ * This assumes the graph nodes are adressable by u64. This stems from the
+ * usage for tree enumeration in btrfs, where the logical addresses are
+ * 64 bit.
+ *
+ * It is also useful for tree enumeration which could be done elegantly
+ * recursively, but is not possible due to kernel stack limitations. The
+ * loop would be similar to the above.
+ */
+
+/**
+ * ulist_init - freshly initialize a ulist
+ * @ulist:	the ulist to initialize
+ *
+ * Note: don't use this function to init an already used ulist, use
+ * ulist_reinit instead.
+ */
+void ulist_init(struct ulist *ulist)
+{
+	ulist->nnodes = 0;
+	ulist->nodes = ulist->int_nodes;
+	ulist->nodes_alloced = ULIST_SIZE;
+}
+EXPORT_SYMBOL(ulist_init);
+
+/**
+ * ulist_fini - free up additionally allocated memory for the ulist
+ * @ulist:	the ulist from which to free the additional memory
+ *
+ * This is useful in cases where the base 'struct ulist' has been statically
+ * allocated.
+ */
+void ulist_fini(struct ulist *ulist)
+{
+	/*
+	 * The first ULIST_SIZE elements are stored inline in struct ulist.
+	 * Only if more elements are alocated they need to be freed.
+	 */
+	if (ulist->nodes_alloced > ULIST_SIZE)
+		kfree(ulist->nodes);
+	ulist->nodes_alloced = 0;	/* in case ulist_fini is called twice */
+}
+EXPORT_SYMBOL(ulist_fini);
+
+/**
+ * ulist_reinit - prepare a ulist for reuse
+ * @ulist:	ulist to be reused
+ *
+ * Free up all additional memory allocated for the list elements and reinit
+ * the ulist.
+ */
+void ulist_reinit(struct ulist *ulist)
+{
+	ulist_fini(ulist);
+	ulist_init(ulist);
+}
+EXPORT_SYMBOL(ulist_reinit);
+
+/**
+ * ulist_alloc - dynamically allocate a ulist
+ * @gfp_mask:	allocation flags to for base allocation
+ *
+ * The allocated ulist will be returned in an initialized state.
+ */
+struct ulist *ulist_alloc(unsigned long gfp_mask)
+{
+	struct ulist *ulist = kmalloc(sizeof(*ulist), gfp_mask);
+
+	if (!ulist)
+		return NULL;
+
+	ulist_init(ulist);
+
+	return ulist;
+}
+EXPORT_SYMBOL(ulist_alloc);
+
+/**
+ * ulist_free - free dynamically allocated ulist
+ * @ulist:	ulist to free
+ *
+ * It is not necessary to call ulist_fini before.
+ */
+void ulist_free(struct ulist *ulist)
+{
+	if (!ulist)
+		return;
+	ulist_fini(ulist);
+	kfree(ulist);
+}
+EXPORT_SYMBOL(ulist_free);
+
+/**
+ * ulist_add - add an element to the ulist
+ * @ulist:	ulist to add the element to
+ * @val:	value to add to ulist
+ * @aux:	auxiliary value to store along with val
+ * @gfp_mask:	flags to use for allocation
+ *
+ * Note: locking must be provided by the caller. In case of rwlocks write
+ *       locking is needed
+ *
+ * Add an element to a ulist. The @val will only be added if it doesn't
+ * already exist. If it is added, the auxiliary value @aux is stored along with
+ * it. In case @val already exists in the ulist, @aux is ignored, even if
+ * it differs from the already stored value.
+ *
+ * ulist_add returns 0 if @val already exists in ulist and 1 if @val has been
+ * inserted.
+ * In case of allocation failure -ENOMEM is returned and the ulist stays
+ * unaltered.
+ */
+int ulist_add(struct ulist *ulist, u64 val, unsigned long aux,
+	      unsigned long gfp_mask)
+{
+	int i;
+
+	for (i = 0; i < ulist->nnodes; ++i) {
+		if (ulist->nodes[i].val == val)
+			return 0;
+	}
+
+	if (ulist->nnodes >= ulist->nodes_alloced) {
+		u64 new_alloced = ulist->nodes_alloced + 128;
+		struct ulist_node *new_nodes;
+		void *old = NULL;
+
+		/*
+		 * if nodes_alloced == ULIST_SIZE no memory has been allocated
+		 * yet, so pass NULL to krealloc
+		 */
+		if (ulist->nodes_alloced > ULIST_SIZE)
+			old = ulist->nodes;
+
+		new_nodes = krealloc(old, sizeof(*new_nodes) * new_alloced,
+				     gfp_mask);
+		if (!new_nodes)
+			return -ENOMEM;
+
+		if (!old)
+			memcpy(new_nodes, ulist->int_nodes,
+			       sizeof(ulist->int_nodes));
+
+		ulist->nodes = new_nodes;
+		ulist->nodes_alloced = new_alloced;
+	}
+	ulist->nodes[ulist->nnodes].val = val;
+	ulist->nodes[ulist->nnodes].aux = aux;
+	++ulist->nnodes;
+
+	return 1;
+}
+EXPORT_SYMBOL(ulist_add);
+
+/**
+ * ulist_next - iterate ulist
+ * @ulist:	ulist to iterate
+ * @prev:	previously returned element or %NULL to start iteration
+ *
+ * Note: locking must be provided by the caller. In case of rwlocks only read
+ *       locking is needed
+ *
+ * This function is used to iterate an ulist. The iteration is started with
+ * @prev = %NULL. It returns the next element from the ulist or %NULL when the
+ * end is reached. No guarantee is made with respect to the order in which
+ * the elements are returned. They might neither be returned in order of
+ * addition nor in ascending order.
+ * It is allowed to call ulist_add during an enumeration. Newly added items
+ * are guaranteed to show up in the running enumeration.
+ */
+struct ulist_node *ulist_next(struct ulist *ulist, struct ulist_node *prev)
+{
+	int next;
+
+	if (ulist->nnodes == 0)
+		return NULL;
+
+	if (!prev)
+		return &ulist->nodes[0];
+
+	next = (prev - ulist->nodes) + 1;
+	if (next < 0 || next >= ulist->nnodes)
+		return NULL;
+
+	return &ulist->nodes[next];
+}
+EXPORT_SYMBOL(ulist_next);
diff --git a/fs/btrfs/ulist.h b/fs/btrfs/ulist.h
new file mode 100644
index 00000000000..2e25dec58ec
--- /dev/null
+++ b/fs/btrfs/ulist.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2011 STRATO AG
+ * written by Arne Jansen <sensille@gmx.net>
+ * Distributed under the GNU GPL license version 2.
+ *
+ */
+
+#ifndef __ULIST__
+#define __ULIST__
+
+/*
+ * ulist is a generic data structure to hold a collection of unique u64
+ * values. The only operations it supports is adding to the list and
+ * enumerating it.
+ * It is possible to store an auxiliary value along with the key.
+ *
+ * The implementation is preliminary and can probably be sped up
+ * significantly. A first step would be to store the values in an rbtree
+ * as soon as ULIST_SIZE is exceeded.
+ */
+
+/*
+ * number of elements statically allocated inside struct ulist
+ */
+#define ULIST_SIZE 16
+
+/*
+ * element of the list
+ */
+struct ulist_node {
+	u64 val;		/* value to store */
+	unsigned long aux;	/* auxiliary value saved along with the val */
+};
+
+struct ulist {
+	/*
+	 * number of elements stored in list
+	 */
+	unsigned long nnodes;
+
+	/*
+	 * number of nodes we already have room for
+	 */
+	unsigned long nodes_alloced;
+
+	/*
+	 * pointer to the array storing the elements. The first ULIST_SIZE
+	 * elements are stored inline. In this case the it points to int_nodes.
+	 * After exceeding ULIST_SIZE, dynamic memory is allocated.
+	 */
+	struct ulist_node *nodes;
+
+	/*
+	 * inline storage space for the first ULIST_SIZE entries
+	 */
+	struct ulist_node int_nodes[ULIST_SIZE];
+};
+
+void ulist_init(struct ulist *ulist);
+void ulist_fini(struct ulist *ulist);
+void ulist_reinit(struct ulist *ulist);
+struct ulist *ulist_alloc(unsigned long gfp_mask);
+void ulist_free(struct ulist *ulist);
+int ulist_add(struct ulist *ulist, u64 val, unsigned long aux,
+	      unsigned long gfp_mask);
+struct ulist_node *ulist_next(struct ulist *ulist, struct ulist_node *prev);
+
+#endif
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index f4b839fd3c9..0b4e2af7954 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -23,6 +23,7 @@
 #include <linux/random.h>
 #include <linux/iocontext.h>
 #include <linux/capability.h>
+#include <linux/kthread.h>
 #include <asm/div64.h>
 #include "compat.h"
 #include "ctree.h"
@@ -32,6 +33,7 @@
 #include "print-tree.h"
 #include "volumes.h"
 #include "async-thread.h"
+#include "check-integrity.h"
 
 static int init_first_rw_device(struct btrfs_trans_handle *trans,
 				struct btrfs_root *root,
@@ -246,7 +248,7 @@ loop_lock:
 			sync_pending = 0;
 		}
 
-		submit_bio(cur->bi_rw, cur);
+		btrfsic_submit_bio(cur->bi_rw, cur);
 		num_run++;
 		batch_run++;
 		if (need_resched())
@@ -706,8 +708,6 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 	u64 devid;
 	u64 transid;
 
-	mutex_lock(&uuid_mutex);
-
 	flags |= FMODE_EXCL;
 	bdev = blkdev_get_by_path(path, flags, holder);
 
@@ -716,6 +716,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 		goto error;
 	}
 
+	mutex_lock(&uuid_mutex);
 	ret = set_blocksize(bdev, 4096);
 	if (ret)
 		goto error_close;
@@ -737,9 +738,9 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 
 	brelse(bh);
 error_close:
+	mutex_unlock(&uuid_mutex);
 	blkdev_put(bdev, flags);
 error:
-	mutex_unlock(&uuid_mutex);
 	return ret;
 }
 
@@ -829,7 +830,6 @@ out:
 
 /*
  * find_free_dev_extent - find free space in the specified device
- * @trans:	transaction handler
  * @device:	the device which we search the free space in
  * @num_bytes:	the size of the free space that we need
  * @start:	store the start of the free space.
@@ -848,8 +848,7 @@ out:
  * But if we don't find suitable free space, it is used to store the size of
  * the max free space.
  */
-int find_free_dev_extent(struct btrfs_trans_handle *trans,
-			 struct btrfs_device *device, u64 num_bytes,
+int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 			 u64 *start, u64 *len)
 {
 	struct btrfs_key key;
@@ -893,7 +892,7 @@ int find_free_dev_extent(struct btrfs_trans_handle *trans,
 	key.offset = search_start;
 	key.type = BTRFS_DEV_EXTENT_KEY;
 
-	ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
+	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 	if (ret < 0)
 		goto out;
 	if (ret > 0) {
@@ -1282,7 +1281,6 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 	bool clear_super = false;
 
 	mutex_lock(&uuid_mutex);
-	mutex_lock(&root->fs_info->volume_mutex);
 
 	all_avail = root->fs_info->avail_data_alloc_bits |
 		root->fs_info->avail_system_alloc_bits |
@@ -1452,7 +1450,6 @@ error_close:
 	if (bdev)
 		blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
 out:
-	mutex_unlock(&root->fs_info->volume_mutex);
 	mutex_unlock(&uuid_mutex);
 	return ret;
 error_undo:
@@ -1469,8 +1466,7 @@ error_undo:
 /*
  * does all the dirty work required for changing file system's UUID.
  */
-static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
-				struct btrfs_root *root)
+static int btrfs_prepare_sprout(struct btrfs_root *root)
 {
 	struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
 	struct btrfs_fs_devices *old_devices;
@@ -1629,7 +1625,6 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 	}
 
 	filemap_write_and_wait(bdev->bd_inode->i_mapping);
-	mutex_lock(&root->fs_info->volume_mutex);
 
 	devices = &root->fs_info->fs_devices->devices;
 	/*
@@ -1695,7 +1690,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 
 	if (seeding_dev) {
 		sb->s_flags &= ~MS_RDONLY;
-		ret = btrfs_prepare_sprout(trans, root);
+		ret = btrfs_prepare_sprout(root);
 		BUG_ON(ret);
 	}
 
@@ -1757,8 +1752,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 		ret = btrfs_relocate_sys_chunks(root);
 		BUG_ON(ret);
 	}
-out:
-	mutex_unlock(&root->fs_info->volume_mutex);
+
 	return ret;
 error:
 	blkdev_put(bdev, FMODE_EXCL);
@@ -1766,7 +1760,7 @@ error:
 		mutex_unlock(&uuid_mutex);
 		up_write(&sb->s_umount);
 	}
-	goto out;
+	return ret;
 }
 
 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
@@ -2077,6 +2071,362 @@ error:
 	return ret;
 }
 
+static int insert_balance_item(struct btrfs_root *root,
+			       struct btrfs_balance_control *bctl)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_balance_item *item;
+	struct btrfs_disk_balance_args disk_bargs;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct btrfs_key key;
+	int ret, err;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	trans = btrfs_start_transaction(root, 0);
+	if (IS_ERR(trans)) {
+		btrfs_free_path(path);
+		return PTR_ERR(trans);
+	}
+
+	key.objectid = BTRFS_BALANCE_OBJECTID;
+	key.type = BTRFS_BALANCE_ITEM_KEY;
+	key.offset = 0;
+
+	ret = btrfs_insert_empty_item(trans, root, path, &key,
+				      sizeof(*item));
+	if (ret)
+		goto out;
+
+	leaf = path->nodes[0];
+	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
+
+	memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
+
+	btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
+	btrfs_set_balance_data(leaf, item, &disk_bargs);
+	btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
+	btrfs_set_balance_meta(leaf, item, &disk_bargs);
+	btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
+	btrfs_set_balance_sys(leaf, item, &disk_bargs);
+
+	btrfs_set_balance_flags(leaf, item, bctl->flags);
+
+	btrfs_mark_buffer_dirty(leaf);
+out:
+	btrfs_free_path(path);
+	err = btrfs_commit_transaction(trans, root);
+	if (err && !ret)
+		ret = err;
+	return ret;
+}
+
+static int del_balance_item(struct btrfs_root *root)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	int ret, err;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	trans = btrfs_start_transaction(root, 0);
+	if (IS_ERR(trans)) {
+		btrfs_free_path(path);
+		return PTR_ERR(trans);
+	}
+
+	key.objectid = BTRFS_BALANCE_OBJECTID;
+	key.type = BTRFS_BALANCE_ITEM_KEY;
+	key.offset = 0;
+
+	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+	if (ret < 0)
+		goto out;
+	if (ret > 0) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	ret = btrfs_del_item(trans, root, path);
+out:
+	btrfs_free_path(path);
+	err = btrfs_commit_transaction(trans, root);
+	if (err && !ret)
+		ret = err;
+	return ret;
+}
+
+/*
+ * This is a heuristic used to reduce the number of chunks balanced on
+ * resume after balance was interrupted.
+ */
+static void update_balance_args(struct btrfs_balance_control *bctl)
+{
+	/*
+	 * Turn on soft mode for chunk types that were being converted.
+	 */
+	if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
+		bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
+	if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
+		bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
+	if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
+		bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
+
+	/*
+	 * Turn on usage filter if is not already used.  The idea is
+	 * that chunks that we have already balanced should be
+	 * reasonably full.  Don't do it for chunks that are being
+	 * converted - that will keep us from relocating unconverted
+	 * (albeit full) chunks.
+	 */
+	if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
+	    !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
+		bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
+		bctl->data.usage = 90;
+	}
+	if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
+	    !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
+		bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
+		bctl->sys.usage = 90;
+	}
+	if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
+	    !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
+		bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
+		bctl->meta.usage = 90;
+	}
+}
+
+/*
+ * Should be called with both balance and volume mutexes held to
+ * serialize other volume operations (add_dev/rm_dev/resize) with
+ * restriper.  Same goes for unset_balance_control.
+ */
+static void set_balance_control(struct btrfs_balance_control *bctl)
+{
+	struct btrfs_fs_info *fs_info = bctl->fs_info;
+
+	BUG_ON(fs_info->balance_ctl);
+
+	spin_lock(&fs_info->balance_lock);
+	fs_info->balance_ctl = bctl;
+	spin_unlock(&fs_info->balance_lock);
+}
+
+static void unset_balance_control(struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
+
+	BUG_ON(!fs_info->balance_ctl);
+
+	spin_lock(&fs_info->balance_lock);
+	fs_info->balance_ctl = NULL;
+	spin_unlock(&fs_info->balance_lock);
+
+	kfree(bctl);
+}
+
+/*
+ * Balance filters.  Return 1 if chunk should be filtered out
+ * (should not be balanced).
+ */
+static int chunk_profiles_filter(u64 chunk_profile,
+				 struct btrfs_balance_args *bargs)
+{
+	chunk_profile &= BTRFS_BLOCK_GROUP_PROFILE_MASK;
+
+	if (chunk_profile == 0)
+		chunk_profile = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+
+	if (bargs->profiles & chunk_profile)
+		return 0;
+
+	return 1;
+}
+
+static u64 div_factor_fine(u64 num, int factor)
+{
+	if (factor <= 0)
+		return 0;
+	if (factor >= 100)
+		return num;
+
+	num *= factor;
+	do_div(num, 100);
+	return num;
+}
+
+static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
+			      struct btrfs_balance_args *bargs)
+{
+	struct btrfs_block_group_cache *cache;
+	u64 chunk_used, user_thresh;
+	int ret = 1;
+
+	cache = btrfs_lookup_block_group(fs_info, chunk_offset);
+	chunk_used = btrfs_block_group_used(&cache->item);
+
+	user_thresh = div_factor_fine(cache->key.offset, bargs->usage);
+	if (chunk_used < user_thresh)
+		ret = 0;
+
+	btrfs_put_block_group(cache);
+	return ret;
+}
+
+static int chunk_devid_filter(struct extent_buffer *leaf,
+			      struct btrfs_chunk *chunk,
+			      struct btrfs_balance_args *bargs)
+{
+	struct btrfs_stripe *stripe;
+	int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
+	int i;
+
+	for (i = 0; i < num_stripes; i++) {
+		stripe = btrfs_stripe_nr(chunk, i);
+		if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
+			return 0;
+	}
+
+	return 1;
+}
+
+/* [pstart, pend) */
+static int chunk_drange_filter(struct extent_buffer *leaf,
+			       struct btrfs_chunk *chunk,
+			       u64 chunk_offset,
+			       struct btrfs_balance_args *bargs)
+{
+	struct btrfs_stripe *stripe;
+	int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
+	u64 stripe_offset;
+	u64 stripe_length;
+	int factor;
+	int i;
+
+	if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
+		return 0;
+
+	if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
+	     BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10))
+		factor = 2;
+	else
+		factor = 1;
+	factor = num_stripes / factor;
+
+	for (i = 0; i < num_stripes; i++) {
+		stripe = btrfs_stripe_nr(chunk, i);
+		if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
+			continue;
+
+		stripe_offset = btrfs_stripe_offset(leaf, stripe);
+		stripe_length = btrfs_chunk_length(leaf, chunk);
+		do_div(stripe_length, factor);
+
+		if (stripe_offset < bargs->pend &&
+		    stripe_offset + stripe_length > bargs->pstart)
+			return 0;
+	}
+
+	return 1;
+}
+
+/* [vstart, vend) */
+static int chunk_vrange_filter(struct extent_buffer *leaf,
+			       struct btrfs_chunk *chunk,
+			       u64 chunk_offset,
+			       struct btrfs_balance_args *bargs)
+{
+	if (chunk_offset < bargs->vend &&
+	    chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
+		/* at least part of the chunk is inside this vrange */
+		return 0;
+
+	return 1;
+}
+
+static int chunk_soft_convert_filter(u64 chunk_profile,
+				     struct btrfs_balance_args *bargs)
+{
+	if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
+		return 0;
+
+	chunk_profile &= BTRFS_BLOCK_GROUP_PROFILE_MASK;
+
+	if (chunk_profile == 0)
+		chunk_profile = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+
+	if (bargs->target & chunk_profile)
+		return 1;
+
+	return 0;
+}
+
+static int should_balance_chunk(struct btrfs_root *root,
+				struct extent_buffer *leaf,
+				struct btrfs_chunk *chunk, u64 chunk_offset)
+{
+	struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
+	struct btrfs_balance_args *bargs = NULL;
+	u64 chunk_type = btrfs_chunk_type(leaf, chunk);
+
+	/* type filter */
+	if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
+	      (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
+		return 0;
+	}
+
+	if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
+		bargs = &bctl->data;
+	else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
+		bargs = &bctl->sys;
+	else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
+		bargs = &bctl->meta;
+
+	/* profiles filter */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
+	    chunk_profiles_filter(chunk_type, bargs)) {
+		return 0;
+	}
+
+	/* usage filter */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
+	    chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
+		return 0;
+	}
+
+	/* devid filter */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
+	    chunk_devid_filter(leaf, chunk, bargs)) {
+		return 0;
+	}
+
+	/* drange filter, makes sense only with devid filter */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
+	    chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
+		return 0;
+	}
+
+	/* vrange filter */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
+	    chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
+		return 0;
+	}
+
+	/* soft profile changing mode */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
+	    chunk_soft_convert_filter(chunk_type, bargs)) {
+		return 0;
+	}
+
+	return 1;
+}
+
 static u64 div_factor(u64 num, int factor)
 {
 	if (factor == 10)
@@ -2086,29 +2436,28 @@ static u64 div_factor(u64 num, int factor)
 	return num;
 }
 
-int btrfs_balance(struct btrfs_root *dev_root)
+static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 {
-	int ret;
-	struct list_head *devices = &dev_root->fs_info->fs_devices->devices;
+	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
+	struct btrfs_root *chunk_root = fs_info->chunk_root;
+	struct btrfs_root *dev_root = fs_info->dev_root;
+	struct list_head *devices;
 	struct btrfs_device *device;
 	u64 old_size;
 	u64 size_to_free;
+	struct btrfs_chunk *chunk;
 	struct btrfs_path *path;
 	struct btrfs_key key;
-	struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
-	struct btrfs_trans_handle *trans;
 	struct btrfs_key found_key;
-
-	if (dev_root->fs_info->sb->s_flags & MS_RDONLY)
-		return -EROFS;
-
-	if (!capable(CAP_SYS_ADMIN))
-		return -EPERM;
-
-	mutex_lock(&dev_root->fs_info->volume_mutex);
-	dev_root = dev_root->fs_info->dev_root;
+	struct btrfs_trans_handle *trans;
+	struct extent_buffer *leaf;
+	int slot;
+	int ret;
+	int enospc_errors = 0;
+	bool counting = true;
 
 	/* step one make some room on all the devices */
+	devices = &fs_info->fs_devices->devices;
 	list_for_each_entry(device, devices, dev_list) {
 		old_size = device->total_bytes;
 		size_to_free = div_factor(old_size, 1);
@@ -2137,11 +2486,23 @@ int btrfs_balance(struct btrfs_root *dev_root)
 		ret = -ENOMEM;
 		goto error;
 	}
+
+	/* zero out stat counters */
+	spin_lock(&fs_info->balance_lock);
+	memset(&bctl->stat, 0, sizeof(bctl->stat));
+	spin_unlock(&fs_info->balance_lock);
+again:
 	key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
 	key.offset = (u64)-1;
 	key.type = BTRFS_CHUNK_ITEM_KEY;
 
 	while (1) {
+		if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
+		    atomic_read(&fs_info->balance_cancel_req)) {
+			ret = -ECANCELED;
+			goto error;
+		}
+
 		ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
 		if (ret < 0)
 			goto error;
@@ -2151,15 +2512,19 @@ int btrfs_balance(struct btrfs_root *dev_root)
 		 * failed
 		 */
 		if (ret == 0)
-			break;
+			BUG(); /* FIXME break ? */
 
 		ret = btrfs_previous_item(chunk_root, path, 0,
 					  BTRFS_CHUNK_ITEM_KEY);
-		if (ret)
+		if (ret) {
+			ret = 0;
 			break;
+		}
+
+		leaf = path->nodes[0];
+		slot = path->slots[0];
+		btrfs_item_key_to_cpu(leaf, &found_key, slot);
 
-		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
-				      path->slots[0]);
 		if (found_key.objectid != key.objectid)
 			break;
 
@@ -2167,22 +2532,375 @@ int btrfs_balance(struct btrfs_root *dev_root)
 		if (found_key.offset == 0)
 			break;
 
+		chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
+
+		if (!counting) {
+			spin_lock(&fs_info->balance_lock);
+			bctl->stat.considered++;
+			spin_unlock(&fs_info->balance_lock);
+		}
+
+		ret = should_balance_chunk(chunk_root, leaf, chunk,
+					   found_key.offset);
 		btrfs_release_path(path);
+		if (!ret)
+			goto loop;
+
+		if (counting) {
+			spin_lock(&fs_info->balance_lock);
+			bctl->stat.expected++;
+			spin_unlock(&fs_info->balance_lock);
+			goto loop;
+		}
+
 		ret = btrfs_relocate_chunk(chunk_root,
 					   chunk_root->root_key.objectid,
 					   found_key.objectid,
 					   found_key.offset);
 		if (ret && ret != -ENOSPC)
 			goto error;
+		if (ret == -ENOSPC) {
+			enospc_errors++;
+		} else {
+			spin_lock(&fs_info->balance_lock);
+			bctl->stat.completed++;
+			spin_unlock(&fs_info->balance_lock);
+		}
+loop:
 		key.offset = found_key.offset - 1;
 	}
-	ret = 0;
+
+	if (counting) {
+		btrfs_release_path(path);
+		counting = false;
+		goto again;
+	}
 error:
 	btrfs_free_path(path);
-	mutex_unlock(&dev_root->fs_info->volume_mutex);
+	if (enospc_errors) {
+		printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
+		       enospc_errors);
+		if (!ret)
+			ret = -ENOSPC;
+	}
+
 	return ret;
 }
 
+static inline int balance_need_close(struct btrfs_fs_info *fs_info)
+{
+	/* cancel requested || normal exit path */
+	return atomic_read(&fs_info->balance_cancel_req) ||
+		(atomic_read(&fs_info->balance_pause_req) == 0 &&
+		 atomic_read(&fs_info->balance_cancel_req) == 0);
+}
+
+static void __cancel_balance(struct btrfs_fs_info *fs_info)
+{
+	int ret;
+
+	unset_balance_control(fs_info);
+	ret = del_balance_item(fs_info->tree_root);
+	BUG_ON(ret);
+}
+
+void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
+			       struct btrfs_ioctl_balance_args *bargs);
+
+/*
+ * Should be called with both balance and volume mutexes held
+ */
+int btrfs_balance(struct btrfs_balance_control *bctl,
+		  struct btrfs_ioctl_balance_args *bargs)
+{
+	struct btrfs_fs_info *fs_info = bctl->fs_info;
+	u64 allowed;
+	int ret;
+
+	if (btrfs_fs_closing(fs_info) ||
+	    atomic_read(&fs_info->balance_pause_req) ||
+	    atomic_read(&fs_info->balance_cancel_req)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * In case of mixed groups both data and meta should be picked,
+	 * and identical options should be given for both of them.
+	 */
+	allowed = btrfs_super_incompat_flags(fs_info->super_copy);
+	if ((allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) &&
+	    (bctl->flags & (BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA))) {
+		if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
+		    !(bctl->flags & BTRFS_BALANCE_METADATA) ||
+		    memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
+			printk(KERN_ERR "btrfs: with mixed groups data and "
+			       "metadata balance options must be the same\n");
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+	/*
+	 * Profile changing sanity checks.  Skip them if a simple
+	 * balance is requested.
+	 */
+	if (!((bctl->data.flags | bctl->sys.flags | bctl->meta.flags) &
+	      BTRFS_BALANCE_ARGS_CONVERT))
+		goto do_balance;
+
+	allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+	if (fs_info->fs_devices->num_devices == 1)
+		allowed |= BTRFS_BLOCK_GROUP_DUP;
+	else if (fs_info->fs_devices->num_devices < 4)
+		allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
+	else
+		allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
+				BTRFS_BLOCK_GROUP_RAID10);
+
+	if (!profile_is_valid(bctl->data.target, 1) ||
+	    bctl->data.target & ~allowed) {
+		printk(KERN_ERR "btrfs: unable to start balance with target "
+		       "data profile %llu\n",
+		       (unsigned long long)bctl->data.target);
+		ret = -EINVAL;
+		goto out;
+	}
+	if (!profile_is_valid(bctl->meta.target, 1) ||
+	    bctl->meta.target & ~allowed) {
+		printk(KERN_ERR "btrfs: unable to start balance with target "
+		       "metadata profile %llu\n",
+		       (unsigned long long)bctl->meta.target);
+		ret = -EINVAL;
+		goto out;
+	}
+	if (!profile_is_valid(bctl->sys.target, 1) ||
+	    bctl->sys.target & ~allowed) {
+		printk(KERN_ERR "btrfs: unable to start balance with target "
+		       "system profile %llu\n",
+		       (unsigned long long)bctl->sys.target);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (bctl->data.target & BTRFS_BLOCK_GROUP_DUP) {
+		printk(KERN_ERR "btrfs: dup for data is not allowed\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* allow to reduce meta or sys integrity only if force set */
+	allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
+			BTRFS_BLOCK_GROUP_RAID10;
+	if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
+	     (fs_info->avail_system_alloc_bits & allowed) &&
+	     !(bctl->sys.target & allowed)) ||
+	    ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
+	     (fs_info->avail_metadata_alloc_bits & allowed) &&
+	     !(bctl->meta.target & allowed))) {
+		if (bctl->flags & BTRFS_BALANCE_FORCE) {
+			printk(KERN_INFO "btrfs: force reducing metadata "
+			       "integrity\n");
+		} else {
+			printk(KERN_ERR "btrfs: balance will reduce metadata "
+			       "integrity, use force if you want this\n");
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+do_balance:
+	ret = insert_balance_item(fs_info->tree_root, bctl);
+	if (ret && ret != -EEXIST)
+		goto out;
+
+	if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
+		BUG_ON(ret == -EEXIST);
+		set_balance_control(bctl);
+	} else {
+		BUG_ON(ret != -EEXIST);
+		spin_lock(&fs_info->balance_lock);
+		update_balance_args(bctl);
+		spin_unlock(&fs_info->balance_lock);
+	}
+
+	atomic_inc(&fs_info->balance_running);
+	mutex_unlock(&fs_info->balance_mutex);
+
+	ret = __btrfs_balance(fs_info);
+
+	mutex_lock(&fs_info->balance_mutex);
+	atomic_dec(&fs_info->balance_running);
+
+	if (bargs) {
+		memset(bargs, 0, sizeof(*bargs));
+		update_ioctl_balance_args(fs_info, 0, bargs);
+	}
+
+	if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
+	    balance_need_close(fs_info)) {
+		__cancel_balance(fs_info);
+	}
+
+	wake_up(&fs_info->balance_wait_q);
+
+	return ret;
+out:
+	if (bctl->flags & BTRFS_BALANCE_RESUME)
+		__cancel_balance(fs_info);
+	else
+		kfree(bctl);
+	return ret;
+}
+
+static int balance_kthread(void *data)
+{
+	struct btrfs_balance_control *bctl =
+			(struct btrfs_balance_control *)data;
+	struct btrfs_fs_info *fs_info = bctl->fs_info;
+	int ret = 0;
+
+	mutex_lock(&fs_info->volume_mutex);
+	mutex_lock(&fs_info->balance_mutex);
+
+	set_balance_control(bctl);
+
+	if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
+		printk(KERN_INFO "btrfs: force skipping balance\n");
+	} else {
+		printk(KERN_INFO "btrfs: continuing balance\n");
+		ret = btrfs_balance(bctl, NULL);
+	}
+
+	mutex_unlock(&fs_info->balance_mutex);
+	mutex_unlock(&fs_info->volume_mutex);
+	return ret;
+}
+
+int btrfs_recover_balance(struct btrfs_root *tree_root)
+{
+	struct task_struct *tsk;
+	struct btrfs_balance_control *bctl;
+	struct btrfs_balance_item *item;
+	struct btrfs_disk_balance_args disk_bargs;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct btrfs_key key;
+	int ret;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
+	if (!bctl) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	key.objectid = BTRFS_BALANCE_OBJECTID;
+	key.type = BTRFS_BALANCE_ITEM_KEY;
+	key.offset = 0;
+
+	ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
+	if (ret < 0)
+		goto out_bctl;
+	if (ret > 0) { /* ret = -ENOENT; */
+		ret = 0;
+		goto out_bctl;
+	}
+
+	leaf = path->nodes[0];
+	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
+
+	bctl->fs_info = tree_root->fs_info;
+	bctl->flags = btrfs_balance_flags(leaf, item) | BTRFS_BALANCE_RESUME;
+
+	btrfs_balance_data(leaf, item, &disk_bargs);
+	btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
+	btrfs_balance_meta(leaf, item, &disk_bargs);
+	btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
+	btrfs_balance_sys(leaf, item, &disk_bargs);
+	btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
+
+	tsk = kthread_run(balance_kthread, bctl, "btrfs-balance");
+	if (IS_ERR(tsk))
+		ret = PTR_ERR(tsk);
+	else
+		goto out;
+
+out_bctl:
+	kfree(bctl);
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
+int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
+{
+	int ret = 0;
+
+	mutex_lock(&fs_info->balance_mutex);
+	if (!fs_info->balance_ctl) {
+		mutex_unlock(&fs_info->balance_mutex);
+		return -ENOTCONN;
+	}
+
+	if (atomic_read(&fs_info->balance_running)) {
+		atomic_inc(&fs_info->balance_pause_req);
+		mutex_unlock(&fs_info->balance_mutex);
+
+		wait_event(fs_info->balance_wait_q,
+			   atomic_read(&fs_info->balance_running) == 0);
+
+		mutex_lock(&fs_info->balance_mutex);
+		/* we are good with balance_ctl ripped off from under us */
+		BUG_ON(atomic_read(&fs_info->balance_running));
+		atomic_dec(&fs_info->balance_pause_req);
+	} else {
+		ret = -ENOTCONN;
+	}
+
+	mutex_unlock(&fs_info->balance_mutex);
+	return ret;
+}
+
+int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
+{
+	mutex_lock(&fs_info->balance_mutex);
+	if (!fs_info->balance_ctl) {
+		mutex_unlock(&fs_info->balance_mutex);
+		return -ENOTCONN;
+	}
+
+	atomic_inc(&fs_info->balance_cancel_req);
+	/*
+	 * if we are running just wait and return, balance item is
+	 * deleted in btrfs_balance in this case
+	 */
+	if (atomic_read(&fs_info->balance_running)) {
+		mutex_unlock(&fs_info->balance_mutex);
+		wait_event(fs_info->balance_wait_q,
+			   atomic_read(&fs_info->balance_running) == 0);
+		mutex_lock(&fs_info->balance_mutex);
+	} else {
+		/* __cancel_balance needs volume_mutex */
+		mutex_unlock(&fs_info->balance_mutex);
+		mutex_lock(&fs_info->volume_mutex);
+		mutex_lock(&fs_info->balance_mutex);
+
+		if (fs_info->balance_ctl)
+			__cancel_balance(fs_info);
+
+		mutex_unlock(&fs_info->volume_mutex);
+	}
+
+	BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
+	atomic_dec(&fs_info->balance_cancel_req);
+	mutex_unlock(&fs_info->balance_mutex);
+	return 0;
+}
+
 /*
  * shrinking a device means finding all of the device extents past
  * the new size, and then following the back refs to the chunks.
@@ -2323,8 +3041,7 @@ done:
 	return ret;
 }
 
-static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
-			   struct btrfs_root *root,
+static int btrfs_add_system_chunk(struct btrfs_root *root,
 			   struct btrfs_key *key,
 			   struct btrfs_chunk *chunk, int item_size)
 {
@@ -2441,10 +3158,14 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 		max_stripe_size = 1024 * 1024 * 1024;
 		max_chunk_size = 10 * max_stripe_size;
 	} else if (type & BTRFS_BLOCK_GROUP_METADATA) {
-		max_stripe_size = 256 * 1024 * 1024;
+		/* for larger filesystems, use larger metadata chunks */
+		if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
+			max_stripe_size = 1024 * 1024 * 1024;
+		else
+			max_stripe_size = 256 * 1024 * 1024;
 		max_chunk_size = max_stripe_size;
 	} else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
-		max_stripe_size = 8 * 1024 * 1024;
+		max_stripe_size = 32 * 1024 * 1024;
 		max_chunk_size = 2 * max_stripe_size;
 	} else {
 		printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
@@ -2496,7 +3217,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 		if (total_avail == 0)
 			continue;
 
-		ret = find_free_dev_extent(trans, device,
+		ret = find_free_dev_extent(device,
 					   max_stripe_size * dev_stripes,
 					   &dev_offset, &max_avail);
 		if (ret && ret != -ENOSPC)
@@ -2687,7 +3408,7 @@ static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
 	BUG_ON(ret);
 
 	if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
-		ret = btrfs_add_system_chunk(trans, chunk_root, &key, chunk,
+		ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
 					     item_size);
 		BUG_ON(ret);
 	}
@@ -2752,8 +3473,7 @@ static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
 		return ret;
 
 	alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
-			(fs_info->metadata_alloc_profile &
-			 fs_info->avail_metadata_alloc_bits);
+				fs_info->avail_metadata_alloc_bits;
 	alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
 
 	ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
@@ -2763,8 +3483,7 @@ static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
 	sys_chunk_offset = chunk_offset + chunk_size;
 
 	alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
-			(fs_info->system_alloc_profile &
-			 fs_info->avail_system_alloc_bits);
+				fs_info->avail_system_alloc_bits;
 	alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
 
 	ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
@@ -2901,26 +3620,13 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 	u64 stripe_nr;
 	u64 stripe_nr_orig;
 	u64 stripe_nr_end;
-	int stripes_allocated = 8;
-	int stripes_required = 1;
 	int stripe_index;
 	int i;
+	int ret = 0;
 	int num_stripes;
 	int max_errors = 0;
 	struct btrfs_bio *bbio = NULL;
 
-	if (bbio_ret && !(rw & (REQ_WRITE | REQ_DISCARD)))
-		stripes_allocated = 1;
-again:
-	if (bbio_ret) {
-		bbio = kzalloc(btrfs_bio_size(stripes_allocated),
-				GFP_NOFS);
-		if (!bbio)
-			return -ENOMEM;
-
-		atomic_set(&bbio->error, 0);
-	}
-
 	read_lock(&em_tree->lock);
 	em = lookup_extent_mapping(em_tree, logical, *length);
 	read_unlock(&em_tree->lock);
@@ -2939,32 +3645,6 @@ again:
 	if (mirror_num > map->num_stripes)
 		mirror_num = 0;
 
-	/* if our btrfs_bio struct is too small, back off and try again */
-	if (rw & REQ_WRITE) {
-		if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
-				 BTRFS_BLOCK_GROUP_DUP)) {
-			stripes_required = map->num_stripes;
-			max_errors = 1;
-		} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
-			stripes_required = map->sub_stripes;
-			max_errors = 1;
-		}
-	}
-	if (rw & REQ_DISCARD) {
-		if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
-				 BTRFS_BLOCK_GROUP_RAID1 |
-				 BTRFS_BLOCK_GROUP_DUP |
-				 BTRFS_BLOCK_GROUP_RAID10)) {
-			stripes_required = map->num_stripes;
-		}
-	}
-	if (bbio_ret && (rw & (REQ_WRITE | REQ_DISCARD)) &&
-	    stripes_allocated < stripes_required) {
-		stripes_allocated = map->num_stripes;
-		free_extent_map(em);
-		kfree(bbio);
-		goto again;
-	}
 	stripe_nr = offset;
 	/*
 	 * stripe_nr counts the total number of stripes we have to stride
@@ -2980,10 +3660,7 @@ again:
 
 	if (rw & REQ_DISCARD)
 		*length = min_t(u64, em->len - offset, *length);
-	else if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
-			      BTRFS_BLOCK_GROUP_RAID1 |
-			      BTRFS_BLOCK_GROUP_RAID10 |
-			      BTRFS_BLOCK_GROUP_DUP)) {
+	else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
 		/* we limit the length of each bio to what fits in a stripe */
 		*length = min_t(u64, em->len - offset,
 				map->stripe_len - stripe_offset);
@@ -3059,81 +3736,55 @@ again:
 	}
 	BUG_ON(stripe_index >= map->num_stripes);
 
+	bbio = kzalloc(btrfs_bio_size(num_stripes), GFP_NOFS);
+	if (!bbio) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	atomic_set(&bbio->error, 0);
+
 	if (rw & REQ_DISCARD) {
+		int factor = 0;
+		int sub_stripes = 0;
+		u64 stripes_per_dev = 0;
+		u32 remaining_stripes = 0;
+
+		if (map->type &
+		    (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
+			if (map->type & BTRFS_BLOCK_GROUP_RAID0)
+				sub_stripes = 1;
+			else
+				sub_stripes = map->sub_stripes;
+
+			factor = map->num_stripes / sub_stripes;
+			stripes_per_dev = div_u64_rem(stripe_nr_end -
+						      stripe_nr_orig,
+						      factor,
+						      &remaining_stripes);
+		}
+
 		for (i = 0; i < num_stripes; i++) {
 			bbio->stripes[i].physical =
 				map->stripes[stripe_index].physical +
 				stripe_offset + stripe_nr * map->stripe_len;
 			bbio->stripes[i].dev = map->stripes[stripe_index].dev;
 
-			if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
-				u64 stripes;
-				u32 last_stripe = 0;
-				int j;
-
-				div_u64_rem(stripe_nr_end - 1,
-					    map->num_stripes,
-					    &last_stripe);
-
-				for (j = 0; j < map->num_stripes; j++) {
-					u32 test;
-
-					div_u64_rem(stripe_nr_end - 1 - j,
-						    map->num_stripes, &test);
-					if (test == stripe_index)
-						break;
-				}
-				stripes = stripe_nr_end - 1 - j;
-				do_div(stripes, map->num_stripes);
-				bbio->stripes[i].length = map->stripe_len *
-					(stripes - stripe_nr + 1);
-
-				if (i == 0) {
-					bbio->stripes[i].length -=
-						stripe_offset;
-					stripe_offset = 0;
-				}
-				if (stripe_index == last_stripe)
-					bbio->stripes[i].length -=
-						stripe_end_offset;
-			} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
-				u64 stripes;
-				int j;
-				int factor = map->num_stripes /
-					     map->sub_stripes;
-				u32 last_stripe = 0;
-
-				div_u64_rem(stripe_nr_end - 1,
-					    factor, &last_stripe);
-				last_stripe *= map->sub_stripes;
-
-				for (j = 0; j < factor; j++) {
-					u32 test;
-
-					div_u64_rem(stripe_nr_end - 1 - j,
-						    factor, &test);
-
-					if (test ==
-					    stripe_index / map->sub_stripes)
-						break;
-				}
-				stripes = stripe_nr_end - 1 - j;
-				do_div(stripes, factor);
-				bbio->stripes[i].length = map->stripe_len *
-					(stripes - stripe_nr + 1);
-
-				if (i < map->sub_stripes) {
+			if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
+					 BTRFS_BLOCK_GROUP_RAID10)) {
+				bbio->stripes[i].length = stripes_per_dev *
+							  map->stripe_len;
+				if (i / sub_stripes < remaining_stripes)
+					bbio->stripes[i].length +=
+						map->stripe_len;
+				if (i < sub_stripes)
 					bbio->stripes[i].length -=
 						stripe_offset;
-					if (i == map->sub_stripes - 1)
-						stripe_offset = 0;
-				}
-				if (stripe_index >= last_stripe &&
-				    stripe_index <= (last_stripe +
-						     map->sub_stripes - 1)) {
+				if ((i / sub_stripes + 1) %
+				    sub_stripes == remaining_stripes)
 					bbio->stripes[i].length -=
 						stripe_end_offset;
-				}
+				if (i == sub_stripes - 1)
+					stripe_offset = 0;
 			} else
 				bbio->stripes[i].length = *length;
 
@@ -3155,15 +3806,22 @@ again:
 			stripe_index++;
 		}
 	}
-	if (bbio_ret) {
-		*bbio_ret = bbio;
-		bbio->num_stripes = num_stripes;
-		bbio->max_errors = max_errors;
-		bbio->mirror_num = mirror_num;
+
+	if (rw & REQ_WRITE) {
+		if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
+				 BTRFS_BLOCK_GROUP_RAID10 |
+				 BTRFS_BLOCK_GROUP_DUP)) {
+			max_errors = 1;
+		}
 	}
+
+	*bbio_ret = bbio;
+	bbio->num_stripes = num_stripes;
+	bbio->max_errors = max_errors;
+	bbio->mirror_num = mirror_num;
 out:
 	free_extent_map(em);
-	return 0;
+	return ret;
 }
 
 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
@@ -3304,7 +3962,7 @@ static noinline int schedule_bio(struct btrfs_root *root,
 	/* don't bother with additional async steps for reads, right now */
 	if (!(rw & REQ_WRITE)) {
 		bio_get(bio);
-		submit_bio(rw, bio);
+		btrfsic_submit_bio(rw, bio);
 		bio_put(bio);
 		return 0;
 	}
@@ -3399,7 +4057,7 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 			if (async_submit)
 				schedule_bio(root, dev, rw, bio);
 			else
-				submit_bio(rw, bio);
+				btrfsic_submit_bio(rw, bio);
 		} else {
 			bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
 			bio->bi_sector = logical >> 9;
@@ -3568,7 +4226,7 @@ static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
 	struct btrfs_fs_devices *fs_devices;
 	int ret;
 
-	mutex_lock(&uuid_mutex);
+	BUG_ON(!mutex_is_locked(&uuid_mutex));
 
 	fs_devices = root->fs_info->fs_devices->seed;
 	while (fs_devices) {
@@ -3606,7 +4264,6 @@ static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
 	fs_devices->seed = root->fs_info->fs_devices->seed;
 	root->fs_info->fs_devices->seed = fs_devices;
 out:
-	mutex_unlock(&uuid_mutex);
 	return ret;
 }
 
@@ -3749,6 +4406,9 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
 	if (!path)
 		return -ENOMEM;
 
+	mutex_lock(&uuid_mutex);
+	lock_chunks(root);
+
 	/* first we search for all of the device items, and then we
 	 * read in all of the chunk items.  This way we can create chunk
 	 * mappings that reference all of the devices that are afound
@@ -3799,6 +4459,9 @@ again:
 	}
 	ret = 0;
 error:
+	unlock_chunks(root);
+	mutex_unlock(&uuid_mutex);
+
 	btrfs_free_path(path);
 	return ret;
 }
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 78f2d4d4f37..19ac95048b8 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -186,6 +186,51 @@ struct map_lookup {
 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
 			    (sizeof(struct btrfs_bio_stripe) * (n)))
 
+/*
+ * Restriper's general type filter
+ */
+#define BTRFS_BALANCE_DATA		(1ULL << 0)
+#define BTRFS_BALANCE_SYSTEM		(1ULL << 1)
+#define BTRFS_BALANCE_METADATA		(1ULL << 2)
+
+#define BTRFS_BALANCE_TYPE_MASK		(BTRFS_BALANCE_DATA |	    \
+					 BTRFS_BALANCE_SYSTEM |	    \
+					 BTRFS_BALANCE_METADATA)
+
+#define BTRFS_BALANCE_FORCE		(1ULL << 3)
+#define BTRFS_BALANCE_RESUME		(1ULL << 4)
+
+/*
+ * Balance filters
+ */
+#define BTRFS_BALANCE_ARGS_PROFILES	(1ULL << 0)
+#define BTRFS_BALANCE_ARGS_USAGE	(1ULL << 1)
+#define BTRFS_BALANCE_ARGS_DEVID	(1ULL << 2)
+#define BTRFS_BALANCE_ARGS_DRANGE	(1ULL << 3)
+#define BTRFS_BALANCE_ARGS_VRANGE	(1ULL << 4)
+
+/*
+ * Profile changing flags.  When SOFT is set we won't relocate chunk if
+ * it already has the target profile (even though it may be
+ * half-filled).
+ */
+#define BTRFS_BALANCE_ARGS_CONVERT	(1ULL << 8)
+#define BTRFS_BALANCE_ARGS_SOFT		(1ULL << 9)
+
+struct btrfs_balance_args;
+struct btrfs_balance_progress;
+struct btrfs_balance_control {
+	struct btrfs_fs_info *fs_info;
+
+	struct btrfs_balance_args data;
+	struct btrfs_balance_args meta;
+	struct btrfs_balance_args sys;
+
+	u64 flags;
+
+	struct btrfs_balance_progress stat;
+};
+
 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 				   u64 end, u64 *length);
 
@@ -228,9 +273,12 @@ struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
 				       u8 *uuid, u8 *fsid);
 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size);
 int btrfs_init_new_device(struct btrfs_root *root, char *path);
-int btrfs_balance(struct btrfs_root *dev_root);
+int btrfs_balance(struct btrfs_balance_control *bctl,
+		  struct btrfs_ioctl_balance_args *bargs);
+int btrfs_recover_balance(struct btrfs_root *tree_root);
+int btrfs_pause_balance(struct btrfs_fs_info *fs_info);
+int btrfs_cancel_balance(struct btrfs_fs_info *fs_info);
 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset);
-int find_free_dev_extent(struct btrfs_trans_handle *trans,
-			 struct btrfs_device *device, u64 num_bytes,
+int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 			 u64 *start, u64 *max_avail);
 #endif
diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index 3848b04e310..e7a5659087e 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -200,7 +200,7 @@ int __btrfs_setxattr(struct btrfs_trans_handle *trans,
 	ret = btrfs_update_inode(trans, root, inode);
 	BUG_ON(ret);
 out:
-	btrfs_end_transaction_throttle(trans, root);
+	btrfs_end_transaction(trans, root);
 	return ret;
 }