From 125ccb0ae6806dbec31abf4a85448971df3b4e39 Mon Sep 17 00:00:00 2001
From: Li Zefan <lizf@cn.fujitsu.com>
Date: Thu, 8 Dec 2011 15:07:24 +0800
Subject: Btrfs: don't pass a trans handle unnecessarily in volumes.c

Some functions never use the transaction handle passed to them.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 fs/btrfs/volumes.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 78f2d4d4f37..c1701ec9d49 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -230,7 +230,6 @@ 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_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
-- 
cgit v1.2.3-70-g09d2


From c9e9f97bdfb64d06e9520f8e4f37674ac21cc9bc Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:47 +0200
Subject: Btrfs: add basic restriper infrastructure

Add basic restriper infrastructure: extended balancing ioctl and all
related ioctl data structures, add data structure for tracking
restriper's state to fs_info, etc.  The semantics of the old balancing
ioctl are fully preserved.

Explicitly disallow any volume operations when balance is in progress.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/ctree.h   |   6 +++
 fs/btrfs/disk-io.c |   4 ++
 fs/btrfs/ioctl.c   | 135 ++++++++++++++++++++++++++++++++++++++++++++++-------
 fs/btrfs/ioctl.h   |  43 +++++++++++++++++
 fs/btrfs/volumes.c | 120 +++++++++++++++++++++++++++++++++++++----------
 fs/btrfs/volumes.h |  14 +++++-
 6 files changed, 281 insertions(+), 41 deletions(-)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3f8f11e18b5..c4d98c8df5c 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -934,6 +934,7 @@ 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];
@@ -1159,6 +1160,11 @@ struct btrfs_fs_info {
 	u64 avail_metadata_alloc_bits;
 	u64 avail_system_alloc_bits;
 
+	/* restriper state */
+	spinlock_t balance_lock;
+	struct mutex balance_mutex;
+	struct btrfs_balance_control *balance_ctl;
+
 	unsigned data_chunk_allocations;
 	unsigned metadata_ratio;
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index ce9d0fb3627..190a1b24c90 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2002,6 +2002,10 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	init_rwsem(&fs_info->scrub_super_lock);
 	fs_info->scrub_workers_refcnt = 0;
 
+	spin_lock_init(&fs_info->balance_lock);
+	mutex_init(&fs_info->balance_mutex);
+	fs_info->balance_ctl = NULL;
+
 	sb->s_blocksize = 4096;
 	sb->s_blocksize_bits = blksize_bits(4096);
 	sb->s_bdi = &fs_info->bdi;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index c04f02c7d5b..d838d2cfb94 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1203,13 +1203,21 @@ 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 +1234,7 @@ 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 +1249,7 @@ 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 +1258,7 @@ 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 +1267,11 @@ 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 +1284,7 @@ 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 +1292,10 @@ 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;
 }
 
@@ -2052,14 +2061,25 @@ 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 +2094,25 @@ 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;
 }
 
@@ -3034,6 +3065,76 @@ out:
 	return ret;
 }
 
+void update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
+			       struct btrfs_ioctl_balance_args *bargs)
+{
+	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
+
+	bargs->flags = bctl->flags;
+
+	memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
+	memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
+	memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
+}
+
+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;
+		}
+	} else {
+		bargs = NULL;
+	}
+
+	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;
+	}
+
+	ret = btrfs_balance(bctl, bargs);
+	/*
+	 * bctl is freed in __cancel_balance
+	 */
+	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;
+}
+
 long btrfs_ioctl(struct file *file, unsigned int
 		cmd, unsigned long arg)
 {
@@ -3078,7 +3179,7 @@ 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 +3211,8 @@ 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);
 	}
 
 	return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 252ae9915de..c8b37d2c0d7 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -109,6 +109,47 @@ struct btrfs_ioctl_fs_info_args {
 	__u64 reserved[124];			/* pad to 1k */
 };
 
+/*
+ * 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 */
+};
+
+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 +313,8 @@ 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_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/volumes.c b/fs/btrfs/volumes.c
index d5fdee56777..9fc06e6bc51 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1282,7 +1282,6 @@ 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 +1451,6 @@ 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:
@@ -1629,7 +1627,6 @@ 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;
 	/*
@@ -1757,8 +1754,7 @@ 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 +1762,7 @@ 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 +2073,35 @@ error:
 	return ret;
 }
 
+/*
+ * 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);
+}
+
 static u64 div_factor(u64 num, int factor)
 {
 	if (factor == 10)
@@ -2086,29 +2111,23 @@ 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_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_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;
+	int ret;
+	int enospc_errors = 0;
 
 	/* 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);
@@ -2151,12 +2170,14 @@ 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;
+		}
 
 		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 				      path->slots[0]);
@@ -2174,12 +2195,63 @@ int btrfs_balance(struct btrfs_root *dev_root)
 					   found_key.offset);
 		if (ret && ret != -ENOSPC)
 			goto error;
+		if (ret == -ENOSPC)
+			enospc_errors++;
 		key.offset = found_key.offset - 1;
 	}
-	ret = 0;
+
 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 void __cancel_balance(struct btrfs_fs_info *fs_info)
+{
+	unset_balance_control(fs_info);
+}
+
+void update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
+			       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;
+	int ret;
+
+	if (btrfs_fs_closing(fs_info)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	set_balance_control(bctl);
+
+	mutex_unlock(&fs_info->balance_mutex);
+
+	ret = __btrfs_balance(fs_info);
+
+	mutex_lock(&fs_info->balance_mutex);
+
+	if (bargs) {
+		memset(bargs, 0, sizeof(*bargs));
+		update_ioctl_balance_args(fs_info, bargs);
+	}
+
+	__cancel_balance(fs_info);
+
+	return ret;
+out:
+	kfree(bctl);
 	return ret;
 }
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 78f2d4d4f37..88258238528 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -186,6 +186,17 @@ struct map_lookup {
 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
 			    (sizeof(struct btrfs_bio_stripe) * (n)))
 
+struct btrfs_balance_args;
+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;
+};
+
 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 				   u64 end, u64 *length);
 
@@ -228,7 +239,8 @@ 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_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,
-- 
cgit v1.2.3-70-g09d2


From f43ffb60fd94e98be02780944e182ade6653b916 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:47 +0200
Subject: Btrfs: add basic infrastructure for selective balancing

This allows to have a separate set of filters for each chunk type
(data,meta,sys).  The code however is generic and switch on chunk type
is only done once.

This commit also adds a type filter: it allows to balance for example
meta and system chunks w/o touching data ones.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/ioctl.c   |  3 +++
 fs/btrfs/volumes.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
 fs/btrfs/volumes.h | 11 ++++++++++
 3 files changed, 71 insertions(+), 2 deletions(-)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d838d2cfb94..29b3a94933f 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3116,6 +3116,9 @@ static long btrfs_ioctl_balance(struct btrfs_root *root, void __user *arg)
 		memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
 
 		bctl->flags = bargs->flags;
+	} else {
+		/* balance everything - no filters */
+		bctl->flags |= BTRFS_BALANCE_TYPE_MASK;
 	}
 
 	ret = btrfs_balance(bctl, bargs);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 9fc06e6bc51..91bbf6e774c 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2102,6 +2102,30 @@ static void unset_balance_control(struct btrfs_fs_info *fs_info)
 	kfree(bctl);
 }
 
+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;
+
+	return 1;
+}
+
 static u64 div_factor(u64 num, int factor)
 {
 	if (factor == 10)
@@ -2119,10 +2143,13 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 	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_key found_key;
 	struct btrfs_trans_handle *trans;
+	struct extent_buffer *leaf;
+	int slot;
 	int ret;
 	int enospc_errors = 0;
 
@@ -2179,8 +2206,10 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 			break;
 		}
 
-		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
-				      path->slots[0]);
+		leaf = path->nodes[0];
+		slot = path->slots[0];
+		btrfs_item_key_to_cpu(leaf, &found_key, slot);
+
 		if (found_key.objectid != key.objectid)
 			break;
 
@@ -2188,7 +2217,14 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 		if (found_key.offset == 0)
 			break;
 
+		chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
+
+		ret = should_balance_chunk(chunk_root, leaf, chunk,
+					   found_key.offset);
 		btrfs_release_path(path);
+		if (!ret)
+			goto loop;
+
 		ret = btrfs_relocate_chunk(chunk_root,
 					   chunk_root->root_key.objectid,
 					   found_key.objectid,
@@ -2197,6 +2233,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 			goto error;
 		if (ret == -ENOSPC)
 			enospc_errors++;
+loop:
 		key.offset = found_key.offset - 1;
 	}
 
@@ -2227,6 +2264,7 @@ 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)) {
@@ -2234,6 +2272,23 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 		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;
+		}
+	}
+
 	set_balance_control(bctl);
 
 	mutex_unlock(&fs_info->balance_mutex);
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 88258238528..003e5421606 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -186,6 +186,17 @@ 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)
+
 struct btrfs_balance_args;
 struct btrfs_balance_control {
 	struct btrfs_fs_info *fs_info;
-- 
cgit v1.2.3-70-g09d2


From ed25e9b26f898d8d63ae4a836489f1923534143b Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:47 +0200
Subject: Btrfs: profiles filter

Select chunks based on a given profile mask.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/volumes.c | 24 ++++++++++++++++++++++++
 fs/btrfs/volumes.h |  4 ++++
 2 files changed, 28 insertions(+)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 91bbf6e774c..447bd422d86 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2102,6 +2102,24 @@ static void unset_balance_control(struct btrfs_fs_info *fs_info)
 	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 int should_balance_chunk(struct btrfs_root *root,
 				struct extent_buffer *leaf,
 				struct btrfs_chunk *chunk, u64 chunk_offset)
@@ -2123,6 +2141,12 @@ static int should_balance_chunk(struct btrfs_root *root,
 	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;
+	}
+
 	return 1;
 }
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 003e5421606..fb20d774044 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -196,6 +196,10 @@ struct map_lookup {
 #define BTRFS_BALANCE_TYPE_MASK		(BTRFS_BALANCE_DATA |	    \
 					 BTRFS_BALANCE_SYSTEM |	    \
 					 BTRFS_BALANCE_METADATA)
+/*
+ * Balance filters
+ */
+#define BTRFS_BALANCE_ARGS_PROFILES	(1ULL << 0)
 
 struct btrfs_balance_args;
 struct btrfs_balance_control {
-- 
cgit v1.2.3-70-g09d2


From 5ce5b3c0916ba3a2e34cf648b94044adc5ef9e76 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:47 +0200
Subject: Btrfs: usage filter

Select chunks that are less than X percent full.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/volumes.c | 36 ++++++++++++++++++++++++++++++++++++
 fs/btrfs/volumes.h |  1 +
 2 files changed, 37 insertions(+)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 447bd422d86..b858242374d 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2120,6 +2120,36 @@ static int chunk_profiles_filter(u64 chunk_profile,
 	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 should_balance_chunk(struct btrfs_root *root,
 				struct extent_buffer *leaf,
 				struct btrfs_chunk *chunk, u64 chunk_offset)
@@ -2147,6 +2177,12 @@ static int should_balance_chunk(struct btrfs_root *root,
 		return 0;
 	}
 
+	/* usage filter */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
+	    chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
+		return 0;
+	}
+
 	return 1;
 }
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index fb20d774044..eee77fcf812 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -200,6 +200,7 @@ struct map_lookup {
  * Balance filters
  */
 #define BTRFS_BALANCE_ARGS_PROFILES	(1ULL << 0)
+#define BTRFS_BALANCE_ARGS_USAGE	(1ULL << 1)
 
 struct btrfs_balance_args;
 struct btrfs_balance_control {
-- 
cgit v1.2.3-70-g09d2


From 409d404b461afa9738619f249fd7f62a366b68c2 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:47 +0200
Subject: Btrfs: devid filter

Relocate chunks which have at least one stripe located on a device with
devid X.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/volumes.c | 23 +++++++++++++++++++++++
 fs/btrfs/volumes.h |  1 +
 2 files changed, 24 insertions(+)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index b858242374d..9ff5cd09a25 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2150,6 +2150,23 @@ static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
 	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;
+}
+
 static int should_balance_chunk(struct btrfs_root *root,
 				struct extent_buffer *leaf,
 				struct btrfs_chunk *chunk, u64 chunk_offset)
@@ -2183,6 +2200,12 @@ static int should_balance_chunk(struct btrfs_root *root,
 		return 0;
 	}
 
+	/* devid filter */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
+	    chunk_devid_filter(leaf, chunk, bargs)) {
+		return 0;
+	}
+
 	return 1;
 }
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index eee77fcf812..7cfec03c29b 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -201,6 +201,7 @@ struct map_lookup {
  */
 #define BTRFS_BALANCE_ARGS_PROFILES	(1ULL << 0)
 #define BTRFS_BALANCE_ARGS_USAGE	(1ULL << 1)
+#define BTRFS_BALANCE_ARGS_DEVID	(1ULL << 2)
 
 struct btrfs_balance_args;
 struct btrfs_balance_control {
-- 
cgit v1.2.3-70-g09d2


From 94e60d5a5c4b98a32b1077dec88df09ada712376 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:48 +0200
Subject: Btrfs: devid subset filter

Select chunks which have at least one byte of at least one stripe
located on a device with devid X in a given [pstart,pend) physical
address range.

This filter only works when devid filter is turned on.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/volumes.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/volumes.h |  1 +
 2 files changed, 47 insertions(+)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 9ff5cd09a25..c60071a448a 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2167,6 +2167,46 @@ static int chunk_devid_filter(struct extent_buffer *leaf,
 	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;
+}
+
 static int should_balance_chunk(struct btrfs_root *root,
 				struct extent_buffer *leaf,
 				struct btrfs_chunk *chunk, u64 chunk_offset)
@@ -2206,6 +2246,12 @@ static int should_balance_chunk(struct btrfs_root *root,
 		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;
+	}
+
 	return 1;
 }
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 7cfec03c29b..844b08e388f 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -202,6 +202,7 @@ struct map_lookup {
 #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)
 
 struct btrfs_balance_args;
 struct btrfs_balance_control {
-- 
cgit v1.2.3-70-g09d2


From ea67176ae8c024f64d85ec33873e5eadf1af7247 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:48 +0200
Subject: Btrfs: virtual address space subset filter

Select chunks which have at least one byte located inside a given
[vstart, vend) virtual address space range.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/volumes.c | 20 ++++++++++++++++++++
 fs/btrfs/volumes.h |  1 +
 2 files changed, 21 insertions(+)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index c60071a448a..e86c9e4fe51 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2207,6 +2207,20 @@ static int chunk_drange_filter(struct extent_buffer *leaf,
 	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 should_balance_chunk(struct btrfs_root *root,
 				struct extent_buffer *leaf,
 				struct btrfs_chunk *chunk, u64 chunk_offset)
@@ -2252,6 +2266,12 @@ static int should_balance_chunk(struct btrfs_root *root,
 		return 0;
 	}
 
+	/* vrange filter */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
+	    chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
+		return 0;
+	}
+
 	return 1;
 }
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 844b08e388f..eac26c35931 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -203,6 +203,7 @@ struct map_lookup {
 #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)
 
 struct btrfs_balance_args;
 struct btrfs_balance_control {
-- 
cgit v1.2.3-70-g09d2


From e4d8ec0f65b91bfb4984a4927632ded95f9825ad Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:48 +0200
Subject: Btrfs: implement online profile changing

Profile changing is done by launching a balance with
BTRFS_BALANCE_CONVERT bits set and target fields of respective
btrfs_balance_args structs initialized.  Profile reducing code in this
case will pick restriper's target profile if it's available instead of
doing a blind reduce.  If target profile is not yet available it goes
back to a plain reduce.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/extent-tree.c | 56 +++++++++++++++++++++++++++++++++++++++-
 fs/btrfs/volumes.c     | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/volumes.h     |  5 ++++
 3 files changed, 129 insertions(+), 1 deletion(-)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a1a18ea7b6c..e6a832e3e64 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3030,7 +3030,9 @@ static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
 /*
  * @flags: available profiles in extended format (see ctree.h)
  *
- * Returns reduced profile in chunk format.
+ * 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)
 {
@@ -3042,6 +3044,34 @@ 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)
@@ -3065,6 +3095,7 @@ u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
 		flags &= ~BTRFS_BLOCK_GROUP_RAID0;
 	}
 
+out:
 	/* extended -> chunk profile */
 	flags &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
 	return flags;
@@ -6795,6 +6826,29 @@ 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
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e86c9e4fe51..f08210e8333 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2438,6 +2438,75 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 		}
 	}
 
+	/*
+	 * 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:
 	set_balance_control(bctl);
 
 	mutex_unlock(&fs_info->balance_mutex);
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index eac26c35931..79ee9c32456 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -196,6 +196,9 @@ struct map_lookup {
 #define BTRFS_BALANCE_TYPE_MASK		(BTRFS_BALANCE_DATA |	    \
 					 BTRFS_BALANCE_SYSTEM |	    \
 					 BTRFS_BALANCE_METADATA)
+
+#define BTRFS_BALANCE_FORCE		(1ULL << 3)
+
 /*
  * Balance filters
  */
@@ -205,6 +208,8 @@ struct map_lookup {
 #define BTRFS_BALANCE_ARGS_DRANGE	(1ULL << 3)
 #define BTRFS_BALANCE_ARGS_VRANGE	(1ULL << 4)
 
+#define BTRFS_BALANCE_ARGS_CONVERT	(1ULL << 8)
+
 struct btrfs_balance_args;
 struct btrfs_balance_control {
 	struct btrfs_fs_info *fs_info;
-- 
cgit v1.2.3-70-g09d2


From cfa4c961cc69ffb7bda450972320a25cbd413e19 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:48 +0200
Subject: Btrfs: soft profile changing mode (aka soft convert)

When doing convert from one profile to another if soft mode is on
restriper won't touch chunks that already have the profile we are
converting to.  This is useful if e.g. half of the FS was converted
earlier.

The soft mode switch is (like every other filter) per-type.  This means
that we can convert for example meta chunks the "hard" way while
converting data chunks selectively with soft switch.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/volumes.c | 23 +++++++++++++++++++++++
 fs/btrfs/volumes.h |  6 ++++++
 2 files changed, 29 insertions(+)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index f08210e8333..98b4067017f 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2221,6 +2221,23 @@ static int chunk_vrange_filter(struct extent_buffer *leaf,
 	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)
@@ -2272,6 +2289,12 @@ static int should_balance_chunk(struct btrfs_root *root,
 		return 0;
 	}
 
+	/* soft profile changing mode */
+	if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
+	    chunk_soft_convert_filter(chunk_type, bargs)) {
+		return 0;
+	}
+
 	return 1;
 }
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 79ee9c32456..6c143c98017 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -208,7 +208,13 @@ struct map_lookup {
 #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_control {
-- 
cgit v1.2.3-70-g09d2


From 596410151ed71819b9e8a8018c6c9992796b256d Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:48 +0200
Subject: Btrfs: recover balance on mount

On mount, if balance item is found, resume balance in a separate
kernel thread.

Try to be smart to continue roughly where previous balance (or convert)
was interrupted.  For chunk types that were being converted to some
profile we turn on soft convert, in case of a simple balance we turn on
usage filter and relocate only less-than-90%-full chunks of that type.
These are just heuristics but they help quite a bit, and can be improved
in future.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/disk-io.c |   4 ++
 fs/btrfs/volumes.c | 135 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 fs/btrfs/volumes.h |   2 +
 3 files changed, 139 insertions(+), 2 deletions(-)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 190a1b24c90..eb7a11ac5b7 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2427,6 +2427,10 @@ 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);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 4c60ca0ae90..17e565388de 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"
@@ -2164,6 +2165,46 @@ out:
 	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
@@ -2626,10 +2667,18 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 
 do_balance:
 	ret = insert_balance_item(fs_info->tree_root, bctl);
-	if (ret)
+	if (ret && ret != -EEXIST)
 		goto out;
 
-	set_balance_control(bctl);
+	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);
+	}
 
 	mutex_unlock(&fs_info->balance_mutex);
 
@@ -2646,7 +2695,89 @@ do_balance:
 
 	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;
+
+	mutex_lock(&fs_info->volume_mutex);
+	mutex_lock(&fs_info->balance_mutex);
+
+	set_balance_control(bctl);
+
+	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;
 }
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 6c143c98017..cd25ea58ec3 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -198,6 +198,7 @@ struct map_lookup {
 					 BTRFS_BALANCE_METADATA)
 
 #define BTRFS_BALANCE_FORCE		(1ULL << 3)
+#define BTRFS_BALANCE_RESUME		(1ULL << 4)
 
 /*
  * Balance filters
@@ -271,6 +272,7 @@ 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_balance_control *bctl,
 		  struct btrfs_ioctl_balance_args *bargs);
+int btrfs_recover_balance(struct btrfs_root *tree_root);
 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,
-- 
cgit v1.2.3-70-g09d2


From 837d5b6e46d1a4af5b6cc8f2fe83cb5de79a2961 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:49 +0200
Subject: Btrfs: allow for pausing restriper

Implement an ioctl for pausing restriper.  This pauses the relocation,
but balance is still considered to be "in progress": balance item is
not deleted, other volume operations cannot be started, etc.  If paused
in the middle of profile changing operation we will continue making
allocations with the target profile.

Add a hook to close_ctree() to pause restriper and free its data
structures on unmount.  (It's safe to unmount when restriper is in
"paused" state, we will resume with the same parameters on the next
mount)

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/ctree.h   |  4 ++++
 fs/btrfs/disk-io.c |  6 ++++++
 fs/btrfs/ioctl.c   | 28 +++++++++++++++++++++++++++-
 fs/btrfs/ioctl.h   |  7 +++++++
 fs/btrfs/volumes.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++--
 fs/btrfs/volumes.h |  1 +
 6 files changed, 94 insertions(+), 3 deletions(-)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 99eb2bcd9aa..1afda75d541 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1214,7 +1214,10 @@ struct btrfs_fs_info {
 	/* restriper state */
 	spinlock_t balance_lock;
 	struct mutex balance_mutex;
+	atomic_t balance_running;
+	atomic_t balance_pause_req;
 	struct btrfs_balance_control *balance_ctl;
+	wait_queue_head_t balance_wait_q;
 
 	unsigned data_chunk_allocations;
 	unsigned metadata_ratio;
@@ -2658,6 +2661,7 @@ 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);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index eb7a11ac5b7..8ce83740780 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2004,7 +2004,10 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 
 	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);
 	fs_info->balance_ctl = NULL;
+	init_waitqueue_head(&fs_info->balance_wait_q);
 
 	sb->s_blocksize = 4096;
 	sb->s_blocksize_bits = blksize_bits(4096);
@@ -2980,6 +2983,9 @@ 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 */
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 29b3a94933f..f572c53dda4 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3072,6 +3072,11 @@ void update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
 
 	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;
+
 	memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
 	memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
 	memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
@@ -3103,6 +3108,11 @@ static long btrfs_ioctl_balance(struct btrfs_root *root, void __user *arg)
 		bargs = NULL;
 	}
 
+	if (fs_info->balance_ctl) {
+		ret = -EINPROGRESS;
+		goto out_bargs;
+	}
+
 	bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
 	if (!bctl) {
 		ret = -ENOMEM;
@@ -3123,7 +3133,8 @@ static long btrfs_ioctl_balance(struct btrfs_root *root, void __user *arg)
 
 	ret = btrfs_balance(bctl, bargs);
 	/*
-	 * bctl is freed in __cancel_balance
+	 * 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)))
@@ -3138,6 +3149,19 @@ out:
 	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);
+	}
+
+	return -EINVAL;
+}
+
 long btrfs_ioctl(struct file *file, unsigned int
 		cmd, unsigned long arg)
 {
@@ -3216,6 +3240,8 @@ long btrfs_ioctl(struct file *file, unsigned int
 		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);
 	}
 
 	return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index c8b37d2c0d7..e972e11a8d7 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -109,6 +109,9 @@ struct btrfs_ioctl_fs_info_args {
 	__u64 reserved[124];			/* pad to 1k */
 };
 
+/* balance control ioctl modes */
+#define BTRFS_BALANCE_CTL_PAUSE		1
+
 /*
  * this is packed, because it should be exactly the same as its disk
  * byte order counterpart (struct btrfs_disk_balance_args)
@@ -137,6 +140,9 @@ struct btrfs_balance_progress {
 	__u64 completed;	/* # of chunks relocated so far */
 };
 
+#define BTRFS_BALANCE_STATE_RUNNING	(1ULL << 0)
+#define BTRFS_BALANCE_STATE_PAUSE_REQ	(1ULL << 1)
+
 struct btrfs_ioctl_balance_args {
 	__u64 flags;				/* in/out */
 	__u64 state;				/* out */
@@ -315,6 +321,7 @@ struct btrfs_ioctl_logical_ino_args {
 			       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_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/volumes.c b/fs/btrfs/volumes.c
index e0160607e6e..d32660ce753 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2492,6 +2492,11 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 	key.type = BTRFS_CHUNK_ITEM_KEY;
 
 	while (1) {
+		if (atomic_read(&fs_info->balance_pause_req)) {
+			ret = -ECANCELED;
+			goto error;
+		}
+
 		ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
 		if (ret < 0)
 			goto error;
@@ -2553,6 +2558,11 @@ error:
 	return ret;
 }
 
+static inline int balance_need_close(struct btrfs_fs_info *fs_info)
+{
+	return atomic_read(&fs_info->balance_pause_req) == 0;
+}
+
 static void __cancel_balance(struct btrfs_fs_info *fs_info)
 {
 	int ret;
@@ -2575,7 +2585,8 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 	u64 allowed;
 	int ret;
 
-	if (btrfs_fs_closing(fs_info)) {
+	if (btrfs_fs_closing(fs_info) ||
+	    atomic_read(&fs_info->balance_pause_req)) {
 		ret = -EINVAL;
 		goto out;
 	}
@@ -2680,18 +2691,25 @@ do_balance:
 		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, bargs);
 	}
 
-	__cancel_balance(fs_info);
+	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:
@@ -2785,6 +2803,35 @@ out:
 	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;
+}
+
 /*
  * shrinking a device means finding all of the device extents past
  * the new size, and then following the back refs to the chunks.
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index cd25ea58ec3..80953afb12b 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -273,6 +273,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *path);
 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_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,
-- 
cgit v1.2.3-70-g09d2


From a7e99c691af553fc15ac46a51f130b7c59a65f76 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:49 +0200
Subject: Btrfs: allow for canceling restriper

Implement an ioctl for canceling restriper.  Currently we wait until
relocation of the current block group is finished, in future this can be
done by triggering a commit.  Balance item is deleted and no memory
about the interrupted balance is kept.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/ctree.h   |  1 +
 fs/btrfs/disk-io.c |  1 +
 fs/btrfs/ioctl.c   |  4 ++++
 fs/btrfs/ioctl.h   |  2 ++
 fs/btrfs/volumes.c | 47 ++++++++++++++++++++++++++++++++++++++++++++---
 fs/btrfs/volumes.h |  1 +
 6 files changed, 53 insertions(+), 3 deletions(-)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 1afda75d541..dfc136cc07d 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1216,6 +1216,7 @@ struct btrfs_fs_info {
 	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;
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 8ce83740780..c23b82d8ec0 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2006,6 +2006,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	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);
 
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index f572c53dda4..60852217ce9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3076,6 +3076,8 @@ void update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
 		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));
@@ -3157,6 +3159,8 @@ static long btrfs_ioctl_balance_ctl(struct btrfs_root *root, int cmd)
 	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;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index e972e11a8d7..cd19d10794b 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -111,6 +111,7 @@ struct btrfs_ioctl_fs_info_args {
 
 /* 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
@@ -142,6 +143,7 @@ struct btrfs_balance_progress {
 
 #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 */
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index d32660ce753..c32667318ae 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2492,7 +2492,8 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 	key.type = BTRFS_CHUNK_ITEM_KEY;
 
 	while (1) {
-		if (atomic_read(&fs_info->balance_pause_req)) {
+		if (atomic_read(&fs_info->balance_pause_req) ||
+		    atomic_read(&fs_info->balance_cancel_req)) {
 			ret = -ECANCELED;
 			goto error;
 		}
@@ -2560,7 +2561,10 @@ error:
 
 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
 {
-	return atomic_read(&fs_info->balance_pause_req) == 0;
+	/* 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)
@@ -2586,7 +2590,8 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 	int ret;
 
 	if (btrfs_fs_closing(fs_info) ||
-	    atomic_read(&fs_info->balance_pause_req)) {
+	    atomic_read(&fs_info->balance_pause_req) ||
+	    atomic_read(&fs_info->balance_cancel_req)) {
 		ret = -EINVAL;
 		goto out;
 	}
@@ -2832,6 +2837,42 @@ int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
 	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.
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 80953afb12b..caa9abd218e 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -274,6 +274,7 @@ 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,
-- 
cgit v1.2.3-70-g09d2


From 19a39dce3b9bf0244d19a446718ad6f7605ff099 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Mon, 16 Jan 2012 22:04:49 +0200
Subject: Btrfs: add balance progress reporting

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
 fs/btrfs/ioctl.c   | 45 ++++++++++++++++++++++++++++++++++++++++++++-
 fs/btrfs/ioctl.h   |  2 ++
 fs/btrfs/volumes.c | 39 +++++++++++++++++++++++++++++++++++----
 fs/btrfs/volumes.h |  3 +++
 4 files changed, 84 insertions(+), 5 deletions(-)

(limited to 'fs/btrfs/volumes.h')

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 85e546ffe3c..1e7a9bac31a 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3065,7 +3065,7 @@ out:
 	return ret;
 }
 
-void update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
+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;
@@ -3082,6 +3082,14 @@ void update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
 	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)
@@ -3181,6 +3189,39 @@ static long btrfs_ioctl_balance_ctl(struct btrfs_root *root, int cmd)
 	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)
 {
@@ -3261,6 +3302,8 @@ long btrfs_ioctl(struct file *file, unsigned int
 		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 cd19d10794b..4f69028a68c 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -324,6 +324,8 @@ struct btrfs_ioctl_logical_ino_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/volumes.c b/fs/btrfs/volumes.c
index c32667318ae..d73439b4d7d 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2441,6 +2441,7 @@ static u64 div_factor(u64 num, int factor)
 
 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 {
+	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;
@@ -2456,6 +2457,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 	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;
@@ -2487,12 +2489,18 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 		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 (atomic_read(&fs_info->balance_pause_req) ||
+		if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
 		    atomic_read(&fs_info->balance_cancel_req)) {
 			ret = -ECANCELED;
 			goto error;
@@ -2529,24 +2537,47 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 
 		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)
+		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;
 	}
 
+	if (counting) {
+		btrfs_release_path(path);
+		counting = false;
+		goto again;
+	}
 error:
 	btrfs_free_path(path);
 	if (enospc_errors) {
@@ -2576,7 +2607,7 @@ static void __cancel_balance(struct btrfs_fs_info *fs_info)
 	BUG_ON(ret);
 }
 
-void update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
+void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
 			       struct btrfs_ioctl_balance_args *bargs);
 
 /*
@@ -2706,7 +2737,7 @@ do_balance:
 
 	if (bargs) {
 		memset(bargs, 0, sizeof(*bargs));
-		update_ioctl_balance_args(fs_info, bargs);
+		update_ioctl_balance_args(fs_info, 0, bargs);
 	}
 
 	if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index caa9abd218e..6faec9dd1f9 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -218,6 +218,7 @@ struct map_lookup {
 #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;
 
@@ -226,6 +227,8 @@ struct btrfs_balance_control {
 	struct btrfs_balance_args sys;
 
 	u64 flags;
+
+	struct btrfs_balance_progress stat;
 };
 
 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
-- 
cgit v1.2.3-70-g09d2