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authorStefan Behrens <sbehrens@giantdisaster.de>2013-08-15 17:11:21 +0200
committerChris Mason <chris.mason@fusionio.com>2013-09-01 08:15:56 -0400
commit803b2f54fb4faf6d76fca43e59bcc555d9713cd4 (patch)
treef5e5c56d186aa1829aaedb652756ec8f4644e05b /fs/btrfs/volumes.c
parentdd5f9615fc5c5e8d3751aab3a17b92768fb1ce70 (diff)
Btrfs: fill UUID tree initially
When the UUID tree is initially created, a task is spawned that walks through the root tree. For each found subvolume root_item, the uuid and received_uuid entries in the UUID tree are added. This is such a quick operation so that in case somebody wants to unmount the filesystem while the task is still running, the unmount is delayed until the UUID tree building task is finished. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Diffstat (limited to 'fs/btrfs/volumes.c')
-rw-r--r--fs/btrfs/volumes.c151
1 files changed, 150 insertions, 1 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e084218c09d..4066803fe76 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -26,6 +26,7 @@
#include <linux/ratelimit.h>
#include <linux/kthread.h>
#include <linux/raid/pq.h>
+#include <linux/semaphore.h>
#include <asm/div64.h>
#include "compat.h"
#include "ctree.h"
@@ -3429,11 +3430,146 @@ int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
return 0;
}
+static int btrfs_uuid_scan_kthread(void *data)
+{
+ struct btrfs_fs_info *fs_info = data;
+ struct btrfs_root *root = fs_info->tree_root;
+ struct btrfs_key key;
+ struct btrfs_key max_key;
+ struct btrfs_path *path = NULL;
+ int ret = 0;
+ struct extent_buffer *eb;
+ int slot;
+ struct btrfs_root_item root_item;
+ u32 item_size;
+ struct btrfs_trans_handle *trans;
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ key.objectid = 0;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = 0;
+
+ max_key.objectid = (u64)-1;
+ max_key.type = BTRFS_ROOT_ITEM_KEY;
+ max_key.offset = (u64)-1;
+
+ path->keep_locks = 1;
+
+ while (1) {
+ ret = btrfs_search_forward(root, &key, &max_key, path, 0);
+ if (ret) {
+ if (ret > 0)
+ ret = 0;
+ break;
+ }
+
+ if (key.type != BTRFS_ROOT_ITEM_KEY ||
+ (key.objectid < BTRFS_FIRST_FREE_OBJECTID &&
+ key.objectid != BTRFS_FS_TREE_OBJECTID) ||
+ key.objectid > BTRFS_LAST_FREE_OBJECTID)
+ goto skip;
+
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ item_size = btrfs_item_size_nr(eb, slot);
+ if (item_size < sizeof(root_item))
+ goto skip;
+
+ trans = NULL;
+ read_extent_buffer(eb, &root_item,
+ btrfs_item_ptr_offset(eb, slot),
+ (int)sizeof(root_item));
+ if (btrfs_root_refs(&root_item) == 0)
+ goto skip;
+ if (!btrfs_is_empty_uuid(root_item.uuid)) {
+ /*
+ * 1 - subvol uuid item
+ * 1 - received_subvol uuid item
+ */
+ trans = btrfs_start_transaction(fs_info->uuid_root, 2);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ break;
+ }
+ ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
+ root_item.uuid,
+ BTRFS_UUID_KEY_SUBVOL,
+ key.objectid);
+ if (ret < 0) {
+ pr_warn("btrfs: uuid_tree_add failed %d\n",
+ ret);
+ btrfs_end_transaction(trans,
+ fs_info->uuid_root);
+ break;
+ }
+ }
+
+ if (!btrfs_is_empty_uuid(root_item.received_uuid)) {
+ if (!trans) {
+ /* 1 - received_subvol uuid item */
+ trans = btrfs_start_transaction(
+ fs_info->uuid_root, 1);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ break;
+ }
+ }
+ ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
+ root_item.received_uuid,
+ BTRFS_UUID_KEY_RECEIVED_SUBVOL,
+ key.objectid);
+ if (ret < 0) {
+ pr_warn("btrfs: uuid_tree_add failed %d\n",
+ ret);
+ btrfs_end_transaction(trans,
+ fs_info->uuid_root);
+ break;
+ }
+ }
+
+ if (trans) {
+ ret = btrfs_end_transaction(trans, fs_info->uuid_root);
+ if (ret)
+ break;
+ }
+
+skip:
+ btrfs_release_path(path);
+ if (key.offset < (u64)-1) {
+ key.offset++;
+ } else if (key.type < BTRFS_ROOT_ITEM_KEY) {
+ key.offset = 0;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ } else if (key.objectid < (u64)-1) {
+ key.offset = 0;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.objectid++;
+ } else {
+ break;
+ }
+ cond_resched();
+ }
+
+out:
+ btrfs_free_path(path);
+ if (ret)
+ pr_warn("btrfs: btrfs_uuid_scan_kthread failed %d\n", ret);
+ up(&fs_info->uuid_tree_rescan_sem);
+ return 0;
+}
+
int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root *uuid_root;
+ struct task_struct *task;
+ int ret;
/*
* 1 - root node
@@ -3453,8 +3589,21 @@ int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
fs_info->uuid_root = uuid_root;
- return btrfs_commit_transaction(trans, tree_root);
+ ret = btrfs_commit_transaction(trans, tree_root);
+ if (ret)
+ return ret;
+
+ down(&fs_info->uuid_tree_rescan_sem);
+ task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
+ if (IS_ERR(task)) {
+ pr_warn("btrfs: failed to start uuid_scan task\n");
+ up(&fs_info->uuid_tree_rescan_sem);
+ return PTR_ERR(task);
+ }
+
+ 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.