btrfs: keep orphans for subvolume deletion

Since we have the free space caches, btrfs_orphan_cleanup also runs for
the tree_root. Unfortunately this also cleans up the orphans used to mark
subvol deletions in progress.

Currently if a subvol deletion gets interrupted twice by umount/mount, the
deletion will not be continued and the space permanently lost, though it
would be possible to write a tool to recover those lost subvol deletions.
This patch checks if the orphan belongs to a subvol (dead root) and skips
the deletion.

Signed-off-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Arne Jansen 2011-12-14 20:12:02 -05:00 коммит произвёл Chris Mason
Родитель 39fb26c398
Коммит f8e9e0b07b
1 изменённых файлов: 32 добавлений и 0 удалений

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@ -2158,6 +2158,38 @@ int btrfs_orphan_cleanup(struct btrfs_root *root)
if (ret && ret != -ESTALE)
goto out;
if (ret == -ESTALE && root == root->fs_info->tree_root) {
struct btrfs_root *dead_root;
struct btrfs_fs_info *fs_info = root->fs_info;
int is_dead_root = 0;
/*
* this is an orphan in the tree root. Currently these
* could come from 2 sources:
* a) a snapshot deletion in progress
* b) a free space cache inode
* We need to distinguish those two, as the snapshot
* orphan must not get deleted.
* find_dead_roots already ran before us, so if this
* is a snapshot deletion, we should find the root
* in the dead_roots list
*/
spin_lock(&fs_info->trans_lock);
list_for_each_entry(dead_root, &fs_info->dead_roots,
root_list) {
if (dead_root->root_key.objectid ==
found_key.objectid) {
is_dead_root = 1;
break;
}
}
spin_unlock(&fs_info->trans_lock);
if (is_dead_root) {
/* prevent this orphan from being found again */
key.offset = found_key.objectid - 1;
continue;
}
}
/*
* Inode is already gone but the orphan item is still there,
* kill the orphan item.