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>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f1c4bce..4a31493 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2158,6 +2158,38 @@
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.