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Commit f8e9e0b0 authored by Arne Jansen's avatar Arne Jansen Committed by Chris Mason
Browse files

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: default avatarArne Jansen <sensille@gmx.net>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 39fb26c3

fs/btrfs/inode.c

+32 −0
Original line number Diff line number Diff line
@@ -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.