btrfs: keep orphans for subvolume deletion (f8e9e0b0) · Commits · 戴 / test

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>

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.

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