Merge branch 'no-rebase-mnt_ns_tree_remove'

Bring in the fix for removing a mount namespace from the mount namespace
rbtree and list.

Signed-off-by: Christian Brauner <brauner@kernel.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index e58151933844..7256f6748c8f 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -602,6 +602,25 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
 	if (btrfs_root_id(root) == objectid) {
 		u64 commit_root_gen;
 
+		/*
+		 * Relocation will wait for cleaner thread, and any half-dropped
+		 * subvolume will be fully cleaned up at mount time.
+		 * So here we shouldn't hit a subvolume with non-zero drop_progress.
+		 *
+		 * If this isn't the case, error out since it can make us attempt to
+		 * drop references for extents that were already dropped before.
+		 */
+		if (unlikely(btrfs_disk_key_objectid(&root->root_item.drop_progress))) {
+			struct btrfs_key cpu_key;
+
+			btrfs_disk_key_to_cpu(&cpu_key, &root->root_item.drop_progress);
+			btrfs_err(fs_info,
+	"cannot relocate partially dropped subvolume %llu, drop progress key (%llu %u %llu)",
+				  objectid, cpu_key.objectid, cpu_key.type, cpu_key.offset);
+			ret = -EUCLEAN;
+			goto fail;
+		}
+
 		/* called by btrfs_init_reloc_root */
 		ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
 				      BTRFS_TREE_RELOC_OBJECTID);