Btrfs: forced readonly when btrfs_drop_snapshot() fails

The filesystem turns readonly instead of returning the error to the
caller when detected error in btrfs_drop_snapshot().
and, because the caller doesn't check the error, the function type is
changed to 'void'.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

2 files changed, 16 insertions, 10 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index a6263bdab818..884293642a6c 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2367,8 +2367,8 @@ static inline int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path);
 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf);
-int btrfs_drop_snapshot(struct btrfs_root *root,
-                        struct btrfs_block_rsv *block_rsv, int update_ref);
+void btrfs_drop_snapshot(struct btrfs_root *root,
+                         struct btrfs_block_rsv *block_rsv, int update_ref);
 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root,
                         struct extent_buffer *node,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a3e71b59f66e..80d6148f60ac 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6277,8 +6277,8 @@ static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
  * also make sure backrefs for the shared block and all lower level
  * blocks are properly updated.
  */
-int btrfs_drop_snapshot(struct btrfs_root *root,
-                        struct btrfs_block_rsv *block_rsv, int update_ref)
+void btrfs_drop_snapshot(struct btrfs_root *root,
+                         struct btrfs_block_rsv *block_rsv, int update_ref)
 {
         struct btrfs_path *path;
         struct btrfs_trans_handle *trans;
@@ -6291,13 +6291,16 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
         int level;
 
         path = btrfs_alloc_path();
-        if (!path)
-                return -ENOMEM;
+        if (!path) {
+                err = -ENOMEM;
+                goto out;
+        }
 
         wc = kzalloc(sizeof(*wc), GFP_NOFS);
         if (!wc) {
                 btrfs_free_path(path);
-                return -ENOMEM;
+                err = -ENOMEM;
+                goto out;
         }
 
         trans = btrfs_start_transaction(tree_root, 0);
@@ -6326,7 +6329,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
                 path->lowest_level = 0;
                 if (ret < 0) {
                         err = ret;
-                        goto out;
+                        goto out_free;
                 }
                 WARN_ON(ret > 0);
 
@@ -6433,11 +6436,14 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
                 free_extent_buffer(root->commit_root);
                 kfree(root);
         }
-out:
+out_free:
         btrfs_end_transaction_throttle(trans, tree_root);
         kfree(wc);
         btrfs_free_path(path);
-        return err;
+out:
+        if (err)
+                btrfs_std_error(root->fs_info, err);
+        return;
 }
 
 /*