btrfs: deal with errors when checking if a dir entry exists during log replay

Currently inode_in_dir() ignores errors returned from
btrfs_lookup_dir_index_item() and from btrfs_lookup_dir_item(), treating
any errors as if the directory entry does not exists in the fs/subvolume
tree, which is obviously not correct, as we can get errors such as -EIO
when reading extent buffers while searching the fs/subvolume's tree.

Fix that by making inode_in_dir() return the errors and making its only
caller, add_inode_ref(), deal with returned errors as well.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index f7efc26..491d4ba 100644 (file)
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -939,9 +939,11 @@ out:
 }
 
 /*
- * helper function to see if a given name and sequence number found
- * in an inode back reference are already in a directory and correctly
- * point to this inode
+ * See if a given name and sequence number found in an inode back reference are
+ * already in a directory and correctly point to this inode.
+ *
+ * Returns: < 0 on error, 0 if the directory entry does not exists and 1 if it
+ * exists.
  */
 static noinline int inode_in_dir(struct btrfs_root *root,
                                 struct btrfs_path *path,
@@ -950,29 +952,35 @@ static noinline int inode_in_dir(struct btrfs_root *root,
 {
        struct btrfs_dir_item *di;
        struct btrfs_key location;
-       int match = 0;
+       int ret = 0;
 
        di = btrfs_lookup_dir_index_item(NULL, root, path, dirid,
                                         index, name, name_len, 0);
-       if (di && !IS_ERR(di)) {
+       if (IS_ERR(di)) {
+               if (PTR_ERR(di) != -ENOENT)
+                       ret = PTR_ERR(di);
+               goto out;
+       } else if (di) {
                btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
                if (location.objectid != objectid)
                        goto out;
-       } else
+       } else {
                goto out;
-       btrfs_release_path(path);
+       }
 
+       btrfs_release_path(path);
        di = btrfs_lookup_dir_item(NULL, root, path, dirid, name, name_len, 0);
-       if (di && !IS_ERR(di)) {
-               btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
-               if (location.objectid != objectid)
-                       goto out;
-       } else
+       if (IS_ERR(di)) {
+               ret = PTR_ERR(di);
                goto out;
-       match = 1;
+       } else if (di) {
+               btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
+               if (location.objectid == objectid)
+                       ret = 1;
+       }
 out:
        btrfs_release_path(path);
-       return match;
+       return ret;
 }
 
 /*
@@ -1517,10 +1525,12 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
                if (ret)
                        goto out;
 
-               /* if we already have a perfect match, we're done */
-               if (!inode_in_dir(root, path, btrfs_ino(BTRFS_I(dir)),
-                                       btrfs_ino(BTRFS_I(inode)), ref_index,
-                                       name, namelen)) {
+               ret = inode_in_dir(root, path, btrfs_ino(BTRFS_I(dir)),
+                                  btrfs_ino(BTRFS_I(inode)), ref_index,
+                                  name, namelen);
+               if (ret < 0) {
+                       goto out;
+               } else if (ret == 0) {
                        /*
                         * look for a conflicting back reference in the
                         * metadata. if we find one we have to unlink that name
@@ -1580,6 +1590,7 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
                        if (ret)
                                goto out;
                }
+               /* Else, ret == 1, we already have a perfect match, we're done. */
 
                ref_ptr = (unsigned long)(ref_ptr + ref_struct_size) + namelen;
                kfree(name);