btrfs: use a single variable to track return value for log_dir_items()

We currently use 'ret' and 'err' to track the return value for
log_dir_items(), which is confusing and likely the cause for previous
bugs where log_dir_items() did not return an error when it should, fixed
in previous patches.

So change this and use only a single variable, 'ret', to track the return
value. This is simpler and makes it similar to most of the existing code.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/tree-log.c

@@ -3793,7 +3793,6 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
 	struct btrfs_key min_key;
 	struct btrfs_root *root = inode->root;
 	struct btrfs_root *log = root->log_root;
-	int err = 0;
 	int ret;
 	u64 last_old_dentry_offset = min_offset - 1;
 	u64 last_offset = (u64)-1;
@@ -3834,8 +3833,8 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
 					      path->slots[0]);
 			if (tmp.type == BTRFS_DIR_INDEX_KEY)
 				last_old_dentry_offset = tmp.offset;
-		} else if (ret < 0) {
-			err = ret;
+		} else if (ret > 0) {
+			ret = 0;
 		}
 
 		goto done;
@@ -3858,7 +3857,6 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
 		if (tmp.type == BTRFS_DIR_INDEX_KEY)
 			last_old_dentry_offset = tmp.offset;
 	} else if (ret < 0) {
-		err = ret;
 		goto done;
 	}
 
@@ -3880,12 +3878,15 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
 	 */
 search:
 	ret = btrfs_search_slot(NULL, root, &min_key, path, 0, 0);
-	if (ret > 0)
+	if (ret > 0) {
 		ret = btrfs_next_item(root, path);
+		if (ret > 0) {
+			/* There are no more keys in the inode's root. */
+			ret = 0;
+			goto done;
+		}
+	}
 	if (ret < 0)
-		err = ret;
-	/* If ret is 1, there are no more keys in the inode's root. */
-	if (ret != 0)
 		goto done;
 
 	/*
@@ -3896,8 +3897,8 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
 		ret = process_dir_items_leaf(trans, inode, path, dst_path, ctx,
 					     &last_old_dentry_offset);
 		if (ret != 0) {
-			if (ret < 0)
-				err = ret;
+			if (ret > 0)
+				ret = 0;
 			goto done;
 		}
 		path->slots[0] = btrfs_header_nritems(path->nodes[0]);
@@ -3908,10 +3909,10 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
 		 */
 		ret = btrfs_next_leaf(root, path);
 		if (ret) {
-			if (ret == 1)
+			if (ret == 1) {
 				last_offset = (u64)-1;
-			else
-				err = ret;
+				ret = 0;
+			}
 			goto done;
 		}
 		btrfs_item_key_to_cpu(path->nodes[0], &min_key, path->slots[0]);
@@ -3942,7 +3943,7 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
 	btrfs_release_path(path);
 	btrfs_release_path(dst_path);
 
-	if (err == 0) {
+	if (ret == 0) {
 		*last_offset_ret = last_offset;
 		/*
 		 * In case the leaf was changed in the current transaction but
@@ -3953,15 +3954,13 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
 		 * a range, last_old_dentry_offset is == to last_offset.
 		 */
 		ASSERT(last_old_dentry_offset <= last_offset);
-		if (last_old_dentry_offset < last_offset) {
+		if (last_old_dentry_offset < last_offset)
 			ret = insert_dir_log_key(trans, log, path, ino,
 						 last_old_dentry_offset + 1,
 						 last_offset);
-			if (ret)
-				err = ret;
-		}
 	}
-	return err;
+
+	return ret;
 }
 
 /*