btrfs: introduce btrfs_lookup_match_dir

btrfs_search_slot is called in multiple places in dir-item.c to search
for a dir entry, and then calling btrfs_match_dir_name to return a
btrfs_dir_item.

In order to reduce the number of callers of btrfs_search_slot, create a
common function that looks for the dir key, and if found call
btrfs_match_dir_item_name.
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/dir-item.c

@@ -170,6 +170,25 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, const char *name,
 	return 0;
 }
 
+static struct btrfs_dir_item *btrfs_lookup_match_dir(
+			struct btrfs_trans_handle *trans,
+			struct btrfs_root *root, struct btrfs_path *path,
+			struct btrfs_key *key, const char *name,
+			int name_len, int mod)
+{
+	const int ins_len = (mod < 0 ? -1 : 0);
+	const int cow = (mod != 0);
+	int ret;
+
+	ret = btrfs_search_slot(trans, root, key, path, ins_len, cow);
+	if (ret < 0)
+		return ERR_PTR(ret);
+	if (ret > 0)
+		return ERR_PTR(-ENOENT);
+
+	return btrfs_match_dir_item_name(root->fs_info, path, name, name_len);
+}
+
 /*
  * lookup a directory item based on name.  'dir' is the objectid
  * we're searching in, and 'mod' tells us if you plan on deleting the
@@ -181,23 +200,18 @@ struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 					     const char *name, int name_len,
 					     int mod)
 {
-	int ret;
 	struct btrfs_key key;
-	int ins_len = mod < 0 ? -1 : 0;
-	int cow = mod != 0;
+	struct btrfs_dir_item *di;
 
 	key.objectid = dir;
 	key.type = BTRFS_DIR_ITEM_KEY;
-
 	key.offset = btrfs_name_hash(name, name_len);
 
-	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
-	if (ret < 0)
-		return ERR_PTR(ret);
-	if (ret > 0)
+	di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
+	if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
 		return NULL;
 
-	return btrfs_match_dir_item_name(root->fs_info, path, name, name_len);
+	return di;
 }
 
 int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
@@ -211,7 +225,6 @@ int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
 	int slot;
 	struct btrfs_path *path;
 
-
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
@@ -220,20 +233,20 @@ int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
 	key.type = BTRFS_DIR_ITEM_KEY;
 	key.offset = btrfs_name_hash(name, name_len);
 
-	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-
-	/* return back any errors */
-	if (ret < 0)
-		goto out;
+	di = btrfs_lookup_match_dir(NULL, root, path, &key, name, name_len, 0);
+	if (IS_ERR(di)) {
+		ret = PTR_ERR(di);
+		/* Nothing found, we're safe */
+		if (ret == -ENOENT) {
+			ret = 0;
+			goto out;
+		}
 
-	/* nothing found, we're safe */
-	if (ret > 0) {
-		ret = 0;
-		goto out;
+		if (ret < 0)
+			goto out;
 	}
 
 	/* we found an item, look for our name in the item */
-	di = btrfs_match_dir_item_name(root->fs_info, path, name, name_len);
 	if (di) {
 		/* our exact name was found */
 		ret = -EEXIST;
@@ -274,21 +287,13 @@ btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 			    u64 objectid, const char *name, int name_len,
 			    int mod)
 {
-	int ret;
 	struct btrfs_key key;
-	int ins_len = mod < 0 ? -1 : 0;
-	int cow = mod != 0;
 
 	key.objectid = dir;
 	key.type = BTRFS_DIR_INDEX_KEY;
 	key.offset = objectid;
 
-	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
-	if (ret < 0)
-		return ERR_PTR(ret);
-	if (ret > 0)
-		return ERR_PTR(-ENOENT);
-	return btrfs_match_dir_item_name(root->fs_info, path, name, name_len);
+	return btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
 }
 
 struct btrfs_dir_item *
@@ -345,21 +350,18 @@ struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
 					  const char *name, u16 name_len,
 					  int mod)
 {
-	int ret;
 	struct btrfs_key key;
-	int ins_len = mod < 0 ? -1 : 0;
-	int cow = mod != 0;
+	struct btrfs_dir_item *di;
 
 	key.objectid = dir;
 	key.type = BTRFS_XATTR_ITEM_KEY;
 	key.offset = btrfs_name_hash(name, name_len);
-	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
-	if (ret < 0)
-		return ERR_PTR(ret);
-	if (ret > 0)
+
+	di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
+	if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
 		return NULL;
 
-	return btrfs_match_dir_item_name(root->fs_info, path, name, name_len);
+	return di;
 }
 
 /*