Btrfs: unify error handling of btrfs_lookup_dir_item

Unify the error handling of directory item lookups using IS_ERR_OR_NULL.
No functional changes.

Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -3907,12 +3907,8 @@ static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
 	path->leave_spinning = 1;
 	di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
 				    name, name_len, -1);
-	if (IS_ERR(di)) {
-		ret = PTR_ERR(di);
-		goto err;
-	}
-	if (!di) {
-		ret = -ENOENT;
+	if (IS_ERR_OR_NULL(di)) {
+		ret = di ? PTR_ERR(di) : -ENOENT;
 		goto err;
 	}
 	leaf = path->nodes[0];
@@ -4072,10 +4068,7 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 	di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
 				   name, name_len, -1);
 	if (IS_ERR_OR_NULL(di)) {
-		if (!di)
-			ret = -ENOENT;
-		else
-			ret = PTR_ERR(di);
+		ret = di ? PTR_ERR(di) : -ENOENT;
 		goto out;
 	}
 
@@ -5467,12 +5460,8 @@ static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
 
 	di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(BTRFS_I(dir)),
 			name, namelen, 0);
-	if (!di) {
-		ret = -ENOENT;
-		goto out;
-	}
-	if (IS_ERR(di)) {
-		ret = PTR_ERR(di);
+	if (IS_ERR_OR_NULL(di)) {
+		ret = di ? PTR_ERR(di) : -ENOENT;
 		goto out;
 	}
 

fs/btrfs/send.c

@@ -1693,12 +1693,8 @@ static int lookup_dir_item_inode(struct btrfs_root *root,
 
 	di = btrfs_lookup_dir_item(NULL, root, path,
 			dir, name, name_len, 0);
-	if (!di) {
-		ret = -ENOENT;
-		goto out;
-	}
-	if (IS_ERR(di)) {
-		ret = PTR_ERR(di);
+	if (IS_ERR_OR_NULL(di)) {
+		ret = di ? PTR_ERR(di) : -ENOENT;
 		goto out;
 	}
 	btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);