[PATCH v2] btrfs: Fix passing 0 to ERR_PTR in btrfs_search_dir_index_item()

[Yue Haibing]

ret may be zero in btrfs_search_dir_index_item() and should not passed
to ERR_PTR(). Now btrfs_unlink_subvol() is the only caller to this,
reconstructed it to check ERR_PTR(-ENOENT) while ret >= 0, this fix
smatch warnings:

fs/btrfs/dir-item.c:353
 btrfs_search_dir_index_item() warn: passing zero to 'ERR_PTR'

Fixes: 9dcbe16fccbb ("btrfs: use btrfs_for_each_slot in btrfs_search_dir_index_item")
Signed-off-by: Yue Haibing <yuehaibing@xxxxxxxxxx>
---
v2: return ERR_PTR(-ENOENT) while ret >= 0
---
 fs/btrfs/dir-item.c | 4 ++--
 fs/btrfs/inode.c    | 7 ++-----
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index d3093eba54a5..1ea5d8fcfbf7 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -345,8 +345,8 @@ btrfs_search_dir_index_item(struct btrfs_root *root, struct btrfs_path *path,
 			return di;
 	}
 	/* Adjust return code if the key was not found in the next leaf. */
-	if (ret > 0)
-		ret = 0;
+	if (ret >= 0)
+		ret = -ENOENT;
 
 	return ERR_PTR(ret);
 }
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index acb206d5da3b..7569c8b27f9f 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4373,11 +4373,8 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 	 */
 	if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID) {
 		di = btrfs_search_dir_index_item(root, path, dir_ino, &fname.disk_name);
-		if (IS_ERR_OR_NULL(di)) {
-			if (!di)
-				ret = -ENOENT;
-			else
-				ret = PTR_ERR(di);
+		if (IS_ERR(di)) {
+			ret = PTR_ERR(di);
 			btrfs_abort_transaction(trans, ret);
 			goto out;
 		}
-- 
2.34.1