ext4: get rid of ppath in ext4_convert_unwritten_extents_endio()

The use of path and ppath is now very confusing, so to make the code more
readable, pass path between functions uniformly, and get rid of ppath.

To get rid of the ppath in ext4_convert_unwritten_extents_endio(), the
following is done here:

 * Free the extents path when an error is encountered.
 * Its caller needs to update ppath if it uses ppath.

No functional changes.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://patch.msgid.link/20240822023545.1994557-20-libaokun@huaweicloud.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/extents.c

@@ -3746,12 +3746,11 @@ static struct ext4_ext_path *ext4_split_convert_extents(handle_t *handle,
 				 allocated);
 }
 
-static int ext4_convert_unwritten_extents_endio(handle_t *handle,
-						struct inode *inode,
-						struct ext4_map_blocks *map,
-						struct ext4_ext_path **ppath)
+static struct ext4_ext_path *
+ext4_convert_unwritten_extents_endio(handle_t *handle, struct inode *inode,
+				     struct ext4_map_blocks *map,
+				     struct ext4_ext_path *path)
 {
-	struct ext4_ext_path *path = *ppath;
 	struct ext4_extent *ex;
 	ext4_lblk_t ee_block;
 	unsigned int ee_len;
@@ -3781,24 +3780,19 @@ static int ext4_convert_unwritten_extents_endio(handle_t *handle,
 #endif
 		path = ext4_split_convert_extents(handle, inode, map, path,
 						EXT4_GET_BLOCKS_CONVERT, NULL);
-		if (IS_ERR(path)) {
-			*ppath = NULL;
-			return PTR_ERR(path);
-		}
+		if (IS_ERR(path))
+			return path;
 
 		path = ext4_find_extent(inode, map->m_lblk, path, 0);
-		if (IS_ERR(path)) {
-			*ppath = NULL;
-			return PTR_ERR(path);
-		}
-		*ppath = path;
+		if (IS_ERR(path))
+			return path;
 		depth = ext_depth(inode);
 		ex = path[depth].p_ext;
 	}
 
 	err = ext4_ext_get_access(handle, inode, path + depth);
 	if (err)
-		goto out;
+		goto errout;
 	/* first mark the extent as initialized */
 	ext4_ext_mark_initialized(ex);
 
@@ -3809,9 +3803,15 @@ static int ext4_convert_unwritten_extents_endio(handle_t *handle,
 
 	/* Mark modified extent as dirty */
 	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
-out:
+	if (err)
+		goto errout;
+
 	ext4_ext_show_leaf(inode, path);
-	return err;
+	return path;
+
+errout:
+	ext4_free_ext_path(path);
+	return ERR_PTR(err);
 }
 
 static int
@@ -3939,10 +3939,13 @@ ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
 	}
 	/* IO end_io complete, convert the filled extent to written */
 	if (flags & EXT4_GET_BLOCKS_CONVERT) {
-		err = ext4_convert_unwritten_extents_endio(handle, inode, map,
-							   ppath);
-		if (err < 0)
+		*ppath = ext4_convert_unwritten_extents_endio(handle, inode,
+							      map, *ppath);
+		if (IS_ERR(*ppath)) {
+			err = PTR_ERR(*ppath);
+			*ppath = NULL;
 			goto out2;
+		}
 		ext4_update_inode_fsync_trans(handle, inode, 1);
 		goto map_out;
 	}