f2fs: fix incorrect return statement in the function f2fs_ioc_release_volatile_write

This fixes the incorrect return statement at the end of the function
f2fs_ioc_release_volatile_write's body for returning zero as this is
incorrect due to the function call before this return statement to
the function punch_hole being able to fail and we should return this
function's return fail directly in order to signal to callers of the
function f2fs_ioc_release_volatile if a failure arises with this call
to punch_hole fails.

Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/file.c

@@ -1437,8 +1437,7 @@ static int f2fs_ioc_release_volatile_write(struct file *filp)
 	if (!f2fs_is_first_block_written(inode))
 		return truncate_partial_data_page(inode, 0, true);
 
-	punch_hole(inode, 0, F2FS_BLKSIZE);
-	return 0;
+	return punch_hole(inode, 0, F2FS_BLKSIZE);
 }
 
 static int f2fs_ioc_abort_volatile_write(struct file *filp)