f2fs: avoid to create an empty string as the extension_list

When creating a file, we need to set the temperature based on
extension_list. If the empty string is a valid extension_list,
the is_extension_exist will always returns true,
which affects the separation of hot and cold.

Signed-off-by: Wang Xiaojun <wangxiaojun11@huawei.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 15fe30d..b172562 100644 (file)
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -351,7 +351,7 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
                        set = false;
                }
 
-               if (strlen(name) >= F2FS_EXTENSION_LEN)
+               if (!strlen(name) || strlen(name) >= F2FS_EXTENSION_LEN)
                        return -EINVAL;
 
                down_write(&sbi->sb_lock);