fat: Fix statfs->f_namelen

pathconf(, _PC_NAME_MAX) is too small for long Unicode filename on fat.

255 as max filename size on fat is Unicode UTF-16 characters.
it's not byte size.

https://bugzilla.kernel.org/show_bug.cgi?id=16469

To fix it, this returns "len * NLS_MAX_CHARSET_SIZE" instead.

Reported-by: Takumi Asaki <takumi.asaki@nokia.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 7a6c819893f2..cb8d8391ac0b 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -581,7 +581,8 @@ static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
         buf->f_bavail = sbi->free_clusters;
         buf->f_fsid.val[0] = (u32)id;
         buf->f_fsid.val[1] = (u32)(id >> 32);
-        buf->f_namelen = sbi->options.isvfat ? FAT_LFN_LEN : 12;
+        buf->f_namelen =
+                (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
 
         return 0;
 }