RE: [PATCH v3] exfat: remove EXFAT_SB_DIRTY flag

[Namjae Jeon]

> remove EXFAT_SB_DIRTY flag and related codes.
> 
> This flag is set/reset in exfat_put_super()/exfat_sync_fs() to avoid sync_blockdev().
> However ...
> - exfat_put_super():
> Before calling this, the VFS has already called sync_filesystem(), so sync is never performed here.
> - exfat_sync_fs():
> After calling this, the VFS calls sync_blockdev(), so, it is meaningless to check EXFAT_SB_DIRTY or to
> bypass sync_blockdev() here.
> Not only that, but in some cases can't clear VOL_DIRTY.
> ex:
> VOL_DIRTY is set when rmdir starts, but when non-empty-dir is detected, return error without setting
> EXFAT_SB_DIRTY.
> If performe 'sync' in this state, VOL_DIRTY will not be cleared.
There is still a problem if system reboot or device is unplugged when sync is not called yet.
I will remove this mention in the patch.