linux-kernel - RE: [PATCH] exfat: do not clear VolumeDirty in writeback

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Date:   Tue, 8 Mar 2022 10:55:28 +0000
From:   "Yuezhang.Mo@...y.com" <Yuezhang.Mo@...y.com>
To:     Namjae Jeon <linkinjeon@...nel.org>
CC:     "sj1557.seo@...sung.com" <sj1557.seo@...sung.com>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Andy.Wu@...y.com" <Andy.Wu@...y.com>,
        "Wataru.Aoyama@...y.com" <Wataru.Aoyama@...y.com>,
        "Kohada.Tetsuhiro@...MitsubishiElectric.co.jp" 
        <Kohada.Tetsuhiro@...MitsubishiElectric.co.jp>
Subject: RE: [PATCH] exfat: do not clear VolumeDirty in writeback

Hi Namjae Jeon,

> > +int exfat_clear_volume_dirty(struct super_block *sb) {
> > +	if (sb->s_flags & (SB_SYNCHRONOUS | SB_DIRSYNC))
> How about moving exfat_clear_volume_dirty() to IS_DIRSYNC() check in each
> operations instead of this check?

I found that VolumeDirty keeps VOL_DIRTY until sync or umount regardless of sync or dirsync enabled, 
because there is no paired call to exfat_set_volume_dirty()/exfat_clear_volume_dirty() in __exfat_write_inode().

If exfat_set_volume_dirty()/exfat_clear_volume_dirty() is called in pairs in __exfat_write_inode(),
it will cause frequent writing of bootsector.

So, how about removing exfat_clear_volume_dirty() from each operations, except in exfat_sync_fs()?

Best Regards,
Yuezhang Mo