From: "Sungjong Seo" <sj1557.seo@samsung.com>
To: "'Tetsuhiro Kohada'" <kohada.t2@gmail.com>
Cc: <kohada.tetsuhiro@dc.mitsubishielectric.co.jp>,
<mori.takahiro@ab.mitsubishielectric.co.jp>,
<motai.hirotaka@aj.mitsubishielectric.co.jp>,
"'Namjae Jeon'" <namjae.jeon@samsung.com>,
<linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] exfat: remove EXFAT_SB_DIRTY flag
Date: Fri, 12 Jun 2020 17:34:46 +0900 [thread overview]
Message-ID: <219a01d64094$5418d7a0$fc4a86e0$@samsung.com> (raw)
In-Reply-To: <20200612012834.13503-1-kohada.t2@gmail.com>
> 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.
>
> Remove the EXFAT_SB_DIRTY check to ensure synchronization.
> And, remove the code related to the flag.
>
> Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
> ---
> fs/exfat/balloc.c | 4 ++--
> fs/exfat/dir.c | 16 ++++++++--------
> fs/exfat/exfat_fs.h | 5 +----
> fs/exfat/fatent.c | 7 ++-----
> fs/exfat/misc.c | 3 +--
> fs/exfat/namei.c | 12 ++++++------
> fs/exfat/super.c | 11 +++--------
> 7 files changed, 23 insertions(+), 35 deletions(-)
>
[snip]
>
> @@ -62,11 +59,9 @@ static int exfat_sync_fs(struct super_block *sb, int
> wait)
>
> /* If there are some dirty buffers in the bdev inode */
> mutex_lock(&sbi->s_lock);
> - if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) {
> - sync_blockdev(sb->s_bdev);
> - if (exfat_set_vol_flags(sb, VOL_CLEAN))
> - err = -EIO;
> - }
I looked through most codes related to EXFAT_SB_DIRTY and VOL_DIRTY.
And your approach looks good because all of them seem to be protected by
s_lock.
BTW, as you know, sync_filesystem() calls sync_fs() with 'nowait' first,
and then calls it again with 'wait' twice. No need to sync with lock twice.
If so, isn't it okay to do nothing when wait is 0?
> + sync_blockdev(sb->s_bdev);
> + if (exfat_set_vol_flags(sb, VOL_CLEAN))
> + err = -EIO;
> mutex_unlock(&sbi->s_lock);
> return err;
> }
> --
> 2.25.1
next prev parent reply other threads:[~2020-06-12 8:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20200612012902epcas1p4194d6fa3b3f7c46a8becb9bb6ce23d56@epcas1p4.samsung.com>
2020-06-12 1:28 ` [PATCH] exfat: remove EXFAT_SB_DIRTY flag Tetsuhiro Kohada
2020-06-12 8:34 ` Sungjong Seo [this message]
2020-06-12 10:22 ` Tetsuhiro Kohada
2020-06-15 2:59 ` Sungjong Seo
2020-06-15 8:31 ` Kohada.Tetsuhiro
2020-06-12 8:48 Markus Elfring
2020-06-12 10:01 ` Greg KH
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