On 2020/06/12 17:34, Sungjong Seo wrote:
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...@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?
I also think ‘do nothing when wait is 0’ as you say, but I'm still not sure.
Some other Filesystems do nothing with nowait and just return.
However, a few Filesystems always perform sync.
sync_blockdev() waits for completion, so it may be inappropriate to call with
nowait. (But it was called in the original code)
I'm still not sure, so I excluded it in this patch.
Is it okay to include it?
+ 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
BR
---
Tetsuhiro Kohada <kohada...@gmail.com>
