Messages in this thread | | | From | "" <> | Subject | RE: [PATCH] exfat: do not clear VolumeDirty in writeback | Date | Mon, 28 Feb 2022 10:51:54 +0000 |
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Hi, Kohada.Tetsuhiro.
Thank for your comments.
>> And VolumeDirty will be set again when updating the parent directory. >> It means that BootSector will be written twice in each writeback, that will shorten the life of the device. > > I have the same concern. > From a lifespan point of view, we should probably clear dirty with just sync_fs().
If it is acceptable for VolumeDirty to remain dirty after all updates are complete, I think it is a good idea. (PS: The original logic is to clear VolumeDirty after BitMap, FAT and directory entries are updated.)
>> sync_blockdev(sb->s_bdev); >> - if (exfat_clear_volume_dirty(sb)) >> + if (__exfat_clear_volume_dirty(sb)) > > If SB_SYNCHRONOUS or SB_DIRSYNC is not present, isn't dirty cleared?
With this patch, exfat_clear_volume_dirty() will not clear VolumeDirty if SB_SYNCHRONOUS or SB_DIRSYNC is not present, and __exfat_clear_volume_dirty() will clear VolumeDirty unconditionally.
>> +int exfat_clear_volume_dirty(struct super_block *sb) { >> + if (sb->s_flags & (SB_SYNCHRONOUS | SB_DIRSYNC)) >> + return __exfat_clear_volume_dirty(sb); > > Even when only one of SB or DIR is synced, dirty will be cleared. > Isn't it necessary to have both SB_SYNCHRONOUS and SB_DIRSYNC?
VolumeDirty will be cleared if one of SB_SYNCHRONOUS and SB_DIRSYNC is set. The condition of (sb->s_flags & (SB_SYNCHRONOUS | SB_DIRSYNC)) is exactly that.
> And, I think it would be better to use IS_SYNC or IS_DIRSYNC macro here.
If use IS_SYNC or IS_DIRSYNC, we should pass `inode` as an argument, it will be a big change for code. And if open a file with O_SYNC, IS_DIRSYNC and IS_SYNC will be true, VolumeDirty will be cleared. So I think it is not necessary to use IS_DIRSYNC and IS_SYNC.
Best Regards, Yuezhang,Mo
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