linux-kernel - Re: [f2fs-dev] [PATCH] f2fs: fix quota info to adjust recovered data

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Message-ID: <20180912195406.GB8356@jaegeuk-macbookpro.roam.corp.google.com>
Date:   Wed, 12 Sep 2018 12:54:06 -0700
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Chao Yu <yuchao0@...wei.com>
Cc:     Chao Yu <chao@...nel.org>, linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix quota info to adjust recovered data

On 09/12, Chao Yu wrote:
> On 2018/9/12 9:40, Chao Yu wrote:
> > On 2018/9/12 9:25, Jaegeuk Kim wrote:
> >> On 09/12, Chao Yu wrote:
> >>> On 2018/9/12 8:27, Jaegeuk Kim wrote:
> >>>> On 09/11, Jaegeuk Kim wrote:
> >>>>> On 09/12, Chao Yu wrote:
> >>>>>> On 2018/9/12 4:15, Jaegeuk Kim wrote:
> >>>>>>> fsck.f2fs is able to recover the quota structure, since roll-forward recovery
> >>>>>>> can recover it based on previous user information.
> >>>>>>
> >>>>>> I didn't get it, both fsck and kernel recover quota file based all inodes'
> >>>>>> uid/gid/prjid, if {x}id didn't change, wouldn't those two recovery result be the
> >>>>>> same?
> >>>>>
> >>>>> I thought that, but had to add this, since I was encountering quota errors right
> >>>>> after getting some files recovered. And, I thought it'd make it more safe to do
> >>>>> fsck after roll-forward recovery.
> >>>>>
> >>>>> Anyway, let me test again without this patch for a while.
> >>>>
> >>>> Hmm, I just got a fsck failure right after some files recovered.
> >>>
> >>> To make sure, do you test with "f2fs: guarantee journalled quota data by
> >>> checkpoint"? if not, I think there is no guarantee that f2fs can recover
> >>> quote info into correct quote file, because, in last checkpoint, quota file
> >>> may was corrupted/inconsistent. Right?
> > 
> > Oh, I forget to mention that, I add a patch to fsck to let it noticing
> > CP_QUOTA_NEED_FSCK_FLAG flag, and by default, fsck will fix corrupted quote
> > file if the flag is set, but w/o this flag, quota file is still corrupted
> > detected by fsck, I guess there is bug in v8.
> 
> In v8, there are two cases we didn't guarantee quota file's consistence:
> 1. flush time in block_operation exceed a threshold.
> 2. dquot subsystem error occurs.
> 
> For above case, fsck should repair the quota file by default.

Okay, I got another failure and it seems CP_QUOTA_NEED_FSCK_FLAG was not set
during the recovery. So, we have something missing in the recovery in terms
of quota updates.

> 
> > 
> > Can you add that in fsck too? so we can separate real kernel bug and quota
> > file corruption due to dquot subsystem error caused like below case:
> > 
> > +static int f2fs_dquot_acquire(struct dquot *dquot)
> > +{
> > +	int ret;
> > +
> > +	ret = dquot_acquire(dquot);
> > +	if (ret == -ENOSPC || ret == -EIO)
> > +		set_sbi_flag(F2FS_SB(dquot->dq_sb), SBI_QUOTA_NEED_REPAIR);
> > +	return ret;
> > +}
> > 
> >>
> >> I hit the failure with v8. And, the test scenario is 1) enable fault injection
> >> 2) run fsstress, 3) call shutdowon, 4) kill fsstress, 5) unmount, 6) fsck, 7)
> >> mount, 8) fsck, 9) go 1).
> 
> 8) fsck is do fscking in a mounted image?

Missing unmount before 8). :P

> 
> Thanks,
> 
> >>
> >> So, I'm hitting failure in 8) fsck. I expect 6) fsck should fix any corruption
> >> and 7) recovered some files on clean checkpoint.
> > 
> > I see, I can add this case too, does this exist in your xfstest tree in github?
> > 
> > Thanks,
> > 
> >>
> >> Thanks,
> >>
> >>>
> >>> Thanks,
> >>>
> >>>>
> >>>>>
> >>>>> Thanks,
> >>>>>
> >>>>>
> >>>>>>
> >>>>>> Thanks,
> >>>>>>
> >>>>>>>
> >>>>>>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> >>>>>>> ---
> >>>>>>>  fs/f2fs/recovery.c | 3 +++
> >>>>>>>  1 file changed, 3 insertions(+)
> >>>>>>>
> >>>>>>> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
> >>>>>>> index 95511ed11a22..1fde86a2107e 100644
> >>>>>>> --- a/fs/f2fs/recovery.c
> >>>>>>> +++ b/fs/f2fs/recovery.c
> >>>>>>> @@ -675,6 +675,9 @@ int f2fs_recover_fsync_data(struct f2fs_sb_info *sbi, bool check_only)
> >>>>>>>  
> >>>>>>>  	need_writecp = true;
> >>>>>>>  
> >>>>>>> +	/* quota is not fully updated due to the lack of user information. */
> >>>>>>> +	set_sbi_flag(sbi, SBI_NEED_FSCK);
> >>>>>>> +
> >>>>>>>  	/* step #2: recover data */
> >>>>>>>  	err = recover_data(sbi, &inode_list, &dir_list);
> >>>>>>>  	if (!err)
> >>>>>>>
> >>>>>
> >>>>>
> >>>>> _______________________________________________
> >>>>> Linux-f2fs-devel mailing list
> >>>>> Linux-f2fs-devel@...ts.sourceforge.net
> >>>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> >>>>
> >>>> .
> >>>>
> >>
> >> .
> >>
> > 
> > 
> > .
> >