Re: [PATCH] xfs/097: Remove wrong broken assignment operation

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On Tue, Oct 22, 2019 at 09:49:48AM +0800, Yang Xu wrote:
> 
> 
> on 2019/10/21 23:50, Darrick J. Wong wrote:
> > On Mon, Oct 21, 2019 at 08:09:39PM +0800, Yang Xu wrote:
> > > 
> > > 
> > >   on 2019/10/15 14:27, Yang Xu wrote:
> > > > 
> > > > 
> > > > on 2019/10/15 0:39, Darrick J. Wong wrote:
> > > > > On Tue, Oct 08, 2019 at 10:39:59AM +0800, Yang Xu wrote:
> > > > > > 
> > > > > > 
> > > > > > on 2019/10/07 23:12, Darrick J. Wong wrote:
> > > > > > > On Mon, Oct 07, 2019 at 03:15:15PM +0800, Yang Xu wrote:
> > > > > > > > On old kernel, since commit ded188b8609 ("xfs: Fix the
> > > > > > > > situation that mount
> > > > > > > > operation rejects corrupted XFS") running this case got
> > > > > > > > the mismatched output,
> > > > > > > > as below:
> > > > > > > 
> > > > > > > But why did the output mismatch?  Did the fs heal itself?  Did
> > > > > > > allocating 5 more files somehow avoid touching the finobt?  Is the
> > > > > > > assignment logic in the loop broken?
> > > > > > 
> > > > > > The output mismatch because on old kernel, we can mount the
> > > > > > corrupted xfs
> > > > > > and touch action will be refused. so broken is equal to 0.
> > > > > > The fs doesn't heal ifself.
> > > > > > allocating 5 more file will touch the finobt.
> > > > > > 
> > > > > > You can see this url
> > > > > > https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git/commit/?id=ded188b86096e2845e59dedae6050c7f254a96b
> > > > > > 
> > > > > > 
> > > > > > eg xfs/087, they all delete "broken=0" before allocationg 5 more file.
> > > > > > commit ded188b86 compatibled old kernel(permit mount and refuse
> > > > > > touch) and
> > > > > > new kernel(refuse mount) behavior on corrupted xfs.  Or, I misunderstand
> > > > > > this case?
> > > > > 
> > > > > How old is the kernel?  At some point (4.10, I think?) we added a patch
> > > > > to reserve metadata blocks for future free inode btree expansion.  That
> > > > > required us to count the blocks in the finobt, at which point xfs/097's
> > > > > behavior changed such that the fs doesn't mount after the test corrupts
> > > > > the finobt.
> > > > I test this case on kernel-3.10.0-1062.el7.x86_64.
> > > > I find the patch you said to reserve metadata blocks for future free
> > > > inode btree expansion. This kernel doesn't backport this commit 76d771b4
> > > > ("xfs: use per-AG reservations for the finobt"), so it permmits to
> > > > mount.
> > > > 
> > > > I can understand your meaning. But from xfstests commit ded188b86, it
> > > > looks like refuse touch or refuse mount is acceptable for xfstests.
> > > > 
> > > > Also, xfs/087 is a similar case but it sets broken=1 instead of broken
> > > > =0.  Before this kernel commit 76d771b4, xfs/087(xfs/097) permits mount
> > > > and refuse touch, after this commit, xfs/087(xfs/097) refuses mount.
> > > > I think we should keep xfs/097 consistent with xfs/087. What do you
> > > > think about it?
> > > > 
> > > > ps:my patch is intend to fix the inconsistent of broken assignment
> > > > operation that xfstests commit ded188b86 introduced.
> > > Hi Darrick
> > >    Do you have some questions on this patch?
> > 
> > Does it still pass on upstreeam 5.4?
> 
> Of course. It still can pass on upstream 5.4.
> 
> --------------------------------------
> echo "+ mount image && modify files"
> broken=1
> //on kernel with commit d771b4 ("xfs: use per-AG reservations for the
> //finobt", it will not run into this if judgement, so broken=1.
> //on kernel without this kernel commit, it will run into this if //judgement
> and touch will be refused, so broken is still equal to 1.
> if _try_scratch_mount >> $seqres.full 2>&1; then
>         for x in `seq 65 70`; do
>                 touch "${TESTFILE}.${x}" 2> /dev/null && broken=0
>         done
>         umount "${SCRATCH_MNT}"
> fi
> --------------------------------------

Ah, ok.  Looks good to me then.  Sorry I was a little slow on the
uptake. :/

Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>

--D

> 
> > 
> > --D
> > 
> > > Hi Eryu
> > >     What do you think about this patch(I only want to keep xfs/097 consistent
> > > with xfs/087).
> > > > 
> > > > Thanks
> > > > Yang Xu
> > > > 
> > > > > 
> > > > > --D
> > > > > 
> > > > > > > 
> > > > > > > --D
> > > > > > > 
> > > > > > > > -----------------------------------
> > > > > > > >     + check fs
> > > > > > > >     + corrupt image
> > > > > > > >     + mount image && modify files
> > > > > > > > -broken: 1
> > > > > > > > +broken: 0
> > > > > > > >     + repair fs
> > > > > > > >     + mount image (2)
> > > > > > > > ------------------------------------
> > > > > > > > 
> > > > > > > > It fails because the broken is always equal to 0 when
> > > > > > > > _try_scratch_mount
> > > > > > > > succeed. So remove this wrong assignment operation.
> > > > > > > > 
> > > > > > > > Signed-off-by: Yang Xu <xuyang2018.jy@xxxxxxxxxxxxxx>
> > > > > > > > ---
> > > > > > > >     tests/xfs/097 | 2 --
> > > > > > > >     1 file changed, 2 deletions(-)
> > > > > > > > 
> > > > > > > > diff --git a/tests/xfs/097 b/tests/xfs/097
> > > > > > > > index 1cb7d69c..20791738 100755
> > > > > > > > --- a/tests/xfs/097
> > > > > > > > +++ b/tests/xfs/097
> > > > > > > > @@ -81,8 +81,6 @@ done
> > > > > > > >     echo "+ mount image && modify files"
> > > > > > > >     broken=1
> > > > > > > >     if _try_scratch_mount >> $seqres.full 2>&1; then
> > > > > > > > -
> > > > > > > > -    broken=0
> > > > > > > >         for x in `seq 65 70`; do
> > > > > > > >             touch "${TESTFILE}.${x}" 2> /dev/null && broken=0
> > > > > > > >         done
> > > > > > > > -- 
> > > > > > > > 2.18.1
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > > 
> > > > > > 
> > > > > 
> > > > > 
> > > > 
> > > > 
> > > 
> > > 
> > 
> > 
> 
> 



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