Re: generic/456 regression on 5.7-rc1, 1k test case

[Eric Whitney <enwlinux@gmail.com>]

* Ritesh Harjani <riteshh@linux.ibm.com>:
> Hello Eric,
> 
> On 4/14/20 8:22 AM, Ritesh Harjani wrote:
> > Hello Eric,
> > 
> > On 4/14/20 1:42 AM, Eric Whitney wrote:
> > > I'm seeing consistent failures for generic/456 while running
> > > kvm-xfstests' 1k
> > > test case on 5.7-rc1.  This is with an x86-64 test appliance root
> > > file system
> > > image dated 23 March 2020.
> > > 
> > > The test fails when e2fsck reports "inconsistent fs: inode 12, i_size is
> > > 147456, should be 163840".
> > > 
> > > Bisecting 5.7-rc1 identified the following patch as the cause:
> > > ext4: don't set dioread_nolock by default for blocksize < pagesize
> > > (626b035b816b).  Reverting the patch in 5.7-rc1 reliably eliminates
> > > the test
> > > failure.
> > > 
> > 
> > Since you could reliably reproduce it. Could you please try with this
> > patch and see if this fixes it for you?
> > 
> > https://patchwork.ozlabs.org/project/linux-ext4/patch/20200331105016.8674-1-jack@suse.cz/
> 
> 
> Ok, so after updating the xfstests to latest, I could reliably reproduce
> generic/456 failing on x86 with 1K blocksize on my setup too.
> Although, with my limited testing, I couldn't see this issue on Power (where
> blocksize == 4K and PAGESIZE=64K).
> 
> But either ways, after applying above patch the tests always passes for
> me (tested on x86). So this should indeed fix your reported problem.
> Saw an email too that Ted has now picked up this patch.
> 
> 
> -ritesh
>

Hi, Ritesh:

Thanks for pointing out that patch - I'd not noticed it.  Out of general
thoroughness, I applied it to 5.7-rc1 and ran the entire 1k test case
without a generic/456 failure or any other regressions.  So, that should
resolve this issue.  (5.7-rc1 otherwise looks good to me generally after
regression against 5.6 on x86_64).

Thanks very much for your help!

Eric