Re: [PATCH v4 0/6] BTT error clearing rework

Kani, Toshimitsu
2017-08-01T15:29:00Z

On Mon, 2017-07-31 at 23:35 +0000, Verma, Vishal L wrote:
> On Mon, 2017-07-31 at 23:15 +0000, Kani, Toshimitsu wrote:
> > On Wed, 2017-07-26 at 17:35 -0600, Vishal Verma wrote:
:
> >
> > Step 3 clears an error and runs fine with raw and memory
> > modes.  With sector mode, however, it ends up with continuous write
> > errors like below and does not clear the error.  Do you have any
> > thoughts?
> >
> >  EXT4-fs warning (device pmem0s): ext4_end_bio:322: I/O error 10
> > writing to inode 17 (offset 1023410176 size 8388608 starting block
> > 1834752)
> >  Buffer I/O error on device pmem0s, logical block 1834752
> >  Buffer I/O error on device pmem0s, logical block 1834753
> >  Buffer I/O error on device pmem0s, logical block 1834754
> >  :
> >  nd_pmem btt0.0: io error in WRITE sector 14680064, len 4096,
> >  EXT4-fs warning (device pmem0s): ext4_end_bio:322: I/O error 10
> > writing to inode 17 (offset 1031798784 size 1052672 starting block
> > 1835008)
> >  nd_pmem btt0.0: io error in WRITE sector 14682112, len 4096,
> >  EXT4-fs warning (device pmem0s): ext4_end_bio:322: I/O error 10
> > writing to inode 17 (offset 1031798784 size 2101248 starting block
> > 1835264)
> >  :
> >  nd_pmem btt0.0: io error in WRITE sector 14698496, len 4096,
> >  nd_pmem btt0.0: io error in WRITE sector 14700544, len 4096,
> >  nd_pmem btt0.0: io error in WRITE sector 14702592, len 4096,
> >  nd_pmem btt0.0: io error in WRITE sector 14704640, len 4096,
> >  :
>
> Thanks for the test Toshi, I will try and reproduce it.
> My first guess is - are the injected errors potentially in the BTT
> metadata area towards the end?
>
> ->rw_bytes can only clear errors on properly aligned writes, and the
> btt metadata writes will be too small to clear metadata errors..

I picked an injected offset without careful thoughts, so it is possible
that I might have stepped into such area. I just tested with a block
device interface with multiple different offsets, and they failed in
clearing as well... I will look into further as well as my test setup.

Thanks,
-Toshi