Re: [PATCH 2/2] scsi: scsi_debug: reset protection information on zone reset

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [Low] scsi: scsi_debug: Fixes trailer cites wrong commit for zone
  zeroing
--

commit 9eaf9f0aa21e38b43d9e35227a9895fa8453a7ae
Author: Tal Zussman <tz2294@columbia.edu>

> scsi: scsi_debug: reset protection information on zone reset
>
> zbc_rwp_zone() zeroes the data of a zone that is reset, but leaves the
> protection information of its previous contents in place. Reads of a
> zoned device are not limited to the blocks below the write pointer, so
> with DIX enabled reading those blocks back fails the guard check.
>
> Write to a zone, reset it and read it back:
>
>   # modprobe scsi_debug zbc=managed sector_size=4096 dev_size_mb=64 \
>         zone_size_mb=4 dif=1 dix=1
>   # dd if=/dev/urandom of=/dev/sda bs=1M count=1 seek=8 oflag=direct
>   # blkzone reset -o 16384 -c 1 /dev/sda
>   # dd if=/dev/sda of=/dev/null bs=1M count=1 skip=8 iflag=direct
>   dd: error reading '/dev/sda': Invalid or incomplete multibyte or wide character
>
> The read fails with EILSEQ, and the guard tag that the device reports
> is still that of the data that was written, while the block now holds
> zeroes:
>
> scsi_debug:dif_verify: GUARD check failed on sector 2048 rcvd 0x288f, data 0x0000
> protection error, dev sda, sector 16384 op 0x0:(READ) flags 0x10800 phys_seg 256 prio class 2
>
> Reset the protection information of the zeroed blocks to 0xff, as
> unmap_region() does, so that they are not checked until they are
> written again.
>
> Fixes: f0d1cf9378bd ("scsi: scsi_debug: Add ZBC zone commands")
> Signed-off-by: Tal Zussman <tz2294@columbia.edu>

[Severity: Low]
Should the Fixes: tag reference 2d62253eb1b6 ("scsi: scsi_debug: Zero
clear zones at reset write pointer") instead?

Commit f0d1cf9378bd ("scsi: scsi_debug: Add ZBC zone commands") did not
zero sip->storep in zbc_rwp_zone(); zeroing zone data on reset without
resetting sip->dif_storep was added in 2d62253eb1b6 ("scsi: scsi_debug:
Zero clear zones at reset write pointer").

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261110-scsi-debug-zone-reset-v1-0-28cb9184b5ea@columbia.edu?part=2