[LU-1025] Lustre crc32c implementation not use final bit inversion

• Type: Improvement
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.2.0
• Affects Version/s: Lustre 2.2.0
• Assignee: Andreas Dilger
• Reporter: Alexander Boyko

Description

LU-241 add crc32c crypto hash algorithm to ost(osc) checksum. But this implementation differ from base crc32c at linux kernel(intel implementation on crc32 instruction and table crc32c implementation) at final bit inversion.

Issue Links

• is related to: LU-241 support crc32c with hardware accelerated instruction as one of lustre checksums
• Trackbacks: Changelog 2.2 version 2.2.0 Support for networks: o2iblnd OFED 1.5.4 Server support for kernels: 2.6.32220.4.2.el6 (RHEL6) Client support for unpatched kernels: 2.6.18274.18.1.el5 (RHEL5) 2.6.32220.4.2.el6 (RHEL6) 2.6.32.360....

Comments

[Build Master (Inactive)]

Integrated in lustre-master » x86_64,client,el5,inkernel #459
LU-1025 checksum: add final bit inversion for crc32c (Revision 864516e29129cb209435b4cc3ba513a9f453d383)

Result = SUCCESS
Oleg Drokin : 864516e29129cb209435b4cc3ba513a9f453d383
Files :

• lustre/include/obd_cksum.h
• lustre/osc/osc_request.c
• lustre/ost/ost_handler.c

[Build Master (Inactive)]

Integrated in lustre-master » x86_64,client,el5,ofa #459
LU-1025 checksum: add final bit inversion for crc32c (Revision 864516e29129cb209435b4cc3ba513a9f453d383)

Result = SUCCESS
Oleg Drokin : 864516e29129cb209435b4cc3ba513a9f453d383
Files :

• lustre/ost/ost_handler.c
• lustre/include/obd_cksum.h
• lustre/osc/osc_request.c

[Peter Jones]

Landed for 2.2

[Peter Jones]

Thanks Alex!

[Alexander Boyko]

done

[Peter Jones]

Alex

Could you please rebase your patch on the tip of master? The landing of the fix for LU1048 should have now addressed the reason behind the autotest failure.

Thanks

Peter

[Peter Jones]

Thanks!

[Alexander Boyko]

patch submitted to http://review.whamcloud.com/2018

[Peter Jones]

Alexander

I appreciate that this is a simple tweak to the existing code, but it would still expedite us reviewing and landing the correction if you could upload it into gerrit.

Thanks

Peter

[Alexander Boyko]

Sure, the kernel implementation example is below.

crc = crc32c(~0, part1, len1);
crc = crc32c(crc, part2, len2);
crc = crc32c(crc, part3, len3);
crc = ~crc;

Lustre implementation doesn`t do crc = ~crc. Simple fix is to add fini_cksum(cksum, cksum_type) at obd_cksum.h and call it after cksum calculation loop at osc_request.c and ost_handler.c.

u32 fini_cksum(cksum, cksum_type)
{
   if (cksum_type == OBD_CKSUM_CRC32C)
         return ~cksum;
   return cksum;
}

[Andreas Dilger]

Alexander,
thanks for the bug report. Fortunately, since the CRC32C feature was landed after the 2.1.0 release, there is still time to fix this before 2.2.0 is released.

Can you please describe the difference in the implementation in more detail. Are you planning to submit a patch?