[LU-11663] corrupt data after page-unaligned write with zfs backend lustre 2.10

• Type: Bug
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.12.0, Lustre 2.10.6
• Affects Version/s: Lustre 2.12.0, Lustre 2.10.5, Lustre 2.10.6
• Labels: llnl
• Environment: client catalyst: lustre-2.8.2_5.chaos-1.ch6.x86_64 ; server: porter lustre-2.10.5_2.chaos-3.ch6.x86_64 ; kernel-3.10.0-862.14.4.1chaos.ch6.x86_64 (RHEL 7.5 derivative)
• Severity: 2
• Assignee: Alex Zhuravlev
• Reporter: Olaf Faaland

Description

The apparent contents of a file change after dropping caches:

[root@catalyst110:toss-4371.umm1t]# ./proc6.olaf
+ dd if=/dev/urandom of=testfile20K.in bs=10240 count=2
2+0 records in
2+0 records out
20480 bytes (20 kB) copied, 0.024565 s, 834 kB/s
+ dd if=testfile20K.in of=testfile20K.out bs=10240 count=2
2+0 records in
2+0 records out
20480 bytes (20 kB) copied, 0.0451045 s, 454 kB/s
++ md5sum testfile20K.out
+ original_md5sum='1060a4c01a415d7c38bdd00dcf09dd22  testfile20K.out'
+ echo 3
++ md5sum testfile20K.out
+ echo after drop_caches 1060a4c01a415d7c38bdd00dcf09dd22 testfile20K.out 717122f4dd25f2e75834a8b21c79ce50 testfile20K.out
after drop_caches 1060a4c01a415d7c38bdd00dcf09dd22 testfile20K.out 717122f4dd25f2e75834a8b21c79ce50 testfile20K.out                                                                        

[root@catalyst110:toss-4371.umm1t]# cat proc6.olaf
#!/bin/bash

set -x

dd if=/dev/urandom of=testfile.in bs=10240 count=2
dd if=testfile.in of=testfile.out bs=10240 count=2

#dd if=/dev/urandom of=testfile.in bs=102400 count=2
#dd if=testfile.in of=testfile.out bs=102400 count=2
original_md5sum=$(md5sum testfile.out)
echo 3 >/proc/sys/vm/drop_caches

echo after drop_caches $original_md5sum $(md5sum testfile.out)

Issue Links

• is related to: LU-11697 BAD WRITE CHECKSUM with t10ip4K and t10ip512 checksums
• is related to: LU-11729 ARM: sanity test_810: BAD WRITE CHECKSUM with adler
• is related to: LU-10683 write checksum errors
• is related to: LU-11798 cur_grant goes to 0 and never increases with 2.8 client and 2.10 server