[LU-443] Only squawk when md->start is NULL on non-zero length

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.2.0, Lustre 1.8.7
• Affects Version/s: Lustre 2.1.0
• Severity: 2
• Bugzilla ID: 21,103
• Assignee: Lai Siyao
• Reporter: Wally Wang (Inactive)

Description

Only squawk when md->start is NULL on non-zero length. The md->start == NULL check prevents anyone from creating a ME/MD with no buffer. These are used as backstop buffers to generate events when traffic has exceeded the local buffer space. Cray DVS uses these backstop buffers to generate NAK traffic, an important part of their flow control.

This is from Oracle bug 21103 attachment 32922.

Issue Links

• Trackbacks: Changelog 1.8 {}version 1.8.7wc1{} {}Support for networks: socklnd \any kernel supported by Lustre, qswlnd Qsnet kernel modules 5.20 and later, openiblnd IbGold 1.8.2, o2iblnd OFED 1.3, 1.4.1, 1.4.2, 1.5.1, 1.5.2, 1.5.3.1 and 1.5.3.2 gmlnd GM 2.1....
• 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....