We have experienced an LBUG on one of ours OSS servers which I have not seen before.

LustreError: 16066:0:(filter_io_26.c:344:filter_do_bio()) ASSERTION(rw == OBD_BRW_READ) failed
LustreError: 16066:0:(filter_io_26.c:344:filter_do_bio()) LBUG
Pid: 16066, comm: ll_ost_io_126

Now after rebooting that OSS same LBUG is triggered as soon as OSTs finishes recovery and start servicing their data. Has anyone seen this before ?

Our environment:
servers:  RHEL6 2.6.32-220.17.1.el6_lustre.x86_64 Lustre-2.1.2
clients:  RHEL6 2.6.32-358.6.2.el6.x86_64 Lustre-2.1.5 patchless

We have resolved this by first identifying which OST was involved in the LBUG and then running fsck on that OST. File system check found an incorrect inode number and repaired it. This is very worrying though how this corruption has crept in onto the filesystem. We did not experienced any hardware problems or unexpected crashes of the storage that could cause this.

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Wojciech Turek