BUG 817252 - xfs qa 013 trips assertion

[pv@xxxxxxxxxxxxx (dxm@xxxxxxxxxxxx)]

View Incident: 
http://co-op.engr.sgi.com/BugWorks/code/bwxquery.cgi?search=Search&wlong=1&view_type=Bug&wi=817252

Submitter : dxm                       Submitter Domain : engr               
Assigned Engineer : nb                Assigned Domain : sgi.com             
Assigned Group : xfs-linux            Category : software                   
Customer Reported : F                 Priority : 2                          
Project : xfs-linux                   Status : open                         
Description :
fuzzy.melbourne - sgi 1200, scsi, 2 cpu:

xfs qa 013 now reliably trips this assertion:

XFS assertion failed: ismrlocked(io->io_iolock, MR_UPDATE), file: xfs_lrw.c, 
line: 414
kernel BUG at debug.c:48!

Entering kdb (current=0xc3e30000, pid 1475) on processor 0 Oops: invalid operand
due to oops @ 0xc8827d7d
eax = 0x0000001a ebx = 0xc5592a18 ecx = 0x00000001 edx = 0x00000001 
esi = 0xc5592918 edi = 0x00000000 esp = 0xc3e31e30 eip = 0xc8827d7d 
ebp = 0xc3e31e3c xss = 0x00000018 xcs = 0x00000010 eflags = 0x00010286 
xds = 0x00000018 xes = 0x00000018 origeax = 0xffffffff &regs = 0xc3e31dfc
[0]kdb> bt
    EBP       EIP         Function(args)
0xc3e31e3c 0xc8827d7d [xfs_support]assfail+0x2d (0xc89ba980, 0xc89ba817, 0x19e)
                               xfs_support .text 0xc8827060 0xc8827d50 
0xc8827d84
0xc3e31ebc 0xc899c2a9 [xfs]xfs_zero_eof+0x79 (0xc400cd24, 0xc5592a18, 0x17b000, 
0x0, 0xa8cea)
                               xfs .text 0xc8929060 0xc899c230 0xc899c8e0
0xc3e31f34 0xc899cb8e [xfs]xfs_write+0x2ae (0xc5592918, 0xc3e31f74, 0x0, 0x0, 
0x0)
                               xfs .text 0xc8929060 0xc899c8e0 0xc899cdfc
0xc3e31f98 0xc899872c [xfs]linvfs_write+0x138 (0xc4aa0440, 0x40116000, 0x5000, 
0xc4aa0460)
                               xfs .text 0xc8929060 0xc89985f4 0xc8998754
0xc3e31fbc 0xc01349e5 sys_write+0x95 (0x3, 0x40116000, 0x5000, 0x482967d7, 
0x59b7)
                               kernel .text 0xc0100000 0xc0134950 0xc0134a20
           0xc01090d7 system_call+0x33
                               kernel .text 0xc0100000 0xc01090a4 0xc01090dc