BUG 799616 - ASSERT fail imap.br_startblock != DELAYSTARTBLOCK

[pv@xxxxxxxxxxxxx (dxm@xxxxxxxxxxxx)]

View Incident: 
http://co-op.engr.sgi.com/BugWorks/code/bwxquery.cgi?search=Search&wlong=1&view_type=Bug&wi=799616

Submitter : dxm                       Submitter Domain : engr               
Assigned Engineer : dxm               Assigned Domain : engr                
Assigned Group : xfs-linux            Category : software                   
Customer Reported : F                 Priority : 3                          
Project : xfs-linux                   Status : open                         
Description :
when running the xfscrash corrupt test, an ASSERT can
get tripped:

XFS assertion failed: imap.br_startblock != DELAYSTARTBLOCK, file: 
xfs_vnodeops.c, line: 5803
kernel BUG at xfs_debug.c:50!

Entering kdb (0xedeb6000) on processor 1 Panic: invalid operand
due to panic @ 0xf89028a9
eax = 0x0000001e ebx = 0x000f8fff ecx = 0xc02b6f2c edx = 0x00000000 
esi = 0x00000000 edi = 0x00000000 esp = 0xedeb79b4 eip = 0xf89028a9 
ebp = 0xedeb79c0  ss = 0x00000018  cs = 0x00000010 eflags = 0x00010246 
 ds = 0x00000018  es = 0x00000018 origeax = 0xffffffff &regs = 0xedeb7980

    EBP       EIP         Function(args)
0xedeb79c0 0xf89028a9 [xfs]assfail+0x2d (0xf8921160, 0xf892095b, 0x16ab)
                               xfs .text 0xf8894060 0xf890287c 0xf89028b0
0xedeb7a38 0xf88ffa99 [xfs]xfs_zero_remaining_bytes+0x1c1 (0xf3676040, 0xf8f45, 
0x0, 0xf8fff, 0x0)
                               xfs .text 0xf8894060 0xf88ff8d8 0xf88ffbc4
0xedeb7b1c 0xf8900156 [xfs]xfs_free_file_space+0x592 (0xf3676040, 0xf8f45, 0x0, 
0x5102a, 0x0)
                               xfs .text 0xf8894060 0xf88ffbc4 0xf89003b0
0xedeb7be0 0xf89005de [xfs]xfs_change_file_space+0x22e (0xf3676058, 0x402c582b, 
0xedeb7d34, 0x0, 0x0)
                               xfs .text 0xf8894060 0xf89003b0 0xf89007b8
0xedeb7f34 0xf890414c [xfs]xfs_ioctl+0x33c (0xf3676058, 0xf705bb40, 0xf7c79480, 
0x402c582b, 0xbffff91c)
                               xfs .text 0xf8894060 0xf8903e10 0xf8904d00
0xedeb7f58 0xf8902ec2 [xfs]linvfs_ioctl+0x56 (0xf705bb40, 0xf7c79480, 
0x402c582b, 0xbffff91c)
                               xfs .text 0xf8894060 0xf8902e6c 0xf8902ecc
0xedeb7f84 0xc014084b file_ioctl+0x14b (0xf7c79480, 0x402c582b, 0xbffff91c, 
0xedeb6000)
                               kernel .text 0xc0100000 0xc0140700 0xc0140860
0xedeb7fbc 0xc01409cd sys_ioctl+0x16d (0x3, 0x402c582b, 0xbffff91c, 0x5102a, 
0x0)
                               kernel .text 0xc0100000 0xc0140860 0xc0140a50
           0xc0109040 system_call+0x34
                               kernel .text 0xc0100000 0xc010900c 0xc0109044

The bug is related to the "resvsp" & "unresvsp" operations
in fsstress.

(fsstress -d /mnt/arch0/stress -n 1000 -p 1 -f sync=0 allocsp=0
  freesp=0)