xfs_force_shutdown called from file fs/xfs/xfs_trans_buf.c

[Jay Sullivan <jpspgd@xxxxxxx>]

(Sorry if this is a dupe to the list; it has been a long day.)

I have an XFS filesystem that has had the following happen twice in 3  
months, both times an impossibly large block number was requested.   
Unfortunately my logs don?t go back far enough for me to know if it  
was the _exact_ same block both times?  I?m running xfsprogs 2.8.21.   
Excerpt from syslog (hostname obfuscated to ?servername? to protect  
the innocent):

##
Nov  1 14:06:32 servername dm-1: rw=0, want=39943195856896,  
limit=7759462400
Nov  1 14:06:32 servername I/O error in filesystem ("dm-1") meta-data  
dev dm-1 block 0x245400000ff8       ("xfs_trans_read_buf") error 5 buf  
count 4096
Nov  1 14:06:32 servername xfs_force_shutdown(dm-1,0x1) called from  
line 415 of file fs/xfs/xfs_trans_buf.c.  Return address = 0xc02baa25
Nov  1 14:06:32 servername Filesystem "dm-1": I/O Error Detected.   
Shutting down filesystem: dm-1
Nov  1 14:06:32 servername Please umount the filesystem, and rectify  
the problem(s)
###

I ran xfs_repair ?L on the FS and it could be mounted again, but how  
long until it happens a third time?  What concerns me is that this is  
a FS smaller than 4TB and 39943195856896 (or 0x245400000ff8) seems  
like a block that I would only have if my FS was muuuuuch larger.  The  
following is output from some pertinent programs:

###
servername ~ # xfs_info /mnt/san
meta-data=/dev/servername-sanvg01/servername-sanlv01 isize=256     
agcount=5, agsize=203161600 blks
          =                       sectsz=512   attr=2
data     =                       bsize=4096   blocks=969932800,  
imaxpct=25
          =                       sunit=0      swidth=0 blks,  
unwritten=1
naming   =version 2              bsize=4096
log      =internal               bsize=4096   blocks=32768, version=1
          =                       sectsz=512   sunit=0 blks, lazy- 
count=0
realtime =none                   extsz=4096   blocks=0, rtextents=0
servername ~ # mount
/dev/sda3 on / type ext3 (rw,noatime,acl)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec)
udev on /dev type tmpfs (rw,nosuid)
devpts on /dev/pts type devpts (rw,nosuid,noexec)
shm on /dev/shm type tmpfs (rw,noexec,nosuid,nodev)
usbfs on /proc/bus/usb type usbfs  
(rw,noexec,nosuid,devmode=0664,devgid=85)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc  
(rw,noexec,nosuid,nodev)
nfsd on /proc/fs/nfsd type nfsd (rw)
/dev/mapper/servername--sanvg01-servername--sanlv01 on /mnt/san type  
xfs (rw,noatime,nodiratime,logbufs=8,attr2)
/dev/mapper/servername--sanvg01-servername--rendersharelv01 on /mnt/ 
san/rendershare type xfs (rw,noatime,nodiratime,logbufs=8,attr2)
rpc_pipefs on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
servername ~ # uname -a
Linux servername 2.6.20-gentoo-r8 #7 SMP Fri Jun 29 14:46:02 EDT 2007  
i686 Intel(R) Xeon(TM) CPU 3.20GHz GenuineIntel GNU/Linux
###

Does anyone know if this points to a bad block on a disk or if  
something is corrupted and can be fixed with some expert knowledge of  
xfs_db?

~Jay

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