I was using a Sun ST2510 device (iSCSI) and a special "block device"
appeared which is used by SUN Common Array Manager in-band management.

However it also appeared as a block device and caused some IO error:

[  716.868000] scsi 15:0:0:31: Direct-Access     SUN      Universal Xport  0735 PQ: 0 ANSI: 5
[  716.868000] qla4xxx 0000:04:01.1: scsi(15:0:0:31): Enabled tagged queuing, queue depth 32.
[  716.868000] sd 15:0:0:31: [sdf] 40960 512-byte hardware sectors (21 MB)
[  716.868000] sd 15:0:0:31: [sdf] Write Protect is off
[  716.868000] sd 15:0:0:31: [sdf] Mode Sense: 77 00 10 08
[  716.868000] sd 15:0:0:31: [sdf] Write cache: disabled, read cache: enabled, supports DPO and FUA
[  716.868000] sd 15:0:0:31: [sdf] 40960 512-byte hardware sectors (21 MB)
[  716.868000] sd 15:0:0:31: [sdf] Write Protect is off
[  716.868000] sd 15:0:0:31: [sdf] Mode Sense: 77 00 10 08
[  716.872000] sd 15:0:0:31: [sdf] Write cache: disabled, read cache: enabled, supports DPO and FUA
[  716.872000]  sdf: unknown partition table
[  716.932000] sd 15:0:0:31: [sdf] Attached SCSI disk
[  716.932000] sd 15:0:0:31: Attached scsi generic sg6 type 0
[  717.412000] end_request: I/O error, dev sdf, sector 40
[  717.412000] Buffer I/O error on device sdf, logical block 5
[  717.412000] Buffer I/O error on device sdf, logical block 6
[  717.412000] Buffer I/O error on device sdf, logical block 7
[  717.412000] Buffer I/O error on device sdf, logical block 8
[  717.412000] Buffer I/O error on device sdf, logical block 9
[  717.412000] Buffer I/O error on device sdf, logical block 10
[  717.412000] Buffer I/O error on device sdf, logical block 11
[  717.412000] Buffer I/O error on device sdf, logical block 12
[  717.412000] Buffer I/O error on device sdf, logical block 13
[  717.412000] Buffer I/O error on device sdf, logical block 14

After some googling it appeared that similar issue has been solved for
SGI/IBM devices in 48690405, so here is
the patch for SUN, please apply.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>