Commits
Douglas Gilbert committed 32f7ef73585
[SCSI] scsi_debug: add consecutive medium errors
A useful test case for error recovery is multiple,
consecutive medium errors. When scsi_debug is started
with "opts=2" a MEDIUM ERROR is generated when block
0x1234 (4660) is read. The patch extends that to
10 consecutive blocks from 0x1234 (i.e. blocks 4660 to
4669 inclusive).
[0:0:0:0] disk ATA INTEL SSD 2CV1 /dev/sda /dev/sg0 80.0GB
[10:0:0:0] disk Linux scsi_debug 0004 /dev/sdb /dev/sg1 1.09TB
Output file not specified so no copy, just reading input
>> unrecovered read error at blk=4660, substitute zeros
...
>> unrecovered read error at blk=4669, substitute zeros
4670+10 records in
0+0 records out
10 unrecovered read errors
lowest unrecovered read lba=4660, highest unrecovered lba=4669
time to read data: 0.047943 secs at 49.87 MB/sec
BTW Change /dev/sg1 (bsg device works just as well) to
/dev/sdb to see why, with faulty media, you do not want
to use the block layer interface. Reason: time block
layer takes to do useless retries and collateral damage
to data in its 4 KB blocks (O_DIRECT mitigates the
latter).
ChangeLog:
- extend opts=2 medium error generation at block
0x1234 to 10 consecutive blocks (i.e. blocks
0x1234 to 0x123d).
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>