On Sat, Jan 19, 2008 at 08:56:31PM -0600, James Bottomley wrote: .... > > it's children a few days ago (probably with 2.6.22-14-generic (Ubuntu > > kernel). I've appended everything for PID 17972 (which is only 12k, full > > output is 559KB). Key bit is this: > > 17972 _llseek(3, 31129600, [31129600], SEEK_SET) = 0 > > 17972 read(3, <unfinished ...> > > 17972 <... read resumed> 0x804dc80, 512) = -1 EIO (Input/output error) > > > > given the device reports "60801 512-byte hardware sectors (31 MB)" > > and "31129600/512 == 60800"...it's obvious vol_id is trying to read > > the last sector on the disk (I assume it's to verify the size). > > ISTR "reading the last sector" caused problems else where. > > I'll try to hunt that down. > > If this is the problem, it ought to be reproducible without vol_id by > doing > > dd bs=512b if=/dev/<dev> of=/dev/null seek=60800 count=1 root@mb500:~ # dd bs=512b if=/dev/sda of=/dev/null seek=60800 count=1 1+0 records in 1+0 records out 262144 bytes (262 kB) copied, 0.433933 seconds, 604 kB/s but since 512B is the default (I thought), I tried: root@mb500:~ # dd if=/dev/sda of=/dev/null seek=60800 count=1 1+0 records in 1+0 records out 512 bytes (512 B) copied, 0.0239289 seconds, 21.4 kB/s and got different output....wth? Oh...and you mean "skip", not "seek"...no wonder that worked. root@mb500:~ # strace -o strace-dd-HPr707.out dd if=/dev/sda of=/dev/null skip=60800 count=1 dd: reading `/dev/sda': Input/output error 0+0 records in 0+0 records out 0 bytes (0 B) copied, 55.7303 seconds, 0.0 kB/s dmesg output: Jan 19 19:08:12 localhost kernel: usb 1-1.1.4: reset full speed USB device using uhci_hcd and address 8 Jan 19 19:08:37 localhost last message repeated 3 times Jan 19 19:08:37 localhost kernel: sd 3:0:0:0: scsi: Device offlined - not ready after error recovery Jan 19 19:08:37 localhost kernel: sd 3:0:0:0: [sda] Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK,SUGGEST_OK Jan 19 19:08:37 localhost kernel: end_request: I/O error, dev sda, sector 60800 > There is a READ_CAPACITY bug where incompetent usb vendors misread the > SCSI standard and actually report one sector more than the actual > capacity (and crash when this is accessed), but let's verify first. This seems to be exactly the case. What's the work around? thanks, grant - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
