Re: LibPATA code issues / 2.6.15.4

Mark Lord wrote:

sdb: Current: sense key: Medium Error
Additional sense: Unrecovered read error - auto reallocate failed
end_request: I/O error, dev sdb, sector 398283329
raid1: Disk failure on sdb2, disabling device.
Operation continuing on 1 devices


Oh good, *now* we've gotten somewhere!!

Albert / Jens / Jeff:

The command failing above is SCSI WRITE_10, which is being
translated into ATA_CMD_WRITE_FUA_EXT by libata.

This command fails -- unrecognized by the drive in question.
But libata reports it (most incorrectly) as a "medium error",
and the drive is taken out of service from its RAID.

Bad, bad, and worse.

Libata should really recover from this, by recognizing that
the command was rejected, and replacing it with a simple
WRITE_EXT instead. Possibly followed by FLUSH_CACHE.

So.. I've forgotten who put FUA into libata, but hopefully
it's one of the folks on the CC: list, and that nice person
can now generate a patch to fix this bug somehow.

Thanks Mark

I'm glad it's a bug and not bad hardware.

I am quite concerned that the basic effect of just booting a practically
vanilla 2.6.16-rc4 like this was to fry my raid array.

Luckily it dropped 2 (of 3) disks so quickly that the event counter was
the same allowing an easy rebuild.

2.6.15 has similar issues but they seem to happen *very* infrequently by
comparison - this hit me several times during a single boot.

Should Linus (cc'ed) hold off on 2.6.16 because of this or not?

David

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