Bug#934331: linux: backport "dm: disable DISCARD if the underlying storage no longer supports it"?
Control: forwarded 934331 https://lore.kernel.org/stable/20190818155941.GA26766@eldamar.local/
Hi Chris,
On Fri, Aug 09, 2019 at 11:12:36PM +0200, Chris Hofstaedtler wrote:
> Package: linux
> Version: 4.9.168-1+deb9u4
> Severity: normal
>
> Hi!
>
> Today I ran into an issue that matches the description of upstream
> commit bcb44433bba5eaff293888ef22ffa07f1f0347d6:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bcb44433bba5eaff293888ef22ffa07f1f0347d6
>
> > dm: disable DISCARD if the underlying storage no longer supports it
> >
> > Storage devices which report supporting discard commands like
> > WRITE_SAME_16 with unmap, but reject discard commands sent to the
> > storage device. This is a clear storage firmware bug but it doesn't
> > change the fact that should a program cause discards to be sent to a
> > multipath device layered on this buggy storage, all paths can end up
> > failed at the same time from the discards, causing possible I/O loss.
> >
> > The first discard to a path will fail with Illegal Request, Invalid
> > field in cdb, e.g.:
> > kernel: sd 8:0:8:19: [sdfn] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
> > kernel: sd 8:0:8:19: [sdfn] tag#0 Sense Key : Illegal Request [current]
> > kernel: sd 8:0:8:19: [sdfn] tag#0 Add. Sense: Invalid field in cdb
> > kernel: sd 8:0:8:19: [sdfn] tag#0 CDB: Write same(16) 93 08 00 00 00 00 00 a0 08 00 00 00 80 00 00 00
> > kernel: blk_update_request: critical target error, dev sdfn, sector 10487808
>
> The patch was CC'ed to stable but doesn't seem to appear in 4.19.y.
>
> Unfortunately this appears to be a transient bug in the storage
> firmware, so I don't know how to reproduce it -- deleting and rescanning
> the sdX device has cleared the repeated error condition for now.
>
> However I'd really like to avoid corrupting the involved file systems,
> so if bcb44433bba5eaff293888ef22ffa07f1f0347d6 could make it into either
> the 4.9 branch or the 4.19 branch, that'd be lovely.
>
> I've also asked the storage vendor what they think about this, but I'm
> not going to hold my breath.
I have sent
https://lore.kernel.org/stable/20190818155941.GA26766@eldamar.local/
let's see what happends. 4.19 should be easier than 4.9, but given Ben
has backported the change to 3.16.72 this should be possible for both
4.9 and 4.19.
Regards,
Salvatore
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