On Fri, 2016-05-13 at 10:07 +0200, Jinpu Wang wrote: > Hi James, and all, > > I guess you're busy on other staff, so I create patch below as you > suggested, I think we also need this into stable. No, I'll do it, but I just wanted to verify that we don't get into an infinite retry loop on any conditions. James > From 99eab170653544fa1e1bc9511ec055ba70e183d2 Mon Sep 17 00:00:00 > 2001 > From: Jack Wang <jinpu.wang@xxxxxxxxxxxxxxxx> > Date: Fri, 13 May 2016 09:53:21 +0200 > Subject: [PATCH] scsi: don't fail zero length request too early > > We hit IO error in our production when SYNC on multipath devices > during resize > device on target side, the problem turns out scsi driver passes up as > IO > error when sense data is UNIT_ATTENTION and ASC && ASCQ indicate > Capacity data has changed, even storage side sync the data properly. > > Dig it further turns out we need special case on zero length commands > (currently only FLUSH), when it fails, we always need to drop down > into retry code. > > Reported-by: Sebastian Parschauer <s.parschauer@xxxxxx> > Suggested-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxxxxxxxxx> > --- > drivers/scsi/scsi_lib.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 8106515..5a97866 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -911,9 +911,12 @@ void scsi_io_completion(struct scsi_cmnd *cmd, > unsigned int good_bytes) > } > > /* > - * If we finished all bytes in the request we are done now. > + * special case: failed zero length commands always need to > + * drop down into the retry code. Otherwise, if we finished > + * all bytes in the request we are done now. > */ > - if (!scsi_end_request(req, error, good_bytes, 0)) > + if (!(good_bytes == 0 && blk_rq_bytes(req) == 0 && result != 0) && > + !scsi_end_request(req, error, good_bytes, 0)) > return; > > /* > -- > 1.9.1 > -- 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
