| Message ID | CAMGffEmZMWSTSP3VRxn8K_ZWG3qvRWeKOjzPJN8V4ZZ8Fa_xGA@mail.gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
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@profitbricks.com> > 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@gmx.de> > Suggested-by: James Bottomley <James.Bottomley@HansenPartnership.com> > Signed-off-by: Jack Wang <jinpu.wang@profitbricks.com> > --- > 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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, 2016-05-13 at 06:51 -0700, James Bottomley wrote: > 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. OK, I checked, we're covered by the wait_for check at the bottom of the switch which will automatically fail the command and not retry if we've exceeded the timeout. James -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From 99eab170653544fa1e1bc9511ec055ba70e183d2 Mon Sep 17 00:00:00 2001 From: Jack Wang <jinpu.wang@profitbricks.com> 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@gmx.de> Suggested-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Jack Wang <jinpu.wang@profitbricks.com> --- 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