From 0a37ee43ee671c7cbd02110f9e968dbd530d2a4e Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Fri, 6 Jul 2018 17:56:52 +0200
Subject: [PATCH 192/268] pr-helper: fix assertion failure on failed multipath
 PERSISTENT RESERVE IN
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RH-Author: Paolo Bonzini <pbonzini@redhat.com>
Message-id: <20180706175659.30615-3-pbonzini@redhat.com>
Patchwork-id: 81246
O-Subject: [RHEL7.6 qemu-kvm-rhev PATCH 2/9] pr-helper: fix assertion failure on failed multipath PERSISTENT RESERVE IN
Bugzilla: 1533158
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Michal Privoznik <mprivozn@redhat.com>

The response size is expected to be zero if the SCSI status is not
"GOOD", but nothing was resetting it.

This can be reproduced simply by "sg_persist -s /dev/sdb" where /dev/sdb
in the guest is a scsi-block device corresponding to a multipath device
on the host.

Before:

  PR in (Read full status): Aborted command

and on the host:

  prh_write_response: Assertion `resp->sz == 0' failed.

After:

  PR in (Read full status): bad field in cdb or parameter list
  (perhaps unsupported service action)

Reported-by: Jiri Belka <jbelka@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
(cherry picked from commit 86933b4e7879e427e03365bf352c0964640cb37b)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 scsi/qemu-pr-helper.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/scsi/qemu-pr-helper.c b/scsi/qemu-pr-helper.c
index 4057cf3..0218d65 100644
--- a/scsi/qemu-pr-helper.c
+++ b/scsi/qemu-pr-helper.c
@@ -558,7 +558,11 @@ static int do_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
 #ifdef CONFIG_MPATH
     if (is_mpath(fd)) {
         /* multipath_pr_in fills the whole input buffer.  */
-        return multipath_pr_in(fd, cdb, sense, data, *resp_sz);
+        int r = multipath_pr_in(fd, cdb, sense, data, *resp_sz);
+        if (r != GOOD) {
+            *resp_sz = 0;
+        }
+        return r;
     }
 #endif
 
-- 
1.8.3.1