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From 22e47c104ff73885357a0be7b94270f3955427ea Mon Sep 17 00:00:00 2001
From: Jeffrey Cody <jcody@redhat.com>
Date: Tue, 17 Jan 2017 19:51:31 +0100
Subject: [PATCH 2/3] gluster: Correctly propagate errors when volume isn't
 accessible

RH-Author: Jeffrey Cody <jcody@redhat.com>
Message-id: <963a714d4eae919df79e2031e02c77af5a8697e2.1484682588.git.jcody@redhat.com>
Patchwork-id: 73256
O-Subject: [RHEL-7.4 qemu-kvm 2/3] gluster: Correctly propagate errors when volume isn't accessible
Bugzilla: 1151859
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>

From: Peter Krempa <pkrempa@redhat.com>

The docs for glfs_init suggest that the function sets errno on every
failure. In fact it doesn't. As other functions such as
qemu_gluster_open() in the gluster block code report their errors based
on this fact we need to make sure that errno is set on each failure.

This fixes a crash of qemu-img/qemu when a gluster brick isn't
accessible from given host while the server serving the volume
description is.

Thread 1 (Thread 0x7ffff7fba740 (LWP 203880)):
 #0  0x00007ffff77673f8 in glfs_lseek () from /usr/lib64/libgfapi.so.0
 #1  0x0000555555574a68 in qemu_gluster_getlength ()
 #2  0x0000555555565742 in refresh_total_sectors ()
 #3  0x000055555556914f in bdrv_open_common ()
 #4  0x000055555556e8e8 in bdrv_open ()
 #5  0x000055555556f02f in bdrv_open_image ()
 #6  0x000055555556e5f6 in bdrv_open ()
 #7  0x00005555555c5775 in bdrv_new_open ()
 #8  0x00005555555c5b91 in img_info ()
 #9  0x00007ffff62c9c05 in __libc_start_main () from /lib64/libc.so.6
 #10 0x00005555555648ad in _start ()

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 4557117d9eed8cadc360aec23b42fc39a7011864)
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block/gluster.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/block/gluster.c b/block/gluster.c
index 248a031..5266dce 100644
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -224,6 +224,11 @@ static struct glfs *qemu_gluster_init(GlusterConf *gconf, const char *filename,
                          "volume=%s image=%s transport=%s", gconf->server,
                          gconf->port, gconf->volname, gconf->image,
                          gconf->transport);
+
+        /* glfs_init sometimes doesn't set errno although docs suggest that */
+        if (errno == 0)
+            errno = EINVAL;
+
         goto out;
     }
     return glfs;
@@ -484,7 +489,7 @@ static int qemu_gluster_create(const char *filename,
 
     glfs = qemu_gluster_init(gconf, filename, errp);
     if (!glfs) {
-        ret = -EINVAL;
+        ret = -errno;
         goto out;
     }
 
-- 
1.8.3.1