From 89bdd1d20e9ccde41f271fe5dc22c355cbbc822a Mon Sep 17 00:00:00 2001
From: Jeffrey Cody <jcody@redhat.com>
Date: Tue, 11 Feb 2014 16:14:28 +0100
Subject: [PATCH 22/28] block: Fix bdrv_commit return value

RH-Author: Jeffrey Cody <jcody@redhat.com>
Message-id: <5019e17d0114b49c58c42415e79b81abdcb648d3.1392134912.git.jcody@redhat.com>
Patchwork-id: 57218
O-Subject: [RHEL7 qemu-kvm PATCH 4/6] block: Fix bdrv_commit return value
Bugzilla: 1047254
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Markus Armbruster <armbru@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

From: Kevin Wolf <kwolf@redhat.com>

bdrv_commit() could return 0 or 1 on success, depending on whether or
not the last sector was allocated in the overlay and whether the overlay
format had a .bdrv_make_empty callback.

Most callers ignored it, but qemu-img commit would print an error
message while the operation actually succeeded.

Also clean up the handling of I/O errors to return the real error code
instead of -EIO.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
(cherry picked from commit dabfa6cc2e2a06269026fcb42772894f67bd0c3e)
---
 block.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block.c |   15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/block.c b/block.c
index c7aa285..642e8d6 100644
--- a/block.c
+++ b/block.c
@@ -2006,13 +2006,13 @@ int bdrv_commit(BlockDriverState *bs)
             goto ro_cleanup;
         }
         if (ret) {
-            if (bdrv_read(bs, sector, buf, n) != 0) {
-                ret = -EIO;
+            ret = bdrv_read(bs, sector, buf, n);
+            if (ret < 0) {
                 goto ro_cleanup;
             }
 
-            if (bdrv_write(bs->backing_hd, sector, buf, n) != 0) {
-                ret = -EIO;
+            ret = bdrv_write(bs->backing_hd, sector, buf, n);
+            if (ret < 0) {
                 goto ro_cleanup;
             }
         }
@@ -2020,6 +2020,9 @@ int bdrv_commit(BlockDriverState *bs)
 
     if (drv->bdrv_make_empty) {
         ret = drv->bdrv_make_empty(bs);
+        if (ret < 0) {
+            goto ro_cleanup;
+        }
         bdrv_flush(bs);
     }
 
@@ -2027,9 +2030,11 @@ int bdrv_commit(BlockDriverState *bs)
      * Make sure all data we wrote to the backing device is actually
      * stable on disk.
      */
-    if (bs->backing_hd)
+    if (bs->backing_hd) {
         bdrv_flush(bs->backing_hd);
+    }
 
+    ret = 0;
 ro_cleanup:
     g_free(buf);
 
-- 
1.7.1