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From ebd7d27935a5ec9d5c72403fc1cd60af2e450e7c Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Fri, 18 Oct 2013 08:14:33 +0200
Subject: [PATCH 08/81] block: expect errors from bdrv_co_is_allocated

RH-Author: Paolo Bonzini <pbonzini@redhat.com>
Message-id: <1382084091-16636-9-git-send-email-pbonzini@redhat.com>
Patchwork-id: 54992
O-Subject: [RHEL 7.0 qemu-kvm PATCH 08/26] block: expect errors from bdrv_co_is_allocated
Bugzilla: 989646
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

Some bdrv_is_allocated callers do not expect errors, but the fallback
in qcow2.c might make other callers trip on assertion failures or
infinite loops.

Fix the callers to always look for errors.

Cc: qemu-stable@nongnu.org
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit d663640c04f2aab810915c556390211d75457704)
---
 block.c        |  7 +++++--
 block/cow.c    |  6 +++++-
 block/qcow2.c  |  4 +---
 block/stream.c |  2 +-
 qemu-img.c     | 16 ++++++++++++++--
 qemu-io.c      |  4 ++++
 6 files changed, 30 insertions(+), 9 deletions(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block.c        |    7 +++++--
 block/cow.c    |    6 +++++-
 block/qcow2.c  |    4 +---
 block/stream.c |    2 +-
 qemu-img.c     |   16 ++++++++++++++--
 qemu-io.c      |    4 ++++
 6 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/block.c b/block.c
index 46d9420..d838a3c 100644
--- a/block.c
+++ b/block.c
@@ -1815,8 +1815,11 @@ int bdrv_commit(BlockDriverState *bs)
     buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE);
 
     for (sector = 0; sector < total_sectors; sector += n) {
-        if (bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n)) {
-
+        ret = bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n);
+        if (ret < 0) {
+            goto ro_cleanup;
+        }
+        if (ret) {
             if (bdrv_read(bs, sector, buf, n) != 0) {
                 ret = -EIO;
                 goto ro_cleanup;
diff --git a/block/cow.c b/block/cow.c
index 21bceaa..5a33b46 100644
--- a/block/cow.c
+++ b/block/cow.c
@@ -212,7 +212,11 @@ static int coroutine_fn cow_read(BlockDriverState *bs, int64_t sector_num,
     int ret, n;
 
     while (nb_sectors > 0) {
-        if (cow_co_is_allocated(bs, sector_num, nb_sectors, &n)) {
+        ret = cow_co_is_allocated(bs, sector_num, nb_sectors, &n);
+        if (ret < 0) {
+            return ret;
+        }
+        if (ret) {
             ret = bdrv_pread(bs->file,
                         s->cow_sectors_offset + sector_num * 512,
                         buf, n * 512);
diff --git a/block/qcow2.c b/block/qcow2.c
index 70da5bd..f6e64d2 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -648,13 +648,11 @@ static int coroutine_fn qcow2_co_is_allocated(BlockDriverState *bs,
     int ret;
 
     *pnum = nb_sectors;
-    /* FIXME We can get errors here, but the bdrv_co_is_allocated interface
-     * can't pass them on today */
     qemu_co_mutex_lock(&s->lock);
     ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset);
     qemu_co_mutex_unlock(&s->lock);
     if (ret < 0) {
-        *pnum = 0;
+        return ret;
     }
 
     return (cluster_offset != 0) || (ret == QCOW2_CLUSTER_ZERO);
diff --git a/block/stream.c b/block/stream.c
index 9674c31..995b97b 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -120,7 +120,7 @@ wait:
         if (ret == 1) {
             /* Allocated in the top, no need to copy.  */
             copy = false;
-        } else {
+        } else if (ret >= 0) {
             /* Copy if allocated in the intermediate images.  Limit to the
              * known-unallocated area [sector_num, sector_num+n).  */
             ret = bdrv_is_allocated_above(bs->backing_hd, base,
diff --git a/qemu-img.c b/qemu-img.c
index 3b11414..28efb4f 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1482,8 +1482,15 @@ static int img_convert(int argc, char **argv)
                    are present in both the output's and input's base images (no
                    need to copy them). */
                 if (out_baseimg) {
-                    if (!bdrv_is_allocated(bs[bs_i], sector_num - bs_offset,
-                                           n, &n1)) {
+                    ret = bdrv_is_allocated(bs[bs_i], sector_num - bs_offset,
+                                            n, &n1);
+                    if (ret < 0) {
+                        error_report("error while reading metadata for sector "
+                                     "%" PRId64 ": %s",
+                                     sector_num - bs_offset, strerror(-ret));
+                        goto out;
+                    }
+                    if (!ret) {
                         sector_num += n1;
                         continue;
                     }
@@ -2217,6 +2224,11 @@ static int img_rebase(int argc, char **argv)
 
             /* If the cluster is allocated, we don't need to take action */
             ret = bdrv_is_allocated(bs, sector, n, &n);
+            if (ret < 0) {
+                error_report("error while reading image metadata: %s",
+                             strerror(-ret));
+                goto out;
+            }
             if (ret) {
                 continue;
             }
diff --git a/qemu-io.c b/qemu-io.c
index 5045ff8..bdcce7f 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -1607,6 +1607,10 @@ static int alloc_f(int argc, char **argv)
     sector_num = offset >> 9;
     while (remaining) {
         ret = bdrv_is_allocated(bs, sector_num, remaining, &num);
+        if (ret < 0) {
+            printf("is_allocated failed: %s\n", strerror(-ret));
+            return 0;
+        }
         sector_num += num;
         remaining -= num;
         if (ret) {
-- 
1.7.1