block: expect errors from bdrv_co_is_allocated

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>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit d663640c04f2aab810915c556390211d75457704)

Conflicts:

	block/cow.c

*modified to avoid dependency on upstream's e641c1e8

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/block.c b/block.c
index d5ce8d39e423b7400bba6c5e92460d8a4ae797b3..8ce8b91f00cd0d33918b56637e9bc83da400ebc6 100644 (file)
--- a/block.c
+++ b/block.c
@@ -1803,8 +1803,11 @@ 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 1cc2e89c7cd01a62223cdbca5c4d5e47e12c71d6..e1b73d63ad3f651099e4479996f8515cbb929af2 100644 (file)
--- a/block/cow.c
+++ b/block/cow.c
@@ -189,7 +189,11 @@ static int coroutine_fn cow_read(BlockDriverState *bs, int64_t sector_num,
     int ret, n;
 
     while (nb_sectors > 0) {
-        if (bdrv_co_is_allocated(bs, sector_num, nb_sectors, &n)) {
+        ret = bdrv_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 3376901bd7b274c944ed88ec26873c6fc3ad61c6..7f7282e0c40a88de0b1d14d204ca2164dc94ea94 100644 (file)
--- 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 7fe9e486bf3f9c6b2b2c08669dd23b4c29709206..4e8d177fdc1b0e0278d8327a1c553991ce308a12 100644 (file)
--- 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_co_is_allocated_above(bs->backing_hd, base,

diff --git a/qemu-img.c b/qemu-img.c
index b9a848db74de8c77e8a009669ac72fe048bc71cc..b01998b04909caa19dce40a209b09f370d20283d 100644 (file)
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1485,8 +1485,15 @@ 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;
                     }
@@ -2076,6 +2083,11 @@ 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-cmds.c b/qemu-io-cmds.c
index ffbcf31cfc6389e7b615bfc9529dc3e9629220f8..ffe48adfba953109dc47ed2ec4e836cc6caf0a42 100644 (file)
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -1829,6 +1829,10 @@ static int alloc_f(BlockDriverState *bs, 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) {