qed: Handle failure for potentially large allocations

Some code in the block layer makes potentially huge allocations. Failure
is not completely unexpected there, so avoid aborting qemu and handle
out-of-memory situations gracefully.

This patch addresses the allocations in the qed block driver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>

block/qed-check.c

@@ -227,8 +227,11 @@ int qed_check(BDRVQEDState *s, BdrvCheckResult *result, bool fix)
     };
     int ret;
 
-    check.used_clusters = g_malloc0(((check.nclusters + 31) / 32) *
-                                       sizeof(check.used_clusters[0]));
+    check.used_clusters = g_try_malloc0(((check.nclusters + 31) / 32) *
+                                        sizeof(check.used_clusters[0]));
+    if (check.nclusters && check.used_clusters == NULL) {
+        return -ENOMEM;
+    }
 
     check.result->bfi.total_clusters =
         (s->header.image_size + s->header.cluster_size - 1) /

block/qed.c

@@ -1240,7 +1240,11 @@ static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len)
         struct iovec *iov = acb->qiov->iov;
 
         if (!iov->iov_base) {
-            iov->iov_base = qemu_blockalign(acb->common.bs, iov->iov_len);
+            iov->iov_base = qemu_try_blockalign(acb->common.bs, iov->iov_len);
+            if (iov->iov_base == NULL) {
+                qed_aio_complete(acb, -ENOMEM);
+                return;
+            }
             memset(iov->iov_base, 0, iov->iov_len);
         }
     }