[5/9] Don't allow multiwrites against a block device without underlying medium
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Message ID 1300272481-8744-6-git-send-email-kwolf@redhat.com
State New
Headers show

Commit Message

Kevin Wolf March 16, 2011, 10:47 a.m. 
From: Ryan Harper <ryanh@us.ibm.com>

If the block device has been closed, we no longer have a medium to submit
IO against, check for this before submitting io.  This prevents a segfault
further in the code where we dereference elements of the block driver.

Signed-off-by: Ryan Harper <ryanh@us.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

Patch
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diff --git a/block.c b/block.c
index 0559d83..c8e2f97 100644
--- a/block.c
+++ b/block.c
@@ -2398,6 +2398,14 @@  int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs)
     MultiwriteCB *mcb;
     int i;
 
+    /* don't submit writes if we don't have a medium */
+    if (bs->drv == NULL) {
+        for (i = 0; i < num_reqs; i++) {
+            reqs[i].error = -ENOMEDIUM;
+        }
+        return -1;
+    }
+
     if (num_reqs == 0) {
         return 0;
     }