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[Qemu-devel] [PATCH] block: prevent multiwrite_merge from creating too l
From: |
Christoph Hellwig |
Subject: |
[Qemu-devel] [PATCH] block: prevent multiwrite_merge from creating too large iovecs |
Date: |
Tue, 19 Jan 2010 22:15:39 +0100 |
User-agent: |
Mutt/1.3.28i |
If we go over the maximum number of iovecs support by syscall we get
back EINVAL from the kernel which translate to I/O errors for the guest.
Signed-off-by: Christoph Hellwig <address@hidden>
Index: qemu/block.c
===================================================================
--- qemu.orig/block.c 2010-01-19 22:10:19.797003226 +0100
+++ qemu/block.c 2010-01-19 22:11:08.226005767 +0100
@@ -1711,6 +1711,10 @@ static int multiwrite_merge(BlockDriverS
merge = bs->drv->bdrv_merge_requests(bs, &reqs[outidx], &reqs[i]);
}
+ if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) {
+ merge = 0;
+ }
+
if (merge) {
size_t size;
QEMUIOVector *qiov = qemu_mallocz(sizeof(*qiov));