block: fix overlapping multiwrite requests
When request A is a strict superset of request B:
AAAAAAAA
BBBB
multiwrite_merge() merges them as follows:
AABBBB
The tail of request A should have been included:
AABBBBAA
This patch fixes data loss but this code path is probably rare. Since
guests cannot assume ordering between in-flight requests, few
applications submit overlapping write requests.
Reported-by: Slava Pestov <sviatoslav.pestov@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
1 file changed
