Re: [Qemu-devel] [PATCH 1/2] block: fix overlapping multiwrite requests

2014-07-29 Thread Stefan Hajnoczi
On Tue, Jul 29, 2014 at 1:46 PM, Fam Zheng wrote: > On Tue, 07/29 13:41, Stefan Hajnoczi wrote: >> When request A is a strict subset of request B: >> >> >> > > s/subset/superset/ ? Yes :)

Re: [Qemu-devel] [PATCH 1/2] block: fix overlapping multiwrite requests

2014-07-29 Thread Fam Zheng
On Tue, 07/29 13:41, Stefan Hajnoczi wrote: > When request A is a strict subset of request B: > > > s/subset/superset/ ? Fam

[Qemu-devel] [PATCH 1/2] block: fix overlapping multiwrite requests

2014-07-29 Thread Stefan Hajnoczi
When request A is a strict subset of request B: multiwrite_merge() merges them as follows: AA The tail of request A should have been included: AAAA This patch fixes data loss but this code path is probably rare. Since guests cannot assume ordering between in-f