From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38308) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fbYv6-0002dz-SO for qemu-devel@nongnu.org; Fri, 06 Jul 2018 18:09:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fbYv5-0005i9-Uf for qemu-devel@nongnu.org; Fri, 06 Jul 2018 18:09:40 -0400 References: <20180705073701.10558-1-famz@redhat.com> <20180705073701.10558-9-famz@redhat.com> From: Eric Blake Message-ID: Date: Fri, 6 Jul 2018 17:09:27 -0500 MIME-Version: 1.0 In-Reply-To: <20180705073701.10558-9-famz@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 8/9] block: Fix bdrv_co_truncate overlap check List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng , qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, Kevin Wolf , Max Reitz , Jeff Cody , John Snow , Stefan Hajnoczi On 07/05/2018 02:37 AM, Fam Zheng wrote: > If we are growing the image and potentially using preallocation for the > new area, we need to make sure that no write requests are made to the > "preallocated" area which [@old_size, @offset), not [@offset, offset * 2 s/which/which is/ > - @old_size). > > Signed-off-by: Fam Zheng > --- > block/io.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) Reviewed-by: Eric Blake > > diff --git a/block/io.c b/block/io.c > index d07849fa96..ed18eb0ca3 100644 > --- a/block/io.c > +++ b/block/io.c > @@ -3070,7 +3070,8 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, > } > > bdrv_inc_in_flight(bs); > - tracked_request_begin(&req, bs, offset, new_bytes, BDRV_TRACKED_TRUNCATE); > + tracked_request_begin(&req, bs, offset - new_bytes, new_bytes, > + BDRV_TRACKED_TRUNCATE); Is it any more legible to do s/offset - new_bytes/old_size/, since those are equivalent? > > /* If we are growing the image and potentially using preallocation for the > * new area, we need to make sure that no write requests are made to it > -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org