Re: [Nbd] [PATCH] nbd: Zero from and len fields in NBD_CMD_DISCONNECT.
- To: Hani Benhabiles <kroosec@...17...>
- Cc: "nbd-general@lists.sourceforge.net" <nbd-general@lists.sourceforge.net>, kernel list <linux-kernel@...25...>
- Subject: Re: [Nbd] [PATCH] nbd: Zero from and len fields in NBD_CMD_DISCONNECT.
- From: Paul Clements <paul.clements@...856...>
- Date: Sun, 25 May 2014 14:11:13 -0400
- Message-id: <CAECXXi69w4HNUbZbb3JWxwZkqnyQf=dmm57UJEHOY0Xv6B4pEA@...18...>
- In-reply-to: <20140525101840.GA3588@...1599...>
- References: <1400283807-27930-1-git-send-email-kroosec@...17...> <CAECXXi4_RJ-yk8Ct=sPPe-pq=shdU-4cKvRTT3yNvsoY42-8_Q@...18...> <20140518091113.GA3770@...1599...> <20140525101840.GA3588@...1599...>
On Sun, May 25, 2014 at 6:18 AM, Hani Benhabiles <kroosec@...17...> wrote:
> On Sun, May 18, 2014 at 10:11:13AM +0100, Hani Benhabiles wrote:
>> On Fri, May 16, 2014 at 10:56:33PM -0400, Paul Clements wrote:
>> > Agreed. But better yet, the request structure should just be zeroed when
>> > it's allocated.
>> >
>>
>> It is already initialized in __nbd_ioctl() with the blk_rq_init() call which
>> sets the __sector value to -1 (which is 0xfffffffffffffe00 after the left shifts.)
>>
>> This is the only (non-ugly / non-intrusive) way to do it afaict.
>>
>
> Ping!
>
> Anything blocking this patch ?
It's cleaner to just zero the struct and get rid of the conditional
zeroing of specific fields. I'll prepare a patch in the next few days.
Thanks,
Paul
>> > On Fri, May 16, 2014 at 7:43 PM, Hani Benhabiles <kroosec@...17...> wrote:
>> >
>> > > Len field is already set to zero, but not the from field which is sent as
>> > > 0xfffffffffffffe00. This makes no sense, and may cause confuse server
>> > > implementations doing sanity checks (qemu-nbd is an example.)
>> > >
>> > > Signed-off-by: Hani Benhabiles <hani@...1598...>
>> > > ---
>> > > drivers/block/nbd.c | 2 +-
>> > > 1 file changed, 1 insertion(+), 1 deletion(-)
>> > >
>> > > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
>> > > index 3a70ea2..657bdac 100644
>> > > --- a/drivers/block/nbd.c
>> > > +++ b/drivers/block/nbd.c
>> > > @@ -246,7 +246,7 @@ static int nbd_send_req(struct nbd_device *nbd, struct
>> > > request *req)
>> > > request.magic = htonl(NBD_REQUEST_MAGIC);
>> > > request.type = htonl(nbd_cmd(req));
>> > >
>> > > - if (nbd_cmd(req) == NBD_CMD_FLUSH) {
>> > > + if (nbd_cmd(req) == NBD_CMD_FLUSH || nbd_cmd(req) == NBD_CMD_DISC)
>> > > {
>> > > /* Other values are reserved for FLUSH requests. */
>> > > request.from = 0;
>> > > request.len = 0;
>> > > --
>> > > 1.8.3.2
>> > >
>> > >
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