From: Trond Myklebust Subject: Re: [PATCH 016 of 19] knfsd: match GRANTED_RES replies using cookies Date: Fri, 01 Sep 2006 12:03:38 -0400 Message-ID: <1157126618.5632.52.camel@localhost> References: <20060901141639.27206.patches@notabene> <1060901043932.27641@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Andrew Morton , Olaf Kirch , nfs@lists.sourceforge.net, linux-kernel@vger.kernel.org Return-path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list2-new.sourceforge.net with esmtp (Exim 4.43) id 1GJBUp-0007sF-Vk for nfs@lists.sourceforge.net; Fri, 01 Sep 2006 09:03:57 -0700 Received: from pat.uio.no ([129.240.10.4]) by mail.sourceforge.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.44) id 1GJBUp-0001cy-SI for nfs@lists.sourceforge.net; Fri, 01 Sep 2006 09:03:56 -0700 To: NeilBrown In-Reply-To: <1060901043932.27641@suse.de> List-Id: "Discussion of NFS under Linux development, interoperability, and testing." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: nfs-bounces@lists.sourceforge.net Errors-To: nfs-bounces@lists.sourceforge.net On Fri, 2006-09-01 at 14:39 +1000, NeilBrown wrote: > From: Olaf Kirch > > When we send a GRANTED_MSG call, we current copy the NLM cookie > provided in the original LOCK call - because in 1996, some broken > clients seemed to rely on this bug. However, this means the cookies > are not unique, so that when the client's GRANTED_RES message comes > back, we cannot simply match it based on the cookie, but have to > use the client's IP address in addition. Which breaks when you have > a multi-homed NFS client. > > The X/Open spec explicitly mentions that clients should not expect the > same cookie; so one may hope that any clients that were broken in 1996 > have either been fixed or rendered obsolete. Vetoed. The reason why we need the client's IP address as an argument for nlmsvc_find_block() is 'cos the cookie value is unique to the _client_ only. IOW: when we go searching a global list of blocks for a given cookie value that was sent to us by a given client, then we want to know that we're only searching through that particular client's blocks. A better way, BTW, would be to get rid of the global list nlm_blocked, and just move the list of blocks into a field in the nlm_host for each client. > Signed-off-by: Olaf Kirch > Signed-off-by: Neil Brown > > ### Diffstat output > ./fs/lockd/svc4proc.c | 2 +- > ./fs/lockd/svclock.c | 24 +++++++++++++----------- > ./fs/lockd/svcproc.c | 2 +- > ./include/linux/lockd/lockd.h | 2 +- > 4 files changed, 16 insertions(+), 14 deletions(-) > > diff .prev/fs/lockd/svc4proc.c ./fs/lockd/svc4proc.c > --- .prev/fs/lockd/svc4proc.c 2006-09-01 12:11:01.000000000 +1000 > +++ ./fs/lockd/svc4proc.c 2006-09-01 12:17:21.000000000 +1000 > @@ -455,7 +455,7 @@ nlm4svc_proc_granted_res(struct svc_rqst > > dprintk("lockd: GRANTED_RES called\n"); > > - nlmsvc_grant_reply(rqstp, &argp->cookie, argp->status); > + nlmsvc_grant_reply(&argp->cookie, argp->status); > return rpc_success; > } > > > diff .prev/fs/lockd/svclock.c ./fs/lockd/svclock.c > --- .prev/fs/lockd/svclock.c 2006-09-01 12:11:01.000000000 +1000 > +++ ./fs/lockd/svclock.c 2006-09-01 12:17:21.000000000 +1000 > @@ -139,19 +139,19 @@ static inline int nlm_cookie_match(struc > * Find a block with a given NLM cookie. > */ > static inline struct nlm_block * > -nlmsvc_find_block(struct nlm_cookie *cookie, struct sockaddr_in *sin) > +nlmsvc_find_block(struct nlm_cookie *cookie) > { > struct nlm_block *block; > > list_for_each_entry(block, &nlm_blocked, b_list) { > - if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie) > - && nlm_cmp_addr(sin, &block->b_host->h_addr)) > + if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie)) > goto found; > } > > return NULL; > > found: > + dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie), block); > kref_get(&block->b_count); > return block; > } > @@ -165,6 +165,11 @@ found: > * request, but (as I found out later) that's because some implementations > * do just this. Never mind the standards comittees, they support our > * logging industries. > + * > + * 10 years later: I hope we can safely ignore these old and broken > + * clients by now. Let's fix this so we can uniquely identify an incoming > + * GRANTED_RES message by cookie, without having to rely on the client's IP > + * address. --okir > */ > static inline struct nlm_block * > nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file, > @@ -197,7 +202,7 @@ nlmsvc_create_block(struct svc_rqst *rqs > /* Set notifier function for VFS, and init args */ > call->a_args.lock.fl.fl_flags |= FL_SLEEP; > call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; > - call->a_args.cookie = *cookie; /* see above */ > + nlmclnt_next_cookie(&call->a_args.cookie); > > dprintk("lockd: created block %p...\n", block); > > @@ -640,17 +645,14 @@ static const struct rpc_call_ops nlmsvc_ > * block. > */ > void > -nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status) > +nlmsvc_grant_reply(struct nlm_cookie *cookie, u32 status) > { > struct nlm_block *block; > - struct nlm_file *file; > > - dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", > - *(unsigned int *)(cookie->data), > - ntohl(rqstp->rq_addr.sin_addr.s_addr), status); > - if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr))) > + dprintk("grant_reply: looking for cookie %x, s=%d \n", > + *(unsigned int *)(cookie->data), status); > + if (!(block = nlmsvc_find_block(cookie))) > return; > - file = block->b_file; > > if (block) { > if (status == NLM_LCK_DENIED_GRACE_PERIOD) { > > diff .prev/fs/lockd/svcproc.c ./fs/lockd/svcproc.c > --- .prev/fs/lockd/svcproc.c 2006-09-01 12:11:01.000000000 +1000 > +++ ./fs/lockd/svcproc.c 2006-09-01 12:17:21.000000000 +1000 > @@ -484,7 +484,7 @@ nlmsvc_proc_granted_res(struct svc_rqst > > dprintk("lockd: GRANTED_RES called\n"); > > - nlmsvc_grant_reply(rqstp, &argp->cookie, argp->status); > + nlmsvc_grant_reply(&argp->cookie, argp->status); > return rpc_success; > } > > > diff .prev/include/linux/lockd/lockd.h ./include/linux/lockd/lockd.h > --- .prev/include/linux/lockd/lockd.h 2006-09-01 12:17:03.000000000 +1000 > +++ ./include/linux/lockd/lockd.h 2006-09-01 12:17:21.000000000 +1000 > @@ -193,7 +193,7 @@ u32 nlmsvc_cancel_blocked(struct nlm_ > unsigned long nlmsvc_retry_blocked(void); > void nlmsvc_traverse_blocks(struct nlm_host *, struct nlm_file *, > nlm_host_match_fn_t match); > -void nlmsvc_grant_reply(struct svc_rqst *, struct nlm_cookie *, u32); > +void nlmsvc_grant_reply(struct nlm_cookie *, u32); > > /* > * File handling for the server personality > > ------------------------------------------------------------------------- > Using Tomcat but need to do more? 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