From 0ad95472bf169a3501991f8f33f5147f792a8116 Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Wed, 23 Sep 2015 15:49:29 +0300 Subject: lockd: create NSM handles per net namespace Commit cb7323fffa85 ("lockd: create and use per-net NSM RPC clients on MON/UNMON requests") introduced per-net NSM RPC clients. Unfortunately this doesn't make any sense without per-net nsm_handle. E.g. the following scenario could happen Two hosts (X and Y) in different namespaces (A and B) share the same nsm struct. 1. nsm_monitor(host_X) called => NSM rpc client created, nsm->sm_monitored bit set. 2. nsm_mointor(host-Y) called => nsm->sm_monitored already set, we just exit. Thus in namespace B ln->nsm_clnt == NULL. 3. host X destroyed => nsm->sm_count decremented to 1 4. host Y destroyed => nsm_unmonitor() => nsm_mon_unmon() => NULL-ptr dereference of *ln->nsm_clnt So this could be fixed by making per-net nsm_handles list, instead of global. Thus different net namespaces will not be able share the same nsm_handle. Signed-off-by: Andrey Ryabinin Cc: Signed-off-by: J. Bruce Fields --- fs/lockd/svc.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/lockd/svc.c') diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c index d678bcc3cbcb..0dff13f41808 100644 --- a/fs/lockd/svc.c +++ b/fs/lockd/svc.c @@ -593,6 +593,7 @@ static int lockd_init_net(struct net *net) INIT_LIST_HEAD(&ln->lockd_manager.list); ln->lockd_manager.block_opens = false; spin_lock_init(&ln->nsm_clnt_lock); + INIT_LIST_HEAD(&ln->nsm_handles); return 0; } -- cgit v1.2.3-59-g8ed1b From 0d0f4aab4e4d290138a4ae7f2ef8469e48c9a669 Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Wed, 7 Oct 2015 14:39:55 +0300 Subject: lockd: get rid of reference-counted NSM RPC clients Currently we have reference-counted per-net NSM RPC client which created on the first monitor request and destroyed after the last unmonitor request. It's needed because RPC client need to know 'utsname()->nodename', but utsname() might be NULL when nsm_unmonitor() called. So instead of holding the rpc client we could just save nodename in struct nlm_host and pass it to the rpc_create(). Thus ther is no need in keeping rpc client until last unmonitor request. We could create separate RPC clients for each monitor/unmonitor requests. Signed-off-by: Andrey Ryabinin Signed-off-by: J. Bruce Fields --- fs/lockd/host.c | 1 + fs/lockd/mon.c | 89 ++++++++------------------------------------- fs/lockd/netns.h | 3 -- fs/lockd/svc.c | 1 - include/linux/lockd/lockd.h | 1 + 5 files changed, 17 insertions(+), 78 deletions(-) (limited to 'fs/lockd/svc.c') diff --git a/fs/lockd/host.c b/fs/lockd/host.c index b5f3c3ab0d5f..d716c9993a26 100644 --- a/fs/lockd/host.c +++ b/fs/lockd/host.c @@ -161,6 +161,7 @@ static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni, host->h_nsmhandle = nsm; host->h_addrbuf = nsm->sm_addrbuf; host->net = ni->net; + strlcpy(host->nodename, utsname()->nodename, sizeof(host->nodename)); out: return host; diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c index 6c05cd17e520..19166d4a8d31 100644 --- a/fs/lockd/mon.c +++ b/fs/lockd/mon.c @@ -42,7 +42,7 @@ struct nsm_args { u32 proc; char *mon_name; - char *nodename; + const char *nodename; }; struct nsm_res { @@ -86,69 +86,18 @@ static struct rpc_clnt *nsm_create(struct net *net, const char *nodename) return rpc_create(&args); } -static struct rpc_clnt *nsm_client_set(struct lockd_net *ln, - struct rpc_clnt *clnt) -{ - spin_lock(&ln->nsm_clnt_lock); - if (ln->nsm_users == 0) { - if (clnt == NULL) - goto out; - ln->nsm_clnt = clnt; - } - clnt = ln->nsm_clnt; - ln->nsm_users++; -out: - spin_unlock(&ln->nsm_clnt_lock); - return clnt; -} - -static struct rpc_clnt *nsm_client_get(struct net *net, const char *nodename) -{ - struct rpc_clnt *clnt, *new; - struct lockd_net *ln = net_generic(net, lockd_net_id); - - clnt = nsm_client_set(ln, NULL); - if (clnt != NULL) - goto out; - - clnt = new = nsm_create(net, nodename); - if (IS_ERR(clnt)) - goto out; - - clnt = nsm_client_set(ln, new); - if (clnt != new) - rpc_shutdown_client(new); -out: - return clnt; -} - -static void nsm_client_put(struct net *net) -{ - struct lockd_net *ln = net_generic(net, lockd_net_id); - struct rpc_clnt *clnt = NULL; - - spin_lock(&ln->nsm_clnt_lock); - ln->nsm_users--; - if (ln->nsm_users == 0) { - clnt = ln->nsm_clnt; - ln->nsm_clnt = NULL; - } - spin_unlock(&ln->nsm_clnt_lock); - if (clnt != NULL) - rpc_shutdown_client(clnt); -} - static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res, - struct rpc_clnt *clnt) + const struct nlm_host *host) { int status; + struct rpc_clnt *clnt; struct nsm_args args = { .priv = &nsm->sm_priv, .prog = NLM_PROGRAM, .vers = 3, .proc = NLMPROC_NSM_NOTIFY, .mon_name = nsm->sm_mon_name, - .nodename = clnt->cl_nodename, + .nodename = host->nodename, }; struct rpc_message msg = { .rpc_argp = &args, @@ -157,6 +106,13 @@ static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res, memset(res, 0, sizeof(*res)); + clnt = nsm_create(host->net, host->nodename); + if (IS_ERR(clnt)) { + dprintk("lockd: failed to create NSM upcall transport, " + "status=%ld, net=%p\n", PTR_ERR(clnt), host->net); + return PTR_ERR(clnt); + } + msg.rpc_proc = &clnt->cl_procinfo[proc]; status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); if (status == -ECONNREFUSED) { @@ -170,6 +126,8 @@ static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res, status); else status = 0; + + rpc_shutdown_client(clnt); return status; } @@ -189,32 +147,19 @@ int nsm_monitor(const struct nlm_host *host) struct nsm_handle *nsm = host->h_nsmhandle; struct nsm_res res; int status; - struct rpc_clnt *clnt; - const char *nodename = NULL; dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); if (nsm->sm_monitored) return 0; - if (host->h_rpcclnt) - nodename = host->h_rpcclnt->cl_nodename; - /* * Choose whether to record the caller_name or IP address of * this peer in the local rpc.statd's database. */ nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; - clnt = nsm_client_get(host->net, nodename); - if (IS_ERR(clnt)) { - status = PTR_ERR(clnt); - dprintk("lockd: failed to create NSM upcall transport, " - "status=%d, net=%p\n", status, host->net); - return status; - } - - status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, clnt); + status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, host); if (unlikely(res.status != 0)) status = -EIO; if (unlikely(status < 0)) { @@ -246,11 +191,9 @@ void nsm_unmonitor(const struct nlm_host *host) if (atomic_read(&nsm->sm_count) == 1 && nsm->sm_monitored && !nsm->sm_sticky) { - struct lockd_net *ln = net_generic(host->net, lockd_net_id); - dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); - status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, ln->nsm_clnt); + status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, host); if (res.status != 0) status = -EIO; if (status < 0) @@ -258,8 +201,6 @@ void nsm_unmonitor(const struct nlm_host *host) nsm->sm_name); else nsm->sm_monitored = 0; - - nsm_client_put(host->net); } } diff --git a/fs/lockd/netns.h b/fs/lockd/netns.h index 89fe011b1335..5426189406c1 100644 --- a/fs/lockd/netns.h +++ b/fs/lockd/netns.h @@ -12,9 +12,6 @@ struct lockd_net { struct delayed_work grace_period_end; struct lock_manager lockd_manager; - spinlock_t nsm_clnt_lock; - unsigned int nsm_users; - struct rpc_clnt *nsm_clnt; struct list_head nsm_handles; }; diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c index 0dff13f41808..5f31ebd96c06 100644 --- a/fs/lockd/svc.c +++ b/fs/lockd/svc.c @@ -592,7 +592,6 @@ static int lockd_init_net(struct net *net) INIT_DELAYED_WORK(&ln->grace_period_end, grace_ender); INIT_LIST_HEAD(&ln->lockd_manager.list); ln->lockd_manager.block_opens = false; - spin_lock_init(&ln->nsm_clnt_lock); INIT_LIST_HEAD(&ln->nsm_handles); return 0; } diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h index fd3b65bf51b5..c15373894a42 100644 --- a/include/linux/lockd/lockd.h +++ b/include/linux/lockd/lockd.h @@ -68,6 +68,7 @@ struct nlm_host { struct nsm_handle *h_nsmhandle; /* NSM status handle */ char *h_addrbuf; /* address eyecatcher */ struct net *net; /* host net */ + char nodename[UNX_MAXNODENAME + 1]; }; /* -- cgit v1.2.3-59-g8ed1b