[PATCH] knfsd: lockd: introduce nsm_handle

This patch introduces the nsm_handle, which is shared by all nlm_host objects
referring to the same client.

With this patch applied, all nlm_hosts from the same address will share the
same nsm_handle.  A future patch will add sharing by name.

Note: this patch changes h_name so that it is no longer guaranteed to be an IP
address of the host.  When the host represents an NFS server, h_name will be
the name passed in the mount call.  When the host represents a client, h_name
will be the name presented in the lock request received from the client.  A
h_name is only used for printing informational messages, this change should
not be significant.

Signed-off-by: Olaf Kirch <okir@suse.de>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
index 87e1d03..54e63dd 100644 (file)
--- a/fs/lockd/clntlock.c
+++ b/fs/lockd/clntlock.c
@@ -150,7 +150,8 @@ u32 nlmclnt_grant(const struct sockaddr_in *addr, const struct nlm_lock *lock)
 static void nlmclnt_prepare_reclaim(struct nlm_host *host)
 {
        down_write(&host->h_rwsem);
-       host->h_monitored = 0;
+       if (host->h_nsmhandle)
+               host->h_nsmhandle->sm_monitored = 0;
        host->h_state++;
        host->h_nextrebind = 0;
        nlm_rebind_host(host);

diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index 481ce7e..0bf4afb 100644 (file)
--- a/fs/lockd/host.c
+++ b/fs/lockd/host.c
@@ -34,6 +34,8 @@ static DEFINE_MUTEX(nlm_host_mutex);
 
 
 static void                    nlm_gc_hosts(void);
+static struct nsm_handle *     __nsm_find(const struct sockaddr_in *,
+                                       const char *, int, int);
 
 /*
  * Find an NLM server handle in the cache. If there is none, create it.
@@ -68,7 +70,7 @@ nlm_lookup_host(int server, const struct sockaddr_in *sin,
                                        int hostname_len)
 {
        struct nlm_host *host, **hp;
-       u32             addr;
+       struct nsm_handle *nsm = NULL;
        int             hash;
 
        dprintk("lockd: nlm_lookup_host(%u.%u.%u.%u, p=%d, v=%d, my role=%s, name=%.*s)\n",
@@ -86,7 +88,21 @@ nlm_lookup_host(int server, const struct sockaddr_in *sin,
        if (time_after_eq(jiffies, next_gc))
                nlm_gc_hosts();
 
+       /* We may keep several nlm_host objects for a peer, because each
+        * nlm_host is identified by
+        * (address, protocol, version, server/client)
+        * We could probably simplify this a little by putting all those
+        * different NLM rpc_clients into one single nlm_host object.
+        * This would allow us to have one nlm_host per address.
+        */
        for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
+               if (!nlm_cmp_addr(&host->h_addr, sin))
+                       continue;
+
+               /* See if we have an NSM handle for this client */
+               if (!nsm && (nsm = host->h_nsmhandle) != 0)
+                       atomic_inc(&nsm->sm_count);
+
                if (host->h_proto != proto)
                        continue;
                if (host->h_version != version)
@@ -94,7 +110,7 @@ nlm_lookup_host(int server, const struct sockaddr_in *sin,
                if (host->h_server != server)
                        continue;
 
-               if (nlm_cmp_addr(&host->h_addr, sin)) {
+               {
                        if (hp != nlm_hosts + hash) {
                                *hp = host->h_next;
                                host->h_next = nlm_hosts[hash];
@@ -106,16 +122,18 @@ nlm_lookup_host(int server, const struct sockaddr_in *sin,
                }
        }
 
-       /* Ooops, no host found, create it */
-       dprintk("lockd: creating host entry\n");
+       /* Sadly, the host isn't in our hash table yet. See if
+        * we have an NSM handle for it. If not, create one.
+        */
+       if (!nsm && !(nsm = nsm_find(sin, hostname, hostname_len)))
+               goto out;
 
        host = kzalloc(sizeof(*host), GFP_KERNEL);
-       if (!host)
-               goto nohost;
-
-       addr = sin->sin_addr.s_addr;
-       sprintf(host->h_name, "%u.%u.%u.%u", NIPQUAD(addr));
-
+       if (!host) {
+               nsm_release(nsm);
+               goto out;
+       }
+       host->h_name       = nsm->sm_name;
        host->h_addr       = *sin;
        host->h_addr.sin_port = 0;      /* ouch! */
        host->h_version    = version;
@@ -129,6 +147,7 @@ nlm_lookup_host(int server, const struct sockaddr_in *sin,
        init_rwsem(&host->h_rwsem);
        host->h_state      = 0;                 /* pseudo NSM state */
        host->h_nsmstate   = 0;                 /* real NSM state */
+       host->h_nsmhandle  = nsm;
        host->h_server     = server;
        host->h_next       = nlm_hosts[hash];
        nlm_hosts[hash]    = host;
@@ -140,7 +159,7 @@ nlm_lookup_host(int server, const struct sockaddr_in *sin,
        if (++nrhosts > NLM_HOST_MAX)
                next_gc = 0;
 
-nohost:
+out:
        mutex_unlock(&nlm_host_mutex);
        return host;
 }
@@ -393,3 +412,83 @@ nlm_gc_hosts(void)
        next_gc = jiffies + NLM_HOST_COLLECT;
 }
 
+
+/*
+ * Manage NSM handles
+ */
+static LIST_HEAD(nsm_handles);
+static DECLARE_MUTEX(nsm_sema);
+
+static struct nsm_handle *
+__nsm_find(const struct sockaddr_in *sin,
+               const char *hostname, int hostname_len,
+               int create)
+{
+       struct nsm_handle *nsm = NULL;
+       struct list_head *pos;
+
+       if (!sin)
+               return NULL;
+
+       if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
+               if (printk_ratelimit()) {
+                       printk(KERN_WARNING "Invalid hostname \"%.*s\" "
+                                           "in NFS lock request\n",
+                               hostname_len, hostname);
+               }
+               return NULL;
+       }
+
+       down(&nsm_sema);
+       list_for_each(pos, &nsm_handles) {
+               nsm = list_entry(pos, struct nsm_handle, sm_link);
+
+               if (!nlm_cmp_addr(&nsm->sm_addr, sin))
+                       continue;
+               atomic_inc(&nsm->sm_count);
+               goto out;
+       }
+
+       if (!create) {
+               nsm = NULL;
+               goto out;
+       }
+
+       nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
+       if (nsm != NULL) {
+               nsm->sm_addr = *sin;
+               nsm->sm_name = (char *) (nsm + 1);
+               memcpy(nsm->sm_name, hostname, hostname_len);
+               nsm->sm_name[hostname_len] = '\0';
+               atomic_set(&nsm->sm_count, 1);
+
+               list_add(&nsm->sm_link, &nsm_handles);
+       }
+
+out:   up(&nsm_sema);
+       return nsm;
+}
+
+struct nsm_handle *
+nsm_find(const struct sockaddr_in *sin, const char *hostname, int hostname_len)
+{
+       return __nsm_find(sin, hostname, hostname_len, 1);
+}
+
+/*
+ * Release an NSM handle
+ */
+void
+nsm_release(struct nsm_handle *nsm)
+{
+       if (!nsm)
+               return;
+       if (atomic_dec_and_test(&nsm->sm_count)) {
+               down(&nsm_sema);
+               if (atomic_read(&nsm->sm_count) == 0) {
+                       list_del(&nsm->sm_link);
+                       kfree(nsm);
+               }
+               up(&nsm_sema);
+       }
+}

diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index e02a1a4..e279814 100644 (file)
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -70,11 +70,14 @@ nsm_mon_unmon(struct nlm_host *host, u32 proc, struct nsm_res *res)
 int
 nsm_monitor(struct nlm_host *host)
 {
+       struct nsm_handle *nsm = host->h_nsmhandle;
        struct nsm_res  res;
        int             status;
 
        dprintk("lockd: nsm_monitor(%s)\n", host->h_name);
-       if (host->h_monitored)
+       BUG_ON(nsm == NULL);
+
+       if (nsm->sm_monitored)
                return 0;
 
        status = nsm_mon_unmon(host, SM_MON, &res);
@@ -82,7 +85,7 @@ nsm_monitor(struct nlm_host *host)
        if (status < 0 || res.status != 0)
                printk(KERN_NOTICE "lockd: cannot monitor %s\n", host->h_name);
        else
-               host->h_monitored = 1;
+               nsm->sm_monitored = 1;
        return status;
 }
 
@@ -92,19 +95,22 @@ nsm_monitor(struct nlm_host *host)
 int
 nsm_unmonitor(struct nlm_host *host)
 {
+       struct nsm_handle *nsm = host->h_nsmhandle;
        struct nsm_res  res;
        int             status = 0;
 
        dprintk("lockd: nsm_unmonitor(%s)\n", host->h_name);
-       if (!host->h_monitored)
+       if (nsm == NULL)
                return 0;
-       host->h_monitored = 0;
+       host->h_nsmhandle = NULL;
 
        if (!host->h_killed) {
                status = nsm_mon_unmon(host, SM_UNMON, &res);
                if (status < 0)
                        printk(KERN_NOTICE "lockd: cannot unmonitor %s\n", host->h_name);
+               nsm->sm_monitored = 0;
        }
+       nsm_release(nsm);
        return status;
 }
 

diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index 0f9b236..ab2ffc8 100644 (file)
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -40,14 +40,13 @@ struct nlm_host {
        struct nlm_host *       h_next;         /* linked list (hash table) */
        struct sockaddr_in      h_addr;         /* peer address */
        struct rpc_clnt *       h_rpcclnt;      /* RPC client to talk to peer */
-       char                    h_name[20];     /* remote hostname */
+       char *                  h_name;         /* remote hostname */
        u32                     h_version;      /* interface version */
        unsigned short          h_proto;        /* transport proto */
        unsigned short          h_reclaiming : 1,
                                h_server     : 1, /* server side, not client side */
                                h_inuse      : 1,
-                               h_killed     : 1,
-                               h_monitored  : 1;
+                               h_killed     : 1;
        wait_queue_head_t       h_gracewait;    /* wait while reclaiming */
        struct rw_semaphore     h_rwsem;        /* Reboot recovery lock */
        u32                     h_state;        /* pseudo-state counter */
@@ -61,6 +60,16 @@ struct nlm_host {
        spinlock_t              h_lock;
        struct list_head        h_granted;      /* Locks in GRANTED state */
        struct list_head        h_reclaim;      /* Locks in RECLAIM state */
+       struct nsm_handle *     h_nsmhandle;    /* NSM status handle */
+};
+
+struct nsm_handle {
+       struct list_head        sm_link;
+       atomic_t                sm_count;
+       char *                  sm_name;
+       struct sockaddr_in      sm_addr;
+       unsigned int            sm_monitored : 1,
+                               sm_sticky : 1;  /* don't unmonitor */
 };
 
 /*
@@ -171,6 +180,8 @@ void                  nlm_release_host(struct nlm_host *);
 void             nlm_shutdown_hosts(void);
 extern struct nlm_host *nlm_find_client(void);
 extern void      nlm_host_rebooted(const struct sockaddr_in *, const struct nlm_reboot *);
+struct nsm_handle *nsm_find(const struct sockaddr_in *, const char *, int);
+void             nsm_release(struct nsm_handle *);
 
 
 /*