[PATCH 004 of 19] knfsd: lockd: introduce nsm_handle

NeilBrown
2006-09-01T04:39:33Z

From: Olaf Kirch <okir@suse.de>

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>

### Diffstat output
./fs/lockd/clntlock.c | 3 -
./fs/lockd/host.c | 121 ++++++++++++++++++++++++++++++++++++++----
./fs/lockd/mon.c | 14 +++-
./include/linux/lockd/lockd.h | 17 ++++-
4 files changed, 136 insertions(+), 19 deletions(-)

diff .prev/fs/lockd/clntlock.c ./fs/lockd/clntlock.c
--- .prev/fs/lockd/clntlock.c 2006-08-31 16:44:23.000000000 +1000
+++ ./fs/lockd/clntlock.c 2006-08-31 17:00:03.000000000 +1000
@@ -150,7 +150,8 @@ u32 nlmclnt_grant(const struct sockaddr_
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 .prev/fs/lockd/host.c ./fs/lockd/host.c
--- .prev/fs/lockd/host.c 2006-08-31 16:23:12.000000000 +1000
+++ ./fs/lockd/host.c 2006-08-31 17:00:03.000000000 +1000
@@ -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
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
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
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
}
}

- /* 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
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
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_read(&nsm->sm_count) == 1) {
+ down(&nsm_sema);
+ if (atomic_dec_and_test(&nsm->sm_count)) {
+ list_del(&nsm->sm_link);
+ kfree(nsm);
+ }
+ up(&nsm_sema);
+ }
+}

diff .prev/fs/lockd/mon.c ./fs/lockd/mon.c
--- .prev/fs/lockd/mon.c 2006-08-31 16:12:30.000000000 +1000
+++ ./fs/lockd/mon.c 2006-08-31 17:00:03.000000000 +1000
@@ -70,11 +70,14 @@ nsm_mon_unmon(struct nlm_host *host, u32
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 .prev/include/linux/lockd/lockd.h ./include/linux/lockd/lockd.h
--- .prev/include/linux/lockd/lockd.h 2006-08-31 16:23:12.000000000 +1000
+++ ./include/linux/lockd/lockd.h 2006-08-31 17:00:03.000000000 +1000
@@ -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 *);

/*