autofs-5.0.9 - amd lookup fix host mount naming

From: Ian Kent <raven@themaw.net>

Currently the amd host mount type assumes the lookup name is

the host name for the host mount but amd uses ${rhost} for

this.

This introduces the possibility of multiple concurrent mount

requests since constructing a mount tree that isn't under the

lookup name can't take advantage of the kernel queuing other

concurrent lookups while the mount tree is constructed.

---

 daemon/lookup.c     |   20 +++++++++++++----

 modules/parse_amd.c |   61 ++++++++++++++++++++++++++++++++++++++++++++++++++--

 modules/parse_sun.c |   22 +++++++++++-------

 3 files changed, 89 insertions(+), 14 deletions(-)

--- autofs-5.0.7.orig/daemon/lookup.c

+++ autofs-5.0.7/daemon/lookup.c

@@ -815,7 +815,8 @@ static int lookup_amd_instance(struct au

 	m_key = malloc(strlen(ap->path) + strlen(me->multi->key) + 1);

 	if (!m_key) {

-		error(ap->logopt, "failed to allocate storage for search key");

+		error(ap->logopt,

+		     "failed to allocate storage for search key");

 		return NSS_STATUS_UNKNOWN;

 	}

@@ -823,12 +824,12 @@ static int lookup_amd_instance(struct au

 	strcat(m_key, "/");

 	strcat(m_key, me->multi->key);

 	entry = master_find_amdmount(ap, m_key);

+	free(m_key);

+

 	if (!entry) {

 		error(ap->logopt, "expected amd mount entry not found");

-		free(m_key);

 		return NSS_STATUS_UNKNOWN;

 	}

-	free(m_key);

 	if (strcmp(entry->type, "host")) {

 		error(ap->logopt, "unexpected map type %s", entry->type);

@@ -843,6 +844,17 @@ static int lookup_amd_instance(struct au

 	}

 	instance = master_find_source_instance(map, "hosts", "sun", argc, pargv);

+	/* If this is an nss map instance it may have an amd host map sub instance */

+	if (!instance && map->instance) {

+		struct map_source *next = map->instance;

+		while (next) {

+			instance = master_find_source_instance(next,

+						"hosts", "sun", argc, pargv);

+			if (instance)

+				break;

+			next = next->next;

+		}

+	}

 	if (!instance) {

 		error(ap->logopt, "expected hosts map instance not found");

 		return NSS_STATUS_UNKNOWN;

@@ -1174,7 +1186,6 @@ int lookup_nss_mount(struct autofs_point

 	}

 	if (ap->state != ST_INIT)

 		send_map_update_request(ap);

-	pthread_cleanup_pop(1);

 	/*

 	 * The last source lookup will return NSS_STATUS_NOTFOUND if the

@@ -1183,6 +1194,7 @@ int lookup_nss_mount(struct autofs_point

 	 */

 	if (result == NSS_STATUS_NOTFOUND || result == NSS_STATUS_UNAVAIL)

 		update_negative_cache(ap, source, name);

+	pthread_cleanup_pop(1);

 	return !result;

 }

--- autofs-5.0.7.orig/modules/parse_amd.c

+++ autofs-5.0.7/modules/parse_amd.c

@@ -1068,6 +1068,23 @@ static int do_nfsl_mount(struct autofs_p

 	return do_link_mount(ap, name, entry, flags);

 }

+static int wait_for_expire(struct autofs_point *ap)

+{

+	int ret = 1;

+

+	st_wait_task(ap, ST_EXPIRE, 0);

+

+	st_mutex_lock();

+	if (ap->state != ST_SHUTDOWN &&

+	    ap->state != ST_SHUTDOWN_PENDING &&

+	    ap->state != ST_SHUTDOWN_FORCE) {

+		ret = 0;

+	}

+	st_mutex_unlock();

+

+	return ret;

+}

+

 static int do_host_mount(struct autofs_point *ap, const char *name,

 			 struct amd_entry *entry, struct map_source *source,

 			 unsigned int flags)

@@ -1080,6 +1097,36 @@ static int do_host_mount(struct autofs_p

 	int argc = 0;

 	int ret = 1;

+	/*

+	 * If the mount point name isn't the same as the host name

+	 * then we need to symlink to it after the mount. Attempt

+	 * the allocation and set entry->path to the base location

+	 * of the hosts mount tree so we can find it in

+	 * lookup_nss_mount() later.

+	 */

+	if (strcmp(name, entry->rhost)) {

+		char *target;

+		size_t len = strlen(ap->path) + strlen(entry->rhost) + 2;

+		target = malloc(len);

+		if (!target) {

+			warn(ap->logopt, MODPREFIX

+			     "failed to alloc target to hosts mount base");

+			goto out;

+		}

+		strcpy(target, ap->path);

+		strcat(target, "/");

+		strcat(target, entry->rhost);

+		if (entry->path)

+			free(entry->path);

+		entry->path = target;

+		/*

+		 * Wait for any expire before racing to mount the

+		 * export tree or bail out if we're shutting down.

+		*/

+		if (!wait_for_expire(ap))

+			goto out;

+	}

+

 	if (entry->opts) {

 		argv[0] = entry->opts;

 		argv[1] = NULL;

@@ -1095,7 +1142,8 @@ static int do_host_mount(struct autofs_p

 		goto out;

 	}

-	instance = master_find_source_instance(source, "hosts", "sun", argc, pargv);

+	instance = master_find_source_instance(source,

+					 "hosts", "sun", argc, pargv);

 	if (!instance) {

 		instance = master_add_source_instance(source,

 				 "hosts", "sun", time(NULL), argc, pargv);

@@ -1119,7 +1167,16 @@ static int do_host_mount(struct autofs_p

 	master_source_current_wait(ap->entry);

 	ap->entry->current = source;

-	ret = lookup->lookup_mount(ap, name, strlen(name), lookup->context);

+	ret = lookup->lookup_mount(ap, entry->rhost,

+				   strlen(entry->rhost), lookup->context);

+

+	if (!strcmp(name, entry->rhost))

+		goto out;

+

+	if (do_mount(ap, ap->path,

+		     name, strlen(name), entry->path, "bind", "symlink"))

+		warn(ap->logopt, MODPREFIX

+		     "failed to create symlink to hosts mount base");

 out:

 	return ret;

 }

--- autofs-5.0.7.orig/modules/parse_sun.c

+++ autofs-5.0.7/modules/parse_sun.c

@@ -1343,26 +1343,32 @@ int parse_mount(struct autofs_point *ap,

 			strcat(m_root, name);

 		}

+		pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cur_state);

 		cache_readlock(mc);

 		me = cache_lookup_distinct(mc, name);

-		if (me) {

-			/* So we know we're the multi-mount root */

-			if (!me->multi)

-				me->multi = me;

-		}

-

 		if (!me) {

 			free(options);

 			cache_unlock(mc);

+			pthread_setcancelstate(cur_state, NULL);

 			error(ap->logopt,

 			      MODPREFIX "can't find multi root %s", name);

 			return 1;

 		}

+		cache_multi_writelock(me);

+		/* Someone beat us to it, return success */

+		if (me->multi) {

+			free(options);

+			cache_multi_unlock(me);

+			cache_unlock(mc);

+			pthread_setcancelstate(cur_state, NULL);

+			return 0;

+		}

+		/* So we know we're the multi-mount root */

+		me->multi = me;

+

 		age = me->age;

-		pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cur_state);

-		cache_multi_writelock(me);

 		/* It's a multi-mount; deal with it */

 		do {

 			char *path, *myoptions, *loc;