dm snapshot: avoid allocating exceptions in merge

[safe/jmp/linux-2.6] / drivers / md / dm-mpath.c

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 32d0b87..e81345a 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -93,6 +93,10 @@ struct multipath {
         * can resubmit bios on error.
         */
        mempool_t *mpio_pool;
+
+       struct mutex work_mutex;
+
+       unsigned suspended;     /* Don't create new I/O internally when set. */
 };
 
 /*
@@ -198,6 +202,7 @@ static struct multipath *alloc_multipath(struct dm_target *ti)
                m->queue_io = 1;
                INIT_WORK(&m->process_queued_ios, process_queued_ios);
                INIT_WORK(&m->trigger_event, trigger_event);
+               mutex_init(&m->work_mutex);
                m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
                if (!m->mpio_pool) {
                        kfree(m);
@@ -885,13 +890,18 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
        return r;
 }
 
-static void multipath_dtr(struct dm_target *ti)
+static void flush_multipath_work(void)
 {
-       struct multipath *m = (struct multipath *) ti->private;
-
        flush_workqueue(kmpath_handlerd);
        flush_workqueue(kmultipathd);
        flush_scheduled_work();
+}
+
+static void multipath_dtr(struct dm_target *ti)
+{
+       struct multipath *m = ti->private;
+
+       flush_multipath_work();
        free_multipath(m);
 }
 
@@ -1116,8 +1126,9 @@ static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath)
        return limit_reached;
 }
 
-static void pg_init_done(struct dm_path *path, int errors)
+static void pg_init_done(void *data, int errors)
 {
+       struct dm_path *path = data;
        struct pgpath *pgpath = path_to_pgpath(path);
        struct priority_group *pg = pgpath->pg;
        struct multipath *m = pg->m;
@@ -1183,12 +1194,11 @@ static void pg_init_done(struct dm_path *path, int errors)
 
 static void activate_path(struct work_struct *work)
 {
-       int ret;
        struct pgpath *pgpath =
                container_of(work, struct pgpath, activate_path);
 
-       ret = scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev));
-       pg_init_done(&pgpath->path, ret);
+       scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev),
+                               pg_init_done, &pgpath->path);
 }
 
 /*
@@ -1261,6 +1271,16 @@ static void multipath_presuspend(struct dm_target *ti)
        queue_if_no_path(m, 0, 1);
 }
 
+static void multipath_postsuspend(struct dm_target *ti)
+{
+       struct multipath *m = ti->private;
+
+       mutex_lock(&m->work_mutex);
+       m->suspended = 1;
+       flush_multipath_work();
+       mutex_unlock(&m->work_mutex);
+}
+
 /*
  * Restore the queue_if_no_path setting.
  */
@@ -1269,6 +1289,10 @@ static void multipath_resume(struct dm_target *ti)
        struct multipath *m = (struct multipath *) ti->private;
        unsigned long flags;
 
+       mutex_lock(&m->work_mutex);
+       m->suspended = 0;
+       mutex_unlock(&m->work_mutex);
+
        spin_lock_irqsave(&m->lock, flags);
        m->queue_if_no_path = m->saved_queue_if_no_path;
        spin_unlock_irqrestore(&m->lock, flags);
@@ -1397,51 +1421,71 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
 
 static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
 {
-       int r;
+       int r = -EINVAL;
        struct dm_dev *dev;
        struct multipath *m = (struct multipath *) ti->private;
        action_fn action;
 
+       mutex_lock(&m->work_mutex);
+
+       if (m->suspended) {
+               r = -EBUSY;
+               goto out;
+       }
+
+       if (dm_suspended(ti)) {
+               r = -EBUSY;
+               goto out;
+       }
+
        if (argc == 1) {
-               if (!strnicmp(argv[0], MESG_STR("queue_if_no_path")))
-                       return queue_if_no_path(m, 1, 0);
-               else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path")))
-                       return queue_if_no_path(m, 0, 0);
+               if (!strnicmp(argv[0], MESG_STR("queue_if_no_path"))) {
+                       r = queue_if_no_path(m, 1, 0);
+                       goto out;
+               } else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path"))) {
+                       r = queue_if_no_path(m, 0, 0);
+                       goto out;
+               }
        }
 
-       if (argc != 2)
-               goto error;
+       if (argc != 2) {
+               DMWARN("Unrecognised multipath message received.");
+               goto out;
+       }
 
-       if (!strnicmp(argv[0], MESG_STR("disable_group")))
-               return bypass_pg_num(m, argv[1], 1);
-       else if (!strnicmp(argv[0], MESG_STR("enable_group")))
-               return bypass_pg_num(m, argv[1], 0);
-       else if (!strnicmp(argv[0], MESG_STR("switch_group")))
-               return switch_pg_num(m, argv[1]);
-       else if (!strnicmp(argv[0], MESG_STR("reinstate_path")))
+       if (!strnicmp(argv[0], MESG_STR("disable_group"))) {
+               r = bypass_pg_num(m, argv[1], 1);
+               goto out;
+       } else if (!strnicmp(argv[0], MESG_STR("enable_group"))) {
+               r = bypass_pg_num(m, argv[1], 0);
+               goto out;
+       } else if (!strnicmp(argv[0], MESG_STR("switch_group"))) {
+               r = switch_pg_num(m, argv[1]);
+               goto out;
+       } else if (!strnicmp(argv[0], MESG_STR("reinstate_path")))
                action = reinstate_path;
        else if (!strnicmp(argv[0], MESG_STR("fail_path")))
                action = fail_path;
-       else
-               goto error;
+       else {
+               DMWARN("Unrecognised multipath message received.");
+               goto out;
+       }
 
        r = dm_get_device(ti, argv[1], ti->begin, ti->len,
                          dm_table_get_mode(ti->table), &dev);
        if (r) {
                DMWARN("message: error getting device %s",
                       argv[1]);
-               return -EINVAL;
+               goto out;
        }
 
        r = action_dev(m, dev, action);
 
        dm_put_device(ti, dev);
 
+out:
+       mutex_unlock(&m->work_mutex);
        return r;
-
-error:
-       DMWARN("Unrecognised multipath message received.");
-       return -EINVAL;
 }
 
 static int multipath_ioctl(struct dm_target *ti, unsigned int cmd,
@@ -1567,13 +1611,14 @@ out:
  *---------------------------------------------------------------*/
 static struct target_type multipath_target = {
        .name = "multipath",
-       .version = {1, 1, 0},
+       .version = {1, 1, 1},
        .module = THIS_MODULE,
        .ctr = multipath_ctr,
        .dtr = multipath_dtr,
        .map_rq = multipath_map,
        .rq_end_io = multipath_end_io,
        .presuspend = multipath_presuspend,
+       .postsuspend = multipath_postsuspend,
        .resume = multipath_resume,
        .status = multipath_status,
        .message = multipath_message,