1 files changed, 43 insertions, 25 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 0c1b8520ef86..785806bdb248 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -63,6 +63,7 @@ struct multipath {
         unsigned nr_priority_groups;
         struct list_head priority_groups;
         unsigned pg_init_required;      /* pg_init needs calling? */
+        unsigned pg_init_in_progress;   /* Only one pg_init allowed at once */
 
         unsigned nr_valid_paths;        /* Total number of usable paths */
         struct pgpath *current_pgpath;
@@ -72,7 +73,7 @@ struct multipath {
 
         unsigned queue_io;              /* Must we queue all I/O? */
         unsigned queue_if_no_path;      /* Queue I/O if last path fails? */
-        unsigned suspended;             /* Has dm core suspended our I/O? */
+        unsigned saved_queue_if_no_path;/* Saved state during suspension */
 
         struct work_struct process_queued_ios;
         struct bio_list queued_ios;
@@ -304,11 +305,12 @@ static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio,
                 m->queue_size--;
 
         if ((pgpath && m->queue_io) ||
-            (!pgpath && m->queue_if_no_path && !m->suspended)) {
+            (!pgpath && m->queue_if_no_path)) {
                 /* Queue for the daemon to resubmit */
                 bio_list_add(&m->queued_ios, bio);
                 m->queue_size++;
-                if (m->pg_init_required || !m->queue_io)
+                if ((m->pg_init_required && !m->pg_init_in_progress) ||
+                    !m->queue_io)
                         queue_work(kmultipathd, &m->process_queued_ios);
                 pgpath = NULL;
                 r = 0;
@@ -333,8 +335,9 @@ static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path)
 
         spin_lock_irqsave(&m->lock, flags);
 
+        m->saved_queue_if_no_path = m->queue_if_no_path;
         m->queue_if_no_path = queue_if_no_path;
-        if (!m->queue_if_no_path)
+        if (!m->queue_if_no_path && m->queue_size)
                 queue_work(kmultipathd, &m->process_queued_ios);
 
         spin_unlock_irqrestore(&m->lock, flags);
@@ -379,25 +382,31 @@ static void process_queued_ios(void *data)
 {
         struct multipath *m = (struct multipath *) data;
         struct hw_handler *hwh = &m->hw_handler;
-        struct pgpath *pgpath;
-        unsigned init_required, must_queue = 0;
+        struct pgpath *pgpath = NULL;
+        unsigned init_required = 0, must_queue = 1;
         unsigned long flags;
 
         spin_lock_irqsave(&m->lock, flags);
 
+        if (!m->queue_size)
+                goto out;
+
         if (!m->current_pgpath)
                 __choose_pgpath(m);
 
         pgpath = m->current_pgpath;
 
-        if ((pgpath && m->queue_io) ||
-            (!pgpath && m->queue_if_no_path && !m->suspended))
-                must_queue = 1;
+        if ((pgpath && !m->queue_io) ||
+            (!pgpath && !m->queue_if_no_path))
+                must_queue = 0;
 
-        init_required = m->pg_init_required;
-        if (init_required)
+        if (m->pg_init_required && !m->pg_init_in_progress) {
                 m->pg_init_required = 0;
+                m->pg_init_in_progress = 1;
+                init_required = 1;
+        }
 
+out:
         spin_unlock_irqrestore(&m->lock, flags);
 
         if (init_required)
@@ -752,6 +761,8 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
 static void multipath_dtr(struct dm_target *ti)
 {
         struct multipath *m = (struct multipath *) ti->private;
+
+        flush_workqueue(kmultipathd);
         free_multipath(m);
 }
 
@@ -765,6 +776,9 @@ static int multipath_map(struct dm_target *ti, struct bio *bio,
         struct mpath_io *mpio;
         struct multipath *m = (struct multipath *) ti->private;
 
+        if (bio_barrier(bio))
+                return -EOPNOTSUPP;
+
         mpio = mempool_alloc(m->mpio_pool, GFP_NOIO);
         dm_bio_record(&mpio->details, bio);
 
@@ -837,7 +851,7 @@ static int reinstate_path(struct pgpath *pgpath)
         pgpath->path.is_active = 1;
 
         m->current_pgpath = NULL;
-        if (!m->nr_valid_paths++)
+        if (!m->nr_valid_paths++ && m->queue_size)
                 queue_work(kmultipathd, &m->process_queued_ios);
 
         queue_work(kmultipathd, &m->trigger_event);
@@ -963,12 +977,13 @@ void dm_pg_init_complete(struct path *path, unsigned err_flags)
                 bypass_pg(m, pg, 1);
 
         spin_lock_irqsave(&m->lock, flags);
-        if (!err_flags)
-                m->queue_io = 0;
-        else {
+        if (err_flags) {
                 m->current_pgpath = NULL;
                 m->current_pg = NULL;
-        }
+        } else if (!m->pg_init_required)
+                m->queue_io = 0;
+
+        m->pg_init_in_progress = 0;
         queue_work(kmultipathd, &m->process_queued_ios);
         spin_unlock_irqrestore(&m->lock, flags);
 }
@@ -988,9 +1003,12 @@ static int do_end_io(struct multipath *m, struct bio *bio,
         if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
                 return error;
 
+        if (error == -EOPNOTSUPP)
+                return error;
+
         spin_lock(&m->lock);
         if (!m->nr_valid_paths) {
-                if (!m->queue_if_no_path || m->suspended) {
+                if (!m->queue_if_no_path) {
                         spin_unlock(&m->lock);
                         return -EIO;
                 } else {
@@ -1051,27 +1069,27 @@ static int multipath_end_io(struct dm_target *ti, struct bio *bio,
 
 /*
  * Suspend can't complete until all the I/O is processed so if
- * the last path failed we will now error any queued I/O.
+ * the last path fails we must error any remaining I/O.
+ * Note that if the freeze_bdev fails while suspending, the
+ * queue_if_no_path state is lost - userspace should reset it.
  */
 static void multipath_presuspend(struct dm_target *ti)
 {
         struct multipath *m = (struct multipath *) ti->private;
-        unsigned long flags;
 
-        spin_lock_irqsave(&m->lock, flags);
-        m->suspended = 1;
-        if (m->queue_if_no_path)
-                queue_work(kmultipathd, &m->process_queued_ios);
-        spin_unlock_irqrestore(&m->lock, flags);
+        queue_if_no_path(m, 0);
 }
 
+/*
+ * Restore the queue_if_no_path setting.
+ */
 static void multipath_resume(struct dm_target *ti)
 {
         struct multipath *m = (struct multipath *) ti->private;
         unsigned long flags;
 
         spin_lock_irqsave(&m->lock, flags);
-        m->suspended = 0;
+        m->queue_if_no_path = m->saved_queue_if_no_path;
         spin_unlock_irqrestore(&m->lock, flags);
 }