RAID5: batch adjacent full stripe write

[deliverable/linux.git] / drivers / md / dm.c

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 73f28802dc7abc3cb46dc38c8ef6fb5bb521e66b..8001fe9e3434734ad92c8109ef8fa860906238ce 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -433,7 +433,6 @@ static int dm_blk_open(struct block_device *bdev, fmode_t mode)
 
        dm_get(md);
        atomic_inc(&md->open_count);
-
 out:
        spin_unlock(&_minor_lock);
 
@@ -442,16 +441,20 @@ out:
 
 static void dm_blk_close(struct gendisk *disk, fmode_t mode)
 {
-       struct mapped_device *md = disk->private_data;
+       struct mapped_device *md;
 
        spin_lock(&_minor_lock);
 
+       md = disk->private_data;
+       if (WARN_ON(!md))
+               goto out;
+
        if (atomic_dec_and_test(&md->open_count) &&
            (test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
                queue_work(deferred_remove_workqueue, &deferred_remove_work);
 
        dm_put(md);
-
+out:
        spin_unlock(&_minor_lock);
 }
 
@@ -2241,7 +2244,6 @@ static void free_dev(struct mapped_device *md)
        int minor = MINOR(disk_devt(md->disk));
 
        unlock_fs(md);
-       bdput(md->bdev);
        destroy_workqueue(md->wq);
 
        if (md->kworker_task)
@@ -2252,19 +2254,22 @@ static void free_dev(struct mapped_device *md)
                mempool_destroy(md->rq_pool);
        if (md->bs)
                bioset_free(md->bs);
-       blk_integrity_unregister(md->disk);
-       del_gendisk(md->disk);
+
        cleanup_srcu_struct(&md->io_barrier);
        free_table_devices(&md->table_devices);
-       free_minor(minor);
+       dm_stats_cleanup(&md->stats);
 
        spin_lock(&_minor_lock);
        md->disk->private_data = NULL;
        spin_unlock(&_minor_lock);
-
+       if (blk_get_integrity(md->disk))
+               blk_integrity_unregister(md->disk);
+       del_gendisk(md->disk);
        put_disk(md->disk);
        blk_cleanup_queue(md->queue);
-       dm_stats_cleanup(&md->stats);
+       bdput(md->bdev);
+       free_minor(minor);
+
        module_put(THIS_MODULE);
        kfree(md);
 }
@@ -2616,6 +2621,19 @@ void dm_get(struct mapped_device *md)
        BUG_ON(test_bit(DMF_FREEING, &md->flags));
 }
 
+int dm_hold(struct mapped_device *md)
+{
+       spin_lock(&_minor_lock);
+       if (test_bit(DMF_FREEING, &md->flags)) {
+               spin_unlock(&_minor_lock);
+               return -EBUSY;
+       }
+       dm_get(md);
+       spin_unlock(&_minor_lock);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(dm_hold);
+
 const char *dm_device_name(struct mapped_device *md)
 {
        return md->name;
@@ -2629,8 +2647,9 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
 
        might_sleep();
 
-       spin_lock(&_minor_lock);
        map = dm_get_live_table(md, &srcu_idx);
+
+       spin_lock(&_minor_lock);
        idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
        set_bit(DMF_FREEING, &md->flags);
        spin_unlock(&_minor_lock);
@@ -2638,10 +2657,16 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
        if (dm_request_based(md))
                flush_kthread_worker(&md->kworker);
 
+       /*
+        * Take suspend_lock so that presuspend and postsuspend methods
+        * do not race with internal suspend.
+        */
+       mutex_lock(&md->suspend_lock);
        if (!dm_suspended_md(md)) {
                dm_table_presuspend_targets(map);
                dm_table_postsuspend_targets(map);
        }
+       mutex_unlock(&md->suspend_lock);
 
        /* dm_put_live_table must be before msleep, otherwise deadlock is possible */
        dm_put_live_table(md, srcu_idx);
@@ -3115,6 +3140,7 @@ void dm_internal_suspend_fast(struct mapped_device *md)
        flush_workqueue(md->wq);
        dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
 }
+EXPORT_SYMBOL_GPL(dm_internal_suspend_fast);
 
 void dm_internal_resume_fast(struct mapped_device *md)
 {
@@ -3126,6 +3152,7 @@ void dm_internal_resume_fast(struct mapped_device *md)
 done:
        mutex_unlock(&md->suspend_lock);
 }
+EXPORT_SYMBOL_GPL(dm_internal_resume_fast);
 
 /*-----------------------------------------------------------------
  * Event notification.