X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fmd%2Fmultipath.c;h=63f81fd3d25a801d24d4ba016242ed1d2a711379;hb=6a77f38946aaee1cd85eeec6cf4229b204c15071;hp=9d79b2abac1d92b4f4df01ee6a9229a349a24f6d;hpb=87fc8d1bb10cd459024a742c6a10961fefcef18f;p=linux-2.6.git

diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 9d79b2aba..63f81fd3d 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -36,8 +36,6 @@
 
 
 static mdk_personality_t multipath_personality;
-static spinlock_t retry_list_lock = SPIN_LOCK_UNLOCKED;
-struct multipath_bh *multipath_retry_list = NULL, **multipath_retry_tail;
 
 
 static void *mp_pool_alloc(int gfp_flags, void *data)
@@ -63,16 +61,16 @@ static int multipath_map (multipath_conf_t *conf)
 	 * now we use the first available disk.
 	 */
 
-	spin_lock_irq(&conf->device_lock);
+	rcu_read_lock();
 	for (i = 0; i < disks; i++) {
 		mdk_rdev_t *rdev = conf->multipaths[i].rdev;
 		if (rdev && rdev->in_sync) {
 			atomic_inc(&rdev->nr_pending);
-			spin_unlock_irq(&conf->device_lock);
+			rcu_read_unlock();
 			return i;
 		}
 	}
-	spin_unlock_irq(&conf->device_lock);
+	rcu_read_unlock();
 
 	printk(KERN_ERR "multipath_map(): no more operational IO paths?\n");
 	return (-1);
@@ -82,14 +80,11 @@ static void multipath_reschedule_retry (struct multipath_bh *mp_bh)
 {
 	unsigned long flags;
 	mddev_t *mddev = mp_bh->mddev;
+	multipath_conf_t *conf = mddev_to_conf(mddev);
 
-	spin_lock_irqsave(&retry_list_lock, flags);
-	if (multipath_retry_list == NULL)
-		multipath_retry_tail = &multipath_retry_list;
-	*multipath_retry_tail = mp_bh;
-	multipath_retry_tail = &mp_bh->next_mp;
-	mp_bh->next_mp = NULL;
-	spin_unlock_irqrestore(&retry_list_lock, flags);
+	spin_lock_irqsave(&conf->device_lock, flags);
+	list_add(&mp_bh->retry_list, &conf->retry_list);
+	spin_unlock_irqrestore(&conf->device_lock, flags);
 	md_wakeup_thread(mddev->thread);
 }
 
@@ -140,26 +135,26 @@ static void unplug_slaves(mddev_t *mddev)
 {
 	multipath_conf_t *conf = mddev_to_conf(mddev);
 	int i;
-	unsigned long flags;
 
-	spin_lock_irqsave(&conf->device_lock, flags);
+	rcu_read_lock();
 	for (i=0; i<mddev->raid_disks; i++) {
 		mdk_rdev_t *rdev = conf->multipaths[i].rdev;
-		if (rdev && !rdev->faulty) {
+		if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) {
 			request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
 
 			atomic_inc(&rdev->nr_pending);
-			spin_unlock_irqrestore(&conf->device_lock, flags);
+			rcu_read_unlock();
 
 			if (r_queue->unplug_fn)
 				r_queue->unplug_fn(r_queue);
 
-			spin_lock_irqsave(&conf->device_lock, flags);
-			atomic_dec(&rdev->nr_pending);
+			rdev_dec_pending(rdev, mddev);
+			rcu_read_lock();
 		}
 	}
-	spin_unlock_irqrestore(&conf->device_lock, flags);
+	rcu_read_unlock();
 }
+
 static void multipath_unplug(request_queue_t *q)
 {
 	unplug_slaves(q->queuedata);
@@ -195,6 +190,7 @@ static int multipath_make_request (request_queue_t *q, struct bio * bio)
 	multipath = conf->multipaths + mp_bh->path;
 
 	mp_bh->bio = *bio;
+	mp_bh->bio.bi_sector += multipath->rdev->data_offset;
 	mp_bh->bio.bi_bdev = multipath->rdev->bdev;
 	mp_bh->bio.bi_rw |= (1 << BIO_RW_FAILFAST);
 	mp_bh->bio.bi_end_io = multipath_end_request;
@@ -224,22 +220,26 @@ static int multipath_issue_flush(request_queue_t *q, struct gendisk *disk,
 	multipath_conf_t *conf = mddev_to_conf(mddev);
 	int i, ret = 0;
 
-	for (i=0; i<mddev->raid_disks; i++) {
+	rcu_read_lock();
+	for (i=0; i<mddev->raid_disks && ret == 0; i++) {
 		mdk_rdev_t *rdev = conf->multipaths[i].rdev;
 		if (rdev && !rdev->faulty) {
 			struct block_device *bdev = rdev->bdev;
 			request_queue_t *r_queue = bdev_get_queue(bdev);
 
-			if (!r_queue->issue_flush_fn) {
+			if (!r_queue->issue_flush_fn)
 				ret = -EOPNOTSUPP;
-				break;
+			else {
+				atomic_inc(&rdev->nr_pending);
+				rcu_read_unlock();
+				ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
+							      error_sector);
+				rdev_dec_pending(rdev, mddev);
+				rcu_read_lock();
 			}
-
-			ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
-			if (ret)
-				break;
 		}
 	}
+	rcu_read_unlock();
 	return ret;
 }
 
@@ -310,10 +310,9 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 	struct multipath_info *p;
 
 	print_multipath_conf(conf);
-	spin_lock_irq(&conf->device_lock);
+
 	for (path=0; path<mddev->raid_disks; path++) 
 		if ((p=conf->multipaths+path)->rdev == NULL) {
-			p->rdev = rdev;
 			blk_queue_stack_limits(mddev->queue,
 					       rdev->bdev->bd_disk->queue);
 
@@ -330,9 +329,9 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 			conf->working_disks++;
 			rdev->raid_disk = path;
 			rdev->in_sync = 1;
+			p->rdev = rdev;
 			found = 1;
 		}
-	spin_unlock_irq(&conf->device_lock);
 
 	print_multipath_conf(conf);
 	return found;
@@ -341,26 +340,29 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 static int multipath_remove_disk(mddev_t *mddev, int number)
 {
 	multipath_conf_t *conf = mddev->private;
-	int err = 1;
+	int err = 0;
+	mdk_rdev_t *rdev;
 	struct multipath_info *p = conf->multipaths + number;
 
 	print_multipath_conf(conf);
-	spin_lock_irq(&conf->device_lock);
 
-	if (p->rdev) {
-		if (p->rdev->in_sync ||
-		    atomic_read(&p->rdev->nr_pending)) {
+	rdev = p->rdev;
+	if (rdev) {
+		if (rdev->in_sync ||
+		    atomic_read(&rdev->nr_pending)) {
 			printk(KERN_ERR "hot-remove-disk, slot %d is identified"				" but is still operational!\n", number);
 			err = -EBUSY;
 			goto abort;
 		}
 		p->rdev = NULL;
-		err = 0;
+		synchronize_kernel();
+		if (atomic_read(&rdev->nr_pending)) {
+			/* lost the race, try later */
+			err = -EBUSY;
+			p->rdev = rdev;
+		}
 	}
-	if (err)
-		MD_BUG();
 abort:
-	spin_unlock_irq(&conf->device_lock);
 
 	print_multipath_conf(conf);
 	return err;
@@ -382,18 +384,18 @@ static void multipathd (mddev_t *mddev)
 	struct bio *bio;
 	unsigned long flags;
 	multipath_conf_t *conf = mddev_to_conf(mddev);
+	struct list_head *head = &conf->retry_list;
 
 	md_check_recovery(mddev);
 	for (;;) {
 		char b[BDEVNAME_SIZE];
-		spin_lock_irqsave(&retry_list_lock, flags);
-		mp_bh = multipath_retry_list;
-		if (!mp_bh)
+		spin_lock_irqsave(&conf->device_lock, flags);
+		if (list_empty(head))
 			break;
-		multipath_retry_list = mp_bh->next_mp;
-		spin_unlock_irqrestore(&retry_list_lock, flags);
+		mp_bh = list_entry(head->prev, struct multipath_bh, retry_list);
+		list_del(head->prev);
+		spin_unlock_irqrestore(&conf->device_lock, flags);
 
-		mddev = mp_bh->mddev;
 		bio = &mp_bh->bio;
 		bio->bi_sector = mp_bh->master_bio->bi_sector;
 		
@@ -409,6 +411,7 @@ static void multipathd (mddev_t *mddev)
 				bdevname(bio->bi_bdev,b),
 				(unsigned long long)bio->bi_sector);
 			*bio = *(mp_bh->master_bio);
+			bio->bi_sector += conf->multipaths[mp_bh->path].rdev->data_offset;
 			bio->bi_bdev = conf->multipaths[mp_bh->path].rdev->bdev;
 			bio->bi_rw |= (1 << BIO_RW_FAILFAST);
 			bio->bi_end_io = multipath_end_request;
@@ -416,7 +419,7 @@ static void multipathd (mddev_t *mddev)
 			generic_make_request(bio);
 		}
 	}
-	spin_unlock_irqrestore(&retry_list_lock, flags);
+	spin_unlock_irqrestore(&conf->device_lock, flags);
 }
 
 static int multipath_run (mddev_t *mddev)
@@ -488,7 +491,8 @@ static int multipath_run (mddev_t *mddev)
 	conf->raid_disks = mddev->raid_disks;
 	mddev->sb_dirty = 1;
 	conf->mddev = mddev;
-	conf->device_lock = SPIN_LOCK_UNLOCKED;
+	spin_lock_init(&conf->device_lock);
+	INIT_LIST_HEAD(&conf->retry_list);
 
 	if (!conf->working_disks) {
 		printk(KERN_ERR "multipath: no operational IO paths for %s\n",
@@ -543,6 +547,7 @@ static int multipath_stop (mddev_t *mddev)
 
 	md_unregister_thread(mddev->thread);
 	mddev->thread = NULL;
+	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
 	mempool_destroy(conf->pool);
 	kfree(conf->multipaths);
 	kfree(conf);