Merge branch 'for-upstream-master' of git://github.com/agraf/linux-2.6

[cascardo/linux.git] / drivers / md / dm-mpath.c

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index c351607..638dae0 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -18,6 +18,7 @@
 #include <linux/slab.h>
 #include <linux/time.h>
 #include <linux/workqueue.h>
+#include <linux/delay.h>
 #include <scsi/scsi_dh.h>
 #include <linux/atomic.h>
 
@@ -329,14 +330,18 @@ static void __choose_pgpath(struct multipath *m, size_t nr_bytes)
        /*
         * Loop through priority groups until we find a valid path.
         * First time we skip PGs marked 'bypassed'.
-        * Second time we only try the ones we skipped.
+        * Second time we only try the ones we skipped, but set
+        * pg_init_delay_retry so we do not hammer controllers.
         */
        do {
                list_for_each_entry(pg, &m->priority_groups, list) {
                        if (pg->bypassed == bypassed)
                                continue;
-                       if (!__choose_path_in_pg(m, pg, nr_bytes))
+                       if (!__choose_path_in_pg(m, pg, nr_bytes)) {
+                               if (!bypassed)
+                                       m->pg_init_delay_retry = 1;
                                return;
+                       }
                }
        } while (bypassed--);
 
@@ -482,9 +487,6 @@ static void process_queued_ios(struct work_struct *work)
 
        spin_lock_irqsave(&m->lock, flags);
 
-       if (!m->queue_size)
-               goto out;
-
        if (!m->current_pgpath)
                __choose_pgpath(m, 0);
 
@@ -497,7 +499,6 @@ static void process_queued_ios(struct work_struct *work)
        if (m->pg_init_required && !m->pg_init_in_progress && pgpath)
                __pg_init_all_paths(m);
 
-out:
        spin_unlock_irqrestore(&m->lock, flags);
        if (!must_queue)
                dispatch_queued_ios(m);
@@ -1518,11 +1519,16 @@ out:
 static int multipath_ioctl(struct dm_target *ti, unsigned int cmd,
                           unsigned long arg)
 {
-       struct multipath *m = (struct multipath *) ti->private;
-       struct block_device *bdev = NULL;
-       fmode_t mode = 0;
+       struct multipath *m = ti->private;
+       struct block_device *bdev;
+       fmode_t mode;
        unsigned long flags;
-       int r = 0;
+       int r;
+
+again:
+       bdev = NULL;
+       mode = 0;
+       r = 0;
 
        spin_lock_irqsave(&m->lock, flags);
 
@@ -1547,6 +1553,12 @@ static int multipath_ioctl(struct dm_target *ti, unsigned int cmd,
        if (!r && ti->len != i_size_read(bdev->bd_inode) >> SECTOR_SHIFT)
                r = scsi_verify_blk_ioctl(NULL, cmd);
 
+       if (r == -EAGAIN && !fatal_signal_pending(current)) {
+               queue_work(kmultipathd, &m->process_queued_ios);
+               msleep(10);
+               goto again;
+       }
+
        return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 }
 
@@ -1644,7 +1656,7 @@ out:
  *---------------------------------------------------------------*/
 static struct target_type multipath_target = {
        .name = "multipath",
-       .version = {1, 3, 0},
+       .version = {1, 4, 0},
        .module = THIS_MODULE,
        .ctr = multipath_ctr,
        .dtr = multipath_dtr,