1 files changed, 60 insertions, 27 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 017f58113c33..32389d2f18fc 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -537,7 +537,8 @@ static int read_balance(conf_t *conf, r10bio_t *r10_bio)
         current_distance = abs(r10_bio->devs[slot].addr -
                                conf->mirrors[disk].head_position);
 
-        /* Find the disk whose head is closest */
+        /* Find the disk whose head is closest,
+         * or - for far > 1 - find the closest to partition beginning */
 
         for (nslot = slot; nslot < conf->copies; nslot++) {
                 int ndisk = r10_bio->devs[nslot].devnum;
@@ -557,8 +558,13 @@ static int read_balance(conf_t *conf, r10bio_t *r10_bio)
                         slot = nslot;
                         break;
                 }
-                new_distance = abs(r10_bio->devs[nslot].addr -
-                                   conf->mirrors[ndisk].head_position);
+
+                /* for far > 1 always use the lowest address */
+                if (conf->far_copies > 1)
+                        new_distance = r10_bio->devs[nslot].addr;
+                else
+                        new_distance = abs(r10_bio->devs[nslot].addr -
+                                           conf->mirrors[ndisk].head_position);
                 if (new_distance < current_distance) {
                         current_distance = new_distance;
                         disk = ndisk;
@@ -629,7 +635,36 @@ static int raid10_congested(void *data, int bits)
         return ret;
 }
 
-
+static int flush_pending_writes(conf_t *conf)
+{
+        /* Any writes that have been queued but are awaiting
+         * bitmap updates get flushed here.
+         * We return 1 if any requests were actually submitted.
+         */
+        int rv = 0;
+
+        spin_lock_irq(&conf->device_lock);
+
+        if (conf->pending_bio_list.head) {
+                struct bio *bio;
+                bio = bio_list_get(&conf->pending_bio_list);
+                blk_remove_plug(conf->mddev->queue);
+                spin_unlock_irq(&conf->device_lock);
+                /* flush any pending bitmap writes to disk
+                 * before proceeding w/ I/O */
+                bitmap_unplug(conf->mddev->bitmap);
+
+                while (bio) { /* submit pending writes */
+                        struct bio *next = bio->bi_next;
+                        bio->bi_next = NULL;
+                        generic_make_request(bio);
+                        bio = next;
+                }
+                rv = 1;
+        } else
+                spin_unlock_irq(&conf->device_lock);
+        return rv;
+}
 /* Barriers....
  * Sometimes we need to suspend IO while we do something else,
  * either some resync/recovery, or reconfigure the array.
@@ -712,15 +747,23 @@ static void freeze_array(conf_t *conf)
         /* stop syncio and normal IO and wait for everything to
          * go quiet.
          * We increment barrier and nr_waiting, and then
-         * wait until barrier+nr_pending match nr_queued+2
+         * wait until nr_pending match nr_queued+1
+         * This is called in the context of one normal IO request
+         * that has failed. Thus any sync request that might be pending
+         * will be blocked by nr_pending, and we need to wait for
+         * pending IO requests to complete or be queued for re-try.
+         * Thus the number queued (nr_queued) plus this request (1)
+         * must match the number of pending IOs (nr_pending) before
+         * we continue.
          */
         spin_lock_irq(&conf->resync_lock);
         conf->barrier++;
         conf->nr_waiting++;
         wait_event_lock_irq(conf->wait_barrier,
-                            conf->barrier+conf->nr_pending == conf->nr_queued+2,
+                            conf->nr_pending == conf->nr_queued+1,
                             conf->resync_lock,
-                            raid10_unplug(conf->mddev->queue));
+                            ({ flush_pending_writes(conf);
+                               raid10_unplug(conf->mddev->queue); }));
         spin_unlock_irq(&conf->resync_lock);
 }
 
@@ -892,6 +935,9 @@ static int make_request(struct request_queue *q, struct bio * bio)
         blk_plug_device(mddev->queue);
         spin_unlock_irqrestore(&conf->device_lock, flags);
 
+        /* In case raid10d snuck in to freeze_array */
+        wake_up(&conf->wait_barrier);
+
         if (do_sync)
                 md_wakeup_thread(mddev->thread);
 
@@ -1464,28 +1510,14 @@ static void raid10d(mddev_t *mddev)
 
         for (;;) {
                 char b[BDEVNAME_SIZE];
-                spin_lock_irqsave(&conf->device_lock, flags);
 
-                if (conf->pending_bio_list.head) {
-                        bio = bio_list_get(&conf->pending_bio_list);
-                        blk_remove_plug(mddev->queue);
-                        spin_unlock_irqrestore(&conf->device_lock, flags);
-                        /* flush any pending bitmap writes to disk before proceeding w/ I/O */
-                        bitmap_unplug(mddev->bitmap);
-
-                        while (bio) { /* submit pending writes */
-                                struct bio *next = bio->bi_next;
-                                bio->bi_next = NULL;
-                                generic_make_request(bio);
-                                bio = next;
-                        }
-                        unplug = 1;
-
-                        continue;
-                }
+                unplug += flush_pending_writes(conf);
 
-                if (list_empty(head))
+                spin_lock_irqsave(&conf->device_lock, flags);
+                if (list_empty(head)) {
+                        spin_unlock_irqrestore(&conf->device_lock, flags);
                         break;
+                }
                 r10_bio = list_entry(head->prev, r10bio_t, retry_list);
                 list_del(head->prev);
                 conf->nr_queued--;
@@ -1548,7 +1580,6 @@ static void raid10d(mddev_t *mddev)
                         }
                 }
         }
-        spin_unlock_irqrestore(&conf->device_lock, flags);
         if (unplug)
                 unplug_slaves(mddev);
 }
@@ -1787,6 +1818,8 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
                                 if (j == conf->copies) {
                                         /* Cannot recover, so abort the recovery */
                                         put_buf(r10_bio);
+                                        if (rb2)
+                                                atomic_dec(&rb2->remaining);
                                         r10_bio = rb2;
                                         if (!test_and_set_bit(MD_RECOVERY_ERR, &mddev->recovery))
                                                 printk(KERN_INFO "raid10: %s: insufficient working devices for recovery.\n",