[PATCH] dm: raid1: fix waiting for io on suspend

All device-mapper targets must complete outstanding I/O before suspending.
The mirror target generates I/O in its recovery phase and fails to wait for
it.  It needs to be tracked so we can ensure that it has completed before we
suspend.

[akpm@osdl.org: cleanup]
Signed-off-by: Jonathan E Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: <dm-devel@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 21 insertions, 1 deletions

diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 659224cb7c5..48a653b3f51 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -24,6 +24,7 @@
 
 static struct workqueue_struct *_kmirrord_wq;
 static struct work_struct _kmirrord_work;
+static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
 
 static inline void wake(void)
 {
@@ -83,6 +84,7 @@ struct region_hash {
         struct list_head *buckets;
 
         spinlock_t region_lock;
+        atomic_t recovery_in_flight;
         struct semaphore recovery_count;
         struct list_head clean_regions;
         struct list_head quiesced_regions;
@@ -191,6 +193,7 @@ static int rh_init(struct region_hash *rh, struct mirror_set *ms,
 
         spin_lock_init(&rh->region_lock);
         sema_init(&rh->recovery_count, 0);
+        atomic_set(&rh->recovery_in_flight, 0);
         INIT_LIST_HEAD(&rh->clean_regions);
         INIT_LIST_HEAD(&rh->quiesced_regions);
         INIT_LIST_HEAD(&rh->recovered_regions);
@@ -382,6 +385,8 @@ static void rh_update_states(struct region_hash *rh)
                 rh->log->type->clear_region(rh->log, reg->key);
                 rh->log->type->complete_resync_work(rh->log, reg->key, 1);
                 dispatch_bios(rh->ms, &reg->delayed_bios);
+                if (atomic_dec_and_test(&rh->recovery_in_flight))
+                        wake_up_all(&_kmirrord_recovery_stopped);
                 up(&rh->recovery_count);
                 mempool_free(reg, rh->region_pool);
         }
@@ -502,11 +507,21 @@ static int __rh_recovery_prepare(struct region_hash *rh)
 
 static void rh_recovery_prepare(struct region_hash *rh)
 {
-        while (!down_trylock(&rh->recovery_count))
+        /* Extra reference to avoid race with rh_stop_recovery */
+        atomic_inc(&rh->recovery_in_flight);
+
+        while (!down_trylock(&rh->recovery_count)) {
+                atomic_inc(&rh->recovery_in_flight);
                 if (__rh_recovery_prepare(rh) <= 0) {
+                        atomic_dec(&rh->recovery_in_flight);
                         up(&rh->recovery_count);
                         break;
                 }
+        }
+
+        /* Drop the extra reference */
+        if (atomic_dec_and_test(&rh->recovery_in_flight))
+                wake_up_all(&_kmirrord_recovery_stopped);
 }
 
 /*
@@ -1177,6 +1192,11 @@ static void mirror_postsuspend(struct dm_target *ti)
         struct dirty_log *log = ms->rh.log;
 
         rh_stop_recovery(&ms->rh);
+
+        /* Wait for all I/O we generated to complete */
+        wait_event(_kmirrord_recovery_stopped,
+                   !atomic_read(&ms->rh.recovery_in_flight));
+
         if (log->type->suspend && log->type->suspend(log))
                 /* FIXME: need better error handling */
                 DMWARN("log suspend failed");