Btrfs: do not merge rbios if their fail stripe index are not identical

[uclinux-h8/linux.git] / fs / btrfs / raid56.c

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index a7f7925..7b382ee 100644 (file)
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -231,7 +231,6 @@ int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
                cur = h + i;
                INIT_LIST_HEAD(&cur->hash_list);
                spin_lock_init(&cur->lock);
-               init_waitqueue_head(&cur->wait);
        }
 
        x = cmpxchg(&info->stripe_hash_table, NULL, table);
@@ -595,14 +594,31 @@ static int rbio_can_merge(struct btrfs_raid_bio *last,
         * bio list here, anyone else that wants to
         * change this stripe needs to do their own rmw.
         */
-       if (last->operation == BTRFS_RBIO_PARITY_SCRUB ||
-           cur->operation == BTRFS_RBIO_PARITY_SCRUB)
+       if (last->operation == BTRFS_RBIO_PARITY_SCRUB)
                return 0;
 
-       if (last->operation == BTRFS_RBIO_REBUILD_MISSING ||
-           cur->operation == BTRFS_RBIO_REBUILD_MISSING)
+       if (last->operation == BTRFS_RBIO_REBUILD_MISSING)
                return 0;
 
+       if (last->operation == BTRFS_RBIO_READ_REBUILD) {
+               int fa = last->faila;
+               int fb = last->failb;
+               int cur_fa = cur->faila;
+               int cur_fb = cur->failb;
+
+               if (last->faila >= last->failb) {
+                       fa = last->failb;
+                       fb = last->faila;
+               }
+
+               if (cur->faila >= cur->failb) {
+                       cur_fa = cur->failb;
+                       cur_fb = cur->faila;
+               }
+
+               if (fa != cur_fa || fb != cur_fb)
+                       return 0;
+       }
        return 1;
 }
 
@@ -670,7 +686,6 @@ static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
        struct btrfs_raid_bio *cur;
        struct btrfs_raid_bio *pending;
        unsigned long flags;
-       DEFINE_WAIT(wait);
        struct btrfs_raid_bio *freeit = NULL;
        struct btrfs_raid_bio *cache_drop = NULL;
        int ret = 0;
@@ -816,15 +831,6 @@ static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
                        }
 
                        goto done_nolock;
-                       /*
-                        * The barrier for this waitqueue_active is not needed,
-                        * we're protected by h->lock and can't miss a wakeup.
-                        */
-               } else if (waitqueue_active(&h->wait)) {
-                       spin_unlock(&rbio->bio_list_lock);
-                       spin_unlock_irqrestore(&h->lock, flags);
-                       wake_up(&h->wait);
-                       goto done_nolock;
                }
        }
 done:
@@ -2170,11 +2176,21 @@ int raid56_parity_recover(struct btrfs_fs_info *fs_info, struct bio *bio,
        }
 
        /*
-        * reconstruct from the q stripe if they are
-        * asking for mirror 3
+        * Loop retry:
+        * for 'mirror == 2', reconstruct from all other stripes.
+        * for 'mirror_num > 2', select a stripe to fail on every retry.
         */
-       if (mirror_num == 3)
-               rbio->failb = rbio->real_stripes - 2;
+       if (mirror_num > 2) {
+               /*
+                * 'mirror == 3' is to fail the p stripe and
+                * reconstruct from the q stripe.  'mirror > 3' is to
+                * fail a data stripe and reconstruct from p+q stripe.
+                */
+               rbio->failb = rbio->real_stripes - (mirror_num - 1);
+               ASSERT(rbio->failb > 0);
+               if (rbio->failb <= rbio->faila)
+                       rbio->failb--;
+       }
 
        ret = lock_stripe_add(rbio);