raid5: track overwrite disk count

Track overwrite disk count, so we can know if a stripe is a full stripe write.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 49b0f23..e801c66 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -553,6 +553,7 @@ retry:
        }
        if (read_seqcount_retry(&conf->gen_lock, seq))
                goto retry;
+       sh->overwrite_disks = 0;
        insert_hash(conf, sh);
        sh->cpu = smp_processor_id();
        set_bit(STRIPE_BATCH_READY, &sh->state);
@@ -710,6 +711,12 @@ get_active_stripe(struct r5conf *conf, sector_t sector,
        return sh;
 }
 
+static bool is_full_stripe_write(struct stripe_head *sh)
+{
+       BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
+       return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
+}
+
 /* Determine if 'data_offset' or 'new_data_offset' should be used
  * in this stripe_head.
  */
@@ -1413,6 +1420,7 @@ ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
                        spin_lock_irq(&sh->stripe_lock);
                        chosen = dev->towrite;
                        dev->towrite = NULL;
+                       sh->overwrite_disks = 0;
                        BUG_ON(dev->written);
                        wbi = dev->written = chosen;
                        spin_unlock_irq(&sh->stripe_lock);
@@ -2700,7 +2708,8 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
                                sector = bio_end_sector(bi);
                }
                if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
-                       set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
+                       if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
+                               sh->overwrite_disks++;
        }
 
        pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
@@ -2772,6 +2781,7 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
                /* fail all writes first */
                bi = sh->dev[i].towrite;
                sh->dev[i].towrite = NULL;
+               sh->overwrite_disks = 0;
                spin_unlock_irq(&sh->stripe_lock);
                if (bi)
                        bitmap_end = 1;
@@ -4630,12 +4640,14 @@ static void make_discard_request(struct mddev *mddev, struct bio *bi)
                }
                set_bit(STRIPE_DISCARD, &sh->state);
                finish_wait(&conf->wait_for_overlap, &w);
+               sh->overwrite_disks = 0;
                for (d = 0; d < conf->raid_disks; d++) {
                        if (d == sh->pd_idx || d == sh->qd_idx)
                                continue;
                        sh->dev[d].towrite = bi;
                        set_bit(R5_OVERWRITE, &sh->dev[d].flags);
                        raid5_inc_bi_active_stripes(bi);
+                       sh->overwrite_disks++;
                }
                spin_unlock_irq(&sh->stripe_lock);
                if (conf->mddev->bitmap) {

diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 37644e3..4cc1a48 100644 (file)
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -210,6 +210,10 @@ struct stripe_head {
        atomic_t                count;        /* nr of active thread/requests */
        int                     bm_seq; /* sequence number for bitmap flushes */
        int                     disks;          /* disks in stripe */
+       int                     overwrite_disks; /* total overwrite disks in stripe,
+                                                 * this is only checked when stripe
+                                                 * has STRIPE_BATCH_READY
+                                                 */
        enum check_states       check_state;
        enum reconstruct_states reconstruct_state;
        spinlock_t              stripe_lock;