From b5e98d65d34a1c11a2135ea8a9b2619dbc7216c8 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 2 Jan 2007 13:52:31 -0700 Subject: [PATCH] md: handle_stripe5 - add request/completion logic for async read ops When a read bio is attached to the stripe and the corresponding block is marked R5_UPTODATE, then a read (biofill) operation is scheduled to copy the data from the stripe cache to the bio buffer. handle_stripe flags the blocks to be operated on with the R5_Wantfill flag. If new read requests arrive while raid5_run_ops is running they will not be handled until handle_stripe is scheduled to run again. Changelog: * cleanup to_read and to_fill accounting * do not fail reads that have reached the cache Signed-off-by: Dan Williams Acked-By: NeilBrown --- drivers/md/raid5.c | 53 ++++++++++++++++++-------------------- include/linux/raid/raid5.h | 2 +- 2 files changed, 26 insertions(+), 29 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 810cf831edda..a33dac7c2e2f 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2049,9 +2049,12 @@ handle_requests_to_failed_array(raid5_conf_t *conf, struct stripe_head *sh, bi = bi2; } - /* fail any reads if this device is non-operational */ - if (!test_bit(R5_Insync, &sh->dev[i].flags) || - test_bit(R5_ReadError, &sh->dev[i].flags)) { + /* fail any reads if this device is non-operational and + * the data has not reached the cache yet. + */ + if (!test_bit(R5_Wantfill, &sh->dev[i].flags) && + (!test_bit(R5_Insync, &sh->dev[i].flags) || + test_bit(R5_ReadError, &sh->dev[i].flags))) { bi = sh->dev[i].toread; sh->dev[i].toread = NULL; if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) @@ -2740,37 +2743,27 @@ static void handle_stripe5(struct stripe_head *sh) struct r5dev *dev = &sh->dev[i]; clear_bit(R5_Insync, &dev->flags); - pr_debug("check %d: state 0x%lx read %p write %p written %p\n", - i, dev->flags, dev->toread, dev->towrite, dev->written); - /* maybe we can reply to a read */ - if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) { - struct bio *rbi, *rbi2; - pr_debug("Return read for disc %d\n", i); - spin_lock_irq(&conf->device_lock); - rbi = dev->toread; - dev->toread = NULL; - if (test_and_clear_bit(R5_Overlap, &dev->flags)) - wake_up(&conf->wait_for_overlap); - spin_unlock_irq(&conf->device_lock); - while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) { - copy_data(0, rbi, dev->page, dev->sector); - rbi2 = r5_next_bio(rbi, dev->sector); - spin_lock_irq(&conf->device_lock); - if (--rbi->bi_phys_segments == 0) { - rbi->bi_next = return_bi; - return_bi = rbi; - } - spin_unlock_irq(&conf->device_lock); - rbi = rbi2; - } - } + pr_debug("check %d: state 0x%lx toread %p read %p write %p " + "written %p\n", i, dev->flags, dev->toread, dev->read, + dev->towrite, dev->written); + + /* maybe we can request a biofill operation + * + * new wantfill requests are only permitted while + * STRIPE_OP_BIOFILL is clear + */ + if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread && + !test_bit(STRIPE_OP_BIOFILL, &sh->ops.pending)) + set_bit(R5_Wantfill, &dev->flags); /* now count some things */ if (test_bit(R5_LOCKED, &dev->flags)) s.locked++; if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++; if (test_bit(R5_Wantcompute, &dev->flags)) s.compute++; - if (dev->toread) + if (test_bit(R5_Wantfill, &dev->flags)) + s.to_fill++; + else if (dev->toread) s.to_read++; if (dev->towrite) { s.to_write++; @@ -2793,6 +2786,10 @@ static void handle_stripe5(struct stripe_head *sh) set_bit(R5_Insync, &dev->flags); } rcu_read_unlock(); + + if (s.to_fill && !test_and_set_bit(STRIPE_OP_BIOFILL, &sh->ops.pending)) + sh->ops.count++; + pr_debug("locked=%d uptodate=%d to_read=%d" " to_write=%d failed=%d failed_num=%d\n", s.locked, s.uptodate, s.to_read, s.to_write, diff --git a/include/linux/raid/raid5.h b/include/linux/raid/raid5.h index 2293015de1d5..93678f57ccbe 100644 --- a/include/linux/raid/raid5.h +++ b/include/linux/raid/raid5.h @@ -200,7 +200,7 @@ struct stripe_head { struct stripe_head_state { int syncing, expanding, expanded; int locked, uptodate, to_read, to_write, failed, written; - int compute, req_compute, non_overwrite; + int to_fill, compute, req_compute, non_overwrite; int failed_num; }; -- 2.20.1