diff options
| author | Shaohua Li | 2012-07-19 08:01:31 +0200 |
|---|---|---|
| committer | NeilBrown | 2012-07-19 08:01:31 +0200 |
| commit | 7eaf7e8eb31747e4259d60288b44b194fb3d56c7 (patch) | |
| tree | bd084366fa8b61fd1eec312b54d0e861a39fba18 /drivers/md | |
| parent | raid5: lockless access raid5 overrided bi_phys_segments (diff) | |
| download | kernel-qcow2-linux-7eaf7e8eb31747e4259d60288b44b194fb3d56c7.tar.gz kernel-qcow2-linux-7eaf7e8eb31747e4259d60288b44b194fb3d56c7.tar.xz kernel-qcow2-linux-7eaf7e8eb31747e4259d60288b44b194fb3d56c7.zip | |
raid5: remove unnecessary bitmap write optimization
Neil pointed out the bitmap write optimization in handle_stripe_clean_event()
is unnecessary, because the chance one stripe gets written twice in the mean
time is rare. We can always do a bitmap_startwrite when a write request is
added to a stripe and bitmap_endwrite after write request is done. Delete the
optimization. With it, we can delete some cases of device_lock.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/raid5.c | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 6ef1eeb68f7c..9ad452c6d7e3 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2357,7 +2357,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in spin_lock_irq(&conf->device_lock); if (forwrite) { bip = &sh->dev[dd_idx].towrite; - if (*bip == NULL && sh->dev[dd_idx].written == NULL) + if (*bip == NULL) firstwrite = 1; } else bip = &sh->dev[dd_idx].toread; @@ -2458,6 +2458,7 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh, /* fail all writes first */ bi = sh->dev[i].towrite; sh->dev[i].towrite = NULL; + spin_unlock_irq(&conf->device_lock); if (bi) { s->to_write--; bitmap_end = 1; @@ -2477,6 +2478,10 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh, } bi = nextbi; } + if (bitmap_end) + bitmap_endwrite(conf->mddev->bitmap, sh->sector, + STRIPE_SECTORS, 0, 0); + bitmap_end = 0; /* and fail all 'written' */ bi = sh->dev[i].written; sh->dev[i].written = NULL; @@ -2516,7 +2521,6 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh, bi = nextbi; } } - spin_unlock_irq(&conf->device_lock); if (bitmap_end) bitmap_endwrite(conf->mddev->bitmap, sh->sector, STRIPE_SECTORS, 0, 0); @@ -2720,9 +2724,7 @@ static void handle_stripe_clean_event(struct r5conf *conf, test_bit(R5_UPTODATE, &dev->flags)) { /* We can return any write requests */ struct bio *wbi, *wbi2; - int bitmap_end = 0; pr_debug("Return write for disc %d\n", i); - spin_lock_irq(&conf->device_lock); wbi = dev->written; dev->written = NULL; while (wbi && wbi->bi_sector < @@ -2735,15 +2737,10 @@ static void handle_stripe_clean_event(struct r5conf *conf, } wbi = wbi2; } - if (dev->towrite == NULL) - bitmap_end = 1; - spin_unlock_irq(&conf->device_lock); - if (bitmap_end) - bitmap_endwrite(conf->mddev->bitmap, - sh->sector, - STRIPE_SECTORS, + bitmap_endwrite(conf->mddev->bitmap, sh->sector, + STRIPE_SECTORS, !test_bit(STRIPE_DEGRADED, &sh->state), - 0); + 0); } } |