From: NeilBrown Date: Fri, 6 Jan 2006 08:20:28 +0000 (-0800) Subject: [PATCH] md: auto-correct correctable read errors in raid10 X-Git-Tag: v2.6.16-rc1~936^2~34 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4443ae10ca15d07922ceda622f03db8865fa3d13;p=linux-2.6 [PATCH] md: auto-correct correctable read errors in raid10 Largely just a cross-port from raid1. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 1fa70c34b7..64bb4ddc67 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -209,6 +209,7 @@ static void reschedule_retry(r10bio_t *r10_bio) spin_lock_irqsave(&conf->device_lock, flags); list_add(&r10_bio->retry_list, &conf->retry_list); + conf->nr_queued ++; spin_unlock_irqrestore(&conf->device_lock, flags); md_wakeup_thread(mddev->thread); @@ -254,9 +255,9 @@ static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int /* * this branch is our 'one mirror IO has finished' event handler: */ - if (!uptodate) - md_error(r10_bio->mddev, conf->mirrors[dev].rdev); - else + update_head_pos(slot, r10_bio); + + if (uptodate) { /* * Set R10BIO_Uptodate in our master bio, so that * we will return a good error code to the higher @@ -267,15 +268,8 @@ static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int * wait for the 'master' bio. */ set_bit(R10BIO_Uptodate, &r10_bio->state); - - update_head_pos(slot, r10_bio); - - /* - * we have only one bio on the read side - */ - if (uptodate) raid_end_bio_io(r10_bio); - else { + } else { /* * oops, read error: */ @@ -714,6 +708,33 @@ static void allow_barrier(conf_t *conf) wake_up(&conf->wait_barrier); } +static void freeze_array(conf_t *conf) +{ + /* stop syncio and normal IO and wait for everything to + * go quite. + * We increment barrier and nr_waiting, and then + * wait until barrier+nr_pending match nr_queued+2 + */ + spin_lock_irq(&conf->resync_lock); + conf->barrier++; + conf->nr_waiting++; + wait_event_lock_irq(conf->wait_barrier, + conf->barrier+conf->nr_pending == conf->nr_queued+2, + conf->resync_lock, + raid10_unplug(conf->mddev->queue)); + spin_unlock_irq(&conf->resync_lock); +} + +static void unfreeze_array(conf_t *conf) +{ + /* reverse the effect of the freeze */ + spin_lock_irq(&conf->resync_lock); + conf->barrier--; + conf->nr_waiting--; + wake_up(&conf->wait_barrier); + spin_unlock_irq(&conf->resync_lock); +} + static int make_request(request_queue_t *q, struct bio * bio) { mddev_t *mddev = q->queuedata; @@ -1338,6 +1359,7 @@ static void raid10d(mddev_t *mddev) break; r10_bio = list_entry(head->prev, r10bio_t, retry_list); list_del(head->prev); + conf->nr_queued--; spin_unlock_irqrestore(&conf->device_lock, flags); mddev = r10_bio->mddev; @@ -1350,6 +1372,78 @@ static void raid10d(mddev_t *mddev) unplug = 1; } else { int mirror; + /* we got a read error. Maybe the drive is bad. Maybe just + * the block and we can fix it. + * We freeze all other IO, and try reading the block from + * other devices. When we find one, we re-write + * and check it that fixes the read error. + * This is all done synchronously while the array is + * frozen. + */ + int sect = 0; /* Offset from r10_bio->sector */ + int sectors = r10_bio->sectors; + freeze_array(conf); + if (mddev->ro == 0) while(sectors) { + int s = sectors; + int sl = r10_bio->read_slot; + int success = 0; + + if (s > (PAGE_SIZE>>9)) + s = PAGE_SIZE >> 9; + + do { + int d = r10_bio->devs[sl].devnum; + rdev = conf->mirrors[d].rdev; + if (rdev && + test_bit(In_sync, &rdev->flags) && + sync_page_io(rdev->bdev, + r10_bio->devs[sl].addr + + sect + rdev->data_offset, + s<<9, + conf->tmppage, READ)) + success = 1; + else { + sl++; + if (sl == conf->copies) + sl = 0; + } + } while (!success && sl != r10_bio->read_slot); + + if (success) { + /* write it back and re-read */ + while (sl != r10_bio->read_slot) { + int d; + if (sl==0) + sl = conf->copies; + sl--; + d = r10_bio->devs[sl].devnum; + rdev = conf->mirrors[d].rdev; + if (rdev && + test_bit(In_sync, &rdev->flags)) { + if (sync_page_io(rdev->bdev, + r10_bio->devs[sl].addr + + sect + rdev->data_offset, + s<<9, conf->tmppage, WRITE) == 0 || + sync_page_io(rdev->bdev, + r10_bio->devs[sl].addr + + sect + rdev->data_offset, + s<<9, conf->tmppage, READ) == 0) { + /* Well, this device is dead */ + md_error(mddev, rdev); + } + } + } + } else { + /* Cannot read from anywhere -- bye bye array */ + md_error(mddev, conf->mirrors[r10_bio->devs[r10_bio->read_slot].devnum].rdev); + break; + } + sectors -= s; + sect += s; + } + + unfreeze_array(conf); + bio = r10_bio->devs[r10_bio->read_slot].bio; r10_bio->devs[r10_bio->read_slot].bio = NULL; bio_put(bio); @@ -1793,22 +1887,24 @@ static int run(mddev_t *mddev) * bookkeeping area. [whatever we allocate in run(), * should be freed in stop()] */ - conf = kmalloc(sizeof(conf_t), GFP_KERNEL); + conf = kzalloc(sizeof(conf_t), GFP_KERNEL); mddev->private = conf; if (!conf) { printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", mdname(mddev)); goto out; } - memset(conf, 0, sizeof(*conf)); - conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks, + conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks, GFP_KERNEL); if (!conf->mirrors) { printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", mdname(mddev)); goto out_free_conf; } - memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks); + + conf->tmppage = alloc_page(GFP_KERNEL); + if (!conf->tmppage) + goto out_free_conf; conf->near_copies = nc; conf->far_copies = fc; @@ -1918,6 +2014,7 @@ static int run(mddev_t *mddev) out_free_conf: if (conf->r10bio_pool) mempool_destroy(conf->r10bio_pool); + put_page(conf->tmppage); kfree(conf->mirrors); kfree(conf); mddev->private = NULL; diff --git a/include/linux/raid/raid10.h b/include/linux/raid/raid10.h index b660cbf628..dfa528385e 100644 --- a/include/linux/raid/raid10.h +++ b/include/linux/raid/raid10.h @@ -42,6 +42,7 @@ struct r10_private_data_s { spinlock_t resync_lock; int nr_pending; int nr_waiting; + int nr_queued; int barrier; sector_t next_resync; int fullsync; /* set to 1 if a full sync is needed, @@ -53,6 +54,7 @@ struct r10_private_data_s { mempool_t *r10bio_pool; mempool_t *r10buf_pool; + struct page *tmppage; }; typedef struct r10_private_data_s conf_t;