From 7c4e06ff2b6a4c09638551dfde76f37f9fca5c0c Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 11 May 2011 14:53:17 +1000 Subject: [PATCH] md/raid10: some tidying up in fix_read_error Currently the rdev on which a read error happened could be removed before we perform the fix_error handling. This requires extra tests for NULL. So delay the rdev_dec_pending call until after the call to fix_read_error so that we can be sure that the rdev still exists. This allows an 'if' clause to be removed so the body gets re-indented back one level. Signed-off-by: NeilBrown --- drivers/md/raid10.c | 74 +++++++++++++++++++++------------------------ 1 file changed, 34 insertions(+), 40 deletions(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 8ea0acad606b..8e4f469a75b0 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -271,9 +271,10 @@ static void raid10_end_read_request(struct bio *bio, int error) */ set_bit(R10BIO_Uptodate, &r10_bio->state); raid_end_bio_io(r10_bio); + rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); } else { /* - * oops, read error: + * oops, read error - keep the refcount on the rdev */ char b[BDEVNAME_SIZE]; if (printk_ratelimit()) @@ -282,8 +283,6 @@ static void raid10_end_read_request(struct bio *bio, int error) bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector); reschedule_retry(r10_bio); } - - rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); } static void raid10_end_write_request(struct bio *bio, int error) @@ -1438,40 +1437,33 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) int max_read_errors = atomic_read(&mddev->max_corr_read_errors); int d = r10_bio->devs[r10_bio->read_slot].devnum; - rcu_read_lock(); - rdev = rcu_dereference(conf->mirrors[d].rdev); - if (rdev) { /* If rdev is not NULL */ - char b[BDEVNAME_SIZE]; - int cur_read_error_count = 0; + /* still own a reference to this rdev, so it cannot + * have been cleared recently. + */ + rdev = conf->mirrors[d].rdev; - bdevname(rdev->bdev, b); + if (test_bit(Faulty, &rdev->flags)) + /* drive has already been failed, just ignore any + more fix_read_error() attempts */ + return; - if (test_bit(Faulty, &rdev->flags)) { - rcu_read_unlock(); - /* drive has already been failed, just ignore any - more fix_read_error() attempts */ - return; - } + check_decay_read_errors(mddev, rdev); + atomic_inc(&rdev->read_errors); + if (atomic_read(&rdev->read_errors) > max_read_errors) { + char b[BDEVNAME_SIZE]; + bdevname(rdev->bdev, b); - check_decay_read_errors(mddev, rdev); - atomic_inc(&rdev->read_errors); - cur_read_error_count = atomic_read(&rdev->read_errors); - if (cur_read_error_count > max_read_errors) { - rcu_read_unlock(); - printk(KERN_NOTICE - "md/raid10:%s: %s: Raid device exceeded " - "read_error threshold " - "[cur %d:max %d]\n", - mdname(mddev), - b, cur_read_error_count, max_read_errors); - printk(KERN_NOTICE - "md/raid10:%s: %s: Failing raid " - "device\n", mdname(mddev), b); - md_error(mddev, conf->mirrors[d].rdev); - return; - } + printk(KERN_NOTICE + "md/raid10:%s: %s: Raid device exceeded " + "read_error threshold [cur %d:max %d]\n", + mdname(mddev), b, + atomic_read(&rdev->read_errors), max_read_errors); + printk(KERN_NOTICE + "md/raid10:%s: %s: Failing raid device\n", + mdname(mddev), b); + md_error(mddev, conf->mirrors[d].rdev); + return; } - rcu_read_unlock(); while(sectors) { int s = sectors; @@ -1540,8 +1532,8 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) "write failed" " (%d sectors at %llu on %s)\n", mdname(mddev), s, - (unsigned long long)(sect+ - rdev->data_offset), + (unsigned long long)( + sect + rdev->data_offset), bdevname(rdev->bdev, b)); printk(KERN_NOTICE "md/raid10:%s: %s: failing " "drive\n", @@ -1577,8 +1569,8 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) "corrected sectors" " (%d sectors at %llu on %s)\n", mdname(mddev), s, - (unsigned long long)(sect+ - rdev->data_offset), + (unsigned long long)( + sect + rdev->data_offset), bdevname(rdev->bdev, b)); printk(KERN_NOTICE "md/raid10:%s: %s: failing drive\n", mdname(mddev), @@ -1590,8 +1582,8 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) "md/raid10:%s: read error corrected" " (%d sectors at %llu on %s)\n", mdname(mddev), s, - (unsigned long long)(sect+ - rdev->data_offset), + (unsigned long long)( + sect + rdev->data_offset), bdevname(rdev->bdev, b)); } @@ -1641,7 +1633,8 @@ static void raid10d(mddev_t *mddev) else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) recovery_request_write(mddev, r10_bio); else { - int mirror; + int slot = r10_bio->read_slot; + int mirror = r10_bio->devs[slot].devnum; /* 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 @@ -1655,6 +1648,7 @@ static void raid10d(mddev_t *mddev) fix_read_error(conf, mddev, r10_bio); unfreeze_array(conf); } + rdev_dec_pending(conf->mirrors[mirror].rdev, mddev); bio = r10_bio->devs[r10_bio->read_slot].bio; r10_bio->devs[r10_bio->read_slot].bio = -- GitLab