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Commit 7c4e06ff authored by NeilBrown's avatar NeilBrown
Browse files

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: default avatarNeilBrown <neilb@suse.de>
parent af6d7b76

drivers/md/raid10.c

+34 −40
Original line number Diff line number Diff line
@@ -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;



		bdevname(rdev->bdev, b);

	/* still own a reference to this rdev, so it cannot

	 * have been cleared recently.

	 */

	rdev = conf->mirrors[d].rdev;



		if (test_bit(Faulty, &rdev->flags)) {

			rcu_read_unlock();

	if (test_bit(Faulty, &rdev->flags))

		/* 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);

		cur_read_error_count = atomic_read(&rdev->read_errors);

		if (cur_read_error_count > max_read_errors) {

			rcu_read_unlock();

	if (atomic_read(&rdev->read_errors) > max_read_errors) {

		char b[BDEVNAME_SIZE];

		bdevname(rdev->bdev, b);



		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);

		       "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/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 =