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md/raid10: simplify handle_read_error()
handle_read_error() duplicates a lot of the work that raid10_read_request() does, so it makes sense to just use that function. handle_read_error() relies on the same r10bio being re-used so that, in the case of a read-only array, setting IO_BLOCKED in r1bio->devs[].bio ensures read_balance() won't re-use that device. So when called from raid10_make_request() we clear that array, but not when called from handle_read_error(). Two parts of handle_read_error() that need to be preserved are the warning message it prints, so they are conditionally added to raid10_read_request(). If the failing rdev can be found, messages are printed. Otherwise they aren't. Not that as rdev_dec_pending() has already been called on the failing rdev, we need to use rcu_read_lock() to get a new reference from the conf. We only use this to get the name of the failing block device. With this change, we no longer need inc_pending(). Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
This commit is contained in:
NeilBrown
Shaohua Li
parent
fc9977dd06
commit
545250f248
@ -1008,15 +1008,6 @@ static void wait_barrier(struct r10conf *conf)
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spin_unlock_irq(&conf->resync_lock);
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}
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static void inc_pending(struct r10conf *conf)
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{
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/* The current request requires multiple r10_bio, so
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* we need to increment the pending count.
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*/
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WARN_ON(!atomic_read(&conf->nr_pending));
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atomic_inc(&conf->nr_pending);
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}
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static void allow_barrier(struct r10conf *conf)
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{
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if ((atomic_dec_and_test(&conf->nr_pending)) ||
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@ -1130,8 +1121,38 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
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int max_sectors;
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sector_t sectors;
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struct md_rdev *rdev;
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int slot;
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char b[BDEVNAME_SIZE];
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int slot = r10_bio->read_slot;
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struct md_rdev *err_rdev = NULL;
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gfp_t gfp = GFP_NOIO;
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if (r10_bio->devs[slot].rdev) {
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/*
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* This is an error retry, but we cannot
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* safely dereference the rdev in the r10_bio,
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* we must use the one in conf.
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* If it has already been disconnected (unlikely)
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* we lose the device name in error messages.
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*/
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int disk;
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/*
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* As we are blocking raid10, it is a little safer to
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* use __GFP_HIGH.
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*/
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gfp = GFP_NOIO | __GFP_HIGH;
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rcu_read_lock();
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disk = r10_bio->devs[slot].devnum;
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err_rdev = rcu_dereference(conf->mirrors[disk].rdev);
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if (err_rdev)
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bdevname(err_rdev->bdev, b);
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else {
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strcpy(b, "???");
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/* This never gets dereferenced */
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err_rdev = r10_bio->devs[slot].rdev;
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}
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rcu_read_unlock();
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}
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/*
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* Register the new request and wait if the reconstruction
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* thread has put up a bar for new requests.
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@ -1158,12 +1179,22 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
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rdev = read_balance(conf, r10_bio, &max_sectors);
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if (!rdev) {
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if (err_rdev) {
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pr_crit_ratelimited("md/raid10:%s: %s: unrecoverable I/O read error for block %llu\n",
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mdname(mddev), b,
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(unsigned long long)r10_bio->sector);
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}
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raid_end_bio_io(r10_bio);
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return;
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}
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if (err_rdev)
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pr_err_ratelimited("md/raid10:%s: %s: redirecting sector %llu to another mirror\n",
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mdname(mddev),
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bdevname(rdev->bdev, b),
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(unsigned long long)r10_bio->sector);
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if (max_sectors < bio_sectors(bio)) {
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struct bio *split = bio_split(bio, max_sectors,
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GFP_NOIO, conf->bio_split);
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gfp, conf->bio_split);
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bio_chain(split, bio);
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generic_make_request(bio);
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bio = split;
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@ -1172,7 +1203,7 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
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}
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slot = r10_bio->read_slot;
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read_bio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
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read_bio = bio_clone_fast(bio, gfp, mddev->bio_set);
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r10_bio->devs[slot].bio = read_bio;
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r10_bio->devs[slot].rdev = rdev;
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@ -1487,6 +1518,7 @@ static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
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r10_bio->mddev = mddev;
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r10_bio->sector = bio->bi_iter.bi_sector;
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r10_bio->state = 0;
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memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * conf->copies);
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if (bio_data_dir(bio) == READ)
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raid10_read_request(mddev, bio, r10_bio);
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@ -2556,9 +2588,6 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
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struct bio *bio;
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struct r10conf *conf = mddev->private;
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struct md_rdev *rdev = r10_bio->devs[slot].rdev;
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char b[BDEVNAME_SIZE];
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unsigned long do_sync;
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int max_sectors;
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dev_t bio_dev;
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sector_t bio_last_sector;
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@ -2571,7 +2600,6 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
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* frozen.
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*/
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bio = r10_bio->devs[slot].bio;
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bdevname(bio->bi_bdev, b);
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bio_dev = bio->bi_bdev->bd_dev;
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bio_last_sector = r10_bio->devs[slot].addr + rdev->data_offset + r10_bio->sectors;
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bio_put(bio);
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@ -2587,65 +2615,9 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
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md_error(mddev, rdev);
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rdev_dec_pending(rdev, mddev);
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read_more:
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rdev = read_balance(conf, r10_bio, &max_sectors);
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if (rdev == NULL) {
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pr_crit_ratelimited("md/raid10:%s: %s: unrecoverable I/O read error for block %llu\n",
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mdname(mddev), b,
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(unsigned long long)r10_bio->sector);
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raid_end_bio_io(r10_bio);
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return;
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}
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do_sync = (r10_bio->master_bio->bi_opf & REQ_SYNC);
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slot = r10_bio->read_slot;
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pr_err_ratelimited("md/raid10:%s: %s: redirecting sector %llu to another mirror\n",
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mdname(mddev),
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bdevname(rdev->bdev, b),
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(unsigned long long)r10_bio->sector);
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bio = bio_clone_fast(r10_bio->master_bio, GFP_NOIO, mddev->bio_set);
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bio_trim(bio, r10_bio->sector - bio->bi_iter.bi_sector, max_sectors);
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r10_bio->devs[slot].bio = bio;
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r10_bio->devs[slot].rdev = rdev;
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bio->bi_iter.bi_sector = r10_bio->devs[slot].addr
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+ choose_data_offset(r10_bio, rdev);
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bio->bi_bdev = rdev->bdev;
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bio_set_op_attrs(bio, REQ_OP_READ, do_sync);
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if (test_bit(FailFast, &rdev->flags) &&
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test_bit(R10BIO_FailFast, &r10_bio->state))
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bio->bi_opf |= MD_FAILFAST;
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bio->bi_private = r10_bio;
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bio->bi_end_io = raid10_end_read_request;
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trace_block_bio_remap(bdev_get_queue(bio->bi_bdev),
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bio, bio_dev,
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bio_last_sector - r10_bio->sectors);
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if (max_sectors < r10_bio->sectors) {
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/* Drat - have to split this up more */
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struct bio *mbio = r10_bio->master_bio;
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int sectors_handled =
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r10_bio->sector + max_sectors
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- mbio->bi_iter.bi_sector;
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r10_bio->sectors = max_sectors;
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bio_inc_remaining(mbio);
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inc_pending(conf);
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generic_make_request(bio);
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r10_bio = mempool_alloc(conf->r10bio_pool,
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GFP_NOIO);
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r10_bio->master_bio = mbio;
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r10_bio->sectors = bio_sectors(mbio) - sectors_handled;
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r10_bio->state = 0;
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set_bit(R10BIO_ReadError,
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&r10_bio->state);
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r10_bio->mddev = mddev;
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r10_bio->sector = mbio->bi_iter.bi_sector
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+ sectors_handled;
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goto read_more;
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} else
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generic_make_request(bio);
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allow_barrier(conf);
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r10_bio->state = 0;
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raid10_read_request(mddev, r10_bio->master_bio, r10_bio);
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}
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static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
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