raid10 splits requests in two different ways for two different
reasons.
First, bio_split() is used to ensure the bio fits with a chunk.
Second, multiple r10bio structures are allocated to represent the
different sections that need to go to different devices, to avoid
known bad blocks.
This can be simplified to just use bio_split() once, and not to use
multiple r10bios.
We delay the split until we know a maximum bio size that can
be handled with a single r10bio, and then split the bio and queue
the remainder for later handling.
As with raid1, we allocate a new bio_set to help with the splitting.
It is not correct to use fs_bio_set in a device driver.
Signed-off-by: NeilBrown <neilb@xxxxxxxx>
---
drivers/md/raid10.c | 164 ++++++++++++++++-----------------------------------
drivers/md/raid10.h | 1
2 files changed, 51 insertions(+), 114 deletions(-)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 0f13d57ef646..ff02c058dbdd 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1127,7 +1127,6 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
struct bio *read_bio;
const int op = bio_op(bio);
const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
- int sectors_handled;
int max_sectors;
sector_t sectors;
struct md_rdev *rdev;
@@ -1140,7 +1139,7 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
*/
wait_barrier(conf);
- sectors = bio_sectors(bio);
+ sectors = r10_bio->sectors;
while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
bio->bi_iter.bi_sector < conf->reshape_progress &&
bio->bi_iter.bi_sector + sectors > conf->reshape_progress) {
@@ -1157,17 +1156,23 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
wait_barrier(conf);
}
-read_again:
rdev = read_balance(conf, r10_bio, &max_sectors);
if (!rdev) {
raid_end_bio_io(r10_bio);
return;
}
+ if (max_sectors < bio_sectors(bio)) {
+ struct bio *split = bio_split(bio, max_sectors,
+ GFP_NOIO, conf->bio_split);
+ bio_chain(split, bio);
+ generic_make_request(bio);
+ bio = split;
+ r10_bio->master_bio = bio;
+ r10_bio->sectors = max_sectors;
+ }
slot = r10_bio->read_slot;
read_bio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
- bio_trim(read_bio, r10_bio->sector - bio->bi_iter.bi_sector,
- max_sectors);
r10_bio->devs[slot].bio = read_bio;
r10_bio->devs[slot].rdev = rdev;
@@ -1186,40 +1191,13 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
trace_block_bio_remap(bdev_get_queue(read_bio->bi_bdev),
read_bio, disk_devt(mddev->gendisk),
r10_bio->sector);
- if (max_sectors < r10_bio->sectors) {
- /*
- * Could not read all from this device, so we will need another
- * r10_bio.
- */
- sectors_handled = (r10_bio->sector + max_sectors
- - bio->bi_iter.bi_sector);
- r10_bio->sectors = max_sectors;
- inc_pending(conf);
- bio_inc_remaining(bio);
- /*
- * Cannot call generic_make_request directly as that will be
- * queued in __generic_make_request and subsequent
- * mempool_alloc might block waiting for it. so hand bio over
- * to raid10d.
- */
- reschedule_retry(r10_bio);
-
- r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
-
- r10_bio->master_bio = bio;
- r10_bio->sectors = bio_sectors(bio) - sectors_handled;
- r10_bio->state = 0;
- r10_bio->mddev = mddev;
- r10_bio->sector = bio->bi_iter.bi_sector + sectors_handled;
- goto read_again;
- } else
- generic_make_request(read_bio);
+ generic_make_request(read_bio);
return;
}
static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
struct bio *bio, bool replacement,
- int n_copy, int max_sectors)
+ int n_copy)
{
const int op = bio_op(bio);
const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
@@ -1243,7 +1221,6 @@ static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
rdev = conf->mirrors[devnum].rdev;
mbio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
- bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector, max_sectors);
if (replacement)
r10_bio->devs[n_copy].repl_bio = mbio;
else
@@ -1294,7 +1271,6 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
int i;
struct md_rdev *blocked_rdev;
sector_t sectors;
- int sectors_handled;
int max_sectors;
md_write_start(mddev, bio);
@@ -1306,7 +1282,7 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
*/
wait_barrier(conf);
- sectors = bio_sectors(bio);
+ sectors = r10_bio->sectors;
while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
bio->bi_iter.bi_sector < conf->reshape_progress &&
bio->bi_iter.bi_sector + sectors > conf->reshape_progress) {
@@ -1476,44 +1452,29 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
if (max_sectors < r10_bio->sectors)
r10_bio->sectors = max_sectors;
- sectors_handled = r10_bio->sector + max_sectors -
- bio->bi_iter.bi_sector;
+
+ if (r10_bio->sectors < bio_sectors(bio)) {
+ struct bio *split = bio_split(bio, r10_bio->sectors,
+ GFP_NOIO, conf->bio_split);
+ bio_chain(split, bio);
+ generic_make_request(bio);
+ bio = split;
+ r10_bio->master_bio = bio;
+ }
atomic_set(&r10_bio->remaining, 1);
bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
for (i = 0; i < conf->copies; i++) {
if (r10_bio->devs[i].bio)
- raid10_write_one_disk(mddev, r10_bio, bio, false,
- i, max_sectors);
+ raid10_write_one_disk(mddev, r10_bio, bio, false, i);
if (r10_bio->devs[i].repl_bio)
- raid10_write_one_disk(mddev, r10_bio, bio, true,
- i, max_sectors);
- }
-
- /* Don't remove the bias on 'remaining' (one_write_done) until
- * after checking if we need to go around again.
- */
-
- if (sectors_handled < bio_sectors(bio)) {
- /* We need another r10_bio and it needs to be counted */
- inc_pending(conf);
- bio_inc_remaining(bio);
- one_write_done(r10_bio);
- r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
-
- r10_bio->master_bio = bio;
- r10_bio->sectors = bio_sectors(bio) - sectors_handled;
-
- r10_bio->mddev = mddev;
- r10_bio->sector = bio->bi_iter.bi_sector + sectors_handled;
- r10_bio->state = 0;
- goto retry_write;
+ raid10_write_one_disk(mddev, r10_bio, bio, true, i);
}
one_write_done(r10_bio);
}
-static void __make_request(struct mddev *mddev, struct bio *bio)
+static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
{
struct r10conf *conf = mddev->private;
struct r10bio *r10_bio;
@@ -1521,7 +1482,7 @@ static void __make_request(struct mddev *mddev, struct bio *bio)
r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
r10_bio->master_bio = bio;
- r10_bio->sectors = bio_sectors(bio);
+ r10_bio->sectors = sectors;
r10_bio->mddev = mddev;
r10_bio->sector = bio->bi_iter.bi_sector;
@@ -1538,54 +1499,26 @@ static void raid10_make_request(struct mddev *mddev, struct bio *bio)
struct r10conf *conf = mddev->private;
sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
int chunk_sects = chunk_mask + 1;
-
- struct bio *split;
+ int sectors = bio_sectors(bio);
if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
md_flush_request(mddev, bio);
return;
}
- do {
-
- /*
- * If this request crosses a chunk boundary, we need to split
- * it.
- */
- if (unlikely((bio->bi_iter.bi_sector & chunk_mask) +
- bio_sectors(bio) > chunk_sects
- && (conf->geo.near_copies < conf->geo.raid_disks
- || conf->prev.near_copies <
- conf->prev.raid_disks))) {
- split = bio_split(bio, chunk_sects -
- (bio->bi_iter.bi_sector &
- (chunk_sects - 1)),
- GFP_NOIO, fs_bio_set);
- bio_chain(split, bio);
- } else {
- split = bio;
- }
-
- /*
- * If a bio is splitted, the first part of bio will pass
- * barrier but the bio is queued in current->bio_list (see
- * generic_make_request). If there is a raise_barrier() called
- * here, the second part of bio can't pass barrier. But since
- * the first part bio isn't dispatched to underlaying disks
- * yet, the barrier is never released, hence raise_barrier will
- * alays wait. We have a deadlock.
- * Note, this only happens in read path. For write path, the
- * first part of bio is dispatched in a schedule() call
- * (because of blk plug) or offloaded to raid10d.
- * Quitting from the function immediately can change the bio
- * order queued in bio_list and avoid the deadlock.
- */
- __make_request(mddev, split);
- if (split != bio && bio_data_dir(bio) == READ) {
- generic_make_request(bio);
- break;
- }
- } while (split != bio);
+ /*
+ * If this request crosses a chunk boundary, we need to split
+ * it.
+ */
+ if (unlikely((bio->bi_iter.bi_sector & chunk_mask) +
+ sectors > chunk_sects
+ && (conf->geo.near_copies < conf->geo.raid_disks
+ || conf->prev.near_copies <
+ conf->prev.raid_disks)))
+ sectors = chunk_sects -
+ (bio->bi_iter.bi_sector &
+ (chunk_sects - 1));
+ __make_request(mddev, bio, sectors);
/* In case raid10d snuck in to freeze_array */
wake_up(&conf->wait_barrier);
@@ -2873,13 +2806,8 @@ static void raid10d(struct md_thread *thread)
recovery_request_write(mddev, r10_bio);
else if (test_bit(R10BIO_ReadError, &r10_bio->state))
handle_read_error(mddev, r10_bio);
- else {
- /* just a partial read to be scheduled from a
- * separate context
- */
- int slot = r10_bio->read_slot;
- generic_make_request(r10_bio->devs[slot].bio);
- }
+ else
+ WARN_ON_ONCE(1);
cond_resched();
if (mddev->sb_flags & ~(1<<MD_SB_CHANGE_PENDING))
@@ -3652,6 +3580,10 @@ static struct r10conf *setup_conf(struct mddev *mddev)
if (!conf->r10bio_pool)
goto out;
+ conf->bio_split = bioset_create(BIO_POOL_SIZE, 0);
+ if (!conf->bio_split)
+ goto out;
+
calc_sectors(conf, mddev->dev_sectors);
if (mddev->reshape_position == MaxSector) {
conf->prev = conf->geo;
@@ -3689,6 +3621,8 @@ static struct r10conf *setup_conf(struct mddev *mddev)
mempool_destroy(conf->r10bio_pool);
kfree(conf->mirrors);
safe_put_page(conf->tmppage);
+ if (conf->bio_split)
+ bioset_free(conf->bio_split);
kfree(conf);
}
return ERR_PTR(err);
@@ -3898,6 +3832,8 @@ static void raid10_free(struct mddev *mddev, void *priv)
kfree(conf->mirrors);
kfree(conf->mirrors_old);
kfree(conf->mirrors_new);
+ if (conf->bio_split)
+ bioset_free(conf->bio_split);
kfree(conf);
}
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index 3162615e57bd..735ce1a3d260 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -82,6 +82,7 @@ struct r10conf {
mempool_t *r10bio_pool;
mempool_t *r10buf_pool;
struct page *tmppage;
+ struct bio_set *bio_split;
/* When taking over an array from a different personality, we store
* the new thread here until we fully activate the array.
--
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