md: raid0 :Enables chunk size other than powers of 2.
Maintain two flows, one for pow2 chunk sizes (which uses masks and shift), and a flow for the general case (which uses sector_div). This is for the sake of performance. - introduce map_sector and is_io_in_chunk_boundary to encapsulate those two flows better for raid0_make_request - fix blk_mergeable to support the two flows. Signed-off-by: raziebe@gmail.com Signed-off-by: NeilBrown <neilb@suse.de>
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@ -273,7 +273,12 @@ static int raid0_mergeable_bvec(struct request_queue *q,
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unsigned int chunk_sectors = mddev->chunk_size >> 9;
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unsigned int chunk_sectors = mddev->chunk_size >> 9;
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unsigned int bio_sectors = bvm->bi_size >> 9;
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unsigned int bio_sectors = bvm->bi_size >> 9;
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max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
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if (is_power_of_2(mddev->chunk_size))
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max = (chunk_sectors - ((sector & (chunk_sectors-1))
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+ bio_sectors)) << 9;
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else
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max = (chunk_sectors - (sector_div(sector, chunk_sectors)
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+ bio_sectors)) << 9;
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if (max < 0) max = 0; /* bio_add cannot handle a negative return */
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if (max < 0) max = 0; /* bio_add cannot handle a negative return */
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if (max <= biovec->bv_len && bio_sectors == 0)
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if (max <= biovec->bv_len && bio_sectors == 0)
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return biovec->bv_len;
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return biovec->bv_len;
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@ -299,9 +304,8 @@ static int raid0_run(mddev_t *mddev)
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{
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{
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int ret;
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int ret;
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if (mddev->chunk_size == 0 ||
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if (mddev->chunk_size == 0) {
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!is_power_of_2(mddev->chunk_size)) {
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printk(KERN_ERR "md/raid0: chunk size must be set.\n");
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printk(KERN_ERR "md/raid0: chunk size must be a power of 2.\n");
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return -EINVAL;
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return -EINVAL;
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}
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}
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blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9);
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blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9);
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@ -367,15 +371,65 @@ static struct strip_zone *find_zone(struct raid0_private_data *conf,
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BUG();
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BUG();
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}
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}
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static int raid0_make_request (struct request_queue *q, struct bio *bio)
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/*
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* remaps the bio to the target device. we separate two flows.
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* power 2 flow and a general flow for the sake of perfromance
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*/
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static mdk_rdev_t *map_sector(mddev_t *mddev, struct strip_zone *zone,
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sector_t sector, sector_t *sector_offset)
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{
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unsigned int sect_in_chunk;
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sector_t chunk;
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raid0_conf_t *conf = mddev->private;
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unsigned int chunk_sects = mddev->chunk_size >> 9;
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if (is_power_of_2(mddev->chunk_size)) {
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int chunksect_bits = ffz(~chunk_sects);
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/* find the sector offset inside the chunk */
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sect_in_chunk = sector & (chunk_sects - 1);
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sector >>= chunksect_bits;
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/* chunk in zone */
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chunk = *sector_offset;
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/* quotient is the chunk in real device*/
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sector_div(chunk, zone->nb_dev << chunksect_bits);
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} else{
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sect_in_chunk = sector_div(sector, chunk_sects);
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chunk = *sector_offset;
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sector_div(chunk, chunk_sects * zone->nb_dev);
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}
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/*
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* position the bio over the real device
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* real sector = chunk in device + starting of zone
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* + the position in the chunk
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*/
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*sector_offset = (chunk * chunk_sects) + sect_in_chunk;
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return conf->devlist[(zone - conf->strip_zone)*mddev->raid_disks
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+ sector_div(sector, zone->nb_dev)];
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}
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/*
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* Is io distribute over 1 or more chunks ?
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*/
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static inline int is_io_in_chunk_boundary(mddev_t *mddev,
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unsigned int chunk_sects, struct bio *bio)
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{
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if (likely(is_power_of_2(mddev->chunk_size))) {
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return chunk_sects >= ((bio->bi_sector & (chunk_sects-1))
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+ (bio->bi_size >> 9));
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} else{
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sector_t sector = bio->bi_sector;
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return chunk_sects >= (sector_div(sector, chunk_sects)
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+ (bio->bi_size >> 9));
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}
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}
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static int raid0_make_request(struct request_queue *q, struct bio *bio)
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{
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{
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mddev_t *mddev = q->queuedata;
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mddev_t *mddev = q->queuedata;
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unsigned int sect_in_chunk, chunksect_bits, chunk_sects;
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unsigned int chunk_sects;
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raid0_conf_t *conf = mddev->private;
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sector_t sector_offset;
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struct strip_zone *zone;
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struct strip_zone *zone;
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mdk_rdev_t *tmp_dev;
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mdk_rdev_t *tmp_dev;
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sector_t chunk;
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sector_t sector, rsect, sector_offset;
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const int rw = bio_data_dir(bio);
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const int rw = bio_data_dir(bio);
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int cpu;
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int cpu;
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@ -391,10 +445,8 @@ static int raid0_make_request (struct request_queue *q, struct bio *bio)
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part_stat_unlock();
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part_stat_unlock();
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chunk_sects = mddev->chunk_size >> 9;
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chunk_sects = mddev->chunk_size >> 9;
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chunksect_bits = ffz(~chunk_sects);
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if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) {
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sector = bio->bi_sector;
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sector_t sector = bio->bi_sector;
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if (unlikely(chunk_sects < (bio->bi_sector & (chunk_sects - 1)) + (bio->bi_size >> 9))) {
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struct bio_pair *bp;
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struct bio_pair *bp;
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/* Sanity check -- queue functions should prevent this happening */
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/* Sanity check -- queue functions should prevent this happening */
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if (bio->bi_vcnt != 1 ||
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if (bio->bi_vcnt != 1 ||
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@ -403,7 +455,12 @@ static int raid0_make_request (struct request_queue *q, struct bio *bio)
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/* This is a one page bio that upper layers
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/* This is a one page bio that upper layers
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* refuse to split for us, so we need to split it.
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* refuse to split for us, so we need to split it.
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*/
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*/
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bp = bio_split(bio, chunk_sects - (bio->bi_sector & (chunk_sects - 1)));
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if (likely(is_power_of_2(mddev->chunk_size)))
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bp = bio_split(bio, chunk_sects - (sector &
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(chunk_sects-1)));
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else
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bp = bio_split(bio, chunk_sects -
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sector_div(sector, chunk_sects));
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if (raid0_make_request(q, &bp->bio1))
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if (raid0_make_request(q, &bp->bio1))
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generic_make_request(&bp->bio1);
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generic_make_request(&bp->bio1);
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if (raid0_make_request(q, &bp->bio2))
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if (raid0_make_request(q, &bp->bio2))
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@ -412,24 +469,14 @@ static int raid0_make_request (struct request_queue *q, struct bio *bio)
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bio_pair_release(bp);
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bio_pair_release(bp);
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return 0;
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return 0;
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}
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}
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sector_offset = sector;
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zone = find_zone(conf, §or_offset);
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sect_in_chunk = bio->bi_sector & (chunk_sects - 1);
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{
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sector_t x = sector_offset >> chunksect_bits;
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sector_div(x, zone->nb_dev);
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sector_offset = bio->bi_sector;
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chunk = x;
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zone = find_zone(mddev->private, §or_offset);
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tmp_dev = map_sector(mddev, zone, bio->bi_sector,
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x = sector >> chunksect_bits;
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§or_offset);
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tmp_dev = conf->devlist[(zone - conf->strip_zone)*mddev->raid_disks
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+ sector_div(x, zone->nb_dev)];
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}
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rsect = (chunk << chunksect_bits) + zone->dev_start + sect_in_chunk;
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bio->bi_bdev = tmp_dev->bdev;
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bio->bi_bdev = tmp_dev->bdev;
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bio->bi_sector = rsect + tmp_dev->data_offset;
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bio->bi_sector = sector_offset + zone->dev_start +
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tmp_dev->data_offset;
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/*
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/*
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* Let the main block layer submit the IO and resolve recursion:
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* Let the main block layer submit the IO and resolve recursion:
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*/
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*/
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