From e5aea7b49f2b1fd01f35ca7abeb76f5c56128a55 Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Fri, 13 Jun 2014 14:47:24 +0100 Subject: [PATCH] dm thin: relax external origin size constraints Track the size of any external origin. Previously the external origin's size had to be a multiple of the thin-pool's block size, that is no longer a requirement. In addition, snapshots that are larger than the external origin are now supported. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer --- drivers/md/dm-thin.c | 158 +++++++++++++++++++++++++++++++------------ 1 file changed, 115 insertions(+), 43 deletions(-) diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 4c9a3b5f4ff1..0e844a5eca8f 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -227,6 +227,7 @@ struct thin_c { struct list_head list; struct dm_dev *pool_dev; struct dm_dev *origin_dev; + sector_t origin_size; dm_thin_id dev_id; struct pool *pool; @@ -590,31 +591,31 @@ static void __complete_mapping_preparation(struct dm_thin_new_mapping *m) } } -static void copy_complete(int read_err, unsigned long write_err, void *context) +static void complete_mapping_preparation(struct dm_thin_new_mapping *m) { unsigned long flags; - struct dm_thin_new_mapping *m = context; struct pool *pool = m->tc->pool; - m->err = read_err || write_err ? -EIO : 0; - spin_lock_irqsave(&pool->lock, flags); __complete_mapping_preparation(m); spin_unlock_irqrestore(&pool->lock, flags); } +static void copy_complete(int read_err, unsigned long write_err, void *context) +{ + struct dm_thin_new_mapping *m = context; + + m->err = read_err || write_err ? -EIO : 0; + complete_mapping_preparation(m); +} + static void overwrite_endio(struct bio *bio, int err) { - unsigned long flags; struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); struct dm_thin_new_mapping *m = h->overwrite_mapping; - struct pool *pool = m->tc->pool; m->err = err; - - spin_lock_irqsave(&pool->lock, flags); - __complete_mapping_preparation(m); - spin_unlock_irqrestore(&pool->lock, flags); + complete_mapping_preparation(m); } /*----------------------------------------------------------------*/ @@ -824,10 +825,31 @@ static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool) return m; } +static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m, + sector_t begin, sector_t end) +{ + int r; + struct dm_io_region to; + + to.bdev = tc->pool_dev->bdev; + to.sector = begin; + to.count = end - begin; + + r = dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m); + if (r < 0) { + DMERR_LIMIT("dm_kcopyd_zero() failed"); + copy_complete(1, 1, m); + } +} + +/* + * A partial copy also needs to zero the uncopied region. + */ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, struct dm_dev *origin, dm_block_t data_origin, dm_block_t data_dest, - struct dm_bio_prison_cell *cell, struct bio *bio) + struct dm_bio_prison_cell *cell, struct bio *bio, + sector_t len) { int r; struct pool *pool = tc->pool; @@ -838,10 +860,15 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, m->data_block = data_dest; m->cell = cell; + /* + * quiesce action + copy action + an extra reference held for the + * duration of this function (we may need to inc later for a + * partial zero). + */ + atomic_set(&m->prepare_actions, 3); + if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list)) - atomic_set(&m->prepare_actions, 1); /* copy only */ - else - atomic_set(&m->prepare_actions, 2); /* quiesce + copy */ + complete_mapping_preparation(m); /* already quiesced */ /* * IO to pool_dev remaps to the pool target's data_dev. @@ -862,20 +889,38 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, from.bdev = origin->bdev; from.sector = data_origin * pool->sectors_per_block; - from.count = pool->sectors_per_block; + from.count = len; to.bdev = tc->pool_dev->bdev; to.sector = data_dest * pool->sectors_per_block; - to.count = pool->sectors_per_block; + to.count = len; r = dm_kcopyd_copy(pool->copier, &from, 1, &to, 0, copy_complete, m); if (r < 0) { - mempool_free(m, pool->mapping_pool); DMERR_LIMIT("dm_kcopyd_copy() failed"); - cell_error(pool, cell); + copy_complete(1, 1, m); + + /* + * We allow the zero to be issued, to simplify the + * error path. Otherwise we'd need to start + * worrying about decrementing the prepare_actions + * counter. + */ + } + + /* + * Do we need to zero a tail region? + */ + if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) { + atomic_inc(&m->prepare_actions); + ll_zero(tc, m, + data_dest * pool->sectors_per_block + len, + (data_dest + 1) * pool->sectors_per_block); } } + + complete_mapping_preparation(m); /* drop our ref */ } static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block, @@ -883,15 +928,8 @@ static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block, struct dm_bio_prison_cell *cell, struct bio *bio) { schedule_copy(tc, virt_block, tc->pool_dev, - data_origin, data_dest, cell, bio); -} - -static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block, - dm_block_t data_dest, - struct dm_bio_prison_cell *cell, struct bio *bio) -{ - schedule_copy(tc, virt_block, tc->origin_dev, - virt_block, data_dest, cell, bio); + data_origin, data_dest, cell, bio, + tc->pool->sectors_per_block); } static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, @@ -923,21 +961,33 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); inc_all_io_entry(pool, bio); remap_and_issue(tc, bio, data_block); - } else { - int r; - struct dm_io_region to; - to.bdev = tc->pool_dev->bdev; - to.sector = data_block * pool->sectors_per_block; - to.count = pool->sectors_per_block; + } else + ll_zero(tc, m, + data_block * pool->sectors_per_block, + (data_block + 1) * pool->sectors_per_block); +} - r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m); - if (r < 0) { - mempool_free(m, pool->mapping_pool); - DMERR_LIMIT("dm_kcopyd_zero() failed"); - cell_error(pool, cell); - } - } +static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block, + dm_block_t data_dest, + struct dm_bio_prison_cell *cell, struct bio *bio) +{ + struct pool *pool = tc->pool; + sector_t virt_block_begin = virt_block * pool->sectors_per_block; + sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block; + + if (virt_block_end <= tc->origin_size) + schedule_copy(tc, virt_block, tc->origin_dev, + virt_block, data_dest, cell, bio, + pool->sectors_per_block); + + else if (virt_block_begin < tc->origin_size) + schedule_copy(tc, virt_block, tc->origin_dev, + virt_block, data_dest, cell, bio, + tc->origin_size - virt_block_begin); + + else + schedule_zero(tc, virt_block, data_dest, cell, bio); } /* @@ -1319,7 +1369,18 @@ static void process_bio(struct thin_c *tc, struct bio *bio) inc_all_io_entry(pool, bio); cell_defer_no_holder(tc, cell); - remap_to_origin_and_issue(tc, bio); + if (bio_end_sector(bio) <= tc->origin_size) + remap_to_origin_and_issue(tc, bio); + + else if (bio->bi_iter.bi_sector < tc->origin_size) { + zero_fill_bio(bio); + bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT; + remap_to_origin_and_issue(tc, bio); + + } else { + zero_fill_bio(bio); + bio_endio(bio, 0); + } } else provision_block(tc, bio, block, cell); break; @@ -3145,7 +3206,7 @@ static struct target_type pool_target = { .name = "thin-pool", .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | DM_TARGET_IMMUTABLE, - .version = {1, 12, 0}, + .version = {1, 13, 0}, .module = THIS_MODULE, .ctr = pool_ctr, .dtr = pool_dtr, @@ -3404,6 +3465,16 @@ static void thin_postsuspend(struct dm_target *ti) noflush_work(tc, do_noflush_stop); } +static int thin_preresume(struct dm_target *ti) +{ + struct thin_c *tc = ti->private; + + if (tc->origin_dev) + tc->origin_size = get_dev_size(tc->origin_dev->bdev); + + return 0; +} + /* * */ @@ -3486,12 +3557,13 @@ static int thin_iterate_devices(struct dm_target *ti, static struct target_type thin_target = { .name = "thin", - .version = {1, 12, 0}, + .version = {1, 13, 0}, .module = THIS_MODULE, .ctr = thin_ctr, .dtr = thin_dtr, .map = thin_map, .end_io = thin_endio, + .preresume = thin_preresume, .presuspend = thin_presuspend, .postsuspend = thin_postsuspend, .status = thin_status, -- 2.39.2