| Message ID | 20230414000219.92640-3-sarthakkukreti@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3,1/3] block: Introduce provisioning primitives | expand |
On Fri, Apr 14 2023 at 9:32P -0400, Joe Thornber <thornber@redhat.com> wrote: > On Fri, Apr 14, 2023 at 7:52 AM Sarthak Kukreti <sarthakkukreti@chromium.org> > wrote: > > > Add support to dm devices for REQ_OP_PROVISION. The default mode > > is to passthrough the request to the underlying device, if it > > supports it. dm-thinpool uses the provision request to provision > > blocks for a dm-thin device. dm-thinpool currently does not > > pass through REQ_OP_PROVISION to underlying devices. > > > > For shared blocks, provision requests will break sharing and copy the > > contents of the entire block. > > > > I see two issue with this patch: > > i) You use get_bio_block_range() to see which blocks the provision bio > covers. But this function only returns > complete blocks that are covered (it was designed for discard). Unlike > discard, provision is not a hint so those > partial blocks will need to be provisioned too. > > ii) You are setting off multiple dm_thin_new_mapping operations in flight > at once. Each of these receives > the same virt_cell and frees it when it completes. So I think we have > multiple frees occuring? In addition you also > release the cell yourself in process_provision_cell(). Fixing this is not > trivial, you'll need to reference count the cells, > and aggregate the mapping operation results. > > I think it would be far easier to restrict the size of the provision bio to > be no bigger than one thinp block (as we do for normal io). This way dm > core can split the bios, chain the child bios rather than having to > reference count mapping ops, and aggregate the results. I happened to be looking at implementing WRITE_ZEROES support for DM thinp yesterday and reached the same conclussion relative to it (both of Joe's points above, for me "ii)" was: the dm-bio-prison-v1 range locking we do for discards needs work for other types of IO). We can work to make REQ_OP_PROVISION spanning multiple thinp blocks possible as follow-on optimization; but in the near-term DM thinp needs REQ_OP_PROVISION to be split on a thinp block boundary. This splitting can be assisted by block core in terms of a new 'provision_granularity' (which for thinp, it'd be set to the thinp blocksize). But I don't know that we need to go that far (I'm thinking its fine to have DM do the splitting it needs and only elevate related code to block core if/when needed in the future). DM core can take on conditionally imposing its max_io_len() to handle splitting REQ_OP_PROVISION as needed on a per-target basis. This DM core commit I've staged for 6.4 makes this quite a simple change: https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-6.4&id=13f6facf3faeed34ca381aef4c9b153c7aed3972 So please rebase on linux-dm.git's dm-6.4 branch, and for REQ_OP_PROVISION dm.c:__process_abnormal_io() you'd add this: case REQ_OP_PROVISION: num_bios = ti->num_provision_bios; if (ti->max_provision_granularity) max_granularity = limits->max_provision_sectors; break; I'll reply again later today (to patch 2's actual code changes), because I caught at least one other thing worth mentioning. Thanks, Mike
On Thu, Apr 13 2023 at 8:02P -0400, Sarthak Kukreti <sarthakkukreti@chromium.org> wrote: > Add support to dm devices for REQ_OP_PROVISION. The default mode > is to passthrough the request to the underlying device, if it > supports it. dm-thinpool uses the provision request to provision > blocks for a dm-thin device. dm-thinpool currently does not > pass through REQ_OP_PROVISION to underlying devices. > > For shared blocks, provision requests will break sharing and copy the > contents of the entire block. > > Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org> > --- > drivers/md/dm-crypt.c | 4 +- > drivers/md/dm-linear.c | 1 + > drivers/md/dm-snap.c | 7 +++ Have you tested REQ_OP_PROVISION with these targets? Just want to make sure you have an explicit need (and vested interest) for them passing through REQ_OP_PROVISION. > diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c > index 2055a758541d..5985343384a7 100644 > --- a/drivers/md/dm-table.c > +++ b/drivers/md/dm-table.c > @@ -1850,6 +1850,26 @@ static bool dm_table_supports_write_zeroes(struct dm_table *t) > return true; > } > > +static int device_provision_capable(struct dm_target *ti, struct dm_dev *dev, > + sector_t start, sector_t len, void *data) > +{ > + return !bdev_max_provision_sectors(dev->bdev); > +} > + > +static bool dm_table_supports_provision(struct dm_table *t) > +{ > + for (unsigned int i = 0; i < t->num_targets; i++) { > + struct dm_target *ti = dm_table_get_target(t, i); > + > + if (ti->provision_supported || > + (ti->type->iterate_devices && > + ti->type->iterate_devices(ti, device_provision_capable, NULL))) > + return true; > + } > + > + return false; > +} > + > static int device_not_nowait_capable(struct dm_target *ti, struct dm_dev *dev, > sector_t start, sector_t len, void *data) > { > @@ -1983,6 +2003,11 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, > if (!dm_table_supports_write_zeroes(t)) > q->limits.max_write_zeroes_sectors = 0; > > + if (dm_table_supports_provision(t)) > + blk_queue_max_provision_sectors(q, UINT_MAX >> 9); This doesn't seem correct in that it'll override whatever max_provision_sectors was set by a target (like thinp). I think you only need the if (!dm_table_supports_provision)) case: > + else > + q->limits.max_provision_sectors = 0; > + > dm_table_verify_integrity(t); > > /* > diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c > index 13d4677baafd..b08b7ae617be 100644 > --- a/drivers/md/dm-thin.c > +++ b/drivers/md/dm-thin.c I think it'll make the most sense to split out the dm-thin.c changes in a separate patch. > @@ -909,7 +909,8 @@ static void __inc_remap_and_issue_cell(void *context, > struct bio *bio; > > while ((bio = bio_list_pop(&cell->bios))) { > - if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) > + if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD || > + bio_op(bio) == REQ_OP_PROVISION) > bio_list_add(&info->defer_bios, bio); > else { > inc_all_io_entry(info->tc->pool, bio); > @@ -1013,6 +1014,15 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m) > goto out; > } > > + /* > + * For provision requests, once the prepared block has been inserted > + * into the mapping btree, return. > + */ > + if (bio && bio_op(bio) == REQ_OP_PROVISION) { > + bio_endio(bio); > + return; > + } > + > /* > * Release any bios held while the block was being provisioned. > * If we are processing a write bio that completely covers the block, > @@ -1241,7 +1251,7 @@ static int io_overlaps_block(struct pool *pool, struct bio *bio) > > static int io_overwrites_block(struct pool *pool, struct bio *bio) > { > - return (bio_data_dir(bio) == WRITE) && > + return (bio_data_dir(bio) == WRITE) && bio_op(bio) != REQ_OP_PROVISION && > io_overlaps_block(pool, bio); > } > > @@ -1334,10 +1344,11 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, > /* > * IO to pool_dev remaps to the pool target's data_dev. > * > - * If the whole block of data is being overwritten, we can issue the > - * bio immediately. Otherwise we use kcopyd to clone the data first. > + * If the whole block of data is being overwritten and if this is not a > + * provision request, we can issue the bio immediately. > + * Otherwise we use kcopyd to clone the data first. > */ > - if (io_overwrites_block(pool, bio)) > + if (io_overwrites_block(pool, bio) && bio_op(bio) != REQ_OP_PROVISION) > remap_and_issue_overwrite(tc, bio, data_dest, m); > else { > struct dm_io_region from, to; > @@ -1356,7 +1367,8 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, > /* > * Do we need to zero a tail region? > */ > - if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) { > + if (len < pool->sectors_per_block && pool->pf.zero_new_blocks && > + bio_op(bio) != REQ_OP_PROVISION) { > atomic_inc(&m->prepare_actions); > ll_zero(tc, m, > data_dest * pool->sectors_per_block + len, > @@ -1390,6 +1402,10 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, > m->data_block = data_block; > m->cell = cell; > > + /* Provision requests are chained on the original bio. */ > + if (bio && bio_op(bio) == REQ_OP_PROVISION) > + m->bio = bio; > + > /* > * If the whole block of data is being overwritten or we are not > * zeroing pre-existing data, we can issue the bio immediately. > @@ -1865,7 +1881,8 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio, > > if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) { > break_sharing(tc, bio, block, &key, lookup_result, data_cell); > - cell_defer_no_holder(tc, virt_cell); > + if (bio_op(bio) != REQ_OP_PROVISION) > + cell_defer_no_holder(tc, virt_cell); > } else { > struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); > Not confident in the above changes given the request that we only handle REQ_OP_PROVISION one thinp block at a time. So I'll gloss over them for now. > @@ -1982,6 +1999,73 @@ static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) > } > } > > +static void process_provision_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) > +{ > + int r; > + struct pool *pool = tc->pool; > + struct bio *bio = cell->holder; > + dm_block_t begin, end; > + struct dm_thin_lookup_result lookup_result; > + > + if (tc->requeue_mode) { > + cell_requeue(pool, cell); > + return; > + } > + > + get_bio_block_range(tc, bio, &begin, &end); > + > + while (begin != end) { > + r = ensure_next_mapping(pool); > + if (r) > + /* we did our best */ > + return; > + > + r = dm_thin_find_block(tc->td, begin, 1, &lookup_result); > + switch (r) { > + case 0: > + if (lookup_result.shared) > + process_shared_bio(tc, bio, begin, > + &lookup_result, cell); > + begin++; > + break; > + case -ENODATA: > + bio_inc_remaining(bio); > + provision_block(tc, bio, begin, cell); > + begin++; > + break; > + default: > + DMERR_LIMIT( > + "%s: dm_thin_find_block() failed: error = %d", > + __func__, r); > + cell_defer_no_holder(tc, cell); > + bio_io_error(bio); > + begin++; > + break; > + } > + } > + bio_endio(bio); > + cell_defer_no_holder(tc, cell); > +} > + > +static void process_provision_bio(struct thin_c *tc, struct bio *bio) > +{ > + dm_block_t begin, end; > + struct dm_cell_key virt_key; > + struct dm_bio_prison_cell *virt_cell; > + > + get_bio_block_range(tc, bio, &begin, &end); > + if (begin == end) { > + bio_endio(bio); > + return; > + } Like Joe mentioned, this pattern was fine for discards because they are advisory/optional. But we need to make sure we don't truncate REQ_OP_PROVISION -- so we need to round up if we partially bleed into the blocks to the left or right. BUT ranged REQ_OP_PROVISION support is for later, this can be dealt with more simply in that each REQ_OP_PROVISION will be handled a block at a time initially. SO you'll want to honor _all_ REQ_OP_PROVISION, never returning early. > + > + build_key(tc->td, VIRTUAL, begin, end, &virt_key); > + if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) > + return; > + > + process_provision_cell(tc, virt_cell); > +} > + > static void process_bio(struct thin_c *tc, struct bio *bio) > { > struct pool *pool = tc->pool; > @@ -2202,6 +2286,8 @@ static void process_thin_deferred_bios(struct thin_c *tc) > > if (bio_op(bio) == REQ_OP_DISCARD) > pool->process_discard(tc, bio); > + else if (bio_op(bio) == REQ_OP_PROVISION) > + process_provision_bio(tc, bio); This should be pool->process_provision() (or ->process_provision_bio if you like). Point is, you need to be switching these methods if/when the pool_mode transitions in set_pool_mode(). > else > pool->process_bio(tc, bio); > > @@ -2723,7 +2809,8 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio) > return DM_MAPIO_SUBMITTED; > } > > - if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) { > + if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD || > + bio_op(bio) == REQ_OP_PROVISION) { > thin_defer_bio_with_throttle(tc, bio); > return DM_MAPIO_SUBMITTED; > } > @@ -3370,6 +3457,8 @@ static int pool_ctr(struct dm_target *ti, unsigned int argc, char **argv) > pt->adjusted_pf = pt->requested_pf = pf; > ti->num_flush_bios = 1; > ti->limit_swap_bios = true; > + ti->num_provision_bios = 1; > + ti->provision_supported = true; > > /* > * Only need to enable discards if the pool should pass > @@ -4068,6 +4157,7 @@ static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) > blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); > } > > + Please fix this extra whitespace damage. > /* > * pt->adjusted_pf is a staging area for the actual features to use. > * They get transferred to the live pool in bind_control_target() > @@ -4261,6 +4351,9 @@ static int thin_ctr(struct dm_target *ti, unsigned int argc, char **argv) > ti->num_discard_bios = 1; > } > > + ti->num_provision_bios = 1; > + ti->provision_supported = true; > + > mutex_unlock(&dm_thin_pool_table.mutex); > > spin_lock_irq(&tc->pool->lock); > @@ -4475,6 +4568,7 @@ static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) > > limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; > limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */ > + limits->max_provision_sectors = 2048 * 1024 * 16; /* 16G */ Building on my previous reply, with suggested update to dm.c:__process_abnormal_io(), once you rebase on dm-6.4's dm-thin.c you'll want to instead: limits->max_provision_sectors = pool->sectors_per_block << SECTOR_SHIFT; And you'll want to drop any of the above code that deals with handling bio-prison range locking and processing of REQ_OP_PROVISION for multiple thinp blocks at once. Simple REQ_OP_PROVISION processing one thinp block at a time first and then we can worry about handling REQ_OP_PROVISION that span blocks later. > static struct target_type thin_target = { > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > index dfde0088147a..d8f1803062b7 100644 > --- a/drivers/md/dm.c > +++ b/drivers/md/dm.c > @@ -1593,6 +1593,7 @@ static bool is_abnormal_io(struct bio *bio) > case REQ_OP_DISCARD: > case REQ_OP_SECURE_ERASE: > case REQ_OP_WRITE_ZEROES: > + case REQ_OP_PROVISION: > return true; > default: > break; > @@ -1617,6 +1618,9 @@ static blk_status_t __process_abnormal_io(struct clone_info *ci, > case REQ_OP_WRITE_ZEROES: > num_bios = ti->num_write_zeroes_bios; > break; > + case REQ_OP_PROVISION: > + num_bios = ti->num_provision_bios; > + break; > default: > break; > } Please be sure to include my suggested __process_abnormal_io change from my previous reply. > diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h > index 7975483816e4..e9f687521ae6 100644 > --- a/include/linux/device-mapper.h > +++ b/include/linux/device-mapper.h > @@ -334,6 +334,12 @@ struct dm_target { > */ > unsigned int num_write_zeroes_bios; > > + /* > + * The number of PROVISION bios that will be submitted to the target. > + * The bio number can be accessed with dm_bio_get_target_bio_nr. > + */ > + unsigned int num_provision_bios; > + > /* > * The minimum number of extra bytes allocated in each io for the > * target to use. > @@ -358,6 +364,11 @@ struct dm_target { > */ > bool discards_supported:1; > > + /* Set if this target needs to receive provision requests regardless of > + * whether or not its underlying devices have support. > + */ > + bool provision_supported:1; > + > /* > * Set if we need to limit the number of in-flight bios when swapping. > */ You'll need to add max_provision_granularity bool too (as implied by the dm.c:__process_abnormal_io() change suggested in my first reply to this patch). I'm happy to wait for you to consume the v3 feedback we've provided so you can create a v4. I'm thinking I can base dm-thin.c's WRITE_ZEROES support ontop of your REQ_OP_PROVISION v4 changes -- they should be complementary. Thanks, Mike
On Fri, Apr 14, 2023 at 2:58 PM Mike Snitzer <snitzer@kernel.org> wrote: > > On Thu, Apr 13 2023 at 8:02P -0400, > Sarthak Kukreti <sarthakkukreti@chromium.org> wrote: > > > Add support to dm devices for REQ_OP_PROVISION. The default mode > > is to passthrough the request to the underlying device, if it > > supports it. dm-thinpool uses the provision request to provision > > blocks for a dm-thin device. dm-thinpool currently does not > > pass through REQ_OP_PROVISION to underlying devices. > > > > For shared blocks, provision requests will break sharing and copy the > > contents of the entire block. > > > > Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org> > > --- > > drivers/md/dm-crypt.c | 4 +- > > drivers/md/dm-linear.c | 1 + > > drivers/md/dm-snap.c | 7 +++ > > Have you tested REQ_OP_PROVISION with these targets? Just want to > make sure you have an explicit need (and vested interest) for them > passing through REQ_OP_PROVISION. > Yes. I have a vested interest in dm-linear and dm-crypt; I kept dm-snap support mostly for consistency with thin snapshots. > > diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c > > index 2055a758541d..5985343384a7 100644 > > --- a/drivers/md/dm-table.c > > +++ b/drivers/md/dm-table.c > > @@ -1850,6 +1850,26 @@ static bool dm_table_supports_write_zeroes(struct dm_table *t) > > return true; > > } > > > > +static int device_provision_capable(struct dm_target *ti, struct dm_dev *dev, > > + sector_t start, sector_t len, void *data) > > +{ > > + return !bdev_max_provision_sectors(dev->bdev); > > +} > > + > > +static bool dm_table_supports_provision(struct dm_table *t) > > +{ > > + for (unsigned int i = 0; i < t->num_targets; i++) { > > + struct dm_target *ti = dm_table_get_target(t, i); > > + > > + if (ti->provision_supported || > > + (ti->type->iterate_devices && > > + ti->type->iterate_devices(ti, device_provision_capable, NULL))) > > + return true; > > + } > > + > > + return false; > > +} > > + > > static int device_not_nowait_capable(struct dm_target *ti, struct dm_dev *dev, > > sector_t start, sector_t len, void *data) > > { > > @@ -1983,6 +2003,11 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, > > if (!dm_table_supports_write_zeroes(t)) > > q->limits.max_write_zeroes_sectors = 0; > > > > + if (dm_table_supports_provision(t)) > > + blk_queue_max_provision_sectors(q, UINT_MAX >> 9); > > This doesn't seem correct in that it'll override whatever > max_provision_sectors was set by a target (like thinp). > > I think you only need the if (!dm_table_supports_provision)) case: > Done > > + else > > + q->limits.max_provision_sectors = 0; > > + > > dm_table_verify_integrity(t); > > > > /* > > diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c > > index 13d4677baafd..b08b7ae617be 100644 > > --- a/drivers/md/dm-thin.c > > +++ b/drivers/md/dm-thin.c > > I think it'll make the most sense to split out the dm-thin.c changes > in a separate patch. > Separated the dm-thin changes into a separate patch that follows this one in v4. > > @@ -909,7 +909,8 @@ static void __inc_remap_and_issue_cell(void *context, > > struct bio *bio; > > > > while ((bio = bio_list_pop(&cell->bios))) { > > - if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) > > + if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD || > > + bio_op(bio) == REQ_OP_PROVISION) > > bio_list_add(&info->defer_bios, bio); > > else { > > inc_all_io_entry(info->tc->pool, bio); > > @@ -1013,6 +1014,15 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m) > > goto out; > > } > > > > + /* > > + * For provision requests, once the prepared block has been inserted > > + * into the mapping btree, return. > > + */ > > + if (bio && bio_op(bio) == REQ_OP_PROVISION) { > > + bio_endio(bio); > > + return; > > + } > > + > > /* > > * Release any bios held while the block was being provisioned. > > * If we are processing a write bio that completely covers the block, > > @@ -1241,7 +1251,7 @@ static int io_overlaps_block(struct pool *pool, struct bio *bio) > > > > static int io_overwrites_block(struct pool *pool, struct bio *bio) > > { > > - return (bio_data_dir(bio) == WRITE) && > > + return (bio_data_dir(bio) == WRITE) && bio_op(bio) != REQ_OP_PROVISION && > > io_overlaps_block(pool, bio); > > } > > > > @@ -1334,10 +1344,11 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, > > /* > > * IO to pool_dev remaps to the pool target's data_dev. > > * > > - * If the whole block of data is being overwritten, we can issue the > > - * bio immediately. Otherwise we use kcopyd to clone the data first. > > + * If the whole block of data is being overwritten and if this is not a > > + * provision request, we can issue the bio immediately. > > + * Otherwise we use kcopyd to clone the data first. > > */ > > - if (io_overwrites_block(pool, bio)) > > + if (io_overwrites_block(pool, bio) && bio_op(bio) != REQ_OP_PROVISION) > > remap_and_issue_overwrite(tc, bio, data_dest, m); > > else { > > struct dm_io_region from, to; > > @@ -1356,7 +1367,8 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, > > /* > > * Do we need to zero a tail region? > > */ > > - if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) { > > + if (len < pool->sectors_per_block && pool->pf.zero_new_blocks && > > + bio_op(bio) != REQ_OP_PROVISION) { > > atomic_inc(&m->prepare_actions); > > ll_zero(tc, m, > > data_dest * pool->sectors_per_block + len, > > @@ -1390,6 +1402,10 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, > > m->data_block = data_block; > > m->cell = cell; > > > > + /* Provision requests are chained on the original bio. */ > > + if (bio && bio_op(bio) == REQ_OP_PROVISION) > > + m->bio = bio; > > + > > /* > > * If the whole block of data is being overwritten or we are not > > * zeroing pre-existing data, we can issue the bio immediately. > > @@ -1865,7 +1881,8 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio, > > > > if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) { > > break_sharing(tc, bio, block, &key, lookup_result, data_cell); > > - cell_defer_no_holder(tc, virt_cell); > > + if (bio_op(bio) != REQ_OP_PROVISION) > > + cell_defer_no_holder(tc, virt_cell); > > } else { > > struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); > > > > Not confident in the above changes given the request that we only > handle REQ_OP_PROVISION one thinp block at a time. So I'll gloss over > them for now. > Yeah, the majority of this got removed in v4. I added a check in io_overwrites_block() to return false for all provision requests. > > @@ -1982,6 +1999,73 @@ static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) > > } > > } > > > > +static void process_provision_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) > > +{ > > + int r; > > + struct pool *pool = tc->pool; > > + struct bio *bio = cell->holder; > > + dm_block_t begin, end; > > + struct dm_thin_lookup_result lookup_result; > > + > > + if (tc->requeue_mode) { > > + cell_requeue(pool, cell); > > + return; > > + } > > + > > + get_bio_block_range(tc, bio, &begin, &end); > > + > > + while (begin != end) { > > + r = ensure_next_mapping(pool); > > + if (r) > > + /* we did our best */ > > + return; > > + > > + r = dm_thin_find_block(tc->td, begin, 1, &lookup_result); > > + switch (r) { > > + case 0: > > + if (lookup_result.shared) > > + process_shared_bio(tc, bio, begin, > > + &lookup_result, cell); > > + begin++; > > + break; > > + case -ENODATA: > > + bio_inc_remaining(bio); > > + provision_block(tc, bio, begin, cell); > > + begin++; > > + break; > > + default: > > + DMERR_LIMIT( > > + "%s: dm_thin_find_block() failed: error = %d", > > + __func__, r); > > + cell_defer_no_holder(tc, cell); > > + bio_io_error(bio); > > + begin++; > > + break; > > + } > > + } > > + bio_endio(bio); > > + cell_defer_no_holder(tc, cell); > > +} > > + > > +static void process_provision_bio(struct thin_c *tc, struct bio *bio) > > +{ > > + dm_block_t begin, end; > > + struct dm_cell_key virt_key; > > + struct dm_bio_prison_cell *virt_cell; > > + > > + get_bio_block_range(tc, bio, &begin, &end); > > + if (begin == end) { > > + bio_endio(bio); > > + return; > > + } > > Like Joe mentioned, this pattern was fine for discards because they > are advisory/optional. But we need to make sure we don't truncate > REQ_OP_PROVISION -- so we need to round up if we partially bleed into > the blocks to the left or right. > > BUT ranged REQ_OP_PROVISION support is for later, this can be dealt > with more simply in that each REQ_OP_PROVISION will be handled a block > at a time initially. SO you'll want to honor _all_ REQ_OP_PROVISION, > never returning early. > Thanks. The next patch in the series has the simplified version. It had a lot in common with process_bio() so there was a possibility for merging the two code paths, but I opted to keep it like this to make ranged handling and passdown support easier to implement. > > + > > + build_key(tc->td, VIRTUAL, begin, end, &virt_key); > > + if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) > > + return; > > + > > + process_provision_cell(tc, virt_cell); > > +} > > + > > static void process_bio(struct thin_c *tc, struct bio *bio) > > { > > struct pool *pool = tc->pool; > > @@ -2202,6 +2286,8 @@ static void process_thin_deferred_bios(struct thin_c *tc) > > > > if (bio_op(bio) == REQ_OP_DISCARD) > > pool->process_discard(tc, bio); > > + else if (bio_op(bio) == REQ_OP_PROVISION) > > + process_provision_bio(tc, bio); > > This should be pool->process_provision() (or ->process_provision_bio > if you like). Point is, you need to be switching these methods > if/when the pool_mode transitions in set_pool_mode(). > Done > > else > > pool->process_bio(tc, bio); > > > > @@ -2723,7 +2809,8 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio) > > return DM_MAPIO_SUBMITTED; > > } > > > > - if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) { > > + if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD || > > + bio_op(bio) == REQ_OP_PROVISION) { > > thin_defer_bio_with_throttle(tc, bio); > > return DM_MAPIO_SUBMITTED; > > } > > @@ -3370,6 +3457,8 @@ static int pool_ctr(struct dm_target *ti, unsigned int argc, char **argv) > > pt->adjusted_pf = pt->requested_pf = pf; > > ti->num_flush_bios = 1; > > ti->limit_swap_bios = true; > > + ti->num_provision_bios = 1; > > + ti->provision_supported = true; > > > > /* > > * Only need to enable discards if the pool should pass > > @@ -4068,6 +4157,7 @@ static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) > > blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); > > } > > > > + > > Please fix this extra whitespace damage. > Done > > /* > > * pt->adjusted_pf is a staging area for the actual features to use. > > * They get transferred to the live pool in bind_control_target() > > @@ -4261,6 +4351,9 @@ static int thin_ctr(struct dm_target *ti, unsigned int argc, char **argv) > > ti->num_discard_bios = 1; > > } > > > > + ti->num_provision_bios = 1; > > + ti->provision_supported = true; > > + > > mutex_unlock(&dm_thin_pool_table.mutex); > > > > spin_lock_irq(&tc->pool->lock); > > @@ -4475,6 +4568,7 @@ static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) > > > > limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; > > limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */ > > + limits->max_provision_sectors = 2048 * 1024 * 16; /* 16G */ > > Building on my previous reply, with suggested update to > dm.c:__process_abnormal_io(), once you rebase on dm-6.4's dm-thin.c > you'll want to instead: > > limits->max_provision_sectors = pool->sectors_per_block << SECTOR_SHIFT; > > And you'll want to drop any of the above code that deals with handling > bio-prison range locking and processing of REQ_OP_PROVISION for > multiple thinp blocks at once. > > Simple REQ_OP_PROVISION processing one thinp block at a time first and > then we can worry about handling REQ_OP_PROVISION that span blocks > later. > Thanks, done in v4. > > static struct target_type thin_target = { > > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > > index dfde0088147a..d8f1803062b7 100644 > > --- a/drivers/md/dm.c > > +++ b/drivers/md/dm.c > > @@ -1593,6 +1593,7 @@ static bool is_abnormal_io(struct bio *bio) > > case REQ_OP_DISCARD: > > case REQ_OP_SECURE_ERASE: > > case REQ_OP_WRITE_ZEROES: > > + case REQ_OP_PROVISION: > > return true; > > default: > > break; > > @@ -1617,6 +1618,9 @@ static blk_status_t __process_abnormal_io(struct clone_info *ci, > > case REQ_OP_WRITE_ZEROES: > > num_bios = ti->num_write_zeroes_bios; > > break; > > + case REQ_OP_PROVISION: > > + num_bios = ti->num_provision_bios; > > + break; > > default: > > break; > > } > > Please be sure to include my suggested __process_abnormal_io change > from my previous reply. > Done. > > diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h > > index 7975483816e4..e9f687521ae6 100644 > > --- a/include/linux/device-mapper.h > > +++ b/include/linux/device-mapper.h > > @@ -334,6 +334,12 @@ struct dm_target { > > */ > > unsigned int num_write_zeroes_bios; > > > > + /* > > + * The number of PROVISION bios that will be submitted to the target. > > + * The bio number can be accessed with dm_bio_get_target_bio_nr. > > + */ > > + unsigned int num_provision_bios; > > + > > /* > > * The minimum number of extra bytes allocated in each io for the > > * target to use. > > @@ -358,6 +364,11 @@ struct dm_target { > > */ > > bool discards_supported:1; > > > > + /* Set if this target needs to receive provision requests regardless of > > + * whether or not its underlying devices have support. > > + */ > > + bool provision_supported:1; > > + > > /* > > * Set if we need to limit the number of in-flight bios when swapping. > > */ > > You'll need to add max_provision_granularity bool too (as implied by > the dm.c:__process_abnormal_io() change suggested in my first reply to > this patch). > > I'm happy to wait for you to consume the v3 feedback we've provided so > you can create a v4. I'm thinking I can base dm-thin.c's WRITE_ZEROES > support ontop of your REQ_OP_PROVISION v4 changes -- they should be > complementary. > Done. Thanks for the review and guidance! Best Sarthak > Thanks, > Mike
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index 3ba53dc3cc3f..5c655bfd4686 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -3087,6 +3087,8 @@ static int crypt_ctr_optional(struct dm_target *ti, unsigned int argc, char **ar if (ret) return ret; + ti->num_provision_bios = 1; + while (opt_params--) { opt_string = dm_shift_arg(&as); if (!opt_string) { @@ -3390,7 +3392,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio) * - for REQ_OP_DISCARD caller must use flush if IO ordering matters */ if (unlikely(bio->bi_opf & REQ_PREFLUSH || - bio_op(bio) == REQ_OP_DISCARD)) { + bio_op(bio) == REQ_OP_DISCARD || bio_op(bio) == REQ_OP_PROVISION)) { bio_set_dev(bio, cc->dev->bdev); if (bio_sectors(bio)) bio->bi_iter.bi_sector = cc->start + diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c index 3e622dcc9dbd..7843e548e850 100644 --- a/drivers/md/dm-linear.c +++ b/drivers/md/dm-linear.c @@ -62,6 +62,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) ti->num_discard_bios = 1; ti->num_secure_erase_bios = 1; ti->num_write_zeroes_bios = 1; + ti->num_provision_bios = 1; ti->private = lc; return 0; diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index f766c21408f1..f6b224a12000 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -1358,6 +1358,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) if (s->discard_zeroes_cow) ti->num_discard_bios = (s->discard_passdown_origin ? 2 : 1); ti->per_io_data_size = sizeof(struct dm_snap_tracked_chunk); + ti->num_provision_bios = 1; /* Add snapshot to the list of snapshots for this origin */ /* Exceptions aren't triggered till snapshot_resume() is called */ @@ -2003,6 +2004,11 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio) /* If the block is already remapped - use that, else remap it */ e = dm_lookup_exception(&s->complete, chunk); if (e) { + if (unlikely(bio_op(bio) == REQ_OP_PROVISION)) { + bio_endio(bio); + r = DM_MAPIO_SUBMITTED; + goto out_unlock; + } remap_exception(s, e, bio, chunk); if (unlikely(bio_op(bio) == REQ_OP_DISCARD) && io_overlaps_chunk(s, bio)) { @@ -2413,6 +2419,7 @@ static void snapshot_io_hints(struct dm_target *ti, struct queue_limits *limits) /* All discards are split on chunk_size boundary */ limits->discard_granularity = snap->store->chunk_size; limits->max_discard_sectors = snap->store->chunk_size; + limits->max_provision_sectors = snap->store->chunk_size; up_read(&_origins_lock); } diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 2055a758541d..5985343384a7 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1850,6 +1850,26 @@ static bool dm_table_supports_write_zeroes(struct dm_table *t) return true; } +static int device_provision_capable(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *data) +{ + return !bdev_max_provision_sectors(dev->bdev); +} + +static bool dm_table_supports_provision(struct dm_table *t) +{ + for (unsigned int i = 0; i < t->num_targets; i++) { + struct dm_target *ti = dm_table_get_target(t, i); + + if (ti->provision_supported || + (ti->type->iterate_devices && + ti->type->iterate_devices(ti, device_provision_capable, NULL))) + return true; + } + + return false; +} + static int device_not_nowait_capable(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { @@ -1983,6 +2003,11 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, if (!dm_table_supports_write_zeroes(t)) q->limits.max_write_zeroes_sectors = 0; + if (dm_table_supports_provision(t)) + blk_queue_max_provision_sectors(q, UINT_MAX >> 9); + else + q->limits.max_provision_sectors = 0; + dm_table_verify_integrity(t); /* diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 13d4677baafd..b08b7ae617be 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -909,7 +909,8 @@ static void __inc_remap_and_issue_cell(void *context, struct bio *bio; while ((bio = bio_list_pop(&cell->bios))) { - if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) + if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD || + bio_op(bio) == REQ_OP_PROVISION) bio_list_add(&info->defer_bios, bio); else { inc_all_io_entry(info->tc->pool, bio); @@ -1013,6 +1014,15 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m) goto out; } + /* + * For provision requests, once the prepared block has been inserted + * into the mapping btree, return. + */ + if (bio && bio_op(bio) == REQ_OP_PROVISION) { + bio_endio(bio); + return; + } + /* * Release any bios held while the block was being provisioned. * If we are processing a write bio that completely covers the block, @@ -1241,7 +1251,7 @@ static int io_overlaps_block(struct pool *pool, struct bio *bio) static int io_overwrites_block(struct pool *pool, struct bio *bio) { - return (bio_data_dir(bio) == WRITE) && + return (bio_data_dir(bio) == WRITE) && bio_op(bio) != REQ_OP_PROVISION && io_overlaps_block(pool, bio); } @@ -1334,10 +1344,11 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, /* * IO to pool_dev remaps to the pool target's data_dev. * - * If the whole block of data is being overwritten, we can issue the - * bio immediately. Otherwise we use kcopyd to clone the data first. + * If the whole block of data is being overwritten and if this is not a + * provision request, we can issue the bio immediately. + * Otherwise we use kcopyd to clone the data first. */ - if (io_overwrites_block(pool, bio)) + if (io_overwrites_block(pool, bio) && bio_op(bio) != REQ_OP_PROVISION) remap_and_issue_overwrite(tc, bio, data_dest, m); else { struct dm_io_region from, to; @@ -1356,7 +1367,8 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, /* * Do we need to zero a tail region? */ - if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) { + if (len < pool->sectors_per_block && pool->pf.zero_new_blocks && + bio_op(bio) != REQ_OP_PROVISION) { atomic_inc(&m->prepare_actions); ll_zero(tc, m, data_dest * pool->sectors_per_block + len, @@ -1390,6 +1402,10 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, m->data_block = data_block; m->cell = cell; + /* Provision requests are chained on the original bio. */ + if (bio && bio_op(bio) == REQ_OP_PROVISION) + m->bio = bio; + /* * If the whole block of data is being overwritten or we are not * zeroing pre-existing data, we can issue the bio immediately. @@ -1865,7 +1881,8 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio, if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) { break_sharing(tc, bio, block, &key, lookup_result, data_cell); - cell_defer_no_holder(tc, virt_cell); + if (bio_op(bio) != REQ_OP_PROVISION) + cell_defer_no_holder(tc, virt_cell); } else { struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); @@ -1982,6 +1999,73 @@ static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) } } +static void process_provision_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) +{ + int r; + struct pool *pool = tc->pool; + struct bio *bio = cell->holder; + dm_block_t begin, end; + struct dm_thin_lookup_result lookup_result; + + if (tc->requeue_mode) { + cell_requeue(pool, cell); + return; + } + + get_bio_block_range(tc, bio, &begin, &end); + + while (begin != end) { + r = ensure_next_mapping(pool); + if (r) + /* we did our best */ + return; + + r = dm_thin_find_block(tc->td, begin, 1, &lookup_result); + switch (r) { + case 0: + if (lookup_result.shared) + process_shared_bio(tc, bio, begin, + &lookup_result, cell); + begin++; + break; + case -ENODATA: + bio_inc_remaining(bio); + provision_block(tc, bio, begin, cell); + begin++; + break; + default: + DMERR_LIMIT( + "%s: dm_thin_find_block() failed: error = %d", + __func__, r); + cell_defer_no_holder(tc, cell); + bio_io_error(bio); + begin++; + break; + } + } + bio_endio(bio); + cell_defer_no_holder(tc, cell); +} + +static void process_provision_bio(struct thin_c *tc, struct bio *bio) +{ + dm_block_t begin, end; + struct dm_cell_key virt_key; + struct dm_bio_prison_cell *virt_cell; + + get_bio_block_range(tc, bio, &begin, &end); + if (begin == end) { + bio_endio(bio); + return; + } + + build_key(tc->td, VIRTUAL, begin, end, &virt_key); + if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) + return; + + process_provision_cell(tc, virt_cell); +} + static void process_bio(struct thin_c *tc, struct bio *bio) { struct pool *pool = tc->pool; @@ -2202,6 +2286,8 @@ static void process_thin_deferred_bios(struct thin_c *tc) if (bio_op(bio) == REQ_OP_DISCARD) pool->process_discard(tc, bio); + else if (bio_op(bio) == REQ_OP_PROVISION) + process_provision_bio(tc, bio); else pool->process_bio(tc, bio); @@ -2723,7 +2809,8 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio) return DM_MAPIO_SUBMITTED; } - if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) { + if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD || + bio_op(bio) == REQ_OP_PROVISION) { thin_defer_bio_with_throttle(tc, bio); return DM_MAPIO_SUBMITTED; } @@ -3370,6 +3457,8 @@ static int pool_ctr(struct dm_target *ti, unsigned int argc, char **argv) pt->adjusted_pf = pt->requested_pf = pf; ti->num_flush_bios = 1; ti->limit_swap_bios = true; + ti->num_provision_bios = 1; + ti->provision_supported = true; /* * Only need to enable discards if the pool should pass @@ -4068,6 +4157,7 @@ static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); } + /* * pt->adjusted_pf is a staging area for the actual features to use. * They get transferred to the live pool in bind_control_target() @@ -4261,6 +4351,9 @@ static int thin_ctr(struct dm_target *ti, unsigned int argc, char **argv) ti->num_discard_bios = 1; } + ti->num_provision_bios = 1; + ti->provision_supported = true; + mutex_unlock(&dm_thin_pool_table.mutex); spin_lock_irq(&tc->pool->lock); @@ -4475,6 +4568,7 @@ static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */ + limits->max_provision_sectors = 2048 * 1024 * 16; /* 16G */ } static struct target_type thin_target = { diff --git a/drivers/md/dm.c b/drivers/md/dm.c index dfde0088147a..d8f1803062b7 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1593,6 +1593,7 @@ static bool is_abnormal_io(struct bio *bio) case REQ_OP_DISCARD: case REQ_OP_SECURE_ERASE: case REQ_OP_WRITE_ZEROES: + case REQ_OP_PROVISION: return true; default: break; @@ -1617,6 +1618,9 @@ static blk_status_t __process_abnormal_io(struct clone_info *ci, case REQ_OP_WRITE_ZEROES: num_bios = ti->num_write_zeroes_bios; break; + case REQ_OP_PROVISION: + num_bios = ti->num_provision_bios; + break; default: break; } diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 7975483816e4..e9f687521ae6 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -334,6 +334,12 @@ struct dm_target { */ unsigned int num_write_zeroes_bios; + /* + * The number of PROVISION bios that will be submitted to the target. + * The bio number can be accessed with dm_bio_get_target_bio_nr. + */ + unsigned int num_provision_bios; + /* * The minimum number of extra bytes allocated in each io for the * target to use. @@ -358,6 +364,11 @@ struct dm_target { */ bool discards_supported:1; + /* Set if this target needs to receive provision requests regardless of + * whether or not its underlying devices have support. + */ + bool provision_supported:1; + /* * Set if we need to limit the number of in-flight bios when swapping. */
Add support to dm devices for REQ_OP_PROVISION. The default mode is to passthrough the request to the underlying device, if it supports it. dm-thinpool uses the provision request to provision blocks for a dm-thin device. dm-thinpool currently does not pass through REQ_OP_PROVISION to underlying devices. For shared blocks, provision requests will break sharing and copy the contents of the entire block. Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org> --- drivers/md/dm-crypt.c | 4 +- drivers/md/dm-linear.c | 1 + drivers/md/dm-snap.c | 7 +++ drivers/md/dm-table.c | 25 ++++++++ drivers/md/dm-thin.c | 110 +++++++++++++++++++++++++++++++--- drivers/md/dm.c | 4 ++ include/linux/device-mapper.h | 11 ++++ 7 files changed, 153 insertions(+), 9 deletions(-)