| Message ID | 20230414000219.92640-1-sarthakkukreti@chromium.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | Introduce provisioning primitives for thinly provisioned storage | expand |
Next revision of adding support for block provisioning requests. Changes from v4: - Add fix for block devices invalidating pagecache if blkdev_fallocate() is called with an invalid mode. - s/max_provision_sectors/provision_max_bytes in sysfs. Sarthak Kukreti (5): block: Don't invalidate pagecache for invalid falloc modes block: Introduce provisioning primitives dm: Add block provisioning support dm-thin: Add REQ_OP_PROVISION support loop: Add support for provision requests block/blk-core.c | 5 +++ block/blk-lib.c | 53 +++++++++++++++++++++++++ block/blk-merge.c | 18 +++++++++ block/blk-settings.c | 19 +++++++++ block/blk-sysfs.c | 9 +++++ block/bounce.c | 1 + block/fops.c | 28 +++++++++----- drivers/block/loop.c | 42 ++++++++++++++++++++ drivers/md/dm-crypt.c | 5 ++- drivers/md/dm-linear.c | 2 + drivers/md/dm-snap.c | 8 ++++ drivers/md/dm-table.c | 23 +++++++++++ drivers/md/dm-thin.c | 73 ++++++++++++++++++++++++++++++++--- drivers/md/dm.c | 6 +++ include/linux/bio.h | 6 ++- include/linux/blk_types.h | 5 ++- include/linux/blkdev.h | 16 ++++++++ include/linux/device-mapper.h | 17 ++++++++ 18 files changed, 318 insertions(+), 18 deletions(-)
Hi, This patch series covers iteration 6 of adding support for block provisioning requests. Changes from v5: - Remove explicit supports_provision from dm devices. - Move provision sectors io hint to pool_io_hint. Other devices will derive the provisioning limits from the stack. - Remove artifact from v4 to omit cell_defer_no_holder for REQ_OP_PROVISION. - Fix blkdev_fallocate() called with invalid fallocate modes to propagate errors correctly. Sarthak Kukreti (5): block: Don't invalidate pagecache for invalid falloc modes block: Introduce provisioning primitives dm: Add block provisioning support dm-thin: Add REQ_OP_PROVISION support loop: Add support for provision requests block/blk-core.c | 5 +++ block/blk-lib.c | 53 ++++++++++++++++++++++++++ block/blk-merge.c | 18 +++++++++ block/blk-settings.c | 19 ++++++++++ block/blk-sysfs.c | 9 +++++ block/bounce.c | 1 + block/fops.c | 31 +++++++++++++--- drivers/block/loop.c | 42 +++++++++++++++++++++ drivers/md/dm-crypt.c | 4 +- drivers/md/dm-linear.c | 1 + drivers/md/dm-snap.c | 7 ++++ drivers/md/dm-table.c | 23 ++++++++++++ drivers/md/dm-thin.c | 70 +++++++++++++++++++++++++++++++++-- drivers/md/dm.c | 6 +++ include/linux/bio.h | 6 ++- include/linux/blk_types.h | 5 ++- include/linux/blkdev.h | 16 ++++++++ include/linux/device-mapper.h | 17 +++++++++ 18 files changed, 319 insertions(+), 14 deletions(-)
On Fri, May 05, 2023 at 11:29:04PM -0700, Sarthak Kukreti wrote: > Hi, > > This patch series covers iteration 6 of adding support for block > provisioning requests. I didn't even notice there was a v6. Could you start a fresh thread when you bump the revision count, please? --D > Changes from v5: > - Remove explicit supports_provision from dm devices. > - Move provision sectors io hint to pool_io_hint. Other devices > will derive the provisioning limits from the stack. > - Remove artifact from v4 to omit cell_defer_no_holder for > REQ_OP_PROVISION. > - Fix blkdev_fallocate() called with invalid fallocate > modes to propagate errors correctly. > > Sarthak Kukreti (5): > block: Don't invalidate pagecache for invalid falloc modes > block: Introduce provisioning primitives > dm: Add block provisioning support > dm-thin: Add REQ_OP_PROVISION support > loop: Add support for provision requests > > block/blk-core.c | 5 +++ > block/blk-lib.c | 53 ++++++++++++++++++++++++++ > block/blk-merge.c | 18 +++++++++ > block/blk-settings.c | 19 ++++++++++ > block/blk-sysfs.c | 9 +++++ > block/bounce.c | 1 + > block/fops.c | 31 +++++++++++++--- > drivers/block/loop.c | 42 +++++++++++++++++++++ > drivers/md/dm-crypt.c | 4 +- > drivers/md/dm-linear.c | 1 + > drivers/md/dm-snap.c | 7 ++++ > drivers/md/dm-table.c | 23 ++++++++++++ > drivers/md/dm-thin.c | 70 +++++++++++++++++++++++++++++++++-- > drivers/md/dm.c | 6 +++ > include/linux/bio.h | 6 ++- > include/linux/blk_types.h | 5 ++- > include/linux/blkdev.h | 16 ++++++++ > include/linux/device-mapper.h | 17 +++++++++ > 18 files changed, 319 insertions(+), 14 deletions(-) > > -- > 2.40.1.521.gf1e218fcd8-goog >
Hi, This patch series adds a mechanism to pass through provision requests on stacked thinly provisioned block devices. The linux kernel provides several mechanisms to set up thinly provisioned block storage abstractions (eg. dm-thin, loop devices over sparse files), either directly as block devices or backing storage for filesystems. Currently, short of writing data to either the device or filesystme, there is no way for users to pre-allocate space for use in such storage setups. Consider the following use-cases: 1) Suspend-to-disk and resume from a dm-thin device: In order to ensure that the underlying thinpool metadata is not modified during the suspend mechanism, the dm-thin device needs to be fully provisioned. 2) If a filesystem uses a loop device over a sparse file, fallocate() on the filesystem will allocate blocks for files but the underlying sparse file will remain intact. 3) Another example is virtual machine using a sparse file/dm-thin as a storage device; by default, allocations within the VM boundaries will not affect the host. 4) Several storage standards support mechanisms for thin provisioning on real hardware devices. For example: a. The NVMe spec 1.0b section 2.1.1 loosely talks about thin provisioning: "When the THINP bit in the NSFEAT field of the Identify Namespace data structure is set to ‘1’, the controller ... shall track the number of allocated blocks in the Namespace Utilization field" b. The SCSi Block Commands reference - 4 section references "Thin provisioned logical units", c. UFS 3.0 spec section 13.3.3 references "Thin provisioning". In all the above situations, currently, the only way for pre-allocating space is to issue writes (or use WRITE_ZEROES/WRITE_SAME). However, that does not scale well with larger pre-allocation sizes. This patchset introduces primitives to support block-level provisioning (note: the term 'provisioning' is used to prevent overloading the term 'allocations/pre-allocations') requests across filesystems and block devices. This allows fallocate() and file creation requests to reserve space across stacked layers of block devices and filesystems. Currently, the patchset covers a prototype on the device-mapper targets, loop device and ext4, but the same mechanism can be extended to other filesystems/block devices as well as extended for use with devices in 4 a-c. Patch 1 introduces REQ_OP_PROVISION as a new request type. The provision request acts like the inverse of a discard request; instead of notifying lower layers that the block range will no longer be used, provision acts as a request to lower layers to provision disk space for the given block range. Real hardware storage devices will currently disable the provisioing capability but for the standards listed in 4a.-c., REQ_OP_PROVISION can be overloaded for use as the provisioing primitive for future devices. Patch 2 implements REQ_OP_PROVISION handling for some of the device-mapper targets. Device-mapper targets will usually mirror the support of underlying devices. This patch also enables the use of fallocate in mode == 0 for block devices. Patch 3 wires up the loop device handling of REQ_OP_PROVISION and calls fallocate() with mode 0 on the underlying file/block device. Testing: -------- - Tested on a VM running a 6.2 kernel. - Preallocation of dm-thin devices: As expected, avoiding the need to zero out thinly-provisioned block devices to preallocate space speeds up the provisioning operation significantly: The following was tested on a dm-thin device set up on top of a dm-thinp with skip_block_zeroing=true. A) Zeroout was measured using `fallocate -z ...` B) Provision was measured using `fallocate -p ...`. Size Time A B 512M real 1.093 0.034 user 0 0 sys 0.022 0.01 1G real 2.182 0.048 user 0 0.01 sys 0.022 0 2G real 4.344 0.082 user 0 0.01 sys 0.036 0 4G real 8.679 0.153 user 0 0.01 sys 0.073 0 8G real 17.777 0.318 user 0 0.01 sys 0.144 0 Changelog: V3: - Drop FALLOC_FL_PROVISION and use mode == 0 for provision requests. - Drop fs-specific patches; will be sent out in a follow up series. - Fix missing shared block handling for thin snapshots. V2: - Fix stacked limit handling. - Enable provision request handling in dm-snapshot - Don't call truncate_bdev_range if blkdev_fallocate() is called with FALLOC_FL_PROVISION. - Clarify semantics of FALLOC_FL_PROVISION and why it needs to be a separate flag (as opposed to overloading mode == 0). Sarthak Kukreti (3): block: Introduce provisioning primitives dm: Add support for block provisioning loop: Add support for provision requests block/blk-core.c | 5 ++ block/blk-lib.c | 53 ++++++++++++++++ block/blk-merge.c | 18 ++++++ block/blk-settings.c | 19 ++++++ block/blk-sysfs.c | 8 +++ block/bounce.c | 1 + block/fops.c | 14 +++-- drivers/block/loop.c | 42 +++++++++++++ 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/bio.h | 6 +- include/linux/blk_types.h | 5 +- include/linux/blkdev.h | 16 +++++ include/linux/device-mapper.h | 11 ++++ 18 files changed, 333 insertions(+), 16 deletions(-)