user/sven/linux.git/include/uapi/linux/dm-ioctl.h, branch v5.18.18

dm: add dm_submit_bio_remap interface

2022-02-21T20:36:33Z

Where possible, switch from early bio-based IO accounting (at the time DM clones each incoming bio) to late IO accounting just before each remapped bio is issued to underlying device via submit_bio_noacct(). Allows more precise bio-based IO accounting for DM targets that use their own workqueues to perform additional processing of each bio in conjunction with their DM_MAPIO_SUBMITTED return from their map function. When a target is updated to use dm_submit_bio_remap() they must also set ti->accounts_remapped_io to true. Use xchg() in start_io_acct(), as suggested by Mikulas, to ensure each IO is only started once. The xchg race only happens if __send_duplicate_bios() sends multiple bios -- that case is reflected via tio->is_duplicate_bio. Given the niche nature of this race, it is best to avoid any xchg performance penalty for normal IO. For IO that was never submitted with dm_bio_submit_remap(), but the target completes the clone with bio_endio, accounting is started then ended and pending_io counter decremented. Reviewed-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm ima: measure data on table load

2021-08-10T17:32:40Z

DM configures a block device with various target specific attributes passed to it as a table. DM loads the table, and calls each target’s respective constructors with the attributes as input parameters. Some of these attributes are critical to ensure the device meets certain security bar. Thus, IMA should measure these attributes, to ensure they are not tampered with, during the lifetime of the device. So that the external services can have high confidence in the configuration of the block-devices on a given system. Some devices may have large tables. And a given device may change its state (table-load, suspend, resume, rename, remove, table-clear etc.) many times. Measuring these attributes each time when the device changes its state will significantly increase the size of the IMA logs. Further, once configured, these attributes are not expected to change unless a new table is loaded, or a device is removed and recreated. Therefore the clear-text of the attributes should only be measured during table load, and the hash of the active/inactive table should be measured for the remaining device state changes. Export IMA function ima_measure_critical_data() to allow measurement of DM device parameters, as well as target specific attributes, during table load. Compute the hash of the inactive table and store it for measurements during future state change. If a load is called multiple times, update the inactive table hash with the hash of the latest populated table. So that the correct inactive table hash is measured when the device transitions to different states like resume, remove, rename, etc. Signed-off-by: Tushar Sugandhi Signed-off-by: Colin Ian King # leak fix Signed-off-by: Mike Snitzer

dm ioctl: return UUID in DM_LIST_DEVICES_CMD result

2021-03-26T18:53:41Z

When LVM needs to find a device with a particular UUID it needs to ask for UUID for each device. This patch returns UUID directly in the list of devices, so that LVM doesn't have to query all the devices with an ioctl. The UUID is returned if the flag DM_UUID_FLAG is set in the parameters. Returning UUID is done in backward-compatible way. There's one unused 32-bit word value after the event number. This patch sets the bit DM_NAME_LIST_FLAG_HAS_UUID if UUID is present and DM_NAME_LIST_FLAG_DOESNT_HAVE_UUID if it isn't (if none of these bits is set, then we have an old kernel that doesn't support returning UUIDs). The UUID is stored after this word. The 'next' value is updated to point after the UUID, so that old version of libdevmapper will skip the UUID without attempting to interpret it. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm: add support for passing through inline crypto support

2021-02-11T14:45:25Z

Update the device-mapper core to support exposing the inline crypto support of the underlying device(s) through the device-mapper device. This works by creating a "passthrough keyslot manager" for the dm device, which declares support for encryption settings which all underlying devices support. When a supported setting is used, the bio cloning code handles cloning the crypto context to the bios for all the underlying devices. When an unsupported setting is used, the blk-crypto fallback is used as usual. Crypto support on each underlying device is ignored unless the corresponding dm target opts into exposing it. This is needed because for inline crypto to semantically operate on the original bio, the data must not be transformed by the dm target. Thus, targets like dm-linear can expose crypto support of the underlying device, but targets like dm-crypt can't. (dm-crypt could use inline crypto itself, though.) A DM device's table can only be changed if the "new" inline encryption capabilities are a (*not* necessarily strict) superset of the "old" inline encryption capabilities. Attempts to make changes to the table that result in some inline encryption capability becoming no longer supported will be rejected. For the sake of clarity, key eviction from underlying devices will be handled in a future patch. Co-developed-by: Eric Biggers Signed-off-by: Eric Biggers Signed-off-by: Satya Tangirala Signed-off-by: Mike Snitzer

dm: export dm_copy_name_and_uuid

2020-10-01T19:03:40Z

Allow DM targets to access the configured name and uuid. Also, bump DM ioctl version. Signed-off-by: Mike Snitzer

dm: bump version of core and various targets

2020-03-03T16:10:21Z

Changes made during the 5.6 cycle warrant bumping the version number for DM core and the targets modified by this commit. It should be noted that dm-thin, dm-crypt and dm-raid already had their target version bumped during the 5.6 merge window. Signed-off-by; Mike Snitzer

dm: introduce DM_GET_TARGET_VERSION

2019-09-16T14:18:01Z

This commit introduces a new ioctl DM_GET_TARGET_VERSION. It will load a target that is specified in the "name" entry in the parameter structure and return its version. This functionality is intended to be used by cryptsetup, so that it can query kernel capabilities before activating the device. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm: eliminate 'split_discard_bios' flag from DM target interface

2019-02-21T04:24:55Z

There is no need to have DM core split discards on behalf of a DM target now that blk_queue_split() handles splitting discards based on the queue_limits. A DM target just needs to set max_discard_sectors, discard_granularity, etc, in queue_limits. Signed-off-by: Mike Snitzer

dm: hold DM table for duration of ioctl rather than use blkdev_get

2018-04-04T16:12:38Z

Commit 519049afead ("dm: use blkdev_get rather than bdgrab when issuing pass-through ioctl") inadvertantly introduced a regression relative to users of device cgroups that issue ioctls (e.g. libvirt). Using blkdev_get() in DM's passthrough ioctl support implicitly introduced a cgroup permissions check that would fail unless care were taken to add all devices in the IO stack to the device cgroup. E.g. rather than just adding the top-level DM multipath device to the cgroup all the underlying devices would need to be allowed. Fix this, to no longer require allowing all underlying devices, by simply holding the live DM table (which includes the table's original blkdev_get() reference on the blockdevice that the ioctl will be issued to) for the duration of the ioctl. Also, bump the DM ioctl version so a user can know that their device cgroup allow workaround is no longer needed. Reported-by: Michal Privoznik Suggested-by: Mikulas Patocka Fixes: 519049afead ("dm: use blkdev_get rather than bdgrab when issuing pass-through ioctl") Cc: stable@vger.kernel.org # 4.16 Signed-off-by: Mike Snitzer

dm: allow targets to return output from messages they are sent

2018-04-03T19:04:10Z

Could be useful for a target to return stats or other information. If a target does DMEMIT() anything to @result from its .message method then it must return 1 to the caller. Signed-off-By: Mike Snitzer