linux-toradex.git/include/uapi/linux/dm-ioctl.h, branch v5.14-rc6

dm ioctl: return UUID in DM_LIST_DEVICES_CMD result

2021-03-26T18:53:41+00:00

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

2021-02-11T14:45:25+00:00

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

2020-10-01T19:03:40+00:00

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

2020-03-03T16:10:21+00:00

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

2019-09-16T14:18:01+00:00

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

2019-02-21T04:24:55+00:00

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

2018-04-04T16:12:38+00:00

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

2018-04-03T19:04:10+00:00

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

License cleanup: add SPDX license identifier to uapi header files with a license

2017-11-02T10:20:11+00:00

Many user space API headers have licensing information, which is either
incomplete, badly formatted or just a shorthand for referring to the
license under which the file is supposed to be.  This makes it hard for
compliance tools to determine the correct license.

Update these files with an SPDX license identifier.  The identifier was
chosen based on the license information in the file.

GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license
identifier with the added 'WITH Linux-syscall-note' exception, which is
the officially assigned exception identifier for the kernel syscall
exception:

   NOTE! This copyright does *not* cover user programs that use kernel
   services by normal system calls - this is merely considered normal use
   of the kernel, and does *not* fall under the heading of "derived work".

This exception makes it possible to include GPL headers into non GPL
code, without confusing license compliance tools.

Headers which have either explicit dual licensing or are just licensed
under a non GPL license are updated with the corresponding SPDX
identifier and the GPLv2 with syscall exception identifier.  The format
is:
        ((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE)

SPDX license identifiers are a legally binding shorthand, which can be
used instead of the full boiler plate text.  The update does not remove
existing license information as this has to be done on a case by case
basis and the copyright holders might have to be consulted. This will
happen in a separate step.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.  See the previous patch in this series for the
methodology of how this patch was researched.

Reviewed-by: Kate Stewart 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

dm ioctl: fix alignment of event number in the device list

2017-09-25T15:18:29+00:00

The size of struct dm_name_list is different on 32-bit and 64-bit
kernels (so "(nl + 1)" differs between 32-bit and 64-bit kernels).

This mismatch caused some harmless difference in padding when using 32-bit
or 64-bit kernel. Commit 23d70c5e52dd ("dm ioctl: report event number in
DM_LIST_DEVICES") added reporting event number in the output of
DM_LIST_DEVICES_CMD. This difference in padding makes it impossible for
userspace to determine the location of the event number (the location
would be different when running on 32-bit and 64-bit kernels).

Fix the padding by using offsetof(struct dm_name_list, name) instead of
sizeof(struct dm_name_list) to determine the location of entries.

Also, the ioctl version number is incremented to 37 so that userspace
can use the version number to determine that the event number is present
and correctly located.

In addition, a global event is now raised when a DM device is created,
removed, renamed or when table is swapped, so that the user can monitor
for device changes.

Reported-by: Eugene Syromiatnikov 
Fixes: 23d70c5e52dd ("dm ioctl: report event number in DM_LIST_DEVICES")
Cc: stable@vger.kernel.org # 4.13
Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer