dm: update relevant MODULE_AUTHOR entries to latest dm-devel mailing list

Signed-off-by: Mike Snitzer <snitzer@kernel.org>

dm: add helper macro for simple DM target module init and exit

Eliminate duplicate boilerplate code for simple modules that contain
a single DM target driver without any additional setup code.

Add a new module_dm() macro, which replaces the module_init() and
module_exit() with template functions that call dm_register_target()
and dm_unregister_target() respectively.

Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

dm: push error reporting down to dm_register_target()

Simplifies each DM target's init method by making dm_register_target()
responsible for its error reporting (on behalf of targets).

Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

dm: add missing SPDX-License-Indentifiers

'GPL-2.0-only' is used instead of 'GPL-2.0' because SPDX has
deprecated its use.

Suggested-by: John Wiele <jwiele@redhat.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

dm: use bdev_nr_sectors and bdev_nr_bytes instead of open coding them

Use the proper helpers to read the block device size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20211018101130.1838532-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dm: update target status functions to support IMA measurement

For device mapper targets to take advantage of IMA's measurement
capabilities, the status functions for the individual targets need to be
updated to handle the status_type_t case for value STATUSTYPE_IMA.

Update status functions for the following target types, to log their
respective attributes to be measured using IMA.
01. cache
02. crypt
03. integrity
04. linear
05. mirror
06. multipath
07. raid
08. snapshot
09. striped
10. verity

For rest of the targets, handle the STATUSTYPE_IMA case by setting the
measurement buffer to NULL.

For IMA to measure the data on a given system, the IMA policy on the
system needs to be updated to have the following line, and the system
needs to be restarted for the measurements to take effect.

/etc/ima/ima-policy
measure func=CRITICAL_DATA label=device-mapper template=ima-buf

The measurements will be reflected in the IMA logs, which are located at:

/sys/kernel/security/integrity/ima/ascii_runtime_measurements
/sys/kernel/security/integrity/ima/binary_runtime_measurements

These IMA logs can later be consumed by various attestation clients
running on the system, and send them to external services for attesting
the system.

The DM target data measured by IMA subsystem can alternatively
be queried from userspace by setting DM_IMA_MEASUREMENT_FLAG with
DM_TABLE_STATUS_CMD.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm dust: remove h from printk format specifier

See Documentation/core-api/printk-formats.rst.

commit cbacb5ab0aa0 ("docs: printk-formats: Stop encouraging use of unnecessary %h[xudi] and %hh[xudi]")

Standard integer promotion is already done and %hx and %hhx is useless
so do not encourage the use of %hh[xudi] or %h[xudi].

Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm dust: add interface to list all badblocks

This interface may help anyone who want to know all badblocks without
querying for each block.

[Bryan: DMEMIT message if no blocks are in the bad block list.]

Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Bryan Gurney <bgurney@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm dust: report some message results directly back to user

Some messages (queryblock, countbadblocks, removebadblock) are best
reported directly to user directly. Do so with DMEMIT.

[Bryan: maintain __func__ output in DMEMIT messages]

Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Bryan Gurney <bgurney@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm dust: change ret to r in dust_map_write

In the dust_map_write() function, change the return code variable
"ret" to "r", to match the convention of the other device-mapper
targets.

Signed-off-by: Bryan Gurney <bgurney@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm dust: add limited write failure mode

Add a limited write failure mode which allows a write to a block to fail
a specified amount of times, prior to remapping. The "addbadblock"
message is extended to allow specifying the limited number of times a
write fails.

Example: add bad block on block 60, with 5 write failures:
dmsetup message 0 dust1 addbadblock 60 5

The write failure counter will be printed for newly added bad blocks.

Signed-off-by: Bryan Gurney <bgurney@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm dust: change ret to r in dust_map_read and dust_map

In the dust_map_read() and dust_map() functions, change the
return code variable "ret" to "r", to match the convention of the
other device-mapper targets.

Signed-off-by: Bryan Gurney <bgurney@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm dust: change result vars to r

Change the "result" variables to "r" in dust_status() and
dust_message().

Signed-off-by: Bryan Gurney <bgurney@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm dust: use dust block size for badblocklist index

Change the "frontend" dust_remove_block, dust_add_block, and
dust_query_block functions to store the "dust block number", instead
of the sector number corresponding to the "dust block number".

For the "backend" functions dust_map_read and dust_map_write,
right-shift by sect_per_block_shift. This fixes the inability to
emulate failure beyond the first sector of each "dust block" (for
devices with a "dust block size" larger than 512 bytes).

Fixes: e4f3fabd67480bf ("dm: add dust target")
Cc: stable@vger.kernel.org
Signed-off-by: Bryan Gurney <bgurney@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm dust: Make dm_dust_init and dm_dust_exit static

Fix sparse warnings:

drivers/md/dm-dust.c:495:12: warning: symbol 'dm_dust_init' was not declared. Should it be static?
drivers/md/dm-dust.c:505:13: warning: symbol 'dm_dust_exit' was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm dust: remove redundant unsigned comparison to less than zero

Variable block is an unsigned long long hence the less than zero
comparison is always false, hence it is redundant and can be removed.

Addresses-Coverity: ("Unsigned compared against 0")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Bryan Gurney <bgurney@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm: add dust target

Add the dm-dust target, which simulates the behavior of bad sectors
at arbitrary locations, and the ability to enable the emulation of
the read failures at an arbitrary time.

This target behaves similarly to a linear target. At a given time,
the user can send a message to the target to start failing read
requests on specific blocks. When the failure behavior is enabled,
reads of blocks configured "bad" will fail with EIO.

Writes of blocks configured "bad" will result in the following:

1. Remove the block from the "bad block list".
2. Successfully complete the write.

After this point, the block will successfully contain the written
data, and will service reads and writes normally. This emulates the
behavior of a "remapped sector" on a hard disk drive.

dm-dust provides logging of which blocks have been added or removed
to the "bad block list", as well as logging when a block has been
removed from the bad block list. These messages can be used
alongside the messages from the driver using a dm-dust device to
analyze the driver's behavior when a read fails at a given time.

(This logging can be reduced via a "quiet" mode, if desired.)

NOTE: If the block size is larger than 512 bytes, only the first sector
of each "dust block" is detected. Placing a limiting layer above a dust
target, to limit the minimum I/O size to the dust block size, will
ensure proper emulation of the given large block size.

Signed-off-by: Bryan Gurney <bgurney@redhat.com>
Co-developed-by: Joe Shimkus <jshimkus@redhat.com>
Co-developed-by: John Dorminy <jdorminy@redhat.com>
Co-developed-by: John Pittman <jpittman@redhat.com>
Co-developed-by: Thomas Jaskiewicz <tjaskiew@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>