The kvmalloc function fails with a warning if the size is larger than
INT_MAX. The warning was triggered by a syscall testing robot.

In order to avoid the warning, this commit limits the number of targets to
1048576 and the size of the parameter area to 1073741824.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

When zones were first added the SCSI and ATA specs, two different
models were supported (in addition to the drive managed one that
is invisible to the host):

 - host managed where non-conventional zones there is strict requirement
   to write at the write pointer, or else an error is returned
 - host aware where a write point is maintained if writes always happen
   at it, otherwise it is left in an under-defined state and the
   sequential write preferred zones behave like conventional zones
   (probably very badly performing ones, though)

Not surprisingly this lukewarm model didn't prove to be very useful and
was finally removed from the ZBC and SBC specs (NVMe never implemented
it).  Due to to the easily disappearing write pointer host software
could never rely on the write pointer to actually be useful for say
recovery.

Fortunately only a few HDD prototypes shipped using this model which
never made it to mass production.  Drop the support before it is too
late.  Note that any such host aware prototype HDD can still be used
with Linux as we'll now treat it as a conventional HDD.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20231217165359.604246-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dm-error is used in several test cases in the xfstests test suite to
check the handling of IO errors in file systems. However, with several
file systems getting native support for zoned block devices (e.g.
btrfs and f2fs), dm-error's lack of zoned block device support creates
problems as the file system attempts executing zone commands (e.g. a
zone append operation) against a dm-error non-zoned block device,
which causes various issues in the block layer (e.g. WARN_ON
triggers).

This commit adds supports for zoned block devices to dm-error, allowing
a DM device table containing an error target to be exposed as a zoned
block device (if all targets have a compatible zoned model support and
mapping). This is done as follows:
1) Allow passing 2 arguments to an error target, similar to dm-linear:
   a backing device and a start sector. These arguments are optional and
   dm-error retains its characteristics if the arguments are not
   specified.
2) Implement the iterate_devices method so that dm-core can normally
   check the zone support and restrictions (e.g. zone alignment of the
   targets). When the backing device arguments are not specified, the
   iterate_devices method never calls the fn() argument.
When no backing device is specified, as before, we assume that the DM
device is not zoned. When the backing device arguments are specified,
the zoned model of the DM device will depend on the backing device
type:
 - If the backing device is zoned and its model and mapping is
   compatible with other targets of the device, the resulting device
   will be zoned, with the dm-error mapped portion always returning
   errors (similar to the default non-zoned case).
 - If the backing device is not zoned, then the DM device will not be
   either.

This zone support for dm-error requires the definition of a functional
report_zones operation so that dm_revalidate_zones() can operate
correctly and resources for emulating zone append operations
initialized. This is necessary for cases where dm-error is used to
partially map a device and have an overall correct handling of zone
append. This means that dm-error does not fail report zones operations.

Two changes that are not obvious are included to avoid issues:
1) dm_table_supports_zoned_model() is changed to directly check if
   the backing device of a wildcard target (= dm-error target) is
   zoned. Otherwise, we wouldn't be able to catch the invalid setup of
   dm-error without a backing device (non zoned case) being combined
   with zoned targets.
2) dm_table_supports_dax() is modified to return false if the wildcard
   target is found. Otherwise, when dm-error is set without a backing
   device, we end up with a NULL pointer dereference in
   set_dax_synchronous (dax_dev is NULL). This is consistent with the
   current behavior because dm_table_supports_dax() always returned
   false for targets that do not define the iterate_devices method.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Tested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

There's a race condition in the multipath target when retrieve_deps
races with multipath_message calling dm_get_device and dm_put_device.
retrieve_deps walks the list of open devices without holding any lock
but multipath may add or remove devices to the list while it is
running. The end result may be memory corruption or use-after-free
memory access.

See this description of a UAF with multipath_message():
https://listman.redhat.com/archives/dm-devel/2022-October/052373.html

Fix this bug by introducing a new rw semaphore "devices_lock". We grab
devices_lock for read in retrieve_deps and we grab it for write in
dm_get_device and dm_put_device.

Reported-by: Luo Meng <luomeng12@huawei.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Tested-by: Li Lingfeng <lilingfeng3@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

The only overlap between the block open flags mapped into the fmode_t and
other uses of fmode_t are FMODE_READ and FMODE_WRITE.  Define a new
blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and
->ioctl and stop abusing fmode_t.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jack Wang <jinpu.wang@ionos.com>		[rnbd]
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

early_lookup_bdev is supposed to only be called from the early boot
code, but dm_get_device calls it as a general fallback when lookup_bdev
fails, which is problematic because early_lookup_bdev bypasses all normal
path based permission checking, and might cause problems with certain
container environments renaming devices.

Switch to only call early_lookup_bdev when dm is built-in and the system
state in not running yet.  This means it is still available when tables
are constructed by dm-init.c from the kernel command line, but not
otherwise.

Note that this strictly speaking changes the kernel ABI as the PARTUUID=
and PARTLABEL= style syntax is now not available during a running
systems.  They never were intended for that, but this breaks things
we'll have to figure out a way to make them available again.  But if
avoidable in any way I'd rather avoid that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20230531125535.676098-21-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Open code dm_get_dev_t in the only remaining caller, and propagate the
exact error code from lookup_bdev and early_lookup_bdev.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230531125535.676098-20-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

name_to_dev_t has a very misleading name, that doesn't make clear
it should only be used by the early init code, and also has a bad
calling convention that doesn't allow returning different kinds of
errors.  Rename it to early_lookup_bdev to make the use case clear,
and return an errno, where -EINVAL means the string could not be
parsed, and -ENODEV means it the string was valid, but there was
no device found for it.

Also stub out the whole call for !CONFIG_BLOCK as all the non-block
root cases are always covered in the caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230531125535.676098-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull device mapper updates from Mike Snitzer:

 - Split dm-bufio's rw_semaphore and rbtree. Offers improvements to
   dm-bufio's locking to allow increased concurrent IO -- particularly
   for read access for buffers already in dm-bufio's cache.

 - Also split dm-bio-prison-v1's spinlock and rbtree with comparable aim
   at improving concurrent IO (for the DM thinp target).

 - Both the dm-bufio and dm-bio-prison-v1 scaling of the number of locks
   and rbtrees used are managed by dm_num_hash_locks(). And the hash
   function used by both is dm_hash_locks_index().

 - Allow DM targets to require DISCARD, WRITE_ZEROES and SECURE_ERASE to
   be split at the target specified boundary (in terms of
   max_discard_sectors, max_write_zeroes_sectors and
   max_secure_erase_sectors respectively).

 - DM verity error handling fix for check_at_most_once on FEC.

 - Update DM verity target to emit audit events on verification failure
   and more.

 - DM core ->io_hints improvements needed in support of new discard
   support that is added to the DM "zero" and "error" targets.

 - Fix missing kmem_cache_destroy() call in initialization error path of
   both the DM integrity and DM clone targets.

 - A couple fixes for DM flakey, also add "error_reads" feature.

 - Fix DM core's resume to not lock FS when the DM map is NULL;
   otherwise initial table load can race with FS mount that takes
   superblock's ->s_umount rw_semaphore.

 - Various small improvements to both DM core and DM targets.

* tag 'for-6.4/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (40 commits)
  dm: don't lock fs when the map is NULL in process of resume
  dm flakey: add an "error_reads" option
  dm flakey: remove trailing space in the table line
  dm flakey: fix a crash with invalid table line
  dm ioctl: fix nested locking in table_clear() to remove deadlock concern
  dm: unexport dm_get_queue_limits()
  dm: allow targets to require splitting WRITE_ZEROES and SECURE_ERASE
  dm: add helper macro for simple DM target module init and exit
  dm raid: remove unused d variable
  dm: remove unnecessary (void*) conversions
  dm mirror: add DMERR message if alloc_workqueue fails
  dm: push error reporting down to dm_register_target()
  dm integrity: call kmem_cache_destroy() in dm_integrity_init() error path
  dm clone: call kmem_cache_destroy() in dm_clone_init() error path
  dm error: add discard support
  dm zero: add discard support
  dm table: allow targets without devices to set ->io_hints
  dm verity: emit audit events on verification failure and more
  dm verity: fix error handling for check_at_most_once on FEC
  dm: improve hash_locks sizing and hash function
  ...

In dm_calculate_queue_limits, add call to ->io_hints hook if the
target doesn't provide ->iterate_devices.

This is needed so the "error" and "zero" targets may support
discards. The 2 following commits will add their respective discard
support.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>