linux-toradex.git/drivers/md/dm-integrity.c, branch v4.14

Merge tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2017-09-14T20:43:16+00:00

Pull device mapper updates from Mike Snitzer:

 - Some request-based DM core and DM multipath fixes and cleanups

 - Constify a few variables in DM core and DM integrity

 - Add bufio optimization and checksum failure accounting to DM
   integrity

 - Fix DM integrity to avoid checking integrity of failed reads

 - Fix DM integrity to use init_completion

 - A couple DM log-writes target fixes

 - Simplify DAX flushing by eliminating the unnecessary flush
   abstraction that was stood up for DM's use.

* tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dax: remove the pmem_dax_ops->flush abstraction
  dm integrity: use init_completion instead of COMPLETION_INITIALIZER_ONSTACK
  dm integrity: make blk_integrity_profile structure const
  dm integrity: do not check integrity for failed read operations
  dm log writes: fix >512b sectorsize support
  dm log writes: don't use all the cpu while waiting to log blocks
  dm ioctl: constify ioctl lookup table
  dm: constify argument arrays
  dm integrity: count and display checksum failures
  dm integrity: optimize writing dm-bufio buffers that are partially changed
  dm rq: do not update rq partially in each ending bio
  dm rq: make dm-sq requeuing behavior consistent with dm-mq behavior
  dm mpath: complain about unsupported __multipath_map_bio() return values
  dm mpath: avoid that building with W=1 causes gcc 7 to complain about fall-through

dm integrity: use init_completion instead of COMPLETION_INITIALIZER_ONSTACK

2017-09-11T15:00:54+00:00

The new lockdep support for completions causeed the stack usage
in dm-integrity to explode, in case of write_journal from 504 bytes
to 1120 (using arm gcc-7.1.1):

drivers/md/dm-integrity.c: In function 'write_journal':
drivers/md/dm-integrity.c:827:1: error: the frame size of 1120 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

The problem is that not only the size of 'struct completion' grows
significantly, but we end up having multiple copies of it on the stack
when we assign it from a local variable after the initial declaration.

COMPLETION_INITIALIZER_ONSTACK() is the right thing to use when we
want to declare and initialize a completion on the stack. However,
this driver doesn't do that and instead initializes the completion
just before it is used.

In this case, init_completion() does the same thing more efficiently,
and drops the stack usage for the function above down to 496 bytes.
While the other functions in this file are not bad enough to cause
a warning, they benefit equally from the change, so I do the change
across the entire file. In the one place where we reuse a completion,
I picked the cheaper reinit_completion() over init_completion().

Fixes: cd8084f91c02 ("locking/lockdep: Apply crossrelease to completions")
Signed-off-by: Arnd Bergmann 
Acked-by: Mikulas Patocka 
Acked-by: Mike Snitzer 
Signed-off-by: Mike Snitzer

dm integrity: make blk_integrity_profile structure const

2017-09-11T15:00:53+00:00

Make this structure const as it is only stored in the profile field of a
blk_integrity structure. This field is of type const, so make structure
as const.

Signed-off-by: Bhumika Goyal 
Signed-off-by: Mike Snitzer

dm integrity: do not check integrity for failed read operations

2017-09-11T14:07:34+00:00

Even though read operations fail, dm_integrity_map_continue() calls
integrity_metadata() to check integrity.  In this case, just complete
these.

This also makes it so read I/O errors do not generate integrity warnings
in the kernel log.

Cc: stable@vger.kernel.org
Signed-off-by: Hyunchul Lee 
Acked-by: Milan Broz 
Acked-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

dm: constify argument arrays

2017-08-28T15:47:18+00:00

The arrays of 'struct dm_arg' are never modified by the device-mapper
core, so constify them so that they are placed in .rodata.

(Exception: the args array in dm-raid cannot be constified because it is
allocated on the stack and modified.)

Signed-off-by: Eric Biggers 
Signed-off-by: Mike Snitzer

dm integrity: count and display checksum failures

2017-08-28T15:47:17+00:00

This changes DM integrity to count the number of checksum failures and
report the counter in response to STATUSTYPE_INFO request (via 'dmsetup
status').

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

dm integrity: optimize writing dm-bufio buffers that are partially changed

2017-08-28T15:47:17+00:00

Rather than write the entire dm-bufio buffer when only a subset is
changed, improve dm-bufio (and dm-integrity) by only writing the subset
of the buffer that changed.

Update dm-integrity to make use of dm-bufio's new
dm_bufio_mark_partial_buffer_dirty() interface.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

block: replace bi_bdev with a gendisk pointer and partitions index

2017-08-23T18:49:55+00:00

This way we don't need a block_device structure to submit I/O.  The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open.  Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).

For the actual I/O path all that we need is the gendisk, which exists
once per block device.  But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.

Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

dm integrity: test for corrupted disk format during table load

2017-07-25T14:11:14+00:00

If the dm-integrity superblock was corrupted in such a way that the
journal_sections field was zero, the integrity target would deadlock
because it would wait forever for free space in the journal.

Detect this situation and refuse to activate the device.

Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org
Fixes: 7eada909bfd7 ("dm: add integrity target")
Signed-off-by: Mike Snitzer

dm integrity: WARN_ON if variables representing journal usage get out of sync

2017-07-25T14:11:13+00:00

If this WARN_ON triggers it speaks to programmer error, and likely
implies corruption, but no released kernel should trigger it.  This
WARN_ON serves to assist DM integrity developers as changes are
made/tested in the future.

BUG_ON is excessive for catching programmer error, if a user or
developer would like warnings to trigger a panic, they can enable that
via /proc/sys/kernel/panic_on_warn

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer