dm-kcopyd doesn't access the allocated pages directly, it only passes
them to dm-io which adds them to a bio list - thus, we can allocate
the pages from high memory. This will reduce pressure on the low
memory when there are a large number of kcopyd jobs in progress.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
dm-writecache has the capability to limit the number of writeback jobs
in progress. However, this feature was off by default. As such there
were some out-of-memory crashes observed when lowering the low
watermark while the cache is full.
This commit enables writeback limit by default. It is set to 256MiB or
1/16 of total system memory, whichever is smaller.
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
The type name enum req_opf is misleading since it suggests that values of
this type include both an operation type and flags. Since values of this
type represent an operation only, change the type name into enum req_op.
Convert the enum req_op documentation into kernel-doc format. Move a few
definitions such that the enum req_op documentation occurs just above
the enum req_op definition.
The name "req_opf" was introduced by commit ef295ecf09 ("block: better op
and flags encoding").
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-2-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
LoadPin limits loading of kernel modules, firmware and certain
other files to a 'pinned' file system (typically a read-only
rootfs). To provide more flexibility LoadPin is being extended
to also allow loading these files from trusted dm-verity
devices. For that purpose LoadPin can be provided with a list
of verity root digests that it should consider as trusted.
Add a bunch of helpers to allow LoadPin to check whether a DM
device is a trusted verity device. The new functions broadly
fall in two categories: those that need access to verity
internals (like the root digest), and the 'glue' between
LoadPin and verity. The new file dm-verity-loadpin.c contains
the glue functions.
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/lkml/20220627083512.v7.1.I3e928575a23481121e73286874c4c2bdb403355d@changeid
Signed-off-by: Kees Cook <keescook@chromium.org>
Resolves: ERROR: else should follow close brace '}'
Signed-off-by: JeongHyeon Lee <jhs2.lee@samsung.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Rename from "tgt" to "ti" so that all of dm-table.c code uses the same
naming for dm_target variables.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
All callers of dm_table_get_target() are expected to do proper bounds
checking on the index they pass.
Move dm_table_get_target() to dm-core.h to make it extra clear that only
DM core code should be using it. Switch it to be inlined while at it.
Standardize all DM core callers to use the same for loop pattern and
make associated variables as local as possible. Rename some variables
(e.g. s/table/t/ and s/tgt/ti/) along the way.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Commit 61b6e2e532 ("dm: fix BLK_STS_DM_REQUEUE handling when dm_io
represents split bio") reverted DM core's bio splitting back to using
bio_split()+bio_chain() because it was found that otherwise DM's
BLK_STS_DM_REQUEUE would trigger a live-lock waiting for bio
completion that would never occur.
Restore using bio_trim()+bio_inc_remaining(), like was done in commit
7dd76d1fee ("dm: improve bio splitting and associated IO
accounting"), but this time with proper handling for the above
scenario that is covered in more detail in the commit header for
61b6e2e532.
Solve this issue by adding a two staged dm_io requeue mechanism that
uses the new dm_bio_rewind() via dm_io_rewind():
1) requeue the dm_io into the requeue_list added to struct
mapped_device, and schedule it via new added requeue work. This
workqueue just clones the dm_io->orig_bio (which DM saves and
ensures its end sector isn't modified). dm_io_rewind() uses the
sectors and sectors_offset members of the dm_io that are recorded
relative to the end of orig_bio: dm_bio_rewind()+bio_trim() are
then used to make that cloned bio reflect the subset of the
original bio that is represented by the dm_io that is being
requeued.
2) the 2nd stage requeue is same with original requeue, but
io->orig_bio points to new cloned bio (which matches the requeued
dm_io as described above).
This allows DM core to shift the need for bio cloning from bio-split
time (during IO submission) to the less likely BLK_STS_DM_REQUEUE
handling (after IO completes with that error).
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Commit 7759eb23fd ("block: remove bio_rewind_iter()") removed
a similar API for the following reasons:
```
It is pointed that bio_rewind_iter() is one very bad API[1]:
1) bio size may not be restored after rewinding
2) it causes some bogus change, such as 5151842b9d (block: reset
bi_iter.bi_done after splitting bio)
3) rewinding really makes things complicated wrt. bio splitting
4) unnecessary updating of .bi_done in fast path
[1] https://marc.info/?t=153549924200005&r=1&w=2
So this patch takes Kent's suggestion to restore one bio into its original
state via saving bio iterator(struct bvec_iter) in bio_integrity_prep(),
given now bio_rewind_iter() is only used by bio integrity code.
```
However, saving off a copy of the 32 bytes bio->bi_iter in case rewind
needed isn't efficient because it bloats per-bio-data for what is an
unlikely case. That suggestion also ignores the need to restore
crypto and integrity info.
Add dm_bio_rewind() API for a specific use-case that is much more narrow
than the previous more generic rewind code that was reverted:
1) most bios have a fixed end sector since bio split is done from front
of the bio, if driver just records how many sectors between current
bio's start sector and the original bio's end sector, the original
position can be restored. Keeping the original bio's end sector
fixed is a _hard_ requirement for this interface!
2) if a bio's end sector won't change (usually bio_trim() isn't
called, or in the case of DM it preserves original bio), user can
restore the original position by storing sector offset from the
current ->bi_iter.bi_sector to bio's end sector; together with
saving bio size, only 8 bytes is needed to restore to original
bio.
3) DM's requeue use case: when BLK_STS_DM_REQUEUE happens, DM core
needs to restore to an "original bio" which represents the current
dm_io to be requeued (which may be a subset of the original bio).
By storing the sector offset from the original bio's end sector and
dm_io's size, dm_bio_rewind() can restore such original bio. See
commit 7dd76d1fee ("dm: improve bio splitting and associated IO
accounting") for more details on how DM does this. Leveraging this,
allows DM core to shift the need for bio cloning from bio-split
time (during IO submission) to the less likely BLK_STS_DM_REQUEUE
handling (after IO completes with that error).
4) Unlike the original rewind API, dm_bio_rewind() doesn't add .bi_done
to bvec_iter and there is no effect on the fast path.
Implement dm_bio_rewind() by factoring out clear helpers that it calls:
dm_bio_integrity_rewind, dm_bio_crypt_rewind and dm_bio_rewind_iter.
DM is able to ensure that dm_bio_rewind() is used safely but, given
the constraint that the bio's end must never change, other
hypothetical future callers may not take the same care. So make
dm_bio_rewind() and all supporting code local to DM to avoid risk of
hypothetical abuse. A "dm_" prefix was added to all functions to avoid
any namespace collisions.
Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Currently shrinkers are anonymous objects. For debugging purposes they
can be identified by count/scan function names, but it's not always
useful: e.g. for superblock's shrinkers it's nice to have at least an
idea of to which superblock the shrinker belongs.
This commit adds names to shrinkers. register_shrinker() and
prealloc_shrinker() functions are extended to take a format and arguments
to master a name.
In some cases it's not possible to determine a good name at the time when
a shrinker is allocated. For such cases shrinker_debugfs_rename() is
provided.
The expected format is:
<subsystem>-<shrinker_type>[:<instance>]-<id>
For some shrinkers an instance can be encoded as (MAJOR:MINOR) pair.
After this change the shrinker debugfs directory looks like:
$ cd /sys/kernel/debug/shrinker/
$ ls
dquota-cache-16 sb-devpts-28 sb-proc-47 sb-tmpfs-42
mm-shadow-18 sb-devtmpfs-5 sb-proc-48 sb-tmpfs-43
mm-zspool:zram0-34 sb-hugetlbfs-17 sb-pstore-31 sb-tmpfs-44
rcu-kfree-0 sb-hugetlbfs-33 sb-rootfs-2 sb-tmpfs-49
sb-aio-20 sb-iomem-12 sb-securityfs-6 sb-tracefs-13
sb-anon_inodefs-15 sb-mqueue-21 sb-selinuxfs-22 sb-xfs:vda1-36
sb-bdev-3 sb-nsfs-4 sb-sockfs-8 sb-zsmalloc-19
sb-bpf-32 sb-pipefs-14 sb-sysfs-26 thp-deferred_split-10
sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-1 thp-zero-9
sb-cgroup2-30 sb-proc-39 sb-tmpfs-27 xfs-buf:vda1-37
sb-configfs-23 sb-proc-41 sb-tmpfs-29 xfs-inodegc:vda1-38
sb-dax-11 sb-proc-45 sb-tmpfs-35
sb-debugfs-7 sb-proc-46 sb-tmpfs-40
[roman.gushchin@linux.dev: fix build warnings]
Link: https://lkml.kernel.org/r/Yr+ZTnLb9lJk6fJO@castle
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lkml.kernel.org/r/20220601032227.4076670-4-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There's a KASAN warning in raid5_add_disk when running the LVM testsuite.
The warning happens in the test
lvconvert-raid-reshape-linear_to_raid6-single-type.sh. We fix the warning
by verifying that rdev->saved_raid_disk is within limits.
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
There's a KASAN warning in raid5_remove_disk when running the LVM
testsuite. We fix this warning by verifying that the "number" variable is
within limits.
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
If either BLK_STS_DM_REQUEUE or BLK_STS_AGAIN is returned for POLLED
io, we requeue the original bio into deferred list and kick md->wq to
re-submit it to block layer.
Improve the handling in the following way:
1) Factor out dm_handle_requeue() for handling dm_io requeue.
2) Unify handling for BLK_STS_DM_REQUEUE and BLK_STS_AGAIN: clear
REQ_POLLED for BLK_STS_DM_REQUEUE too, for the sake of simplicity,
given BLK_STS_DM_REQUEUE is very unusual.
3) Queue md->wq explicitly in dm_handle_requeue(), so requeue handling
becomes more robust.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
The current split between dm_table_alloc_md_mempools and
dm_alloc_md_mempools is rather arbitrary, so merge the two
into one easy to follow function.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
dm_get_reserved_rq_based_ios is only used in the core dm code, so
remove the export.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
On dm-raid table load (using raid_ctr), dm-raid allocates an array
rs->devs[rs->raid_disks] for the raid device members. rs->raid_disks
is defined by the number of raid metadata and image tupples passed
into the target's constructor.
In the case of RAID layout changes being requested, that number can be
different from the current number of members for existing raid sets as
defined in their superblocks. Example RAID layout changes include:
- raid1 legs being added/removed
- raid4/5/6/10 number of stripes changed (stripe reshaping)
- takeover to higher raid level (e.g. raid5 -> raid6)
When accessing array members, rs->raid_disks must be used in control
loops instead of the potentially larger value in rs->md.raid_disks.
Otherwise it will cause memory access beyond the end of the rs->devs
array.
Fix this by changing code that is prone to out-of-bounds access.
Also fix validate_raid_redundancy() to validate all devices that are
added. Also, use braces to help clean up raid_iterate_devices().
The out-of-bounds memory accesses was discovered using KASAN.
This commit was verified to pass all LVM2 RAID tests (with KASAN
enabled).
Cc: stable@vger.kernel.org
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Commit 85e123c27d ("dm mirror log: round up region bitmap size to
BITS_PER_LONG") introduced a regression on 64-bit architectures in the
lvm testsuite tests: lvcreate-mirror, mirror-names and vgsplit-operation.
If the device is shrunk, we need to clear log bits beyond the end of the
device. The code clears bits up to a 32-bit boundary and then calculates
lc->sync_count by summing set bits up to a 64-bit boundary (the commit
changed that; previously, this boundary was 32-bit too). So, it was using
some non-zeroed bits in the calculation and this caused misbehavior.
Fix this regression by clearing bits up to BITS_PER_LONG boundary.
Fixes: 85e123c27d ("dm mirror log: round up region bitmap size to BITS_PER_LONG")
Cc: stable@vger.kernel.org
Reported-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Commit 7dd76d1fee ("dm: improve bio splitting and associated IO
accounting") removed using cloned bio when dm io splitting is needed.
Using bio_trim()+bio_inc_remaining() rather than bio_split()+bio_chain()
causes multiple dm_io instances to share the same original bio, and it
works fine if IOs are completed successfully.
But a regression was caused for the case when BLK_STS_DM_REQUEUE is
returned from any one of DM's cloned bios (whose dm_io share the same
orig_bio). In this BLK_STS_DM_REQUEUE case only the mapped subset of
the original bio for the current exact dm_io needs to be re-submitted.
However, since the original bio is shared among all dm_io instances,
the ->orig_bio actually only represents the last dm_io instance, so
requeue can't work as expected. Also when more than one dm_io is
requeued, the same original bio is requeued from all dm_io's
completion handler, then race is caused.
Fix this issue by still allocating one clone bio for completing io
only, then io accounting can rely on ->orig_bio being unmodified. This
is needed because the dm_io's sector_offset and sectors members are
recorded relative to an unmodified ->orig_bio.
In the future, we can go back to using bio_trim()+bio_inc_remaining()
for dm's io splitting but then delay needing a bio clone only when
handling BLK_STS_DM_REQUEUE, but that approach is a bit complicated
(so it needs a development cycle):
1) bio clone needs to be done in task context
2) a block interface for unwinding bio is required
Fixes: 7dd76d1fee ("dm: improve bio splitting and associated IO accounting")
Reported-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Commit 5291984004 ("dm: fix bio polling to handle possibile
BLK_STS_AGAIN") inadvertently introduced an early return from
dm_io_complete() without first queueing the bio to DM if BLK_STS_AGAIN
occurs and bio-polling is _not_ being used.
Fix this by only returning early from dm_io_complete() if the bio has
first been properly queued to DM. Otherwise, the bio will never finish
via bio_endio.
Fixes: 5291984004 ("dm: fix bio polling to handle possibile BLK_STS_AGAIN")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
