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Pull more block updates from Jens Axboe:
- MD pull request via Song:
- Improve raid5 sequential IO performance on spinning disks, which
fixes a regression since v6.0 (Jan Kara)
- Fix bitmap offset types, which fixes an issue introduced in this
merge window (Jonathan Derrick)
- Cleanup of hweight type used for cgroup writeback (Maxim)
- Fix a regression with the "has_submit_bio" changes across partitions
(Ming)
- Cleanup of QUEUE_FLAG_ADD_RANDOM clearing.
We used to set this flag on queues non blk-mq queues, and hence some
drivers clear it unconditionally. Since all of these have since been
converted to true blk-mq drivers, drop the useless clear as the bit
is not set (Chaitanya)
- Fix the flags being set in a bio for a flush for drbd (Christoph)
- Cleanup and deduplication of the code handling setting block device
capacity (Damien)
- Fix for ublk handling IO timeouts (Ming)
- Fix for a regression in blk-cgroup teardown (Tao)
- NBD documentation and code fixes (Eric)
- Convert blk-integrity to using device_attributes rather than a second
kobject to manage lifetimes (Thomas)
* tag 'for-6.4/block-2023-05-06' of git://git.kernel.dk/linux:
ublk: add timeout handler
drbd: correctly submit flush bio on barrier
mailmap: add mailmap entries for Jens Axboe
block: Skip destroyed blkg when restart in blkg_destroy_all()
writeback: fix call of incorrect macro
md: Fix bitmap offset type in sb writer
md/raid5: Improve performance for sequential IO
docs nbd: userspace NBD now favors github over sourceforge
block nbd: use req.cookie instead of req.handle
uapi nbd: add cookie alias to handle
uapi nbd: improve doc links to userspace spec
blk-integrity: register sysfs attributes on struct device
blk-integrity: convert to struct device_attribute
blk-integrity: use sysfs_emit
block/drivers: remove dead clear of random flag
block: sync part's ->bd_has_submit_bio with disk's
block: Cleanup set_capacity()/bdev_set_nr_sectors()
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Bitmap offset is allowed to be negative, indicating that bitmap precedes
metadata. Change the type back from sector_t to loff_t to satisfy
conditionals and calculations.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/linux-raid/CAPhsuW6HuaUJ5WcyPajVgUfkQFYp2D_cy1g6qxN4CU_gP2=z7g@mail.gmail.com/
Fixes: 10172f200b67 ("md: Fix types in sb writer")
Signed-off-by: Jonathan Derrick <jonathan.derrick@linux.dev>
Suggested-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230425011438.71046-1-jonathan.derrick@linux.dev
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Commit 7e55c60acfbb ("md/raid5: Pivot raid5_make_request()") changed the
order in which requests for underlying disks are created. Since for
large sequential IO adding of requests frequently races with md_raid5
thread submitting bios to underlying disks, this results in a change in
IO pattern because intermediate states of new order of request creation
result in more smaller discontiguous requests. For RAID5 on top of three
rotational disks our performance testing revealed this results in
regression in write throughput:
iozone -a -s 131072000 -y 4 -q 8 -i 0 -i 1 -R
before 7e55c60acfbb:
KB reclen write rewrite read reread
131072000 4 493670 525964 524575 513384
131072000 8 540467 532880 512028 513703
after 7e55c60acfbb:
KB reclen write rewrite read reread
131072000 4 421785 456184 531278 509248
131072000 8 459283 456354 528449 543834
To reduce the amount of discontiguous requests we can start generating
requests with the stripe with the lowest chunk offset as that has the
best chance of being adjacent to IO queued previously. This improves the
performance to:
KB reclen write rewrite read reread
131072000 4 497682 506317 518043 514559
131072000 8 514048 501886 506453 504319
restoring big part of the regression.
Fixes: 7e55c60acfbb ("md/raid5: Pivot raid5_make_request()")
Cc: stable@vger.kernel.org # v6.0+
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230417171537.17899-1-jack@suse.cz
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QUEUE_FLAG_ADD_RANDOM is not set before we clear it for "null_blk",
"brd", "nbd", "zram", and "bcache" since by default we don't set
"QUEUE_FLAG_ADD_RANDOM" to MQ ops.
Remove dead clear of QUEUE_FLAG_ADD_RANDOM in above listed drivers.
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> #zram
Link: https://lore.kernel.org/r/20230424234628.45544-2-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
switching from a user process to a kernel thread.
- More folio conversions from Kefeng Wang, Zhang Peng and Pankaj
Raghav.
- zsmalloc performance improvements from Sergey Senozhatsky.
- Yue Zhao has found and fixed some data race issues around the
alteration of memcg userspace tunables.
- VFS rationalizations from Christoph Hellwig:
- removal of most of the callers of write_one_page()
- make __filemap_get_folio()'s return value more useful
- Luis Chamberlain has changed tmpfs so it no longer requires swap
backing. Use `mount -o noswap'.
- Qi Zheng has made the slab shrinkers operate locklessly, providing
some scalability benefits.
- Keith Busch has improved dmapool's performance, making part of its
operations O(1) rather than O(n).
- Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
permitting userspace to wr-protect anon memory unpopulated ptes.
- Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive
rather than exclusive, and has fixed a bunch of errors which were
caused by its unintuitive meaning.
- Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
which causes minor faults to install a write-protected pte.
- Vlastimil Babka has done some maintenance work on vma_merge():
cleanups to the kernel code and improvements to our userspace test
harness.
- Cleanups to do_fault_around() by Lorenzo Stoakes.
- Mike Rapoport has moved a lot of initialization code out of various
mm/ files and into mm/mm_init.c.
- Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
DRM, but DRM doesn't use it any more.
- Lorenzo has also coverted read_kcore() and vread() to use iterators
and has thereby removed the use of bounce buffers in some cases.
- Lorenzo has also contributed further cleanups of vma_merge().
- Chaitanya Prakash provides some fixes to the mmap selftesting code.
- Matthew Wilcox changes xfs and afs so they no longer take sleeping
locks in ->map_page(), a step towards RCUification of pagefaults.
- Suren Baghdasaryan has improved mmap_lock scalability by switching to
per-VMA locking.
- Frederic Weisbecker has reworked the percpu cache draining so that it
no longer causes latency glitches on cpu isolated workloads.
- Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
logic.
- Liu Shixin has changed zswap's initialization so we no longer waste a
chunk of memory if zswap is not being used.
- Yosry Ahmed has improved the performance of memcg statistics
flushing.
- David Stevens has fixed several issues involving khugepaged,
userfaultfd and shmem.
- Christoph Hellwig has provided some cleanup work to zram's IO-related
code paths.
- David Hildenbrand has fixed up some issues in the selftest code's
testing of our pte state changing.
- Pankaj Raghav has made page_endio() unneeded and has removed it.
- Peter Xu contributed some rationalizations of the userfaultfd
selftests.
- Yosry Ahmed has fixed an issue around memcg's page recalim
accounting.
- Chaitanya Prakash has fixed some arm-related issues in the
selftests/mm code.
- Longlong Xia has improved the way in which KSM handles hwpoisoned
pages.
- Peter Xu fixes a few issues with uffd-wp at fork() time.
- Stefan Roesch has changed KSM so that it may now be used on a
per-process and per-cgroup basis.
* tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
mm,unmap: avoid flushing TLB in batch if PTE is inaccessible
shmem: restrict noswap option to initial user namespace
mm/khugepaged: fix conflicting mods to collapse_file()
sparse: remove unnecessary 0 values from rc
mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area()
hugetlb: pte_alloc_huge() to replace huge pte_alloc_map()
maple_tree: fix allocation in mas_sparse_area()
mm: do not increment pgfault stats when page fault handler retries
zsmalloc: allow only one active pool compaction context
selftests/mm: add new selftests for KSM
mm: add new KSM process and sysfs knobs
mm: add new api to enable ksm per process
mm: shrinkers: fix debugfs file permissions
mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
migrate_pages_batch: fix statistics for longterm pin retry
userfaultfd: use helper function range_in_vma()
lib/show_mem.c: use for_each_populated_zone() simplify code
mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list()
fs/buffer: convert create_page_buffers to folio_create_buffers
fs/buffer: add folio_create_empty_buffers helper
...
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MAX_ORDER currently defined as number of orders page allocator supports:
user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
This definition is counter-intuitive and lead to number of bugs all over
the kernel.
Change the definition of MAX_ORDER to be inclusive: the range of orders
user can ask from buddy allocator is 0..MAX_ORDER now.
[kirill@shutemov.name: fix min() warning]
Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box
[akpm@linux-foundation.org: fix another min_t warning]
[kirill@shutemov.name: fixups per Zi Yan]
Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name
[akpm@linux-foundation.org: fix underlining in docs]
Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/
Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now there are no readers of shrinker_rwsem, so we can simply replace it
with mutex lock.
Link: https://lkml.kernel.org/r/20230313112819.38938-9-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill Tkhai <tkhai@ya.ru>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux
Pull sysctl updates from Luis Chamberlain:
"This only does a few sysctl moves from the kernel/sysctl.c file, the
rest of the work has been put towards deprecating two API calls which
incur recursion and prevent us from simplifying the registration
process / saving memory per move. Most of the changes have been
soaking on linux-next since v6.3-rc3.
I've slowed down the kernel/sysctl.c moves due to Matthew Wilcox's
feedback that we should see if we could *save* memory with these moves
instead of incurring more memory. We currently incur more memory since
when we move a syctl from kernel/sysclt.c out to its own file we end
up having to add a new empty sysctl used to register it. To achieve
saving memory we want to allow syctls to be passed without requiring
the end element being empty, and just have our registration process
rely on ARRAY_SIZE(). Without this, supporting both styles of sysctls
would make the sysctl registration pretty brittle, hard to read and
maintain as can be seen from Meng Tang's efforts to do just this [0].
Fortunately, in order to use ARRAY_SIZE() for all sysctl registrations
also implies doing the work to deprecate two API calls which use
recursion in order to support sysctl declarations with subdirectories.
And so during this development cycle quite a bit of effort went into
this deprecation effort. I've annotated the following two APIs are
deprecated and in few kernel releases we should be good to remove
them:
- register_sysctl_table()
- register_sysctl_paths()
During this merge window we should be able to deprecate and unexport
register_sysctl_paths(), we can probably do that towards the end of
this merge window.
Deprecating register_sysctl_table() will take a bit more time but this
pull request goes with a few example of how to do this.
As it turns out each of the conversions to move away from either of
these two API calls *also* saves memory. And so long term, all these
changes *will* prove to have saved a bit of memory on boot.
The way I see it then is if remove a user of one deprecated call, it
gives us enough savings to move one kernel/sysctl.c out from the
generic arrays as we end up with about the same amount of bytes.
Since deprecating register_sysctl_table() and register_sysctl_paths()
does not require maintainer coordination except the final unexport
you'll see quite a bit of these changes from other pull requests, I've
just kept the stragglers after rc3"
Link: https://lkml.kernel.org/r/ZAD+cpbrqlc5vmry@bombadil.infradead.org [0]
* tag 'sysctl-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (29 commits)
fs: fix sysctls.c built
mm: compaction: remove incorrect #ifdef checks
mm: compaction: move compaction sysctl to its own file
mm: memory-failure: Move memory failure sysctls to its own file
arm: simplify two-level sysctl registration for ctl_isa_vars
ia64: simplify one-level sysctl registration for kdump_ctl_table
utsname: simplify one-level sysctl registration for uts_kern_table
ntfs: simplfy one-level sysctl registration for ntfs_sysctls
coda: simplify one-level sysctl registration for coda_table
fs/cachefiles: simplify one-level sysctl registration for cachefiles_sysctls
xfs: simplify two-level sysctl registration for xfs_table
nfs: simplify two-level sysctl registration for nfs_cb_sysctls
nfs: simplify two-level sysctl registration for nfs4_cb_sysctls
lockd: simplify two-level sysctl registration for nlm_sysctls
proc_sysctl: enhance documentation
xen: simplify sysctl registration for balloon
md: simplify sysctl registration
hv: simplify sysctl registration
scsi: simplify sysctl registration with register_sysctl()
csky: simplify alignment sysctl registration
...
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register_sysctl_table() is a deprecated compatibility wrapper.
register_sysctl() can do the directory creation for you so just use
that.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Song Liu <song@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
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
...
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Commit fa247089de99 ("dm: requeue IO if mapping table not yet available")
added a detection of whether the mapping table is available in the IO
submission process. If the mapping table is unavailable, it returns
BLK_STS_RESOURCE and requeues the IO.
This can lead to the following deadlock problem:
dm create mount
ioctl(DM_DEV_CREATE_CMD)
ioctl(DM_TABLE_LOAD_CMD)
do_mount
vfs_get_tree
ext4_get_tree
get_tree_bdev
sget_fc
alloc_super
// got &s->s_umount
down_write_nested(&s->s_umount, ...);
ext4_fill_super
ext4_load_super
ext4_read_bh
submit_bio
// submit and wait io end
ioctl(DM_DEV_SUSPEND_CMD)
dev_suspend
do_resume
dm_suspend
__dm_suspend
lock_fs
freeze_bdev
get_active_super
grab_super
// wait for &s->s_umount
down_write(&s->s_umount);
dm_swap_table
__bind
// set md->map(can't get here)
IO will be continuously requeued while holding the lock since mapping
table is NULL. At the same time, mapping table won't be set since the
lock is not available.
Like request-based DM, bio-based DM also has the same problem.
It's not proper to just abort IO if the mapping table not available.
So clear DM_SKIP_LOCKFS_FLAG when the mapping table is NULL, this
allows the DM table to be loaded and the IO submitted upon resume.
Fixes: fa247089de99 ("dm: requeue IO if mapping table not yet available")
Cc: stable@vger.kernel.org
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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dm-flakey returns error on reads if no other argument is specified.
This commit simplifies associated logic while formalizing an
"error_reads" argument and an ERROR_READS flag.
If no argument is specified, set ERROR_READS flag so that it behaves
just like before this commit.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Don't return a trailing space in the output of STATUSTYPE_TABLE.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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This command will crash with NULL pointer dereference:
dmsetup create flakey --table \
"0 `blockdev --getsize /dev/ram0` flakey /dev/ram0 0 0 1 2 corrupt_bio_byte 512"
Fix the crash by checking if arg_name is non-NULL before comparing it.
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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syzkaller found the following problematic rwsem locking (with write
lock already held):
down_read+0x9d/0x450 kernel/locking/rwsem.c:1509
dm_get_inactive_table+0x2b/0xc0 drivers/md/dm-ioctl.c:773
__dev_status+0x4fd/0x7c0 drivers/md/dm-ioctl.c:844
table_clear+0x197/0x280 drivers/md/dm-ioctl.c:1537
In table_clear, it first acquires a write lock
https://elixir.bootlin.com/linux/v6.2/source/drivers/md/dm-ioctl.c#L1520
down_write(&_hash_lock);
Then before the lock is released at L1539, there is a path shown above:
table_clear -> __dev_status -> dm_get_inactive_table -> down_read
https://elixir.bootlin.com/linux/v6.2/source/drivers/md/dm-ioctl.c#L773
down_read(&_hash_lock);
It tries to acquire the same read lock again, resulting in the deadlock
problem.
Fix this by moving table_clear()'s __dev_status() call to after its
up_write(&_hash_lock);
Cc: stable@vger.kernel.org
Reported-by: Zheng Zhang <zheng.zhang@email.ucr.edu>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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There are no dm_get_queue_limits() callers outside of DM core and
there shouldn't be.
Also, remove its BUG_ON(!atomic_read(&md->holders)) to micro-optimize
__process_abnormal_io().
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Introduce max_write_zeroes_granularity and
max_secure_erase_granularity flags in the dm_target struct.
If a target sets these then DM core will split IO of these operation
types accordingly (in terms of max_write_zeroes_sectors and
max_secure_erase_sectors respectively).
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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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>
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clang with W=1 reports
drivers/md/dm-raid.c:2212:15: error: variable
'd' set but not used [-Werror,-Wunused-but-set-variable]
unsigned int d;
^
This variable is not used so remove it.
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Pointer variables of void * type do not require type cast.
Signed-off-by: Yu Zhe <yuzhe@nfschina.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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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>
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Otherwise the journal_io_cache will leak if dm_register_target() fails.
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Otherwise the _hydration_cache will leak if dm_register_target() fails.
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Add io_err_io_hints() and set discard limits so that the zero target
advertises support for discards.
The error target will return -EIO for discards.
This is useful when the user combines dm-error with other
discard-supporting targets in the same table; without dm-error
support, discards would be disabled for the whole combined device.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Add zero_io_hints() and set discard limits so that the zero target
advertises support for discards.
The zero target will ignore discards.
This is useful when the user combines dm-zero with other
discard-supporting targets in the same table; without dm-zero support,
discards would be disabled for the whole combined device.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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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>
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dm-verity signals integrity violations by returning I/O errors
to user space. To identify integrity violations by a controlling
instance, the kernel audit subsystem can be used to emit audit
events to user space. Analogous to dm-integrity, we also use the
dm-audit submodule allowing to emit audit events on verification
failures of metadata and data blocks as well as if max corrupted
errors are reached.
The construction and destruction of verity device mappings are
also relevant for auditing a system. Thus, those events are also
logged as audit events.
Tested by starting a container with the container manager (cmld) of
GyroidOS which uses a dm-verity protected rootfs image root.img mapped
to /dev/mapper/<uuid>-root. One block was manipulated in the
underlying image file and repeated reads of the verity device were
performed again until the max corrupted errors is reached, e.g.:
dd if=/dev/urandom of=root.img bs=512 count=1 seek=1000
for i in range {1..101}; do \
dd if=/dev/mapper/<uuid>-root of=/dev/null bs=4096 \
count=1 skip=1000 \
done
The resulting audit log looks as follows:
type=DM_CTRL msg=audit(1677618791.876:962):
module=verity op=ctr ppid=4876 pid=29102 auid=0 uid=0 gid=0
euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=44
comm="cmld" exe="/usr/sbin/cml/cmld" subj=unconfined
dev=254:3 error_msg='success' res=1
type=DM_EVENT msg=audit(1677619463.786:1074): module=verity
op=verify-data dev=7:0 sector=1000 res=0
...
type=DM_EVENT msg=audit(1677619596.727:1162): module=verity
op=verify-data dev=7:0 sector=1000 res=0
type=DM_EVENT msg=audit(1677619596.731:1163): module=verity
op=max-corrupted-errors dev=254:3 sector=? res=0
Signed-off-by: Michael Weiß <michael.weiss@aisec.fraunhofer.de>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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In verity_end_io(), if bi_status is not BLK_STS_OK, it can be return
directly. But if FEC configured, it is desired to correct the data page
through verity_verify_io. And the return value will be converted to
blk_status and passed to verity_finish_io().
BTW, when a bit is set in v->validated_blocks, verity_verify_io() skips
verification regardless of I/O error for the corresponding bio. In this
case, the I/O error could not be returned properly, and as a result,
there is a problem that abnormal data could be read for the
corresponding block.
To fix this problem, when an I/O error occurs, do not skip verification
even if the bit related is set in v->validated_blocks.
Fixes: 843f38d382b1 ("dm verity: add 'check_at_most_once' option to only validate hashes once")
Cc: stable@vger.kernel.org
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Yeongjin Gil <youngjin.gil@samsung.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Both bufio and bio-prison-v1 use the identical model for splitting
their respective locks and rbtrees. Improve dm_num_hash_locks() to
distribute across more rbtrees to improve overall performance -- but
the maximum number of locks/rbtrees is still 64.
Also factor out a common hash function named dm_hash_locks_index(),
the magic numbers used were determined to be best using this program:
https://gist.github.com/jthornber/e05c47daa7b500c56dc339269c5467fc
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Size the dm_bio_prison's number of prison_region structs using
dm_num_hash_locks().
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Add num_locks member to dm_bio_prison struct and use it rather than
the NR_LOCKS magic value (64).
Next commit will size the dm_bio_prison's prison_regions according to
dm_num_hash_locks().
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Size the dm_buffer_cache's number of buffer_tree structs using
dm_num_hash_locks().
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Add num_locks member to dm_buffer_cache struct and use it rather than
the NR_LOCKS magic value (64).
Next commit will size the dm_buffer_cache's buffer_trees according to
dm_num_hash_locks().
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Simple helper to use when DM core code needs to appropriately size,
based on num_online_cpus(), its data structures that split locks.
dm_num_hash_locks() rounds up num_online_cpus() to next power of 2
but caps return at DM_HASH_LOCKS_MAX (64).
This heuristic may evolve as warranted, but as-is it will serve as a
more informed basis for sizing the sharded lock structs in dm-bufio's
dm_buffer_cache (buffer_trees) and dm-bio-prison-v1's dm_bio_prison
(prison_regions).
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Don't have bio_detain() BUG_ON if a dm_cell_key is beyond
BIO_PRISON_MAX_RANGE or spans a boundary.
Update dm-thin.c:build_key() to use dm_cell_key_has_valid_range() which
will do this checking without using BUG_ON. Also update
process_discard_bio() to check the discard bio that DM core passes in
(having first imposed max_discard_granularity based splitting).
dm_cell_key_has_valid_range() will merely WARN_ON_ONCE if it returns
false because if it does: it is programmer error that should be caught
with proper testing. So relax the BUG_ONs to be WARN_ON_ONCE.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Split the bio prison into multiple regions, with a separate rbtree and
associated lock for each region.
To get fast bio prison locking and not damage the performance of
discards too much the bio-prison now stipulates that discards should
not cross a BIO_PRISON_MAX_RANGE boundary.
Because the range of a key (block_end - block_begin) must not exceed
BIO_PRISON_MAX_RANGE: break_up_discard_bio() now ensures the data
range reflected in PHYSICAL key doesn't exceed BIO_PRISON_MAX_RANGE.
And splitting the thin target's discards (handled with VIRTUAL key) is
achieved by updating dm-thin.c to set limits->max_discard_sectors in
terms of BIO_PRISON_MAX_RANGE _and_ setting the thin and thin-pool
targets' max_discard_granularity to true.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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The block core (bio_split_discard) will already split discards based
on the 'discard_granularity' and 'max_discard_sectors' queue_limits.
But the DM thin target also needs to ensure that it doesn't receive a
discard that spans a 'max_discard_sectors' boundary.
Introduce a dm_target 'max_discard_granularity' flag that if set will
cause DM core to split discard bios relative to 'max_discard_sectors'.
This treats 'discard_granularity' as a "min_discard_granularity" and
'max_discard_sectors' as a "max_discard_granularity".
Requested-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Reduce the time that a spinlock is held in cell_defer_no_holder().
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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The kernel supports multi page bio vector entries, so we can use them
in dm-bufio as an optimization.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Save one spinlock by using waitqueue_active. We hold the bufio lock at
this place, so no one can add entries to the waitqueue at this point.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Movement also consolidates holes in dm_bufio_client struct. But the
overall size of the struct isn't changed.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Sometimes it is beneficial to repeatedly get and drop locks as part of
an iteration. Introduce lock_history struct to help avoid redundant
drop and gets of the same lock.
Optimizes cache_iterate, cache_mark_many and cache_evict.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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When multiple threads perform IO to a thin device, the underlying
dm_bufio object can become a bottleneck; slowing down access to btree
nodes that store the thin metadata. Prior to this commit, each bufio
instance had a single mutex that was taken for every bufio operation.
This commit concentrates on improving the common case where: a user of
dm_bufio wishes to access, but not modify, a buffer which is already
within the dm_bufio cache.
Implementation::
The code has been refactored; pulling out an 'lru' abstraction and a
'buffer cache' abstraction (see 2 previous commits). This commit
updates higher level bufio code (that performs allocation of buffers,
IO and eviction/cache sizing) to leverage both abstractions. It also
deals with the delicate locking requirements of both abstractions to
provide finer grained locking. The result is significantly better
concurrent IO performance.
Before this commit, bufio has a global lru list it used to evict the
oldest, clean buffers from _all_ clients. With the new locking we
don’t want different ways to access the same buffer, so instead
do_global_cleanup() loops around the clients asking them to free
buffers older than a certain time.
This commit also converts many old BUG_ONs to WARN_ON_ONCE, see the
lru_evict and cache_evict code in particular. They will return
ER_DONT_EVICT if a given buffer somehow meets the invariants that
should _never_ happen. [Aside from revising this commit's header and
fixing coding style and whitespace nits: this switching to
WARN_ON_ONCE is Mike Snitzer's lone contribution to this commit]
Testing::
Some of the low level functions have been unit tested using dm-unit:
https://github.com/jthornber/dm-unit/blob/main/src/tests/bufio.rs
Higher level concurrency and IO is tested via a test only target
found here:
https://github.com/jthornber/linux/blob/2023-03-24-thin-concurrency-9/drivers/md/dm-bufio-test.c
The associated userland side of these tests is here:
https://github.com/jthornber/dmtest-python/blob/main/src/dmtest/bufio/bufio_tests.py
In addition the full dmtest suite of tests (dm-thin, dm-cache, etc)
has been run (~450 tests).
Performance::
Most bufio operations have unchanged performance. But if multiple
threads are attempting to get buffers concurrently, and these
buffers are already in the cache then there's a big speed up. Eg,
one test has 16 'hotspot' threads simulating btree lookups while
another thread dirties the whole device. In this case the hotspot
threads acquire the buffers about 25 times faster.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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The buffer cache is responsible for managing the holder count,
tracking clean/dirty state, and choosing buffers via predicates.
Higher level code is responsible for allocation of buffers, IO and
eviction/cache sizing.
The buffer cache has thread safe methods for acquiring a reference
to an existing buffer. All other methods in buffer cache are _not_
threadsafe, and only contain enough locking to guarantee the safe
methods.
Rather than a single mutex, sharded rw_semaphores are used to allow
concurrent threads to 'get' buffers. Each rw_semaphore protects its
own rbtree of buffer entries.
Code that uses this new dm_buffer_cache abstraction will be introduced
in a following commit.
This commit moves the dm_buffer struct in preparation for finer grained
dm_buffer changes, in the next commit, to be more easily seen. It also
introduces temporary dm_buffer struct members to allow compilation of
this intermediate commit (they will be elided in the next commit).
This commit will cause "defined but not used" compiler warnings that
will be resolved by the next commit.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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A CLOCK algorithm is used in this LRU abstraction. This avoids
relinking list nodes, which would require a write lock protecting it.
None of the LRU methods are threadsafe; locking must be done at a
higher level.
Code that uses this new LRU will be introduced in the next 2 commits.
As such, this commit will cause "defined but not used" compiler warnings
that will be resolved by the next 2 commits.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Reasonable to relax to WARN_ON because these are easily avoided but do
offer some assurance future coding mistakes won't occur (if changes
tested properly).
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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All these instances are entirely avoidable given that they speak to
coding mistakes that result in inappropriate use. Proper testing during
development will catch any such coding bug so its best to relax all of
these from BUG_ON to WARN_ON_ONCE.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Using BUG_ON when tearing down is excessive. Relax these to WARN_ONs.
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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Was used by multi-snapshot DM target that never went upstream.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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