linux-stable.git/drivers/md/bcache, branch linux-5.18.y

bcache: memset on stack variables in bch_btree_check() and bch_sectors_dirty_init()

2022-07-02T14:44:55+00:00

commit 7d6b902ea0e02b2a25c480edf471cbaa4ebe6b3c upstream.

The local variables check_state (in bch_btree_check()) and state (in
bch_sectors_dirty_init()) should be fully filled by 0, because before
allocating them on stack, they were dynamically allocated by kzalloc().

Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20220527152818.27545-2-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

md: bcache: check the return value of kzalloc() in detached_dev_do_request()

2022-06-09T08:30:57+00:00

commit 40f567bbb3b0639d2ec7d1c6ad4b1b018f80cf19 upstream.

The function kzalloc() in detached_dev_do_request() can fail, so its
return value should be checked.

Fixes: bc082a55d25c ("bcache: fix inaccurate io state for detached bcache devices")
Reported-by: TOTE Robot 
Signed-off-by: Jia-Ju Bai 
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20220527152818.27545-4-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: avoid journal no-space deadlock by reserving 1 journal bucket

2022-06-09T08:30:53+00:00

commit 32feee36c30ea06e38ccb8ae6e5c44c6eec790a6 upstream.

The journal no-space deadlock was reported time to time. Such deadlock
can happen in the following situation.

When all journal buckets are fully filled by active jset with heavy
write I/O load, the cache set registration (after a reboot) will load
all active jsets and inserting them into the btree again (which is
called journal replay). If a journaled bkey is inserted into a btree
node and results btree node split, new journal request might be
triggered. For example, the btree grows one more level after the node
split, then the root node record in cache device super block will be
upgrade by bch_journal_meta() from bch_btree_set_root(). But there is no
space in journal buckets, the journal replay has to wait for new journal
bucket to be reclaimed after at least one journal bucket replayed. This
is one example that how the journal no-space deadlock happens.

The solution to avoid the deadlock is to reserve 1 journal bucket in
run time, and only permit the reserved journal bucket to be used during
cache set registration procedure for things like journal replay. Then
the journal space will never be fully filled, there is no chance for
journal no-space deadlock to happen anymore.

This patch adds a new member "bool do_reserve" in struct journal, it is
inititalized to 0 (false) when struct journal is allocated, and set to
1 (true) by bch_journal_space_reserve() when all initialization done in
run_cache_set(). In the run time when journal_reclaim() tries to
allocate a new journal bucket, free_journal_buckets() is called to check
whether there are enough free journal buckets to use. If there is only
1 free journal bucket and journal->do_reserve is 1 (true), the last
bucket is reserved and free_journal_buckets() will return 0 to indicate
no free journal bucket. Then journal_reclaim() will give up, and try
next time to see whetheer there is free journal bucket to allocate. By
this method, there is always 1 jouranl bucket reserved in run time.

During the cache set registration, journal->do_reserve is 0 (false), so
the reserved journal bucket can be used to avoid the no-space deadlock.

Reported-by: Nikhil Kshirsagar 
Signed-off-by: Coly Li 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220524102336.10684-5-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: remove incremental dirty sector counting for bch_sectors_dirty_init()

2022-06-09T08:30:53+00:00

commit 80db4e4707e78cb22287da7d058d7274bd4cb370 upstream.

After making bch_sectors_dirty_init() being multithreaded, the existing
incremental dirty sector counting in bch_root_node_dirty_init() doesn't
release btree occupation after iterating 500000 (INIT_KEYS_EACH_TIME)
bkeys. Because a read lock is added on btree root node to prevent the
btree to be split during the dirty sectors counting, other I/O requester
has no chance to gain the write lock even restart bcache_btree().

That is to say, the incremental dirty sectors counting is incompatible
to the multhreaded bch_sectors_dirty_init(). We have to choose one and
drop another one.

In my testing, with 512 bytes random writes, I generate 1.2T dirty data
and a btree with 400K nodes. With single thread and incremental dirty
sectors counting, it takes 30+ minites to register the backing device.
And with multithreaded dirty sectors counting, the backing device
registration can be accomplished within 2 minutes.

The 30+ minutes V.S. 2- minutes difference makes me decide to keep
multithreaded bch_sectors_dirty_init() and drop the incremental dirty
sectors counting. This is what this patch does.

But INIT_KEYS_EACH_TIME is kept, in sectors_dirty_init_fn() the CPU
will be released by cond_resched() after every INIT_KEYS_EACH_TIME keys
iterated. This is to avoid the watchdog reports a bogus soft lockup
warning.

Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded")
Signed-off-by: Coly Li 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220524102336.10684-4-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: improve multithreaded bch_sectors_dirty_init()

2022-06-09T08:30:53+00:00

commit 4dc34ae1b45fe26e772a44379f936c72623dd407 upstream.

Commit b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be
multithreaded") makes bch_sectors_dirty_init() to be much faster
when counting dirty sectors by iterating all dirty keys in the btree.
But it isn't in ideal shape yet, still can be improved.

This patch does the following changes to improve current parallel dirty
keys iteration on the btree,
- Add read lock to root node when multiple threads iterating the btree,
  to prevent the root node gets split by I/Os from other registered
  bcache devices.
- Remove local variable "char name[32]" and generate kernel thread name
  string directly when calling kthread_run().
- Allocate "struct bch_dirty_init_state state" directly on stack and
  avoid the unnecessary dynamic memory allocation for it.
- Decrease BCH_DIRTY_INIT_THRD_MAX from 64 to 12 which is enough indeed.
- Increase &state->started to count created kernel thread after it
  succeeds to create.
- When wait for all dirty key counting threads to finish, use
  wait_event() to replace wait_event_interruptible().

With the above changes, the code is more clear, and some potential error
conditions are avoided.

Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded")
Signed-off-by: Coly Li 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220524102336.10684-3-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: improve multithreaded bch_btree_check()

2022-06-09T08:30:53+00:00

commit 622536443b6731ec82c563aae7807165adbe9178 upstream.

Commit 8e7102273f59 ("bcache: make bch_btree_check() to be
multithreaded") makes bch_btree_check() to be much faster when checking
all btree nodes during cache device registration. But it isn't in ideal
shap yet, still can be improved.

This patch does the following thing to improve current parallel btree
nodes check by multiple threads in bch_btree_check(),
- Add read lock to root node while checking all the btree nodes with
  multiple threads. Although currently it is not mandatory but it is
  good to have a read lock in code logic.
- Remove local variable 'char name[32]', and generate kernel thread name
  string directly when calling kthread_run().
- Allocate local variable "struct btree_check_state check_state" on the
  stack and avoid unnecessary dynamic memory allocation for it.
- Reduce BCH_BTR_CHKTHREAD_MAX from 64 to 12 which is enough indeed.
- Increase check_state->started to count created kernel thread after it
  succeeds to create.
- When wait for all checking kernel threads to finish, use wait_event()
  to replace wait_event_interruptible().

With this change, the code is more clear, and some potential error
conditions are avoided.

Fixes: 8e7102273f59 ("bcache: make bch_btree_check() to be multithreaded")
Signed-off-by: Coly Li 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220524102336.10684-2-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: fix wrong bdev parameter when calling bio_alloc_clone() in do_bio_hook()

2022-04-19T17:28:17+00:00

Commit abfc426d1b2f ("block: pass a block_device to bio_clone_fast")
calls the modified bio_alloc_clone() in bcache code as:
	bio_init_clone(bio->bi_bdev, bio, orig_bio, GFP_NOIO);

But the first parameter is wrong, where bio->bi_bdev should be
orig_bio->bi_bdev. The wrong bi_bdev panics the kernel when submitting
cache bio.

This patch fixes the wrong bdev parameter usage and avoid the panic.

Fixes: abfc426d1b2f ("block: pass a block_device to bio_clone_fast")
Signed-off-by: Coly Li 
Cc: Christoph Hellwig 
Cc: Mike Snitzer 
Link: https://lore.kernel.org/r/20220419160425.4148-3-colyli@suse.de
Signed-off-by: Jens Axboe

bcache: put bch_bio_map() back to correct location in journal_write_unlocked()

2022-04-19T17:28:17+00:00

Commit a7c50c940477 ("block: pass a block_device and opf to bio_reset")
moves bch_bio_map() inside journal_write_unlocked() next to the location
where the modified bio_reset() was called.

This change is wrong because calling bch_bio_map() immediately after
bio_reset(), a BUG_ON(!bio->bi_iter.bi_size) inside bch_bio_map() will
be triggered and panic the kernel.

This patch puts bch_bio_map() back to its original correct location in
journal_write_unlocked() and avoid the BUG_ON().

Fixes: a7c50c940477 ("block: pass a block_device and opf to bio_reset")
Signed-off-by: Coly Li 
Cc: Christoph Hellwig 
Cc: Chaitanya Kulkarni 
Link: https://lore.kernel.org/r/20220419160425.4148-2-colyli@suse.de
Signed-off-by: Jens Axboe

Merge tag 'driver-core-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2022-03-28T19:41:28+00:00

Pull driver core updates from Greg KH:
 "Here is the set of driver core changes for 5.18-rc1.

  Not much here, primarily it was a bunch of cleanups and small updates:

   - kobj_type cleanups for default_groups

   - documentation updates

   - firmware loader minor changes

   - component common helper added and take advantage of it in many
     drivers (the largest part of this pull request).

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'driver-core-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (54 commits)
  Documentation: update stable review cycle documentation
  drivers/base/dd.c : Remove the initial value of the global variable
  Documentation: update stable tree link
  Documentation: add link to stable release candidate tree
  devres: fix typos in comments
  Documentation: add note block surrounding security patch note
  samples/kobject: Use sysfs_emit instead of sprintf
  base: soc: Make soc_device_match() simpler and easier to read
  driver core: dd: fix return value of __setup handler
  driver core: Refactor sysfs and drv/bus remove hooks
  driver core: Refactor multiple copies of device cleanup
  scripts: get_abi.pl: Fix typo in help message
  kernfs: fix typos in comments
  kernfs: remove unneeded #if 0 guard
  ALSA: hda/realtek: Make use of the helper component_compare_dev_name
  video: omapfb: dss: Make use of the helper component_compare_dev
  power: supply: ab8500: Make use of the helper component_compare_dev
  ASoC: codecs: wcd938x: Make use of the helper component_compare/release_of
  iommu/mediatek: Make use of the helper component_compare/release_of
  drm: of: Make use of the helper component_release_of
  ...

bcache: fixup multiple threads crash

2022-03-06T14:33:45+00:00

When multiple threads to check btree nodes in parallel, the main
thread wait for all threads to stop or CACHE_SET_IO_DISABLE flag:

wait_event_interruptible(check_state->wait,
                         atomic_read(&check_state->started) == 0 ||
                         test_bit(CACHE_SET_IO_DISABLE, &c->flags));

However, the bch_btree_node_read and bch_btree_node_read_done
maybe call bch_cache_set_error, then the CACHE_SET_IO_DISABLE
will be set. If the flag already set, the main thread return
error. At the same time, maybe some threads still running and
read NULL pointer, the kernel will crash.

This patch change the event wait condition, the main thread must
wait for all threads to stop.

Fixes: 8e7102273f597 ("bcache: make bch_btree_check() to be multithreaded")
Signed-off-by: Mingzhe Zou 
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Coly Li