linux-stable.git/drivers/md/bcache, branch v5.4.261

bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent

2023-08-11T09:53:44+00:00

[ Upstream commit 80fca8a10b604afad6c14213fdfd816c4eda3ee4 ]

In some specific situations, the return value of __bch_btree_node_alloc
may be NULL. This may lead to a potential NULL pointer dereference in
caller function like a calling chain :
btree_split->bch_btree_node_alloc->__bch_btree_node_alloc.

Fix it by initializing the return value in __bch_btree_node_alloc.

Fixes: cafe56359144 ("bcache: A block layer cache")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Wang 
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20230615121223.22502-6-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

bcache: remove 'int n' from parameter list of bch_bucket_alloc_set()

2023-08-11T09:53:44+00:00

[ Upstream commit 17e4aed8309ff28670271546c2c3263eb12f5eb6 ]

The parameter 'int n' from bch_bucket_alloc_set() is not cleared
defined. From the code comments n is the number of buckets to alloc, but
from the code itself 'n' is the maximum cache to iterate. Indeed all the
locations where bch_bucket_alloc_set() is called, 'n' is alwasy 1.

This patch removes the confused and unnecessary 'int n' from parameter
list of  bch_bucket_alloc_set(), and explicitly allocates only 1 bucket
for its caller.

Signed-off-by: Coly Li 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Jens Axboe 
Stable-dep-of: 80fca8a10b60 ("bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent")
Signed-off-by: Sasha Levin

bcache: Remove unnecessary NULL point check in node allocations

2023-07-27T06:37:25+00:00

commit 028ddcac477b691dd9205c92f991cc15259d033e upstream.

Due to the previous fix of __bch_btree_node_alloc, the return value will
never be a NULL pointer. So IS_ERR is enough to handle the failure
situation. Fix it by replacing IS_ERR_OR_NULL check by an IS_ERR check.

Fixes: cafe56359144 ("bcache: A block layer cache")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Wang 
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20230615121223.22502-5-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: fix set_at_max_writeback_rate() for multiple attached devices

2022-10-26T11:22:57+00:00

[ Upstream commit d2d05b88035d2d51a5bb6c5afec88a0880c73df4 ]

Inside set_at_max_writeback_rate() the calculation in following if()
check is wrong,
	if (atomic_inc_return(&c->idle_counter) <
	    atomic_read(&c->attached_dev_nr) * 6)

Because each attached backing device has its own writeback thread
running and increasing c->idle_counter, the counter increates much
faster than expected. The correct calculation should be,
	(counter / dev_nr) < dev_nr * 6
which equals to,
	counter < dev_nr * dev_nr * 6

This patch fixes the above mistake with correct calculation, and helper
routine idle_counter_exceeded() is added to make code be more clear.

Reported-by: Mingzhe Zou 
Signed-off-by: Coly Li 
Acked-by: Mingzhe Zou 
Link: https://lore.kernel.org/r/20220919161647.81238-6-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

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

2022-06-14T16:11:50+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: add proper error unwinding in bcache_device_init

2021-09-15T07:47:27+00:00

[ Upstream commit 224b0683228c5f332f9cee615d85e75e9a347170 ]

Except for the IDA none of the allocations in bcache_device_init is
unwound on error, fix that.

Signed-off-by: Christoph Hellwig 
Acked-by: Coly Li 
Link: https://lore.kernel.org/r/20210809064028.1198327-7-hch@lst.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

bcache: Move journal work to new flush wq

2021-03-04T09:26:43+00:00

commit afe78ab46f638ecdf80a35b122ffc92c20d9ae5d upstream.

This is potentially long running and not latency sensitive, let's get
it out of the way of other latency sensitive events.

As observed in the previous commit, the `system_wq` comes easily
congested by bcache, and this fixes a few more stalls I was observing
every once in a while.

Let's not make this `WQ_MEM_RECLAIM` as it showed to reduce performance
of boot and file system operations in my tests. Also, without
`WQ_MEM_RECLAIM`, I no longer see desktop stalls. This matches the
previous behavior as `system_wq` also does no memory reclaim:

> // workqueue.c:
> system_wq = alloc_workqueue("events", 0, 0);

Cc: Coly Li 
Cc: stable@vger.kernel.org # 5.4+
Signed-off-by: Kai Krakow 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: Give btree_io_wq correct semantics again

2021-03-04T09:26:42+00:00

commit d797bd9897e3559eb48d68368550d637d32e468c upstream.

Before killing `btree_io_wq`, the queue was allocated using
`create_singlethread_workqueue()` which has `WQ_MEM_RECLAIM`. After
killing it, it no longer had this property but `system_wq` is not
single threaded.

Let's combine both worlds and make it multi threaded but able to
reclaim memory.

Cc: Coly Li 
Cc: stable@vger.kernel.org # 5.4+
Signed-off-by: Kai Krakow 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

Revert "bcache: Kill btree_io_wq"

2021-03-04T09:26:42+00:00

commit 9f233ffe02e5cef611100cd8c5bcf4de26ca7bef upstream.

This reverts commit 56b30770b27d54d68ad51eccc6d888282b568cee.

With the btree using the `system_wq`, I seem to see a lot more desktop
latency than I should.

After some more investigation, it looks like the original assumption
of 56b3077 no longer is true, and bcache has a very high potential of
congesting the `system_wq`. In turn, this introduces laggy desktop
performance, IO stalls (at least with btrfs), and input events may be
delayed.

So let's revert this. It's important to note that the semantics of
using `system_wq` previously mean that `btree_io_wq` should be created
before and destroyed after other bcache wqs to keep the same
assumptions.

Cc: Coly Li 
Cc: stable@vger.kernel.org # 5.4+
Signed-off-by: Kai Krakow 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: fix a lost wake-up problem caused by mca_cannibalize_lock

2020-10-01T11:17:18+00:00

[ Upstream commit 34cf78bf34d48dddddfeeadb44f9841d7864997a ]

This patch fix a lost wake-up problem caused by the race between
mca_cannibalize_lock and bch_cannibalize_unlock.

Consider two processes, A and B. Process A is executing
mca_cannibalize_lock, while process B takes c->btree_cache_alloc_lock
and is executing bch_cannibalize_unlock. The problem happens that after
process A executes cmpxchg and will execute prepare_to_wait. In this
timeslice process B executes wake_up, but after that process A executes
prepare_to_wait and set the state to TASK_INTERRUPTIBLE. Then process A
goes to sleep but no one will wake up it. This problem may cause bcache
device to dead.

Signed-off-by: Guoju Fang 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin