[ Upstream commit 65f0f017e7 ]
For some block devices which large capacity (e.g. 8TB) but small io_opt
size (e.g. 8 sectors), in bcache_device_init() the stripes number calcu-
lated by,
DIV_ROUND_UP_ULL(sectors, d->stripe_size);
might be overflow to the unsigned int bcache_device->nr_stripes.
This patch uses the uint64_t variable to store DIV_ROUND_UP_ULL()
and after the value is checked to be available in unsigned int range,
sets it to bache_device->nr_stripes. Then the overflow is avoided.
Reported-and-tested-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Coly Li <colyli@suse.de>
Cc: stable@vger.kernel.org
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1783075
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e8abe1de43 ]
The error handling calls md_bitmap_free(bitmap) which checks for NULL
but will Oops if we pass an error pointer. Let's set "bitmap" to NULL
on this error path.
Fixes: afd7562860 ("md-cluster/raid10: resize all the bitmaps before start reshape")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e766668c6c ]
dm_stop_queue() only uses blk_mq_quiesce_queue() so it doesn't
formally stop the blk-mq queue; therefore there is no point making the
blk_mq_queue_stopped() check -- it will never be stopped.
In addition, even though dm_stop_queue() actually tries to quiesce hw
queues via blk_mq_quiesce_queue(), checking with blk_queue_quiesced()
to avoid unnecessary queue quiesce isn't reliable because: the
QUEUE_FLAG_QUIESCED flag is set before synchronize_rcu() and
dm_stop_queue() may be called when synchronize_rcu() from another
blk_mq_quiesce_queue() is in-progress.
Fixes: 7b17c2f729 ("dm: Fix a race condition related to stopping and starting queues")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 7a14812679 upstream.
offset_to_stripe() returns the stripe number (in type unsigned int) from
an offset (in type uint64_t) by the following calculation,
do_div(offset, d->stripe_size);
For large capacity backing device (e.g. 18TB) with small stripe size
(e.g. 4KB), the result is 4831838208 and exceeds UINT_MAX. The actual
returned value which caller receives is 536870912, due to the overflow.
Indeed in bcache_device_init(), bcache_device->nr_stripes is limited in
range [1, INT_MAX]. Therefore all valid stripe numbers in bcache are
in range [0, bcache_dev->nr_stripes - 1].
This patch adds a upper limition check in offset_to_stripe(): the max
valid stripe number should be less than bcache_device->nr_stripes. If
the calculated stripe number from do_div() is equal to or larger than
bcache_device->nr_stripe, -EINVAL will be returned. (Normally nr_stripes
is less than INT_MAX, exceeding upper limitation doesn't mean overflow,
therefore -EOVERFLOW is not used as error code.)
This patch also changes nr_stripes' type of struct bcache_device from
'unsigned int' to 'int', and return value type of offset_to_stripe()
from 'unsigned int' to 'int', to match their exact data ranges.
All locations where bcache_device->nr_stripes and offset_to_stripe() are
referenced also get updated for the above type change.
Reported-and-tested-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Coly Li <colyli@suse.de>
Cc: stable@vger.kernel.org
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1783075
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5fe4886785 upstream.
There are some meta data of bcache are allocated by multiple pages,
and they are used as bio bv_page for I/Os to the cache device. for
example cache_set->uuids, cache->disk_buckets, journal_write->data,
bset_tree->data.
For such meta data memory, all the allocated pages should be treated
as a single memory block. Then the memory management and underlying I/O
code can treat them more clearly.
This patch adds __GFP_COMP flag to all the location allocating >0 order
pages for the above mentioned meta data. Then their pages are treated
as compound pages now.
Signed-off-by: Coly Li <colyli@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a1c6ae3d9f upstream.
In degraded raid5, we need to read parity to do reconstruct-write when
data disks fail. However, we can not read parity from
handle_stripe_dirtying() in force reconstruct-write mode.
Reproducible Steps:
1. Create degraded raid5
mdadm -C /dev/md2 --assume-clean -l5 -n3 /dev/sda2 /dev/sdb2 missing
2. Set rmw_level to 0
echo 0 > /sys/block/md2/md/rmw_level
3. IO to raid5
Now some io may be stuck in raid5. We can use handle_stripe_fill() to read
the parity in this situation.
Cc: <stable@vger.kernel.org> # v4.4+
Reviewed-by: Alex Wu <alexwu@synology.com>
Reviewed-by: BingJing Chang <bingjingc@synology.com>
Reviewed-by: Danny Shih <dannyshih@synology.com>
Signed-off-by: ChangSyun Peng <allenpeng@synology.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 117f636ea6 ]
In register_cache_set(), c is pointer to struct cache_set, and ca is
pointer to struct cache, if ca->sb.seq > c->sb.seq, it means this
registering cache has up to date version and other members, the in-
memory version and other members should be updated to the newer value.
But current implementation makes a cache set only has a single cache
device, so the above assumption works well except for a special case.
The execption is when a cache device new created and both ca->sb.seq and
c->sb.seq are 0, because the super block is never flushed out yet. In
the location for the following if() check,
2156 if (ca->sb.seq > c->sb.seq) {
2157 c->sb.version = ca->sb.version;
2158 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16);
2159 c->sb.flags = ca->sb.flags;
2160 c->sb.seq = ca->sb.seq;
2161 pr_debug("set version = %llu\n", c->sb.version);
2162 }
c->sb.version is not initialized yet and valued 0. When ca->sb.seq is 0,
the if() check will fail (because both values are 0), and the cache set
version, set_uuid, flags and seq won't be updated.
The above problem is hiden for current code, because the bucket size is
compatible among different super block version. And the next time when
running cache set again, ca->sb.seq will be larger than 0 and cache set
super block version will be updated properly.
But if the large bucket feature is enabled, sb->bucket_size is the low
16bits of the bucket size. For a power of 2 value, when the actual
bucket size exceeds 16bit width, sb->bucket_size will always be 0. Then
read_super_common() will fail because the if() check to
is_power_of_2(sb->bucket_size) is false. This is how the long time
hidden bug is triggered.
This patch modifies the if() check to the following way,
2156 if (ca->sb.seq > c->sb.seq || c->sb.seq == 0) {
Then cache set's version, set_uuid, flags and seq will always be updated
corectly including for a new created cache device.
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9a5a85972c ]
Pointer mddev is being dereferenced with a test_bit call before mddev
is being null checked, this may cause a null pointer dereference. Fix
this by moving the null pointer checks to sanity check mddev before
it is dereferenced.
Addresses-Coverity: ("Dereference before null check")
Fixes: 62f7b1989c ("md raid0/linear: Mark array as 'broken' and fail BIOs if a member is gone")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Guilherme G. Piccoli <gpiccoli@canonical.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 5df96f2b9f upstream.
Commit adc0daad36 ("dm: report suspended
device during destroy") broke integrity recalculation.
The problem is dm_suspended() returns true not only during suspend,
but also during resume. So this race condition could occur:
1. dm_integrity_resume calls queue_work(ic->recalc_wq, &ic->recalc_work)
2. integrity_recalc (&ic->recalc_work) preempts the current thread
3. integrity_recalc calls if (unlikely(dm_suspended(ic->ti))) goto unlock_ret;
4. integrity_recalc exits and no recalculating is done.
To fix this race condition, add a function dm_post_suspending that is
only true during the postsuspend phase and use it instead of
dm_suspended().
Signed-off-by: Mikulas Patocka <mpatocka redhat com>
Fixes: adc0daad36 ("dm: report suspended device during destroy")
Cc: stable vger kernel org # v4.18+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 382761dc63 ]
bio_uninit is the proper API to clean up a BIO that has been allocated
on stack or inside a structure that doesn't come from the BIO allocator.
Switch dm to use that instead of bio_disassociate_blkg, which really is
an implementation detail. Note that the bio_uninit calls are also moved
to the two callers of __send_empty_flush, so that they better pair with
the bio_init calls used to initialize them.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 6958c1c640 upstream.
kobject_uevent may allocate memory and it may be called while there are dm
devices suspended. The allocation may recurse into a suspended device,
causing a deadlock. We must set the noio flag when sending a uevent.
The observed deadlock was reported here:
https://www.redhat.com/archives/dm-devel/2020-March/msg00025.html
Reported-by: Khazhismel Kumykov <khazhy@google.com>
Reported-by: Tahsin Erdogan <tahsin@google.com>
Reported-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7b23774867 upstream.
The unit of max_io_len is sector instead of byte (spotted through
code review), so fix it.
Fixes: 3b1a94c88b ("dm zoned: drive-managed zoned block device target")
Cc: stable@vger.kernel.org
Signed-off-by: Hou Tao <houtao1@huawei.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d35bd764e6 upstream.
Add cond_resched() to a loop that fills in the mapper memory area
because the loop can be executed many times.
Fixes: 48debafe4f ("dm: add writecache target")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit be23e83733 ]
coccicheck reports:
drivers/md//bcache/btree.c:1538:1-7: preceding lock on line 1417
In btree_gc_coalesce func, if the coalescing process fails, we will goto
to out_nocoalesce tag directly without releasing new_nodes[i]->write_lock.
Then, it will cause a deadlock when trying to acquire new_nodes[i]->
write_lock for freeing new_nodes[i] before return.
btree_gc_coalesce func details as follows:
if alloc new_nodes[i] fails:
goto out_nocoalesce;
// obtain new_nodes[i]->write_lock
mutex_lock(&new_nodes[i]->write_lock)
// main coalescing process
for (i = nodes - 1; i > 0; --i)
[snipped]
if coalescing process fails:
// Here, directly goto out_nocoalesce
// tag will cause a deadlock
goto out_nocoalesce;
[snipped]
// release new_nodes[i]->write_lock
mutex_unlock(&new_nodes[i]->write_lock)
// coalesing succ, return
return;
out_nocoalesce:
btree_node_free(new_nodes[i]) // free new_nodes[i]
// obtain new_nodes[i]->write_lock
mutex_lock(&new_nodes[i]->write_lock);
// set flag for reuse
clear_bit(BTREE_NODE_dirty, &ew_nodes[i]->flags);
// release new_nodes[i]->write_lock
mutex_unlock(&new_nodes[i]->write_lock);
To fix the problem, we add a new tag 'out_unlock_nocoalesce' for
releasing new_nodes[i]->write_lock before out_nocoalesce tag. If
coalescing process fails, we will go to out_unlock_nocoalesce tag
for releasing new_nodes[i]->write_lock before free new_nodes[i] in
out_nocoalesce tag.
(Coly Li helps to clean up commit log format.)
Fixes: 2a285686c1 ("bcache: btree locking rework")
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 489dc0f06a ]
The only case where dmz_get_zone_for_reclaim() cannot return a zone is
if the respective lists are empty. So we should just return a simple
NULL value here as we really don't have an error code which would make
sense.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2361ae5953 ]
SCSI LUN passthrough code such as qemu's "scsi-block" device model
pass every IO to the host via SG_IO ioctls. Currently, dm-multipath
calls choose_pgpath() only in the block IO code path, not in the ioctl
code path (unless current_pgpath is NULL). This has the effect that no
path switching and thus no load balancing is done for SCSI-passthrough
IO, unless the active path fails.
Fix this by using the same logic in multipath_prepare_ioctl() as in
multipath_clone_and_map().
Note: The allegedly best path selection algorithm, service-time,
still wouldn't work perfectly, because the io size of the current
request is always set to 0. Changing that for the IO passthrough
case would require the ioctl cmd and arg to be passed to dm's
prepare_ioctl() method.
Signed-off-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 64611a15ca upstream.
queue_limits::logical_block_size got changed from unsigned short to
unsigned int, but it was forgotten to update crypt_io_hints() to use the
new type. Fix it.
Fixes: ad6bf88a6c ("block: fix an integer overflow in logical block size")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 86da9f7367 ]
The problematic code piece in bcache_device_free() is,
785 static void bcache_device_free(struct bcache_device *d)
786 {
787 struct gendisk *disk = d->disk;
[snipped]
799 if (disk) {
800 if (disk->flags & GENHD_FL_UP)
801 del_gendisk(disk);
802
803 if (disk->queue)
804 blk_cleanup_queue(disk->queue);
805
806 ida_simple_remove(&bcache_device_idx,
807 first_minor_to_idx(disk->first_minor));
808 put_disk(disk);
809 }
[snipped]
816 }
At line 808, put_disk(disk) may encounter kobject refcount of 'disk'
being underflow.
Here is how to reproduce the issue,
- Attche the backing device to a cache device and do random write to
make the cache being dirty.
- Stop the bcache device while the cache device has dirty data of the
backing device.
- Only register the backing device back, NOT register cache device.
- The bcache device node /dev/bcache0 won't show up, because backing
device waits for the cache device shows up for the missing dirty
data.
- Now echo 1 into /sys/fs/bcache/pendings_cleanup, to stop the pending
backing device.
- After the pending backing device stopped, use 'dmesg' to check kernel
message, a use-after-free warning from KASA reported the refcount of
kobject linked to the 'disk' is underflow.
The dropping refcount at line 808 in the above code piece is added by
add_disk(d->disk) in bch_cached_dev_run(). But in the above condition
the cache device is not registered, bch_cached_dev_run() has no chance
to be called and the refcount is not added. The put_disk() for a non-
added refcount of gendisk kobject triggers a underflow warning.
This patch checks whether GENHD_FL_UP is set in disk->flags, if it is
not set then the bcache device was not added, don't call put_disk()
and the the underflow issue can be avoided.
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ba54d4d4d2 ]
Using GFP_NOIO flag to call scribble_alloc() from resize_chunk() does
not have the expected behavior. kvmalloc_array() inside scribble_alloc()
which receives the GFP_NOIO flag will eventually call kmalloc_node() to
allocate physically continuous pages.
Now we have memalloc scope APIs in mddev_suspend()/mddev_resume() to
prevent memory reclaim I/Os during raid array suspend context, calling
to kvmalloc_array() with GFP_KERNEL flag may avoid deadlock of recursive
I/O as expected.
This patch removes the useless gfp flags from parameters list of
scribble_alloc(), and call kvmalloc_array() with GFP_KERNEL flag. The
incorrect GFP_NOIO flag does not exist anymore.
Fixes: b330e6a49d ("md: convert to kvmalloc")
Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 31b2212019 upstream.
The dm-writecache reads metadata in the target constructor. However, when
we reload the target, there could be another active instance running on
the same device. This is the sequence of operations when doing a reload:
1. construct new target
2. suspend old target
3. resume new target
4. destroy old target
Metadata that were written by the old target between steps 1 and 2 would
not be visible by the new target.
Fix the data corruption by loading the metadata in the resume handler.
Also, validate block_size is at least as large as both the devices'
logical block size and only read 1 block from the metadata during
target constructor -- no need to read entirety of metadata now that it
is done during resume.
Fixes: 48debafe4f ("dm: add writecache target")
Cc: stable@vger.kernel.org # v4.18+
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ad4e80a639 upstream.
The error correction data is computed as if data and hash blocks
were concatenated. But hash block number starts from v->hash_start.
So, we have to calculate hash block number based on that.
Fixes: a739ff3f54 ("dm verity: add support for forward error correction")
Cc: stable@vger.kernel.org
Signed-off-by: Sunwook Eom <speed.eom@samsung.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 9fc06ff568 ]
Add missing casts when converting from regions to sectors.
In case BITS_PER_LONG == 32, the lack of the appropriate casts can lead
to overflows and miscalculation of the device sector.
As a result, we could end up discarding and/or copying the wrong parts
of the device, thus corrupting the device's data.
Fixes: 7431b7835f ("dm: add clone target")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4b5142905d ]
There is a bug in the way dm-clone handles discards, which can lead to
discarding the wrong blocks or trying to discard blocks beyond the end
of the device.
This could lead to data corruption, if the destination device indeed
discards the underlying blocks, i.e., if the discard operation results
in the original contents of a block to be lost.
The root of the problem is the code that calculates the range of regions
covered by a discard request and decides which regions to discard.
Since dm-clone handles the device in units of regions, we don't discard
parts of a region, only whole regions.
The range is calculated as:
rs = dm_sector_div_up(bio->bi_iter.bi_sector, clone->region_size);
re = bio_end_sector(bio) >> clone->region_shift;
, where 'rs' is the first region to discard and (re - rs) is the number
of regions to discard.
The bug manifests when we try to discard part of a single region, i.e.,
when we try to discard a block with size < region_size, and the discard
request both starts at an offset with respect to the beginning of that
region and ends before the end of the region.
The root cause is the following comparison:
if (rs == re)
// skip discard and complete original bio immediately
, which doesn't take into account that 'rs' might be greater than 're'.
Thus, we then issue a discard request for the wrong blocks, instead of
skipping the discard all together.
Fix the check to also take into account the above case, so we don't end
up discarding the wrong blocks.
Also, add some range checks to dm_clone_set_region_hydrated() and
dm_clone_cond_set_range(), which update dm-clone's region bitmap.
Note that the aforementioned bug doesn't cause invalid memory accesses,
because dm_clone_is_range_hydrated() returns True for this case, so the
checks are just precautionary.
Fixes: 7431b7835f ("dm: add clone target")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6ca43ed837 ]
If we are in a place where it is known that interrupts are enabled,
functions spin_lock_irq/spin_unlock_irq should be used instead of
spin_lock_irqsave/spin_unlock_irqrestore.
spin_lock_irq and spin_unlock_irq are faster because they don't need to
push and pop the flags register.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b8fdd09037 ]
zmd->nr_rnd_zones was increased twice by mistake. The other place it
is increased in dmz_init_zone() is the only one needed:
1131 zmd->nr_useable_zones++;
1132 if (dmz_is_rnd(zone)) {
1133 zmd->nr_rnd_zones++;
^^^
Fixes: 3b1a94c88b ("dm zoned: drive-managed zoned block device target")
Cc: stable@vger.kernel.org
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 81d5553d12 upstream.
dm_clone_nr_of_hydrated_regions() returns the number of regions that
have been hydrated so far. In order to do so it employs bitmap_weight().
Until now, the return type of dm_clone_nr_of_hydrated_regions() was
unsigned long.
Because bitmap_weight() returns an int, in case BITS_PER_LONG == 64 and
the return value of bitmap_weight() is 2^31 (the maximum allowed number
of regions for a device), the result is sign extended from 32 bits to 64
bits and an incorrect value is displayed, in the status output of
dm-clone, as the number of hydrated regions.
Fix this by having dm_clone_nr_of_hydrated_regions() return an unsigned
int.
Fixes: 7431b7835f ("dm: add clone target")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit cd481c1226 upstream.
Add overflow check for clone->nr_regions variable, which holds the
number of regions of the target.
The overflow can occur with sufficiently large devices, if BITS_PER_LONG
== 32. E.g., if the region size is 8 sectors (4K), the overflow would
occur for device sizes > 34359738360 sectors (~16TB).
This could result in multiple device sectors wrongly mapping to the same
region number, due to the truncation from 64 bits to 32 bits, which
would lead to data corruption.
Fixes: 7431b7835f ("dm: add clone target")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b93b6643e9 upstream.
If the user specifies tag size larger than HASH_MAX_DIGESTSIZE,
there's a crash in integrity_metadata().
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1edaa447d9 upstream.
Initializing a dm-writecache device can take a long time when the
persistent memory device is large. Add cond_resched() to a few loops
to avoid warnings that the CPU is stuck.
Cc: stable@vger.kernel.org # v4.18+
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 6b40bec3b1 ]
Don't call quiesce(1) and quiesce(0) if array is already suspended,
otherwise in level_store, the array is writable after mddev_detach
in below part though the intention is to make array writable after
resume.
mddev_suspend(mddev);
mddev_detach(mddev);
...
mddev_resume(mddev);
And it also causes calltrace as follows in [1].
[48005.653834] WARNING: CPU: 1 PID: 45380 at kernel/kthread.c:510 kthread_park+0x77/0x90
[...]
[48005.653976] CPU: 1 PID: 45380 Comm: mdadm Tainted: G OE 5.4.10-arch1-1 #1
[48005.653979] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./J4105-ITX, BIOS P1.40 08/06/2018
[48005.653984] RIP: 0010:kthread_park+0x77/0x90
[48005.654015] Call Trace:
[48005.654039] r5l_quiesce+0x3c/0x70 [raid456]
[48005.654052] raid5_quiesce+0x228/0x2e0 [raid456]
[48005.654073] mddev_detach+0x30/0x70 [md_mod]
[48005.654090] level_store+0x202/0x670 [md_mod]
[48005.654099] ? security_capable+0x40/0x60
[48005.654114] md_attr_store+0x7b/0xc0 [md_mod]
[48005.654123] kernfs_fop_write+0xce/0x1b0
[48005.654132] vfs_write+0xb6/0x1a0
[48005.654138] ksys_write+0x67/0xe0
[48005.654146] do_syscall_64+0x4e/0x140
[48005.654155] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[48005.654161] RIP: 0033:0x7fa0c8737497
[1]: https://bugzilla.kernel.org/show_bug.cgi?id=206161
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 120c9257f5 upstream.
This reverts commit effd58c95f.
blk_queue_split() is causing excessive IO splitting -- because
blk_max_size_offset() depends on 'chunk_sectors' limit being set and
if it isn't (as is the case for DM targets!) it falls back to
splitting on a 'max_sectors' boundary regardless of offset.
"Fix" this by reverting back to _not_ using blk_queue_split() in
dm_process_bio() for normal IO (reads and writes). Long-term fix is
still TBD but it should focus on training blk_max_size_offset() to
call into a DM provided hook (to call DM's max_io_len()).
Test results from simple misaligned IO test on 4-way dm-striped device
with chunksize of 128K and stripesize of 512K:
xfs_io -d -c 'pread -b 2m 224s 4072s' /dev/mapper/stripe_dev
before this revert:
253,0 21 1 0.000000000 2206 Q R 224 + 4072 [xfs_io]
253,0 21 2 0.000008267 2206 X R 224 / 480 [xfs_io]
253,0 21 3 0.000010530 2206 X R 224 / 256 [xfs_io]
253,0 21 4 0.000027022 2206 X R 480 / 736 [xfs_io]
253,0 21 5 0.000028751 2206 X R 480 / 512 [xfs_io]
253,0 21 6 0.000033323 2206 X R 736 / 992 [xfs_io]
253,0 21 7 0.000035130 2206 X R 736 / 768 [xfs_io]
253,0 21 8 0.000039146 2206 X R 992 / 1248 [xfs_io]
253,0 21 9 0.000040734 2206 X R 992 / 1024 [xfs_io]
253,0 21 10 0.000044694 2206 X R 1248 / 1504 [xfs_io]
253,0 21 11 0.000046422 2206 X R 1248 / 1280 [xfs_io]
253,0 21 12 0.000050376 2206 X R 1504 / 1760 [xfs_io]
253,0 21 13 0.000051974 2206 X R 1504 / 1536 [xfs_io]
253,0 21 14 0.000055881 2206 X R 1760 / 2016 [xfs_io]
253,0 21 15 0.000057462 2206 X R 1760 / 1792 [xfs_io]
253,0 21 16 0.000060999 2206 X R 2016 / 2272 [xfs_io]
253,0 21 17 0.000062489 2206 X R 2016 / 2048 [xfs_io]
253,0 21 18 0.000066133 2206 X R 2272 / 2528 [xfs_io]
253,0 21 19 0.000067507 2206 X R 2272 / 2304 [xfs_io]
253,0 21 20 0.000071136 2206 X R 2528 / 2784 [xfs_io]
253,0 21 21 0.000072764 2206 X R 2528 / 2560 [xfs_io]
253,0 21 22 0.000076185 2206 X R 2784 / 3040 [xfs_io]
253,0 21 23 0.000077486 2206 X R 2784 / 2816 [xfs_io]
253,0 21 24 0.000080885 2206 X R 3040 / 3296 [xfs_io]
253,0 21 25 0.000082316 2206 X R 3040 / 3072 [xfs_io]
253,0 21 26 0.000085788 2206 X R 3296 / 3552 [xfs_io]
253,0 21 27 0.000087096 2206 X R 3296 / 3328 [xfs_io]
253,0 21 28 0.000093469 2206 X R 3552 / 3808 [xfs_io]
253,0 21 29 0.000095186 2206 X R 3552 / 3584 [xfs_io]
253,0 21 30 0.000099228 2206 X R 3808 / 4064 [xfs_io]
253,0 21 31 0.000101062 2206 X R 3808 / 3840 [xfs_io]
253,0 21 32 0.000104956 2206 X R 4064 / 4096 [xfs_io]
253,0 21 33 0.001138823 0 C R 4096 + 200 [0]
after this revert:
253,0 18 1 0.000000000 4430 Q R 224 + 3896 [xfs_io]
253,0 18 2 0.000018359 4430 X R 224 / 256 [xfs_io]
253,0 18 3 0.000028898 4430 X R 256 / 512 [xfs_io]
253,0 18 4 0.000033535 4430 X R 512 / 768 [xfs_io]
253,0 18 5 0.000065684 4430 X R 768 / 1024 [xfs_io]
253,0 18 6 0.000091695 4430 X R 1024 / 1280 [xfs_io]
253,0 18 7 0.000098494 4430 X R 1280 / 1536 [xfs_io]
253,0 18 8 0.000114069 4430 X R 1536 / 1792 [xfs_io]
253,0 18 9 0.000129483 4430 X R 1792 / 2048 [xfs_io]
253,0 18 10 0.000136759 4430 X R 2048 / 2304 [xfs_io]
253,0 18 11 0.000152412 4430 X R 2304 / 2560 [xfs_io]
253,0 18 12 0.000160758 4430 X R 2560 / 2816 [xfs_io]
253,0 18 13 0.000183385 4430 X R 2816 / 3072 [xfs_io]
253,0 18 14 0.000190797 4430 X R 3072 / 3328 [xfs_io]
253,0 18 15 0.000197667 4430 X R 3328 / 3584 [xfs_io]
253,0 18 16 0.000218751 4430 X R 3584 / 3840 [xfs_io]
253,0 18 17 0.000226005 4430 X R 3840 / 4096 [xfs_io]
253,0 18 18 0.000250404 4430 Q R 4120 + 176 [xfs_io]
253,0 18 19 0.000847708 0 C R 4096 + 24 [0]
253,0 18 20 0.000855783 0 C R 4120 + 176 [0]
Fixes: effd58c95f ("dm: always call blk_queue_split() in dm_process_bio()")
Cc: stable@vger.kernel.org
Reported-by: Andreas Gruenbacher <agruenba@redhat.com>
Tested-by: Barry Marson <bmarson@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 248aa2645a ]
In cases where dec_in_flight() has to requeue the integrity_bio_wait
work to transfer the rest of the data, the bio's __bi_remaining might
already have been decremented to 0, e.g.: if bio passed to underlying
data device was split via blk_queue_split().
Use dm_bio_{record,restore} rather than effectively open-coding them in
dm-integrity -- these methods now manage __bi_remaining too.
Depends-on: f7f0b057a9c1 ("dm bio record: save/restore bi_end_io and bi_integrity")
Reported-by: Daniel Glöckner <dg@emlix.com>
Suggested-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1b17159e52 ]
Also, save/restore __bi_remaining in case the bio was used in a
BIO_CHAIN (e.g. due to blk_queue_split).
Suggested-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 974f51e863 upstream.
We neither assign congested_fn for requested-based blk-mq device nor
implement it correctly. So fix both.
Also, remove incorrect comment from dm_init_normal_md_queue and rename
it to dm_init_congested_fn.
Fixes: 4aa9c692e0 ("bdi: separate out congested state into a separate struct")
Cc: stable@vger.kernel.org
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ee63634bae upstream.
Dm-zoned initializes reference counters of new chunk works with zero
value and refcount_inc() is called to increment the counter. However, the
refcount_inc() function handles the addition to zero value as an error
and triggers the warning as follows:
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 7 PID: 1506 at lib/refcount.c:25 refcount_warn_saturate+0x68/0xf0
...
CPU: 7 PID: 1506 Comm: systemd-udevd Not tainted 5.4.0+ #134
...
Call Trace:
dmz_map+0x2d2/0x350 [dm_zoned]
__map_bio+0x42/0x1a0
__split_and_process_non_flush+0x14a/0x1b0
__split_and_process_bio+0x83/0x240
? kmem_cache_alloc+0x165/0x220
dm_process_bio+0x90/0x230
? generic_make_request_checks+0x2e7/0x680
dm_make_request+0x3e/0xb0
generic_make_request+0xcf/0x320
? memcg_drain_all_list_lrus+0x1c0/0x1c0
submit_bio+0x3c/0x160
? guard_bio_eod+0x2c/0x130
mpage_readpages+0x182/0x1d0
? bdev_evict_inode+0xf0/0xf0
read_pages+0x6b/0x1b0
__do_page_cache_readahead+0x1ba/0x1d0
force_page_cache_readahead+0x93/0x100
generic_file_read_iter+0x83a/0xe40
? __seccomp_filter+0x7b/0x670
new_sync_read+0x12a/0x1c0
vfs_read+0x9d/0x150
ksys_read+0x5f/0xe0
do_syscall_64+0x5b/0x180
entry_SYSCALL_64_after_hwframe+0x44/0xa9
...
After this warning, following refcount API calls for the counter all fail
to change the counter value.
Fix this by setting the initial reference counter value not zero but one
for the new chunk works. Instead, do not call refcount_inc() via
dmz_get_chunk_work() for the new chunks works.
The failure was observed with linux version 5.4 with CONFIG_REFCOUNT_FULL
enabled. Refcount rework was merged to linux version 5.5 by the
commit 168829ad09 ("Merge branch 'locking-core-for-linus' of
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip"). After this
commit, CONFIG_REFCOUNT_FULL was removed and the failure was observed
regardless of kernel configuration.
Linux version 4.20 merged the commit 092b564876 ("dm zoned: target: use
refcount_t for dm zoned reference counters"). Before this commit, dm
zoned used atomic_t APIs which does not check addition to zero, then this
fix is not necessary.
Fixes: 092b564876 ("dm zoned: target: use refcount_t for dm zoned reference counters")
Cc: stable@vger.kernel.org # 5.4+
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 41c526c5af upstream.
Verify the watermark upon resume - so that if the target is reloaded
with lower watermark, it will start the cleanup process immediately.
Fixes: 48debafe4f ("dm: add writecache target")
Cc: stable@vger.kernel.org # 4.18+
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit adc0daad36 upstream.
The function dm_suspended returns true if the target is suspended.
However, when the target is being suspended during unload, it returns
false.
An example where this is a problem: the test "!dm_suspended(wc->ti)" in
writecache_writeback is not sufficient, because dm_suspended returns
zero while writecache_suspend is in progress. As is, without an
enhanced dm_suspended, simply switching from flush_workqueue to
drain_workqueue still emits warnings:
workqueue writecache-writeback: drain_workqueue() isn't complete after 10 tries
workqueue writecache-writeback: drain_workqueue() isn't complete after 100 tries
workqueue writecache-writeback: drain_workqueue() isn't complete after 200 tries
workqueue writecache-writeback: drain_workqueue() isn't complete after 300 tries
workqueue writecache-writeback: drain_workqueue() isn't complete after 400 tries
writecache_suspend calls flush_workqueue(wc->writeback_wq) - this function
flushes the current work. However, the workqueue may re-queue itself and
flush_workqueue doesn't wait for re-queued works to finish. Because of
this - the function writecache_writeback continues execution after the
device was suspended and then concurrently with writecache_dtr, causing
a crash in writecache_writeback.
We must use drain_workqueue - that waits until the work and all re-queued
works finish.
As a prereq for switching to drain_workqueue, this commit fixes
dm_suspended to return true after the presuspend hook and before the
postsuspend hook - just like during a normal suspend. It allows
simplifying the dm-integrity and dm-writecache targets so that they
don't have to maintain suspended flags on their own.
With this change use of drain_workqueue() can be used effectively. This
change was tested with the lvm2 testsuite and cryptsetup testsuite and
the are no regressions.
Fixes: 48debafe4f ("dm: add writecache target")
Cc: stable@vger.kernel.org # 4.18+
Reported-by: Corey Marthaler <cmarthal@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7cdf6a0aae upstream.
The crash can be reproduced by running the lvm2 testsuite test
lvconvert-thin-external-cache.sh for several minutes, e.g.:
while :; do make check T=shell/lvconvert-thin-external-cache.sh; done
The crash happens in this call chain:
do_waker -> policy_tick -> smq_tick -> end_hotspot_period -> clear_bitset
-> memset -> __memset -- which accesses an invalid pointer in the vmalloc
area.
The work entry on the workqueue is executed even after the bitmap was
freed. The problem is that cancel_delayed_work doesn't wait for the
running work item to finish, so the work item can continue running and
re-submitting itself even after cache_postsuspend. In order to make sure
that the work item won't be running, we must use cancel_delayed_work_sync.
Also, change flush_workqueue to drain_workqueue, so that if some work item
submits itself or another work item, we are properly waiting for both of
them.
Fixes: c6b4fcbad0 ("dm: add cache target")
Cc: stable@vger.kernel.org # v3.9
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7fc2e47f40 upstream.
If the flag SB_FLAG_RECALCULATE is present in the superblock, but it was
not specified on the command line (i.e. ic->recalculate_flag is false),
dm-integrity would return invalid table line - the reported number of
arguments would not match the real number.
Fixes: 468dfca38b ("dm integrity: add a bitmap mode")
Cc: stable@vger.kernel.org # v5.2+
Reported-by: Ondrej Kozina <okozina@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 53770f0ec5 upstream.
If we need to perform synchronous I/O in dm_integrity_map_continue(),
we must make sure that we are not in the map function - in order to
avoid the deadlock due to bio queuing in generic_make_request. To
avoid the deadlock, we offload the request to metadata_wq.
However, metadata_wq also processes metadata updates for write requests.
If there are too many requests that get offloaded to metadata_wq at the
beginning of dm_integrity_map_continue, the workqueue metadata_wq
becomes clogged and the system is incapable of processing any metadata
updates.
This causes a deadlock because all the requests that need to do metadata
updates wait for metadata_wq to proceed and metadata_wq waits inside
wait_and_add_new_range until some existing request releases its range
lock (which doesn't happen because the range lock is released after
metadata update).
In order to fix the deadlock, we create a new workqueue offload_wq and
offload requests to it - so that processing of offload_wq is independent
from processing of metadata_wq.
Fixes: 7eada909bf ("dm: add integrity target")
Cc: stable@vger.kernel.org # v4.12+
Reported-by: Heinz Mauelshagen <heinzm@redhat.com>
Tested-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d5bdf66108 upstream.
If we resume a device in bitmap mode and the on-disk format is in journal
mode, we must recalculate anything above ic->sb->recalc_sector. Otherwise,
there would be non-recalculated blocks which would cause I/O errors.
Fixes: 468dfca38b ("dm integrity: add a bitmap mode")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 3918e0667b ]
[ 3934.173244] ======================================================
[ 3934.179572] WARNING: possible circular locking dependency detected
[ 3934.185884] 5.4.21-xfstests #1 Not tainted
[ 3934.190151] ------------------------------------------------------
[ 3934.196673] dmsetup/8897 is trying to acquire lock:
[ 3934.201688] ffffffffbce82b18 (shrinker_rwsem){++++}, at: unregister_shrinker+0x22/0x80
[ 3934.210268]
but task is already holding lock:
[ 3934.216489] ffff92a10cc5e1d0 (&pmd->root_lock){++++}, at: dm_pool_metadata_close+0xba/0x120
[ 3934.225083]
which lock already depends on the new lock.
[ 3934.564165] Chain exists of:
shrinker_rwsem --> &journal->j_checkpoint_mutex --> &pmd->root_lock
For a more detailed lockdep report, please see:
https://lore.kernel.org/r/20200220234519.GA620489@mit.edu
We shouldn't need to hold the lock while are just tearing down and
freeing the whole metadata pool structure.
Fixes: 44d8ebf436 ("dm thin metadata: use pool locking at end of dm_pool_metadata_close")
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 29cda393bc ]
Patch "bcache: rework error unwinding in register_bcache" from
Christoph Hellwig changes the local variables 'path' and 'err'
in undefined initial state. If the code in register_bcache() jumps
to label 'out:' or 'out_module_put:' by goto, these two variables
might be reference with undefined value by the following line,
out_module_put:
module_put(THIS_MODULE);
out:
pr_info("error %s: %s", path, err);
return ret;
Therefore this patch initializes these two local variables properly
in register_bcache() to avoid such issue.
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d1c3cc34f5 ]
Dan Carpenter points out that from commit 2aa8c52938 ("bcache: avoid
unnecessary btree nodes flushing in btree_flush_write()"), there is a
incorrect data type usage which leads to the following static checker
warning:
drivers/md/bcache/journal.c:444 btree_flush_write()
warn: 'ref_nr' unsigned <= 0
drivers/md/bcache/journal.c
422 static void btree_flush_write(struct cache_set *c)
423 {
424 struct btree *b, *t, *btree_nodes[BTREE_FLUSH_NR];
425 unsigned int i, nr, ref_nr;
^^^^^^
426 atomic_t *fifo_front_p, *now_fifo_front_p;
427 size_t mask;
428
429 if (c->journal.btree_flushing)
430 return;
431
432 spin_lock(&c->journal.flush_write_lock);
433 if (c->journal.btree_flushing) {
434 spin_unlock(&c->journal.flush_write_lock);
435 return;
436 }
437 c->journal.btree_flushing = true;
438 spin_unlock(&c->journal.flush_write_lock);
439
440 /* get the oldest journal entry and check its refcount */
441 spin_lock(&c->journal.lock);
442 fifo_front_p = &fifo_front(&c->journal.pin);
443 ref_nr = atomic_read(fifo_front_p);
444 if (ref_nr <= 0) {
^^^^^^^^^^^
Unsigned can't be less than zero.
445 /*
446 * do nothing if no btree node references
447 * the oldest journal entry
448 */
449 spin_unlock(&c->journal.lock);
450 goto out;
451 }
452 spin_unlock(&c->journal.lock);
As the warning information indicates, local varaible ref_nr in unsigned
int type is wrong, which does not matche atomic_read() and the "<= 0"
checking.
This patch fixes the above error by defining local variable ref_nr as
int type.
Fixes: 2aa8c52938 ("bcache: avoid unnecessary btree nodes flushing in btree_flush_write()")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Coly Li