linux-stable.git/drivers/md, branch v5.2.4

dm bufio: fix deadlock with loop device

2019-07-26T07:11:11+00:00

commit bd293d071ffe65e645b4d8104f9d8fe15ea13862 upstream.

When thin-volume is built on loop device, if available memory is low,
the following deadlock can be triggered:

One process P1 allocates memory with GFP_FS flag, direct alloc fails,
memory reclaim invokes memory shrinker in dm_bufio, dm_bufio_shrink_scan()
runs, mutex dm_bufio_client->lock is acquired, then P1 waits for dm_buffer
IO to complete in __try_evict_buffer().

But this IO may never complete if issued to an underlying loop device
that forwards it using direct-IO, which allocates memory using
GFP_KERNEL (see: do_blockdev_direct_IO()).  If allocation fails, memory
reclaim will invoke memory shrinker in dm_bufio, dm_bufio_shrink_scan()
will be invoked, and since the mutex is already held by P1 the loop
thread will hang, and IO will never complete.  Resulting in ABBA
deadlock.

Cc: stable@vger.kernel.org
Signed-off-by: Junxiao Bi 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm thin metadata: check if in fail_io mode when setting needs_check

2019-07-26T07:11:11+00:00

commit 54fa16ee532705985e6c946da455856f18f63ee1 upstream.

Check if in fail_io mode at start of dm_pool_metadata_set_needs_check().
Otherwise dm_pool_metadata_set_needs_check()'s superblock_lock() can
crash in dm_bm_write_lock() while accessing the block manager object
that was previously destroyed as part of a failed
dm_pool_abort_metadata() that ultimately set fail_io to begin with.

Also, update DMERR() message to more accurately describe
superblock_lock() failure.

Cc: stable@vger.kernel.org
Reported-by: Zdenek Kabelac 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm zoned: fix zone state management race

2019-07-26T07:11:02+00:00

commit 3b8cafdd5436f9298b3bf6eb831df5eef5ee82b6 upstream.

dm-zoned uses the zone flag DMZ_ACTIVE to indicate that a zone of the
backend device is being actively read or written and so cannot be
reclaimed. This flag is set as long as the zone atomic reference
counter is not 0. When this atomic is decremented and reaches 0 (e.g.
on BIO completion), the active flag is cleared and set again whenever
the zone is reused and BIO issued with the atomic counter incremented.
These 2 operations (atomic inc/dec and flag set/clear) are however not
always executed atomically under the target metadata mutex lock and
this causes the warning:

WARN_ON(!test_bit(DMZ_ACTIVE, &zone->flags));

in dmz_deactivate_zone() to be displayed. This problem is regularly
triggered with xfstests generic/209, generic/300, generic/451 and
xfs/077 with XFS being used as the file system on the dm-zoned target
device. Similarly, xfstests ext4/303, ext4/304, generic/209 and
generic/300 trigger the warning with ext4 use.

This problem can be easily fixed by simply removing the DMZ_ACTIVE flag
and managing the "ACTIVE" state by directly looking at the reference
counter value. To do so, the functions dmz_activate_zone() and
dmz_deactivate_zone() are changed to inline functions respectively
calling atomic_inc() and atomic_dec(), while the dmz_is_active() macro
is changed to an inline function calling atomic_read().

Fixes: 3b1a94c88b79 ("dm zoned: drive-managed zoned block device target")
Cc: stable@vger.kernel.org
Reported-by: Masato Suzuki 
Signed-off-by: Damien Le Moal 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

raid5-cache: Need to do start() part job after adding journal device

2019-07-26T07:10:56+00:00

commit d9771f5ec46c282d518b453c793635dbdc3a2a94 upstream.

commit d5d885fd514f ("md: introduce new personality funciton start()")
splits the init job to two parts. The first part run() does the jobs that
do not require the md threads. The second part start() does the jobs that
require the md threads.

Now it just does run() in adding new journal device. It needs to do the
second part start() too.

Fixes: d5d885fd514f ("md: introduce new personality funciton start()")
Cc: stable@vger.kernel.org #v4.9+
Reported-by: Michal Soltys 
Signed-off-by: Xiao Ni 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: destroy dc->writeback_write_wq if failed to create dc->writeback_thread

2019-07-26T07:10:52+00:00

commit f54d801dda14942dbefa00541d10603015b7859c upstream.

Commit 9baf30972b55 ("bcache: fix for gc and write-back race") added a
new work queue dc->writeback_write_wq, but forgot to destroy it in the
error condition when creating dc->writeback_thread failed.

This patch destroys dc->writeback_write_wq if kthread_create() returns
error pointer to dc->writeback_thread, then a memory leak is avoided.

Fixes: 9baf30972b55 ("bcache: fix for gc and write-back race")
Signed-off-by: Coly Li 
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: fix mistaken sysfs entry for io_error counter

2019-07-26T07:10:52+00:00

commit 5461999848e0462c14f306a62923d22de820a59c upstream.

In bch_cached_dev_files[] from driver/md/bcache/sysfs.c, sysfs_errors is
incorrectly inserted in. The correct entry should be sysfs_io_errors.

This patch fixes the problem and now I/O errors of cached device can be
read from /sys/block/bcache/bcache/io_errors.

Fixes: c7b7bd07404c5 ("bcache: add io_disable to struct cached_dev")
Signed-off-by: Coly Li 
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: ignore read-ahead request failure on backing device

2019-07-26T07:10:52+00:00

commit 578df99b1b0531d19af956530fe4da63d01a1604 upstream.

When md raid device (e.g. raid456) is used as backing device, read-ahead
requests on a degrading and recovering md raid device might be failured
immediately by md raid code, but indeed this md raid array can still be
read or write for normal I/O requests. Therefore such failed read-ahead
request are not real hardware failure. Further more, after degrading and
recovering accomplished, read-ahead requests will be handled by md raid
array again.

For such condition, I/O failures of read-ahead requests don't indicate
real health status (because normal I/O still be served), they should not
be counted into I/O error counter dc->io_errors.

Since there is no simple way to detect whether the backing divice is a
md raid device, this patch simply ignores I/O failures for read-ahead
bios on backing device, to avoid bogus backing device failure on a
degrading md raid array.

Suggested-and-tested-by: Thorsten Knabe 
Signed-off-by: Coly Li 
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: Revert "bcache: free heap cache_set->flush_btree in bch_journal_free"

2019-07-26T07:10:52+00:00

commit ba82c1ac1667d6efb91a268edb13fc9cdaecec9b upstream.

This reverts commit 6268dc2c4703aabfb0b35681be709acf4c2826c6.

This patch depends on commit c4dc2497d50d ("bcache: fix high CPU
occupancy during journal") which is reverted in previous patch. So
revert this one too.

Fixes: 6268dc2c4703 ("bcache: free heap cache_set->flush_btree in bch_journal_free")
Signed-off-by: Coly Li 
Cc: stable@vger.kernel.org
Cc: Shenghui Wang 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: Revert "bcache: fix high CPU occupancy during journal"

2019-07-26T07:10:52+00:00

commit 249a5f6da57c28a903c75d81505d58ec8c10030d upstream.

This reverts commit c4dc2497d50d9c6fb16aa0d07b6a14f3b2adb1e0.

This patch enlarges a race between normal btree flush code path and
flush_btree_write(), which causes deadlock when journal space is
exhausted. Reverts this patch makes the race window from 128 btree
nodes to only 1 btree nodes.

Fixes: c4dc2497d50d ("bcache: fix high CPU occupancy during journal")
Signed-off-by: Coly Li 
Cc: stable@vger.kernel.org
Cc: Tang Junhui 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

Revert "bcache: set CACHE_SET_IO_DISABLE in bch_cached_dev_error()"

2019-07-26T07:10:51+00:00

commit 695277f16b3a102fcc22c97fdf2de77c7b19f0b3 upstream.

This reverts commit 6147305c73e4511ca1a975b766b97a779d442567.

Although this patch helps the failed bcache device to stop faster when
too many I/O errors detected on corresponding cached device, setting
CACHE_SET_IO_DISABLE bit to cache set c->flags was not a good idea. This
operation will disable all I/Os on cache set, which means other attached
bcache devices won't work neither.

Without this patch, the failed bcache device can also be stopped
eventually if internal I/O accomplished (e.g. writeback). Therefore here
I revert it.

Fixes: 6147305c73e4 ("bcache: set CACHE_SET_IO_DISABLE in bch_cached_dev_error()")
Reported-by: Yong Li 
Signed-off-by: Coly Li 
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman