linux-stable.git/drivers/md/bcache, branch v5.2.1

bcache: only set BCACHE_DEV_WB_RUNNING when cached device attached

2019-06-13T09:09:15+00:00

When people set a writeback percent via sysfs file,
  /sys/block/bcache/bcache/writeback_percent
current code directly sets BCACHE_DEV_WB_RUNNING to dc->disk.flags
and schedules kworker dc->writeback_rate_update.

If there is no cache set attached to, the writeback kernel thread is
not running indeed, running dc->writeback_rate_update does not make
sense and may cause NULL pointer deference when reference cache set
pointer inside update_writeback_rate().

This patch checks whether the cache set point (dc->disk.c) is NULL in
sysfs interface handler, and only set BCACHE_DEV_WB_RUNNING and
schedule dc->writeback_rate_update when dc->disk.c is not NULL (it
means the cache device is attached to a cache set).

This problem might be introduced from initial bcache commit, but
commit 3fd47bfe55b0 ("bcache: stop dc->writeback_rate_update properly")
changes part of the original code piece, so I add 'Fixes: 3fd47bfe55b0'
to indicate from which commit this patch can be applied.

Fixes: 3fd47bfe55b0 ("bcache: stop dc->writeback_rate_update properly")
Reported-by: Bjørn Forsman 
Signed-off-by: Coly Li 
Reviewed-by: Bjørn Forsman 
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe

bcache: fix stack corruption by PRECEDING_KEY()

2019-06-13T09:09:14+00:00

Recently people report bcache code compiled with gcc9 is broken, one of
the buggy behavior I observe is that two adjacent 4KB I/Os should merge
into one but they don't. Finally it turns out to be a stack corruption
caused by macro PRECEDING_KEY().

See how PRECEDING_KEY() is defined in bset.h,
437 #define PRECEDING_KEY(_k)                                       \
438 ({                                                              \
439         struct bkey *_ret = NULL;                               \
440                                                                 \
441         if (KEY_INODE(_k) || KEY_OFFSET(_k)) {                  \
442                 _ret = &KEY(KEY_INODE(_k), KEY_OFFSET(_k), 0);  \
443                                                                 \
444                 if (!_ret->low)                                 \
445                         _ret->high--;                           \
446                 _ret->low--;                                    \
447         }                                                       \
448                                                                 \
449         _ret;                                                   \
450 })

At line 442, _ret points to address of a on-stack variable combined by
KEY(), the life range of this on-stack variable is in line 442-446,
once _ret is returned to bch_btree_insert_key(), the returned address
points to an invalid stack address and this address is overwritten in
the following called bch_btree_iter_init(). Then argument 'search' of
bch_btree_iter_init() points to some address inside stackframe of
bch_btree_iter_init(), exact address depends on how the compiler
allocates stack space. Now the stack is corrupted.

Fixes: 0eacac22034c ("bcache: PRECEDING_KEY()")
Signed-off-by: Coly Li 
Reviewed-by: Rolf Fokkens 
Reviewed-by: Pierre JUHEN 
Tested-by: Shenghui Wang 
Tested-by: Pierre JUHEN 
Cc: Kent Overstreet 
Cc: Nix 
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46+00:00

Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

bcache: make is_discard_enabled() static

2019-05-01T12:34:09+00:00

It's not used outside this file.

Fixes: 631207314d88 ("bcache: fix failure in journal relplay")
Signed-off-by: Jens Axboe

block: remove the i argument to bio_for_each_segment_all

2019-04-30T15:26:13+00:00

We only have two callers that need the integer loop iterator, and they
can easily maintain it themselves.

Suggested-by: Matthew Wilcox 
Reviewed-by: Johannes Thumshirn 
Acked-by: David Sterba 
Reviewed-by: Hannes Reinecke 
Acked-by: Coly Li 
Reviewed-by: Matthew Wilcox 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

bcache: clean up do_btree_node_write a bit

2019-04-30T15:26:11+00:00

Use a variable containing the buffer address instead of the to be
removed integer iterator from bio_for_each_segment_all.

Suggested-by: Matthew Wilcox 
Reviewed-by: Hannes Reinecke 
Acked-by: Coly Li 
Reviewed-by: Matthew Wilcox 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

bcache: remove redundant LIST_HEAD(journal) from run_cache_set()

2019-04-30T14:20:46+00:00

Commit 95f18c9d1310 ("bcache: avoid potential memleak of list of
journal_replay(s) in the CACHE_SYNC branch of run_cache_set") forgets
to remove the original define of LIST_HEAD(journal), which makes
the change no take effect. This patch removes redundant variable
LIST_HEAD(journal) from run_cache_set(), to make Shenghui's fix
working.

Fixes: 95f18c9d1310 ("bcache: avoid potential memleak of list of journal_replay(s) in the CACHE_SYNC branch of run_cache_set")
Reported-by: Juha Aatrokoski 
Cc: Shenghui Wang 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: avoid potential memleak of list of journal_replay(s) in the CACHE_SYNC branch of run_cache_set

2019-04-24T16:56:29+00:00

In the CACHE_SYNC branch of run_cache_set(), LIST_HEAD(journal) is used
to collect journal_replay(s) and filled by bch_journal_read().

If all goes well, bch_journal_replay() will release the list of
jounal_replay(s) at the end of the branch.

If something goes wrong, code flow will jump to the label "err:" and leave
the list unreleased.

This patch will release the list of journal_replay(s) in the case of
error detected.

v1 -> v2:
* Move the release code to the location after label 'err:' to
  simply the change.

Signed-off-by: Shenghui Wang 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: fix wrong usage use-after-freed on keylist in out_nocoalesce branch of btree_gc_coalesce

2019-04-24T16:56:29+00:00

Elements of keylist should be accessed before the list is freed.
Move bch_keylist_free() calling after the while loop to avoid wrong
content accessed.

Signed-off-by: Shenghui Wang 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: fix failure in journal relplay

2019-04-24T16:56:28+00:00

journal replay failed with messages:
Sep 10 19:10:43 ceph kernel: bcache: error on
bb379a64-e44e-4812-b91d-a5599871a3b1: bcache: journal entries
2057493-2057567 missing! (replaying 2057493-2076601), disabling
caching

The reason is in journal_reclaim(), when discard is enabled, we send
discard command and reclaim those journal buckets whose seq is old
than the last_seq_now, but before we write a journal with last_seq_now,
the machine is restarted, so the journal with the last_seq_now is not
written to the journal bucket, and the last_seq_wrote in the newest
journal is old than last_seq_now which we expect to be, so when we doing
replay, journals from last_seq_wrote to last_seq_now are missing.

It's hard to write a journal immediately after journal_reclaim(),
and it harmless if those missed journal are caused by discarding
since those journals are already wrote to btree node. So, if miss
seqs are started from the beginning journal, we treat it as normal,
and only print a message to show the miss journal, and point out
it maybe caused by discarding.

Patch v2 add a judgement condition to ignore the missed journal
only when discard enabled as Coly suggested.

(Coly Li: rebase the patch with other changes in bch_journal_replay())

Signed-off-by: Tang Junhui 
Tested-by: Dennis Schridde 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe