linux-stable.git/drivers/md/bcache/sysfs.c, branch v5.3

bcache: Revert "bcache: use sysfs_match_string() instead of __sysfs_match_string()"

2019-08-09T13:37:33+00:00

This reverts commit 89e0341af082dbc170019f908846f4a424efc86b.

In drivers/md/bcache/sysfs.c:bch_snprint_string_list(), NULL pointer at
the end of list is necessary. Remove the NULL from last element of each
lists will cause the following panic,

[ 4340.455652] bcache: register_cache() registered cache device nvme0n1
[ 4340.464603] bcache: register_bdev() registered backing device sdk
[ 4421.587335] bcache: bch_cached_dev_run() cached dev sdk is running already
[ 4421.587348] bcache: bch_cached_dev_attach() Caching sdk as bcache0 on set 354e1d46-d99f-4d8b-870b-078b80dc88a6
[ 5139.247950] general protection fault: 0000 [#1] SMP NOPTI
[ 5139.247970] CPU: 9 PID: 5896 Comm: cat Not tainted 4.12.14-95.29-default #1 SLE12-SP4
[ 5139.247988] Hardware name: HPE ProLiant DL380 Gen10/ProLiant DL380 Gen10, BIOS U30 04/18/2019
[ 5139.248006] task: ffff888fb25c0b00 task.stack: ffff9bbacc704000
[ 5139.248021] RIP: 0010:string+0x21/0x70
[ 5139.248030] RSP: 0018:ffff9bbacc707bf0 EFLAGS: 00010286
[ 5139.248043] RAX: ffffffffa7e432e3 RBX: ffff8881c20da02a RCX: ffff0a00ffffff04
[ 5139.248058] RDX: 3f00656863616362 RSI: ffff8881c20db000 RDI: ffffffffffffffff
[ 5139.248075] RBP: ffff8881c20db000 R08: 0000000000000000 R09: ffff8881c20da02a
[ 5139.248090] R10: 0000000000000004 R11: 0000000000000000 R12: ffff9bbacc707c48
[ 5139.248104] R13: 0000000000000fd6 R14: ffffffffc0665855 R15: ffffffffc0665855
[ 5139.248119] FS:  00007faf253b8700(0000) GS:ffff88903f840000(0000) knlGS:0000000000000000
[ 5139.248137] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 5139.248149] CR2: 00007faf25395008 CR3: 0000000f72150006 CR4: 00000000007606e0
[ 5139.248164] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 5139.248179] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 5139.248193] PKRU: 55555554
[ 5139.248200] Call Trace:
[ 5139.248210]  vsnprintf+0x1fb/0x510
[ 5139.248221]  snprintf+0x39/0x40
[ 5139.248238]  bch_snprint_string_list.constprop.15+0x5b/0x90 [bcache]
[ 5139.248256]  __bch_cached_dev_show+0x44d/0x5f0 [bcache]
[ 5139.248270]  ? __alloc_pages_nodemask+0xb2/0x210
[ 5139.248284]  bch_cached_dev_show+0x2c/0x50 [bcache]
[ 5139.248297]  sysfs_kf_seq_show+0xbb/0x190
[ 5139.248308]  seq_read+0xfc/0x3c0
[ 5139.248317]  __vfs_read+0x26/0x140
[ 5139.248327]  vfs_read+0x87/0x130
[ 5139.248336]  SyS_read+0x42/0x90
[ 5139.248346]  do_syscall_64+0x74/0x160
[ 5139.248358]  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 5139.248370] RIP: 0033:0x7faf24eea370
[ 5139.248379] RSP: 002b:00007fff82d03f38 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 5139.248395] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007faf24eea370
[ 5139.248411] RDX: 0000000000020000 RSI: 00007faf25396000 RDI: 0000000000000003
[ 5139.248426] RBP: 00007faf25396000 R08: 00000000ffffffff R09: 0000000000000000
[ 5139.248441] R10: 000000007c9d4d41 R11: 0000000000000246 R12: 00007faf25396000
[ 5139.248456] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff
[ 5139.248892] Code: ff ff ff 0f 1f 80 00 00 00 00 49 89 f9 48 89 cf 48 c7 c0 e3 32 e4 a7 48 c1 ff 30 48 81 fa ff 0f 00 00 48 0f 46 d0 48 85 ff 74 45 <44> 0f b6 02 48 8d 42 01 45 84 c0 74 38 48 01 fa 4c 89 cf eb 0e

The simplest way to fix is to revert commit 89e0341af082 ("bcache: use
sysfs_match_string() instead of __sysfs_match_string()").

This bug was introduced in Linux v5.2, so this fix only applies to
Linux v5.2 is enough for stable tree maintainer.

Fixes: 89e0341af082 ("bcache: use sysfs_match_string() instead of __sysfs_match_string()")
Cc: stable@vger.kernel.org
Cc: Alexandru Ardelean 
Reported-by: Peifeng Lin 
Acked-by: Alexandru Ardelean 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: add reclaimed_journal_buckets to struct cache_set

2019-06-28T13:39:18+00:00

Now we have counters for how many times jouranl is reclaimed, how many
times cached dirty btree nodes are flushed, but we don't know how many
jouranl buckets are really reclaimed.

This patch adds reclaimed_journal_buckets into struct cache_set, this
is an increasing only counter, to tell how many journal buckets are
reclaimed since cache set runs. From all these three counters (reclaim,
reclaimed_journal_buckets, flush_write), we can have idea how well
current journal space reclaim code works.

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

bcache: remove retry_flush_write from struct cache_set

2019-06-28T13:39:18+00:00

In struct cache_set, retry_flush_write is added for commit c4dc2497d50d
("bcache: fix high CPU occupancy during journal") which is reverted in
previous patch.

Now it is useless anymore, and this patch removes it from bcache code.

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

bcache: avoid a deadlock in bcache_reboot()

2019-06-28T13:39:16+00:00

It is quite frequently to observe deadlock in bcache_reboot() happens
and hang the system reboot process. The reason is, in bcache_reboot()
when calling bch_cache_set_stop() and bcache_device_stop() the mutex
bch_register_lock is held. But in the process to stop cache set and
bcache device, bch_register_lock will be acquired again. If this mutex
is held here, deadlock will happen inside the stopping process. The
aftermath of the deadlock is, whole system reboot gets hung.

The fix is to avoid holding bch_register_lock for the following loops
in bcache_reboot(),
       list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
                bch_cache_set_stop(c);

        list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
                bcache_device_stop(&dc->disk);

A module range variable 'bcache_is_reboot' is added, it sets to true
in bcache_reboot(). In register_bcache(), if bcache_is_reboot is checked
to be true, reject the registration by returning -EBUSY immediately.

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

bcache: fix mistaken sysfs entry for io_error counter

2019-06-28T13:39:16+00:00

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

bcache: add return value check to bch_cached_dev_run()

2019-06-28T13:39:14+00:00

This patch adds return value check to bch_cached_dev_run(), now if there
is error happens inside bch_cached_dev_run(), it can be catched.

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

bcache: use sysfs_match_string() instead of __sysfs_match_string()

2019-06-28T13:39:14+00:00

The arrays (of strings) that are passed to __sysfs_match_string() are
static, so use sysfs_match_string() which does an implicit ARRAY_SIZE()
over these arrays.

Functionally, this doesn't change anything.
The change is more cosmetic.

It only shrinks the static arrays by 1 byte each.

Signed-off-by: Alexandru Ardelean 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

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 inaccurate result of unused buckets

2019-04-24T16:56:27+00:00

To get the amount of unused buckets in sysfs_priority_stats, the code
count the buckets which GC_SECTORS_USED is zero. It's correct and should
not be overwritten by the count of buckets which prio is zero.

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

bcache: fix input overflow to cache set sysfs file io_error_halflife

2019-02-09T14:18:33+00:00

Cache set sysfs entry io_error_halflife is used to set c->error_decay.
c->error_decay is in type unsigned int, and it is converted by
strtoul_or_return(), therefore overflow to c->error_decay is possible
for a large input value.

This patch fixes the overflow by using strtoul_safe_clamp() to convert
input string to an unsigned long value in range [0, UINT_MAX], then
divides by 88 and set it to c->error_decay.

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