Commit Graph

564 Commits

Author SHA1 Message Date
Christoph Hellwig 2b070cfe58 block: remove the i argument to bio_for_each_segment_all
We only have two callers that need the integer loop iterator, and they
can easily maintain it themselves.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: David Sterba <dsterba@suse.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Acked-by: Coly Li <colyli@suse.de>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-30 09:26:13 -06:00
Christoph Hellwig f936b06ae5 bcache: clean up do_btree_node_write a bit
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 <willy@infradead.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Acked-by: Coly Li <colyli@suse.de>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-30 09:26:11 -06:00
Coly Li cdca22bcbc bcache: remove redundant LIST_HEAD(journal) from run_cache_set()
Commit 95f18c9d13 ("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: 95f18c9d13 ("bcache: avoid potential memleak of list of journal_replay(s) in the CACHE_SYNC branch of run_cache_set")
Reported-by: Juha Aatrokoski <juha.aatrokoski@aalto.fi>
Cc: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-30 08:20:46 -06:00
Shenghui Wang 95f18c9d13 bcache: avoid potential memleak of list of journal_replay(s) in the CACHE_SYNC branch of run_cache_set
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 <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:29 -06:00
Shenghui Wang f16277ca20 bcache: fix wrong usage use-after-freed on keylist in out_nocoalesce branch of btree_gc_coalesce
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 <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:29 -06:00
Tang Junhui 631207314d bcache: fix failure in journal relplay
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 <tang.junhui.linux@gmail.com>
Tested-by: Dennis Schridde <devurandom@gmx.net>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:28 -06:00
Coly Li eb8cbb6df3 bcache: improve bcache_reboot()
This patch tries to release mutex bch_register_lock early, to give
chance to stop cache set and bcache device early.

This patch also expends time out of stopping all bcache device from
2 seconds to 10 seconds, because stopping writeback rate update worker
may delay for 5 seconds, 2 seconds is not enough.

After this patch applied, stopping bcache devices during system reboot
or shutdown is very hard to be observed any more.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:28 -06:00
Coly Li 63d63b51d7 bcache: add comments for closure_fn to be called in closure_queue()
Add code comments to explain which call back function might be called
for the closure_queue(). This is an effort to make code to be more
understandable for readers.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:28 -06:00
Coly Li bb6d355c2a bcache: Add comments for blkdev_put() in registration code path
Add comments to explain why in register_bcache() blkdev_put() won't
be called in two location. Add comments to explain why blkdev_put()
must be called in register_cache() when cache_alloc() failed.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:28 -06:00
Coly Li 88c12d42d2 bcache: add error check for calling register_bdev()
This patch adds return value to register_bdev(). Then if failure happens
inside register_bdev(), its caller register_bcache() may detect and
handle the failure more properly.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:28 -06:00
Coly Li 68d10e6979 bcache: return error immediately in bch_journal_replay()
When failure happens inside bch_journal_replay(), calling
cache_set_err_on() and handling the failure in async way is not a good
idea. Because after bch_journal_replay() returns, registering code will
continue to execute following steps, and unregistering code triggered
by cache_set_err_on() is running in same time. First it is unnecessary
to handle failure and unregister cache set in an async way, second there
might be potential race condition to run register and unregister code
for same cache set.

So in this patch, if failure happens in bch_journal_replay(), we don't
call cache_set_err_on(), and just print out the same error message to
kernel message buffer, then return -EIO immediately caller. Then caller
can detect such failure and handle it in synchrnozied way.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:28 -06:00
Coly Li 2d17456eb1 bcache: add comments for kobj release callback routine
Bcache has several routines to release resources in implicit way, they
are called when the associated kobj released. This patch adds code
comments to notice when and which release callback will be called,
- When dc->disk.kobj released:
  void bch_cached_dev_release(struct kobject *kobj)
- When d->kobj released:
  void bch_flash_dev_release(struct kobject *kobj)
- When c->kobj released:
  void bch_cache_set_release(struct kobject *kobj)
- When ca->kobj released
  void bch_cache_release(struct kobject *kobj)

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:28 -06:00
Coly Li ce3e4cfb59 bcache: add failure check to run_cache_set() for journal replay
Currently run_cache_set() has no return value, if there is failure in
bch_journal_replay(), the caller of run_cache_set() has no idea about
such failure and just continue to execute following code after
run_cache_set().  The internal failure is triggered inside
bch_journal_replay() and being handled in async way. This behavior is
inefficient, while failure handling inside bch_journal_replay(), cache
register code is still running to start the cache set. Registering and
unregistering code running as same time may introduce some rare race
condition, and make the code to be more hard to be understood.

This patch adds return value to run_cache_set(), and returns -EIO if
bch_journal_rreplay() fails. Then caller of run_cache_set() may detect
such failure and stop registering code flow immedidately inside
register_cache_set().

If journal replay fails, run_cache_set() can report error immediately
to register_cache_set(). This patch makes the failure handling for
bch_journal_replay() be in synchronized way, easier to understand and
debug, and avoid poetential race condition for register-and-unregister
in same time.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:28 -06:00
Coly Li 1bee2addc0 bcache: never set KEY_PTRS of journal key to 0 in journal_reclaim()
In journal_reclaim() ja->cur_idx of each cache will be update to
reclaim available journal buckets. Variable 'int n' is used to count how
many cache is successfully reclaimed, then n is set to c->journal.key
by SET_KEY_PTRS(). Later in journal_write_unlocked(), a for_each_cache()
loop will write the jset data onto each cache.

The problem is, if all jouranl buckets on each cache is full, the
following code in journal_reclaim(),

529 for_each_cache(ca, c, iter) {
530       struct journal_device *ja = &ca->journal;
531       unsigned int next = (ja->cur_idx + 1) % ca->sb.njournal_buckets;
532
533       /* No space available on this device */
534       if (next == ja->discard_idx)
535               continue;
536
537       ja->cur_idx = next;
538       k->ptr[n++] = MAKE_PTR(0,
539                         bucket_to_sector(c, ca->sb.d[ja->cur_idx]),
540                         ca->sb.nr_this_dev);
541 }
542
543 bkey_init(k);
544 SET_KEY_PTRS(k, n);

If there is no available bucket to reclaim, the if() condition at line
534 will always true, and n remains 0. Then at line 544, SET_KEY_PTRS()
will set KEY_PTRS field of c->journal.key to 0.

Setting KEY_PTRS field of c->journal.key to 0 is wrong. Because in
journal_write_unlocked() the journal data is written in following loop,

649	for (i = 0; i < KEY_PTRS(k); i++) {
650-671		submit journal data to cache device
672	}

If KEY_PTRS field is set to 0 in jouranl_reclaim(), the journal data
won't be written to cache device here. If system crahed or rebooted
before bkeys of the lost journal entries written into btree nodes, data
corruption will be reported during bcache reload after rebooting the
system.

Indeed there is only one cache in a cache set, there is no need to set
KEY_PTRS field in journal_reclaim() at all. But in order to keep the
for_each_cache() logic consistent for now, this patch fixes the above
problem by not setting 0 KEY_PTRS of journal key, if there is no bucket
available to reclaim.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:27 -06:00
Coly Li 14215ee01f bcache: move definition of 'int ret' out of macro read_bucket()
'int ret' is defined as a local variable inside macro read_bucket().
Since this macro is called multiple times, and following patches will
use a 'int ret' variable in bch_journal_read(), this patch moves
definition of 'int ret' from macro read_bucket() to range of function
bch_journal_read().

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:27 -06:00
Liang Chen a4b732a248 bcache: fix a race between cache register and cacheset unregister
There is a race between cache device register and cache set unregister.
For an already registered cache device, register_bcache will call
bch_is_open to iterate through all cachesets and check every cache
there. The race occurs if cache_set_free executes at the same time and
clears the caches right before ca is dereferenced in bch_is_open_cache.
To close the race, let's make sure the clean up work is protected by
the bch_register_lock as well.

This issue can be reproduced as follows,
while true; do echo /dev/XXX> /sys/fs/bcache/register ; done&
while true; do echo 1> /sys/block/XXX/bcache/set/unregister ; done &

and results in the following oops,

[  +0.000053] BUG: unable to handle kernel NULL pointer dereference at 0000000000000998
[  +0.000457] #PF error: [normal kernel read fault]
[  +0.000464] PGD 800000003ca9d067 P4D 800000003ca9d067 PUD 3ca9c067 PMD 0
[  +0.000388] Oops: 0000 [#1] SMP PTI
[  +0.000269] CPU: 1 PID: 3266 Comm: bash Not tainted 5.0.0+ #6
[  +0.000346] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.fc28 04/01/2014
[  +0.000472] RIP: 0010:register_bcache+0x1829/0x1990 [bcache]
[  +0.000344] Code: b0 48 83 e8 50 48 81 fa e0 e1 10 c0 0f 84 a9 00 00 00 48 89 c6 48 89 ca 0f b7 ba 54 04 00 00 4c 8b 82 60 0c 00 00 85 ff 74 2f <49> 3b a8 98 09 00 00 74 4e 44 8d 47 ff 31 ff 49 c1 e0 03 eb 0d
[  +0.000839] RSP: 0018:ffff92ee804cbd88 EFLAGS: 00010202
[  +0.000328] RAX: ffffffffc010e190 RBX: ffff918b5c6b5000 RCX: ffff918b7d8e0000
[  +0.000399] RDX: ffff918b7d8e0000 RSI: ffffffffc010e190 RDI: 0000000000000001
[  +0.000398] RBP: ffff918b7d318340 R08: 0000000000000000 R09: ffffffffb9bd2d7a
[  +0.000385] R10: ffff918b7eb253c0 R11: ffffb95980f51200 R12: ffffffffc010e1a0
[  +0.000411] R13: fffffffffffffff2 R14: 000000000000000b R15: ffff918b7e232620
[  +0.000384] FS:  00007f955bec2740(0000) GS:ffff918b7eb00000(0000) knlGS:0000000000000000
[  +0.000420] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  +0.000801] CR2: 0000000000000998 CR3: 000000003cad6000 CR4: 00000000001406e0
[  +0.000837] Call Trace:
[  +0.000682]  ? _cond_resched+0x10/0x20
[  +0.000691]  ? __kmalloc+0x131/0x1b0
[  +0.000710]  kernfs_fop_write+0xfa/0x170
[  +0.000733]  __vfs_write+0x2e/0x190
[  +0.000688]  ? inode_security+0x10/0x30
[  +0.000698]  ? selinux_file_permission+0xd2/0x120
[  +0.000752]  ? security_file_permission+0x2b/0x100
[  +0.000753]  vfs_write+0xa8/0x1a0
[  +0.000676]  ksys_write+0x4d/0xb0
[  +0.000699]  do_syscall_64+0x3a/0xf0
[  +0.000692]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:27 -06:00
George Spelvin 3a3947271c bcache: Clean up bch_get_congested()
There are a few nits in this function.  They could in theory all
be separate patches, but that's probably taking small commits
too far.

1) I added a brief comment saying what it does.

2) I like to declare pointer parameters "const" where possible
   for documentation reasons.

3) It uses bitmap_weight(&rand, BITS_PER_LONG) to compute the Hamming
weight of a 32-bit random number (giving a random integer with
mean 16 and variance 8).  Passing by reference in a 64-bit variable
is silly; just use hweight32().

4) Its helper function fract_exp_two is unnecessarily tangled.
Gcc can optimize the multiply by (1 << x) to a shift, but it can
be written in a much more straightforward way at the cost of one
more bit of internal precision.  Some analysis reveals that this
bit is always available.

This shrinks the object code for fract_exp_two(x, 6) from 23 bytes:

0000000000000000 <foo1>:
   0:   89 f9                   mov    %edi,%ecx
   2:   c1 e9 06                shr    $0x6,%ecx
   5:   b8 01 00 00 00          mov    $0x1,%eax
   a:   d3 e0                   shl    %cl,%eax
   c:   83 e7 3f                and    $0x3f,%edi
   f:   d3 e7                   shl    %cl,%edi
  11:   c1 ef 06                shr    $0x6,%edi
  14:   01 f8                   add    %edi,%eax
  16:   c3                      retq

To 19:

0000000000000017 <foo2>:
  17:   89 f8                   mov    %edi,%eax
  19:   83 e0 3f                and    $0x3f,%eax
  1c:   83 c0 40                add    $0x40,%eax
  1f:   89 f9                   mov    %edi,%ecx
  21:   c1 e9 06                shr    $0x6,%ecx
  24:   d3 e0                   shl    %cl,%eax
  26:   c1 e8 06                shr    $0x6,%eax
  29:   c3                      retq

(Verified with 0 <= frac_bits <= 8, 0 <= x < 16<<frac_bits;
both versions produce the same output.)

5) And finally, the call to bch_get_congested() in check_should_bypass()
is separated from the use of the value by multiple tests which
could moot the need to compute it.  Move the computation down to
where it's needed.  This also saves a local register to hold the
computed value.

Signed-off-by: George Spelvin <lkml@sdf.org>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:27 -06:00
Geliang Tang 792732d985 bcache: use kmemdup_nul for CACHED_LABEL buffer
This patch uses kmemdup_nul to create a NUL-terminated string from
dc->sb.label. This is better than open coding it.

With this, we can move env[2] initialization into env[] array to make
code more elegant.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:27 -06:00
Arnd Bergmann 78d4eb8ad9 bcache: avoid clang -Wunintialized warning
clang has identified a code path in which it thinks a
variable may be unused:

drivers/md/bcache/alloc.c:333:4: error: variable 'bucket' is used uninitialized whenever 'if' condition is false
      [-Werror,-Wsometimes-uninitialized]
                        fifo_pop(&ca->free_inc, bucket);
                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/md/bcache/util.h:219:27: note: expanded from macro 'fifo_pop'
 #define fifo_pop(fifo, i)       fifo_pop_front(fifo, (i))
                                ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/md/bcache/util.h:189:6: note: expanded from macro 'fifo_pop_front'
        if (_r) {                                                       \
            ^~
drivers/md/bcache/alloc.c:343:46: note: uninitialized use occurs here
                        allocator_wait(ca, bch_allocator_push(ca, bucket));
                                                                  ^~~~~~
drivers/md/bcache/alloc.c:287:7: note: expanded from macro 'allocator_wait'
                if (cond)                                               \
                    ^~~~
drivers/md/bcache/alloc.c:333:4: note: remove the 'if' if its condition is always true
                        fifo_pop(&ca->free_inc, bucket);
                        ^
drivers/md/bcache/util.h:219:27: note: expanded from macro 'fifo_pop'
 #define fifo_pop(fifo, i)       fifo_pop_front(fifo, (i))
                                ^
drivers/md/bcache/util.h:189:2: note: expanded from macro 'fifo_pop_front'
        if (_r) {                                                       \
        ^
drivers/md/bcache/alloc.c:331:15: note: initialize the variable 'bucket' to silence this warning
                        long bucket;
                                   ^

This cannot happen in practice because we only enter the loop
if there is at least one element in the list.

Slightly rearranging the code makes this clearer to both the
reader and the compiler, which avoids the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:27 -06:00
Guoju Fang 4e0c04ec3a bcache: fix inaccurate result of unused buckets
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 <fangguoju@gmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:27 -06:00
Guoju Fang 1568ee7e3c bcache: fix crashes stopping bcache device before read miss done
The bio from upper layer is considered completed when bio_complete()
returns. In most scenarios bio_complete() is called in search_free(),
but when read miss happens, the bio_compete() is called when backing
device reading completed, while the struct search is still in use until
cache inserting finished.

If someone stops the bcache device just then, the device may be closed
and released, but after cache inserting finished the struct search will
access a freed struct cached_dev.

This patch add the reference of bcache device before bio_complete() when
read miss happens, and put it after the search is not used.

Signed-off-by: Guoju Fang <fangguoju@gmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-24 10:56:27 -06:00
Ming Lei 6dc4f100c1 block: allow bio_for_each_segment_all() to iterate over multi-page bvec
This patch introduces one extra iterator variable to bio_for_each_segment_all(),
then we can allow bio_for_each_segment_all() to iterate over multi-page bvec.

Given it is just one mechannical & simple change on all bio_for_each_segment_all()
users, this patch does tree-wide change in one single patch, so that we can
avoid to use a temporary helper for this conversion.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-15 08:40:11 -07:00
Ming Lei 2e1f4f4d24 bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages()
bch_bio_alloc_pages() is always called on one new bio, so it is safe
to access the bvec table directly. Given it is the only kind of this
case, open code the bvec table access since bio_for_each_segment_all()
will be changed to support for iterating over multipage bvec.

Acked-by: Coly Li <colyli@suse.de>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-15 08:40:11 -07:00
Coly Li dc7292a5bc bcache: use (REQ_META|REQ_PRIO) to indicate bio for metadata
In 'commit 752f66a75a ("bcache: use REQ_PRIO to indicate bio for
metadata")' REQ_META is replaced by REQ_PRIO to indicate metadata bio.
This assumption is not always correct, e.g. XFS uses REQ_META to mark
metadata bio other than REQ_PRIO. This is why Nix noticed that bcache
does not cache metadata for XFS after the above commit.

Thanks to Dave Chinner, he explains the difference between REQ_META and
REQ_PRIO from view of file system developer. Here I quote part of his
explanation from mailing list,
   REQ_META is used for metadata. REQ_PRIO is used to communicate to
   the lower layers that the submitter considers this IO to be more
   important that non REQ_PRIO IO and so dispatch should be expedited.

   IOWs, if the filesystem considers metadata IO to be more important
   that user data IO, then it will use REQ_PRIO | REQ_META rather than
   just REQ_META.

Then it seems bios with REQ_META or REQ_PRIO should both be cached for
performance optimation, because they are all probably low I/O latency
demand by upper layer (e.g. file system).

So in this patch, when we want to decide whether to bypass the cache,
REQ_META and REQ_PRIO are both checked. Then both metadata and
high priority I/O requests will be handled properly.

Reported-by: Nix <nix@esperi.org.uk>
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Andre Noll <maan@tuebingen.mpg.de>
Tested-by: Nix <nix@esperi.org.uk>
Cc: stable@vger.kernel.org
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:33 -07:00
Coly Li a91fbda49f bcache: fix input overflow to cache set sysfs file io_error_halflife
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 <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:33 -07:00
Coly Li b15008403b bcache: fix input overflow to cache set io_error_limit
c->error_limit is in type unsigned int, it is set via cache set sysfs
file io_error_limit. Inside the bcache code, input string is converted
by strtoul_or_return() and set the converted value to c->error_limit.

Because the converted value is unsigned long, and c->error_limit is
unsigned int, if the input is large enought, overflow will happen to
c->error_limit.

This patch uses sysfs_strtoul_clamp() to convert input string, and set
the range in [0, UINT_MAX] to avoid the potential overflow.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:32 -07:00
Coly Li 453745fbbe bcache: fix input overflow to journal_delay_ms
c->journal_delay_ms is in type unsigned short, it is set via sysfs
interface and converted by sysfs_strtoul() from input string to
unsigned short value. Therefore overflow to unsigned short might be
happen when the converted value exceed USHRT_MAX. e.g. writing
65536 into sysfs file journal_delay_ms, c->journal_delay_ms is set to
0.

This patch uses sysfs_strtoul_clamp() to convert the input string and
limit value range in [0, USHRT_MAX], to avoid the input overflow.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:32 -07:00
Coly Li dab71b2db9 bcache: fix input overflow to writeback_rate_minimum
dc->writeback_rate_minimum is type unsigned integer variable, it is set
via sysfs interface, and converte from input string to unsigned integer
by d_strtoul_nonzero(). When the converted input value is larger than
UINT_MAX, overflow to unsigned integer happens.

This patch fixes the overflow by using sysfs_strotoul_clamp() to
convert input string and limit the value in range [1, UINT_MAX], then
the overflow can be avoided.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:32 -07:00
Coly Li 5b5fd3c94e bcache: fix potential div-zero error of writeback_rate_p_term_inverse
Current code already uses d_strtoul_nonzero() to convert input string
to an unsigned integer, to make sure writeback_rate_p_term_inverse
won't be zero value. But overflow may happen when converting input
string to an unsigned integer value by d_strtoul_nonzero(), then
dc->writeback_rate_p_term_inverse can still be set to 0 even if the
sysfs file input value is not zero, e.g. 4294967296 (a.k.a UINT_MAX+1).

If dc->writeback_rate_p_term_inverse is set to 0, it might cause a
dev-zero error in following code from __update_writeback_rate(),
	int64_t proportional_scaled =
		div_s64(error, dc->writeback_rate_p_term_inverse);

This patch replaces d_strtoul_nonzero() by sysfs_strtoul_clamp() and
limit the value range in [1, UINT_MAX]. Then the unsigned integer
overflow and dev-zero error can be avoided.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:32 -07:00
Coly Li c3b75a2199 bcache: fix potential div-zero error of writeback_rate_i_term_inverse
dc->writeback_rate_i_term_inverse can be set via sysfs interface. It is
in type unsigned int, and convert from input string by d_strtoul(). The
problem is d_strtoul() does not check valid range of the input, if
4294967296 is written into sysfs file writeback_rate_i_term_inverse,
an overflow of unsigned integer will happen and value 0 is set to
dc->writeback_rate_i_term_inverse.

In writeback.c:__update_writeback_rate(), there are following lines of
code,
      integral_scaled = div_s64(dc->writeback_rate_integral,
                      dc->writeback_rate_i_term_inverse);
If dc->writeback_rate_i_term_inverse is set to 0 via sysfs interface,
a div-zero error might be triggered in the above code.

Therefore we need to add a range limitation in the sysfs interface,
this is what this patch does, use sysfs_stroul_clamp() to replace
d_strtoul() and restrict the input range in [1, UINT_MAX].

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:32 -07:00
Coly Li 369d21a73a bcache: fix input overflow to writeback_delay
Sysfs file writeback_delay is used to configure dc->writeback_delay
which is type unsigned int. But bcache code uses sysfs_strtoul() to
convert the input string, therefore it might be overflowed if the input
value is too large. E.g. input value is 4294967296 but indeed 0 is
set to dc->writeback_delay.

This patch uses sysfs_strtoul_clamp() to convert the input string and
set the result value range in [0, UINT_MAX] to avoid such unsigned
integer overflow.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:32 -07:00
Coly Li f5c0b95d2e bcache: use sysfs_strtoul_bool() to set bit-field variables
When setting bcache parameters via sysfs, there are some variables are
defined as bit-field value. Current bcache code in sysfs.c uses either
d_strtoul() or sysfs_strtoul() to convert the input string to unsigned
integer value and set it to the corresponded bit-field value.

The problem is, the bit-field value only takes the lowest bit of the
converted value. If input is 2, the expected value (like bool value)
of the bit-field value should be 1, but indeed it is 0.

The following sysfs files for bit-field variables have such problem,
	bypass_torture_test,	for dc->bypass_torture_test
	writeback_metadata,	for dc->writeback_metadata
	writeback_running,	for dc->writeback_running
	verify,			for c->verify
	key_merging_disabled,	for c->key_merging_disabled
	gc_always_rewrite,	for c->gc_always_rewrite
	btree_shrinker_disabled,for c->shrinker_disabled
	copy_gc_enabled,	for c->copy_gc_enabled

This patch uses sysfs_strtoul_bool() to set such bit-field variables,
then if the converted value is non-zero, the bit-field variables will
be set to 1, like setting a bool value like expensive_debug_checks.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:32 -07:00
Coly Li e4db37fb69 bcache: add sysfs_strtoul_bool() for setting bit-field variables
When setting bool values via sysfs interface, e.g. writeback_metadata,
if writing 1 into writeback_metadata file, dc->writeback_metadata is
set to 1, but if writing 2 into the file, dc->writeback_metadata is
0. This is misleading, a better result should be 1 for all non-zero
input value.

It is because dc->writeback_metadata is a bit-field variable, and
current code simply use d_strtoul() to convert a string into integer
and takes the lowest bit value. To fix such error, we need a routine
to convert the input string into unsigned integer, and set target
variable to 1 if the converted integer is non-zero.

This patch introduces a new macro called sysfs_strtoul_bool(), it can
be used to convert input string into bool value, we can use it to set
bool value for bit-field vairables.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:32 -07:00
Coly Li 8c27a3953e bcache: fix input overflow to sequential_cutoff
People may set sequential_cutoff of a cached device via sysfs file,
but current code does not check input value overflow. E.g. if value
4294967295 (UINT_MAX) is written to file sequential_cutoff, its value
is 4GB, but if 4294967296 (UINT_MAX + 1) is written into, its value
will be 0. This is an unexpected behavior.

This patch replaces d_strtoi_h() by sysfs_strtoul_clamp() to convert
input string to unsigned integer value, and limit its range in
[0, UINT_MAX]. Then the input overflow can be fixed.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:32 -07:00
Coly Li f54478c6e2 bcache: fix input integer overflow of congested threshold
Cache set congested threshold values congested_read_threshold_us and
congested_write_threshold_us can be set via sysfs interface. These
two values are 'unsigned int' type, but sysfs interface uses strtoul
to convert input string. So if people input a large number like
9999999999, the value indeed set is 1410065407, which is not expected
behavior.

This patch replaces sysfs_strtoul() by sysfs_strtoul_clamp() when
convert input string to unsigned int value, and set value range in
[0, UINT_MAX], to avoid the above integer overflow errors.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:31 -07:00
Coly Li 596b5a5dd1 bcache: improve sysfs_strtoul_clamp()
Currently sysfs_strtoul_clamp() is defined as,
 82 #define sysfs_strtoul_clamp(file, var, min, max)                   \
 83 do {                                                               \
 84         if (attr == &sysfs_ ## file)                               \
 85                 return strtoul_safe_clamp(buf, var, min, max)      \
 86                         ?: (ssize_t) size;                         \
 87 } while (0)

The problem is, if bit width of var is less then unsigned long, min and
max may not protect var from integer overflow, because overflow happens
in strtoul_safe_clamp() before checking min and max.

To fix such overflow in sysfs_strtoul_clamp(), to make min and max take
effect, this patch adds an unsigned long variable, and uses it to macro
strtoul_safe_clamp() to convert an unsigned long value in range defined
by [min, max]. Then assign this value to var. By this method, if bit
width of var is less than unsigned long, integer overflow won't happen
before min and max are checking.

Now sysfs_strtoul_clamp() can properly handle smaller data type like
unsigned int, of cause min and max should be defined in range of
unsigned int too.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:31 -07:00
Tang Junhui 58ac323084 bcache: treat stale && dirty keys as bad keys
Stale && dirty keys can be produced in the follow way:
After writeback in write_dirty_finish(), dirty keys k1 will
replace by clean keys k2
==>ret = bch_btree_insert(dc->disk.c, &keys, NULL, &w->key);
==>btree_insert_fn(struct btree_op *b_op, struct btree *b)
==>static int bch_btree_insert_node(struct btree *b,
       struct btree_op *op,
       struct keylist *insert_keys,
       atomic_t *journal_ref,
Then two steps:
A) update k1 to k2 in btree node memory;
   bch_btree_insert_keys(b, op, insert_keys, replace_key)
B) Write the bset(contains k2) to cache disk by a 30s delay work
   bch_btree_leaf_dirty(b, journal_ref).
But before the 30s delay work write the bset to cache device,
these things happened:
A) GC works, and reclaim the bucket k2 point to;
B) Allocator works, and invalidate the bucket k2 point to,
   and increase the gen of the bucket, and place it into free_inc
   fifo;
C) Until now, the 30s delay work still does not finish work,
   so in the disk, the key still is k1, it is dirty and stale
   (its gen is smaller than the gen of the bucket). and then the
   machine power off suddenly happens;
D) When the machine power on again, after the btree reconstruction,
   the stale dirty key appear.

In bch_extent_bad(), when expensive_debug_checks is off, it would
treat the dirty key as good even it is stale keys, and it would
cause bellow probelms:
A) In read_dirty() it would cause machine crash:
   BUG_ON(ptr_stale(dc->disk.c, &w->key, 0));
B) It could be worse when reads hits stale dirty keys, it would
   read old incorrect data.

This patch tolerate the existence of these stale && dirty keys,
and treat them as bad key in bch_extent_bad().

(Coly Li: fix indent which was modified by sender's email client)

Signed-off-by: Tang Junhui <tang.junhui.linux@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:31 -07:00
Colin Ian King e8cf978dff bcache: fix indentation issue, remove tabs on a hunk of code
There is a hunk of code that is indented one level too deep, fix this
by removing the extra tabs.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:31 -07:00
Coly Li d4610456cf bcache: export backing_dev_uuid via sysfs
When there are multiple bcache devices, after a reboot the name of
bcache devices may change (e.g. current /dev/bcache1 was /dev/bcache0
before reboot). Therefore we need the backing device UUID (sb.uuid) to
identify each bcache device.

Backing device uuid can be found by program bcache-super-show, but
directly exporting backing_dev_uuid by sysfs file
/sys/block/bcache<?>/bcache/backing_dev_uuid is a much simpler method.

With backing_dev_uuid, and partition uuids from /dev/disk/by-partuuid/,
now we can identify each bcache device and its partitions conveniently.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:31 -07:00
Coly Li 926d19465b bcache: export backing_dev_name via sysfs
This patch export dc->backing_dev_name to sysfs file
/sys/block/bcache<?>/bcache/backing_dev_name, then people or user space
tools may know the backing device name of this bcache device.

Of cause it can be done by parsing sysfs links, but this method can be
much simpler to find the link between bcache device and backing device.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:31 -07:00
Coly Li 83ff9318c4 bcache: not use hard coded memset size in bch_cache_accounting_clear()
In stats.c:bch_cache_accounting_clear(), a hard coded number '7' is
used in memset(). It is because in struct cache_stats, there are 7
atomic_t type members. This is not good when new members added into
struct stats, the hard coded number will only clear part of memory.

This patch replaces 'sizeof(unsigned long) * 7' by more generic
'sizeof(struct cache_stats))', to avoid potential error if new
member added into struct cache_stats.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:31 -07:00
Daniel Axtens 9951379b0c bcache: never writeback a discard operation
Some users see panics like the following when performing fstrim on a
bcached volume:

[  529.803060] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[  530.183928] #PF error: [normal kernel read fault]
[  530.412392] PGD 8000001f42163067 P4D 8000001f42163067 PUD 1f42168067 PMD 0
[  530.750887] Oops: 0000 [#1] SMP PTI
[  530.920869] CPU: 10 PID: 4167 Comm: fstrim Kdump: loaded Not tainted 5.0.0-rc1+ #3
[  531.290204] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 12/27/2015
[  531.693137] RIP: 0010:blk_queue_split+0x148/0x620
[  531.922205] Code: 60 38 89 55 a0 45 31 db 45 31 f6 45 31 c9 31 ff 89 4d 98 85 db 0f 84 7f 04 00 00 44 8b 6d 98 4c 89 ee 48 c1 e6 04 49 03 70 78 <8b> 46 08 44 8b 56 0c 48
8b 16 44 29 e0 39 d8 48 89 55 a8 0f 47 c3
[  532.838634] RSP: 0018:ffffb9b708df39b0 EFLAGS: 00010246
[  533.093571] RAX: 00000000ffffffff RBX: 0000000000046000 RCX: 0000000000000000
[  533.441865] RDX: 0000000000000200 RSI: 0000000000000000 RDI: 0000000000000000
[  533.789922] RBP: ffffb9b708df3a48 R08: ffff940d3b3fdd20 R09: 0000000000000000
[  534.137512] R10: ffffb9b708df3958 R11: 0000000000000000 R12: 0000000000000000
[  534.485329] R13: 0000000000000000 R14: 0000000000000000 R15: ffff940d39212020
[  534.833319] FS:  00007efec26e3840(0000) GS:ffff940d1f480000(0000) knlGS:0000000000000000
[  535.224098] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  535.504318] CR2: 0000000000000008 CR3: 0000001f4e256004 CR4: 00000000001606e0
[  535.851759] Call Trace:
[  535.970308]  ? mempool_alloc_slab+0x15/0x20
[  536.174152]  ? bch_data_insert+0x42/0xd0 [bcache]
[  536.403399]  blk_mq_make_request+0x97/0x4f0
[  536.607036]  generic_make_request+0x1e2/0x410
[  536.819164]  submit_bio+0x73/0x150
[  536.980168]  ? submit_bio+0x73/0x150
[  537.149731]  ? bio_associate_blkg_from_css+0x3b/0x60
[  537.391595]  ? _cond_resched+0x1a/0x50
[  537.573774]  submit_bio_wait+0x59/0x90
[  537.756105]  blkdev_issue_discard+0x80/0xd0
[  537.959590]  ext4_trim_fs+0x4a9/0x9e0
[  538.137636]  ? ext4_trim_fs+0x4a9/0x9e0
[  538.324087]  ext4_ioctl+0xea4/0x1530
[  538.497712]  ? _copy_to_user+0x2a/0x40
[  538.679632]  do_vfs_ioctl+0xa6/0x600
[  538.853127]  ? __do_sys_newfstat+0x44/0x70
[  539.051951]  ksys_ioctl+0x6d/0x80
[  539.212785]  __x64_sys_ioctl+0x1a/0x20
[  539.394918]  do_syscall_64+0x5a/0x110
[  539.568674]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

We have observed it where both:
1) LVM/devmapper is involved (bcache backing device is LVM volume) and
2) writeback cache is involved (bcache cache_mode is writeback)

On one machine, we can reliably reproduce it with:

 # echo writeback > /sys/block/bcache0/bcache/cache_mode
   (not sure whether above line is required)
 # mount /dev/bcache0 /test
 # for i in {0..10}; do
	file="$(mktemp /test/zero.XXX)"
	dd if=/dev/zero of="$file" bs=1M count=256
	sync
	rm $file
    done
  # fstrim -v /test

Observing this with tracepoints on, we see the following writes:

fstrim-18019 [022] .... 91107.302026: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 4260112 + 196352 hit 0 bypass 1
fstrim-18019 [022] .... 91107.302050: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 4456464 + 262144 hit 0 bypass 1
fstrim-18019 [022] .... 91107.302075: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 4718608 + 81920 hit 0 bypass 1
fstrim-18019 [022] .... 91107.302094: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 5324816 + 180224 hit 0 bypass 1
fstrim-18019 [022] .... 91107.302121: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 5505040 + 262144 hit 0 bypass 1
fstrim-18019 [022] .... 91107.302145: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 5767184 + 81920 hit 0 bypass 1
fstrim-18019 [022] .... 91107.308777: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 6373392 + 180224 hit 1 bypass 0
<crash>

Note the final one has different hit/bypass flags.

This is because in should_writeback(), we were hitting a case where
the partial stripe condition was returning true and so
should_writeback() was returning true early.

If that hadn't been the case, it would have hit the would_skip test, and
as would_skip == s->iop.bypass == true, should_writeback() would have
returned false.

Looking at the git history from 'commit 72c270612b ("bcache: Write out
full stripes")', it looks like the idea was to optimise for raid5/6:

       * If a stripe is already dirty, force writes to that stripe to
	 writeback mode - to help build up full stripes of dirty data

To fix this issue, make sure that should_writeback() on a discard op
never returns true.

More details of debugging:
https://www.spinics.net/lists/linux-bcache/msg06996.html

Previous reports:
 - https://bugzilla.kernel.org/show_bug.cgi?id=201051
 - https://bugzilla.kernel.org/show_bug.cgi?id=196103
 - https://www.spinics.net/lists/linux-bcache/msg06885.html

(Coly Li: minor modification to follow maximum 75 chars per line rule)

Cc: Kent Overstreet <koverstreet@google.com>
Cc: stable@vger.kernel.org
Fixes: 72c270612b ("bcache: Write out full stripes")
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:31 -07:00
Guoju Fang e78bd0d26f bcache: print number of keys in trace_bcache_journal_write
Sometimes flush journal may be very frequent, so it's useful to dump
number of keys every time write journal.

Signed-off-by: Guoju Fang <fangguoju@gmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Coly Li cc38ca7ed5 bcache: set writeback_percent in a flexible range
Because CUTOFF_WRITEBACK is defined as 40, so before the changes of
dynamic cutoff writeback values, writeback_percent is limited to [0,
CUTOFF_WRITEBACK]. Any value larger than CUTOFF_WRITEBACK will be fixed
up to 40.

Now cutof writeback limit is a dynamic value bch_cutoff_writeback, so
the range of writeback_percent can be a more flexible range as [0,
bch_cutoff_writeback]. The flexibility is, it can be expended to a
larger or smaller range than [0, 40], depends on how value
bch_cutoff_writeback is specified.

The default value is still strongly recommended to most of users for
most of workloads. But for people who want to do research on bcache
writeback perforamnce tuning, they may have chance to specify more
flexible writeback_percent in range [0, 70].

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Coly Li 9aaf516546 bcache: make cutoff_writeback and cutoff_writeback_sync tunable
Currently the cutoff writeback and cutoff writeback sync thresholds are
defined by CUTOFF_WRITEBACK (40) and CUTOFF_WRITEBACK_SYNC (70) as
static values. Most of time these they work fine, but when people want
to do research on bcache writeback mode performance tuning, there is no
chance to modify the soft and hard cutoff writeback values.

This patch introduces two module parameters bch_cutoff_writeback_sync
and bch_cutoff_writeback which permit people to tune the values when
loading bcache.ko. If they are not specified by module loading, current
values CUTOFF_WRITEBACK_SYNC and CUTOFF_WRITEBACK will be used as
default and nothing changes.

When people want to tune this two values,
- cutoff_writeback can be set in range [1, 70]
- cutoff_writeback_sync can be set in range [1, 90]
- cutoff_writeback always <= cutoff_writeback_sync

The default values are strongly recommended to most of users for most of
workloads. Anyway, if people wants to take their own risk to do research
on new writeback cutoff tuning for their own workload, now they can make
it.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Coly Li 009673d02f bcache: add MODULE_DESCRIPTION information
This patch moves MODULE_AUTHOR and MODULE_LICENSE to end of super.c, and
add MODULE_DESCRIPTION("Bcache: a Linux block layer cache").

This is preparation for adding module parameters.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Coly Li 7a671d8ef8 bcache: option to automatically run gc thread after writeback
The option gc_after_writeback is disabled by default, because garbage
collection will discard SSD data which drops cached data.

Echo 1 into /sys/fs/bcache/<UUID>/internal/gc_after_writeback will
enable this option, which wakes up gc thread when writeback accomplished
and all cached data is clean.

This option is helpful for people who cares writing performance more. In
heavy writing workload, all cached data can be clean only happens when
writeback thread cleans all cached data in I/O idle time. In such
situation a following gc running may help to shrink bcache B+ tree and
discard more clean data, which may be helpful for future writing
requests.

If you are not sure whether this is helpful for your own workload,
please leave it as disabled by default.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Coly Li cb07ad6368 bcache: introduce force_wake_up_gc()
Garbage collection thread starts to work when c->sectors_to_gc is
negative value, otherwise nothing will happen even the gc thread is
woken up by wake_up_gc().

force_wake_up_gc() sets c->sectors_to_gc to -1 before calling
wake_up_gc(), then gc thread may have chance to run if no one else sets
c->sectors_to_gc to a positive value before gc_should_run().

This routine can be called where the gc thread is woken up and required
to run in force.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Shenghui Wang f383ae300c bcache: cannot set writeback_running via sysfs if no writeback kthread created
"echo 1 > writeback_running" marks writeback_running even if no
writeback kthread created as "d_strtoul(writeback_running)" will simply
set dc-> writeback_running without checking the existence of
dc->writeback_thread.

Add check for setting writeback_running via sysfs: if no writeback
kthread available, reject setting to 1.

v2 -> v3:
  * Make message on wrong assignment more clear.
  * Print name of bcache device instead of name of backing device.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Shenghui Wang 79b791466e bcache: do not mark writeback_running too early
A fresh backing device is not attached to any cache_set, and
has no writeback kthread created until first attached to some
cache_set.

But bch_cached_dev_writeback_init run
"
	dc->writeback_running		= true;
	WARN_ON(test_and_clear_bit(BCACHE_DEV_WB_RUNNING,
			&dc->disk.flags));
"
for any newly formatted backing devices.

For a fresh standalone backing device, we can get something like
following even if no writeback kthread created:
------------------------
/sys/block/bcache0/bcache# cat writeback_running
1
/sys/block/bcache0/bcache# cat writeback_rate_debug
rate:		512.0k/sec
dirty:		0.0k
target:		0.0k
proportional:	0.0k
integral:	0.0k
change:		0.0k/sec
next io:	-15427384ms

The none ZERO fields are misleading as no alive writeback kthread yet.

Set dc->writeback_running false as no writeback thread created in
bch_cached_dev_writeback_init().

We have writeback thread created and woken up in bch_cached_dev_writeback
_start(). Set dc->writeback_running true before bch_writeback_queue()
called, as a writeback thread will check if dc->writeback_running is true
before writing back dirty data, and hung if false detected.

After the change, we can get the following output for a fresh standalone
backing device:
-----------------------
/sys/block/bcache0/bcache$ cat writeback_running
0
/sys/block/bcache0/bcache# cat writeback_rate_debug
rate:		0.0k/sec
dirty:		0.0k
target:		0.0k
proportional:	0.0k
integral:	0.0k
change:		0.0k/sec
next io:	0ms

v1 -> v2:
  Set dc->writeback_running before bch_writeback_queue() called,

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Shenghui Wang 4e361e020e bcache: update comment in sysfs.c
We have struct cached_dev allocated by kzalloc in register_bcache(),
which initializes all the fields of cached_dev with 0s. And commit
ce4c3e19e5 ("bcache: Replace bch_read_string_list() by
__sysfs_match_string()") has remove the string "default".

Update the comment.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Shenghui Wang 3db4d0783e bcache: update comment for bch_data_insert
commit 220bb38c21 ("bcache: Break up struct search") introduced
changes to struct search and s->iop. bypass/bio are fields of struct
data_insert_op now. Update the comment.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Shenghui Wang ae17102316 bcache: do not check if debug dentry is ERR or NULL explicitly on remove
debugfs_remove and debugfs_remove_recursive will check if the dentry
pointer is NULL or ERR, and will do nothing in that case.

Remove the check in cache_set_free and bch_debug_init.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Shenghui Wang d2f96f487f bcache: add comment for cache_set->fill_iter
We have the following define for btree iterator:
	struct btree_iter {
		size_t size, used;
	#ifdef CONFIG_BCACHE_DEBUG
		struct btree_keys *b;
	#endif
		struct btree_iter_set {
			struct bkey *k, *end;
		} data[MAX_BSETS];
	};

We can see that the length of data[] field is static MAX_BSETS, which is
defined as 4 currently.

But a btree node on disk could have too many bsets for an iterator to fit
on the stack - maybe far more that MAX_BSETS. Have to dynamically allocate
space to host more btree_iter_sets.

bch_cache_set_alloc() will make sure the pool cache_set->fill_iter can
allocate an iterator equipped with enough room that can host
	(sb.bucket_size / sb.block_size)
btree_iter_sets, which is more than static MAX_BSETS.

bch_btree_node_read_done() will use that pool to allocate one iterator, to
host many bsets in one btree node.

Add more comment around cache_set->fill_iter to make code less confusing.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Dongbo Cao 3a646fd776 bcache: panic fix for making cache device
when the nbuckets of cache device is smaller than 1024, making cache
device will trigger BUG_ON in kernel, add a condition to avoid this.

Reported-by: nitroxis <n@nxs.re>
Signed-off-by: Dongbo Cao <cdbdyx@163.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:59 -06:00
Dongbo Cao f6027bca9e bcache: split combined if-condition code into separate ones
Split the combined '||' statements in if() check, to make the code easier
for debug.

Signed-off-by: Dongbo Cao <cdbdyx@163.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:57 -06:00
Shenghui Wang 8792099f9a bcache: use MAX_CACHES_PER_SET instead of magic number 8 in __bch_bucket_alloc_set
Current cache_set has MAX_CACHES_PER_SET caches most, and the macro
is used for
"
	struct cache *cache_by_alloc[MAX_CACHES_PER_SET];
"
in the define of struct cache_set.

Use MAX_CACHES_PER_SET instead of magic number 8 in
__bch_bucket_alloc_set.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:56 -06:00
Coly Li 149d0efada bcache: replace hard coded number with BUCKET_GC_GEN_MAX
In extents.c:bch_extent_bad(), number 96 is used as parameter to call
btree_bug_on(). The purpose is to check whether stale gen value exceeds
BUCKET_GC_GEN_MAX, so it is better to use macro BUCKET_GC_GEN_MAX to
make the code more understandable.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:55 -06:00
Dongbo Cao 91bafdf081 bcache: remove useless parameter of bch_debug_init()
Parameter "struct kobject *kobj" in bch_debug_init() is useless,
remove it in this patch.

Signed-off-by: Dongbo Cao <cdbdyx@163.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:53 -06:00
Shenghui Wang 3fd3c5c02b bcache: remove unused bch_passthrough_cache
struct kmem_cache *bch_passthrough_cache is not used in
bcache code. Remove it.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:52 -06:00
Shenghui Wang 46010141da bcache: recal cached_dev_sectors on detach
Recal cached_dev_sectors on cached_dev detached, as recal done on
cached_dev attached.

Update the cached_dev_sectors before bcache_device_detach called
as bcache_device_detach will set bcache_device->c to NULL.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:50 -06:00
Tang Junhui 2d6cb6edd2 bcache: fix miss key refill->end in writeback
refill->end record the last key of writeback, for example, at the first
time, keys (1,128K) to (1,1024K) are flush to the backend device, but
the end key (1,1024K) is not included, since the bellow code:
	if (bkey_cmp(k, refill->end) >= 0) {
		ret = MAP_DONE;
		goto out;
	}
And in the next time when we refill writeback keybuf again, we searched
key start from (1,1024K), and got a key bigger than it, so the key
(1,1024K) missed.
This patch modify the above code, and let the end key to be included to
the writeback key buffer.

Signed-off-by: Tang Junhui <tang.junhui.linux@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:48 -06:00
Ben Peddell 7567c2a2ad bcache: Populate writeback_rate_minimum attribute
Forgot to include the maintainers with my first email.

Somewhere between Michael Lyle's original
"bcache: PI controller for writeback rate V2" patch dated 07 Sep 2017
and 1d316e6 bcache: implement PI controller for writeback rate,
the mapping of the writeback_rate_minimum attribute was dropped.

Re-add the missing sysfs writeback_rate_minimum attribute mapping to
"allow the user to specify a minimum rate at which dirty blocks are
retired."

Fixes: 1d316e6 ("bcache: implement PI controller for writeback rate")
Signed-off-by: Ben Peddell <klightspeed@killerwolves.net>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:46 -06:00
Tang Junhui 2e17a262a2 bcache: correct dirty data statistics
When bcache device is clean, dirty keys may still exist after
journal replay, so we need to count these dirty keys even
device in clean status, otherwise after writeback, the amount
of dirty data would be incorrect.

Signed-off-by: Tang Junhui <tang.junhui.linux@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:45 -06:00
Coly Li 4516da427f bcache: fix typo in code comments of closure_return_with_destructor()
The code comments of closure_return_with_destructor() in closure.h makrs
function name as closure_return(). This patch fixes this type with the
correct name - closure_return_with_destructor.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:43 -06:00
Tang Junhui dd0c91793b bcache: fix ioctl in flash device
When doing ioctl in flash device, it will call ioctl_dev() in super.c,
then we should not to get cached device since flash only device has
no backend device. This patch just move the jugement dc->io_disable
to cached_dev_ioctl() to make ioctl in flash device correctly.

Fixes: 0f0709e6bf ("bcache: stop bcache device when backing device is offline")
Signed-off-by: Tang Junhui <tang.junhui.linux@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:42 -06:00
Coly Li 752f66a75a bcache: use REQ_PRIO to indicate bio for metadata
In cached_dev_cache_miss() and check_should_bypass(), REQ_META is used
to check whether a bio is for metadata request. REQ_META is used for
blktrace, the correct REQ_ flag should be REQ_PRIO. This flag means the
bio should be prior to other bio, and frequently be used to indicate
metadata io in file system code.

This patch replaces REQ_META with correct flag REQ_PRIO.

CC Adam Manzanares because he explains to me what REQ_PRIO is for.

Signed-off-by: Coly Li <colyli@suse.de>
Cc: Adam Manzanares <adam.manzanares@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:40 -06:00
Tang Junhui 502b291568 bcache: trace missed reading by cache_missed
Missed reading IOs are identified by s->cache_missed, not the
s->cache_miss, so in trace_bcache_read() using trace_bcache_read
to identify whether the IO is missed or not.

Signed-off-by: Tang Junhui <tang.junhui.linux@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:39 -06:00
Shenghui Wang 7a55948d38 bcache: account size of buckets used in uuid write to ca->meta_sectors_written
UUIDs are considered as metadata. __uuid_write should add the number
of buckets (in sectors) written to disk to ca->meta_sectors_written.
Currently only 1 bucket is used in uuid write.

Steps to test:
1) create a fresh backing device and a fresh cache device separately.
   The backing device didn't attach to any cache set.
2) cd /sys/block/<cache device>/bcache
   cat metadata_written      // record the output value
   cat bucket_size
3) attach the backing device to cache set
4) cat metadata_written
   The output value is almost the same as the value in step 2
   before the change.
   After the change, the value is bigger about 1 bucket size.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Reviewed-by: Tang Junhui <tang.junhui.linux@gmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08 08:19:37 -06:00
Guoju Fang 0f843e65d9 bcache: add separate workqueue for journal_write to avoid deadlock
After write SSD completed, bcache schedules journal_write work to
system_wq, which is a public workqueue in system, without WQ_MEM_RECLAIM
flag. system_wq is also a bound wq, and there may be no idle kworker on
current processor. Creating a new kworker may unfortunately need to
reclaim memory first, by shrinking cache and slab used by vfs, which
depends on bcache device. That's a deadlock.

This patch create a new workqueue for journal_write with WQ_MEM_RECLAIM
flag. It's rescuer thread will work to avoid the deadlock.

Signed-off-by: Guoju Fang <fangguoju@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-27 09:47:01 -06:00
Shan Hai 3943b040f1 bcache: release dc->writeback_lock properly in bch_writeback_thread()
The writeback thread would exit with a lock held when the cache device
is detached via sysfs interface, fix it by releasing the held lock
before exiting the while-loop.

Fixes: fadd94e05c (bcache: quit dc->writeback_thread when BCACHE_DEV_DETACHING is set)
Signed-off-by: Shan Hai <shan.hai@oracle.com>
Signed-off-by: Coly Li <colyli@suse.de>
Tested-by: Shenghui Wang <shhuiw@foxmail.com>
Cc: stable@vger.kernel.org #4.17+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-22 15:06:29 -06:00
Linus Torvalds 5bed49adfe for-4.19/post-20180822
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Merge tag 'for-4.19/post-20180822' of git://git.kernel.dk/linux-block

Pull more block updates from Jens Axboe:

 - Set of bcache fixes and changes (Coly)

 - The flush warn fix (me)

 - Small series of BFQ fixes (Paolo)

 - wbt hang fix (Ming)

 - blktrace fix (Steven)

 - blk-mq hardware queue count update fix (Jianchao)

 - Various little fixes

* tag 'for-4.19/post-20180822' of git://git.kernel.dk/linux-block: (31 commits)
  block/DAC960.c: make some arrays static const, shrinks object size
  blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iter
  blk-mq: init hctx sched after update ctx and hctx mapping
  block: remove duplicate initialization
  tracing/blktrace: Fix to allow setting same value
  pktcdvd: fix setting of 'ret' error return for a few cases
  block: change return type to bool
  block, bfq: return nbytes and not zero from struct cftype .write() method
  block, bfq: improve code of bfq_bfqq_charge_time
  block, bfq: reduce write overcharge
  block, bfq: always update the budget of an entity when needed
  block, bfq: readd missing reset of parent-entity service
  blk-wbt: fix IO hang in wbt_wait()
  block: don't warn for flush on read-only device
  bcache: add the missing comments for smp_mb()/smp_wmb()
  bcache: remove unnecessary space before ioctl function pointer arguments
  bcache: add missing SPDX header
  bcache: move open brace at end of function definitions to next line
  bcache: add static const prefix to char * array declarations
  bcache: fix code comments style
  ...
2018-08-22 13:38:05 -07:00
Coly Li d23599630b bcache: use routines from lib/crc64.c for CRC64 calculation
Now we have crc64 calculation in lib/crc64.c, it is unnecessary for
bcache to use its own version.  This patch changes bcache code to use
crc64 routines in lib/crc64.c.

Link: http://lkml.kernel.org/r/20180718165545.1622-3-colyli@suse.de
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Michael Lyle <mlyle@lyle.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Noah Massey <noah.massey@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:48 -07:00
Coly Li eb2b3d0345 bcache: add the missing comments for smp_mb()/smp_wmb()
Checkpatch.pl warns there are 2 locations of smp_mb() and smp_wmb()
without code comment. This patch adds the missing code comments for
these memory barrier calls.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:42 -06:00
Coly Li d0c1b89a40 bcache: remove unnecessary space before ioctl function pointer arguments
This is warned by checkpatch.pl, this patch removes the extra space.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:42 -06:00
Coly Li 87418ef9f0 bcache: add missing SPDX header
The SPDX header is missing fro closure.c, super.c and util.c, this
patch adds SPDX header for GPL-2.0 into these files.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:42 -06:00
Coly Li b3cf37bfa1 bcache: move open brace at end of function definitions to next line
This is not a preferred style to place open brace '{' at the end of
function definition, checkpatch.pl reports error for such coding
style. This patch moves them into the start of the next new line.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:42 -06:00
Coly Li e1f08f1bc0 bcache: add static const prefix to char * array declarations
This patch declares char * array with const prefix in sysfs.c,
which is suggested by checkpatch.pl.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:42 -06:00
Coly Li 3be11dbab6 bcache: fix code comments style
This patch fixes 3 style issues warned by checkpatch.pl,
- Comment lines are not aligned
- Comments use "/*" on subsequent lines
- Comment lines use a trailing "*/"

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:42 -06:00
Coly Li 3069211be3 bcache: do not check NULL pointer before calling kmem_cache_destroy
kmem_cache_destroy() is safe for NULL pointer as input, the NULL pointer
checking is unncessary. This patch just removes the NULL pointer checking
to make code simpler.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:42 -06:00
Coly Li bc81b47e82 bcache: prefer 'help' in Kconfig
Current bcache Kconfig uses '---help---' as header of help information,
for now 'help' is prefered. This patch fixes this style by replacing
'---help---' by 'help' in bcache Kconfig file.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:42 -06:00
Coly Li 2b1edd23ec bcache: fix typo 'succesfully' to 'successfully'
This patch fixes typo 'succesfully' to correct 'successfully', which is
suggested by checkpatch.pl.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:42 -06:00
Coly Li d9c61d30e8 bcache: replace '%pF' by '%pS' in seq_printf()
'%pF' and '%pf' are deprecated vsprintf pointer extensions, this patch
replace them by '%pS', which is suggested by checkpatch.pl.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:41 -06:00
Coly Li c63ca7871a bcache: fix indent by replacing blank by tabs
bch_btree_insert_check_key() has unaligned indent, or indent by blank
characters. This patch makes the indent aligned and replace blank by
tabs.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:41 -06:00
Coly Li 6ae63e3501 bcache: replace printk() by pr_*() routines
There are still many places in bcache use printk to display kernel
message, which are suggested to be preplaced by pr_*() routines like
pr_err(), pr_info(), or pr_notice().

This patch replaces all printk() with a proper pr_*() routine for
bcache code.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:41 -06:00
Coly Li 958bf494ec bcache: replace Symbolic permissions by octal permission numbers
Symbolic permission names are used in bcache, for now octal permission
numbers are encouraged to use for readability. This patch replaces
all symbolic permissions by octal permission numbers.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:41 -06:00
Coly Li b0d30981c0 bcache: style fixes for lines over 80 characters
This patch fixes the lines over 80 characters into more lines, to minimize
warnings by checkpatch.pl. There are still some lines exceed 80 characters,
but it is better to be a single line and I don't change them.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:41 -06:00
Coly Li fc2d5988b5 bcache: add identifier names to arguments of function definitions
There are many function definitions do not have identifier argument names,
scripts/checkpatch.pl complains warnings like this,

 WARNING: function definition argument 'struct bcache_device *' should
  also have an identifier name
  #16735: FILE: writeback.h:120:
  +void bch_sectors_dirty_init(struct bcache_device *);

This patch adds identifier argument names to all bcache function
definitions to fix such warnings.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:41 -06:00
Coly Li 1fae7cf052 bcache: style fix to add a blank line after declarations
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:41 -06:00
Coly Li 6f10f7d1b0 bcache: style fix to replace 'unsigned' by 'unsigned int'
This patch fixes warning reported by checkpatch.pl by replacing 'unsigned'
with 'unsigned int'.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-11 15:46:41 -06:00
Coly Li 46451874c7 bcache: fix error setting writeback_rate through sysfs interface
Commit ea8c5356d3 ("bcache: set max writeback rate when I/O request
is idle") changes struct bch_ratelimit member rate from uint32_t to
atomic_long_t and uses atomic_long_set() in drivers/md/bcache/sysfs.c
to set new writeback rate, after the input is converted from memory
buf to long int by sysfs_strtoul_clamp().

The above change has a problem because there is an implicit return
inside sysfs_strtoul_clamp() so the following atomic_long_set()
won't be called. This error is detected by 0day system with following
snipped smatch warnings:

drivers/md/bcache/sysfs.c:271 __cached_dev_store() error: uninitialized
symbol 'v'.
270  sysfs_strtoul_clamp(writeback_rate, v, 1, INT_MAX);
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@271 atomic_long_set(&dc->writeback_rate.rate, v);

This patch fixes the above error by using strtoul_safe_clamp() to
convert the input buffer into a long int type result.

Fixes: ea8c5356d3 ("bcache: set max writeback rate when I/O request is idle")
Cc: Kai Krakow <kai@kaishome.de>
Cc: Stefan Priebe <s.priebe@profihost.ag>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-10 12:18:47 -06:00
Shenghui Wang cbb751c060 bcache: trivial - remove tailing backslash in macro BTREE_FLAG
Remove the tailing backslash in macro BTREE_FLAG in btree.h

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-09 08:21:19 -06:00
Shenghui Wang e921efeb07 bcache: make the pr_err statement used for ENOENT only in sysfs_attatch section
The pr_err statement in the code for sysfs_attatch section would run
for various error codes, which maybe confusing.

E.g,

Run the command twice:
   echo 796b5c05-b03c-4bc7-9cbd-a8df5e8be891 > \
				/sys/block/bcache0/bcache/attach
   [the backing dev got attached on the first run]
   echo 796b5c05-b03c-4bc7-9cbd-a8df5e8be891 > \
				/sys/block/bcache0/bcache/attach

In dmesg, after the command run twice, we can get:
	bcache: bch_cached_dev_attach() Can't attach sda6: already attached
	bcache: __cached_dev_store() Can't attach 796b5c05-b03c-4bc7-9cbd-\
a8df5e8be891
               : cache set not found
The first statement in the message was right, but the second was
confusing.

bch_cached_dev_attach has various pr_ statements for various error
codes, except ENOENT.

After the change, rerun above command twice:
	echo 796b5c05-b03c-4bc7-9cbd-a8df5e8be891 > \
			/sys/block/bcache0/bcache/attach
	echo 796b5c05-b03c-4bc7-9cbd-a8df5e8be891 > \
			/sys/block/bcache0/bcache/attach

In dmesg we only got:
	bcache: bch_cached_dev_attach() Can't attach sda6: already attached
No confusing "cache set not found" message anymore.

And for some not exist SET-UUID:
	echo 796b5c05-b03c-4bc7-9cbd-a8df5e8be898 > \
			/sys/block/bcache0/bcache/attach
In dmesg we can get:
	bcache: __cached_dev_store() Can't attach 796b5c05-b03c-4bc7-9cbd-\
a8df5e8be898
	               : cache set not found

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-09 08:21:17 -06:00
Coly Li ea8c5356d3 bcache: set max writeback rate when I/O request is idle
Commit b1092c9af9 ("bcache: allow quick writeback when backing idle")
allows the writeback rate to be faster if there is no I/O request on a
bcache device. It works well if there is only one bcache device attached
to the cache set. If there are many bcache devices attached to a cache
set, it may introduce performance regression because multiple faster
writeback threads of the idle bcache devices will compete the btree level
locks with the bcache device who have I/O requests coming.

This patch fixes the above issue by only permitting fast writebac when
all bcache devices attached on the cache set are idle. And if one of the
bcache devices has new I/O request coming, minimized all writeback
throughput immediately and let PI controller __update_writeback_rate()
to decide the upcoming writeback rate for each bcache device.

Also when all bcache devices are idle, limited wrieback rate to a small
number is wast of thoughput, especially when backing devices are slower
non-rotation devices (e.g. SATA SSD). This patch sets a max writeback
rate for each backing device if the whole cache set is idle. A faster
writeback rate in idle time means new I/Os may have more available space
for dirty data, and people may observe a better write performance then.

Please note bcache may change its cache mode in run time, and this patch
still works if the cache mode is switched from writeback mode and there
is still dirty data on cache.

Fixes: Commit b1092c9af9 ("bcache: allow quick writeback when backing idle")
Cc: stable@vger.kernel.org #4.16+
Signed-off-by: Coly Li <colyli@suse.de>
Tested-by: Kai Krakow <kai@kaishome.de>
Tested-by: Stefan Priebe <s.priebe@profihost.ag>
Cc: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-09 08:21:15 -06:00
Coly Li b467a6ac0b bcache: add code comments for bset.c
This patch tries to add code comments in bset.c, to make some
tricky code and designment to be more comprehensible. Most information
of this patch comes from the discussion between Kent and I, he
offers very informative details. If there is any mistake
of the idea behind the code, no doubt that's from me misrepresentation.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-09 08:21:12 -06:00
Coly Li 0cba2e7111 bcache: fix mistaken comments in request.c
This patch updates code comment in bch_keylist_realloc() by fixing
incorrected function names, to make the code to be more comprehennsible.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-09 08:21:10 -06:00
Coly Li cb329dec11 bcache: fix mistaken code comments in bcache.h
This patch updates the code comment in struct cache with correct array
names, to make the code to be more comprehensible.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-09 08:21:09 -06:00
Coly Li e57fd74684 bcache: add a comment in super.c
This patch adds a line of code comment in super.c:register_bdev(), to
make code to be more comprehensible.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-09 08:21:07 -06:00
Coly Li c2e8dcf7fa bcache: avoid unncessary cache prefetch bch_btree_node_get()
In bch_btree_node_get() the read-in btree node will be partially
prefetched into L1 cache for following bset iteration (if there is).
But if the btree node read is failed, the perfetch operations will
waste L1 cache space. This patch checkes whether read operation and
only does cache prefetch when read I/O succeeded.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-09 08:21:05 -06:00
Coly Li b4cb6efc1a bcache: display rate debug parameters to 0 when writeback is not running
When writeback is not running, writeback rate should be 0, other value is
misleading. And the following dyanmic writeback rate debug parameters
should be 0 too,
	rate, proportional, integral, change
otherwise they are misleading when writeback is not running.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-09 08:21:03 -06:00