When gc is running, user space I/O processes may wait inside
bcache code, so no new I/O coming. Indeed this is not a real idle
time, maximum writeback rate should not be set in such situation.
Otherwise a faster writeback thread may compete locks with gc thread
and makes garbage collection slower, which results a longer I/O
freeze period.
This patch checks c->gc_mark_valid in set_at_max_writeback_rate(). If
c->gc_mark_valid is 0 (gc running), set_at_max_writeback_rate() returns
false, then update_writeback_rate() will not set writeback rate to
maximum value even c->idle_counter reaches an idle threshold.
Now writeback thread won't interfere gc thread performance.
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When people set a writeback percent via sysfs file,
/sys/block/bcache<N>/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 3fd47bfe55 ("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: 3fd47bfe55 ("bcache: stop dc->writeback_rate_update properly")
Reported-by: Bjørn Forsman <bjorn.forsman@gmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Bjørn Forsman <bjorn.forsman@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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: 0eacac2203 ("bcache: PRECEDING_KEY()")
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Rolf Fokkens <rolf@rolffokkens.nl>
Reviewed-by: Pierre JUHEN <pierre.juhen@orange.fr>
Tested-by: Shenghui Wang <shhuiw@foxmail.com>
Tested-by: Pierre JUHEN <pierre.juhen@orange.fr>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Nix <nix@esperi.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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 <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
'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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
