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  1. 06 9月, 2017 10 次提交
    • D
      bcache: silence static checker warning · da22f0ee
      由 Dan Carpenter 提交于 
      In olden times, closure_return() used to have a hidden return built in.
We removed the hidden return but forgot to add a new return here.  If
"c" were NULL we would oops on the next line, but fortunately "c" is
never NULL.  Let's just remove the if statement.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      da22f0ee
    • T
      bcache: fix for gc and write-back race · 9baf3097
      由 Tang Junhui 提交于 
      gc and write-back get raced (see the email "bcache get stucked" I sended
before):
gc thread                               write-back thread
|                                       |bch_writeback_thread()
|bch_gc_thread()                        |
|                                       |==>read_dirty()
|==>bch_btree_gc()                      |
|==>btree_root() //get btree root       |
|                //node write locker    |
|==>bch_btree_gc_root()                 |
|                                       |==>read_dirty_submit()
|                                       |==>write_dirty()
|                                       |==>continue_at(cl,
|                                       |               write_dirty_finish,
|                                       |               system_wq);
|                                       |==>write_dirty_finish()//excute
|                                       |               //in system_wq
|                                       |==>bch_btree_insert()
|                                       |==>bch_btree_map_leaf_nodes()
|                                       |==>__bch_btree_map_nodes()
|                                       |==>btree_root //try to get btree
|                                       |              //root node read
|                                       |              //lock
|                                       |-----stuck here
|==>bch_btree_set_root()
|==>bch_journal_meta()
|==>bch_journal()
|==>journal_try_write()
|==>journal_write_unlocked() //journal_full(&c->journal)
|                            //condition satisfied
|==>continue_at(cl, journal_write, system_wq); //try to excute
|                               //journal_write in system_wq
|                               //but work queue is excuting
|                               //write_dirty_finish()
|==>closure_sync(); //wait journal_write execute
|                   //over and wake up gc,
|-------------stuck here
|==>release root node write locker

This patch alloc a separate work-queue for write-back thread to avoid such
race.

(Commit log re-organized by Coly Li to pass checkpatch.pl checking)
Signed-off-by: NTang Junhui <tang.junhui@zte.com.cn>
Acked-by: NColy Li <colyli@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      9baf3097
    • T
      bcache: increase the number of open buckets · 89b1fc54
      由 Tang Junhui 提交于 
      In currently, we only alloc 6 open buckets for each cache set,
but in usually, we always attach about 10 or so backend devices for
each cache set, and the each bcache device are always accessed by
about 10 or so threads in top application layer. So 6 open buckets
are too few, It has led to that each of the same thread write data
to different buckets, which would cause low efficiency write-back,
and also cause buckets inefficient, and would be Very easy to run
out of.

I add debug message in bch_open_buckets_alloc() to print alloc bucket
info, and test with ten bcache devices with a cache set, and each
bcache device is accessed by ten threads.

From the debug message, we can see that, after the modification, One
bucket is more likely to assign to the same thread, and the data from
the same thread are more likely to write the same bucket. Usually the
same thread always write/read the same backend device, so it is good
for write-back and also promote the usage efficiency of buckets.
Signed-off-by: NTang Junhui <tang.junhui@zte.com.cn>
Reviewed-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      89b1fc54
    • T
      bcache: Correct return value for sysfs attach errors · 77fa100f
      由 Tony Asleson 提交于 
      If you encounter any errors in bch_cached_dev_attach it will return
a negative error code.  The variable 'v' which stores the result is
unsigned, thus user space sees a very large value returned for bytes
written which can cause incorrect user space behavior.  Utilize 1
signed variable to use throughout the function to preserve error return
capability.
Signed-off-by: NTony Asleson <tasleson@redhat.com>
Acked-by: NColy Li <colyli@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      77fa100f
    • T
      bcache: correct cache_dirty_target in __update_writeback_rate() · a8394090
      由 Tang Junhui 提交于 
      __update_write_rate() uses a Proportion-Differentiation Controller
algorithm to control writeback rate. A dirty target number is used in
this PD controller to control writeback rate. A larger target number
will make the writeback rate smaller, on the versus, a smaller target
number will make the writeback rate larger.

bcache uses the following steps to calculate the target number,
1) cache_sectors = all-buckets-of-cache-set * buckets-size
2) cache_dirty_target = cache_sectors * cached-device-writeback_percent
3) target = cache_dirty_target *
(sectors-of-cached-device/sectors-of-all-cached-devices-of-this-cache-set)

The calculation at step 1) for cache_sectors is incorrect, which does
not consider dirty blocks occupied by flash only volume.

A flash only volume can be took as a bcache device without cached
device. All data sectors allocated for it are persistent on cache device
and marked dirty, they are not touched by bcache writeback and garbage
collection code. So data blocks of flash only volume should be ignore
when calculating cache_sectors of cache set.

Current code does not subtract dirty sectors of flash only volume, which
results a larger target number from the above 3 steps. And in sequence
the cache device's writeback rate is smaller then a correct value,
writeback speed is slower on all cached devices.

This patch fixes the incorrect slower writeback rate by subtracting
dirty sectors of flash only volumes in __update_writeback_rate().

(Commit log composed by Coly Li to pass checkpatch.pl checking)
Signed-off-by: NTang Junhui <tang.junhui@zte.com.cn>
Reviewed-by: NColy Li <colyli@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      a8394090
    • T
      bcache: gc does not work when triggering by manual command · 0b43f49d
      由 Tang Junhui 提交于 
      I try to execute the following command to trigger gc thread:
[root@localhost internal]# echo 1 > trigger_gc
But it does not work, I debug the code in gc_should_run(), It works only
if in invalidating or sectors_to_gc < 0. So set sectors_to_gc to -1 to
meet the condition when we trigger gc by manual command.

(Code comments aded by Coly Li)
Signed-off-by: NTang Junhui <tang.junhui@zte.com.cn>
Reviewed-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      0b43f49d
    • B
      bcache: Don't reinvent the wheel but use existing llist API · 09b3efec
      由 Byungchul Park 提交于 
      Although llist provides proper APIs, they are not used. Make them used.
Signed-off-by: NByungchul Park <byungchul.park@lge.com>
Acked-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      09b3efec
    • T
      bcache: do not subtract sectors_to_gc for bypassed IO · 69daf03a
      由 Tang Junhui 提交于 
      Since bypassed IOs use no bucket, so do not subtract sectors_to_gc to
trigger gc thread.
Signed-off-by: Ntang.junhui <tang.junhui@zte.com.cn>
Acked-by: NColy Li <colyli@suse.de>
Reviewed-by: NEric Wheeler <bcache@linux.ewheeler.net>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      69daf03a
    • T
      bcache: fix sequential large write IO bypass · c81ffa32
      由 Tang Junhui 提交于 
      Sequential write IOs were tested with bs=1M by FIO in writeback cache
mode, these IOs were expected to be bypassed, but actually they did not.
We debug the code, and find in check_should_bypass():
    if (!congested &&
        mode == CACHE_MODE_WRITEBACK &&
        op_is_write(bio_op(bio)) &&
        (bio-＞bi_opf & REQ_SYNC))
        goto rescale
that means, If in writeback mode, a write IO with REQ_SYNC flag will not
be bypassed though it is a sequential large IO, It's not a correct thing
to do actually, so this patch remove these codes.
Signed-off-by: Ntang.junhui <tang.junhui@zte.com.cn>
Reviewed-by: NKent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: NEric Wheeler <bcache@linux.ewheeler.net>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      c81ffa32
    • J
      bcache: Fix leak of bdev reference · 4b758df2
      由 Jan Kara 提交于 
      If blkdev_get_by_path() in register_bcache() fails, we try to lookup the
block device using lookup_bdev() to detect which situation we are in to
properly report error. However we never drop the reference returned to
us from lookup_bdev(). Fix that.
Signed-off-by: NJan Kara <jack@suse.cz>
Acked-by: NColy Li <colyli@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      4b758df2
  3. 24 8月, 2017 2 次提交
    • C
      block: replace bi_bdev with a gendisk pointer and partitions index · 74d46992
      由 Christoph Hellwig 提交于 
      This way we don't need a block_device structure to submit I/O.  The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open.  Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).

For the actual I/O path all that we need is the gendisk, which exists
once per block device.  But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.

Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      74d46992
    • C
      raid5: remove a call to get_start_sect · 10433d04
      由 Christoph Hellwig 提交于 
      The block layer always remaps partitions before calling into the
->make_request methods of drivers.  Thus the call to get_start_sect in
in_chunk_boundary will always return 0 and can be removed.
Reviewed-by: NShaohua Li <shli@fb.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      10433d04
  5. 12 8月, 2017 1 次提交
  7. 10 8月, 2017 2 次提交
  9. 08 8月, 2017 4 次提交
    • S
      md/r5cache: fix io_unit handling in r5l_log_endio() · a9501d74
      由 Song Liu 提交于 
      In r5l_log_endio(), once log->io_list_lock is released, the io unit
may be accessed (or even freed) by other threads. Current code
doesn't handle the io_unit properly, which leads to potential race
conditions.

This patch solves this race condition by:

1. Add a pending_stripe count flush_payload. Multiple flush_payloads
   are counted as only one pending_stripe. Flag has_flush_payload is
   added to show whether the io unit has flush_payload;
2. In r5l_log_endio(), check flags has_null_flush and
   has_flush_payload with log->io_list_lock held. After the lock
   is released, this IO unit is only accessed when we know the
   pending_stripe counter cannot be zeroed by other threads.
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NShaohua Li <shli@fb.com>
      a9501d74
    • S
      md/r5cache: call mddev_lock/unlock() in r5c_journal_mode_set · b44886c5
      由 Song Liu 提交于 
      In r5c_journal_mode_set(), it is necessary to call mddev_lock()
before accessing conf and conf->log. Otherwise, the conf->log
may change (and become NULL).

Shaohua: fix unlock in failure cases
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NShaohua Li <shli@fb.com>
      b44886c5
    • N
      md: fix test in md_write_start() · 81fe48e9
      由 NeilBrown 提交于 
      md_write_start() needs to clear the in_sync flag is it is set, or if
there might be a race with set_in_sync() such that the later will
set it very soon.  In the later case it is sufficient to take the
spinlock to synchronize with set_in_sync(), and then set the flag
if needed.

The current test is incorrect.
It should be:
  if "flag is set" or "race is possible"

"flag is set" is trivially "mddev->in_sync".
"race is possible" should be tested by "mddev->sync_checkers".

If sync_checkers is 0, then there can be no race.  set_in_sync() will
wait in percpu_ref_switch_to_atomic_sync() for an RCU grace period,
and as md_write_start() holds the rcu_read_lock(), set_in_sync() will
be sure ot see the update to writes_pending.

If sync_checkers is > 0, there could be race.  If md_write_start()
happened entirely between
		if (!mddev->in_sync &&
		    percpu_ref_is_zero(&mddev->writes_pending)) {
and
			mddev->in_sync = 1;
in set_in_sync(), then it would not see that is_sync had been set,
and set_in_sync() would not see that writes_pending had been
incremented.

This bug means that in_sync is sometimes not set when it should be.
Consequently there is a small chance that the array will be marked as
"clean" when in fact it is inconsistent.

Fixes: 4ad23a97 ("MD: use per-cpu counter for writes_pending")
cc: stable@vger.kernel.org (v4.12+)
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>
      81fe48e9
    • N
      md: always clear ->safemode when md_check_recovery gets the mddev lock. · 33182d15
      由 NeilBrown 提交于 
      If ->safemode == 1, md_check_recovery() will try to get the mddev lock
and perform various other checks.
If mddev->in_sync is zero, it will call set_in_sync, and clear
->safemode.  However if mddev->in_sync is not zero, ->safemode will not
be cleared.

When md_check_recovery() drops the mddev lock, the thread is woken
up again.  Normally it would just check if there was anything else to
do, find nothing, and go to sleep.  However as ->safemode was not
cleared, it will take the mddev lock again, then wake itself up
when unlocking.

This results in an infinite loop, repeatedly calling
md_check_recovery(), which RCU or the soft-lockup detector
will eventually complain about.

Prior to commit 4ad23a97 ("MD: use per-cpu counter for
writes_pending"), safemode would only be set to one when the
writes_pending counter reached zero, and would be cleared again
when writes_pending is incremented.  Since that patch, safemode
is set more freely, but is not reliably cleared.

So in md_check_recovery() clear ->safemode before checking ->in_sync.

Fixes: 4ad23a97 ("MD: use per-cpu counter for writes_pending")
Cc: stable@vger.kernel.org (4.12+)
Reported-by: NDominik Brodowski <linux@dominikbrodowski.net>
Reported-by: NDavid R <david@unsolicited.net>
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>
      33182d15
  11. 27 7月, 2017 3 次提交
  13. 26 7月, 2017 6 次提交
  15. 25 7月, 2017 3 次提交
  17. 24 7月, 2017 1 次提交
  19. 22 7月, 2017 5 次提交
  21. 20 7月, 2017 2 次提交
  23. 13 7月, 2017 1 次提交