linux-toradex.git/drivers/md/bcache/super.c, branch v4.9.60

bcache: fix for gc and write-back race

2017-09-27T12:39:25+00:00

commit 9baf30972b5568d8b5bc8b3c46a6ec5b58100463 upstream.

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: Tang Junhui 
Acked-by: Coly Li 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: Fix leak of bdev reference

2017-09-27T12:39:24+00:00

commit 4b758df21ee7081ab41448d21d60367efaa625b3 upstream.

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: Jan Kara 
Acked-by: Coly Li 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: initialize dirty stripes in flash_dev_run()

2017-09-27T12:39:24+00:00

commit 175206cf9ab63161dec74d9cd7f9992e062491f5 upstream.

bcache uses a Proportion-Differentiation Controller algorithm to control
writeback rate to cached devices. In the PD controller algorithm, dirty
stripes of thin flash device should not be counted in, because flash only
volumes never write back dirty data.

Currently dirty stripe counter for thin flash device is not initialized
when the thin flash device starts. Which means the following calculation
in PD controller will reference an undefined dirty stripes number, and
all cached devices attached to the same cache set where the thin flash
device lies on may have an inaccurate writeback rate.

This patch calles bch_sectors_dirty_init() in flash_dev_run(), to
correctly initialize dirty stripe counter when the thin flash device
starts to run. This patch also does following parameter data type change,
 -void bch_sectors_dirty_init(struct cached_dev *dc);
 +void bch_sectors_dirty_init(struct bcache_device *);
to call this function conveniently in flash_dev_run().

(Commit log is composed by Coly Li)

Signed-off-by: Tang Junhui 
Reviewed-by: Coly Li 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: Make gc wakeup sane, remove set_task_state()

2017-02-23T16:44:36+00:00

commit be628be09563f8f6e81929efbd7cf3f45c344416 upstream.

Signed-off-by: Kent Overstreet 
Cc: Coly Li 
Signed-off-by: Greg Kroah-Hartman

bcache: pr_err: more meaningful error message when nr_stripes is invalid

2016-08-19T03:31:03+00:00

The original error was thought to be corruption, but was actually caused by:
	make-bcache --data-offset N
where N was in bytes and should have been in sectors.  While userspace
tools should be updated to check --data-offset beyond end of volume,
hopefully this will help others that might not have noticed the units.

Signed-off-by: Eric Wheeler 
Cc: Kent Overstreet

bcache: RESERVE_PRIO is too small by one when prio_buckets() is a power of two.

2016-08-19T03:29:49+00:00

This patch fixes a cachedev registration-time allocation deadlock.
This can deadlock on boot if your initrd auto-registeres bcache devices:

Allocator thread:
[  720.727614] INFO: task bcache_allocato:3833 blocked for more than 120 seconds.
[  720.732361]  [] schedule+0x37/0x90
[  720.732963]  [] bch_bucket_alloc+0x188/0x360 [bcache]
[  720.733538]  [] ? prepare_to_wait_event+0xf0/0xf0
[  720.734137]  [] bch_prio_write+0x19d/0x340 [bcache]
[  720.734715]  [] bch_allocator_thread+0x3ff/0x470 [bcache]
[  720.735311]  [] ? __schedule+0x2dc/0x950
[  720.735884]  [] ? invalidate_buckets+0x980/0x980 [bcache]

Registration thread:
[  720.710403] INFO: task bash:3531 blocked for more than 120 seconds.
[  720.715226]  [] schedule+0x37/0x90
[  720.715805]  [] __bch_btree_map_nodes+0x12d/0x150 [bcache]
[  720.716409]  [] ? bch_btree_insert_check_key+0x1c0/0x1c0 [bcache]
[  720.717008]  [] bch_btree_insert+0xf4/0x170 [bcache]
[  720.717586]  [] ? prepare_to_wait_event+0xf0/0xf0
[  720.718191]  [] bch_journal_replay+0x14a/0x290 [bcache]
[  720.718766]  [] ? ttwu_do_activate.constprop.94+0x5d/0x70
[  720.719369]  [] ? try_to_wake_up+0x1d4/0x350
[  720.719968]  [] run_cache_set+0x580/0x8e0 [bcache]
[  720.720553]  [] register_bcache+0xe2e/0x13b0 [bcache]
[  720.721153]  [] kobj_attr_store+0xf/0x20
[  720.721730]  [] sysfs_kf_write+0x3d/0x50
[  720.722327]  [] kernfs_fop_write+0x12a/0x180
[  720.722904]  [] __vfs_write+0x37/0x110
[  720.723503]  [] ? __sb_start_write+0x58/0x110
[  720.724100]  [] ? security_file_permission+0x23/0xa0
[  720.724675]  [] vfs_write+0xa9/0x1b0
[  720.725275]  [] ? do_audit_syscall_entry+0x6c/0x70
[  720.725849]  [] SyS_write+0x55/0xd0
[  720.726451]  [] ? do_page_fault+0x30/0x80
[  720.727045]  [] system_call_fastpath+0x12/0x71

The fifo code in upstream bcache can't use the last element in the buffer,
which was the cause of the bug: if you asked for a power of two size,
it'd give you a fifo that could hold one less than what you asked for
rather than allocating a buffer twice as big.

Signed-off-by: Kent Overstreet 
Tested-by: Eric Wheeler 
Cc: stable@vger.kernel.org

bcache: register_bcache(): call blkdev_put() when cache_alloc() fails

2016-08-19T03:28:23+00:00

register_cache() is supposed to return an error string on error so that
register_bcache() will will blkdev_put and cleanup other user counters,
but it does not set 'char *err' when cache_alloc() fails (eg, due to
memory pressure) and thus register_bcache() performs no cleanup.

register_bcache() <----------\  <- no jump to err_close, no blkdev_put()
   |                         |
   +->register_cache()       |  <- fails to set char *err
         |                   |
         +->cache_alloc() ---/  <- returns error

This patch sets `char *err` for this failure case so that register_cache()
will cause register_bcache() to correctly jump to err_close and do
cleanup.  This was tested under OOM conditions that triggered the bug.

Signed-off-by: Eric Wheeler 
Cc: Kent Overstreet 
Cc: stable@vger.kernel.org

block: rename bio bi_rw to bi_opf

2016-08-07T20:41:02+00:00

Since commit 63a4cc24867d, bio->bi_rw contains flags in the lower
portion and the op code in the higher portions. This means that
old code that relies on manually setting bi_rw is most likely
going to be broken. Instead of letting that brokeness linger,
rename the member, to force old and out-of-tree code to break
at compile time instead of at runtime.

No intended functional changes in this commit.

Signed-off-by: Jens Axboe

bcache: Remove redundant block_size assignment

2016-07-05T17:34:50+00:00

We have assigned sb->block_size before the switch,
so remove the redundant one.

Reviewed-by: Coly Li 
Signed-off-by: Yijing Wang 
Acked-by: Eric Wheeler 
Signed-off-by: Jens Axboe

bcache: Remove redundant parameter for cache_alloc()

2016-07-05T17:34:47+00:00

Cache_sb is not used in cache_alloc, and we have copied
sb info to cache->sb already, remove it.

Reviewed-by: Coly Li 
Signed-off-by: Yijing Wang 
Signed-off-by: Jens Axboe