Instead we use standard iterator way to do that.
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Some drivers often use external bvec table, so introduce
this helper for this case. It is always safe to access the
bio->bi_io_vec in this way for this case.

After converting to this usage, it will becomes a bit easier
to evaluate the remaining direct access to bio->bi_io_vec,
so it can help to prepare for the following multipage bvec
support.
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

Fixed up the new O_DIRECT cases.
Signed-off-by: NJens Axboe <axboe@fb.com>

Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly.  Where applicable this also drops usage of the
bio_set_op_attrs wrapper.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

(and remove one layer of masking for the op_is_write call next to it).
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

bio_free_pages is introduced in commit 1dfa0f68
("block: add a helper to free bio bounce buffer pages"),
we can reuse the func in other modules after it was
imported.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@fb.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Acked-by: NKent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

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: NEric Wheeler <bcache@linux.ewheeler.net>
Cc: Kent Overstreet <kent.overstreet@gmail.com>

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]  [<ffffffff816eeac7>] schedule+0x37/0x90
[  720.732963]  [<ffffffffa05192b8>] bch_bucket_alloc+0x188/0x360 [bcache]
[  720.733538]  [<ffffffff810e6950>] ? prepare_to_wait_event+0xf0/0xf0
[  720.734137]  [<ffffffffa05302bd>] bch_prio_write+0x19d/0x340 [bcache]
[  720.734715]  [<ffffffffa05190bf>] bch_allocator_thread+0x3ff/0x470 [bcache]
[  720.735311]  [<ffffffff816ee41c>] ? __schedule+0x2dc/0x950
[  720.735884]  [<ffffffffa0518cc0>] ? invalidate_buckets+0x980/0x980 [bcache]

Registration thread:
[  720.710403] INFO: task bash:3531 blocked for more than 120 seconds.
[  720.715226]  [<ffffffff816eeac7>] schedule+0x37/0x90
[  720.715805]  [<ffffffffa05235cd>] __bch_btree_map_nodes+0x12d/0x150 [bcache]
[  720.716409]  [<ffffffffa0522d30>] ? bch_btree_insert_check_key+0x1c0/0x1c0 [bcache]
[  720.717008]  [<ffffffffa05236e4>] bch_btree_insert+0xf4/0x170 [bcache]
[  720.717586]  [<ffffffff810e6950>] ? prepare_to_wait_event+0xf0/0xf0
[  720.718191]  [<ffffffffa0527d9a>] bch_journal_replay+0x14a/0x290 [bcache]
[  720.718766]  [<ffffffff810cc90d>] ? ttwu_do_activate.constprop.94+0x5d/0x70
[  720.719369]  [<ffffffff810cf684>] ? try_to_wake_up+0x1d4/0x350
[  720.719968]  [<ffffffffa05317d0>] run_cache_set+0x580/0x8e0 [bcache]
[  720.720553]  [<ffffffffa053302e>] register_bcache+0xe2e/0x13b0 [bcache]
[  720.721153]  [<ffffffff81354cef>] kobj_attr_store+0xf/0x20
[  720.721730]  [<ffffffff812a2dad>] sysfs_kf_write+0x3d/0x50
[  720.722327]  [<ffffffff812a225a>] kernfs_fop_write+0x12a/0x180
[  720.722904]  [<ffffffff81225177>] __vfs_write+0x37/0x110
[  720.723503]  [<ffffffff81228048>] ? __sb_start_write+0x58/0x110
[  720.724100]  [<ffffffff812cedb3>] ? security_file_permission+0x23/0xa0
[  720.724675]  [<ffffffff812258a9>] vfs_write+0xa9/0x1b0
[  720.725275]  [<ffffffff8102479c>] ? do_audit_syscall_entry+0x6c/0x70
[  720.725849]  [<ffffffff81226755>] SyS_write+0x55/0xd0
[  720.726451]  [<ffffffff8106a390>] ? do_page_fault+0x30/0x80
[  720.727045]  [<ffffffff816f2cae>] 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: NKent Overstreet <kent.overstreet@gmail.com>
Tested-by: NEric Wheeler <bcache@linux.ewheeler.net>
Cc: stable@vger.kernel.org

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: NEric Wheeler <bcache@linux.ewheeler.net>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: stable@vger.kernel.org

Since commit 63a4cc24, 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: NJens Axboe <axboe@fb.com>

Instead of a flag and an index just make sure an index of 0 means
no need to free the bvec array.  Also move the constants related
to the bvec pools together and use a consistent naming scheme for
them.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

We have assigned sb->block_size before the switch,
so remove the redundant one.
Reviewed-by: NColy Li <colyli@suse.de>
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Acked-by: NEric Wheeler <bcache@lists.ewheeler.net>
Signed-off-by: NJens Axboe <axboe@fb.com>

There is no return in continue_at(), update the documentation.
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Acked-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Cache_sb is not used in cache_alloc, and we have copied
sb info to cache->sb already, remove it.
Reviewed-by: NColy Li <colyli@suse.de>
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

alloc_workqueue replaces deprecated create_workqueue().

Dedicated workqueues have been used since bcache_wq and moving_gc_wq
are workqueues for writes and are being used on a memory reclaim path.
WQ_MEM_RECLAIM has been set to ensure forward progress under memory
pressure.
Since there are only a fixed number of work items, explicit concurrency
limit is unnecessary here.
Signed-off-by: NBhaktipriya Shridhar <bhaktipriya96@gmail.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>

To avoid confusion between REQ_OP_FLUSH, which is handled by
request_fn drivers, and upper layers requesting the block layer
perform a flush sequence along with possibly a WRITE, this patch
renames REQ_FLUSH to REQ_PREFLUSH.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Separate the op from the rq_flag_bits and have bcache
set/get the bio using bio_set_op_attrs/bio_op.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

We currently set REQ_WRITE/WRITE for all non READ IOs
like discard, flush, writesame, etc. In the next patches where we
no longer set up the op as a bitmap, we will not be able to
detect a operation direction like writesame by testing if REQ_WRITE is
set.

This has bcache use the op_is_write helper which will do the right
thing.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

This has callers of submit_bio/submit_bio_wait set the bio->bi_rw
instead of passing it in. This makes that use the same as
generic_make_request and how we set the other bio fields.
Signed-off-by: NMike Christie <mchristi@redhat.com>

Fixed up fs/ext4/crypto.c
Signed-off-by: NJens Axboe <axboe@fb.com>

bch_gc_thread() doesn't mark itself freezable, so calling try_to_freeze()
in its context is just an expensive no-op.
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

bch_allocator_thread() is calling try_to_freeze(), but that's just an
expensive no-op given the fact that the thread is not marked freezable.

Bucket allocator has to be up and running to the very last stages of the
suspend, as the bcache I/O that's in flight (think of writing an
hibernation image to a swap device served by bcache).
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

bch_writeback_thread() is calling try_to_freeze(), but that's just an
expensive no-op given the fact that the thread is not marked freezable.

I/O helper kthreads, exactly such as the bcache writeback thread, actually
shouldn't be freezable, because they are potentially necessary for
finalizing the image write-out.
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NJens Axboe <axboe@fb.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

When bch_cache_set_alloc() fails to kzalloc the cache_set, the
asyncronous closure handling tries to dereference a cache_set that
hadn't yet been allocated inside of cache_set_flush() which is called
by __cache_set_unregister() during cleanup.  This appears to happen only
during an OOM condition on bcache_register.
Signed-off-by: NEric Wheeler <bcache@linux.ewheeler.net>
Cc: stable@vger.kernel.org

Fix null pointer dereference by changing register_cache() to return an int
instead of being void.  This allows it to return -ENOMEM or -ENODEV and
enables upper layers to handle the OOM case without NULL pointer issues.

See this thread:
  http://thread.gmane.org/gmane.linux.kernel.bcache.devel/3521

Fixes this error:
  gargamel:/sys/block/md5/bcache# echo /dev/sdh2 > /sys/fs/bcache/register

  bcache: register_cache() error opening sdh2: cannot allocate memory
  BUG: unable to handle kernel NULL pointer dereference at 00000000000009b8
  IP: [<ffffffffc05a7e8d>] cache_set_flush+0x102/0x15c [bcache]
  PGD 120dff067 PUD 1119a3067 PMD 0
  Oops: 0000 [#1] SMP
  Modules linked in: veth ip6table_filter ip6_tables
  (...)
  CPU: 4 PID: 3371 Comm: kworker/4:3 Not tainted 4.4.2-amd64-i915-volpreempt-20160213bc1 #3
  Hardware name: System manufacturer System Product Name/P8H67-M PRO, BIOS 3904 04/27/2013
  Workqueue: events cache_set_flush [bcache]
  task: ffff88020d5dc280 ti: ffff88020b6f8000 task.ti: ffff88020b6f8000
  RIP: 0010:[<ffffffffc05a7e8d>]  [<ffffffffc05a7e8d>] cache_set_flush+0x102/0x15c [bcache]
Signed-off-by: NEric Wheeler <bcache@linux.ewheeler.net>
Tested-by: NMarc MERLIN <marc@merlins.org>
Cc: <stable@vger.kernel.org>

The bch_writeback_thread might BUG_ON in read_dirty() if
dc->sb==BDEV_STATE_DIRTY and bch_sectors_dirty_init has not yet completed
its related initialization.  This patch downs the dc->writeback_lock until
after initialization is complete, thus preventing bch_writeback_thread
from proceeding prematurely.

See this thread:
  http://thread.gmane.org/gmane.linux.kernel.bcache.devel/3453Signed-off-by: NEric Wheeler <bcache@linux.ewheeler.net>
Tested-by: NMarc MERLIN <marc@merlins.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Previously, it would only scan the entire disk if it was starting from
the very start of the disk - i.e. if the previous scan got to the end.

This was broken by refill_full_stripes(), which updates last_scanned so
that refill_dirty was never triggering the searched_from_start path.

But if we change refill_dirty() to always scan the entire disk if
necessary, regardless of what last_scanned was, the code gets cleaner
and we fix that bug too.
Signed-off-by: NKent Overstreet <kent.overstreet@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@fb.com>

Added a safeguard in the shutdown case. At least while not being
attached it is also possible to trigger a kernel bug by writing into
writeback_running. This change  adds the same check before trying to
wake up the thread for that case.
Signed-off-by: NStefan Bader <stefan.bader@canonical.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@fb.com>

Allows to use register, not register_quiet in udev to avoid "device_busy" error.
The initial patch proposed at https://lkml.org/lkml/2013/8/26/549 by Gabriel de Perthuis
<g2p.code@gmail.com> does not unlock the mutex and hangs the kernel.

See http://thread.gmane.org/gmane.linux.kernel.bcache.devel/2594 for the discussion.

Cc: Denis Bychkov <manover@gmail.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Eric Wheeler <bcache@linux.ewheeler.net>
Cc: Gabriel de Perthuis <g2p.code@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@fb.com>

In bcache_init() function it forgot to unregister reboot notifier if
bcache fails to unregister a block device.  This commit fixes this.
Signed-off-by: NZheng Liu <wenqing.lz@taobao.com>
Tested-by: NJoshua Schmid <jschmid@suse.com>
Tested-by: NEric Wheeler <bcache@linux.ewheeler.net>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Tested-by: NJoshua Schmid <jschmid@suse.com>
Tested-by: NEric Wheeler <bcache@linux.ewheeler.net>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@fb.com>

This bug can be reproduced by the following script:

  #!/bin/bash

  bcache_sysfs="/sys/fs/bcache"

  function clear_cache()
  {
  	if [ ! -e $bcache_sysfs ]; then
  		echo "no bcache sysfs"
  		exit
  	fi

  	cset_uuid=$(ls -l $bcache_sysfs|head -n 2|tail -n 1|awk '{print $9}')
  	sudo sh -c "echo $cset_uuid > /sys/block/sdb/sdb1/bcache/detach"
  	sleep 5
  	sudo sh -c "echo $cset_uuid > /sys/block/sdb/sdb1/bcache/attach"
  }

  for ((i=0;i<10;i++)); do
  	clear_cache
  done

The warning messages look like below:
[  275.948611] ------------[ cut here ]------------
[  275.963840] WARNING: at fs/sysfs/dir.c:512 sysfs_add_one+0xb8/0xd0() (Tainted: P        W
---------------   )
[  275.979253] Hardware name: Tecal RH2285
[  275.994106] sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:09.0/0000:08:00.0/host4/target4:2:1/4:2:1:0/block/sdb/sdb1/bcache/cache'
[  276.024105] Modules linked in: bcache tcp_diag inet_diag ipmi_devintf ipmi_si ipmi_msghandler
bonding 8021q garp stp llc ipv6 ext3 jbd loop sg iomemory_vsl(P) bnx2 microcode serio_raw i2c_i801
i2c_core iTCO_wdt iTCO_vendor_support i7core_edac edac_core shpchp ext4 jbd2 mbcache megaraid_sas
pata_acpi ata_generic ata_piix dm_mod [last unloaded: scsi_wait_scan]
[  276.072643] Pid: 2765, comm: sh Tainted: P        W  ---------------    2.6.32 #1
[  276.089315] Call Trace:
[  276.105801]  [<ffffffff81070fe7>] ? warn_slowpath_common+0x87/0xc0
[  276.122650]  [<ffffffff810710d6>] ? warn_slowpath_fmt+0x46/0x50
[  276.139361]  [<ffffffff81205c08>] ? sysfs_add_one+0xb8/0xd0
[  276.156012]  [<ffffffff8120609b>] ? sysfs_do_create_link+0x12b/0x170
[  276.172682]  [<ffffffff81206113>] ? sysfs_create_link+0x13/0x20
[  276.189282]  [<ffffffffa03bda21>] ? bcache_device_link+0xc1/0x110 [bcache]
[  276.205993]  [<ffffffffa03bfa08>] ? bch_cached_dev_attach+0x478/0x4f0 [bcache]
[  276.222794]  [<ffffffffa03c4a17>] ? bch_cached_dev_store+0x627/0x780 [bcache]
[  276.239680]  [<ffffffff8116783a>] ? alloc_pages_current+0xaa/0x110
[  276.256594]  [<ffffffff81203b15>] ? sysfs_write_file+0xe5/0x170
[  276.273364]  [<ffffffff811887b8>] ? vfs_write+0xb8/0x1a0
[  276.290133]  [<ffffffff811890b1>] ? sys_write+0x51/0x90
[  276.306368]  [<ffffffff8100c072>] ? system_call_fastpath+0x16/0x1b
[  276.322301] ---[ end trace 9f5d4fcdd0c3edfb ]---
[  276.338241] ------------[ cut here ]------------
[  276.354109] WARNING: at /home/wenqing.lz/bcache/bcache/super.c:720
bcache_device_link+0xdf/0x110 [bcache]() (Tainted: P        W  ---------------   )
[  276.386017] Hardware name: Tecal RH2285
[  276.401430] Couldn't create device <-> cache set symlinks
[  276.401759] Modules linked in: bcache tcp_diag inet_diag ipmi_devintf ipmi_si ipmi_msghandler
bonding 8021q garp stp llc ipv6 ext3 jbd loop sg iomemory_vsl(P) bnx2 microcode serio_raw i2c_i801
i2c_core iTCO_wdt iTCO_vendor_support i7core_edac edac_core shpchp ext4 jbd2 mbcache megaraid_sas
pata_acpi ata_generic ata_piix dm_mod [last unloaded: scsi_wait_scan]
[  276.465477] Pid: 2765, comm: sh Tainted: P        W  ---------------    2.6.32 #1
[  276.482169] Call Trace:
[  276.498610]  [<ffffffff81070fe7>] ? warn_slowpath_common+0x87/0xc0
[  276.515405]  [<ffffffff810710d6>] ? warn_slowpath_fmt+0x46/0x50
[  276.532059]  [<ffffffffa03bda3f>] ? bcache_device_link+0xdf/0x110 [bcache]
[  276.548808]  [<ffffffffa03bfa08>] ? bch_cached_dev_attach+0x478/0x4f0 [bcache]
[  276.565569]  [<ffffffffa03c4a17>] ? bch_cached_dev_store+0x627/0x780 [bcache]
[  276.582418]  [<ffffffff8116783a>] ? alloc_pages_current+0xaa/0x110
[  276.599341]  [<ffffffff81203b15>] ? sysfs_write_file+0xe5/0x170
[  276.616142]  [<ffffffff811887b8>] ? vfs_write+0xb8/0x1a0
[  276.632607]  [<ffffffff811890b1>] ? sys_write+0x51/0x90
[  276.648671]  [<ffffffff8100c072>] ? system_call_fastpath+0x16/0x1b
[  276.664756] ---[ end trace 9f5d4fcdd0c3edfc ]---

We forget to clear BCACHE_DEV_UNLINK_DONE flag in bcache_device_attach()
function when we attach a backing device first time.  After detaching this
backing device, this flag will be true and sysfs_remove_link() isn't called in
bcache_device_unlink().  Then when we attach this backing device again,
sysfs_create_link() will return EEXIST error in bcache_device_link().

So the fix is trival and we clear this flag in bcache_device_link().
Signed-off-by: NZheng Liu <wenqing.lz@taobao.com>
Tested-by: NJoshua Schmid <jschmid@suse.com>
Tested-by: NEric Wheeler <bcache@linux.ewheeler.net>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Tested-by: NEric Wheeler <bcache@linux.ewheeler.net>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@fb.com>

Subject :	[PATCH v2] bcache: fix a livelock in btree lock
Date :	Wed, 25 Feb 2015 20:32:09 +0800 (02/25/2015 04:32:09 AM)

This commit tries to fix a livelock in bcache.  This livelock might
happen when we causes a huge number of cache misses simultaneously.

When we get a cache miss, bcache will execute the following path.

->cached_dev_make_request()
  ->cached_dev_read()
    ->cached_lookup()
      ->bch->btree_map_keys()
        ->btree_root()  <------------------------
          ->bch_btree_map_keys_recurse()        |
            ->cache_lookup_fn()                 |
              ->cached_dev_cache_miss()         |
                ->bch_btree_insert_check_key() -|
                  [If btree->seq is not equal to seq + 1, we should return
                   EINTR and traverse btree again.]

In bch_btree_insert_check_key() function we first need to check upgrade
flag (op->lock == -1), and when this flag is true we need to release
read btree->lock and try to take write btree->lock.  During taking and
releasing this write lock, btree->seq will be monotone increased in
order to prevent other threads modify this in cache miss (see btree.h:74).
But if there are some cache misses caused by some requested, we could
meet a livelock because btree->seq is always changed by others.  Thus no
one can make progress.

This commit will try to take write btree->lock if it encounters a race
when we traverse btree.  Although it sacrifice the scalability but we
can ensure that only one can modify the btree.
Signed-off-by: NZheng Liu <wenqing.lz@taobao.com>
Tested-by: NJoshua Schmid <jschmid@suse.com>
Tested-by: NEric Wheeler <bcache@linux.ewheeler.net>
Cc: Joshua Schmid <jschmid@suse.com>
Cc: Zhu Yanhai <zhu.yanhai@gmail.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@fb.com>

No functional changes in this patch, but it prepares us for returning
a more useful cookie related to the IO that was queued up.
Signed-off-by: NJens Axboe <axboe@fb.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NKeith Busch <keith.busch@intel.com>

WORK_STRUCT_PENDING is a mask for testing the pending bit.
test_bit() expects the number of the bit and we need to
use WORK_STRUCT_PENDING_BIT there.

Also work_data_bits() is defined in workqueues.h now.

I have noticed this just by chance when looking how
WORK_STRUCT_PENDING_BIT is used. The change is compile
tested.
Signed-off-by: NPetr Mladek <pmladek@suse.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

The bcache driver has always accepted arbitrarily large bios and split
them internally.  Now that every driver must accept arbitrarily large
bios this code isn't nessecary anymore.

Cc: linux-bcache@vger.kernel.org
Signed-off-by: NKent Overstreet <kent.overstreet@gmail.com>
[dpark: add more description in commit message]
Signed-off-by: NDongsu Park <dpark@posteo.net>
Signed-off-by: NMing Lin <ming.l@ssi.samsung.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Currently we have two different ways to signal an I/O error on a BIO:

 (1) by clearing the BIO_UPTODATE flag
 (2) by returning a Linux errno value to the bi_end_io callback

The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario.  Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.

So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Some drivers use it now, others just set the limits field manually.
But in preparation for splitting this into a hard and soft limit,
ensure that they all call the proper function for setting the hw
limit for discards.
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

This is horribly confusing, it breaks the flow of the code without
it being apparent in the caller.
Signed-off-by: NJens Axboe <axboe@fb.com>
Acked-by: NChristoph Hellwig <hch@lst.de>