linux-toradex.git/drivers/md/bcache/btree.c, branch v4.4.126

bcache: check return value of register_shrinker

2018-02-03T16:04:27+00:00

[ Upstream commit 6c4ca1e36cdc1a0a7a84797804b87920ccbebf51 ]

register_shrinker is now __must_check, so check it to kill a warning.
Caller of bch_btree_cache_alloc in super.c appropriately checks return
value so this is fully plumbed through.

This V2 fixes checkpatch warnings and improves the commit description,
as I was too hasty getting the previous version out.

Signed-off-by: Michael Lyle 
Reviewed-by: Vojtech Pavlik 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

bcache: Make gc wakeup sane, remove set_task_state()

2017-02-23T16:43:10+00:00

commit be628be09563f8f6e81929efbd7cf3f45c344416 upstream.

Signed-off-by: Kent Overstreet 
Signed-off-by: Greg Kroah-Hartman

bcache: Add a cond_resched() call to gc

2016-03-03T23:07:09+00:00

commit c5f1e5adf956e3ba82d204c7c141a75da9fa449a upstream.

Signed-off-by: Takashi Iwai 
Tested-by: Eric Wheeler 
Cc: Kent Overstreet 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: fix a livelock when we cause a huge number of cache misses

2016-03-03T23:07:09+00:00

commit 2ef9ccbfcb90cf84bdba320a571b18b05c41101b upstream.

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: Zheng Liu 
Tested-by: Joshua Schmid 
Tested-by: Eric Wheeler 
Cc: Joshua Schmid 
Cc: Zhu Yanhai 
Cc: Kent Overstreet 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: add a bi_error field to struct bio

2015-07-29T14:55:15+00:00

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: Christoph Hellwig 
Reviewed-by: Hannes Reinecke 
Reviewed-by: NeilBrown 
Signed-off-by: Jens Axboe

bcache: try to set b->parent properly

2014-08-04T22:23:04+00:00

bcache_flash_dev.ktest would reliably crash with 8k and 16k bucket size
before; now it passes.

Change-Id: Ib542232235e39298c3a7548fe52b645cabb823d1

bcache: fix use-after-free in btree_gc_coalesce()

2014-08-04T22:23:04+00:00

If we goto out_nocoalesce after we free new_nodes[0], we end up freeing
new_nodes[0] again. This was generating a lockdep warning. The fix is
to set new_nodes[0] to NULL, since the out_nocoalesce path safely
ignores NULL entries in the new_nodes array.

This regression was introduced in 2d7f9531.

Change-Id: I76564d7257800583214376b4bacf236cda90c89c

bcache: fix crash in bcache_btree_node_alloc_fail tracepoint

2014-08-04T22:23:03+00:00

'b' was NULL.

Change-Id: Icac0fd04afa2d23f213d96d51afd53374e6dd0c0

bcache: Allocate bounce buffers with GFP_NOWAIT

2014-08-04T22:23:03+00:00

There's no point in blocking on these allocations, since our fallback paths will
probably go faster than blocking.

Change-Id: I733ca202c25cb36bde02607a0a60552229a4241c

bcache: Make sure to pass GFP_WAIT to mempool_alloc()

2014-08-04T22:23:03+00:00

this was very wrong - mempool_alloc() only guarantees success with GFP_WAIT.
bcache uses GFP_NOWAIT in various other places where we have a fallback,
circuits must've gotten crossed when writing this code or something.

Signed-off-by: Kent Overstreet