linux-stable.git/drivers/md/bcache, branch v3.13

bcache: New writeback PD controller

2013-12-16T22:22:59+00:00

The old writeback PD controller could get into states where it had throttled all
the way down and take way too long to recover - it was too complicated to really
understand what it was doing.

This rewrites a good chunk of it to hopefully be simpler and make more sense,
and it also pays more attention to units which should make the behaviour a bit
easier to understand.

Signed-off-by: Kent Overstreet

bcache: bugfix for race between moving_gc and bucket_invalidate

2013-12-16T22:22:58+00:00

There is a possibility for a bucket to be invalidated by the allocator
while moving_gc was copying it's contents to another bucket, if the
bucket only held cached data. To prevent this moving checks for
a stale ptr (to an invalidated bucket), before and after reads.
It it finds one, it simply ignores moving that data. This only
affects bcache if the moving_gc was turned on, note that it's
off by default.

Signed-off-by: Nicholas Swenson 
Signed-off-by: Kent Overstreet

bcache: fix for gc and writeback race

2013-12-16T22:22:58+00:00

Garbage collector needs to check keys in the writeback keybuf to
make sure it's not invalidating buckets to which the writeback
keys point to.

Signed-off-by: Nicholas Swenson 
Signed-off-by: Kent Overstreet

bcache: bugfix - moving_gc now moves only correct buckets

2013-12-16T22:22:58+00:00

Removed gc_move_threshold because picking buckets only by
threshold could lead moving extra buckets (ei. if there are
buckets at the threshold that aren't supposed to be moved
do to space considerations).

This is replaced by a GC_MOVE bit in the gc_mark bitmask.
Now only marked buckets get moved.

Signed-off-by: Nicholas Swenson 
Signed-off-by: Kent Overstreet

bcache: fix for gc crashing when no sectors are used

2013-12-16T22:22:57+00:00

Signed-off-by: Nicholas Swenson 
Signed-off-by: Kent Overstreet

bcache: Fix heap_peek() macro

2013-12-16T22:22:57+00:00

Signed-off-by: Nicholas Swenson 
Signed-off-by: Kent Overstreet

bcache: Fix for can_attach_cache()

2013-12-16T22:22:57+00:00

Signed-off-by: Nicholas Swenson 
Signed-off-by: Kent Overstreet

bcache: Fix dirty_data accounting

2013-12-16T22:22:16+00:00

Dirty data accounting wasn't quite right - firstly, we were adding the key we're
inserting after it could have merged with another dirty key already in the
btree, and secondly we could sometimes pass the wrong offset to
bcache_dev_sectors_dirty_add() for dirty data we were overwriting - which is
important when tracking dirty data by stripe.

NOTE FOR BACKPORTERS: For 3.10 (and 3.11?) there's other accounting fixes
necessary that got squashed in with other patches; the full patch against 3.10
is 408cc2f47eeac93a, available at:
  git://evilpiepirate.org/~kent/linux-bcache.git bcache-3.10-writeback-fixes

Signed-off-by: Kent Overstreet 
Cc: linux-stable  # >= v3.10

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 2a46036..4a12b2f 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1817,7 +1817,8 @@ static bool fix_overlapping_extents(struct btree *b, struct bkey *insert,
 			if (KEY_START(k) > KEY_START(insert) + sectors_found)
 				goto check_failed;

-			if (KEY_PTRS(replace_key) != KEY_PTRS(k))
+			if (KEY_PTRS(k) != KEY_PTRS(replace_key) ||
+			    KEY_DIRTY(k) != KEY_DIRTY(replace_key))
 				goto check_failed;

 			/* skip past gen */

bcache: Use uninterruptible sleep in writeback

2013-12-16T22:04:57+00:00

We're just waiting on kthread_should_stop(), nothing else, so
interruptible sleep was wrong here.

Signed-off-by: Kent Overstreet

bcache: kthread don't set writeback task to INTERUPTIBLE

2013-12-16T22:04:57+00:00

at the beginning (schedule_timout_interuptible) and others
do his on their own

This prevents wrong load average calculation (load of 1 per thread)

Signed-off-by: Kent Overstreet