Patch "bcache: initialize dirty stripes in flash_dev_run()" has been added to the 3.18-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    bcache: initialize dirty stripes in flash_dev_run()

to the 3.18-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     bcache-initialize-dirty-stripes-in-flash_dev_run.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 175206cf9ab63161dec74d9cd7f9992e062491f5 Mon Sep 17 00:00:00 2001
From: Tang Junhui <tang.junhui@zte.com.cn>
Date: Thu, 7 Sep 2017 01:28:53 +0800
Subject: bcache: initialize dirty stripes in flash_dev_run()

From: Tang Junhui <tang.junhui@zte.com.cn>

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 <tang.junhui@zte.com.cn>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/md/bcache/super.c     |    3 ++-
 drivers/md/bcache/writeback.c |    8 ++++----
 drivers/md/bcache/writeback.h |    2 +-
 3 files changed, 7 insertions(+), 6 deletions(-)

--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1054,7 +1054,7 @@ int bch_cached_dev_attach(struct cached_
 	}
 
 	if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
-		bch_sectors_dirty_init(dc);
+		bch_sectors_dirty_init(&dc->disk);
 		atomic_set(&dc->has_dirty, 1);
 		atomic_inc(&dc->count);
 		bch_writeback_queue(dc);
@@ -1258,6 +1258,7 @@ static int flash_dev_run(struct cache_se
 		goto err;
 
 	bcache_device_attach(d, c, u - c->uuids);
+	bch_sectors_dirty_init(d);
 	bch_flash_dev_request_init(d);
 	add_disk(d->disk);
 
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -488,17 +488,17 @@ static int sectors_dirty_init_fn(struct
 	return MAP_CONTINUE;
 }
 
-void bch_sectors_dirty_init(struct cached_dev *dc)
+void bch_sectors_dirty_init(struct bcache_device *d)
 {
 	struct sectors_dirty_init op;
 
 	bch_btree_op_init(&op.op, -1);
-	op.inode = dc->disk.id;
+	op.inode = d->id;
 
-	bch_btree_map_keys(&op.op, dc->disk.c, &KEY(op.inode, 0, 0),
+	bch_btree_map_keys(&op.op, d->c, &KEY(op.inode, 0, 0),
 			   sectors_dirty_init_fn, 0);
 
-	dc->disk.sectors_dirty_last = bcache_dev_sectors_dirty(&dc->disk);
+	d->sectors_dirty_last = bcache_dev_sectors_dirty(d);
 }
 
 void bch_cached_dev_writeback_init(struct cached_dev *dc)
--- a/drivers/md/bcache/writeback.h
+++ b/drivers/md/bcache/writeback.h
@@ -85,7 +85,7 @@ static inline void bch_writeback_add(str
 
 void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
 
-void bch_sectors_dirty_init(struct cached_dev *dc);
+void bch_sectors_dirty_init(struct bcache_device *);
 void bch_cached_dev_writeback_init(struct cached_dev *);
 int bch_cached_dev_writeback_start(struct cached_dev *);
 


Patches currently in stable-queue which might be from tang.junhui@zte.com.cn are

queue-3.18/bcache-correct-cache_dirty_target-in-__update_writeback_rate.patch
queue-3.18/bcache-fix-for-gc-and-write-back-race.patch
queue-3.18/bcache-initialize-dirty-stripes-in-flash_dev_run.patch