bcache: Initialize sectors_dirty when attaching

Previously, dirty_data wouldn't get initialized until the first garbage
collection... which was a bit of a problem for background writeback (as
the PD controller keys off of it) and also confusing for users.

This is also prep work for making background writeback aware of raid5/6
stripes.

Signed-off-by: Kent Overstreet <koverstreet@google.com>

4 files changed, 39 insertions, 29 deletions

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 6fa5a1e33c49..d099d8894c2f 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -438,7 +438,6 @@ struct bcache_device {
         atomic_t                detaching;
 
         atomic_long_t           sectors_dirty;
-        unsigned long           sectors_dirty_gc;
         unsigned long           sectors_dirty_last;
         long                    sectors_dirty_derivative;
 
@@ -1225,6 +1224,7 @@ void bch_cache_set_stop(struct cache_set *);
 struct cache_set *bch_cache_set_alloc(struct cache_sb *);
 void bch_btree_cache_free(struct cache_set *);
 int bch_btree_cache_alloc(struct cache_set *);
+void bch_sectors_dirty_init(struct cached_dev *);
 void bch_cached_dev_writeback_init(struct cached_dev *);
 void bch_moving_init_cache_set(struct cache_set *);
 
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 53a0f4ef4e32..230c3a6d9be2 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1119,11 +1119,8 @@ static int btree_gc_mark_node(struct btree *b, unsigned *keys,
                 gc->nkeys++;
 
                 gc->data += KEY_SIZE(k);
-                if (KEY_DIRTY(k)) {
+                if (KEY_DIRTY(k))
                         gc->dirty += KEY_SIZE(k);
-                        if (d)
-                                d->sectors_dirty_gc += KEY_SIZE(k);
-                }
         }
 
         for (t = b->sets; t <= &b->sets[b->nsets]; t++)
@@ -1377,7 +1374,6 @@ static void btree_gc_start(struct cache_set *c)
 {
         struct cache *ca;
         struct bucket *b;
-        struct bcache_device **d;
         unsigned i;
 
         if (!c->gc_mark_valid)
@@ -1395,12 +1391,6 @@ static void btree_gc_start(struct cache_set *c)
                                 SET_GC_MARK(b, GC_MARK_RECLAIMABLE);
                 }
 
-        for (d = c->devices;
-             d < c->devices + c->nr_uuids;
-             d++)
-                if (*d)
-                        (*d)->sectors_dirty_gc = 0;
-
         mutex_unlock(&c->bucket_lock);
 }
 
@@ -1409,7 +1399,6 @@ size_t bch_btree_gc_finish(struct cache_set *c)
         size_t available = 0;
         struct bucket *b;
         struct cache *ca;
-        struct bcache_device **d;
         unsigned i;
 
         mutex_lock(&c->bucket_lock);
@@ -1452,22 +1441,6 @@ size_t bch_btree_gc_finish(struct cache_set *c)
                 }
         }
 
-        for (d = c->devices;
-             d < c->devices + c->nr_uuids;
-             d++)
-                if (*d) {
-                        unsigned long last =
-                                atomic_long_read(&((*d)->sectors_dirty));
-                        long difference = (*d)->sectors_dirty_gc - last;
-
-                        pr_debug("sectors dirty off by %li", difference);
-
-                        (*d)->sectors_dirty_last += difference;
-
-                        atomic_long_set(&((*d)->sectors_dirty),
-                                        (*d)->sectors_dirty_gc);
-                }
-
         mutex_unlock(&c->bucket_lock);
         return available;
 }
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 3c8474161e8e..dbfa1c38e85e 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -961,6 +961,7 @@ int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c)
         atomic_set(&dc->count, 1);
 
         if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
+                bch_sectors_dirty_init(dc);
                 atomic_set(&dc->has_dirty, 1);
                 atomic_inc(&dc->count);
                 bch_writeback_queue(dc);
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 82f6d4577be2..553949eefd51 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -377,6 +377,42 @@ err:
         refill_dirty(cl);
 }
 
+/* Init */
+
+static int bch_btree_sectors_dirty_init(struct btree *b, struct btree_op *op,
+                                        struct cached_dev *dc)
+{
+        struct bkey *k;
+        struct btree_iter iter;
+
+        bch_btree_iter_init(b, &iter, &KEY(dc->disk.id, 0, 0));
+        while ((k = bch_btree_iter_next_filter(&iter, b, bch_ptr_bad)))
+                if (!b->level) {
+                        if (KEY_INODE(k) > dc->disk.id)
+                                break;
+
+                        if (KEY_DIRTY(k))
+                                atomic_long_add(KEY_SIZE(k),
+                                                &dc->disk.sectors_dirty);
+                } else {
+                        btree(sectors_dirty_init, k, b, op, dc);
+                        if (KEY_INODE(k) > dc->disk.id)
+                                break;
+
+                        cond_resched();
+                }
+
+        return 0;
+}
+
+void bch_sectors_dirty_init(struct cached_dev *dc)
+{
+        struct btree_op op;
+
+        bch_btree_op_init_stack(&op);
+        btree_root(sectors_dirty_init, dc->disk.c, &op, dc);
+}
+
 void bch_cached_dev_writeback_init(struct cached_dev *dc)
 {
         closure_init_unlocked(&dc->writeback);