9 files changed, 110 insertions, 67 deletions

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index b39f6f0b45f2..0f12382aa35d 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -498,7 +498,7 @@ struct cached_dev {
          */
         atomic_t                has_dirty;
 
-        struct ratelimit        writeback_rate;
+        struct bch_ratelimit    writeback_rate;
         struct delayed_work     writeback_rate_update;
 
         /*
@@ -507,10 +507,9 @@ struct cached_dev {
          */
         sector_t                last_read;
 
-        /* Number of writeback bios in flight */
-        atomic_t                in_flight;
+        /* Limit number of writeback bios in flight */
+        struct semaphore        in_flight;
         struct closure_with_timer writeback;
-        struct closure_waitlist writeback_wait;
 
         struct keybuf           writeback_keys;
 
diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c
index 8010eed06a51..22d1ae72c282 100644
--- a/drivers/md/bcache/bset.c
+++ b/drivers/md/bcache/bset.c
@@ -926,28 +926,45 @@ struct bkey *bch_next_recurse_key(struct btree *b, struct bkey *search)
 
 /* Mergesort */
 
+static void sort_key_next(struct btree_iter *iter,
+                          struct btree_iter_set *i)
+{
+        i->k = bkey_next(i->k);
+
+        if (i->k == i->end)
+                *i = iter->data[--iter->used];
+}
+
 static void btree_sort_fixup(struct btree_iter *iter)
 {
         while (iter->used > 1) {
                 struct btree_iter_set *top = iter->data, *i = top + 1;
-                struct bkey *k;
 
                 if (iter->used > 2 &&
                     btree_iter_cmp(i[0], i[1]))
                         i++;
 
-                for (k = i->k;
-                     k != i->end && bkey_cmp(top->k, &START_KEY(k)) > 0;
-                     k = bkey_next(k))
-                        if (top->k > i->k)
-                                __bch_cut_front(top->k, k);
-                        else if (KEY_SIZE(k))
-                                bch_cut_back(&START_KEY(k), top->k);
-
-                if (top->k < i->k || k == i->k)
+                if (bkey_cmp(top->k, &START_KEY(i->k)) <= 0)
                         break;
 
-                heap_sift(iter, i - top, btree_iter_cmp);
+                if (!KEY_SIZE(i->k)) {
+                        sort_key_next(iter, i);
+                        heap_sift(iter, i - top, btree_iter_cmp);
+                        continue;
+                }
+
+                if (top->k > i->k) {
+                        if (bkey_cmp(top->k, i->k) >= 0)
+                                sort_key_next(iter, i);
+                        else
+                                bch_cut_front(top->k, i->k);
+
+                        heap_sift(iter, i - top, btree_iter_cmp);
+                } else {
+                        /* can't happen because of comparison func */
+                        BUG_ON(!bkey_cmp(&START_KEY(top->k), &START_KEY(i->k)));
+                        bch_cut_back(&START_KEY(i->k), top->k);
+                }
         }
 }
 
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index f9764e61978b..f42fc7ed9cd6 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -255,7 +255,7 @@ void bch_btree_node_read(struct btree *b)
 
         return;
 err:
-        bch_cache_set_error(b->c, "io error reading bucket %lu",
+        bch_cache_set_error(b->c, "io error reading bucket %zu",
                             PTR_BUCKET_NR(b->c, &b->key, 0));
 }
 
@@ -612,7 +612,7 @@ static unsigned long bch_mca_scan(struct shrinker *shrink,
                 return SHRINK_STOP;
 
         /* Return -1 if we can't do anything right now */
-        if (sc->gfp_mask & __GFP_WAIT)
+        if (sc->gfp_mask & __GFP_IO)
                 mutex_lock(&c->bucket_lock);
         else if (!mutex_trylock(&c->bucket_lock))
                 return -1;
diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
index ba95ab84b2be..8435f81e5d85 100644
--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -153,7 +153,8 @@ int bch_journal_read(struct cache_set *c, struct list_head *list,
                 bitmap_zero(bitmap, SB_JOURNAL_BUCKETS);
                 pr_debug("%u journal buckets", ca->sb.njournal_buckets);
 
-                /* Read journal buckets ordered by golden ratio hash to quickly
+                /*
+                 * Read journal buckets ordered by golden ratio hash to quickly
                  * find a sequence of buckets with valid journal entries
                  */
                 for (i = 0; i < ca->sb.njournal_buckets; i++) {
@@ -166,18 +167,20 @@ int bch_journal_read(struct cache_set *c, struct list_head *list,
                                 goto bsearch;
                 }
 
-                /* If that fails, check all the buckets we haven't checked
+                /*
+                 * If that fails, check all the buckets we haven't checked
                  * already
                  */
                 pr_debug("falling back to linear search");
 
-                for (l = 0; l < ca->sb.njournal_buckets; l++) {
-                        if (test_bit(l, bitmap))
-                                continue;
-
+                for (l = find_first_zero_bit(bitmap, ca->sb.njournal_buckets);
+                     l < ca->sb.njournal_buckets;
+                     l = find_next_zero_bit(bitmap, ca->sb.njournal_buckets, l + 1))
                         if (read_bucket(l))
                                 goto bsearch;
-                }
+
+                if (list_empty(list))
+                        continue;
 bsearch:
                 /* Binary search */
                 m = r = find_next_bit(bitmap, ca->sb.njournal_buckets, l + 1);
@@ -197,10 +200,12 @@ bsearch:
                                 r = m;
                 }
 
-                /* Read buckets in reverse order until we stop finding more
+                /*
+                 * Read buckets in reverse order until we stop finding more
                  * journal entries
                  */
-                pr_debug("finishing up");
+                pr_debug("finishing up: m %u njournal_buckets %u",
+                         m, ca->sb.njournal_buckets);
                 l = m;
 
                 while (1) {
@@ -228,9 +233,10 @@ bsearch:
                         }
         }
 
-        c->journal.seq = list_entry(list->prev,
-                                    struct journal_replay,
-                                    list)->j.seq;
+        if (!list_empty(list))
+                c->journal.seq = list_entry(list->prev,
+                                            struct journal_replay,
+                                            list)->j.seq;
 
         return 0;
 #undef read_bucket
@@ -428,7 +434,7 @@ static void do_journal_discard(struct cache *ca)
                 return;
         }
 
-        switch (atomic_read(&ja->discard_in_flight) == DISCARD_IN_FLIGHT) {
+        switch (atomic_read(&ja->discard_in_flight)) {
         case DISCARD_IN_FLIGHT:
                 return;
 
@@ -689,6 +695,7 @@ void bch_journal_meta(struct cache_set *c, struct closure *cl)
                 if (cl)
                         BUG_ON(!closure_wait(&w->wait, cl));
 
+                closure_flush(&c->journal.io);
                 __journal_try_write(c, true);
         }
 }
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 786a1a4f74d8..b6a74bcbb08f 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -996,17 +996,19 @@ static void request_write(struct cached_dev *dc, struct search *s)
                 closure_bio_submit(bio, cl, s->d);
         } else {
                 bch_writeback_add(dc);
+                s->op.cache_bio = bio;
 
-                if (s->op.flush_journal) {
+                if (bio->bi_rw & REQ_FLUSH) {
                         /* Also need to send a flush to the backing device */
-                        s->op.cache_bio = bio_clone_bioset(bio, GFP_NOIO,
-                                                           dc->disk.bio_split);
-
-                        bio->bi_size = 0;
-                        bio->bi_vcnt = 0;
-                        closure_bio_submit(bio, cl, s->d);
-                } else {
-                        s->op.cache_bio = bio;
+                        struct bio *flush = bio_alloc_bioset(0, GFP_NOIO,
+                                                             dc->disk.bio_split);
+
+                        flush->bi_rw    = WRITE_FLUSH;
+                        flush->bi_bdev  = bio->bi_bdev;
+                        flush->bi_end_io = request_endio;
+                        flush->bi_private = cl;
+
+                        closure_bio_submit(flush, cl, s->d);
                 }
         }
 out:
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 4fe6ab2fbe2e..924dcfdae111 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -223,8 +223,13 @@ STORE(__cached_dev)
         }
 
         if (attr == &sysfs_label) {
-                /* note: endlines are preserved */
-                memcpy(dc->sb.label, buf, SB_LABEL_SIZE);
+                if (size > SB_LABEL_SIZE)
+                        return -EINVAL;
+                memcpy(dc->sb.label, buf, size);
+                if (size < SB_LABEL_SIZE)
+                        dc->sb.label[size] = '\0';
+                if (size && dc->sb.label[size - 1] == '\n')
+                        dc->sb.label[size - 1] = '\0';
                 bch_write_bdev_super(dc, NULL);
                 if (dc->disk.c) {
                         memcpy(dc->disk.c->uuids[dc->disk.id].label,
diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
index 98eb81159a22..420dad545c7d 100644
--- a/drivers/md/bcache/util.c
+++ b/drivers/md/bcache/util.c
@@ -190,7 +190,16 @@ void bch_time_stats_update(struct time_stats *stats, uint64_t start_time)
         stats->last = now ?: 1;
 }
 
-unsigned bch_next_delay(struct ratelimit *d, uint64_t done)
+/**
+ * bch_next_delay() - increment @d by the amount of work done, and return how
+ * long to delay until the next time to do some work.
+ *
+ * @d - the struct bch_ratelimit to update
+ * @done - the amount of work done, in arbitrary units
+ *
+ * Returns the amount of time to delay by, in jiffies
+ */
+uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done)
 {
         uint64_t now = local_clock();
 
diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h
index 1ae2a73ad85f..ea345c6896f4 100644
--- a/drivers/md/bcache/util.h
+++ b/drivers/md/bcache/util.h
@@ -450,17 +450,23 @@ read_attribute(name ## _last_ ## frequency_units)
         (ewma) >> factor;                                               \
 })
 
-struct ratelimit {
+struct bch_ratelimit {
+        /* Next time we want to do some work, in nanoseconds */
         uint64_t                next;
+
+        /*
+         * Rate at which we want to do work, in units per nanosecond
+         * The units here correspond to the units passed to bch_next_delay()
+         */
         unsigned                rate;
 };
 
-static inline void ratelimit_reset(struct ratelimit *d)
+static inline void bch_ratelimit_reset(struct bch_ratelimit *d)
 {
         d->next = local_clock();
 }
 
-unsigned bch_next_delay(struct ratelimit *d, uint64_t done);
+uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done);
 
 #define __DIV_SAFE(n, d, zero)                                          \
 ({                                                                      \
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 22cbff551628..ba3ee48320f2 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -94,11 +94,15 @@ static void update_writeback_rate(struct work_struct *work)
 
 static unsigned writeback_delay(struct cached_dev *dc, unsigned sectors)
 {
+        uint64_t ret;
+
         if (atomic_read(&dc->disk.detaching) ||
             !dc->writeback_percent)
                 return 0;
 
-        return bch_next_delay(&dc->writeback_rate, sectors * 10000000ULL);
+        ret = bch_next_delay(&dc->writeback_rate, sectors * 10000000ULL);
+
+        return min_t(uint64_t, ret, HZ);
 }
 
 /* Background writeback */
@@ -208,7 +212,7 @@ normal_refill:
 
         up_write(&dc->writeback_lock);
 
-        ratelimit_reset(&dc->writeback_rate);
+        bch_ratelimit_reset(&dc->writeback_rate);
 
         /* Punt to workqueue only so we don't recurse and blow the stack */
         continue_at(cl, read_dirty, dirty_wq);
@@ -318,9 +322,7 @@ static void write_dirty_finish(struct closure *cl)
         }
 
         bch_keybuf_del(&dc->writeback_keys, w);
-        atomic_dec_bug(&dc->in_flight);
-
-        closure_wake_up(&dc->writeback_wait);
+        up(&dc->in_flight);
 
         closure_return_with_destructor(cl, dirty_io_destructor);
 }
@@ -349,7 +351,7 @@ static void write_dirty(struct closure *cl)
 
         closure_bio_submit(&io->bio, cl, &io->dc->disk);
 
-        continue_at(cl, write_dirty_finish, dirty_wq);
+        continue_at(cl, write_dirty_finish, system_wq);
 }
 
 static void read_dirty_endio(struct bio *bio, int error)
@@ -369,7 +371,7 @@ static void read_dirty_submit(struct closure *cl)
 
         closure_bio_submit(&io->bio, cl, &io->dc->disk);
 
-        continue_at(cl, write_dirty, dirty_wq);
+        continue_at(cl, write_dirty, system_wq);
 }
 
 static void read_dirty(struct closure *cl)
@@ -394,12 +396,8 @@ static void read_dirty(struct closure *cl)
 
                 if (delay > 0 &&
                     (KEY_START(&w->key) != dc->last_read ||
-                     jiffies_to_msecs(delay) > 50)) {
-                        w->private = NULL;
-
-                        closure_delay(&dc->writeback, delay);
-                        continue_at(cl, read_dirty, dirty_wq);
-                }
+                     jiffies_to_msecs(delay) > 50))
+                        delay = schedule_timeout_uninterruptible(delay);
 
                 dc->last_read   = KEY_OFFSET(&w->key);
 
@@ -424,15 +422,10 @@ static void read_dirty(struct closure *cl)
 
                 trace_bcache_writeback(&w->key);
 
-                closure_call(&io->cl, read_dirty_submit, NULL, &dc->disk.cl);
+                down(&dc->in_flight);
+                closure_call(&io->cl, read_dirty_submit, NULL, cl);
 
                 delay = writeback_delay(dc, KEY_SIZE(&w->key));
-
-                atomic_inc(&dc->in_flight);
-
-                if (!closure_wait_event(&dc->writeback_wait, cl,
-                                        atomic_read(&dc->in_flight) < 64))
-                        continue_at(cl, read_dirty, dirty_wq);
         }
 
         if (0) {
@@ -442,7 +435,11 @@ err:
                 bch_keybuf_del(&dc->writeback_keys, w);
         }
 
-        refill_dirty(cl);
+        /*
+         * Wait for outstanding writeback IOs to finish (and keybuf slots to be
+         * freed) before refilling again
+         */
+        continue_at(cl, refill_dirty, dirty_wq);
 }
 
 /* Init */
@@ -484,6 +481,7 @@ void bch_sectors_dirty_init(struct cached_dev *dc)
 
 void bch_cached_dev_writeback_init(struct cached_dev *dc)
 {
+        sema_init(&dc->in_flight, 64);
         closure_init_unlocked(&dc->writeback);
         init_rwsem(&dc->writeback_lock);
 
@@ -513,7 +511,7 @@ void bch_writeback_exit(void)
 
 int __init bch_writeback_init(void)
 {
-        dirty_wq = create_singlethread_workqueue("bcache_writeback");
+        dirty_wq = create_workqueue("bcache_writeback");
         if (!dirty_wq)
                 return -ENOMEM;