bcache: Fix error handling in init code

This code appears to have rotted... fix various bugs and do some
refactoring.

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

4 files changed, 99 insertions, 121 deletions

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 340146d7c17f..d3e15b42a4ab 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -1241,7 +1241,7 @@ 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_writeback_init_cached_dev(struct cached_dev *);
+void bch_cached_dev_writeback_init(struct cached_dev *);
 void bch_moving_init_cache_set(struct cache_set *);
 
 void bch_cache_allocator_exit(struct cache *ca);
diff --git a/drivers/md/bcache/stats.c b/drivers/md/bcache/stats.c
index 64e679449c2a..b8730e714d69 100644
--- a/drivers/md/bcache/stats.c
+++ b/drivers/md/bcache/stats.c
@@ -93,24 +93,6 @@ static struct attribute *bch_stats_files[] = {
 };
 static KTYPE(bch_stats);
 
-static void scale_accounting(unsigned long data);
-
-void bch_cache_accounting_init(struct cache_accounting *acc,
-                               struct closure *parent)
-{
-        kobject_init(&acc->total.kobj,          &bch_stats_ktype);
-        kobject_init(&acc->five_minute.kobj,    &bch_stats_ktype);
-        kobject_init(&acc->hour.kobj,           &bch_stats_ktype);
-        kobject_init(&acc->day.kobj,            &bch_stats_ktype);
-
-        closure_init(&acc->cl, parent);
-        init_timer(&acc->timer);
-        acc->timer.expires      = jiffies + accounting_delay;
-        acc->timer.data         = (unsigned long) acc;
-        acc->timer.function     = scale_accounting;
-        add_timer(&acc->timer);
-}
-
 int bch_cache_accounting_add_kobjs(struct cache_accounting *acc,
                                    struct kobject *parent)
 {
@@ -244,3 +226,19 @@ void bch_mark_sectors_bypassed(struct search *s, int sectors)
         atomic_add(sectors, &dc->accounting.collector.sectors_bypassed);
         atomic_add(sectors, &s->op.c->accounting.collector.sectors_bypassed);
 }
+
+void bch_cache_accounting_init(struct cache_accounting *acc,
+                               struct closure *parent)
+{
+        kobject_init(&acc->total.kobj,          &bch_stats_ktype);
+        kobject_init(&acc->five_minute.kobj,    &bch_stats_ktype);
+        kobject_init(&acc->hour.kobj,           &bch_stats_ktype);
+        kobject_init(&acc->day.kobj,            &bch_stats_ktype);
+
+        closure_init(&acc->cl, parent);
+        init_timer(&acc->timer);
+        acc->timer.expires      = jiffies + accounting_delay;
+        acc->timer.data         = (unsigned long) acc;
+        acc->timer.function     = scale_accounting;
+        add_timer(&acc->timer);
+}
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index b09beb2b52c7..f88e2b653a3f 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -731,8 +731,7 @@ static void bcache_device_free(struct bcache_device *d)
 
         if (d->c)
                 bcache_device_detach(d);
-
-        if (d->disk)
+        if (d->disk && d->disk->flags & GENHD_FL_UP)
                 del_gendisk(d->disk);
         if (d->disk && d->disk->queue)
                 blk_cleanup_queue(d->disk->queue);
@@ -755,12 +754,9 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size)
         if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
             !(d->unaligned_bvec = mempool_create_kmalloc_pool(1,
                                 sizeof(struct bio_vec) * BIO_MAX_PAGES)) ||
-            bio_split_pool_init(&d->bio_split_hook))
-
-                return -ENOMEM;
-
-        d->disk = alloc_disk(1);
-        if (!d->disk)
+            bio_split_pool_init(&d->bio_split_hook) ||
+            !(d->disk = alloc_disk(1)) ||
+            !(q = blk_alloc_queue(GFP_KERNEL)))
                 return -ENOMEM;
 
         snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", bcache_minor);
@@ -770,10 +766,6 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size)
         d->disk->fops           = &bcache_ops;
         d->disk->private_data   = d;
 
-        q = blk_alloc_queue(GFP_KERNEL);
-        if (!q)
-                return -ENOMEM;
-
         blk_queue_make_request(q, NULL);
         d->disk->queue                  = q;
         q->queuedata                    = d;
@@ -998,14 +990,17 @@ static void cached_dev_free(struct closure *cl)
 
         mutex_lock(&bch_register_lock);
 
-        bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
+        if (atomic_read(&dc->running))
+                bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
         bcache_device_free(&dc->disk);
         list_del(&dc->list);
 
         mutex_unlock(&bch_register_lock);
 
         if (!IS_ERR_OR_NULL(dc->bdev)) {
-                blk_sync_queue(bdev_get_queue(dc->bdev));
+                if (dc->bdev->bd_disk)
+                        blk_sync_queue(bdev_get_queue(dc->bdev));
+
                 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
         }
 
@@ -1027,73 +1022,67 @@ static void cached_dev_flush(struct closure *cl)
 
 static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
 {
-        int err;
+        int ret;
         struct io *io;
-
-        closure_init(&dc->disk.cl, NULL);
-        set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
+        struct request_queue *q = bdev_get_queue(dc->bdev);
 
         __module_get(THIS_MODULE);
         INIT_LIST_HEAD(&dc->list);
+        closure_init(&dc->disk.cl, NULL);
+        set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
         kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
-
-        bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
-
-        err = bcache_device_init(&dc->disk, block_size);
-        if (err)
-                goto err;
-
-        spin_lock_init(&dc->io_lock);
-        closure_init_unlocked(&dc->sb_write);
         INIT_WORK(&dc->detach, cached_dev_detach_finish);
+        closure_init_unlocked(&dc->sb_write);
+        INIT_LIST_HEAD(&dc->io_lru);
+        spin_lock_init(&dc->io_lock);
+        bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
 
         dc->sequential_merge            = true;
         dc->sequential_cutoff           = 4 << 20;
 
-        INIT_LIST_HEAD(&dc->io_lru);
-        dc->sb_bio.bi_max_vecs  = 1;
-        dc->sb_bio.bi_io_vec    = dc->sb_bio.bi_inline_vecs;
-
         for (io = dc->io; io < dc->io + RECENT_IO; io++) {
                 list_add(&io->lru, &dc->io_lru);
                 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
         }
 
-        bch_writeback_init_cached_dev(dc);
+        ret = bcache_device_init(&dc->disk, block_size);
+        if (ret)
+                return ret;
+
+        set_capacity(dc->disk.disk,
+                     dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
+
+        dc->disk.disk->queue->backing_dev_info.ra_pages =
+                max(dc->disk.disk->queue->backing_dev_info.ra_pages,
+                    q->backing_dev_info.ra_pages);
+
+        bch_cached_dev_request_init(dc);
+        bch_cached_dev_writeback_init(dc);
         return 0;
-err:
-        bcache_device_stop(&dc->disk);
-        return err;
 }
 
 /* Cached device - bcache superblock */
 
-static const char *register_bdev(struct cache_sb *sb, struct page *sb_page,
+static void register_bdev(struct cache_sb *sb, struct page *sb_page,
                                  struct block_device *bdev,
                                  struct cached_dev *dc)
 {
         char name[BDEVNAME_SIZE];
         const char *err = "cannot allocate memory";
-        struct gendisk *g;
         struct cache_set *c;
 
-        if (!dc || cached_dev_init(dc, sb->block_size << 9) != 0)
-                return err;
-
         memcpy(&dc->sb, sb, sizeof(struct cache_sb));
-        dc->sb_bio.bi_io_vec[0].bv_page = sb_page;
         dc->bdev = bdev;
         dc->bdev->bd_holder = dc;
 
-        g = dc->disk.disk;
-
-        set_capacity(g, dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
-
-        g->queue->backing_dev_info.ra_pages =
-                max(g->queue->backing_dev_info.ra_pages,
-                    bdev->bd_queue->backing_dev_info.ra_pages);
+        bio_init(&dc->sb_bio);
+        dc->sb_bio.bi_max_vecs  = 1;
+        dc->sb_bio.bi_io_vec    = dc->sb_bio.bi_inline_vecs;
+        dc->sb_bio.bi_io_vec[0].bv_page = sb_page;
+        get_page(sb_page);
 
-        bch_cached_dev_request_init(dc);
+        if (cached_dev_init(dc, sb->block_size << 9))
+                goto err;
 
         err = "error creating kobject";
         if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
@@ -1102,6 +1091,8 @@ static const char *register_bdev(struct cache_sb *sb, struct page *sb_page,
         if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
                 goto err;
 
+        pr_info("registered backing device %s", bdevname(bdev, name));
+
         list_add(&dc->list, &uncached_devices);
         list_for_each_entry(c, &bch_cache_sets, list)
                 bch_cached_dev_attach(dc, c);
@@ -1110,15 +1101,10 @@ static const char *register_bdev(struct cache_sb *sb, struct page *sb_page,
             BDEV_STATE(&dc->sb) == BDEV_STATE_STALE)
                 bch_cached_dev_run(dc);
 
-        return NULL;
+        return;
 err:
-        kobject_put(&dc->disk.kobj);
         pr_notice("error opening %s: %s", bdevname(bdev, name), err);
-        /*
-         * Return NULL instead of an error because kobject_put() cleans
-         * everything up
-         */
-        return NULL;
+        bcache_device_stop(&dc->disk);
 }
 
 /* Flash only volumes */
@@ -1716,20 +1702,11 @@ static int cache_alloc(struct cache_sb *sb, struct cache *ca)
         size_t free;
         struct bucket *b;
 
-        if (!ca)
-                return -ENOMEM;
-
         __module_get(THIS_MODULE);
         kobject_init(&ca->kobj, &bch_cache_ktype);
 
-        memcpy(&ca->sb, sb, sizeof(struct cache_sb));
-
         INIT_LIST_HEAD(&ca->discards);
 
-        bio_init(&ca->sb_bio);
-        ca->sb_bio.bi_max_vecs  = 1;
-        ca->sb_bio.bi_io_vec    = ca->sb_bio.bi_inline_vecs;
-
         bio_init(&ca->journal.bio);
         ca->journal.bio.bi_max_vecs = 8;
         ca->journal.bio.bi_io_vec = ca->journal.bio.bi_inline_vecs;
@@ -1741,18 +1718,17 @@ static int cache_alloc(struct cache_sb *sb, struct cache *ca)
             !init_fifo(&ca->free_inc,   free << 2, GFP_KERNEL) ||
             !init_fifo(&ca->unused,     free << 2, GFP_KERNEL) ||
             !init_heap(&ca->heap,       free << 3, GFP_KERNEL) ||
-            !(ca->buckets       = vmalloc(sizeof(struct bucket) *
+            !(ca->buckets       = vzalloc(sizeof(struct bucket) *
                                           ca->sb.nbuckets)) ||
             !(ca->prio_buckets  = kzalloc(sizeof(uint64_t) * prio_buckets(ca) *
                                           2, GFP_KERNEL)) ||
             !(ca->disk_buckets  = alloc_bucket_pages(GFP_KERNEL, ca)) ||
             !(ca->alloc_workqueue = alloc_workqueue("bch_allocator", 0, 1)) ||
             bio_split_pool_init(&ca->bio_split_hook))
-                goto err;
+                return -ENOMEM;
 
         ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
 
-        memset(ca->buckets, 0, ca->sb.nbuckets * sizeof(struct bucket));
         for_each_bucket(b, ca)
                 atomic_set(&b->pin, 0);
 
@@ -1765,22 +1741,28 @@ err:
         return -ENOMEM;
 }
 
-static const char *register_cache(struct cache_sb *sb, struct page *sb_page,
+static void register_cache(struct cache_sb *sb, struct page *sb_page,
                                   struct block_device *bdev, struct cache *ca)
 {
         char name[BDEVNAME_SIZE];
         const char *err = "cannot allocate memory";
 
-        if (cache_alloc(sb, ca) != 0)
-                return err;
-
-        ca->sb_bio.bi_io_vec[0].bv_page = sb_page;
+        memcpy(&ca->sb, sb, sizeof(struct cache_sb));
         ca->bdev = bdev;
         ca->bdev->bd_holder = ca;
 
+        bio_init(&ca->sb_bio);
+        ca->sb_bio.bi_max_vecs  = 1;
+        ca->sb_bio.bi_io_vec    = ca->sb_bio.bi_inline_vecs;
+        ca->sb_bio.bi_io_vec[0].bv_page = sb_page;
+        get_page(sb_page);
+
         if (blk_queue_discard(bdev_get_queue(ca->bdev)))
                 ca->discard = CACHE_DISCARD(&ca->sb);
 
+        if (cache_alloc(sb, ca) != 0)
+                goto err;
+
         err = "error creating kobject";
         if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache"))
                 goto err;
@@ -1790,15 +1772,10 @@ static const char *register_cache(struct cache_sb *sb, struct page *sb_page,
                 goto err;
 
         pr_info("registered cache device %s", bdevname(bdev, name));
-
-        return NULL;
+        return;
 err:
+        pr_notice("error opening %s: %s", bdevname(bdev, name), err);
         kobject_put(&ca->kobj);
-        pr_info("error opening %s: %s", bdevname(bdev, name), err);
-        /* Return NULL instead of an error because kobject_put() cleans
-         * everything up
-         */
-        return NULL;
 }
 
 /* Global interfaces/init */
@@ -1832,12 +1809,15 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
         bdev = blkdev_get_by_path(strim(path),
                                   FMODE_READ|FMODE_WRITE|FMODE_EXCL,
                                   sb);
-        if (bdev == ERR_PTR(-EBUSY))
-                err = "device busy";
-
-        if (IS_ERR(bdev) ||
-            set_blocksize(bdev, 4096))
+        if (IS_ERR(bdev)) {
+                if (bdev == ERR_PTR(-EBUSY))
+                        err = "device busy";
                 goto err;
+        }
+
+        err = "failed to set blocksize";
+        if (set_blocksize(bdev, 4096))
+                goto err_close;
 
         err = read_super(sb, bdev, &sb_page);
         if (err)
@@ -1845,33 +1825,33 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 
         if (SB_IS_BDEV(sb)) {
                 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
+                if (!dc)
+                        goto err_close;
 
-                err = register_bdev(sb, sb_page, bdev, dc);
+                register_bdev(sb, sb_page, bdev, dc);
         } else {
                 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
+                if (!ca)
+                        goto err_close;
 
-                err = register_cache(sb, sb_page, bdev, ca);
+                register_cache(sb, sb_page, bdev, ca);
         }
-
-        if (err) {
-                /* register_(bdev|cache) will only return an error if they
-                 * didn't get far enough to create the kobject - if they did,
-                 * the kobject destructor will do this cleanup.
-                 */
+out:
+        if (sb_page)
                 put_page(sb_page);
-err_close:
-                blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
-err:
-                if (attr != &ksysfs_register_quiet)
-                        pr_info("error opening %s: %s", path, err);
-                ret = -EINVAL;
-        }
-
         kfree(sb);
         kfree(path);
         mutex_unlock(&bch_register_lock);
         module_put(THIS_MODULE);
         return ret;
+
+err_close:
+        blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
+err:
+        if (attr != &ksysfs_register_quiet)
+                pr_info("error opening %s: %s", path, err);
+        ret = -EINVAL;
+        goto out;
 }
 
 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 93e7e31a4bd3..2714ed3991d1 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -375,7 +375,7 @@ err:
         refill_dirty(cl);
 }
 
-void bch_writeback_init_cached_dev(struct cached_dev *dc)
+void bch_cached_dev_writeback_init(struct cached_dev *dc)
 {
         closure_init_unlocked(&dc->writeback);
         init_rwsem(&dc->writeback_lock);