bcache: ver 3

help
<some explanatory help text>
please. The tristate prompt didn't do anything for me.

Quoted 3 lines · Randy Dunlap

help
<some explanatory help text>
please. The tristate prompt didn't do anything for me.

Did the prompt not show up at all? That's odd, I wouldn't have thought help text would have anything to do with that - I just added help to the kconfig, though. I'll have it up in a git repository soon, I don't suppose I should be posting a 2.4k line patch multiple times per day...

Quoted 5 lines · Kent Overstreet

Quoted 3 lines · Randy Dunlap

help
<some explanatory help text>
please. The tristate prompt didn't do anything for me.

Quoted 4 lines

Did the prompt not show up at all? That's odd, I wouldn't have thought help text would have anything to do with that - I just added help to the kconfig, though. I'll have it up in a git repository soon, I don't suppose I should be posting a 2.4k line patch multiple times per day...

I'm just saying that it needs help text -- the prompt doesn't say enough.

 block/Kconfig       |    5 +
 block/Makefile      |    2 +
 block/bcache.c      | 2337 +++++++++++++++++++++++++++++++++++++++++++++++++++
 block/blk-core.c    |    7 +-
 fs/bio.c            |   32 +-
 include/linux/bio.h |    2 +
 include/linux/fs.h  |    5 +
 7 files changed, 2386 insertions(+), 4 deletions(-)

block/bcache.c new file +0 -0

new file mode 100644
index 0000000..3bf3fff

block/bcache.c new file +17 -0

+		if (c->devices[dev] == bio->bi_bdev->bd_cache_identifier)
+			break;
+
+	if (dev == 256)
+		printk(KERN_DEBUG "bcache: unknown device %i",
+		       bio->bi_bdev->bd_cache_identifier);
+
+	return dev;
+}
 
 
+static void register_dev(const char *buffer, size_t size)
+{
+	int i;
+	char *path;
+	unsigned char uuid[16];
+	struct block_device *bdev;
+	struct list_head *l;
+

block/bcache.c new file +22 -0

+		return;
+	}
+	strcpy(path, skip_spaces(buffer + i));
+	bdev = lookup_bdev(strim(path));
+
+	if (IS_ERR(bdev)) {
+		printk(KERN_DEBUG "bcache: Failed to open %s", path);
+		goto out;
+	}
+
+	for (i = 0; i < 256; i++) {
+		if (is_zero(&uuids[i*16], 16))
+			break;
+
+		if (!memcmp(&uuids[i*16], uuid, 16)) {
+			printk(KERN_DEBUG "bcache: %s already registered", path);
+			bdput(bdev);
+			goto out;
+		}
+	}
+	memcpy(&uuids[i*16], uuid, 16);
+	bdev->bd_cache_identifier = i;

block/bcache.c new file +68 -0

+static ssize_t show_cache(struct kobject *kobj, struct attribute *attr,
+			  char *buffer)
+{
+	struct cache_device *c = container_of(kobj, struct cache_device, kobj);
+
+	sysfs_print(bucket_size, "%i\n", c->sb.bucket_size << 9);
+	sysfs_print(buckets_used, "%lli\n", c->sb.first_free_bucket);
+	sysfs_print(buckets_free, "%lli\n", c->sb.nbuckets -
+		    c->sb.first_free_bucket);
+	sysfs_print(nbuckets,	"%lli\n", c->sb.nbuckets);
+	sysfs_print(cache_hits, "%lu\n", c->cache_hits);
+	sysfs_print(tree_depth, "%u\n", c->sb.btree_level);
+	sysfs_print(min_priority, "%u\n", c->heap[0] ? c->heap[0]->priority : 0);
+	return 0;
+}
 
 
+static void register_cache(const char *buffer, size_t size)
+{
+	char *err = NULL, *path, b[BDEVNAME_SIZE];
+	int i;
+	struct cache_device *c;
+	struct search_context s, *sp = &s;
+
+	static struct attribute *files[] = {
+		&sysfs_unregister,
+		&sysfs_bucket_size,
+		&sysfs_buckets_used,
+		&sysfs_buckets_free,
+		&sysfs_nbuckets,
+		&sysfs_cache_hits,
+		&sysfs_tree_depth,
+		&sysfs_min_priority,
+		NULL
+	};
+	static const struct sysfs_ops ops = {
+		.show = show_cache,
+		.store = store_cache
+	};
+	static struct kobj_type cache_obj = {
+		.release = unregister_cache,
+		.sysfs_ops = &ops,
+		.default_attrs = files
+	};
+
+	if (!try_module_get(THIS_MODULE))
+		return;
+
+	path = kmalloc(size + 1, GFP_KERNEL);
+	strcpy(path, skip_spaces(buffer));
+
+	err = "Insufficient memory";
+	if (!(c = kzalloc(sizeof(*c), GFP_KERNEL)))
+		goto err;
+
+	err = "Failed to open cache device";
+	c->bdev = open_bdev_exclusive(strim(path), FMODE_READ|FMODE_WRITE, c);
+	if (IS_ERR(c->bdev)) {
+		if (c->bdev == ERR_PTR(EBUSY))
+			err = "Device busy";
+		goto err;
+	}
+
+	set_blocksize(c->bdev, 4096);
+
+	err = "IO error";
+	if (!(c->sb_bh = __bread(c->bdev, 1, PAGE_SIZE)))
+		goto err;
+
+	if (!(c->uuids = __bread(c->bdev, 2, PAGE_SIZE)))

block/bcache.c new file +62 -0

+	c->heap		= vmalloc(c->sb.nbuckets * sizeof(struct bucket *));
+	c->buckets	= vmalloc(c->sb.nbuckets * sizeof(struct bucket));
+	c->freelist	= vmalloc(c->free_size-- * sizeof(long));
+	if (!c->heap || !c->buckets || !c->freelist)
+		goto err;
+
+	memset(c->heap,	   0, c->sb.nbuckets * sizeof(struct bucket *));
+	memset(c->buckets, 0, c->sb.nbuckets * sizeof(struct bucket));
+
+	spin_lock_init(&c->bucket_lock);
+	spin_lock_init(&c->alloc_lock);
+	init_rwsem(&c->gc_lock);
+
+	INIT_LIST_HEAD(&c->lru);
+	c->btree_buckets_cached = 10;
+
+	load_priorities(c);
+
+	memset(&s, 0, sizeof(s));
+	c->root = get_bucket(c, c->sb.btree_root, c->sb.btree_level, false, &sp);
+	c->buckets[sector_to_bucket(c->root->offset)].priority = ~0;
+
+	list_del(&c->root->lru);
+	rw_unlock(false, &c->root->lock);
+
+	/*for (i = 0; i < 256 && devices[i]; i++)
+		register_dev_on_cache(c, i);*/
+
+	for (i = 0; i < 256; i++)
+		c->devices[i] = ~0;
+
+	for (i = 0; i < 256 && !is_zero(&uuids[i*16], 16); i++)
+		register_dev_on_cache(c, i);
+
+	err = "kobject create error";
+	bdevname(c->bdev, b);
+	if (!kobject_get(bcache_kobj))
+		goto err;
+
+	if (kobject_init_and_add(&c->kobj, &cache_obj,
+				 bcache_kobj,
+				 "%s", b))
+		goto err;
+
+	list_add(&c->list, &cache_devices);
+
+	printk(KERN_DEBUG "bcache: Loaded cache device %s, pages_per_btree %i, keys_per_page %li",
+	       path, pages_per_btree, keys_per_page);
+	kfree(path);
+	return;
+err:
+	if (c) {
+		if (c->sb_bh)
+			put_bh(c->sb_bh);
+		if (c->uuids)
+			put_bh(c->uuids);
+		if (c->kobj.state_initialized)
+			kobject_put(&c->kobj);
+		if (c->freelist)
+			vfree(c->freelist);
+		if (c->buckets)
+			vfree(c->buckets);

Quoted 1 line

+#define label(l, foo) if (0) { l: foo; }

I'd prefer that macro to go away.

block/bcache.c line 234

Quoted 1 line

block/bcache.c new file +1 -0

+	return d[i / keys_per_page] + (i % keys_per_page);

That builds OK on i386? or does it need udivdi3() and/or umoddi3()?

block/bcache.c

Quoted 7 lines

block/bcache.c new file +5 -0

+}
 
+static int lookup_dev(struct cache_device *c, struct bio *bio)
+{
+	int dev;
+	for (dev = 0; dev<  256; dev++)

Use a macro for 256.. in lots of places.

bcache: cannot allocate memory
"kmalloc error" sounds like kmalloc() had an internal error.

Need to document the sysfs interfaces:

block/bcache.c line 2168

Quoted 1 line

block/bcache.c new file +1 -0

+	err = "vmalloc error";

		"cannot vmalloc memory";