bcache: handle cache prio_buckets and disk_buckets properly for bucket size > 8MB
Similar to c->uuids, struct cache's prio_buckets and disk_buckets also
have the potential memory allocation failure during cache registration
if the bucket size > 8MB.
ca->prio_buckets can be stored on cache device in multiple buckets, its
in-memory space is allocated by kzalloc() interface but normally
allocated by alloc_pages() because the size > KMALLOC_MAX_CACHE_SIZE.
So allocation of ca->prio_buckets has the MAX_ORDER restriction too. If
the bucket size > 8MB, by default the page allocator will fail because
the page order > 11 (default MAX_ORDER value). ca->prio_buckets should
also use meta_bucket_bytes(), meta_bucket_pages() to decide its memory
size and use alloc_meta_bucket_pages() to allocate pages, to avoid the
allocation failure during cache set registration when bucket size > 8MB.
ca->disk_buckets is a single bucket size memory buffer, it is used to
iterate each bucket of ca->prio_buckets, and compose the bio based on
memory of ca->disk_buckets, then write ca->disk_buckets memory to cache
disk one-by-one for each bucket of ca->prio_buckets. ca->disk_buckets
should have in-memory size exact to the meta_bucket_pages(), this is the
size that ca->prio_buckets will be stored into each on-disk bucket.
This patch fixes the above issues and handle cache's prio_buckets and
disk_buckets properly for bucket size larger than 8MB.
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 5e1c581..4fd03d2 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -782,11 +782,12 @@ static inline unsigned int meta_bucket_bytes(struct cache_sb *sb)
return meta_bucket_pages(sb) << PAGE_SHIFT;
}
-#define prios_per_bucket(c) \
- ((bucket_bytes(c) - sizeof(struct prio_set)) / \
+#define prios_per_bucket(ca) \
+ ((meta_bucket_bytes(&(ca)->sb) - sizeof(struct prio_set)) / \
sizeof(struct bucket_disk))
-#define prio_buckets(c) \
- DIV_ROUND_UP((size_t) (c)->sb.nbuckets, prios_per_bucket(c))
+
+#define prio_buckets(ca) \
+ DIV_ROUND_UP((size_t) (ca)->sb.nbuckets, prios_per_bucket(ca))
static inline size_t sector_to_bucket(struct cache_set *c, sector_t s)
{
