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 (file)
--- 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)
 {

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 2ddc41c..b5ad481 100644 (file)
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -563,7 +563,7 @@ static void prio_io(struct cache *ca, uint64_t bucket, int op,
 
        bio->bi_iter.bi_sector  = bucket * ca->sb.bucket_size;
        bio_set_dev(bio, ca->bdev);
-       bio->bi_iter.bi_size    = bucket_bytes(ca);
+       bio->bi_iter.bi_size    = meta_bucket_bytes(&ca->sb);
 
        bio->bi_end_io  = prio_endio;
        bio->bi_private = ca;
@@ -621,7 +621,7 @@ int bch_prio_write(struct cache *ca, bool wait)
 
                p->next_bucket  = ca->prio_buckets[i + 1];
                p->magic        = pset_magic(&ca->sb);
-               p->csum         = bch_crc64(&p->magic, bucket_bytes(ca) - 8);
+               p->csum         = bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8);
 
                bucket = bch_bucket_alloc(ca, RESERVE_PRIO, wait);
                BUG_ON(bucket == -1);
@@ -674,7 +674,7 @@ static int prio_read(struct cache *ca, uint64_t bucket)
                        prio_io(ca, bucket, REQ_OP_READ, 0);
 
                        if (p->csum !=
-                           bch_crc64(&p->magic, bucket_bytes(ca) - 8)) {
+                           bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8)) {
                                pr_warn("bad csum reading priorities\n");
                                goto out;
                        }
@@ -2230,7 +2230,7 @@ void bch_cache_release(struct kobject *kobj)
                ca->set->cache[ca->sb.nr_this_dev] = NULL;
        }
 
-       free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
+       free_pages((unsigned long) ca->disk_buckets, ilog2(meta_bucket_pages(&ca->sb)));
        kfree(ca->prio_buckets);
        vfree(ca->buckets);
 
@@ -2327,7 +2327,7 @@ static int cache_alloc(struct cache *ca)
                goto err_prio_buckets_alloc;
        }
 
-       ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca);
+       ca->disk_buckets = alloc_meta_bucket_pages(GFP_KERNEL, &ca->sb);
        if (!ca->disk_buckets) {
                err = "ca->disk_buckets alloc failed";
                goto err_disk_buckets_alloc;