[PATCH v2 10/17] bcache: handle c->uuids properly for bucket size > 8MB

Coly Li
2020-07-15T05:46:43Z

Bcache allocates a whole bucket to store c->uuids on cache device, and
allocates continuous pages to store it in-memory. When the bucket size
exceeds maximum allocable continuous pages, bch_cache_set_alloc() will
fail and cache device registration will fail.

This patch allocates c->uuids by alloc_meta_bucket_pages(), and uses
ilog2(meta_bucket_pages(c)) to indicate order of c->uuids pages when
free it. When writing c->uuids to cache device, its size is decided
by meta_bucket_pages(c) * PAGE_SECTORS. Now c->uuids is properly handled
for bucket size > 8MB.

Signed-off-by: Coly Li <colyli@suse.de>
---
drivers/md/bcache/super.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 73086cf6a2f3..9e1f2f529fc3 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -466,6 +466,7 @@ static int __uuid_write(struct cache_set *c)
BKEY_PADDED(key) k;
struct closure cl;
struct cache *ca;
+ unsigned int size;

closure_init_stack(&cl);
lockdep_assert_held(&bch_register_lock);
@@ -473,7 +474,8 @@ static int __uuid_write(struct cache_set *c)
if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true))
return 1;

- SET_KEY_SIZE(&k.key, c->sb.bucket_size);
+ size = meta_bucket_pages(&c->sb) * PAGE_SECTORS;
+ SET_KEY_SIZE(&k.key, size);
uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl);
closure_sync(&cl);

@@ -1656,7 +1658,7 @@ static void cache_set_free(struct closure *cl)
}

bch_bset_sort_state_free(&c->sort);
- free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c)));
+ free_pages((unsigned long) c->uuids, ilog2(meta_bucket_pages(&c->sb)));

if (c->moving_gc_wq)
destroy_workqueue(c->moving_gc_wq);
@@ -1862,7 +1864,7 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)

c->bucket_bits = ilog2(sb->bucket_size);
c->block_bits = ilog2(sb->block_size);
- c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry);
+ c->nr_uuids = meta_bucket_bytes(&c->sb) / sizeof(struct uuid_entry);
c->devices_max_used = 0;
atomic_set(&c->attached_dev_nr, 0);
c->btree_pages = bucket_pages(c);
@@ -1913,7 +1915,7 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
goto err;

- c->uuids = alloc_bucket_pages(GFP_KERNEL, c);
+ c->uuids = alloc_meta_bucket_pages(GFP_KERNEL, &c->sb);
if (!c->uuids)
goto err;

--
2.26.2