Commit 901ff655 authored by Thorsten Blum's avatar Thorsten Blum Committed by Kent Overstreet
Browse files

bcachefs: Annotate struct bucket_gens with __counted_by() 



Add the __counted_by compiler attribute to the flexible array member b
to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and
CONFIG_FORTIFY_SOURCE.

Use struct_size() to calculate the number of bytes to be allocated.

Update bucket_gens->nbuckets and bucket_gens->nbuckets_minus_first when
resizing.

Compile-tested only.

Signed-off-by: default avatarThorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent ac9826f1

fs/bcachefs/buckets.c

+8 −5
Original line number Diff line number Diff line
@@ -1266,8 +1266,9 @@ int bch2_dev_buckets_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets) 


	BUG_ON(resize && ca->buckets_nouse);



	if (!(bucket_gens	= kvmalloc(sizeof(struct bucket_gens) + nbuckets,

					   GFP_KERNEL|__GFP_ZERO))) {

	bucket_gens = kvmalloc(struct_size(bucket_gens, b, nbuckets),

			       GFP_KERNEL|__GFP_ZERO);

	if (!bucket_gens) {

		ret = -BCH_ERR_ENOMEM_bucket_gens;

		goto err;

	}
@@ -1285,11 +1286,13 @@ int bch2_dev_buckets_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets) 
	old_bucket_gens = rcu_dereference_protected(ca->bucket_gens, 1);



	if (resize) {

		size_t n = min(bucket_gens->nbuckets, old_bucket_gens->nbuckets);



		bucket_gens->nbuckets = min(bucket_gens->nbuckets,

					    old_bucket_gens->nbuckets);

		bucket_gens->nbuckets_minus_first =

			bucket_gens->nbuckets - bucket_gens->first_bucket;

		memcpy(bucket_gens->b,

		       old_bucket_gens->b,

		       n);

		       bucket_gens->nbuckets);

	}



	rcu_assign_pointer(ca->bucket_gens, bucket_gens);

fs/bcachefs/buckets_types.h

+1 −1
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ struct bucket_gens { 
	u16			first_bucket;

	size_t			nbuckets;

	size_t			nbuckets_minus_first;

	u8			b[];

	u8			b[] __counted_by(nbuckets);

};



struct bch_dev_usage {