bcachefs: Replace zero-length arrays with flexible-array members

Fake flexible arrays (zero-length and one-element arrays) are
deprecated, and should be replaced by flexible-array members.

So, replace zero-length arrays with flexible-array members
in multiple structures.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bcachefs_ioctl.h

@@ -276,7 +276,7 @@ struct bch_ioctl_fs_usage {
 	__u32			replica_entries_bytes;
 	__u32			pad;
 
-	struct bch_replicas_usage replicas[0];
+	struct bch_replicas_usage replicas[];
 };
 
 /*
@@ -313,7 +313,7 @@ struct bch_ioctl_dev_usage_v2 {
 	__u32			bucket_size;
 	__u64			nr_buckets;
 
-	struct bch_ioctl_dev_usage_type  d[0];
+	struct bch_ioctl_dev_usage_type d[];
 };
 
 /*

fs/bcachefs/io_read.c

@@ -80,7 +80,7 @@ struct promote_op {
 	struct bpos		pos;
 
 	struct data_update	write;
-	struct bio_vec		bi_inline_vecs[0]; /* must be last */
+	struct bio_vec		bi_inline_vecs[]; /* must be last */
 };
 
 static const struct rhashtable_params bch_promote_params = {

fs/bcachefs/move.c

@@ -70,7 +70,7 @@ struct moving_io {
 
 	struct data_update		write;
 	/* Must be last since it is variable size */
-	struct bio_vec			bi_inline_vecs[0];
+	struct bio_vec			bi_inline_vecs[];
 };
 
 static void move_free(struct moving_io *io)

fs/bcachefs/replicas_types.h

@@ -21,7 +21,7 @@ struct replicas_delta_list {
 	u64			nr_inodes;
 	u64			persistent_reserved[BCH_REPLICAS_MAX];
 	struct			{} memset_end;
-	struct replicas_delta	d[0];
+	struct replicas_delta	d[];
 };
 
 #endif /* _BCACHEFS_REPLICAS_TYPES_H */