bcachefs: Annotate bch_replicas_entry_{v0,v1} with __counted_by()

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

Increment nr_devs before adding a new device to the devs array and
adjust the array indexes accordingly. Add a helper macro for adding a
new device.

In bch2_journal_read(), explicitly set nr_devs to 0.

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/bcachefs/journal_io.c b/fs/bcachefs/journal_io.c
index 32b886feb2ca..30460bce04be 100644
--- a/fs/bcachefs/journal_io.c
+++ b/fs/bcachefs/journal_io.c
@@ -1353,6 +1353,7 @@ int bch2_journal_read(struct bch_fs *c,
 	genradix_for_each(&c->journal_entries, radix_iter, _i) {
 		struct bch_replicas_padded replicas = {
 			.e.data_type = BCH_DATA_journal,
+			.e.nr_devs = 0,
 			.e.nr_required = 1,
 		};
 
@@ -1379,7 +1380,7 @@ int bch2_journal_read(struct bch_fs *c,
 			goto err;
 
 		darray_for_each(i->ptrs, ptr)
-			replicas.e.devs[replicas.e.nr_devs++] = ptr->dev;
+			replicas_entry_add_dev(&replicas.e, ptr->dev);
 
 		bch2_replicas_entry_sort(&replicas.e);