bcachefs: Zero out reflink_p val in bch2_make_extent_indirect()

This bug was only discovered when we started using the 2nd word in the
val, which should have been zeroed out as those fields had never been
used before - ouch.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

diff --git a/fs/bcachefs/reflink.c b/fs/bcachefs/reflink.c
index 92ff609453b8349e3ce6a25277bcaeece461d388..c63c95fc49b1aefb689fd76e8bf783f88ca72b8b 100644 (file)
--- a/fs/bcachefs/reflink.c
+++ b/fs/bcachefs/reflink.c
@@ -166,9 +166,15 @@ static int bch2_make_extent_indirect(struct btree_trans *trans,
        if (ret)
                goto err;
 
+       /*
+        * orig is in a bkey_buf which statically allocates 5 64s for the val,
+        * so we know it will be big enough:
+        */
        orig->k.type = KEY_TYPE_reflink_p;
        r_p = bkey_i_to_reflink_p(orig);
        set_bkey_val_bytes(&r_p->k, sizeof(r_p->v));
+       memset(&r_p->v, 0, sizeof(r_p->v));
+
        r_p->v.idx = cpu_to_le64(bkey_start_offset(&r_v->k));
 
        ret = bch2_trans_update(trans, extent_iter, &r_p->k_i, 0);