bcachefs: Reflink refcount fix

__bch2_trans_mark_reflink_p wasn't always correctly returning the number
of sectors processed - the new logic is a bit more straightforward
overall too.

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

diff --git a/fs/bcachefs/buckets.c b/fs/bcachefs/buckets.c
index 6389ec7ba18b065a408ddade4c78a2d91a5eab4d..b452ff003e6c69e0c9dd1b28fd5b517734a32ac9 100644 (file)
--- a/fs/bcachefs/buckets.c
+++ b/fs/bcachefs/buckets.c
@@ -1735,6 +1735,7 @@ static int __bch2_trans_mark_reflink_p(struct btree_trans *trans,
        struct bkey_i *n;
        __le64 *refcount;
        int add = !(flags & BTREE_TRIGGER_OVERWRITE) ? 1 : -1;
+       int frags_referenced;
        s64 ret;
 
        ret = trans_get_key(trans, BTREE_ID_reflink,
@@ -1742,18 +1743,20 @@ static int __bch2_trans_mark_reflink_p(struct btree_trans *trans,
        if (ret < 0)
                return ret;
 
-       if (reflink_p_frag_references(p, 0, front_frag, k) &&
-           reflink_p_frag_references(p, back_frag, p.k->size, k)) {
+       sectors = min_t(u64, sectors, k.k->p.offset - idx);
+
+       frags_referenced =
+               reflink_p_frag_references(p, 0, front_frag, k) +
+               reflink_p_frag_references(p, back_frag, p.k->size, k);
+
+       if (frags_referenced == 2) {
                BUG_ON(!(flags & BTREE_TRIGGER_OVERWRITE_SPLIT));
                add = -add;
-       } else if (reflink_p_frag_references(p, 0, front_frag, k) ||
-                  reflink_p_frag_references(p, back_frag, p.k->size, k)) {
+       } else if (frags_referenced == 1) {
                BUG_ON(!(flags & BTREE_TRIGGER_OVERWRITE));
                goto out;
        }
 
-       sectors = min_t(u64, sectors, k.k->p.offset - idx);
-
        n = bch2_trans_kmalloc(trans, bkey_bytes(k.k));
        ret = PTR_ERR_OR_ZERO(n);
        if (ret)
@@ -1808,14 +1811,13 @@ static int bch2_trans_mark_reflink_p(struct btree_trans *trans,
                ret = __bch2_trans_mark_reflink_p(trans, p, idx, sectors,
                                        front_frag, back_frag, flags);
                if (ret < 0)
-                       break;
+                       return ret;
 
-               idx += ret;
-               sectors = max_t(s64, 0LL, sectors - ret);
-               ret = 0;
+               idx     += ret;
+               sectors -= ret;
        }
 
-       return ret;
+       return 0;
 }
 
 int bch2_trans_mark_key(struct btree_trans *trans,