tdb2: add TDB_COALESCING_MAGIC to solve coalescing race.

[ccan-lca-2011.git] / ccan / tdb2 / check.c

diff --git a/ccan/tdb2/check.c b/ccan/tdb2/check.c
index eb8ddcae79baba5ba8f0fa8a5b4e908b4332f105..f3fff5f6b8e25a99b0d34682b92788a28ea48c6a 100644 (file)
--- a/ccan/tdb2/check.c
+++ b/ccan/tdb2/check.c
@@ -407,7 +407,8 @@ static tdb_off_t check_zone(struct tdb_context *tdb, tdb_off_t zone_off,
                p = tdb_get(tdb, off, &pad, sizeof(pad));
                if (!p)
                        return TDB_OFF_ERR;
-               if (frec_magic(&p->f) == TDB_FREE_MAGIC) {
+               if (frec_magic(&p->f) == TDB_FREE_MAGIC
+                   || frec_magic(&p->f) == TDB_COALESCING_MAGIC) {
                        if (frec_zone_bits(&p->f) != zhdr.zone_bits) {
                                tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
                                         "tdb_check: Bad free zone bits %u"
@@ -416,9 +417,6 @@ static tdb_off_t check_zone(struct tdb_context *tdb, tdb_off_t zone_off,
                                         (long long)off);
                                return TDB_OFF_ERR;
                        }
-                       /* This record is free! */
-                       if (!append(free, num_free, off))
-                               return TDB_OFF_ERR;
                        len = sizeof(p->u) + p->f.data_len;
                        if (off + len > zone_off + (1ULL << zhdr.zone_bits)) {
                                tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
@@ -427,6 +425,10 @@ static tdb_off_t check_zone(struct tdb_context *tdb, tdb_off_t zone_off,
                                         (long long)len, (long long)off);
                                return TDB_OFF_ERR;
                        }
+                       /* This record is free! */
+                       if (frec_magic(&p->f) == TDB_FREE_MAGIC
+                           && !append(free, num_free, off))
+                               return TDB_OFF_ERR;
                } else {
                        uint64_t klen, dlen, extra;