return val >> (64-TDB_OFF_UPPER_STEAL) == (1<<TDB_OFF_UPPER_STEAL) - 1;
}
+/* FIXME: Guess the depth, don't over-lock! */
+static tdb_off_t hlock_range(tdb_off_t group, tdb_off_t *size)
+{
+ *size = 1ULL << (64 - (TDB_TOPLEVEL_HASH_BITS - TDB_HASH_GROUP_BITS));
+ return group << (64 - (TDB_TOPLEVEL_HASH_BITS - TDB_HASH_GROUP_BITS));
+}
+
/* This is the core routine which searches the hashtable for an entry.
* On error, no locks are held and TDB_OFF_ERR is returned.
- * Otherwise, hinfo is filled in.
+ * Otherwise, hinfo is filled in (and the optional tinfo).
* If not found, the return value is 0.
* If found, the return value is the offset, and *rec is the record. */
tdb_off_t find_and_lock(struct tdb_context *tdb,
struct tdb_data key,
int ltype,
struct hash_info *h,
- struct tdb_used_record *rec)
+ struct tdb_used_record *rec,
+ struct traverse_info *tinfo)
{
uint32_t i, group;
tdb_off_t hashtable;
group = use_bits(h, TDB_TOPLEVEL_HASH_BITS - TDB_HASH_GROUP_BITS);
h->home_bucket = use_bits(h, TDB_HASH_GROUP_BITS);
- /* FIXME: Guess the depth, don't over-lock! */
- h->hlock_start = (tdb_off_t)group
- << (64 - (TDB_TOPLEVEL_HASH_BITS - TDB_HASH_GROUP_BITS));
- h->hlock_range = 1ULL << (64 - (TDB_TOPLEVEL_HASH_BITS
- - TDB_HASH_GROUP_BITS));
+ h->hlock_start = hlock_range(group, &h->hlock_range);
if (tdb_lock_hashes(tdb, h->hlock_start, h->hlock_range, ltype,
TDB_LOCK_WAIT))
return TDB_OFF_ERR;
hashtable = offsetof(struct tdb_header, hashtable);
+ if (tinfo) {
+ tinfo->toplevel_group = group;
+ tinfo->num_levels = 1;
+ tinfo->levels[0].entry = 0;
+ tinfo->levels[0].hashtable = hashtable
+ + (group << TDB_HASH_GROUP_BITS) * sizeof(tdb_off_t);
+ tinfo->levels[0].total_buckets = 1 << TDB_HASH_GROUP_BITS;
+ }
while (likely(h->hash_used < 64)) {
/* Read in the hash group. */
if (is_subhash(h->group[h->home_bucket])) {
hashtable = (h->group[h->home_bucket] & TDB_OFF_MASK)
+ sizeof(struct tdb_used_record);
+ if (tinfo) {
+ /* When we come back, use *next* bucket */
+ tinfo->levels[tinfo->num_levels-1].entry
+ += h->home_bucket + 1;
+ }
group = use_bits(h, TDB_SUBLEVEL_HASH_BITS
- TDB_HASH_GROUP_BITS);
h->home_bucket = use_bits(h, TDB_HASH_GROUP_BITS);
+ if (tinfo) {
+ tinfo->levels[tinfo->num_levels].hashtable
+ = hashtable;
+ tinfo->levels[tinfo->num_levels].total_buckets
+ = 1 << TDB_SUBLEVEL_HASH_BITS;
+ tinfo->levels[tinfo->num_levels].entry
+ = group << TDB_HASH_GROUP_BITS;
+ tinfo->num_levels++;
+ }
continue;
}
if (!h->group[h->found_bucket])
break;
- if (match(tdb, h, &key, h->group[h->found_bucket], rec))
+ if (match(tdb, h, &key, h->group[h->found_bucket],
+ rec)) {
+ if (tinfo) {
+ tinfo->levels[tinfo->num_levels-1].entry
+ += h->found_bucket;
+ }
return h->group[h->found_bucket] & TDB_OFF_MASK;
+ }
}
/* Didn't find it: h indicates where it would go. */
return 0;
if (unlikely(val == TDB_OFF_ERR))
return TDB_OFF_ERR;
+ off = val & TDB_OFF_MASK;
+
/* This makes the delete-all-in-traverse case work
* (and simplifies our logic a little). */
- if (val == tinfo->prev)
+ if (off == tinfo->prev)
continue;
tlevel->entry = i;
- off = val & TDB_OFF_MASK;
if (!is_subhash(val)) {
/* Found one. */
- tinfo->prev = val;
+ tinfo->prev = off;
return off;
}
/* Return 1 if we find something, 0 if not, -1 on error. */
int next_in_hash(struct tdb_context *tdb, int ltype,
struct traverse_info *tinfo,
- TDB_DATA *kbuf, unsigned int *dlen)
+ TDB_DATA *kbuf, size_t *dlen)
{
const unsigned group_bits = TDB_TOPLEVEL_HASH_BITS-TDB_HASH_GROUP_BITS;
tdb_off_t hlock_start, hlock_range, off;
ltype);
return -1;
}
+ if (rec_magic(&rec) != TDB_MAGIC) {
+ tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
+ "next_in_hash:"
+ " corrupt record at %llu\n",
+ (long long)off);
+ return -1;
+ }
+
kbuf->dsize = rec_key_length(&rec);
/* They want data as well? */
/* Return 1 if we find something, 0 if not, -1 on error. */
int first_in_hash(struct tdb_context *tdb, int ltype,
struct traverse_info *tinfo,
- TDB_DATA *kbuf, unsigned int *dlen)
+ TDB_DATA *kbuf, size_t *dlen)
{
tinfo->prev = 0;
tinfo->toplevel_group = 0;
return next_in_hash(tdb, ltype, tinfo, kbuf, dlen);
}
+
+/* Even if the entry isn't in this hash bucket, you'd have to lock this
+ * bucket to find it. */
+static int chainlock(struct tdb_context *tdb, const TDB_DATA *key,
+ int ltype, enum tdb_lock_flags waitflag,
+ const char *func)
+{
+ int ret;
+ uint64_t h = tdb_hash(tdb, key->dptr, key->dsize);
+ tdb_off_t lockstart, locksize;
+ unsigned int group, gbits;
+
+ gbits = TDB_TOPLEVEL_HASH_BITS - TDB_HASH_GROUP_BITS;
+ group = bits(h, 64 - gbits, gbits);
+
+ lockstart = hlock_range(group, &locksize);
+
+ ret = tdb_lock_hashes(tdb, lockstart, locksize, ltype, waitflag);
+ tdb_trace_1rec(tdb, func, *key);
+ return ret;
+}
+
+/* lock/unlock one hash chain. This is meant to be used to reduce
+ contention - it cannot guarantee how many records will be locked */
+int tdb_chainlock(struct tdb_context *tdb, TDB_DATA key)
+{
+ return chainlock(tdb, &key, F_WRLCK, TDB_LOCK_WAIT, "tdb_chainlock");
+}
+
+int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key)
+{
+ uint64_t h = tdb_hash(tdb, key.dptr, key.dsize);
+ tdb_off_t lockstart, locksize;
+ unsigned int group, gbits;
+
+ gbits = TDB_TOPLEVEL_HASH_BITS - TDB_HASH_GROUP_BITS;
+ group = bits(h, 64 - gbits, gbits);
+
+ lockstart = hlock_range(group, &locksize);
+
+ tdb_trace_1rec(tdb, "tdb_chainunlock", key);
+ return tdb_unlock_hashes(tdb, lockstart, locksize, F_WRLCK);
+}
projects / ccan / blobdiff