uint64_t hash_record(struct tdb_context *tdb, tdb_off_t off)
{
- struct tdb_used_record pad, *r;
+ const struct tdb_used_record *r;
const void *key;
uint64_t klen, hash;
- r = tdb_get(tdb, off, &pad, sizeof(pad));
+ r = tdb_access_read(tdb, off, sizeof(*r), true);
if (!r)
/* FIXME */
return 0;
klen = rec_key_length(r);
- key = tdb_access_read(tdb, off + sizeof(pad), klen, false);
+ tdb_access_release(tdb, r);
+
+ key = tdb_access_read(tdb, off + sizeof(*r), klen, false);
if (!key)
return 0;
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 (subhash == TDB_OFF_ERR)
return -1;
+ add_stat(tdb, alloc_subhash, 1);
if (zero_out(tdb, subhash + sizeof(struct tdb_used_record),
sizeof(tdb_off_t) << TDB_SUBLEVEL_HASH_BITS) == -1)
return -1;
return add_to_hash(tdb, h, new_off);
}
-/* No point holding references/copies of db once we drop lock. */
-static void release_entries(struct tdb_context *tdb,
- struct traverse_info *tinfo)
-{
- unsigned int i;
-
- for (i = 0; i < tinfo->num_levels; i++) {
- if (tinfo->levels[i].entries) {
- tdb_access_release(tdb, tinfo->levels[i].entries);
- tinfo->levels[i].entries = NULL;
- }
- }
-}
-
/* Traverse support: returns offset of record, or 0 or TDB_OFF_ERR. */
static tdb_off_t iterate_hash(struct tdb_context *tdb,
struct traverse_info *tinfo)
{
- tdb_off_t off;
+ tdb_off_t off, val;
unsigned int i;
struct traverse_level *tlevel;
tlevel = &tinfo->levels[tinfo->num_levels-1];
again:
- if (!tlevel->entries) {
- tlevel->entries = tdb_access_read(tdb, tlevel->hashtable,
- sizeof(tdb_off_t)
- * tlevel->total_buckets,
- true);
- if (!tlevel->entries)
+ for (i = tdb_find_nonzero_off(tdb, tlevel->hashtable,
+ tlevel->entry, tlevel->total_buckets);
+ i != tlevel->total_buckets;
+ i = tdb_find_nonzero_off(tdb, tlevel->hashtable,
+ i+1, tlevel->total_buckets)) {
+ val = tdb_read_off(tdb, tlevel->hashtable+sizeof(tdb_off_t)*i);
+ if (unlikely(val == TDB_OFF_ERR))
return TDB_OFF_ERR;
- }
- /* FIXME: Use tdb_find_nonzero_off? */
- for (i = tlevel->entry; i < tlevel->total_buckets; i++) {
- if (!tlevel->entries[i] || tlevel->entries[i] == tinfo->prev)
+ off = val & TDB_OFF_MASK;
+
+ /* This makes the delete-all-in-traverse case work
+ * (and simplifies our logic a little). */
+ if (off == tinfo->prev)
continue;
tlevel->entry = i;
- off = tlevel->entries[i] & TDB_OFF_MASK;
- if (!is_subhash(tlevel->entries[i])) {
+ if (!is_subhash(val)) {
/* Found one. */
- tinfo->prev = tlevel->entries[i];
- release_entries(tdb, tinfo);
+ tinfo->prev = off;
return off;
}
- /* When we come back, we want tne next one */
+ /* When we come back, we want the next one */
tlevel->entry++;
tinfo->num_levels++;
tlevel++;
tlevel->hashtable = off + sizeof(struct tdb_used_record);
tlevel->entry = 0;
- tlevel->entries = NULL;
tlevel->total_buckets = (1 << TDB_SUBLEVEL_HASH_BITS);
goto again;
}
/* Nothing there? */
- if (tinfo->num_levels == 1) {
- release_entries(tdb, tinfo);
+ if (tinfo->num_levels == 1)
return 0;
- }
/* Go back up and keep searching. */
- tdb_access_release(tdb, tlevel->entries);
tinfo->num_levels--;
tlevel--;
goto again;
/* 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;
tinfo->num_levels = 1;
tinfo->levels[0].hashtable = offsetof(struct tdb_header, hashtable);
- tinfo->levels[0].entries = NULL;
tinfo->levels[0].entry = 0;
tinfo->levels[0].total_buckets = (1 << TDB_HASH_GROUP_BITS);
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