*/
#include "private.h"
+#include <assert.h>
+#include <ccan/build_assert/build_assert.h>
static int fcntl_lock(struct tdb_context *tdb,
int rw, off_t off, off_t len, bool waitflag)
{
struct tdb_lock_type *new_lck;
- if (offset >= TDB_HASH_LOCK_START + (1ULL << tdb->header.v.hash_bits)
- + (tdb->header.v.num_zones * (tdb->header.v.free_buckets+1))) {
+ if (offset >= TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE + tdb->map_size / 8) {
tdb->ecode = TDB_ERR_LOCK;
tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
- "tdb_lock: invalid offset %llu for ltype=%d\n",
+ "tdb_lock: invalid offset %llu ltype=%d\n",
(long long)offset, ltype);
return -1;
}
+
if (tdb->flags & TDB_NOLOCK)
return 0;
*/
*lck = tdb->lockrecs[--tdb->num_lockrecs];
- if (tdb->num_lockrecs == 0) {
- /* If we're not holding any locks, header can change. */
- tdb->header_uptodate = false;
- }
-
return ret;
}
int ret;
enum tdb_lock_flags nb_flags = (flags & ~TDB_LOCK_WAIT);
- if (len <= 4) {
- /* Single record. Just do blocking lock. */
+ if (len <= 1) {
+ /* 0 would mean to end-of-file... */
+ assert(len != 0);
+ /* Single hash. Just do blocking lock. */
return tdb_brlock(tdb, ltype, off, len, flags);
}
/* lock/unlock entire database. It can only be upgradable if you have some
* other way of guaranteeing exclusivity (ie. transaction write lock).
- * Note that we don't lock the free chains: noone can get those locks
- * without a hash chain lock first.
- * The header *will be* up to date once this returns success. */
+ * Note that we don't lock the free chains: currently noone can get those locks
+ * without a hash chain lock first. */
int tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
enum tdb_lock_flags flags, bool upgradable)
{
- tdb_off_t hash_size;
-
/* FIXME: There are no locks on read-only dbs */
if (tdb->read_only) {
tdb->ecode = TDB_ERR_LOCK;
return -1;
}
- /* Lock all the hash buckets. */
again:
- hash_size = (1ULL << tdb->header.v.hash_bits);
if (tdb_lock_gradual(tdb, ltype, flags, TDB_HASH_LOCK_START,
- hash_size)) {
+ TDB_HASH_LOCK_RANGE)) {
if (!(flags & TDB_LOCK_PROBE)) {
tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
"tdb_lockall hashes failed (%s)\n",
tdb->allrecord_lock.ltype = upgradable ? F_WRLCK : ltype;
tdb->allrecord_lock.off = upgradable;
- /* Now we re-check header, holding lock. */
- if (unlikely(header_changed(tdb))) {
- tdb_allrecord_unlock(tdb, ltype);
- goto again;
- }
-
/* Now check for needing recovery. */
if (unlikely(tdb_needs_recovery(tdb))) {
tdb_allrecord_unlock(tdb, ltype);
tdb_nest_unlock(tdb, TDB_OPEN_LOCK, F_WRLCK);
}
+int tdb_lock_expand(struct tdb_context *tdb, int ltype)
+{
+ return tdb_nest_lock(tdb, TDB_EXPANSION_LOCK, ltype, TDB_LOCK_WAIT);
+}
+
+void tdb_unlock_expand(struct tdb_context *tdb, int ltype)
+{
+ tdb_nest_unlock(tdb, TDB_EXPANSION_LOCK, ltype);
+}
+
/* unlock entire db */
int tdb_allrecord_unlock(struct tdb_context *tdb, int ltype)
{
- tdb_off_t hash_size;
-
/* FIXME: There are no locks on read-only dbs */
if (tdb->read_only) {
tdb->ecode = TDB_ERR_LOCK;
tdb->allrecord_lock.count = 0;
tdb->allrecord_lock.ltype = 0;
- tdb->header_uptodate = false;
- hash_size = (1ULL << tdb->header.v.hash_bits);
+ return tdb_brunlock(tdb, ltype, TDB_HASH_LOCK_START,
+ TDB_HASH_LOCK_RANGE);
+}
- return tdb_brunlock(tdb, ltype, TDB_HASH_LOCK_START, hash_size);
+bool tdb_has_expansion_lock(struct tdb_context *tdb)
+{
+ return find_nestlock(tdb, TDB_EXPANSION_LOCK) != NULL
+ || (tdb->flags & TDB_NOLOCK);
}
bool tdb_has_locks(struct tdb_context *tdb)
}
#endif
-/* Returns the list we actually locked. */
-tdb_off_t tdb_lock_list(struct tdb_context *tdb, uint64_t hash,
- int ltype, enum tdb_lock_flags waitflag)
+int tdb_lock_hashes(struct tdb_context *tdb,
+ tdb_off_t hash_lock,
+ tdb_len_t hash_range,
+ int ltype, enum tdb_lock_flags waitflag)
{
- tdb_off_t list = hash & ((1ULL << tdb->header.v.hash_bits) - 1);
- /* Header can change ONLY if we had no locks before. */
- bool can_change = tdb->num_lockrecs == 0;
+ /* FIXME: Do this properly, using hlock_range */
+ unsigned lock = TDB_HASH_LOCK_START
+ + (hash_lock >> (64 - TDB_HASH_LOCK_RANGE_BITS));
/* a allrecord lock allows us to avoid per chain locks */
if (tdb->allrecord_lock.count &&
(ltype == tdb->allrecord_lock.ltype || ltype == F_RDLCK)) {
- return list;
+ return 0;
}
if (tdb->allrecord_lock.count) {
"tdb_lock_list: have %s allrecordlock\n",
tdb->allrecord_lock.ltype == F_RDLCK
? "read" : "write");
- return TDB_OFF_ERR;
+ return -1;
}
-again:
- if (tdb_nest_lock(tdb, TDB_HASH_LOCK_START + list, ltype, waitflag))
- return TDB_OFF_ERR;
-
- if (can_change && unlikely(header_changed(tdb))) {
- tdb_off_t new = hash & ((1ULL << tdb->header.v.hash_bits) - 1);
- if (new != list) {
- tdb_nest_unlock(tdb, TDB_HASH_LOCK_START+list, ltype);
- list = new;
- goto again;
- }
- }
- return list;
+ return tdb_nest_lock(tdb, lock, ltype, waitflag);
}
-int tdb_unlock_list(struct tdb_context *tdb, tdb_off_t list, int ltype)
+int tdb_unlock_hashes(struct tdb_context *tdb,
+ tdb_off_t hash_lock,
+ tdb_len_t hash_range, int ltype)
{
- list &= ((1ULL << tdb->header.v.hash_bits) - 1);
+ unsigned lock = TDB_HASH_LOCK_START
+ + (hash_lock >> (64 - TDB_HASH_LOCK_RANGE_BITS));
/* a allrecord lock allows us to avoid per chain locks */
if (tdb->allrecord_lock.count) {
return -1;
}
return 0;
- } else {
- return tdb_nest_unlock(tdb, TDB_HASH_LOCK_START + list, ltype);
}
+
+ return tdb_nest_unlock(tdb, lock, ltype);
}
-/* Free list locks come after hash locks */
-int tdb_lock_free_list(struct tdb_context *tdb, tdb_off_t flist,
- enum tdb_lock_flags waitflag)
+/* Hash locks use TDB_HASH_LOCK_START + the next 30 bits.
+ * Then we begin; bucket offsets are sizeof(tdb_len_t) apart, so we divide.
+ * The result is that on 32 bit systems we don't use lock values > 2^31 on
+ * files that are less than 4GB.
+ */
+static tdb_off_t free_lock_off(tdb_off_t b_off)
{
+ return TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE + b_off / sizeof(tdb_off_t);
+}
+
+int tdb_lock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off,
+ enum tdb_lock_flags waitflag)
+{
+ assert(b_off >= sizeof(struct tdb_header));
+
/* You're supposed to have a hash lock first! */
if (!(tdb->flags & TDB_NOLOCK) && !tdb_has_locks(tdb)) {
tdb->ecode = TDB_ERR_LOCK;
return -1;
}
- return tdb_nest_lock(tdb, TDB_HASH_LOCK_START
- + (1ULL << tdb->header.v.hash_bits)
- + flist, F_WRLCK, waitflag);
+ return tdb_nest_lock(tdb, free_lock_off(b_off), F_WRLCK, waitflag);
}
-void tdb_unlock_free_list(struct tdb_context *tdb, tdb_off_t flist)
+void tdb_unlock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off)
{
if (tdb->allrecord_lock.count)
return;
- tdb_nest_unlock(tdb, TDB_HASH_LOCK_START
- + (1ULL << tdb->header.v.hash_bits)
- + flist, F_WRLCK);
+ tdb_nest_unlock(tdb, free_lock_off(b_off), F_WRLCK);
}
/* Even if the entry isn't in this hash bucket, you'd have to lock this
int ret;
uint64_t h = tdb_hash(tdb, key->dptr, key->dsize);
- ret = tdb_lock_list(tdb, h, ltype, waitflag) == TDB_OFF_ERR ? -1 : 0;
+ ret = tdb_lock_hashes(tdb, h, 1, ltype, waitflag);
tdb_trace_1rec(tdb, func, *key);
return ret;
}
{
uint64_t h = tdb_hash(tdb, key.dptr, key.dsize);
tdb_trace_1rec(tdb, "tdb_chainunlock", key);
- return tdb_unlock_list(tdb, h, F_WRLCK);
+ return tdb_unlock_hashes(tdb, h, 1, F_WRLCK);
}
#if 0
projects / ccan / blobdiff