return ret;
}
-#if 0
/*
upgrade a read lock to a write lock. This needs to be handled in a
special way as some OSes (such as solaris) have too conservative
while (count--) {
struct timeval tv;
if (tdb_brlock(tdb, F_WRLCK,
- TDB_HASH_LOCK_START
- + (1ULL << tdb->header.v.hash_bits), 0,
+ TDB_HASH_LOCK_START, 0,
TDB_LOCK_WAIT|TDB_LOCK_PROBE) == 0) {
tdb->allrecord_lock.ltype = F_WRLCK;
tdb->allrecord_lock.off = 0;
"tdb_allrecord_upgrade failed\n");
return -1;
}
-#endif
static struct tdb_lock_type *find_nestlock(struct tdb_context *tdb,
tdb_off_t offset)
return NULL;
}
+int tdb_lock_and_recover(struct tdb_context *tdb)
+{
+ int ret;
+
+ if (tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK,
+ false) == -1) {
+ return -1;
+ }
+
+ if (tdb_lock_open(tdb, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK) == -1) {
+ tdb_allrecord_unlock(tdb, F_WRLCK);
+ return -1;
+ }
+ ret = tdb_transaction_recover(tdb);
+
+ tdb_unlock_open(tdb);
+ tdb_allrecord_unlock(tdb, F_WRLCK);
+
+ return ret;
+}
+
/* lock an offset in the database. */
static int tdb_nest_lock(struct tdb_context *tdb, tdb_off_t offset, int ltype,
enum tdb_lock_flags flags)
new_lck = find_nestlock(tdb, offset);
if (new_lck) {
- /*
- * Just increment the in-memory struct, posix locks
- * don't stack.
- */
+ if (new_lck->ltype == F_RDLCK && ltype == F_WRLCK) {
+ tdb->ecode = TDB_ERR_LOCK;
+ tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
+ "tdb_nest_lock: offset %llu has read lock\n",
+ (long long)offset);
+ return -1;
+ }
+ /* Just increment the struct, posix locks don't stack. */
new_lck->count++;
return 0;
}
return -1;
}
+ /* First time we grab a lock, perhaps someone died in commit? */
+ if (!(flags & TDB_LOCK_NOCHECK)
+ && tdb->num_lockrecs == 0
+ && unlikely(tdb_needs_recovery(tdb))) {
+ tdb_brunlock(tdb, ltype, offset, 1);
+
+ if (tdb_lock_and_recover(tdb) == -1) {
+ return -1;
+ }
+
+ if (tdb_brlock(tdb, ltype, offset, 1, flags)) {
+ return -1;
+ }
+ }
+
tdb->lockrecs[tdb->num_lockrecs].off = offset;
tdb->lockrecs[tdb->num_lockrecs].count = 1;
tdb->lockrecs[tdb->num_lockrecs].ltype = ltype;
return 0;
}
-static int tdb_lock_and_recover(struct tdb_context *tdb)
-{
-#if 0 /* FIXME */
-
- int ret;
-
- /* We need to match locking order in transaction commit. */
- if (tdb_brlock(tdb, F_WRLCK, FREELIST_TOP, 0, TDB_LOCK_WAIT)) {
- return -1;
- }
-
- if (tdb_brlock(tdb, F_WRLCK, OPEN_LOCK, 1, TDB_LOCK_WAIT)) {
- tdb_brunlock(tdb, F_WRLCK, FREELIST_TOP, 0);
- return -1;
- }
-
- ret = tdb_transaction_recover(tdb);
-
- tdb_brunlock(tdb, F_WRLCK, OPEN_LOCK, 1);
- tdb_brunlock(tdb, F_WRLCK, FREELIST_TOP, 0);
-
- return ret;
-#else
- abort();
- return -1;
-#endif
-}
-
-static bool tdb_needs_recovery(struct tdb_context *tdb)
-{
- /* FIXME */
- return false;
-}
-
static int tdb_nest_unlock(struct tdb_context *tdb, tdb_off_t off, int ltype)
{
int ret = -1;
return ret;
}
-#if 0
/*
get the transaction lock
*/
-int tdb_transaction_lock(struct tdb_context *tdb, int ltype,
- enum tdb_lock_flags lockflags)
+int tdb_transaction_lock(struct tdb_context *tdb, int ltype)
{
- return tdb_nest_lock(tdb, TRANSACTION_LOCK, ltype, lockflags);
+ return tdb_nest_lock(tdb, TDB_TRANSACTION_LOCK, ltype, TDB_LOCK_WAIT);
}
/*
*/
int tdb_transaction_unlock(struct tdb_context *tdb, int ltype)
{
- return tdb_nest_unlock(tdb, TRANSACTION_LOCK, ltype, false);
+ return tdb_nest_unlock(tdb, TDB_TRANSACTION_LOCK, ltype);
}
-#endif
/* We only need to lock individual bytes, but Linux merges consecutive locks
* so we lock in contiguous ranges. */
return -1;
}
- if (tdb->allrecord_lock.count && tdb->allrecord_lock.ltype == ltype) {
+ if (tdb->allrecord_lock.count
+ && (ltype == F_RDLCK || tdb->allrecord_lock.ltype == F_WRLCK)) {
tdb->allrecord_lock.count++;
return 0;
}
return -1;
}
- if (tdb_has_locks(tdb)) {
+ if (tdb_has_hash_locks(tdb)) {
/* can't combine global and chain locks */
tdb->ecode = TDB_ERR_LOCK;
tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
tdb->allrecord_lock.off = upgradable;
/* Now check for needing recovery. */
- if (unlikely(tdb_needs_recovery(tdb))) {
+ if (!(flags & TDB_LOCK_NOCHECK) && unlikely(tdb_needs_recovery(tdb))) {
tdb_allrecord_unlock(tdb, ltype);
if (tdb_lock_and_recover(tdb) == -1) {
return -1;
return 0;
}
-int tdb_lock_open(struct tdb_context *tdb)
+int tdb_lock_open(struct tdb_context *tdb, enum tdb_lock_flags flags)
{
- return tdb_nest_lock(tdb, TDB_OPEN_LOCK, F_WRLCK, TDB_LOCK_WAIT);
+ return tdb_nest_lock(tdb, TDB_OPEN_LOCK, F_WRLCK, flags);
}
void tdb_unlock_open(struct tdb_context *tdb)
tdb_nest_unlock(tdb, TDB_OPEN_LOCK, F_WRLCK);
}
+bool tdb_has_open_lock(struct tdb_context *tdb)
+{
+ return find_nestlock(tdb, TDB_OPEN_LOCK) != NULL;
+}
+
int tdb_lock_expand(struct tdb_context *tdb, int ltype)
{
- return tdb_nest_lock(tdb, TDB_EXPANSION_LOCK, ltype, TDB_LOCK_WAIT);
+ /* Lock doesn't protect data, so don't check (we recurse if we do!) */
+ return tdb_nest_lock(tdb, TDB_EXPANSION_LOCK, ltype,
+ TDB_LOCK_WAIT | TDB_LOCK_NOCHECK);
}
void tdb_unlock_expand(struct tdb_context *tdb, int ltype)
return find_nestlock(tdb, TDB_EXPANSION_LOCK) != NULL;
}
-bool tdb_has_locks(struct tdb_context *tdb)
-{
- return tdb->allrecord_lock.count || tdb->num_lockrecs;
-}
-
-#if 0
-/* lock entire database with write lock */
-int tdb_lockall(struct tdb_context *tdb)
-{
- tdb_trace(tdb, "tdb_lockall");
- return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
-}
-
-/* lock entire database with write lock - nonblocking varient */
-int tdb_lockall_nonblock(struct tdb_context *tdb)
-{
- int ret = tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_NOWAIT, false);
- tdb_trace_ret(tdb, "tdb_lockall_nonblock", ret);
- return ret;
-}
-
-/* unlock entire database with write lock */
-int tdb_unlockall(struct tdb_context *tdb)
-{
- tdb_trace(tdb, "tdb_unlockall");
- return tdb_allrecord_unlock(tdb, F_WRLCK);
-}
-
-/* lock entire database with read lock */
-int tdb_lockall_read(struct tdb_context *tdb)
+bool tdb_has_hash_locks(struct tdb_context *tdb)
{
- tdb_trace(tdb, "tdb_lockall_read");
- return tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false);
-}
-
-/* lock entire database with read lock - nonblock varient */
-int tdb_lockall_read_nonblock(struct tdb_context *tdb)
-{
- int ret = tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_NOWAIT, false);
- tdb_trace_ret(tdb, "tdb_lockall_read_nonblock", ret);
- return ret;
-}
+ unsigned int i;
-/* unlock entire database with read lock */
-int tdb_unlockall_read(struct tdb_context *tdb)
-{
- tdb_trace(tdb, "tdb_unlockall_read");
- return tdb_allrecord_unlock(tdb, F_RDLCK);
+ for (i=0; i<tdb->num_lockrecs; i++) {
+ if (tdb->lockrecs[i].off >= TDB_HASH_LOCK_START
+ && tdb->lockrecs[i].off < (TDB_HASH_LOCK_START
+ + TDB_HASH_LOCK_RANGE))
+ return true;
+ }
+ return false;
}
-#endif
static bool tdb_has_free_lock(struct tdb_context *tdb)
{
tdb_nest_unlock(tdb, free_lock_off(b_off), F_WRLCK);
}
-#if 0
-/* lock/unlock one hash chain, non-blocking. This is meant to be used
- to reduce contention - it cannot guarantee how many records will be
- locked */
-int tdb_chainlock_nonblock(struct tdb_context *tdb, TDB_DATA key)
-{
- return chainlock(tdb, &key, F_WRLCK, TDB_LOCK_NOWAIT,
- "tdb_chainlock_nonblock");
-}
-
-int tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key)
-{
- return chainlock(tdb, &key, F_RDLCK, TDB_LOCK_WAIT,
- "tdb_chainlock_read");
-}
-
-int tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key)
-{
- uint64_t h = tdb_hash(tdb, key.dptr, key.dsize);
- tdb_trace_1rec(tdb, "tdb_chainunlock_read", key);
- return tdb_unlock_list(tdb, h & ((1ULL << tdb->header.v.hash_bits)-1),
- F_RDLCK);
-}
-
-/* record lock stops delete underneath */
-int tdb_lock_record(struct tdb_context *tdb, tdb_off_t off)
-{
- if (tdb->allrecord_lock.count) {
- return 0;
- }
- return off ? tdb_brlock(tdb, F_RDLCK, off, 1, TDB_LOCK_WAIT) : 0;
-}
-
-/*
- Write locks override our own fcntl readlocks, so check it here.
- Note this is meant to be F_SETLK, *not* F_SETLKW, as it's not
- an error to fail to get the lock here.
-*/
-int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off)
-{
- struct tdb_traverse_lock *i;
- for (i = &tdb->travlocks; i; i = i->next)
- if (i->off == off)
- return -1;
- if (tdb->allrecord_lock.count) {
- if (tdb->allrecord_lock.ltype == F_WRLCK) {
- return 0;
- }
- return -1;
- }
- return tdb_brlock(tdb, F_WRLCK, off, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
-}
-
-int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off)
-{
- if (tdb->allrecord_lock.count) {
- return 0;
- }
- return tdb_brunlock(tdb, F_WRLCK, off, 1);
-}
-
-/* fcntl locks don't stack: avoid unlocking someone else's */
-int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off)
-{
- struct tdb_traverse_lock *i;
- uint32_t count = 0;
-
- if (tdb->allrecord_lock.count) {
- return 0;
- }
-
- if (off == 0)
- return 0;
- for (i = &tdb->travlocks; i; i = i->next)
- if (i->off == off)
- count++;
- return (count == 1 ? tdb_brunlock(tdb, F_RDLCK, off, 1) : 0);
-}
-
-/* The transaction code uses this to remove all locks. */
-void tdb_release_transaction_locks(struct tdb_context *tdb)
-{
- unsigned int i;
-
- if (tdb->allrecord_lock.count != 0) {
- tdb_off_t hash_size, free_size;
-
- hash_size = (1ULL << tdb->header.v.hash_bits)
- * sizeof(tdb_off_t);
- free_size = tdb->header.v.free_zones
- * (tdb->header.v.free_buckets + 1) * sizeof(tdb_off_t);
-
- tdb_brunlock(tdb, tdb->allrecord_lock.ltype,
- tdb->header.v.hash_off, hash_size);
- tdb_brunlock(tdb, tdb->allrecord_lock.ltype,
- tdb->header.v.free_off, free_size);
- tdb->allrecord_lock.count = 0;
- tdb->allrecord_lock.ltype = 0;
- }
-
- for (i = 0; i<tdb->num_lockrecs; i++) {
- struct tdb_lock_type *lck = &tdb->lockrecs[i];
-
- tdb_brunlock(tdb, lck->ltype, lck->off, 1);
- }
- tdb->num_lockrecs = 0;
- SAFE_FREE(tdb->lockrecs);
- tdb->header_uptodate = false;
-}
-#endif
-
void tdb_lock_init(struct tdb_context *tdb)
{
tdb->num_lockrecs = 0;
projects / ccan / blobdiff