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Diffstat (limited to 'lib/tdb2/tdb1_lock.c')
| -rw-r--r-- | lib/tdb2/tdb1_lock.c | 560 |
1 files changed, 0 insertions, 560 deletions
diff --git a/lib/tdb2/tdb1_lock.c b/lib/tdb2/tdb1_lock.c deleted file mode 100644 index 5cc0ad6567..0000000000 --- a/lib/tdb2/tdb1_lock.c +++ /dev/null @@ -1,560 +0,0 @@ - /* - Unix SMB/CIFS implementation. - - trivial database library - - Copyright (C) Andrew Tridgell 1999-2005 - Copyright (C) Paul `Rusty' Russell 2000 - Copyright (C) Jeremy Allison 2000-2003 - - ** NOTE! The following LGPL license applies to the tdb - ** library. This does NOT imply that all of Samba is released - ** under the LGPL - - This library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 3 of the License, or (at your option) any later version. - - This library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with this library; if not, see <http://www.gnu.org/licenses/>. -*/ - -#include "tdb1_private.h" - -/* list -1 is the alloc list, otherwise a hash chain. */ -static tdb1_off_t lock_offset(int list) -{ - return TDB1_FREELIST_TOP + 4*list; -} - -/* a byte range locking function - return 0 on success - this functions locks/unlocks 1 byte at the specified offset. - - On error, errno is also set so that errors are passed back properly - through tdb1_open(). - - note that a len of zero means lock to end of file -*/ -int tdb1_brlock(struct tdb_context *tdb, - int rw_type, tdb1_off_t offset, size_t len, - enum tdb_lock_flags flags) -{ - enum TDB_ERROR ecode = tdb_brlock(tdb, rw_type, offset, len, flags - | TDB_LOCK_NOCHECK); - if (ecode == TDB_SUCCESS) - return 0; - tdb->last_error = ecode; - return -1; -} - -int tdb1_brunlock(struct tdb_context *tdb, - int rw_type, tdb1_off_t offset, size_t len) -{ - enum TDB_ERROR ecode = tdb_brunlock(tdb, rw_type, offset, len); - if (ecode == TDB_SUCCESS) - return 0; - tdb->last_error = ecode; - return -1; -} - -int tdb1_allrecord_upgrade(struct tdb_context *tdb) -{ - enum TDB_ERROR ecode = tdb_allrecord_upgrade(tdb, TDB1_FREELIST_TOP); - if (ecode == TDB_SUCCESS) - return 0; - tdb->last_error = ecode; - return -1; -} - -static struct tdb_lock *tdb1_find_nestlock(struct tdb_context *tdb, - tdb1_off_t offset) -{ - unsigned int i; - - for (i=0; i<tdb->file->num_lockrecs; i++) { - if (tdb->file->lockrecs[i].off == offset) { - return &tdb->file->lockrecs[i]; - } - } - return NULL; -} - -/* lock an offset in the database. */ -int tdb1_nest_lock(struct tdb_context *tdb, uint32_t offset, int ltype, - enum tdb_lock_flags flags) -{ - enum TDB_ERROR ecode; - - if (offset >= lock_offset(tdb->tdb1.header.hash_size)) { - tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR, - "tdb1_lock: invalid offset %u for" - " ltype=%d", - offset, ltype); - return -1; - } - - ecode = tdb_nest_lock(tdb, offset, ltype, flags | TDB_LOCK_NOCHECK); - if (unlikely(ecode != TDB_SUCCESS)) { - tdb->last_error = ecode; - return -1; - } - return 0; -} - -static int tdb1_lock_and_recover(struct tdb_context *tdb) -{ - int ret; - - /* We need to match locking order in transaction commit. */ - if (tdb1_brlock(tdb, F_WRLCK, TDB1_FREELIST_TOP, 0, - TDB_LOCK_WAIT|TDB_LOCK_NOCHECK)) { - return -1; - } - - if (tdb1_brlock(tdb, F_WRLCK, TDB1_OPEN_LOCK, 1, - TDB_LOCK_WAIT|TDB_LOCK_NOCHECK)) { - tdb1_brunlock(tdb, F_WRLCK, TDB1_FREELIST_TOP, 0); - return -1; - } - - ret = tdb1_transaction_recover(tdb); - - tdb1_brunlock(tdb, F_WRLCK, TDB1_OPEN_LOCK, 1); - tdb1_brunlock(tdb, F_WRLCK, TDB1_FREELIST_TOP, 0); - - return ret; -} - -static bool have_data_locks(const struct tdb_context *tdb) -{ - unsigned int i; - - for (i = 0; i < tdb->file->num_lockrecs; i++) { - if (tdb->file->lockrecs[i].off >= lock_offset(-1)) - return true; - } - return false; -} - -static int tdb1_lock_list(struct tdb_context *tdb, int list, int ltype, - enum tdb_lock_flags waitflag) -{ - int ret; - bool check = false; - - /* a allrecord lock allows us to avoid per chain locks */ - if (tdb->file->allrecord_lock.count) { - if (!check_lock_pid(tdb, "tdb1_lock_list", true)) { - tdb->last_error = TDB_ERR_LOCK; - return -1; - } - if (tdb->file->allrecord_lock.owner != tdb) { - tdb->last_error = owner_conflict(tdb, "tdb1_lock_list"); - return -1; - } - if (ltype == tdb->file->allrecord_lock.ltype - || ltype == F_RDLCK) { - return 0; - } - tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK, - TDB_LOG_USE_ERROR, - "tdb1_lock_list:" - " already have read lock"); - return -1; - } - - /* Only check when we grab first data lock. */ - check = !have_data_locks(tdb); - ret = tdb1_nest_lock(tdb, lock_offset(list), ltype, waitflag); - - if (ret == 0 && check) { - tdb_bool_err berr = tdb1_needs_recovery(tdb); - - if (berr < 0) { - return -1; - } - if (berr == true) { - tdb1_nest_unlock(tdb, lock_offset(list), ltype); - - if (tdb1_lock_and_recover(tdb) == -1) { - return -1; - } - return tdb1_lock_list(tdb, list, ltype, waitflag); - } - } - return ret; -} - -/* lock a list in the database. list -1 is the alloc list */ -int tdb1_lock(struct tdb_context *tdb, int list, int ltype) -{ - int ret; - - ret = tdb1_lock_list(tdb, list, ltype, TDB_LOCK_WAIT); - /* Don't log for EAGAIN and EINTR: they could have overridden lock fns */ - if (ret && errno != EAGAIN && errno != EINTR) { - tdb_logerr(tdb, tdb->last_error, TDB_LOG_ERROR, - "tdb1_lock failed on list %d " - "ltype=%d (%s)", list, ltype, strerror(errno)); - } - return ret; -} - -int tdb1_nest_unlock(struct tdb_context *tdb, uint32_t offset, int ltype) -{ - enum TDB_ERROR ecode; - - /* Sanity checks */ - if (offset >= lock_offset(tdb->tdb1.header.hash_size)) { - tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR, - "tdb1_unlock: offset %u invalid (%d)", - offset, tdb->tdb1.header.hash_size); - return -1; - } - - ecode = tdb_nest_unlock(tdb, offset, ltype); - if (unlikely(ecode != TDB_SUCCESS)) { - tdb->last_error = ecode; - return -1; - } - return 0; -} - -int tdb1_unlock(struct tdb_context *tdb, int list, int ltype) -{ - /* a global lock allows us to avoid per chain locks */ - if (tdb->file->allrecord_lock.count && - (ltype == tdb->file->allrecord_lock.ltype || ltype == F_RDLCK)) { - if (tdb->file->allrecord_lock.owner != tdb) { - tdb->last_error = owner_conflict(tdb, "tdb1_unlock"); - return -1; - } - return 0; - } - - if (tdb->file->allrecord_lock.count) { - tdb->last_error = TDB_ERR_LOCK; - return -1; - } - - return tdb1_nest_unlock(tdb, lock_offset(list), ltype); -} - -/* - get the transaction lock - */ -int tdb1_transaction_lock(struct tdb_context *tdb, int ltype, - enum tdb_lock_flags lockflags) -{ - return tdb1_nest_lock(tdb, TDB1_TRANSACTION_LOCK, ltype, lockflags); -} - -/* - release the transaction lock - */ -int tdb1_transaction_unlock(struct tdb_context *tdb, int ltype) -{ - return tdb1_nest_unlock(tdb, TDB1_TRANSACTION_LOCK, ltype); -} - -/* lock/unlock entire database. It can only be upgradable if you have some - * other way of guaranteeing exclusivity (ie. transaction write lock). - * We do the locking gradually to avoid being starved by smaller locks. */ -int tdb1_allrecord_lock(struct tdb_context *tdb, int ltype, - enum tdb_lock_flags flags, bool upgradable) -{ - enum TDB_ERROR ecode; - tdb_bool_err berr; - - /* tdb_lock_gradual() doesn't know about tdb->tdb1.traverse_read. */ - if (tdb->tdb1.traverse_read && !(tdb->flags & TDB_NOLOCK)) { - tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK, - TDB_LOG_USE_ERROR, - "tdb1_allrecord_lock during" - " tdb1_read_traverse"); - return -1; - } - - if (tdb->file->allrecord_lock.count - && tdb->file->allrecord_lock.ltype == ltype) { - tdb->file->allrecord_lock.count++; - return 0; - } - - if (tdb1_have_extra_locks(tdb)) { - /* can't combine global and chain locks */ - tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK, - TDB_LOG_USE_ERROR, - "tdb1_allrecord_lock holding" - " other locks"); - return -1; - } - - if (upgradable && ltype != F_RDLCK) { - /* tdb error: you can't upgrade a write lock! */ - tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK, - TDB_LOG_ERROR, - "tdb1_allrecord_lock cannot" - " have upgradable write lock"); - return -1; - } - - /* We cover two kinds of locks: - * 1) Normal chain locks. Taken for almost all operations. - * 3) Individual records locks. Taken after normal or free - * chain locks. - * - * It is (1) which cause the starvation problem, so we're only - * gradual for that. */ - ecode = tdb_lock_gradual(tdb, ltype, flags | TDB_LOCK_NOCHECK, - TDB1_FREELIST_TOP, tdb->tdb1.header.hash_size * 4); - if (ecode != TDB_SUCCESS) { - tdb->last_error = ecode; - return -1; - } - - /* Grab individual record locks. */ - if (tdb1_brlock(tdb, ltype, lock_offset(tdb->tdb1.header.hash_size), 0, - flags) == -1) { - tdb1_brunlock(tdb, ltype, TDB1_FREELIST_TOP, - tdb->tdb1.header.hash_size * 4); - return -1; - } - - tdb->file->allrecord_lock.owner = tdb; - tdb->file->allrecord_lock.count = 1; - tdb->file->locker = getpid(); - /* If it's upgradable, it's actually exclusive so we can treat - * it as a write lock. */ - tdb->file->allrecord_lock.ltype = upgradable ? F_WRLCK : ltype; - tdb->file->allrecord_lock.off = upgradable; - - berr = tdb1_needs_recovery(tdb); - if (berr < 0) { - return -1; - } - - if (berr == true) { - tdb1_allrecord_unlock(tdb, ltype); - if (tdb1_lock_and_recover(tdb) == -1) { - return -1; - } - return tdb1_allrecord_lock(tdb, ltype, flags, upgradable); - } - - return 0; -} - - - -/* unlock entire db */ -int tdb1_allrecord_unlock(struct tdb_context *tdb, int ltype) -{ - /* Don't try this during r/o traversal! */ - if (tdb->tdb1.traverse_read) { - tdb->last_error = TDB_ERR_LOCK; - return -1; - } - - if (tdb->file->allrecord_lock.count == 0) { - tdb->last_error = TDB_ERR_LOCK; - return -1; - } - - /* Upgradable locks are marked as write locks. */ - if (tdb->file->allrecord_lock.ltype != ltype - && (!tdb->file->allrecord_lock.off || ltype != F_RDLCK)) { - tdb->last_error = TDB_ERR_LOCK; - return -1; - } - - if (tdb->file->allrecord_lock.count > 1) { - if (tdb->file->allrecord_lock.owner != tdb) { - tdb->last_error - = owner_conflict(tdb, "tdb1_allrecord_unlock"); - return -1; - } - tdb->file->allrecord_lock.count--; - return 0; - } - - tdb->file->allrecord_lock.count = 0; - tdb->file->allrecord_lock.ltype = 0; - - if (tdb1_brunlock(tdb, ltype, TDB1_FREELIST_TOP, 0)) { - tdb_logerr(tdb, tdb->last_error, TDB_LOG_ERROR, - "tdb1_unlockall failed (%s)", strerror(errno)); - return -1; - } - - return 0; -} - -/* lock/unlock one hash chain. This is meant to be used to reduce - contention - it cannot guarantee how many records will be locked */ -int tdb1_chainlock(struct tdb_context *tdb, TDB_DATA key) -{ - int ret = tdb1_lock(tdb, - TDB1_BUCKET(tdb_hash(tdb, key.dptr, key.dsize)), - F_WRLCK); - return ret; -} - -int tdb1_chainunlock(struct tdb_context *tdb, TDB_DATA key) -{ - return tdb1_unlock(tdb, TDB1_BUCKET(tdb_hash(tdb, key.dptr, key.dsize)), - F_WRLCK); -} - -int tdb1_chainlock_read(struct tdb_context *tdb, TDB_DATA key) -{ - int ret; - ret = tdb1_lock(tdb, TDB1_BUCKET(tdb_hash(tdb, key.dptr, key.dsize)), - F_RDLCK); - return ret; -} - -int tdb1_chainunlock_read(struct tdb_context *tdb, TDB_DATA key) -{ - return tdb1_unlock(tdb, TDB1_BUCKET(tdb_hash(tdb, key.dptr, key.dsize)), - F_RDLCK); -} - -/* record lock stops delete underneath */ -int tdb1_lock_record(struct tdb_context *tdb, tdb1_off_t off) -{ - if (tdb->file->allrecord_lock.count) { - if (!check_lock_pid(tdb, "tdb1_lock_record", true)) { - tdb->last_error = TDB_ERR_LOCK; - return -1; - } - if (tdb->file->allrecord_lock.owner != tdb) { - tdb->last_error = owner_conflict(tdb, - "tdb1_lock_record"); - return -1; - } - return 0; - } - return off ? tdb1_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 tdb1_write_lock_record(struct tdb_context *tdb, tdb1_off_t off) -{ - struct tdb1_traverse_lock *i; - for (i = &tdb->tdb1.travlocks; i; i = i->next) - if (i->off == off) - return -1; - if (tdb->file->allrecord_lock.count) { - if (!check_lock_pid(tdb, "tdb1_write_lock_record", true)) { - tdb->last_error = TDB_ERR_LOCK; - return -1; - } - if (tdb->file->allrecord_lock.owner != tdb) { - tdb->last_error - = owner_conflict(tdb, "tdb1_write_lock_record"); - return -1; - } - if (tdb->file->allrecord_lock.ltype == F_WRLCK) { - return 0; - } - return -1; - } - return tdb1_brlock(tdb, F_WRLCK, off, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE); -} - -int tdb1_write_unlock_record(struct tdb_context *tdb, tdb1_off_t off) -{ - if (tdb->file->allrecord_lock.count) { - if (tdb->file->allrecord_lock.owner != tdb) { - tdb->last_error - = owner_conflict(tdb, - "tdb1_write_unlock_record"); - return -1; - } - return 0; - } - return tdb1_brunlock(tdb, F_WRLCK, off, 1); -} - -/* fcntl locks don't stack: avoid unlocking someone else's */ -int tdb1_unlock_record(struct tdb_context *tdb, tdb1_off_t off) -{ - struct tdb1_traverse_lock *i; - uint32_t count = 0; - - if (tdb->file->allrecord_lock.count) { - if (tdb->file->allrecord_lock.owner != tdb) { - tdb->last_error = owner_conflict(tdb, - "tdb1_unlock_record"); - return -1; - } - return 0; - } - - if (off == 0) - return 0; - for (i = &tdb->tdb1.travlocks; i; i = i->next) - if (i->off == off) - count++; - return (count == 1 ? tdb1_brunlock(tdb, F_RDLCK, off, 1) : 0); -} - -bool tdb1_have_extra_locks(struct tdb_context *tdb) -{ - unsigned int extra = tdb->file->num_lockrecs; - - /* A transaction holds the lock for all records. */ - if (!tdb->tdb1.transaction && tdb->file->allrecord_lock.count) { - return true; - } - - /* We always hold the active lock if CLEAR_IF_FIRST. */ - if (tdb1_find_nestlock(tdb, TDB1_ACTIVE_LOCK)) { - extra--; - } - - /* In a transaction, we expect to hold the transaction lock */ - if (tdb->tdb1.transaction - && tdb1_find_nestlock(tdb, TDB1_TRANSACTION_LOCK)) { - extra--; - } - - return extra; -} - -/* The transaction code uses this to remove all locks. */ -void tdb1_release_transaction_locks(struct tdb_context *tdb) -{ - unsigned int i, active = 0; - - if (tdb->file->allrecord_lock.count != 0) { - tdb1_brunlock(tdb, tdb->file->allrecord_lock.ltype, TDB1_FREELIST_TOP, 0); - tdb->file->allrecord_lock.count = 0; - } - - for (i=0;i<tdb->file->num_lockrecs;i++) { - struct tdb_lock *lck = &tdb->file->lockrecs[i]; - - /* Don't release the active lock! Copy it to first entry. */ - if (lck->off == TDB1_ACTIVE_LOCK) { - tdb->file->lockrecs[active++] = *lck; - } else { - tdb1_brunlock(tdb, lck->ltype, lck->off, 1); - } - } - tdb->file->num_lockrecs = active; - if (tdb->file->num_lockrecs == 0) { - SAFE_FREE(tdb->file->lockrecs); - } -} |