- /*
+ /*
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
#include "tdb_private.h"
-void tdb_setalarm_sigptr(struct tdb_context *tdb, volatile sig_atomic_t *ptr)
+_PUBLIC_ void tdb_setalarm_sigptr(struct tdb_context *tdb, volatile sig_atomic_t *ptr)
{
tdb->interrupt_sig_ptr = ptr;
}
int rw, off_t off, off_t len, bool waitflag)
{
struct flock fl;
+ int cmd;
+
+#ifdef USE_TDB_MUTEX_LOCKING
+ {
+ int ret;
+ if (tdb_mutex_lock(tdb, rw, off, len, waitflag, &ret)) {
+ return ret;
+ }
+ }
+#endif
fl.l_type = rw;
fl.l_whence = SEEK_SET;
fl.l_len = len;
fl.l_pid = 0;
- if (waitflag)
- return fcntl(tdb->fd, F_SETLKW, &fl);
- else
- return fcntl(tdb->fd, F_SETLK, &fl);
+ cmd = waitflag ? F_SETLKW : F_SETLK;
+
+ return fcntl(tdb->fd, cmd, &fl);
}
static int fcntl_unlock(struct tdb_context *tdb, int rw, off_t off, off_t len)
fclose(locks);
#endif
+#ifdef USE_TDB_MUTEX_LOCKING
+ {
+ int ret;
+ if (tdb_mutex_unlock(tdb, rw, off, len, &ret)) {
+ return ret;
+ }
+ }
+#endif
+
fl.l_type = F_UNLCK;
fl.l_whence = SEEK_SET;
fl.l_start = off;
return fcntl(tdb->fd, F_SETLKW, &fl);
}
+/*
+ * Calculate the lock offset for a list
+ *
+ * list -1 is the freelist, otherwise a hash chain.
+ *
+ * Note that we consistently (but without real reason) lock hash chains at an
+ * offset that is 4 bytes below the real offset of the corresponding list head
+ * in the db.
+ *
+ * This is the memory layout of the hashchain array:
+ *
+ * FREELIST_TOP + 0 = freelist
+ * FREELIST_TOP + 4 = hashtbale list 0
+ * FREELIST_TOP + 8 = hashtbale list 1
+ * ...
+ *
+ * Otoh lock_offset computes:
+ *
+ * freelist = FREELIST_TOP - 4
+ * list 0 = FREELIST_TOP + 0
+ * list 1 = FREELIST_TOP + 4
+ * ...
+ *
+ * Unfortunately we can't change this calculation in order to align the locking
+ * offset with the memory layout, as that would make the locking incompatible
+ * between different tdb versions.
+ */
+static tdb_off_t lock_offset(int list)
+{
+ return FREELIST_TOP + 4*list;
+}
+
/* a byte range locking function - return 0 on success
- this functions locks/unlocks 1 byte at the specified offset.
+ this functions locks/unlocks "len" byte at the specified offset.
On error, errno is also set so that errors are passed back properly
- through tdb_open().
+ through tdb_open().
note that a len of zero means lock to end of file
*/
* EAGAIN is an expected return from non-blocking
* locks. */
if (!(flags & TDB_LOCK_PROBE) && errno != EAGAIN) {
- TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock failed (fd=%d) at offset %d rw_type=%d flags=%d len=%d\n",
- tdb->fd, offset, rw_type, flags, (int)len));
+ TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock failed (fd=%d) at offset %u rw_type=%d flags=%d len=%zu\n",
+ tdb->fd, offset, rw_type, flags, len));
}
return -1;
}
} while (ret == -1 && errno == EINTR);
if (ret == -1) {
- TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brunlock failed (fd=%d) at offset %d rw_type=%d len=%d\n",
- tdb->fd, offset, rw_type, (int)len));
+ TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brunlock failed (fd=%d) at offset %u rw_type=%u len=%zu\n",
+ tdb->fd, offset, rw_type, len));
}
return ret;
}
/*
- 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
- deadlock detection and claim a deadlock when progress can be
- made. For those OSes we may loop for a while.
-*/
-int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len)
+ * Do a tdb_brlock in a loop. Some OSes (such as solaris) have too
+ * conservative deadlock detection and claim a deadlock when progress can be
+ * made. For those OSes we may loop for a while.
+ */
+
+static int tdb_brlock_retry(struct tdb_context *tdb,
+ int rw_type, tdb_off_t offset, size_t len,
+ enum tdb_lock_flags flags)
{
int count = 1000;
+
while (count--) {
struct timeval tv;
- if (tdb_brlock(tdb, F_WRLCK, offset, len,
- TDB_LOCK_WAIT|TDB_LOCK_PROBE) == 0) {
+ int ret;
+
+ ret = tdb_brlock(tdb, rw_type, offset, len, flags);
+ if (ret == 0) {
return 0;
}
if (errno != EDEADLK) {
tv.tv_usec = 1;
select(0, NULL, NULL, NULL, &tv);
}
- TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock_upgrade failed at offset %d\n", offset));
return -1;
}
-/* list -1 is the alloc list, otherwise a hash chain. */
-static tdb_off_t lock_offset(int list)
+/*
+ upgrade a read lock to a write lock.
+*/
+int tdb_allrecord_upgrade(struct tdb_context *tdb)
{
- return FREELIST_TOP + 4*list;
+ int ret;
+
+ if (tdb->allrecord_lock.count != 1) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR,
+ "tdb_allrecord_upgrade failed: count %u too high\n",
+ tdb->allrecord_lock.count));
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+
+ if (tdb->allrecord_lock.off != 1) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR,
+ "tdb_allrecord_upgrade failed: already upgraded?\n"));
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+
+ if (tdb_have_mutexes(tdb)) {
+ ret = tdb_mutex_allrecord_upgrade(tdb);
+ if (ret == -1) {
+ goto fail;
+ }
+ ret = tdb_brlock_retry(tdb, F_WRLCK, lock_offset(tdb->hash_size),
+ 0, TDB_LOCK_WAIT|TDB_LOCK_PROBE);
+ if (ret == -1) {
+ tdb_mutex_allrecord_downgrade(tdb);
+ }
+ } else {
+ ret = tdb_brlock_retry(tdb, F_WRLCK, FREELIST_TOP, 0,
+ TDB_LOCK_WAIT|TDB_LOCK_PROBE);
+ }
+
+ if (ret == 0) {
+ tdb->allrecord_lock.ltype = F_WRLCK;
+ tdb->allrecord_lock.off = 0;
+ return 0;
+ }
+fail:
+ TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_allrecord_upgrade failed\n"));
+ return -1;
}
static struct tdb_lock_type *find_nestlock(struct tdb_context *tdb,
tdb_off_t offset)
{
- unsigned int i;
+ int i;
for (i=0; i<tdb->num_lockrecs; i++) {
if (tdb->lockrecs[i].off == offset) {
{
struct tdb_lock_type *new_lck;
- if (offset >= lock_offset(tdb->header.hash_size)) {
+ if (offset >= lock_offset(tdb->hash_size)) {
tdb->ecode = TDB_ERR_LOCK;
TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_lock: invalid offset %u for ltype=%d\n",
offset, ltype));
new_lck = find_nestlock(tdb, offset);
if (new_lck) {
+ if ((new_lck->ltype == F_RDLCK) && (ltype == F_WRLCK)) {
+ if (!tdb_have_mutexes(tdb)) {
+ int ret;
+ /*
+ * Upgrade the underlying fcntl
+ * lock. Mutexes don't do readlocks,
+ * so this only applies to fcntl
+ * locking.
+ */
+ ret = tdb_brlock(tdb, ltype, offset, 1, flags);
+ if (ret != 0) {
+ return ret;
+ }
+ }
+ new_lck->ltype = F_WRLCK;
+ }
/*
* Just increment the in-memory struct, posix locks
* don't stack.
return 0;
}
- new_lck = (struct tdb_lock_type *)realloc(
- tdb->lockrecs,
- sizeof(*tdb->lockrecs) * (tdb->num_lockrecs+1));
- if (new_lck == NULL) {
- errno = ENOMEM;
- return -1;
+ if (tdb->num_lockrecs == tdb->lockrecs_array_length) {
+ new_lck = (struct tdb_lock_type *)realloc(
+ tdb->lockrecs,
+ sizeof(*tdb->lockrecs) * (tdb->num_lockrecs+1));
+ if (new_lck == NULL) {
+ errno = ENOMEM;
+ return -1;
+ }
+ tdb->lockrecs_array_length = tdb->num_lockrecs+1;
+ tdb->lockrecs = new_lck;
}
- tdb->lockrecs = new_lck;
/* Since fcntl locks don't nest, we do a lock for the first one,
and simply bump the count for future ones */
- if (tdb->methods->brlock(tdb, ltype, offset, 1, flags)) {
+ if (tdb_brlock(tdb, ltype, offset, 1, flags)) {
return -1;
}
- tdb->num_locks++;
+ new_lck = &tdb->lockrecs[tdb->num_lockrecs];
- tdb->lockrecs[tdb->num_lockrecs].off = offset;
- tdb->lockrecs[tdb->num_lockrecs].count = 1;
- tdb->lockrecs[tdb->num_lockrecs].ltype = ltype;
- tdb->num_lockrecs += 1;
+ new_lck->off = offset;
+ new_lck->count = 1;
+ new_lck->ltype = ltype;
+ tdb->num_lockrecs++;
return 0;
}
-/* lock a list in the database. list -1 is the alloc list */
-int tdb_lock(struct tdb_context *tdb, int list, int ltype)
+static int tdb_lock_and_recover(struct tdb_context *tdb)
{
int ret;
- /* a allrecord lock allows us to avoid per chain locks */
- if (tdb->allrecord_lock.count &&
- (ltype == tdb->allrecord_lock.ltype || ltype == F_RDLCK)) {
- return 0;
+ /* 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->allrecord_lock.count) {
- tdb->ecode = TDB_ERR_LOCK;
- ret = -1;
- } else {
- ret = tdb_nest_lock(tdb, lock_offset(list), ltype,
- TDB_LOCK_WAIT);
- }
- if (ret) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock failed on list %d "
- "ltype=%d (%s)\n", list, ltype, strerror(errno)));
+ 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;
}
-/* lock a list in the database. list -1 is the alloc list. non-blocking lock */
-int tdb_lock_nonblock(struct tdb_context *tdb, int list, int ltype)
+static bool have_data_locks(const struct tdb_context *tdb)
{
- /* a allrecord lock allows us to avoid per chain locks */
- if (tdb->allrecord_lock.count &&
- (ltype == tdb->allrecord_lock.ltype || ltype == F_RDLCK)) {
+ int i;
+
+ for (i = 0; i < tdb->num_lockrecs; i++) {
+ if (tdb->lockrecs[i].off >= lock_offset(-1))
+ return true;
+ }
+ return false;
+}
+
+/*
+ * A allrecord lock allows us to avoid per chain locks. Check if the allrecord
+ * lock is strong enough.
+ */
+static int tdb_lock_covered_by_allrecord_lock(struct tdb_context *tdb,
+ int ltype)
+{
+ if (ltype == F_RDLCK) {
+ /*
+ * The allrecord_lock is equal (F_RDLCK) or stronger
+ * (F_WRLCK). Pass.
+ */
return 0;
}
- if (tdb->allrecord_lock.count) {
+ if (tdb->allrecord_lock.ltype == F_RDLCK) {
+ /*
+ * We ask for ltype==F_WRLCK, but the allrecord_lock
+ * is too weak. We can't upgrade here, so fail.
+ */
tdb->ecode = TDB_ERR_LOCK;
return -1;
}
- return tdb_nest_lock(tdb, lock_offset(list), ltype, TDB_LOCK_NOWAIT);
+ /*
+ * Asking for F_WRLCK, allrecord is F_WRLCK as well. Pass.
+ */
+ return 0;
+}
+
+static int tdb_lock_list(struct tdb_context *tdb, int list, int ltype,
+ enum tdb_lock_flags waitflag)
+{
+ int ret;
+ bool check = false;
+
+ if (tdb->allrecord_lock.count) {
+ return tdb_lock_covered_by_allrecord_lock(tdb, ltype);
+ }
+
+ /*
+ * Check for recoveries: Someone might have kill -9'ed a process
+ * during a commit.
+ */
+ check = !have_data_locks(tdb);
+ ret = tdb_nest_lock(tdb, lock_offset(list), ltype, waitflag);
+
+ if (ret == 0 && check && tdb_needs_recovery(tdb)) {
+ tdb_nest_unlock(tdb, lock_offset(list), ltype, false);
+
+ if (tdb_lock_and_recover(tdb) == -1) {
+ return -1;
+ }
+ return tdb_lock_list(tdb, list, ltype, waitflag);
+ }
+ return ret;
+}
+
+/* lock a list in the database. list -1 is the alloc list */
+int tdb_lock(struct tdb_context *tdb, int list, int ltype)
+{
+ int ret;
+
+ ret = tdb_lock_list(tdb, list, ltype, TDB_LOCK_WAIT);
+ if (ret) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock failed on list %d "
+ "ltype=%d (%s)\n", list, ltype, strerror(errno)));
+ }
+ return ret;
+}
+
+/* lock a list in the database. list -1 is the alloc list. non-blocking lock */
+_PUBLIC_ int tdb_lock_nonblock(struct tdb_context *tdb, int list, int ltype)
+{
+ return tdb_lock_list(tdb, list, ltype, TDB_LOCK_NOWAIT);
}
return 0;
/* Sanity checks */
- if (offset >= lock_offset(tdb->header.hash_size)) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: offset %u invalid (%d)\n", offset, tdb->header.hash_size));
+ if (offset >= lock_offset(tdb->hash_size)) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: offset %u invalid (%d)\n", offset, tdb->hash_size));
return ret;
}
if (mark_lock) {
ret = 0;
} else {
- ret = tdb->methods->brunlock(tdb, ltype, offset, 1);
+ ret = tdb_brunlock(tdb, ltype, offset, 1);
}
- tdb->num_locks--;
/*
* Shrink the array by overwriting the element just unlocked with the
* last array element.
*/
-
- if (tdb->num_lockrecs > 1) {
- *lck = tdb->lockrecs[tdb->num_lockrecs-1];
- }
- tdb->num_lockrecs -= 1;
+ *lck = tdb->lockrecs[--tdb->num_lockrecs];
/*
* We don't bother with realloc when the array shrinks, but if we have
* a completely idle tdb we should get rid of the locked array.
*/
- if (tdb->num_lockrecs == 0) {
- SAFE_FREE(tdb->lockrecs);
- }
-
if (ret)
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: An error occurred unlocking!\n"));
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: An error occurred unlocking!\n"));
return ret;
}
-int tdb_unlock(struct tdb_context *tdb, int list, int ltype)
+_PUBLIC_ int tdb_unlock(struct tdb_context *tdb, int list, int ltype)
{
/* a global lock allows us to avoid per chain locks */
- if (tdb->allrecord_lock.count &&
- (ltype == tdb->allrecord_lock.ltype || ltype == F_RDLCK)) {
- return 0;
- }
-
if (tdb->allrecord_lock.count) {
- tdb->ecode = TDB_ERR_LOCK;
- return -1;
+ return tdb_lock_covered_by_allrecord_lock(tdb, ltype);
}
return tdb_nest_unlock(tdb, lock_offset(list), ltype, false);
/*
get the transaction lock
*/
-int tdb_transaction_lock(struct tdb_context *tdb, int ltype)
+int tdb_transaction_lock(struct tdb_context *tdb, int ltype,
+ enum tdb_lock_flags lockflags)
{
- return tdb_nest_lock(tdb, TRANSACTION_LOCK, ltype, TDB_LOCK_WAIT);
+ return tdb_nest_lock(tdb, TRANSACTION_LOCK, ltype, lockflags);
}
/*
return tdb_nest_unlock(tdb, TRANSACTION_LOCK, ltype, false);
}
-
-
-
-/* lock/unlock entire database */
-static int _tdb_lockall(struct tdb_context *tdb, int ltype,
- enum tdb_lock_flags flags)
+/* Returns 0 if all done, -1 if error, 1 if ok. */
+static int tdb_allrecord_check(struct tdb_context *tdb, int ltype,
+ enum tdb_lock_flags flags, bool upgradable)
{
/* There are no locks on read-only dbs */
if (tdb->read_only || tdb->traverse_read) {
return -1;
}
- if (tdb->allrecord_lock.count && tdb->allrecord_lock.ltype == ltype) {
+ if (tdb->allrecord_lock.count &&
+ tdb->allrecord_lock.ltype == (uint32_t)ltype) {
tdb->allrecord_lock.count++;
return 0;
}
return -1;
}
- if (tdb->methods->brlock(tdb, ltype,
- FREELIST_TOP, 4*tdb->header.hash_size,
- flags)) {
- if (flags & TDB_LOCK_WAIT) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lockall failed (%s)\n", strerror(errno)));
+ if (upgradable && ltype != F_RDLCK) {
+ /* tdb error: you can't upgrade a write lock! */
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+ return 1;
+}
+
+/* We only need to lock individual bytes, but Linux merges consecutive locks
+ * so we lock in contiguous ranges. */
+static int tdb_chainlock_gradual(struct tdb_context *tdb,
+ int ltype, enum tdb_lock_flags flags,
+ size_t off, size_t len)
+{
+ int ret;
+ enum tdb_lock_flags nb_flags = (flags & ~TDB_LOCK_WAIT);
+
+ if (len <= 4) {
+ /* Single record. Just do blocking lock. */
+ return tdb_brlock(tdb, ltype, off, len, flags);
+ }
+
+ /* First we try non-blocking. */
+ ret = tdb_brlock(tdb, ltype, off, len, nb_flags);
+ if (ret == 0) {
+ return 0;
+ }
+
+ /* Try locking first half, then second. */
+ ret = tdb_chainlock_gradual(tdb, ltype, flags, off, len / 2);
+ if (ret == -1)
+ return -1;
+
+ ret = tdb_chainlock_gradual(tdb, ltype, flags,
+ off + len / 2, len - len / 2);
+ if (ret == -1) {
+ tdb_brunlock(tdb, ltype, off, len / 2);
+ return -1;
+ }
+ return 0;
+}
+
+/* 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 tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
+ enum tdb_lock_flags flags, bool upgradable)
+{
+ int ret;
+
+ switch (tdb_allrecord_check(tdb, ltype, flags, upgradable)) {
+ case -1:
+ return -1;
+ case 0:
+ return 0;
+ }
+
+ /* We cover two kinds of locks:
+ * 1) Normal chain locks. Taken for almost all operations.
+ * 2) 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. */
+
+ if (tdb_have_mutexes(tdb)) {
+ ret = tdb_mutex_allrecord_lock(tdb, ltype, flags);
+ } else {
+ ret = tdb_chainlock_gradual(tdb, ltype, flags, FREELIST_TOP,
+ tdb->hash_size * 4);
+ }
+
+ if (ret == -1) {
+ return -1;
+ }
+
+ /* Grab individual record locks. */
+ if (tdb_brlock(tdb, ltype, lock_offset(tdb->hash_size), 0,
+ flags) == -1) {
+ if (tdb_have_mutexes(tdb)) {
+ tdb_mutex_allrecord_unlock(tdb);
+ } else {
+ tdb_brunlock(tdb, ltype, FREELIST_TOP,
+ tdb->hash_size * 4);
}
return -1;
}
tdb->allrecord_lock.count = 1;
- tdb->allrecord_lock.ltype = ltype;
+ /* If it's upgradable, it's actually exclusive so we can treat
+ * it as a write lock. */
+ tdb->allrecord_lock.ltype = upgradable ? F_WRLCK : ltype;
+ tdb->allrecord_lock.off = upgradable;
+
+ if (tdb_needs_recovery(tdb)) {
+ bool mark = flags & TDB_LOCK_MARK_ONLY;
+ tdb_allrecord_unlock(tdb, ltype, mark);
+ if (mark) {
+ tdb->ecode = TDB_ERR_LOCK;
+ TDB_LOG((tdb, TDB_DEBUG_ERROR,
+ "tdb_lockall_mark cannot do recovery\n"));
+ return -1;
+ }
+ if (tdb_lock_and_recover(tdb) == -1) {
+ return -1;
+ }
+ return tdb_allrecord_lock(tdb, ltype, flags, upgradable);
+ }
return 0;
}
/* unlock entire db */
-static int _tdb_unlockall(struct tdb_context *tdb, int ltype, bool mark_lock)
+int tdb_allrecord_unlock(struct tdb_context *tdb, int ltype, bool mark_lock)
{
/* There are no locks on read-only dbs */
if (tdb->read_only || tdb->traverse_read) {
return -1;
}
- if (tdb->allrecord_lock.ltype != ltype || tdb->allrecord_lock.count == 0) {
+ if (tdb->allrecord_lock.count == 0) {
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+
+ /* Upgradable locks are marked as write locks. */
+ if (tdb->allrecord_lock.ltype != (uint32_t)ltype
+ && (!tdb->allrecord_lock.off || ltype != F_RDLCK)) {
tdb->ecode = TDB_ERR_LOCK;
return -1;
}
return 0;
}
- if (!mark_lock &&
- tdb->methods->brunlock(tdb, ltype,
- FREELIST_TOP, 4*tdb->header.hash_size)) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlockall failed (%s)\n", strerror(errno)));
- return -1;
+ if (!mark_lock) {
+ int ret;
+
+ if (tdb_have_mutexes(tdb)) {
+ ret = tdb_mutex_allrecord_unlock(tdb);
+ if (ret == 0) {
+ ret = tdb_brunlock(tdb, ltype,
+ lock_offset(tdb->hash_size),
+ 0);
+ }
+ } else {
+ ret = tdb_brunlock(tdb, ltype, FREELIST_TOP, 0);
+ }
+
+ if (ret != 0) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlockall failed "
+ "(%s)\n", strerror(errno)));
+ return -1;
+ }
}
tdb->allrecord_lock.count = 0;
}
/* lock entire database with write lock */
-int tdb_lockall(struct tdb_context *tdb)
+_PUBLIC_ int tdb_lockall(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall");
- return _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_WAIT);
+ return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
}
/* lock entire database with write lock - mark only */
-int tdb_lockall_mark(struct tdb_context *tdb)
+_PUBLIC_ int tdb_lockall_mark(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_mark");
- return _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_MARK_ONLY);
+ return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_MARK_ONLY, false);
}
/* unlock entire database with write lock - unmark only */
-int tdb_lockall_unmark(struct tdb_context *tdb)
+_PUBLIC_ int tdb_lockall_unmark(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_unmark");
- return _tdb_unlockall(tdb, F_WRLCK, true);
+ return tdb_allrecord_unlock(tdb, F_WRLCK, true);
}
/* lock entire database with write lock - nonblocking varient */
-int tdb_lockall_nonblock(struct tdb_context *tdb)
+_PUBLIC_ int tdb_lockall_nonblock(struct tdb_context *tdb)
{
- int ret = _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_NOWAIT);
+ 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)
+_PUBLIC_ int tdb_unlockall(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_unlockall");
- return _tdb_unlockall(tdb, F_WRLCK, false);
+ return tdb_allrecord_unlock(tdb, F_WRLCK, false);
}
/* lock entire database with read lock */
-int tdb_lockall_read(struct tdb_context *tdb)
+_PUBLIC_ int tdb_lockall_read(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_read");
- return _tdb_lockall(tdb, F_RDLCK, TDB_LOCK_WAIT);
+ 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)
+_PUBLIC_ int tdb_lockall_read_nonblock(struct tdb_context *tdb)
{
- int ret = _tdb_lockall(tdb, F_RDLCK, TDB_LOCK_NOWAIT);
+ int ret = tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_NOWAIT, false);
tdb_trace_ret(tdb, "tdb_lockall_read_nonblock", ret);
return ret;
}
/* unlock entire database with read lock */
-int tdb_unlockall_read(struct tdb_context *tdb)
+_PUBLIC_ int tdb_unlockall_read(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_unlockall_read");
- return _tdb_unlockall(tdb, F_RDLCK, false);
+ return tdb_allrecord_unlock(tdb, F_RDLCK, false);
}
/* 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)
+_PUBLIC_ int tdb_chainlock(struct tdb_context *tdb, TDB_DATA key)
{
int ret = tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK);
tdb_trace_1rec(tdb, "tdb_chainlock", key);
/* 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)
+_PUBLIC_ int tdb_chainlock_nonblock(struct tdb_context *tdb, TDB_DATA key)
{
int ret = tdb_lock_nonblock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK);
tdb_trace_1rec_ret(tdb, "tdb_chainlock_nonblock", key, ret);
}
/* mark a chain as locked without actually locking it. Warning! use with great caution! */
-int tdb_chainlock_mark(struct tdb_context *tdb, TDB_DATA key)
+_PUBLIC_ int tdb_chainlock_mark(struct tdb_context *tdb, TDB_DATA key)
{
int ret = tdb_nest_lock(tdb, lock_offset(BUCKET(tdb->hash_fn(&key))),
F_WRLCK, TDB_LOCK_MARK_ONLY);
}
/* unmark a chain as locked without actually locking it. Warning! use with great caution! */
-int tdb_chainlock_unmark(struct tdb_context *tdb, TDB_DATA key)
+_PUBLIC_ int tdb_chainlock_unmark(struct tdb_context *tdb, TDB_DATA key)
{
tdb_trace_1rec(tdb, "tdb_chainlock_unmark", key);
return tdb_nest_unlock(tdb, lock_offset(BUCKET(tdb->hash_fn(&key))),
F_WRLCK, true);
}
-int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key)
+_PUBLIC_ int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key)
{
tdb_trace_1rec(tdb, "tdb_chainunlock", key);
return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK);
}
-int tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key)
+_PUBLIC_ int tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key)
{
int ret;
ret = tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_RDLCK);
return ret;
}
-int tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key)
+_PUBLIC_ int tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key)
{
tdb_trace_1rec(tdb, "tdb_chainunlock_read", key);
return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_RDLCK);
}
-
+_PUBLIC_ int tdb_chainlock_read_nonblock(struct tdb_context *tdb, TDB_DATA key)
+{
+ int ret = tdb_lock_nonblock(tdb, BUCKET(tdb->hash_fn(&key)), F_RDLCK);
+ tdb_trace_1rec_ret(tdb, "tdb_chainlock_read_nonblock", key, ret);
+ return ret;
+}
/* 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->methods->brlock(tdb, F_RDLCK, off, 1, TDB_LOCK_WAIT) : 0;
+ return off ? tdb_brlock(tdb, F_RDLCK, off, 1, TDB_LOCK_WAIT) : 0;
}
/*
for (i = &tdb->travlocks; i; i = i->next)
if (i->off == off)
return -1;
- return tdb->methods->brlock(tdb, F_WRLCK, off, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
+ 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)
{
- return tdb->methods->brunlock(tdb, F_WRLCK, off, 1);
+ 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 */
for (i = &tdb->travlocks; i; i = i->next)
if (i->off == off)
count++;
- return (count == 1 ? tdb->methods->brunlock(tdb, F_RDLCK, off, 1) : 0);
+ return (count == 1 ? tdb_brunlock(tdb, F_RDLCK, off, 1) : 0);
}
bool tdb_have_extra_locks(struct tdb_context *tdb)
{
unsigned int extra = tdb->num_lockrecs;
- if (tdb->allrecord_lock.count) {
+ /* A transaction holds the lock for all records. */
+ if (!tdb->transaction && tdb->allrecord_lock.count) {
return true;
}
+ /* We always hold the active lock if CLEAR_IF_FIRST. */
+ if (find_nestlock(tdb, ACTIVE_LOCK)) {
+ extra--;
+ }
+
/* In a transaction, we expect to hold the transaction lock */
if (tdb->transaction && find_nestlock(tdb, TRANSACTION_LOCK)) {
extra--;
}
/* The transaction code uses this to remove all locks. */
-void tdb_release_extra_locks(struct tdb_context *tdb)
+void tdb_release_transaction_locks(struct tdb_context *tdb)
{
- unsigned int i, extra = 0;
+ int i;
+ unsigned int active = 0;
if (tdb->allrecord_lock.count != 0) {
- tdb_brunlock(tdb, tdb->allrecord_lock.ltype,
- FREELIST_TOP, 4*tdb->header.hash_size);
+ tdb_allrecord_unlock(tdb, tdb->allrecord_lock.ltype, false);
tdb->allrecord_lock.count = 0;
}
for (i=0;i<tdb->num_lockrecs;i++) {
struct tdb_lock_type *lck = &tdb->lockrecs[i];
- if (tdb->transaction && lck->off == TRANSACTION_LOCK) {
- tdb->lockrecs[extra++] = *lck;
+ /* Don't release the active lock! Copy it to first entry. */
+ if (lck->off == ACTIVE_LOCK) {
+ tdb->lockrecs[active++] = *lck;
} else {
tdb_brunlock(tdb, lck->ltype, lck->off, 1);
}
}
- tdb->num_locks = extra;
- tdb->num_lockrecs = extra;
- if (tdb->num_lockrecs == 0) {
- SAFE_FREE(tdb->lockrecs);
- }
+ tdb->num_lockrecs = active;
+}
+
+/* Following functions are added specifically to support CTDB. */
+
+/* Don't do actual fcntl locking, just mark tdb locked */
+int tdb_transaction_write_lock_mark(struct tdb_context *tdb);
+_PUBLIC_ int tdb_transaction_write_lock_mark(struct tdb_context *tdb)
+{
+ return tdb_transaction_lock(tdb, F_WRLCK, TDB_LOCK_MARK_ONLY);
+}
+
+/* Don't do actual fcntl unlocking, just mark tdb unlocked */
+int tdb_transaction_write_lock_unmark(struct tdb_context *tdb);
+_PUBLIC_ int tdb_transaction_write_lock_unmark(struct tdb_context *tdb)
+{
+ return tdb_nest_unlock(tdb, TRANSACTION_LOCK, F_WRLCK, true);
}
git.samba.org / samba.git / blobdiff