#include <assert.h>
#include <ccan/build_assert/build_assert.h>
+/* If we were threaded, we could wait for unlock, but we're not, so fail. */
+static enum TDB_ERROR owner_conflict(struct tdb_context *tdb, const char *call)
+{
+ return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
+ "%s: lock owned by another tdb in this process.",
+ call);
+}
+
+/* If we fork, we no longer really own locks. */
+static bool check_lock_pid(struct tdb_context *tdb,
+ const char *call, bool log)
+{
+ /* No locks? No problem! */
+ if (tdb->file->allrecord_lock.count == 0
+ && tdb->file->num_lockrecs == 0) {
+ return true;
+ }
+
+ /* No fork? No problem! */
+ if (tdb->file->locker == getpid()) {
+ return true;
+ }
+
+ if (log) {
+ tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
+ "%s: fork() detected after lock acquisition!"
+ " (%u vs %u)", call, tdb->file->locker, getpid());
+ }
+ return false;
+}
+
static int fcntl_lock(struct tdb_context *tdb,
int rw, off_t off, off_t len, bool waitflag)
{
fl.l_len = len;
fl.l_pid = 0;
+ if (tdb->file->allrecord_lock.count == 0
+ && tdb->file->num_lockrecs == 0) {
+ tdb->file->locker = getpid();
+ }
+
add_stat(tdb, lock_lowlevel, 1);
if (waitflag)
- return fcntl(tdb->fd, F_SETLKW, &fl);
+ return fcntl(tdb->file->fd, F_SETLKW, &fl);
else {
add_stat(tdb, lock_nonblock, 1);
- return fcntl(tdb->fd, F_SETLK, &fl);
+ return fcntl(tdb->file->fd, F_SETLK, &fl);
}
}
fl.l_len = len;
fl.l_pid = 0;
- return fcntl(tdb->fd, F_SETLKW, &fl);
+ return fcntl(tdb->file->fd, F_SETLKW, &fl);
}
/* a byte range locking function - return 0 on success
- this functions locks/unlocks 1 byte at the specified offset.
+ this functions locks len bytes at the specified offset.
note that a len of zero means lock to end of file
*/
"tdb_brlock failed (fd=%d) at"
" offset %zu rw_type=%d flags=%d len=%zu:"
" %s",
- tdb->fd, (size_t)offset, rw_type,
+ tdb->file->fd, (size_t)offset, rw_type,
flags, (size_t)len, strerror(errno));
}
return TDB_ERR_LOCK;
ret = fcntl_unlock(tdb, rw_type, offset, len);
} while (ret == -1 && errno == EINTR);
- if (ret == -1) {
+ /* If we fail, *then* we verify that we owned the lock. If not, ok. */
+ if (ret == -1 && check_lock_pid(tdb, "tdb_brunlock", false)) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_brunlock failed (fd=%d) at offset %zu"
" rw_type=%d len=%zu",
- tdb->fd, (size_t)offset, rw_type,
+ tdb->file->fd, (size_t)offset, rw_type,
(size_t)len);
}
return TDB_SUCCESS;
{
int count = 1000;
- if (tdb->allrecord_lock.count != 1) {
+ if (!check_lock_pid(tdb, "tdb_transaction_prepare_commit", true))
+ return TDB_ERR_LOCK;
+
+ if (tdb->file->allrecord_lock.count != 1) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_allrecord_upgrade failed:"
" count %u too high",
- tdb->allrecord_lock.count);
+ tdb->file->allrecord_lock.count);
}
- if (tdb->allrecord_lock.off != 1) {
+ if (tdb->file->allrecord_lock.off != 1) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_allrecord_upgrade failed:"
" already upgraded?");
}
+ if (tdb->file->allrecord_lock.owner != tdb) {
+ return owner_conflict(tdb, "tdb_allrecord_upgrade");
+ }
+
while (count--) {
struct timeval tv;
if (tdb_brlock(tdb, F_WRLCK,
TDB_HASH_LOCK_START, 0,
TDB_LOCK_WAIT|TDB_LOCK_PROBE) == TDB_SUCCESS) {
- tdb->allrecord_lock.ltype = F_WRLCK;
- tdb->allrecord_lock.off = 0;
+ tdb->file->allrecord_lock.ltype = F_WRLCK;
+ tdb->file->allrecord_lock.off = 0;
return TDB_SUCCESS;
}
if (errno != EDEADLK) {
"tdb_allrecord_upgrade failed");
}
-static struct tdb_lock_type *find_nestlock(struct tdb_context *tdb,
- tdb_off_t offset)
+static struct tdb_lock *find_nestlock(struct tdb_context *tdb, tdb_off_t offset,
+ const struct tdb_context *owner)
{
unsigned int i;
- for (i=0; i<tdb->num_lockrecs; i++) {
- if (tdb->lockrecs[i].off == offset) {
- return &tdb->lockrecs[i];
+ for (i=0; i<tdb->file->num_lockrecs; i++) {
+ if (tdb->file->lockrecs[i].off == offset) {
+ if (owner && tdb->file->lockrecs[i].owner != owner)
+ return NULL;
+ return &tdb->file->lockrecs[i];
}
}
return NULL;
{
enum TDB_ERROR ecode;
+ if (!check_lock_pid(tdb, "tdb_transaction_prepare_commit", true))
+ return TDB_ERR_LOCK;
+
ecode = tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK,
false);
if (ecode != TDB_SUCCESS) {
tdb_allrecord_unlock(tdb, F_WRLCK);
return ecode;
}
- if (tdb_transaction_recover(tdb) == -1) {
- ecode = tdb->ecode;
- }
-
+ ecode = tdb_transaction_recover(tdb);
tdb_unlock_open(tdb);
tdb_allrecord_unlock(tdb, F_WRLCK);
tdb_off_t offset, int ltype,
enum tdb_lock_flags flags)
{
- struct tdb_lock_type *new_lck;
+ struct tdb_lock *new_lck;
enum TDB_ERROR ecode;
- if (offset > TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE + tdb->map_size / 8) {
+ if (offset > (TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE
+ + tdb->file->map_size / 8)) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_nest_lock: invalid offset %zu ltype=%d",
(size_t)offset, ltype);
if (tdb->flags & TDB_NOLOCK)
return TDB_SUCCESS;
+ if (!check_lock_pid(tdb, "tdb_nest_lock", true)) {
+ return TDB_ERR_LOCK;
+ }
+
add_stat(tdb, locks, 1);
- new_lck = find_nestlock(tdb, offset);
+ new_lck = find_nestlock(tdb, offset, NULL);
if (new_lck) {
+ if (new_lck->owner != tdb) {
+ return owner_conflict(tdb, "tdb_nest_lock");
+ }
+
if (new_lck->ltype == F_RDLCK && ltype == F_WRLCK) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_nest_lock:"
return TDB_SUCCESS;
}
- if (tdb->num_lockrecs
+ if (tdb->file->num_lockrecs
&& offset >= TDB_HASH_LOCK_START
&& offset < TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_nest_lock: already have a hash lock?");
}
- new_lck = (struct tdb_lock_type *)realloc(
- tdb->lockrecs,
- sizeof(*tdb->lockrecs) * (tdb->num_lockrecs+1));
+ new_lck = (struct tdb_lock *)realloc(
+ tdb->file->lockrecs,
+ sizeof(*tdb->file->lockrecs) * (tdb->file->num_lockrecs+1));
if (new_lck == NULL) {
return tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
"tdb_nest_lock:"
" unable to allocate %zu lock struct",
- tdb->num_lockrecs + 1);
+ tdb->file->num_lockrecs + 1);
}
- tdb->lockrecs = new_lck;
+ tdb->file->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 */
/* 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);
-
- ecode = tdb_lock_and_recover(tdb);
- if (ecode == TDB_SUCCESS) {
- ecode = tdb_brlock(tdb, ltype, offset, 1, flags);
- }
- if (ecode != TDB_SUCCESS) {
- return ecode;
+ && tdb->file->num_lockrecs == 0) {
+ tdb_bool_err berr = tdb_needs_recovery(tdb);
+ if (berr != false) {
+ tdb_brunlock(tdb, ltype, offset, 1);
+
+ if (berr < 0)
+ return berr;
+ ecode = tdb_lock_and_recover(tdb);
+ if (ecode == TDB_SUCCESS) {
+ ecode = tdb_brlock(tdb, ltype, offset, 1,
+ flags);
+ }
+ if (ecode != TDB_SUCCESS) {
+ return ecode;
+ }
}
}
- tdb->lockrecs[tdb->num_lockrecs].off = offset;
- tdb->lockrecs[tdb->num_lockrecs].count = 1;
- tdb->lockrecs[tdb->num_lockrecs].ltype = ltype;
- tdb->num_lockrecs++;
+ tdb->file->lockrecs[tdb->file->num_lockrecs].owner = tdb;
+ tdb->file->lockrecs[tdb->file->num_lockrecs].off = offset;
+ tdb->file->lockrecs[tdb->file->num_lockrecs].count = 1;
+ tdb->file->lockrecs[tdb->file->num_lockrecs].ltype = ltype;
+ tdb->file->num_lockrecs++;
return TDB_SUCCESS;
}
static enum TDB_ERROR tdb_nest_unlock(struct tdb_context *tdb,
tdb_off_t off, int ltype)
{
- struct tdb_lock_type *lck;
+ struct tdb_lock *lck;
enum TDB_ERROR ecode;
if (tdb->flags & TDB_NOLOCK)
return TDB_SUCCESS;
- lck = find_nestlock(tdb, off);
+ lck = find_nestlock(tdb, off, tdb);
if ((lck == NULL) || (lck->count == 0)) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_nest_unlock: no lock for %zu",
* Shrink the array by overwriting the element just unlocked with the
* last array element.
*/
- *lck = tdb->lockrecs[--tdb->num_lockrecs];
+ *lck = tdb->file->lockrecs[--tdb->file->num_lockrecs];
return ecode;
}
enum tdb_lock_flags flags, bool upgradable)
{
enum TDB_ERROR ecode;
+ tdb_bool_err berr;
- /* FIXME: There are no locks on read-only dbs */
- if (tdb->read_only) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
- "tdb_allrecord_lock: read-only");
- }
-
- if (tdb->allrecord_lock.count
- && (ltype == F_RDLCK || tdb->allrecord_lock.ltype == F_WRLCK)) {
- tdb->allrecord_lock.count++;
+ if (tdb->flags & TDB_NOLOCK)
return TDB_SUCCESS;
+
+ if (!check_lock_pid(tdb, "tdb_allrecord_lock", true)) {
+ return TDB_ERR_LOCK;
}
- if (tdb->allrecord_lock.count) {
+ if (tdb->file->allrecord_lock.count) {
+ if (tdb->file->allrecord_lock.owner != tdb) {
+ return owner_conflict(tdb, "tdb_allrecord_lock");
+ }
+
+ if (ltype == F_RDLCK
+ || tdb->file->allrecord_lock.ltype == F_WRLCK) {
+ tdb->file->allrecord_lock.count++;
+ return TDB_SUCCESS;
+ }
+
/* a global lock of a different type exists */
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
"tdb_allrecord_lock: already have %s lock",
- tdb->allrecord_lock.ltype == F_RDLCK
+ tdb->file->allrecord_lock.ltype == F_RDLCK
? "read" : "write");
}
return ecode;
}
- tdb->allrecord_lock.count = 1;
+ tdb->file->allrecord_lock.owner = tdb;
+ tdb->file->allrecord_lock.count = 1;
/* 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;
+ tdb->file->allrecord_lock.ltype = upgradable ? F_WRLCK : ltype;
+ tdb->file->allrecord_lock.off = upgradable;
/* Now check for needing recovery. */
- if (!(flags & TDB_LOCK_NOCHECK) && unlikely(tdb_needs_recovery(tdb))) {
- tdb_allrecord_unlock(tdb, ltype);
- ecode = tdb_lock_and_recover(tdb);
- if (ecode != TDB_SUCCESS) {
- return ecode;
- }
- goto again;
- }
+ if (flags & TDB_LOCK_NOCHECK)
+ return TDB_SUCCESS;
- return TDB_SUCCESS;
+ berr = tdb_needs_recovery(tdb);
+ if (likely(berr == false))
+ return TDB_SUCCESS;
+
+ tdb_allrecord_unlock(tdb, ltype);
+ if (berr < 0)
+ return berr;
+ ecode = tdb_lock_and_recover(tdb);
+ if (ecode != TDB_SUCCESS) {
+ return ecode;
+ }
+ goto again;
}
enum TDB_ERROR tdb_lock_open(struct tdb_context *tdb, enum tdb_lock_flags flags)
bool tdb_has_open_lock(struct tdb_context *tdb)
{
- return find_nestlock(tdb, TDB_OPEN_LOCK) != NULL;
+ return !(tdb->flags & TDB_NOLOCK)
+ && find_nestlock(tdb, TDB_OPEN_LOCK, tdb) != NULL;
}
enum TDB_ERROR tdb_lock_expand(struct tdb_context *tdb, int ltype)
/* unlock entire db */
void tdb_allrecord_unlock(struct tdb_context *tdb, int ltype)
{
- if (tdb->allrecord_lock.count == 0) {
+ if (tdb->flags & TDB_NOLOCK)
+ return;
+
+ if (tdb->file->allrecord_lock.count == 0) {
tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
"tdb_allrecord_unlock: not locked!");
return;
}
+ if (tdb->file->allrecord_lock.owner != tdb) {
+ tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
+ "tdb_allrecord_unlock: not locked by us!");
+ return;
+ }
+
/* Upgradable locks are marked as write locks. */
- if (tdb->allrecord_lock.ltype != ltype
- && (!tdb->allrecord_lock.off || ltype != F_RDLCK)) {
+ if (tdb->file->allrecord_lock.ltype != ltype
+ && (!tdb->file->allrecord_lock.off || ltype != F_RDLCK)) {
tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_allrecord_unlock: have %s lock",
- tdb->allrecord_lock.ltype == F_RDLCK
+ tdb->file->allrecord_lock.ltype == F_RDLCK
? "read" : "write");
return;
}
- if (tdb->allrecord_lock.count > 1) {
- tdb->allrecord_lock.count--;
+ if (tdb->file->allrecord_lock.count > 1) {
+ tdb->file->allrecord_lock.count--;
return;
}
- tdb->allrecord_lock.count = 0;
- tdb->allrecord_lock.ltype = 0;
+ tdb->file->allrecord_lock.count = 0;
+ tdb->file->allrecord_lock.ltype = 0;
tdb_brunlock(tdb, ltype, TDB_HASH_LOCK_START, 0);
}
bool tdb_has_expansion_lock(struct tdb_context *tdb)
{
- return find_nestlock(tdb, TDB_EXPANSION_LOCK) != NULL;
+ return find_nestlock(tdb, TDB_EXPANSION_LOCK, tdb) != NULL;
}
bool tdb_has_hash_locks(struct tdb_context *tdb)
{
unsigned int i;
- 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))
+ for (i=0; i<tdb->file->num_lockrecs; i++) {
+ if (tdb->file->lockrecs[i].off >= TDB_HASH_LOCK_START
+ && tdb->file->lockrecs[i].off < (TDB_HASH_LOCK_START
+ + TDB_HASH_LOCK_RANGE))
return true;
}
return false;
{
unsigned int i;
- for (i=0; i<tdb->num_lockrecs; i++) {
- if (tdb->lockrecs[i].off
+ if (tdb->flags & TDB_NOLOCK)
+ return false;
+
+ for (i=0; i<tdb->file->num_lockrecs; i++) {
+ if (tdb->file->lockrecs[i].off
> TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE)
return true;
}
+ (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 TDB_SUCCESS;
- }
+ if (tdb->file->allrecord_lock.count) {
+ if (!check_lock_pid(tdb, "tdb_lock_hashes", true))
+ return TDB_ERR_LOCK;
+
+ if (tdb->file->allrecord_lock.owner != tdb)
+ return owner_conflict(tdb, "tdb_lock_hashes");
+ if (ltype == tdb->file->allrecord_lock.ltype
+ || ltype == F_RDLCK) {
+ return TDB_SUCCESS;
+ }
- if (tdb->allrecord_lock.count) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
"tdb_lock_hashes:"
" already have %s allrecordlock",
- tdb->allrecord_lock.ltype == F_RDLCK
+ tdb->file->allrecord_lock.ltype == F_RDLCK
? "read" : "write");
}
unsigned lock = TDB_HASH_LOCK_START
+ (hash_lock >> (64 - TDB_HASH_LOCK_RANGE_BITS));
+ if (tdb->flags & TDB_NOLOCK)
+ return 0;
+
/* a allrecord lock allows us to avoid per chain locks */
- if (tdb->allrecord_lock.count) {
- if (tdb->allrecord_lock.ltype == F_RDLCK
+ if (tdb->file->allrecord_lock.count) {
+ if (tdb->file->allrecord_lock.ltype == F_RDLCK
&& ltype == F_WRLCK) {
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_unlock_hashes RO allrecord!");
{
assert(b_off >= sizeof(struct tdb_header));
+ if (tdb->flags & TDB_NOLOCK)
+ return 0;
+
/* a allrecord lock allows us to avoid per chain locks */
- if (tdb->allrecord_lock.count) {
- if (tdb->allrecord_lock.ltype == F_WRLCK)
+ if (tdb->file->allrecord_lock.count) {
+ if (!check_lock_pid(tdb, "tdb_lock_free_bucket", true))
+ return TDB_ERR_LOCK;
+
+ if (tdb->file->allrecord_lock.ltype == F_WRLCK)
return 0;
return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
"tdb_lock_free_bucket with"
void tdb_unlock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off)
{
- if (tdb->allrecord_lock.count)
+ if (tdb->file->allrecord_lock.count)
return;
tdb_nest_unlock(tdb, free_lock_off(b_off), F_WRLCK);
}
-void tdb_lock_init(struct tdb_context *tdb)
+enum TDB_ERROR tdb_lockall(struct tdb_context *tdb)
+{
+ return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
+}
+
+void tdb_unlockall(struct tdb_context *tdb)
+{
+ tdb_allrecord_unlock(tdb, F_WRLCK);
+}
+
+enum TDB_ERROR tdb_lockall_read(struct tdb_context *tdb)
+{
+ return tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false);
+}
+
+void tdb_unlockall_read(struct tdb_context *tdb)
+{
+ tdb_allrecord_unlock(tdb, F_RDLCK);
+}
+
+void tdb_lock_cleanup(struct tdb_context *tdb)
{
- tdb->num_lockrecs = 0;
- tdb->lockrecs = NULL;
- tdb->allrecord_lock.count = 0;
+ unsigned int i;
+
+ while (tdb->file->allrecord_lock.count
+ && tdb->file->allrecord_lock.owner == tdb) {
+ tdb_allrecord_unlock(tdb, tdb->file->allrecord_lock.ltype);
+ }
+
+ for (i=0; i<tdb->file->num_lockrecs; i++) {
+ if (tdb->file->lockrecs[i].owner == tdb) {
+ tdb_nest_unlock(tdb,
+ tdb->file->lockrecs[i].off,
+ tdb->file->lockrecs[i].ltype);
+ i--;
+ }
+ }
}