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tdb: Allow !CLEAR_IF_FIRST & MUTEX_LOCKING

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This is a prerequisite to allow gencache to run on a non-transactioned
database with mutexes.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
This commit is contained in:
Volker Lendecke 2018-10-22 08:57:00 +02:00 committed by Jeremy Allison
parent e814fb6bcb
commit 72ec893d0a
2 changed files with 42 additions and 56 deletions
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91
lib/tdb/common/open.c
View File

@ -230,8 +230,6 @@ static bool check_header_hash(struct tdb_context *tdb,
static bool tdb_mutex_open_ok(struct tdb_context *tdb,
const struct tdb_header *header)
{
int locked;
if (tdb->flags & TDB_NOLOCK) {
/*
* We don't look at locks, so it does not matter to have a
@ -240,37 +238,6 @@ static bool tdb_mutex_open_ok(struct tdb_context *tdb,
return true;
}
locked = tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK,
TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
if ((locked == -1) && (tdb->ecode == TDB_ERR_LOCK)) {
/*
* CLEAR_IF_FIRST still active. The tdb was created on this
* host, so we can assume the mutex implementation is
* compatible. Important for tools like tdbdump on a still
* open locking.tdb.
*/
goto check_local_settings;
}
/*
* We got the CLEAR_IF_FIRST lock. That means the database was
* potentially copied from somewhere else. The mutex implementation
* might be incompatible.
*/
if (tdb_nest_unlock(tdb, ACTIVE_LOCK, F_WRLCK, false) == -1) {
/*
* Should not happen
*/
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_mutex_open_ok: "
"failed to release ACTIVE_LOCK on %s: %s\n",
tdb->name, strerror(errno)));
return false;
}
check_local_settings:
if (!(tdb->flags & TDB_MUTEX_LOCKING)) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_mutex_open_ok[%s]: "
"Can use mutexes only with "
@ -416,14 +383,6 @@ _PUBLIC_ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int td
* the runtime check for existing tdb's comes later.
*/
if (!(tdb->flags & TDB_CLEAR_IF_FIRST)) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
"invalid flags for %s - TDB_MUTEX_LOCKING "
"requires TDB_CLEAR_IF_FIRST\n", name));
errno = EINVAL;
goto fail;
}
if (tdb->flags & TDB_INTERNAL) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
"invalid flags for %s - TDB_MUTEX_LOCKING and "
@ -632,6 +591,30 @@ _PUBLIC_ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int td
* mutex locking.
*/
tdb->hdr_ofs = header.mutex_size;
if ((!(tdb_flags & TDB_CLEAR_IF_FIRST)) && (!tdb->read_only)) {
/*
* Open an existing mutexed tdb, but without
* CLEAR_IF_FIRST. We need to initialize the
* mutex array and keep the CLEAR_IF_FIRST
* lock locked.
*/
ret = tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK,
TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
locked = (ret == 0);
if (locked) {
ret = tdb_mutex_init(tdb);
if (ret == -1) {
TDB_LOG((tdb,
TDB_DEBUG_FATAL,
"tdb_open_ex: tdb_mutex_init "
"failed for ""%s: %s\n",
name, strerror(errno)));
goto fail;
}
}
}
}
if ((header.magic1_hash == 0) && (header.magic2_hash == 0)) {
@ -708,15 +691,19 @@ _PUBLIC_ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int td
goto fail;
}
}
/* We always need to do this if the CLEAR_IF_FIRST flag is set, even if
we didn't get the initial exclusive lock as we need to let all other
users know we're using it. */
if (locked || (tdb_flags & TDB_CLEAR_IF_FIRST)) {
/*
* We always need to do this if the CLEAR_IF_FIRST
* flag is set, even if we didn't get the initial
* exclusive lock as we need to let all other users
* know we're using it.
*/
if (tdb_flags & TDB_CLEAR_IF_FIRST) {
/* leave this lock in place to indicate it's in use */
if (tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT) == -1) {
ret = tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT);
if (ret == -1) {
goto fail;
}
}
@ -932,7 +919,10 @@ fail:
seek pointer from our parent and to re-establish locks */
_PUBLIC_ int tdb_reopen(struct tdb_context *tdb)
{
return tdb_reopen_internal(tdb, tdb->flags & TDB_CLEAR_IF_FIRST);
bool active_lock;
active_lock = (tdb->flags & (TDB_CLEAR_IF_FIRST|TDB_MUTEX_LOCKING));
return tdb_reopen_internal(tdb, active_lock);
}
/* reopen all tdb's */
@ -941,7 +931,10 @@ _PUBLIC_ int tdb_reopen_all(int parent_longlived)
struct tdb_context *tdb;
for (tdb=tdbs; tdb; tdb = tdb->next) {
bool active_lock = (tdb->flags & TDB_CLEAR_IF_FIRST);
bool active_lock;
active_lock =
(tdb->flags & (TDB_CLEAR_IF_FIRST|TDB_MUTEX_LOCKING));
/*
* If the parent is longlived (ie. a

7
lib/tdb/test/run-mutex-openflags2.c
View File

@ -112,13 +112,6 @@ int main(int argc, char *argv[])
data.dsize = strlen("world");
data.dptr = discard_const_p(uint8_t, "world");
tdb = tdb_open_ex("mutex-openflags2.tdb", 0,
TDB_INCOMPATIBLE_HASH|
TDB_MUTEX_LOCKING,
O_RDWR|O_CREAT, 0755, &nolog_ctx, NULL);
ok((tdb == NULL) && (errno == EINVAL), "TDB_MUTEX_LOCKING without "
"TDB_CLEAR_IF_FIRST should fail with EINVAL - %d", errno);
if (!runtime_support) {
tdb = tdb_open_ex("mutex-openflags2.tdb", 0,
TDB_CLEAR_IF_FIRST|