tdb: use tdb_nest_lock() for open lock.

[ccan] / ccan / tdb / transaction.c

diff --git a/ccan/tdb/transaction.c b/ccan/tdb/transaction.c
index 261428fd9c9e5d0b902266ff3b91f9a24a37b898..ded3fa836fc721a07932c54a6f741b89c8329066 100644 (file)
--- a/ccan/tdb/transaction.c
+++ b/ccan/tdb/transaction.c
@@ -76,7 +76,7 @@
     to reduce this to 3 or even 2 with some more work.
 
   - check for a valid recovery record on open of the tdb, while the
-    global lock is held. Automatically recover from the transaction
+    open lock is held. Automatically recover from the transaction
     recovery area if needed, then continue with the open as
     usual. This allows for smooth crash recovery with no administrator
     intervention.
@@ -135,9 +135,6 @@ struct tdb_transaction {
        bool prepared;
        tdb_off_t magic_offset;
 
-       /* set when the GLOBAL_LOCK has been taken */
-       bool global_lock_taken;
-
        /* old file size before transaction */
        tdb_len_t old_map_size;
 
@@ -418,6 +415,9 @@ static int transaction_brlock(struct tdb_context *tdb,
                              int rw_type, tdb_off_t offset, size_t len,
                              enum tdb_lock_flags flags)
 {
+       /* FIXME: We actually grab the open lock during a transaction. */
+       if (offset == OPEN_LOCK)
+               return tdb_brlock(tdb, rw_type, offset, len, flags);
        return 0;
 }
 
@@ -504,28 +504,8 @@ int _tdb_transaction_cancel(struct tdb_context *tdb, int ltype)
                }
        }
 
-       if (tdb->transaction->global_lock_taken) {
-               tdb_brunlock(tdb, F_WRLCK, GLOBAL_LOCK, 1);
-               tdb->transaction->global_lock_taken = false;
-       }
-
-       /* remove any global lock created during the transaction */
-       if (tdb->global_lock.count != 0) {
-               tdb_brunlock(tdb, tdb->global_lock.ltype,
-                            FREELIST_TOP, 4*tdb->header.hash_size);
-               tdb->global_lock.count = 0;
-       }
-
-       /* remove any locks created during the transaction */
-       if (tdb->num_locks != 0) {
-               for (i=0;i<tdb->num_lockrecs;i++) {
-                       tdb_brunlock(tdb, tdb->lockrecs[i].ltype,
-                                    FREELIST_TOP+4*tdb->lockrecs[i].list, 1);
-               }
-               tdb->num_locks = 0;
-               tdb->num_lockrecs = 0;
-               SAFE_FREE(tdb->lockrecs);
-       }
+       /* This also removes the OPEN_LOCK, if we have it. */
+       tdb_release_extra_locks(tdb);
 
        /* restore the normal io methods */
        tdb->methods = tdb->transaction->io_methods;
@@ -564,7 +544,7 @@ int tdb_transaction_start(struct tdb_context *tdb)
                return 0;
        }
 
-       if (tdb->num_locks != 0 || tdb->global_lock.count) {
+       if (tdb_have_extra_locks(tdb)) {
                /* the caller must not have any locks when starting a
                   transaction as otherwise we'll be screwed by lack
                   of nested locks in posix */
@@ -944,7 +924,7 @@ static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
        
        /* if there are any locks pending then the caller has not
           nested their locks properly, so fail the transaction */
-       if (tdb->num_locks || tdb->global_lock.count) {
+       if (tdb_have_extra_locks(tdb)) {
                tdb->ecode = TDB_ERR_LOCK;
                TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: locks pending on commit\n"));
                _tdb_transaction_cancel(tdb, F_RDLCK);
@@ -959,17 +939,14 @@ static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
                return -1;
        }
 
-       /* get the global lock - this prevents new users attaching to the database
+       /* get the open lock - this prevents new users attaching to the database
           during the commit */
-       if (tdb_brlock(tdb, F_WRLCK, GLOBAL_LOCK, 1, TDB_LOCK_WAIT) == -1) {
-               TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to get global lock\n"));
-               tdb->ecode = TDB_ERR_LOCK;
+       if (tdb_nest_lock(tdb, OPEN_LOCK, F_WRLCK, TDB_LOCK_WAIT) == -1) {
+               TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to get open lock\n"));
                _tdb_transaction_cancel(tdb, F_WRLCK);
                return -1;
        }
 
-       tdb->transaction->global_lock_taken = true;
-
        if (!(tdb->flags & TDB_NOSYNC)) {
                /* write the recovery data to the end of the file */
                if (transaction_setup_recovery(tdb, &tdb->transaction->magic_offset) == -1) {
@@ -995,7 +972,7 @@ static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
                methods->tdb_oob(tdb, tdb->map_size + 1, 1);
        }
 
-       /* Keep the global lock until the actual commit */
+       /* Keep the open lock until the actual commit */
 
        return 0;
 }
@@ -1123,7 +1100,7 @@ int tdb_transaction_commit(struct tdb_context *tdb)
 
 /*
   recover from an aborted transaction. Must be called with exclusive
-  database write access already established (including the global
+  database write access already established (including the open
   lock to prevent new processes attaching)
 */
 int tdb_transaction_recover(struct tdb_context *tdb)