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 c5580f205d39c074fbbe52f9f5545659638112c3..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
     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.
     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;
 
        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;
 
        /* 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)
 {
                              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;
 }
 
        return 0;
 }
 


@@ -494,38 +494,18 @@ int _tdb_transaction_cancel(struct tdb_context *tdb, int ltype)
 
        if (tdb->transaction->magic_offset) {
                const struct tdb_methods *methods = tdb->transaction->io_methods;
 
        if (tdb->transaction->magic_offset) {
                const struct tdb_methods *methods = tdb->transaction->io_methods;

-               uint32_t zero = 0;
+               uint32_t invalid = TDB_RECOVERY_INVALID_MAGIC;

 
                /* remove the recovery marker */
 
                /* remove the recovery marker */

-               if (methods->tdb_write(tdb, tdb->transaction->magic_offset, &zero, 4) == -1 ||
+               if (methods->tdb_write(tdb, tdb->transaction->magic_offset, &invalid, 4) == -1 ||

                transaction_sync(tdb, tdb->transaction->magic_offset, 4) == -1) {
                        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_cancel: failed to remove recovery magic\n"));
                        ret = -1;
                }
        }
 
                transaction_sync(tdb, tdb->transaction->magic_offset, 4) == -1) {
                        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_cancel: failed to remove recovery magic\n"));
                        ret = -1;
                }
        }
 

-       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;
 
        /* 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;
        }
 
                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 */
                /* the caller must not have any locks when starting a
                   transaction as otherwise we'll be screwed by lack
                   of nested locks in posix */


@@ -805,7 +785,7 @@ static int transaction_setup_recovery(struct tdb_context *tdb,
        rec = (struct tdb_record *)data;
        memset(rec, 0, sizeof(*rec));
 
        rec = (struct tdb_record *)data;
        memset(rec, 0, sizeof(*rec));
 

-       rec->magic    = 0;
+       rec->magic    = TDB_RECOVERY_INVALID_MAGIC;

        rec->data_len = recovery_size;
        rec->rec_len  = recovery_max_size;
        rec->key_len  = old_map_size;
        rec->data_len = recovery_size;
        rec->rec_len  = recovery_max_size;
        rec->key_len  = old_map_size;


@@ -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 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);
                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;
        }
 
                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 */
           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_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) {
        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);
        }
 
                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;
 }
 
        return 0;
 }


@@ -1123,7 +1100,7 @@ int tdb_transaction_commit(struct tdb_context *tdb)
 
 /*
   recover from an aborted transaction. Must be called with exclusive
 
 /*
   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)
   lock to prevent new processes attaching)
 */
 int tdb_transaction_recover(struct tdb_context *tdb)