tdb: locking cleanup

[ccan] / ccan / tdb / transaction.c

diff --git a/ccan/tdb/transaction.c b/ccan/tdb/transaction.c
index 7e8ac34dd5bc7e93a9a20cd9ac7e127716d3e504..c2e4748a8e7c668acb9c568660a59ab9c2f4cff6 100644 (file)
--- a/ccan/tdb/transaction.c
+++ b/ccan/tdb/transaction.c
@@ -411,8 +411,15 @@ static int transaction_expand_file(struct tdb_context *tdb, tdb_off_t size,
 /*
   brlock during a transaction - ignore them
 */
-static int transaction_brlock(struct tdb_context *tdb, tdb_off_t offset, 
-                             int rw_type, int lck_type, int probe, size_t len)
+static int transaction_brlock(struct tdb_context *tdb,
+                             int rw_type, tdb_off_t offset, size_t len,
+                             enum tdb_lock_flags flags)
+{
+       return 0;
+}
+
+static int transaction_brunlock(struct tdb_context *tdb,
+                               int rw_type, tdb_off_t offset, size_t len)
 {
        return 0;
 }
@@ -423,7 +430,8 @@ static const struct tdb_methods transaction_methods = {
        transaction_next_hash_chain,
        transaction_oob,
        transaction_expand_file,
-       transaction_brlock
+       transaction_brlock,
+       transaction_brunlock
 };
 
 /*
@@ -455,7 +463,8 @@ static int transaction_sync(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t
        return 0;
 }
 
-int _tdb_transaction_cancel(struct tdb_context *tdb)
+/* ltype is F_WRLCK after prepare. */
+int _tdb_transaction_cancel(struct tdb_context *tdb, int ltype)
 {
        int i, ret = 0;
 
@@ -494,15 +503,16 @@ int _tdb_transaction_cancel(struct tdb_context *tdb)
 
        /* remove any global lock created during the transaction */
        if (tdb->global_lock.count != 0) {
-               tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, 0, 4*tdb->header.hash_size);
+               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_brlock(tdb,FREELIST_TOP+4*tdb->lockrecs[i].list,
-                                  F_UNLCK,F_SETLKW, 0, 1);
+                       tdb_brunlock(tdb, tdb->lockrecs[i].ltype,
+                                    FREELIST_TOP+4*tdb->lockrecs[i].list, 1);
                }
                tdb->num_locks = 0;
                tdb->num_lockrecs = 0;
@@ -512,8 +522,8 @@ int _tdb_transaction_cancel(struct tdb_context *tdb)
        /* restore the normal io methods */
        tdb->methods = tdb->transaction->io_methods;
 
-       tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, 0, 0);
-       tdb_transaction_unlock(tdb);
+       tdb_brunlock(tdb, ltype, FREELIST_TOP, 0);
+       tdb_transaction_unlock(tdb, F_WRLCK);
        SAFE_FREE(tdb->transaction->hash_heads);
        SAFE_FREE(tdb->transaction);
        
@@ -585,7 +595,7 @@ int tdb_transaction_start(struct tdb_context *tdb)
        
        /* get a read lock from the freelist to the end of file. This
           is upgraded to a write lock during the commit */
-       if (tdb_brlock(tdb, FREELIST_TOP, F_RDLCK, F_SETLKW, 0, 0) == -1) {
+       if (tdb_brlock(tdb, F_RDLCK, FREELIST_TOP, 0, TDB_LOCK_WAIT) == -1) {
                TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_start: failed to get hash locks\n"));
                tdb->ecode = TDB_ERR_LOCK;
                goto fail;
@@ -621,8 +631,8 @@ int tdb_transaction_start(struct tdb_context *tdb)
        return 0;
        
 fail:
-       tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, 0, 0);
-       tdb_transaction_unlock(tdb);
+       tdb_brunlock(tdb, F_RDLCK, FREELIST_TOP, 0);
+       tdb_transaction_unlock(tdb, F_WRLCK);
        SAFE_FREE(tdb->transaction->blocks);
        SAFE_FREE(tdb->transaction->hash_heads);
        SAFE_FREE(tdb->transaction);
@@ -634,9 +644,12 @@ fail:
   cancel the current transaction
 */
 int tdb_transaction_cancel(struct tdb_context *tdb)
-{      
+{
+       int ltype = F_RDLCK;
        tdb_trace(tdb, "tdb_transaction_cancel");
-       return _tdb_transaction_cancel(tdb);
+       if (tdb->transaction && tdb->transaction->prepared)
+               ltype = F_WRLCK;
+       return _tdb_transaction_cancel(tdb, ltype);
 }
 
 /*
@@ -896,14 +909,14 @@ static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
 
        if (tdb->transaction->prepared) {
                tdb->ecode = TDB_ERR_EINVAL;
-               _tdb_transaction_cancel(tdb);
+               _tdb_transaction_cancel(tdb, F_WRLCK);
                TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: transaction already prepared\n"));
                return -1;
        }
 
        if (tdb->transaction->transaction_error) {
                tdb->ecode = TDB_ERR_IO;
-               _tdb_transaction_cancel(tdb);
+               _tdb_transaction_cancel(tdb, F_RDLCK);
                TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: transaction error pending\n"));
                return -1;
        }
@@ -931,7 +944,7 @@ static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
        if (tdb->num_locks || tdb->global_lock.count) {
                tdb->ecode = TDB_ERR_LOCK;
                TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: locks pending on commit\n"));
-               _tdb_transaction_cancel(tdb);
+               _tdb_transaction_cancel(tdb, F_RDLCK);
                return -1;
        }
 
@@ -939,16 +952,16 @@ static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
        if (tdb_brlock_upgrade(tdb, FREELIST_TOP, 0) == -1) {
                TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: failed to upgrade hash locks\n"));
                tdb->ecode = TDB_ERR_LOCK;
-               _tdb_transaction_cancel(tdb);
+               _tdb_transaction_cancel(tdb, F_RDLCK);
                return -1;
        }
 
        /* get the global lock - this prevents new users attaching to the database
           during the commit */
-       if (tdb_brlock(tdb, GLOBAL_LOCK, F_WRLCK, F_SETLKW, 0, 1) == -1) {
+       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;
-               _tdb_transaction_cancel(tdb);
+               _tdb_transaction_cancel(tdb, F_WRLCK);
                return -1;
        }
 
@@ -956,8 +969,8 @@ static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
                /* write the recovery data to the end of the file */
                if (transaction_setup_recovery(tdb, &tdb->transaction->magic_offset) == -1) {
                        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_prepare_commit: failed to setup recovery data\n"));
-                       tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
-                       _tdb_transaction_cancel(tdb);
+                       tdb_brunlock(tdb, F_WRLCK, GLOBAL_LOCK, 0);
+                       _tdb_transaction_cancel(tdb, F_WRLCK);
                        return -1;
                }
        }
@@ -971,8 +984,8 @@ static int _tdb_transaction_prepare_commit(struct tdb_context *tdb)
                                             tdb->transaction->old_map_size) == -1) {
                        tdb->ecode = TDB_ERR_IO;
                        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_prepare_commit: expansion failed\n"));
-                       tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
-                       _tdb_transaction_cancel(tdb);
+                       tdb_brunlock(tdb, F_WRLCK, GLOBAL_LOCK, 0);
+                       _tdb_transaction_cancel(tdb, F_WRLCK);
                        return -1;
                }
                tdb->map_size = tdb->transaction->old_map_size;
@@ -1030,7 +1043,7 @@ int tdb_transaction_commit(struct tdb_context *tdb)
 
        /* check for a null transaction */
        if (tdb->transaction->blocks == NULL) {
-               _tdb_transaction_cancel(tdb);
+               _tdb_transaction_cancel(tdb, F_RDLCK);
                return 0;
        }
 
@@ -1066,8 +1079,8 @@ int tdb_transaction_commit(struct tdb_context *tdb)
                        tdb->methods = methods;
                        tdb_transaction_recover(tdb); 
 
-                       _tdb_transaction_cancel(tdb);
-                       tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
+                       _tdb_transaction_cancel(tdb, F_WRLCK);
+                       tdb_brunlock(tdb, F_WRLCK, GLOBAL_LOCK, 0);
 
                        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_commit: write failed\n"));
                        return -1;
@@ -1083,7 +1096,7 @@ int tdb_transaction_commit(struct tdb_context *tdb)
                return -1;
        }
 
-       tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1);
+       tdb_brunlock(tdb, F_WRLCK, GLOBAL_LOCK, 1);
 
        /*
          TODO: maybe write to some dummy hdr field, or write to magic
@@ -1104,7 +1117,7 @@ int tdb_transaction_commit(struct tdb_context *tdb)
 
        /* use a transaction cancel to free memory and remove the
           transaction locks */
-       _tdb_transaction_cancel(tdb);
+       _tdb_transaction_cancel(tdb, F_WRLCK);
 
        if (need_repack) {
                return tdb_repack(tdb);