X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb%2Ftransaction.c;h=9cbbcc9087fe1d441c4a829b7c121d560d57146a;hp=c5580f205d39c074fbbe52f9f5545659638112c3;hb=d665ff828977d76f8ec6ed53e6aab2e6fa124675;hpb=176844c84ff5ae6a5f146c5d1b7a3927bd781739 diff --git a/ccan/tdb/transaction.c b/ccan/tdb/transaction.c index c5580f20..9cbbcc90 100644 --- 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; @@ -411,30 +408,12 @@ static int transaction_expand_file(struct tdb_context *tdb, tdb_off_t size, return 0; } -/* - brlock during a transaction - ignore them -*/ -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; -} - static const struct tdb_methods transaction_methods = { transaction_read, transaction_write, transaction_next_hash_chain, transaction_oob, transaction_expand_file, - transaction_brlock, - transaction_brunlock }; /* @@ -466,8 +445,8 @@ static int transaction_sync(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t return 0; } -/* ltype is F_WRLCK after prepare. */ -int _tdb_transaction_cancel(struct tdb_context *tdb, int ltype) + +static int _tdb_transaction_cancel(struct tdb_context *tdb) { int i, ret = 0; @@ -494,43 +473,22 @@ int _tdb_transaction_cancel(struct tdb_context *tdb, int ltype) 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 */ - 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; } } - 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;inum_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; - tdb_brunlock(tdb, ltype, FREELIST_TOP, 0); tdb_transaction_unlock(tdb, F_WRLCK); SAFE_FREE(tdb->transaction->hash_heads); SAFE_FREE(tdb->transaction); @@ -564,7 +522,7 @@ 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 */ @@ -603,10 +561,9 @@ 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, F_RDLCK, FREELIST_TOP, 0, TDB_LOCK_WAIT) == -1) { + if (tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, true) == -1) { TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_start: failed to get hash locks\n")); - tdb->ecode = TDB_ERR_LOCK; - goto fail; + goto fail_allrecord_lock; } /* setup a copy of the hash table heads so the hash scan in @@ -639,7 +596,8 @@ int tdb_transaction_start(struct tdb_context *tdb) return 0; fail: - tdb_brunlock(tdb, F_RDLCK, FREELIST_TOP, 0); + tdb_allrecord_unlock(tdb, F_RDLCK, false); +fail_allrecord_lock: tdb_transaction_unlock(tdb, F_WRLCK); SAFE_FREE(tdb->transaction->blocks); SAFE_FREE(tdb->transaction->hash_heads); @@ -653,11 +611,8 @@ fail: */ int tdb_transaction_cancel(struct tdb_context *tdb) { - int ltype = F_RDLCK; tdb_trace(tdb, "tdb_transaction_cancel"); - if (tdb->transaction && tdb->transaction->prepared) - ltype = F_WRLCK; - return _tdb_transaction_cancel(tdb, ltype); + return _tdb_transaction_cancel(tdb); } /* @@ -707,10 +662,16 @@ static int tdb_recovery_allocate(struct tdb_context *tdb, rec.rec_len = 0; - if (recovery_head != 0 && - methods->tdb_read(tdb, recovery_head, &rec, sizeof(rec), DOCONV()) == -1) { - TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to read recovery record\n")); - return -1; + if (recovery_head != 0) { + if (methods->tdb_read(tdb, recovery_head, &rec, sizeof(rec), DOCONV()) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to read recovery record\n")); + return -1; + } + /* ignore invalid recovery regions: can happen in crash */ + if (rec.magic != TDB_RECOVERY_MAGIC && + rec.magic != TDB_RECOVERY_INVALID_MAGIC) { + recovery_head = 0; + } } *recovery_size = tdb_recovery_size(tdb); @@ -805,7 +766,7 @@ static int transaction_setup_recovery(struct tdb_context *tdb, 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; @@ -917,14 +878,14 @@ static int _tdb_transaction_prepare_commit(struct tdb_context *tdb) if (tdb->transaction->prepared) { tdb->ecode = TDB_ERR_EINVAL; - _tdb_transaction_cancel(tdb, F_WRLCK); + _tdb_transaction_cancel(tdb); 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, F_RDLCK); + _tdb_transaction_cancel(tdb); TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_prepare_commit: transaction error pending\n")); return -1; } @@ -944,37 +905,33 @@ 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); + _tdb_transaction_cancel(tdb); return -1; } /* upgrade the main transaction lock region to a write lock */ - if (tdb_brlock_upgrade(tdb, FREELIST_TOP, 0) == -1) { + if (tdb_allrecord_upgrade(tdb) == -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, F_RDLCK); + _tdb_transaction_cancel(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; - _tdb_transaction_cancel(tdb, F_WRLCK); + 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); 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) { TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_prepare_commit: failed to setup recovery data\n")); - _tdb_transaction_cancel(tdb, F_WRLCK); + _tdb_transaction_cancel(tdb); return -1; } } @@ -988,14 +945,14 @@ 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_transaction_cancel(tdb, F_WRLCK); + _tdb_transaction_cancel(tdb); return -1; } tdb->map_size = tdb->transaction->old_map_size; 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; } @@ -1040,7 +997,7 @@ int tdb_transaction_commit(struct tdb_context *tdb) /* check for a null transaction */ if (tdb->transaction->blocks == NULL) { - _tdb_transaction_cancel(tdb, F_RDLCK); + _tdb_transaction_cancel(tdb); return 0; } @@ -1076,7 +1033,7 @@ int tdb_transaction_commit(struct tdb_context *tdb) tdb->methods = methods; tdb_transaction_recover(tdb); - _tdb_transaction_cancel(tdb, F_WRLCK); + _tdb_transaction_cancel(tdb); TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_commit: write failed\n")); return -1; @@ -1111,7 +1068,7 @@ int tdb_transaction_commit(struct tdb_context *tdb) /* use a transaction cancel to free memory and remove the transaction locks */ - _tdb_transaction_cancel(tdb, F_WRLCK); + _tdb_transaction_cancel(tdb); if (need_repack) { return tdb_repack(tdb); @@ -1123,7 +1080,7 @@ 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) @@ -1225,16 +1182,6 @@ int tdb_transaction_recover(struct tdb_context *tdb) return -1; } - /* reduce the file size to the old size */ - tdb_munmap(tdb); - if (ftruncate(tdb->fd, recovery_eof) != 0) { - TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to reduce to recovery size\n")); - tdb->ecode = TDB_ERR_IO; - return -1; - } - tdb->map_size = recovery_eof; - tdb_mmap(tdb); - if (transaction_sync(tdb, 0, recovery_eof) == -1) { TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_transaction_recover: failed to sync2 recovery\n")); tdb->ecode = TDB_ERR_IO;