On 16.05.2011 12:37, Daniel Shahaf wrote:
Stefan Fuhrmann wrote on Sun, May 15, 2011 at 18:17:22 +0200:
On 14.05.2011 03:54, Daniel Shahaf wrote:
stef...@apache.org wrote on Sun, Apr 17, 2011 at 14:48:34 -0000:
Author: stefan2
Date: Sun Apr 17 14:48:33 2011
New Revision: 1094150
URL: http://svn.apache.org/viewvc?rev=1094150&view=rev
Log:
Support concurrent transactions on FSFS: reset txn-local caches upon
closing the txn (i.e. don't wait until pool cleanup) and support concurrency
by simply disabling these caches permanently for the respective session
once a concurrency has been detected.
+ struct txn_cleanup_baton_t *baton;
+
+ baton = apr_palloc(pool, sizeof(*baton));
+ baton->txn_cache = *cache;
+ baton->to_reset = cache;
+
+ apr_pool_cleanup_register(pool,
+ baton,
+ remove_txn_cache,
+ apr_pool_cleanup_null);
+ }
+
+ return SVN_NO_ERROR;
+}
+
svn_error_t *
svn_fs_fs__initialize_txn_caches(svn_fs_t *fs,
const char *txn_id,
@@ -361,9 +395,15 @@ svn_fs_fs__initialize_txn_caches(svn_fs_
":", svn_uuid_generate(pool), ":",
(char *)NULL);
- /* There must be no concurrent transactions in progress for the same
- FSFS access / session object. Maybe, you forgot to clean POOL. */
- SVN_ERR_ASSERT(ffd->txn_dir_cache == NULL);
+ /* We don't support caching for concurrent transactions in the SAME
+ * FSFS session. Maybe, you forgot to clean POOL. */
+ if (ffd->txn_dir_cache != NULL || ffd->concurrent_transactions)
+ {
+ ffd->txn_dir_cache = NULL;
+ ffd->concurrent_transactions = TRUE;
+
+ return SVN_NO_ERROR;
+ }
Why is this safe?
Is it because svn_fs_fs__initialize_txn_caches() is called from all the
relevant codepaths? (presumably the relevant codepaths are those that
create txns)
Correct. The assumption that is being made here is that either
* transactions won't use txn-local caches without previously
calling svn_fs_fs__initialize_txn_caches, or
* no two transactions are being run concurrently within the
same FSFS session.
Okay. There is only one code path that initializes txn's, so I'm not
too worried about documenting this centrally...
But: the call in make_txn_root() to svn_fs_fs__initialize_txn_caches()
is missing an SVN_ERR() wrapper. Could you look into these please?
Done in r1104332.
-- Stefan^2.
