Reduce the locking coverage of the oft-used j_list_lock: the per-bh
jbd_lock_bh_state() gives us sufficient locking of buffer_head and
journal_head internals.
---
25-akpm/fs/jbd/transaction.c | 13 +++----------
1 files changed, 3 insertions(+), 10 deletions(-)
diff -puN fs/jbd/transaction.c~jbd-journal_dirty_metadata-locking-speedup fs/jbd/transaction.c
--- 25/fs/jbd/transaction.c~jbd-journal_dirty_metadata-locking-speedup Thu Apr 8 14:43:29 2004
+++ 25-akpm/fs/jbd/transaction.c Thu Apr 8 14:45:28 2004
@@ -1088,26 +1088,21 @@ int journal_dirty_metadata(handle_t *han
* I _think_ we're OK here with SMP barriers - a mistaken decision will
* result in this test being false, so we go in and take the locks.
*/
- if (jh->b_transaction == handle->h_transaction &&
- jh->b_jlist == BJ_Metadata) {
+ if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) {
JBUFFER_TRACE(jh, "fastpath");
J_ASSERT_JH(jh, jh->b_transaction ==
journal->j_running_transaction);
goto out_unlock_bh;
}
- spin_lock(&journal->j_list_lock);
set_buffer_jbddirty(bh);
- J_ASSERT_JH(jh, jh->b_transaction != NULL);
-
/*
* Metadata already on the current transaction list doesn't
* need to be filed. Metadata on another transaction's list must
* be committing, and will be refiled once the commit completes:
* leave it alone for now.
*/
-
if (jh->b_transaction != transaction) {
JBUFFER_TRACE(jh, "already on other transaction");
J_ASSERT_JH(jh, jh->b_transaction ==
@@ -1115,17 +1110,15 @@ int journal_dirty_metadata(handle_t *han
J_ASSERT_JH(jh, jh->b_next_transaction == transaction);
/* And this case is illegal: we can't reuse another
* transaction's data buffer, ever. */
- /* FIXME: writepage() should be journalled */
- goto out_unlock_list;
+ goto out_unlock_bh;
}
/* That test should have eliminated the following case: */
J_ASSERT_JH(jh, jh->b_frozen_data == 0);
JBUFFER_TRACE(jh, "file as BJ_Metadata");
+ spin_lock(&journal->j_list_lock);
__journal_file_buffer(jh, handle->h_transaction, BJ_Metadata);
-
-out_unlock_list:
spin_unlock(&journal->j_list_lock);
out_unlock_bh:
jbd_unlock_bh_state(bh);
_