From: Jan Kara Subject: [PATCH 5/5] jbd2: Speedup jbd2_journal_dirty_metadata() Date: Thu, 2 Apr 2015 15:58:20 +0200 Message-ID: <1427983100-29889-6-git-send-email-jack@suse.cz> References: <1427983100-29889-1-git-send-email-jack@suse.cz> Cc: Ted Tso , Jan Kara To: linux-ext4@vger.kernel.org Return-path: Received: from cantor2.suse.de ([195.135.220.15]:51233 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753139AbbDBN6a (ORCPT ); Thu, 2 Apr 2015 09:58:30 -0400 In-Reply-To: <1427983100-29889-1-git-send-email-jack@suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: It is often the case that we mark buffer as having dirty metadata when the buffer is already in that state (frequent for bitmaps, inode table blocks, superblock). Thus it is unnecessary to contend on grabbing journal head reference and bh_state lock. Avoid that by checking whether any modification to the buffer is needed before grabbing any locks or references. Signed-off-by: Jan Kara --- fs/jbd2/transaction.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index a91f639af6c3..ad10ca8fb9ef 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -1290,8 +1290,6 @@ void jbd2_buffer_abort_trigger(struct journal_head *jh, triggers->t_abort(triggers, jh2bh(jh)); } - - /** * int jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata * @handle: transaction to add buffer to. @@ -1325,12 +1323,25 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) WARN_ON(!transaction); if (is_handle_aborted(handle)) return -EROFS; - journal = transaction->t_journal; - jh = jbd2_journal_grab_journal_head(bh); - if (!jh) { + if (!buffer_jbd(bh)) { ret = -EUCLEAN; goto out; } + /* + * We don't grab jh reference here since the buffer must be part + * of the running transaction. + */ + jh = bh2jh(bh); + J_ASSERT_JH(jh, jh->b_transaction == transaction || + jh->b_next_transaction == transaction); + if (jh->b_modified == 1) { + /* If it's in our transaction it must be in BJ_Metadata list */ + J_ASSERT_JH(jh, jh->b_transaction != transaction || + jh->b_jlist == BJ_Metadata); + goto out; + } + + journal = transaction->t_journal; jbd_debug(5, "journal_head %p\n", jh); JBUFFER_TRACE(jh, "entry"); @@ -1421,7 +1432,6 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) spin_unlock(&journal->j_list_lock); out_unlock_bh: jbd_unlock_bh_state(bh); - jbd2_journal_put_journal_head(jh); out: JBUFFER_TRACE(jh, "exit"); return ret; -- 2.1.4