From: Jan Kara Subject: [PATCH 1/2] jbd2: Provide function to check whether transaction will issue data barrier Date: Tue, 17 May 2011 12:28:14 +0200 Message-ID: <1305628095-27843-2-git-send-email-jack@suse.cz> References: <1305628095-27843-1-git-send-email-jack@suse.cz> Cc: Edward Goggin , linux-ext4@vger.kernel.org, Jan Kara To: tytso@mit.edu Return-path: Received: from cantor2.suse.de ([195.135.220.15]:39518 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752836Ab1EQK2s (ORCPT ); Tue, 17 May 2011 06:28:48 -0400 In-Reply-To: <1305628095-27843-1-git-send-email-jack@suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: Provide a function which returns whether a transaction with given tid will send a barrier to the filesystem device. The function will be used by ext4 to detect whether fsync needs to send a separate barrier or not. Signed-off-by: Jan Kara --- fs/jbd2/commit.c | 6 +++++- fs/jbd2/journal.c | 37 +++++++++++++++++++++++++++++++++++++ include/linux/jbd2.h | 3 ++- 3 files changed, 44 insertions(+), 2 deletions(-) diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 6e28000..e7812ed 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -800,6 +800,10 @@ wait_for_iobuf: jbd2_journal_abort(journal, err); jbd_debug(3, "JBD: commit phase 5\n"); + write_lock(&journal->j_state_lock); + J_ASSERT(commit_transaction->t_state == T_COMMIT); + commit_transaction->t_state = T_COMMIT_RECORD; + write_unlock(&journal->j_state_lock); if (!JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { @@ -955,7 +959,7 @@ restart_loop: jbd_debug(3, "JBD: commit phase 7\n"); - J_ASSERT(commit_transaction->t_state == T_COMMIT); + J_ASSERT(commit_transaction->t_state == T_COMMIT_RECORD); commit_transaction->t_start = jiffies; stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging, diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index e0ec3db..dbafbc5 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -577,6 +577,43 @@ int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid) } /* + * Return 1 if a given transaction has not yet sent barrier request + * connected with a transaction commit. If 0 is returned, transaction + * may or may not have sent the barrier. Used to avoid sending barrier + * twice in common cases. + */ +int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid) +{ + int ret = 0; + transaction_t *commit_trans; + + /* + * For external journal sending data barrier is more complex so just + * admit we don't know... + */ + if (!(journal->j_flags & JBD2_BARRIER) || + journal->j_fs_dev != journal->j_dev) + return 0; + read_lock(&journal->j_state_lock); + /* Transaction already committed? */ + if (tid_geq(journal->j_commit_sequence, tid)) + goto out; + /* + * Transaction is being committed and we already proceeded to + * submitting barrier? + */ + commit_trans = journal->j_committing_transaction; + if (commit_trans && commit_trans->t_tid == tid && + commit_trans->t_state >= T_COMMIT_RECORD) + goto out; + ret = 1; +out: + read_unlock(&journal->j_state_lock); + return ret; +} +EXPORT_SYMBOL(jbd2_trans_will_send_data_barrier); + +/* * Wait for a specified commit to complete. * The caller may not hold the journal lock. */ diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index a32dcae..fea6d6f 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -529,9 +529,9 @@ struct transaction_s enum { T_RUNNING, T_LOCKED, - T_RUNDOWN, T_FLUSH, T_COMMIT, + T_COMMIT_RECORD, T_FINISHED } t_state; @@ -1228,6 +1228,7 @@ int jbd2_journal_start_commit(journal_t *journal, tid_t *tid); int jbd2_journal_force_commit_nested(journal_t *journal); int jbd2_log_wait_commit(journal_t *journal, tid_t tid); int jbd2_log_do_checkpoint(journal_t *journal); +int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid); void __jbd2_log_wait_for_space(journal_t *journal); extern void __jbd2_journal_drop_transaction(journal_t *, transaction_t *); -- 1.7.1