From bbd2be36910728f485ac78ea36e0f4f5a38e691e Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 24 May 2011 11:59:18 -0400 Subject: [PATCH] jbd2: Add function jbd2_trans_will_send_data_barrier() Provide a function which returns whether a transaction with given tid will send a flush to the filesystem device. The function will be used by ext4 to detect whether fsync needs to send a separate flush or not. Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o" --- fs/jbd2/commit.c | 10 +++++++++- fs/jbd2/journal.c | 41 +++++++++++++++++++++++++++++++++++++++++ include/linux/jbd2.h | 4 +++- 3 files changed, 53 insertions(+), 2 deletions(-) diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 2d5095ecc25..5b506e53c70 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -677,6 +677,10 @@ start_journal_io: err = 0; } + write_lock(&journal->j_state_lock); + J_ASSERT(commit_transaction->t_state == T_COMMIT); + commit_transaction->t_state = T_COMMIT_DFLUSH; + write_unlock(&journal->j_state_lock); /* * If the journal is not located on the file system device, * then we must flush the file system device before we issue @@ -804,6 +808,10 @@ 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_DFLUSH); + commit_transaction->t_state = T_COMMIT_JFLUSH; + write_unlock(&journal->j_state_lock); if (!JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { @@ -959,7 +967,7 @@ 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_JFLUSH); 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 cd2d341f602..9a782699030 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -588,6 +588,47 @@ 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; + + if (!(journal->j_flags & JBD2_BARRIER)) + return 0; + read_lock(&journal->j_state_lock); + /* Transaction already committed? */ + if (tid_geq(journal->j_commit_sequence, tid)) + goto out; + commit_trans = journal->j_committing_transaction; + if (!commit_trans || commit_trans->t_tid != tid) { + ret = 1; + goto out; + } + /* + * Transaction is being committed and we already proceeded to + * submitting a flush to fs partition? + */ + if (journal->j_fs_dev != journal->j_dev) { + if (!commit_trans->t_need_data_flush || + commit_trans->t_state >= T_COMMIT_DFLUSH) + goto out; + } else { + if (commit_trans->t_state >= T_COMMIT_JFLUSH) + 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 4d57955061f..4ecb7b16b27 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -529,9 +529,10 @@ struct transaction_s enum { T_RUNNING, T_LOCKED, - T_RUNDOWN, T_FLUSH, T_COMMIT, + T_COMMIT_DFLUSH, + T_COMMIT_JFLUSH, T_FINISHED } t_state; @@ -1230,6 +1231,7 @@ 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 *); -- 2.11.4.GIT