jbd: Provide function to check whether transaction will issue data barrier
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 ext3 to detect whether fsync needs to send a separate barrier or not.
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index ecb44c9..28a9dda 100644
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -786,6 +786,12 @@
jbd_debug(3, "JBD: commit phase 6\n");
+ /* All metadata is written, now write commit record and do cleanup */
+ spin_lock(&journal->j_state_lock);
+ J_ASSERT(commit_transaction->t_state == T_COMMIT);
+ commit_transaction->t_state = T_COMMIT_RECORD;
+ spin_unlock(&journal->j_state_lock);
+
if (journal_write_commit_record(journal, commit_transaction))
err = -EIO;
@@ -923,7 +929,7 @@
jbd_debug(3, "JBD: commit phase 8\n");
- J_ASSERT(commit_transaction->t_state == T_COMMIT);
+ J_ASSERT(commit_transaction->t_state == T_COMMIT_RECORD);
commit_transaction->t_state = T_FINISHED;
J_ASSERT(commit_transaction == journal->j_committing_transaction);
diff --git a/fs/jbd/journal.c b/fs/jbd/journal.c
index bd224ee..99c71940 100644
--- a/fs/jbd/journal.c
+++ b/fs/jbd/journal.c
@@ -565,6 +565,38 @@
}
/*
+ * 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 journal_trans_will_send_data_barrier(journal_t *journal, tid_t tid)
+{
+ int ret = 0;
+ transaction_t *commit_trans;
+
+ if (!(journal->j_flags & JFS_BARRIER))
+ return 0;
+ spin_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
+ * writing commit record?
+ */
+ 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:
+ spin_unlock(&journal->j_state_lock);
+ return ret;
+}
+EXPORT_SYMBOL(journal_commit_will_send_barrier);
+
+/*
* Log buffer allocation routines:
*/
@@ -1157,6 +1189,7 @@
{
int err = 0;
+
/* Wait for the commit thread to wake up and die. */
journal_kill_thread(journal);
diff --git a/include/linux/jbd.h b/include/linux/jbd.h
index 516a2a2..e069650 100644
--- a/include/linux/jbd.h
+++ b/include/linux/jbd.h
@@ -427,9 +427,9 @@
enum {
T_RUNNING,
T_LOCKED,
- T_RUNDOWN,
T_FLUSH,
T_COMMIT,
+ T_COMMIT_RECORD,
T_FINISHED
} t_state;
@@ -991,6 +991,7 @@
int journal_force_commit_nested(journal_t *journal);
int log_wait_commit(journal_t *journal, tid_t tid);
int log_do_checkpoint(journal_t *journal);
+int journal_trans_will_send_data_barrier(journal_t *journal, tid_t tid);
void __log_wait_for_space(journal_t *journal);
extern void __journal_drop_transaction(journal_t *, transaction_t *);