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 <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 2d5095e..5b506e5 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -677,6 +677,10 @@
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 @@
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 @@
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 cd2d341..9a78269 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -588,6 +588,47 @@
}
/*
+ * 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.
*/
