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>
This commit is contained in:
Jan Kara 2011-05-24 11:59:18 -04:00 committed by Theodore Ts'o
parent 81be12c817
commit bbd2be3691
3 changed files with 53 additions and 2 deletions

View File

@ -677,6 +677,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
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 @@ void jbd2_journal_commit_transaction(journal_t *journal)
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 @@ void jbd2_journal_commit_transaction(journal_t *journal)
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,

View File

@ -587,6 +587,47 @@ int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
return ret;
}
/*
* 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.

View File

@ -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 *);