From b8a6176c214cf9aa2679131ed7e4515cddaadc33 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Wed, 1 Nov 2017 16:36:45 +0100 Subject: ext4: Support for synchronous DAX faults We return IOMAP_F_DIRTY flag from ext4_iomap_begin() when asked to prepare blocks for writing and the inode has some uncommitted metadata changes. In the fault handler ext4_dax_fault() we then detect this case (through VM_FAULT_NEEDDSYNC return value) and call helper dax_finish_sync_fault() to flush metadata changes and insert page table entry. Note that this will also dirty corresponding radix tree entry which is what we want - fsync(2) will still provide data integrity guarantees for applications not using userspace flushing. And applications using userspace flushing can avoid calling fsync(2) and thus avoid the performance overhead. Reviewed-by: Ross Zwisler Signed-off-by: Jan Kara Signed-off-by: Dan Williams --- fs/jbd2/journal.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'fs/jbd2') diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 7d5ef3b..fa8cde4 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -738,6 +738,23 @@ int jbd2_log_wait_commit(journal_t *journal, tid_t tid) return err; } +/* Return 1 when transaction with given tid has already committed. */ +int jbd2_transaction_committed(journal_t *journal, tid_t tid) +{ + int ret = 1; + + read_lock(&journal->j_state_lock); + if (journal->j_running_transaction && + journal->j_running_transaction->t_tid == tid) + ret = 0; + if (journal->j_committing_transaction && + journal->j_committing_transaction->t_tid == tid) + ret = 0; + read_unlock(&journal->j_state_lock); + return ret; +} +EXPORT_SYMBOL(jbd2_transaction_committed); + /* * When this function returns the transaction corresponding to tid * will be completed. If the transaction has currently running, start -- cgit v1.1