--- fs/ext4/fsync.c

+++ fs/ext4/fsync.c

@@ -35,6 +35,29 @@

#include <trace/events/ext4.h>

/*

+ * If we're not journaling and this is a just-created file, we have to

+ * sync our parent directory (if it was freshly created) since

+ * otherwise it will only be written by writeback, leaving a huge

+ * window during which a crash may lose the file. This may apply for

+ * the parent directory's parent as well, and so on recursively, if

+ * they are also freshly created.

+ */

+static void ext4_sync_parent(struct inode *inode)

+{

+ struct dentry *dentry = NULL;

+

+ while (inode && ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) {

+ ext4_clear_inode_state(inode, EXT4_STATE_NEWENTRY);

+ dentry = list_entry(inode->i_dentry.next,

+ struct dentry, d_alias);

+ if (!dentry || !dentry->d_parent || !dentry->d_parent->d_inode)

+ break;

+ inode = dentry->d_parent->d_inode;

+ sync_mapping_buffers(inode->i_mapping);

+ }

+}

+

+/*

* akpm: A new design for ext4_sync_file().

*

* This is only called from sys_fsync(), sys_fdatasync() and sys_msync().

@@ -67,8 +90,12 @@ int ext4_sync_file(struct file *file, st

if (ret < 0)

return ret;

- if (!journal)

- return simple_fsync(file, dentry, datasync);

+ if (!journal) {

+ ret = simple_fsync(file, dentry, datasync);

+ if (!ret && !list_empty(&inode->i_dentry))

+ ext4_sync_parent(inode);

+ return ret;

+ }

/*

* data=writeback,ordered:

@@ -88,9 +115,21 @@ int ext4_sync_file(struct file *file, st

return ext4_force_commit(inode->i_sb);

commit_tid = datasync ? ei->i_datasync_tid : ei->i_sync_tid;

- if (jbd2_log_start_commit(journal, commit_tid))

- jbd2_log_wait_commit(journal, commit_tid);

- else if (journal->j_flags & JBD2_BARRIER)

+ if (jbd2_log_start_commit(journal, commit_tid)) {

+ /*

+ * When the journal is on a different device than the

+ * fs data disk, we need to issue the barrier in

+ * writeback mode. (In ordered mode, the jbd2 layer

+ * will take care of issuing the barrier. In

+ * data=journal, all of the data blocks are written to

+ * the journal device.)

+ */

+ if (ext4_should_writeback_data(inode) &&

+ (journal->j_fs_dev != journal->j_dev) &&

+ (journal->j_flags & JBD2_BARRIER))

+ blkdev_issue_flush(inode->i_sb->s_bdev, NULL);

+ ret = jbd2_log_wait_commit(journal, commit_tid);

+ } else if (journal->j_flags & JBD2_BARRIER)

blkdev_issue_flush(inode->i_sb->s_bdev, NULL);

return ret;

}