ext4, jbd2: Add barriers for file systems with exernal journals

[safe/jmp/linux-2.6] / fs / ext4 / fsync.c

diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 0b22497..98bd140 100644 (file)
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -88,9 +88,21 @@ int ext4_sync_file(struct file *file, struct dentry *dentry, int datasync)
                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))
+       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);
                jbd2_log_wait_commit(journal, commit_tid);
-       else if (journal->j_flags & JBD2_BARRIER)
+       } else if (journal->j_flags & JBD2_BARRIER)
                blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
        return ret;
 }