diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 0b22497d92e1..98bd140aad01 100644
--- 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;
 }
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index ca0f5eb62b20..886849370950 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -22,6 +22,7 @@
 #include <linux/jbd2.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
+#include <linux/blkdev.h>
 #include <trace/events/jbd2.h>
 
 /*
@@ -515,6 +516,20 @@ int jbd2_cleanup_journal_tail(journal_t *journal)
 	journal->j_tail_sequence = first_tid;
 	journal->j_tail = blocknr;
 	spin_unlock(&journal->j_state_lock);
+
+	/*
+	 * If there is an external journal, we need to make sure that
+	 * any data blocks that were recently written out --- perhaps
+	 * by jbd2_log_do_checkpoint() --- are flushed out before we
+	 * drop the transactions from the external journal.  It's
+	 * unlikely this will be necessary, especially with a
+	 * appropriately sized journal, but we need this to guarantee
+	 * correctness.  Fortunately jbd2_cleanup_journal_tail()
+	 * doesn't get called all that often.
+	 */
+	if ((journal->j_fs_dev != journal->j_dev) &&
+	    (journal->j_flags & JBD2_BARRIER))
+		blkdev_issue_flush(journal->j_fs_dev, NULL);
 	if (!(journal->j_flags & JBD2_ABORT))
 		jbd2_journal_update_superblock(journal, 1);
 	return 0;
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 6a10238d2c63..1bc74b6f26d2 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -259,6 +259,7 @@ static int journal_submit_data_buffers(journal_t *journal,
 			ret = err;
 		spin_lock(&journal->j_list_lock);
 		J_ASSERT(jinode->i_transaction == commit_transaction);
+		commit_transaction->t_flushed_data_blocks = 1;
 		jinode->i_flags &= ~JI_COMMIT_RUNNING;
 		wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
 	}
@@ -708,8 +709,17 @@ start_journal_io:
 		}
 	}
 
-	/* Done it all: now write the commit record asynchronously. */
+	/* 
+	 * If the journal is not located on the file system device,
+	 * then we must flush the file system device before we issue
+	 * the commit record
+	 */
+	if (commit_transaction->t_flushed_data_blocks &&
+	    (journal->j_fs_dev != journal->j_dev) &&
+	    (journal->j_flags & JBD2_BARRIER))
+		blkdev_issue_flush(journal->j_fs_dev, NULL);
 
+	/* Done it all: now write the commit record asynchronously. */
 	if (JBD2_HAS_INCOMPAT_FEATURE(journal,
 				      JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
 		err = journal_submit_commit_record(journal, commit_transaction,
@@ -720,13 +730,6 @@ start_journal_io:
 			blkdev_issue_flush(journal->j_dev, NULL);
 	}
 
-	/*
-	 * This is the right place to wait for data buffers both for ASYNC
-	 * and !ASYNC commit. If commit is ASYNC, we need to wait only after
-	 * the commit block went to disk (which happens above). If commit is
-	 * SYNC, we need to wait for data buffers before we start writing
-	 * commit block, which happens below in such setting.
-	 */
 	err = journal_finish_inode_data_buffers(journal, commit_transaction);
 	if (err) {
 		printk(KERN_WARNING
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index f1011f7f3d41..638ce4554c76 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -653,6 +653,7 @@ struct transaction_s
 	 * waiting for it to finish.
 	 */
 	unsigned int t_synchronous_commit:1;
+	unsigned int t_flushed_data_blocks:1;
 
 	/*
 	 * For use by the filesystem to store fs-specific data