diff --git a/mm/filemap.c b/mm/filemap.c
index 8332c77..7c571dd 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2044,8 +2044,9 @@ generic_file_direct_write(struct kiocb *
 	/*
 	 * Sync the fs metadata but not the minor inode changes and
 	 * of course not the data as we did direct DMA for the IO.
-	 * i_mutex is held, which protects generic_osync_inode() from
-	 * livelocking.  AIO O_DIRECT ops attempt to sync metadata here.
+	 * i_mutex may not being held (XFS does this), if so some specific locking
+	 * ordering must protect generic_osync_inode() from livelocking.
+	 * AIO O_DIRECT ops attempt to sync metadata here.
 	 */
 	if ((written >= 0 || written == -EIOCBQUEUED) &&
 	    ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
@@ -2279,6 +2280,17 @@ __generic_file_aio_write_nolock(struct k
 
 		written = generic_file_direct_write(iocb, iov, &nr_segs, pos,
 							ppos, count, ocount);
+		/*
+		 * If host is not S_ISBLK generic_file_direct_write() may 
+		 * have instantiated a few blocks outside i_size  files
+		 * Trim these off again.
+		 */
+		if (unlikely(written < 0) && !S_ISBLK(inode->i_mode)) {
+			loff_t isize = i_size_read(inode);
+			if (pos + count > isize)
+				vmtruncate(inode, isize);
+		}
+
 		if (written < 0 || written == count)
 			goto out;
 		/*
@@ -2341,6 +2353,13 @@ ssize_t generic_file_aio_write_nolock(st
 	ssize_t ret;
 
 	BUG_ON(iocb->ki_pos != pos);
+	/*
+	 *  generic_file_buffered_write() may be called inside 
+	 *  __generic_file_aio_write_nolock() even in case of
+	 *  O_DIRECT for non S_ISBLK files. So i_mutex must be held.
+	 */
+	if (!S_ISBLK(inode->i_mode))
+		BUG_ON(!mutex_is_locked(&inode->i_mutex));
 
 	ret = __generic_file_aio_write_nolock(iocb, iov, nr_segs,
 			&iocb->ki_pos);
@@ -2383,8 +2402,8 @@ ssize_t generic_file_aio_write(struct ki
 EXPORT_SYMBOL(generic_file_aio_write);
 
 /*
- * Called under i_mutex for writes to S_ISREG files.   Returns -EIO if something
- * went wrong during pagecache shootdown.
+ * May be called without i_mutex for writes to S_ISREG files. XFS does this.
+ * Returns -EIO if something went wrong during pagecache shootdown.
  */
 static ssize_t
 generic_file_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,