ext4: fix the deadlock in mpage_da_map_and_submit()

If ext4_jbd2_file_inode() in mpage_da_map_and_submit() fails due to
journal abort, this function returns to caller without unlocking the
page.  It leads to the deadlock, and the patch fixes this issue by
calling mpage_da_submit_io().
Signed-off-by: NKazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/inode.c

@@ -1552,9 +1552,11 @@ static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
 
 		if (ext4_should_order_data(mpd->inode)) {
 			err = ext4_jbd2_file_inode(handle, mpd->inode);
-			if (err)
+			if (err) {
 				/* Only if the journal is aborted */
-				return;
+				mpd->retval = err;
+				goto submit_io;
+			}
 		}
 	}
 
@@ -2294,11 +2296,12 @@ static int ext4_da_writepages(struct address_space *mapping,
 			ret = 0;
 		} else if (ret == MPAGE_DA_EXTENT_TAIL) {
 			/*
-			 * got one extent now try with
-			 * rest of the pages
+			 * Got one extent now try with rest of the pages.
+			 * If mpd.retval is set -EIO, journal is aborted.
+			 * So we don't need to write any more.
 			 */
 			pages_written += mpd.pages_written;
-			ret = 0;
+			ret = mpd.retval;
 			io_done = 1;
 		} else if (wbc->nr_to_write)
 			/*