xfs: fix the multi-segment log buffer format

Per Dave Chinner suggestion, this patch:
 1) Corrects the detection of whether a multi-segment buffer is
    still tracking data.
 2) Clears all the buffer log formats for a multi-segment buffer.

Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index c48e60b..77b0975 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -611,7 +611,7 @@
 {
 	struct xfs_buf_log_item	*bip = BUF_ITEM(lip);
 	struct xfs_buf		*bp = bip->bli_buf;
-	int			aborted;
+	int			aborted, clean, i;
 	uint			hold;
 
 	/* Clear the buffer's association with this transaction. */
@@ -654,8 +654,15 @@
 	 * If the buf item isn't tracking any data, free it, otherwise drop the
 	 * reference we hold to it.
 	 */
-	if (xfs_bitmap_empty(bip->__bli_format.blf_data_map,
-			     bip->__bli_format.blf_map_size))
+	clean = 1;
+	for (i = 0; i < bip->bli_format_count; i++) {
+		if (!xfs_bitmap_empty(bip->bli_formats[i].blf_data_map,
+			     bip->bli_formats[i].blf_map_size)) {
+			clean = 0;
+			break;
+		}
+	}
+	if (clean)
 		xfs_buf_item_relse(bp);
 	else
 		atomic_dec(&bip->bli_refcount);