xfs: refactor the tail of xfs_writepage_map

Rejuggle how we deal with the different error vs non-error and have
ioends vs not have ioend cases to keep the fast path streamlined, and
the duplicate code at a minimum.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index af9224ea4ebf447485fcfd1ebd47bd6cacd22134..c8e0d3055153dd1e1350c761b2d32cc49db77171 100644 (file)
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -854,7 +854,14 @@ xfs_writepage_map(
         * submission of outstanding ioends on the writepage context so they are
         * treated correctly on error.
         */
-       if (count) {
+       if (unlikely(error)) {
+               if (!count) {
+                       xfs_aops_discard_page(page);
+                       ClearPageUptodate(page);
+                       unlock_page(page);
+                       goto done;
+               }
+
                /*
                 * If the page was not fully cleaned, we need to ensure that the
                 * higher layers come back to it correctly.  That means we need
@@ -863,43 +870,35 @@ xfs_writepage_map(
                 * so another attempt to write this page in this writeback sweep
                 * will be made.
                 */
-               if (error) {
-                       set_page_writeback_keepwrite(page);
-               } else {
-                       clear_page_dirty_for_io(page);
-                       set_page_writeback(page);
-               }
-               unlock_page(page);
-
-               /*
-                * Preserve the original error if there was one, otherwise catch
-                * submission errors here and propagate into subsequent ioend
-                * submissions.
-                */
-               list_for_each_entry_safe(ioend, next, &submit_list, io_list) {
-                       int error2;
-
-                       list_del_init(&ioend->io_list);
-                       error2 = xfs_submit_ioend(wbc, ioend, error);
-                       if (error2 && !error)
-                               error = error2;
-               }
-       } else if (error) {
-               xfs_aops_discard_page(page);
-               ClearPageUptodate(page);
-               unlock_page(page);
+               set_page_writeback_keepwrite(page);
        } else {
-               /*
-                * We can end up here with no error and nothing to write if we
-                * race with a partial page truncate on a sub-page block sized
-                * filesystem. In that case we need to mark the page clean.
-                */
                clear_page_dirty_for_io(page);
                set_page_writeback(page);
-               unlock_page(page);
-               end_page_writeback(page);
        }
 
+       unlock_page(page);
+
+       /*
+        * Preserve the original error if there was one, otherwise catch
+        * submission errors here and propagate into subsequent ioend
+        * submissions.
+        */
+       list_for_each_entry_safe(ioend, next, &submit_list, io_list) {
+               int error2;
+
+               list_del_init(&ioend->io_list);
+               error2 = xfs_submit_ioend(wbc, ioend, error);
+               if (error2 && !error)
+                       error = error2;
+       }
+
+       /*
+        * We can end up here with no error and nothing to write if we race with
+        * a partial page truncate on a sub-page block sized filesystem.
+        */
+       if (!count)
+               end_page_writeback(page);
+done:
        mapping_set_error(page->mapping, error);
        return error;
 }