page discard on page error

[Christoph Hellwig]

On Thu, Aug 19, 2010 at 01:50:43AM +1000, Dave Chinner wrote:
> The current code does not handle EAGAIN at all, just discards the
> page. This looks incorrect - I think that EAGAIN should still cause
> the page to be redirtied, not discarded. I'm not sure if I missed
> something else, though - can you remember why you removed the EAGAIN
> case?

I don't think that was intentional, in fact I'm pretty sure I handled
it in an earlier version.  Mike, can you test the patch below?


Index: xfs/fs/xfs/linux-2.6/xfs_aops.c
===================================================================
--- xfs.orig/fs/xfs/linux-2.6/xfs_aops.c	2010-08-18 18:10:48.140261091 +0200
+++ xfs/fs/xfs/linux-2.6/xfs_aops.c	2010-08-18 18:12:41.167005888 +0200
@@ -1068,7 +1068,7 @@ xfs_vm_writepage(
 	 * by themselves.
 	 */
 	if ((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == PF_MEMALLOC)
-		goto out_fail;
+		goto redirty;
 
 	/*
 	 * We need a transaction if there are delalloc or unwritten buffers
@@ -1080,7 +1080,7 @@ xfs_vm_writepage(
 	 */
 	xfs_count_page_state(page, &delalloc, &unwritten);
 	if ((current->flags & PF_FSTRANS) && (delalloc || unwritten))
-		goto out_fail;
+		goto redirty;
 
 	/* Is this page beyond the end of the file? */
 	offset = i_size_read(inode);
@@ -1245,12 +1245,15 @@ error:
 	if (iohead)
 		xfs_cancel_ioend(iohead);
 
+	if (err == -EAGAIN)
+		goto redirty;
+
 	xfs_aops_discard_page(page);
 	ClearPageUptodate(page);
 	unlock_page(page);
 	return err;
 
-out_fail:
+redirty:
 	redirty_page_for_writepage(wbc, page);
 	unlock_page(page);
 	return 0;