In the VOP_PUTPAGES() implementations, change the default error from

VM_PAGER_AGAIN to VM_PAGER_ERROR for the uwritten pages. Return
VM_PAGER_AGAIN for the partially written page. Always forward at least
one page in the loop of vm_object_page_clean().

VM_PAGER_ERROR causes the page reactivation and does not clear the
page dirty state, so the write is not lost.

The change fixes an infinite loop in vm_object_page_clean() when the
filesystem returns permanent errors for some page writes.

Reported and tested by:	gavin
Reviewed by:	alc, rmacklem
MFC after:	1 week

1 files changed, 4 insertions, 11 deletions

diff --git a/sys/fs/nfsclient/nfs_clbio.c b/sys/fs/nfsclient/nfs_clbio.c
index fee8b05..95138ec 100644
--- a/sys/fs/nfsclient/nfs_clbio.c
+++ b/sys/fs/nfsclient/nfs_clbio.c
@@ -302,7 +302,7 @@ ncl_putpages(struct vop_putpages_args *ap)
 	}
 
 	for (i = 0; i < npages; i++)
-		rtvals[i] = VM_PAGER_AGAIN;
+		rtvals[i] = VM_PAGER_ERROR;
 
 	/*
 	 * When putting pages, do not extend file past EOF.
@@ -345,16 +345,9 @@ ncl_putpages(struct vop_putpages_args *ap)
 	pmap_qremove(kva, npages);
 	relpbuf(bp, &ncl_pbuf_freecnt);
 
-	if (!error) {
-		int nwritten = round_page(count - uio.uio_resid) / PAGE_SIZE;
-		for (i = 0; i < nwritten; i++) {
-			rtvals[i] = VM_PAGER_OK;
-			vm_page_undirty(pages[i]);
-		}
-		if (must_commit) {
-			ncl_clearcommit(vp->v_mount);
-		}
-	}
+	vnode_pager_undirty_pages(pages, rtvals, count - uio.uio_resid);
+	if (must_commit)
+		ncl_clearcommit(vp->v_mount);
 	return rtvals[0];
 }