[pnfs] holey file cthon test

[J. Bruce Fields]

On Wed, Sep 06, 2006 at 11:41:48AM -0700, Garth Goodson wrote:
> Can we patch our cvs tree to fix this problem, so that we can try to get 
> the connectathon suite running?

I *think* this was probably it (I guess it was Trond's patch, not
Steve's, I misrememberd).  Does this apply to your tree?

--b.

commit 79558f3610efd7928e8882b2eaca3093b283630e
Author: Trond Myklebust <Trond.Myklebust at netapp.com>
Date:   Tue Aug 22 13:44:32 2006 -0400

    NFS: Fix issue with EIO on NFS read
    
    The problem is that we may be caching writes that would extend the file and
    create a hole in the region that we are reading. In this case, we need to
    detect the eof from the server, ensure that we zero out the pages that
    are part of the hole and mark them as up to date.
    
    Signed-off-by: Trond Myklebust <Trond.Myklebust at netapp.com>
    (cherry picked from 856b603b01b99146918c093969b6cb1b1b0f1c01 commit)

diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 65c0c5b..da9cf11 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -116,10 +116,17 @@ static void nfs_readpage_truncate_uninit
 	pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
 	base &= ~PAGE_CACHE_MASK;
 	pglen = PAGE_CACHE_SIZE - base;
-	if (pglen < remainder)
+	for (;;) {
+		if (remainder <= pglen) {
+			memclear_highpage_flush(*pages, base, remainder);
+			break;
+		}
 		memclear_highpage_flush(*pages, base, pglen);
-	else
-		memclear_highpage_flush(*pages, base, remainder);
+		pages++;
+		remainder -= pglen;
+		pglen = PAGE_CACHE_SIZE;
+		base = 0;
+	}
 }
 
 /*
@@ -476,6 +483,8 @@ static void nfs_readpage_set_pages_uptod
 	unsigned int base = data->args.pgbase;
 	struct page **pages;
 
+	if (data->res.eof)
+		count = data->args.count;
 	if (unlikely(count == 0))
 		return;
 	pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
@@ -483,11 +492,7 @@ static void nfs_readpage_set_pages_uptod
 	count += base;
 	for (;count >= PAGE_CACHE_SIZE; count -= PAGE_CACHE_SIZE, pages++)
 		SetPageUptodate(*pages);
-	/*
-	 * Was this an eof or a short read? If the latter, don't mark the page
-	 * as uptodate yet.
-	 */
-	if (count > 0 && (data->res.eof || data->args.count == data->res.count))
+	if (count != 0)
 		SetPageUptodate(*pages);
 }
 
@@ -502,6 +507,8 @@ static void nfs_readpage_set_pages_error
 	count += base;
 	for (;count >= PAGE_CACHE_SIZE; count -= PAGE_CACHE_SIZE, pages++)
 		SetPageError(*pages);
+	if (count != 0)
+		SetPageError(*pages);
 }
 
 /*