Re: NFSv3 and linux-2.4.10-ac3 => oops

[Trond Myklebust]

>>>>> " " == Matt Bernstein <[e-mail]> writes:

     > I wonder if this is related to oopses I sent in in the last two
     > days?  We're running 4GB setups with NFSv3 client and server on
     > our fileservers, and the oopses might (don't really have strong
     > correlation evidence yet) be related to when our fileservers
     > push online backups to cheaper NFS servers (running the same
     > kernel based on 2.4.9-ac10). Is there a last known good kernel
     > I can try on my production systems while I try to reproduce the
     > problem on smaller boxes? Or would you like me to try your
     > patch?

Linus changed nfs_prepare_write() in his tree around 2.4.10-pre5. From
what I can see, Alan merged that particular patch into 2.4.9-ac11 (but
without merging in the related changes to linux/mm/filemap.c).

Argh. I see that in the patch I put out earlier today, I forgot to
also revert the removal of the kunmap() in nfs_commit_write() (sorry -
my coffee was particularly weak this morning).

Please apply the following patch to the 'ac' tree instead.

People who use Linus' tree should *not* apply this patch!!!!!

Cheers,
  Trond

diff -u --recursive --new-file linux-2.4.10-reclaim/fs/nfs/file.c linux-2.4.10-ac4/fs/nfs/file.c
--- linux-2.4.10-reclaim/fs/nfs/file.c	Sun Sep 23 18:48:01 2001
+++ linux-2.4.10-ac4/fs/nfs/file.c	Tue Oct  2 13:40:58 2001
@@ -155,7 +155,12 @@
  */
 static int nfs_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
 {
-	return nfs_flush_incompatible(file, page);
+	int status;
+	kmap(page);
+	status = nfs_flush_incompatible(file, page);
+	if (status)
+		kunmap(page);
+	return status;
 }
 
 static int nfs_commit_write(struct file *file, struct page *page, unsigned offset, unsigned to)
@@ -164,6 +169,7 @@
 	loff_t pos = ((loff_t)page->index<<PAGE_CACHE_SHIFT) + to;
 	struct inode *inode = page->mapping->host;
 
+	kunmap(page);
 	lock_kernel();
 	status = nfs_updatepage(file, page, offset, to-offset);
 	unlock_kernel();