PATCH info

The following set of patches fix known issues with the 2.6.25-rc1 NFS client code, and significantly enhance the support for NFSv4.

linux-2.6.25-001-fix_write_race.dif:

From: Trond Myklebust <Trond.Myklebust@netapp.com>

Date: Thu, 7 Feb 2008 17:24:07 -0500

Subject: NFS: Fix a potential file corruption issue when writing

If the inode is flagged as having an invalid mapping, then we can't rely on the PageUptodate() flag. Ensure that we don't use the "anti-fragmentation" write optimisation in nfs_updatepage(), since that will cause NFS to write out areas of the page that are no longer guaranteed to be up to date.

A potential corruption could occur in the following scenario:

client 1 client 2 =============== =============== fd=open("f",O_CREAT|O_WRONLY,0644); write(fd,"fubar\n",6); // cache last page close(fd); fd=open("f",O_WRONLY|O_APPEND); write(fd,"foo\n",4); close(fd);

fd=open("f",O_WRONLY|O_APPEND); write(fd,"bar\n",4); close(fd); ----- The bug may lead to the file "f" reading 'fubar\n\0\0\0\nbar\n' because client 2 does not update the cached page after re-opening the file for write. Instead it keeps it marked as PageUptodate() until someone calls invaldate_inode_pages2() (typically by calling read()).

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Name	Last modified	Size

Parent Directory		-
linux-2.6.25-001-fix..>	2008-02-08 00:20	2.7K
series	2008-02-08 00:20	113

NFS client patches for Linux 2.6.25-rc1