Messages in this thread |  | | | Date | Thu, 7 Feb 2008 18:48:18 -0800 | | From | Andrew Morton <> | | Subject | Re: [GIT] Please pull 2 NFS client fixes |
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On Thu, 07 Feb 2008 20:07:21 -0500 Trond Myklebust <Trond.Myklebust@netapp.com> wrote:
> commit 5d47a35600270e7115061cb1320ee60ae9bcb6b8 > Author: Trond Myklebust <Trond.Myklebust@netapp.com> > Date: Thu Feb 7 17:24:07 2008 -0500 > > 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()).
Is this one worth feeding back into 2.6.24.x? (for various values of "4"?)
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