Return-Path: Received: from fieldses.org ([173.255.197.46]:58393 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751104AbbIQNZx (ORCPT ); Thu, 17 Sep 2015 09:25:53 -0400 Date: Thu, 17 Sep 2015 09:25:52 -0400 From: "J. Bruce Fields" To: Anna Schumaker Cc: Trond Myklebust , Anna Schumaker , linux-nfs@vger.kernel.org Subject: Re: [PATCH] nfs: fix v4.2 SEEK on files over 2 gigs Message-ID: <20150917132552.GD9870@fieldses.org> References: <20150916212127.GA5169@fieldses.org> <55FABA40.6010406@Netapp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <55FABA40.6010406@Netapp.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Sep 17, 2015 at 09:04:00AM -0400, Anna Schumaker wrote: > Hey Bruce, > > I actually worked on a version of this patch on my own yesterday, too. Looks like you beat me to submitting it! :) Oh, OK, well feel free to credit it however you'd like. > On 09/16/2015 05:21 PM, J. Bruce Fields wrote: > > From: "J. Bruce Fields" > > > > We're incorrectly assigning a loff_t return to an int. If SEEK_HOLE or > > SEEK_DATA returns an offset over 2^31 then the application will see a > > weird lseek() result (usually -EIO). > > I saw roughly the same thing with xfstests generic/285. I maybe should have included my reproducer in the changelog, which was: git clone git://git.infradead.org/users/dedekind/bmap-tools.git cd bmap-tools mount overs=4.2 localhost:/exports /mnt/ dd if=/dev/zero of=/mnt/test1.image seek=2097152 bs=1K count=1 ./bmaptool create /mnt/test1.image In the good case it outputs some xml, in the bad case it aborts with an IO error. --b. > > Cc: stable@vger.kernel.org > > Fixes: bdcc2cd14e4e "NFSv4.2: handle NFS-specific llseek errors" > > Signed-off-by: J. Bruce Fields > > Reviewed-by: Anna Schumaker > > > --- > > fs/nfs/nfs42proc.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c > > index d731bbf974aa..0f020e4d8421 100644 > > --- a/fs/nfs/nfs42proc.c > > +++ b/fs/nfs/nfs42proc.c > > @@ -175,10 +175,12 @@ loff_t nfs42_proc_llseek(struct file *filep, loff_t offset, int whence) > > { > > struct nfs_server *server = NFS_SERVER(file_inode(filep)); > > struct nfs4_exception exception = { }; > > - int err; > > + loff_t err; > > > > do { > > err = _nfs42_proc_llseek(filep, offset, whence); > > + if (err >= 0) > > + break; > > if (err == -ENOTSUPP) > > return -EOPNOTSUPP; > > err = nfs4_handle_exception(server, err, &exception); > >