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" <bfields@xxxxxxxxxx>
> >
> > 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@xxxxxxxxxxxxxxx
> > Fixes: bdcc2cd14e4e "NFSv4.2: handle NFS-specific llseek errors"
> > Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
>
> Reviewed-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
>
> > ---
> > 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);
> >
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