On Tue, 16 Jun 2015, Anna Schumaker wrote:
> Thanks for finding this!
>
> On 06/14/2015 05:35 PM, Benjamin Coddington wrote:
> > Don't pass along NFS4ERR_* exceptions to VFS and do recovery if needed.
> > These exceptions might look like offsets (even though they are negative) and
> > applications that used the previous behavior of seeking to eof for
> > SEEK_HOLE, and current offset for SEEK_DATA may be caught off-guard if the server
> > responds with transient errors such as NFS4ERR_GRACE.
> >
> > Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
> > ---
> > fs/nfs/nfs42proc.c | 23 +++++++++++++++--------
> > 1 files changed, 15 insertions(+), 8 deletions(-)
> >
> > diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
> > index 3a9e752..9c3c9d2 100644
> > --- a/fs/nfs/nfs42proc.c
> > +++ b/fs/nfs/nfs42proc.c
> > @@ -146,20 +146,27 @@ loff_t nfs42_proc_llseek(struct file *filep, loff_t offset, int whence)
> > .rpc_resp = &res,
> > };
> > struct nfs_server *server = NFS_SERVER(inode);
> > + struct nfs4_exception exception = { };
> > int status;
> >
> > if (!nfs_server_capable(inode, NFS_CAP_SEEK))
> > return -ENOTSUPP;
> >
> > - status = nfs42_set_rw_stateid(&args.sa_stateid, filep, FMODE_READ);
> > - if (status)
> > - return status;
> > -
> > nfs_wb_all(inode);
> > - status = nfs4_call_sync(server->client, server, &msg,
> > - &args.seq_args, &res.seq_res, 0);
> > - if (status == -ENOTSUPP)
> > - server->caps &= ~NFS_CAP_SEEK;
> > + do {
> > + status = nfs42_set_rw_stateid(&args.sa_stateid, filep, FMODE_READ);
> > + if (status)
> > + return status;
> > +
> > + status = nfs4_call_sync(server->client, server, &msg,
> > + &args.seq_args, &res.seq_res, 0);
> > + if (status == -ENOTSUPP) {
> > + server->caps &= ~NFS_CAP_SEEK;
> > + return status;
> > + }
> > + status = nfs4_handle_exception(server, status, &exception);
> > + } while (exception.retry);
> > +
>
> Other functions using the nfs4_exception structure have the exception handling in a single function, and then call something like _nfs4_proc_llseek() to set up the RPC call. Is there a reason you're not doing it that way here?
I made a first pass at it that way, but because the response's offset needs
to be passed back to vfs_setpos, it meant passing in the nfs42_seek_res * to
_nfs4_proc_llseek(), or passing it back via the retun, or other fiddling.
It ended up being much smaller and simpler to do it this way.
Let me know and I'll send it with _nfs4_proc_llseek() instead if you'd like.
Ben
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