NFSv4: Fix open(O_TRUNC) and ftruncate() error handling

If the file wasn't opened for writing, then truncate and ftruncate
need to report the appropriate errors.

Reported-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

1 files changed, 12 insertions, 3 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index ba837d977a1a..f875cf305237 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1954,10 +1954,19 @@ static int nfs4_do_setattr(struct inode *inode, struct rpc_cred *cred,
         };
         int err;
         do {
-                err = nfs4_handle_exception(server,
-                                _nfs4_do_setattr(inode, cred, fattr, sattr, state),
-                                &exception);
+                err = _nfs4_do_setattr(inode, cred, fattr, sattr, state);
+                switch (err) {
+                case -NFS4ERR_OPENMODE:
+                        if (state && !(state->state & FMODE_WRITE)) {
+                                err = -EBADF;
+                                if (sattr->ia_valid & ATTR_OPEN)
+                                        err = -EACCES;
+                                goto out;
+                        }
+                }
+                err = nfs4_handle_exception(server, err, &exception);
         } while (exception.retry);
+out:
         return err;
 }