NFSv4: Fix an infinite loop in the NFS state recovery code

Marten Gajda <marten.gajda@fernuni-hagen.de> states:

I tracked the problem down to the function nfs4_do_open_expired.
Within this function _nfs4_open_expired is called and may return
-NFS4ERR_DELAY. When a further call to _nfs4_open_expired is
executed and does not return -NFS4ERR_DELAY the "exception.retry"
variable is not reset to 0, causing the loop to iterate again
(and as long as err != -NFS4ERR_DELAY, probably forever)

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index e8df52dc2bc5..49eebe25bbad 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1104,8 +1104,9 @@ static inline int nfs4_do_open_expired(struct nfs_open_context *ctx, struct nfs4
 
         do {
                 err = _nfs4_open_expired(ctx, state);
-                if (err == -NFS4ERR_DELAY)
-                        nfs4_handle_exception(server, err, &exception);
+                if (err != -NFS4ERR_DELAY)
+                        break;
+                nfs4_handle_exception(server, err, &exception);
         } while (exception.retry);
         return err;
 }