NLM: nlm_lookup_file() may return NLMv4-specific error codes

If the filehandle is stale, or open access is denied for some reason,
nlm_fopen() may return one of the NLMv4-specific error codes nlm4_stale_fh
or nlm4_failed. These get passed right through nlm_lookup_file(),
and so when nlmsvc_retrieve_args() calls the latter, it needs to filter
the result through the cast_status() machinery.

Failure to do so, will trigger the BUG_ON() in encode_nlm_stat...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Reported-by: Larry McVoy <lm@bitmover.com>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

2 files changed, 3 insertions, 2 deletions

diff --git a/fs/lockd/clntxdr.c b/fs/lockd/clntxdr.c
index d269ada7670..982d2676e1f 100644
--- a/fs/lockd/clntxdr.c
+++ b/fs/lockd/clntxdr.c
@@ -223,7 +223,7 @@ static void encode_nlm_stat(struct xdr_stream *xdr,
 {
         __be32 *p;
 
-        BUG_ON(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
+        WARN_ON_ONCE(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
         p = xdr_reserve_space(xdr, 4);
         *p = stat;
 }
diff --git a/fs/lockd/svcproc.c b/fs/lockd/svcproc.c
index 3009a365e08..21171f0c647 100644
--- a/fs/lockd/svcproc.c
+++ b/fs/lockd/svcproc.c
@@ -68,7 +68,8 @@ nlmsvc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
 
         /* Obtain file pointer. Not used by FREE_ALL call. */
         if (filp != NULL) {
-                if ((error = nlm_lookup_file(rqstp, &file, &lock->fh)) != 0)
+                error = cast_status(nlm_lookup_file(rqstp, &file, &lock->fh));
+                if (error != 0)
                         goto no_locks;
                 *filp = file;