[PATCH] nfsd4: nfsd oopsed when encountering a conflict with a local lock

Bug Fix: Non NFSD conflicting byte-range locks were causing an Oops.

Encode a zero length owner and zero clientid for non NFSD conflicting locks in
the lock_denied response.
Signed-off-by: Andy Adamson <andros@umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/nfsd/nfs4xdr.c

@@ -1995,13 +1995,18 @@ nfsd4_encode_lock_denied(struct nfsd4_compoundres *resp, struct nfsd4_lock_denie
 {
 	ENCODE_HEAD;
 
-	RESERVE_SPACE(32 + XDR_LEN(ld->ld_sop->so_owner.len));
+	RESERVE_SPACE(32 + XDR_LEN(ld->ld_sop ? ld->ld_sop->so_owner.len : 0));
 	WRITE64(ld->ld_start);
 	WRITE64(ld->ld_length);
 	WRITE32(ld->ld_type);
-	WRITEMEM(&ld->ld_sop->so_client->cl_clientid, 8);
-	WRITE32(ld->ld_sop->so_owner.len);
-	WRITEMEM(ld->ld_sop->so_owner.data, ld->ld_sop->so_owner.len);
+	if (ld->ld_sop) {
+		WRITEMEM(&ld->ld_sop->so_client->cl_clientid, 8);
+		WRITE32(ld->ld_sop->so_owner.len);
+		WRITEMEM(ld->ld_sop->so_owner.data, ld->ld_sop->so_owner.len);
+	}  else {  /* non - nfsv4 lock in conflict, no clientid nor owner */
+		WRITE64((u64)0); /* clientid */
+		WRITE32(0); /* length of owner name */
+	}
 	ADJUST_ARGS();
 }