NFSv4: Make nfs4_state track O_RDWR, O_RDONLY and O_WRONLY separately

 A closer reading of RFC3530 reveals that OPEN_DOWNGRADE must always
 specify a access modes that have been the argument of a previous OPEN
 operation.
 IOW: doing OPEN(O_RDWR) and then OPEN_DOWNGRADE(O_WRONLY) is forbidden
 unless the user called OPEN(O_WRONLY)

 In order to fix that, we really need to track the three possible open
 states separately.

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

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index b7f262dcb6e3..4ad5981f9375 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -182,8 +182,9 @@ struct nfs4_state {
 
         nfs4_stateid stateid;
 
-        unsigned int nreaders;
-        unsigned int nwriters;
+        unsigned int n_rdonly;
+        unsigned int n_wronly;
+        unsigned int n_rdwr;
         int state;                      /* State on the server (R,W, or RW) */
         atomic_t count;
 };