CIFS: Add rwpidforward mount option

Add rwpidforward mount option that switches on a mode when we forward
pid of a process who opened a file to any read and write operation.

This can prevent applications like WINE from failing on read or write
operation on a previously locked file region from the same netfd from
another process if we use mandatory brlock style.

It is actual for WINE because during a run of WINE program two processes
work on the same netfd - share the same file struct between several VFS
fds:
1) WINE-server does open and lock;
2) WINE-application does read and write.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index ca0c3789206e..310cddabd3fd 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -200,6 +200,7 @@ struct smb_vol {
         bool fsc:1;     /* enable fscache */
         bool mfsymlinks:1; /* use Minshall+French Symlinks */
         bool multiuser:1;
+        bool rwpidforward:1; /* pid forward for read/write operations */
         unsigned int rsize;
         unsigned int wsize;
         bool sockopt_tcp_nodelay:1;