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>
diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
index c96b44b..ffb1459 100644
--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -41,6 +41,7 @@
#define CIFS_MOUNT_MF_SYMLINKS 0x10000 /* Minshall+French Symlinks enabled */
#define CIFS_MOUNT_MULTIUSER 0x20000 /* multiuser mount */
#define CIFS_MOUNT_STRICT_IO 0x40000 /* strict cache mode */
+#define CIFS_MOUNT_RWPIDFORWARD 0x80000 /* use pid forwarding for rw */
struct cifs_sb_info {
struct rb_root tlink_tree;