cifs: have find_readable/writable_file filter by fsuid

When we implement multiuser mounts, we'll need to filter filehandles
by fsuid. Add a flag for multiuser mounts and code to filter by
fsuid when it's set.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 7294723..29a2ee8 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -78,9 +78,9 @@
 extern bool is_valid_oplock_break(struct smb_hdr *smb,
 				  struct TCP_Server_Info *);
 extern bool is_size_safe_to_change(struct cifsInodeInfo *, __u64 eof);
-extern struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *);
+extern struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *, bool);
 #ifdef CONFIG_CIFS_EXPERIMENTAL
-extern struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *);
+extern struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *, bool);
 #endif
 extern unsigned int smbCalcSize(struct smb_hdr *ptr);
 extern unsigned int smbCalcSize_LE(struct smb_hdr *ptr);