[PATCH 5/5] vfs: define new lookup flag for chdir

[Miklos Szeredi]

In the "operation does permission checking" model used by fuse, chdir
permission is not checked, since there's no chdir method.

For this case set a lookup flag, which will be passed to
->permission(), so fuse can distinguish it from permission checks for
other operations.

Signed-off-by: Miklos Szeredi <miklos@xxxxxxxxxx>
---

Index: linux/fs/fuse/dir.c
===================================================================
--- linux.orig/fs/fuse/dir.c	2006-07-27 14:38:04.000000000 +0200
+++ linux/fs/fuse/dir.c	2006-07-27 14:38:15.000000000 +0200
@@ -776,7 +776,7 @@ static int fuse_permission(struct inode 
 		if ((mask & MAY_EXEC) && !S_ISDIR(mode) && !(mode & S_IXUGO))
 			return -EACCES;
 
-		if (nd && (nd->flags & LOOKUP_ACCESS))
+		if (nd && (nd->flags & (LOOKUP_ACCESS | LOOKUP_CHDIR)))
 			return fuse_access(inode, mask);
 		return 0;
 	}
Index: linux/fs/open.c
===================================================================
--- linux.orig/fs/open.c	2006-07-27 14:35:14.000000000 +0200
+++ linux/fs/open.c	2006-07-27 14:38:15.000000000 +0200
@@ -546,7 +546,8 @@ asmlinkage long sys_chdir(const char __u
 	struct nameidata nd;
 	int error;
 
-	error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd);
+	error = __user_walk(filename,
+			    LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_CHDIR, &nd);
 	if (error)
 		goto out;
 
Index: linux/include/linux/namei.h
===================================================================
--- linux.orig/include/linux/namei.h	2006-07-27 14:35:14.000000000 +0200
+++ linux/include/linux/namei.h	2006-07-27 14:38:15.000000000 +0200
@@ -54,6 +54,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LA
 #define LOOKUP_OPEN		(0x0100)
 #define LOOKUP_CREATE		(0x0200)
 #define LOOKUP_ACCESS		(0x0400)
+#define LOOKUP_CHDIR		(0x0800)
 
 extern int FASTCALL(__user_walk(const char __user *, unsigned, struct nameidata *));
 extern int FASTCALL(__user_walk_fd(int dfd, const char __user *, unsigned, struct nameidata *));
-
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