Make set_fs_{root,pwd} take a struct path

In nearly all cases the set_fs_{root,pwd}() calls work on a struct
path. Change the function to reflect this and use path_get() here.
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/namespace.c

@@ -1650,15 +1650,14 @@ out1:
  * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
  * It can block. Requires the big lock held.
  */
-void set_fs_root(struct fs_struct *fs, struct vfsmount *mnt,
-		 struct dentry *dentry)
+void set_fs_root(struct fs_struct *fs, struct path *path)
 {
 	struct path old_root;
 
 	write_lock(&fs->lock);
 	old_root = fs->root;
-	fs->root.mnt = mntget(mnt);
-	fs->root.dentry = dget(dentry);
+	fs->root = *path;
+	path_get(path);
 	write_unlock(&fs->lock);
 	if (old_root.dentry)
 		path_put(&old_root);
@@ -1668,15 +1667,14 @@ void set_fs_root(struct fs_struct *fs, struct vfsmount *mnt,
  * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
  * It can block. Requires the big lock held.
  */
-void set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt,
-		struct dentry *dentry)
+void set_fs_pwd(struct fs_struct *fs, struct path *path)
 {
 	struct path old_pwd;
 
 	write_lock(&fs->lock);
 	old_pwd = fs->pwd;
-	fs->pwd.mnt = mntget(mnt);
-	fs->pwd.dentry = dget(dentry);
+	fs->pwd = *path;
+	path_get(path);
 	write_unlock(&fs->lock);
 
 	if (old_pwd.dentry)
@@ -1697,12 +1695,10 @@ static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
 			task_unlock(p);
 			if (fs->root.dentry == old_nd->path.dentry
 			    && fs->root.mnt == old_nd->path.mnt)
-				set_fs_root(fs, new_nd->path.mnt,
-					    new_nd->path.dentry);
+				set_fs_root(fs, &new_nd->path);
 			if (fs->pwd.dentry == old_nd->path.dentry
 			    && fs->pwd.mnt == old_nd->path.mnt)
-				set_fs_pwd(fs, new_nd->path.mnt,
-					   new_nd->path.dentry);
+				set_fs_pwd(fs, &new_nd->path);
 			put_fs_struct(fs);
 		} else
 			task_unlock(p);
@@ -1845,6 +1841,7 @@ static void __init init_mount_tree(void)
 {
 	struct vfsmount *mnt;
 	struct mnt_namespace *ns;
+	struct path root;
 
 	mnt = do_kern_mount("rootfs", 0, "rootfs", NULL);
 	if (IS_ERR(mnt))
@@ -1863,8 +1860,11 @@ static void __init init_mount_tree(void)
 	init_task.nsproxy->mnt_ns = ns;
 	get_mnt_ns(ns);
 
-	set_fs_pwd(current->fs, ns->root, ns->root->mnt_root);
-	set_fs_root(current->fs, ns->root, ns->root->mnt_root);
+	root.mnt = ns->root;
+	root.dentry = ns->root->mnt_root;
+
+	set_fs_pwd(current->fs, &root);
+	set_fs_root(current->fs, &root);
 }
 
 void __init mnt_init(void)

fs/open.c

@@ -490,7 +490,7 @@ asmlinkage long sys_chdir(const char __user * filename)
 	if (error)
 		goto dput_and_out;
 
-	set_fs_pwd(current->fs, nd.path.mnt, nd.path.dentry);
+	set_fs_pwd(current->fs, &nd.path);
 
 dput_and_out:
 	path_put(&nd.path);
@@ -501,9 +501,7 @@ out:
 asmlinkage long sys_fchdir(unsigned int fd)
 {
 	struct file *file;
-	struct dentry *dentry;
 	struct inode *inode;
-	struct vfsmount *mnt;
 	int error;
 
 	error = -EBADF;
@@ -511,9 +509,7 @@ asmlinkage long sys_fchdir(unsigned int fd)
 	if (!file)
 		goto out;
 
-	dentry = file->f_path.dentry;
-	mnt = file->f_path.mnt;
-	inode = dentry->d_inode;
+	inode = file->f_path.dentry->d_inode;
 
 	error = -ENOTDIR;
 	if (!S_ISDIR(inode->i_mode))
@@ -521,7 +517,7 @@ asmlinkage long sys_fchdir(unsigned int fd)
 
 	error = file_permission(file, MAY_EXEC);
 	if (!error)
-		set_fs_pwd(current->fs, mnt, dentry);
+		set_fs_pwd(current->fs, &file->f_path);
 out_putf:
 	fput(file);
 out:
@@ -545,7 +541,7 @@ asmlinkage long sys_chroot(const char __user * filename)
 	if (!capable(CAP_SYS_CHROOT))
 		goto dput_and_out;
 
-	set_fs_root(current->fs, nd.path.mnt, nd.path.dentry);
+	set_fs_root(current->fs, &nd.path);
 	set_fs_altroot();
 	error = 0;
 dput_and_out:

include/linux/fs_struct.h

@@ -20,8 +20,8 @@ extern struct kmem_cache *fs_cachep;
 
 extern void exit_fs(struct task_struct *);
 extern void set_fs_altroot(void);
-extern void set_fs_root(struct fs_struct *, struct vfsmount *, struct dentry *);
-extern void set_fs_pwd(struct fs_struct *, struct vfsmount *, struct dentry *);
+extern void set_fs_root(struct fs_struct *, struct path *);
+extern void set_fs_pwd(struct fs_struct *, struct path *);
 extern struct fs_struct *copy_fs_struct(struct fs_struct *);
 extern void put_fs_struct(struct fs_struct *);