constify vfs_truncate()

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

fs/open.c

@@ -65,7 +65,7 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
 	return ret;
 }
 
-long vfs_truncate(struct path *path, loff_t length)
+long vfs_truncate(const struct path *path, loff_t length)
 {
 	struct inode *inode;
 	long error;

include/linux/fs.h

@@ -2253,7 +2253,7 @@ struct filename {
 	const char		iname[];
 };
 
-extern long vfs_truncate(struct path *, loff_t);
+extern long vfs_truncate(const struct path *, loff_t);
 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
 		       struct file *filp);
 extern int vfs_fallocate(struct file *file, int mode, loff_t offset,