1 /* 2 * JFFS2 -- Journalling Flash File System, Version 2. 3 * 4 * Copyright (C) 2001, 2002 Red Hat, Inc. 5 * 6 * Created by David Woodhouse <dwmw2@infradead.org> 7 * 8 * For licensing information, see the file 'LICENCE' in this directory. 9 * 10 * $Id: symlink.c,v 1.16 2005/03/01 10:50:48 dedekind Exp $ 11 * 12 */ 13 14 15 #include <linux/kernel.h> 16 #include <linux/slab.h> 17 #include <linux/fs.h> 18 #include <linux/namei.h> 19 #include "nodelist.h" 20 21 static int jffs2_follow_link(struct dentry *dentry, struct nameidata *nd); 22 23 struct inode_operations jffs2_symlink_inode_operations = 24 { 25 .readlink = generic_readlink, 26 .follow_link = jffs2_follow_link, 27 .setattr = jffs2_setattr 28 }; 29 30 static int jffs2_follow_link(struct dentry *dentry, struct nameidata *nd) 31 { 32 struct jffs2_inode_info *f = JFFS2_INODE_INFO(dentry->d_inode); 33 char *p = (char *)f->dents; 34 35 /* 36 * We don't acquire the f->sem mutex here since the only data we 37 * use is f->dents which in case of the symlink inode points to the 38 * symlink's target path. 39 * 40 * 1. If we are here the inode has already built and f->dents has 41 * to point to the target path. 42 * 2. Nobody uses f->dents (if the inode is symlink's inode). The 43 * exception is inode freeing function which frees f->dents. But 44 * it can't be called while we are here and before VFS has 45 * stopped using our f->dents string which we provide by means of 46 * nd_set_link() call. 47 */ 48 49 if (!p) { 50 printk(KERN_ERR "jffs2_follow_link(): can't find symlink taerget\n"); 51 p = ERR_PTR(-EIO); 52 } else { 53 D1(printk(KERN_DEBUG "jffs2_follow_link(): target path is '%s'\n", (char *) f->dents)); 54 } 55 56 nd_set_link(nd, p); 57 58 /* 59 * We unlock the f->sem mutex but VFS will use the f->dents string. This is safe 60 * since the only way that may cause f->dents to be changed is iput() operation. 61 * But VFS will not use f->dents after iput() has been called. 62 */ 63 return 0; 64 } 65 66