1/*
 2 * JFFS2 -- Journalling Flash File System, Version 2.
 3 *
 4 * Copyright © 2001-2007 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 */
11
 
 
12#include <linux/kernel.h>
13#include <linux/fs.h>
14#include <linux/namei.h>
15#include "nodelist.h"
16
17static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd);
18
19const struct inode_operations jffs2_symlink_inode_operations =
20{
21	.readlink =	generic_readlink,
22	.follow_link =	jffs2_follow_link,
23	.get_acl =	jffs2_get_acl,
24	.setattr =	jffs2_setattr,
25	.setxattr =	jffs2_setxattr,
26	.getxattr =	jffs2_getxattr,
27	.listxattr =	jffs2_listxattr,
28	.removexattr =	jffs2_removexattr
29};
30
31static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd)
32{
33	struct jffs2_inode_info *f = JFFS2_INODE_INFO(dentry->d_inode);
34	char *p = (char *)f->target;
35
36	/*
37	 * We don't acquire the f->sem mutex here since the only data we
38	 * use is f->target.
39	 *
40	 * 1. If we are here the inode has already built and f->target has
41	 * to point to the target path.
42	 * 2. Nobody uses f->target (if the inode is symlink's inode). The
43	 * exception is inode freeing function which frees f->target. But
44	 * it can't be called while we are here and before VFS has
45	 * stopped using our f->target 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 target\n");
51		p = ERR_PTR(-EIO);
52	}
53	D1(printk(KERN_DEBUG "jffs2_follow_link(): target path is '%s'\n", (char *) f->target));
 
54
55	nd_set_link(nd, p);
56
57	/*
58	 * We will unlock the f->sem mutex but VFS will use the f->target string. This is safe
59	 * since the only way that may cause f->target to be changed is iput() operation.
60	 * But VFS will not use f->target after iput() has been called.
61	 */
62	return NULL;
63}
64

 1/*
 2 * JFFS2 -- Journalling Flash File System, Version 2.
 3 *
 4 * Copyright © 2001-2007 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 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/kernel.h>
15#include <linux/fs.h>
16#include <linux/namei.h>
17#include "nodelist.h"
18
19static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd);
20
21const struct inode_operations jffs2_symlink_inode_operations =
22{
23	.readlink =	generic_readlink,
24	.follow_link =	jffs2_follow_link,
 
25	.setattr =	jffs2_setattr,
26	.setxattr =	jffs2_setxattr,
27	.getxattr =	jffs2_getxattr,
28	.listxattr =	jffs2_listxattr,
29	.removexattr =	jffs2_removexattr
30};
31
32static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd)
33{
34	struct jffs2_inode_info *f = JFFS2_INODE_INFO(dentry->d_inode);
35	char *p = (char *)f->target;
36
37	/*
38	 * We don't acquire the f->sem mutex here since the only data we
39	 * use is f->target.
40	 *
41	 * 1. If we are here the inode has already built and f->target has
42	 * to point to the target path.
43	 * 2. Nobody uses f->target (if the inode is symlink's inode). The
44	 * exception is inode freeing function which frees f->target. But
45	 * it can't be called while we are here and before VFS has
46	 * stopped using our f->target string which we provide by means of
47	 * nd_set_link() call.
48	 */
49
50	if (!p) {
51		pr_err("%s(): can't find symlink target\n", __func__);
52		p = ERR_PTR(-EIO);
53	}
54	jffs2_dbg(1, "%s(): target path is '%s'\n",
55		  __func__, (char *)f->target);
56
57	nd_set_link(nd, p);
58
59	/*
60	 * We will unlock the f->sem mutex but VFS will use the f->target string. This is safe
61	 * since the only way that may cause f->target to be changed is iput() operation.
62	 * But VFS will not use f->target after iput() has been called.
63	 */
64	return NULL;
65}
66