Branch data Line data Source code
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 : :
19 : : static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd);
20 : :
21 : : const struct inode_operations jffs2_symlink_inode_operations =
22 : : {
23 : : .readlink = generic_readlink,
24 : : .follow_link = jffs2_follow_link,
25 : : .get_acl = jffs2_get_acl,
26 : : .setattr = jffs2_setattr,
27 : : .setxattr = jffs2_setxattr,
28 : : .getxattr = jffs2_getxattr,
29 : : .listxattr = jffs2_listxattr,
30 : : .removexattr = jffs2_removexattr
31 : : };
32 : :
33 : 0 : static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd)
34 : : {
35 : 0 : struct jffs2_inode_info *f = JFFS2_INODE_INFO(dentry->d_inode);
36 : 0 : char *p = (char *)f->target;
37 : :
38 : : /*
39 : : * We don't acquire the f->sem mutex here since the only data we
40 : : * use is f->target.
41 : : *
42 : : * 1. If we are here the inode has already built and f->target has
43 : : * to point to the target path.
44 : : * 2. Nobody uses f->target (if the inode is symlink's inode). The
45 : : * exception is inode freeing function which frees f->target. But
46 : : * it can't be called while we are here and before VFS has
47 : : * stopped using our f->target string which we provide by means of
48 : : * nd_set_link() call.
49 : : */
50 : :
51 [ # # ]: 0 : if (!p) {
52 : 0 : pr_err("%s(): can't find symlink target\n", __func__);
53 : : p = ERR_PTR(-EIO);
54 : : }
55 : : jffs2_dbg(1, "%s(): target path is '%s'\n",
56 : : __func__, (char *)f->target);
57 : :
58 : : nd_set_link(nd, p);
59 : :
60 : : /*
61 : : * We will unlock the f->sem mutex but VFS will use the f->target string. This is safe
62 : : * since the only way that may cause f->target to be changed is iput() operation.
63 : : * But VFS will not use f->target after iput() has been called.
64 : : */
65 : 0 : return NULL;
66 : : }
67 : :
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