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1da177e4 LT |
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 | * | |
32f1a95d | 10 | * $Id: symlink.c,v 1.16 2005/03/01 10:50:48 dedekind Exp $ |
1da177e4 LT |
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); | |
1da177e4 LT |
22 | |
23 | struct inode_operations jffs2_symlink_inode_operations = | |
24 | { | |
25 | .readlink = generic_readlink, | |
26 | .follow_link = jffs2_follow_link, | |
1da177e4 LT |
27 | .setattr = jffs2_setattr |
28 | }; | |
29 | ||
30 | static int jffs2_follow_link(struct dentry *dentry, struct nameidata *nd) | |
31 | { | |
32f1a95d AB |
32 | struct jffs2_inode_info *f = JFFS2_INODE_INFO(dentry->d_inode); |
33 | ||
34 | /* | |
35 | * We don't acquire the f->sem mutex here since the only data we | |
36 | * use is f->dents which in case of the symlink inode points to the | |
37 | * symlink's target path. | |
38 | * | |
39 | * 1. If we are here the inode has already built and f->dents has | |
40 | * to point to the target path. | |
41 | * 2. Nobody uses f->dents (if the inode is symlink's inode). The | |
42 | * exception is inode freeing function which frees f->dents. But | |
43 | * it can't be called while we are here and before VFS has | |
44 | * stopped using our f->dents string which we provide by means of | |
45 | * nd_set_link() call. | |
46 | */ | |
47 | ||
48 | if (!f->dents) { | |
49 | printk(KERN_ERR "jffs2_follow_link(): can't find symlink taerget\n"); | |
50 | return -EIO; | |
51 | } | |
52 | D1(printk(KERN_DEBUG "jffs2_follow_link(): target path is '%s'\n", (char *) f->dents)); | |
53 | ||
54 | nd_set_link(nd, (char *)f->dents); | |
55 | ||
56 | /* | |
57 | * We unlock the f->sem mutex but VFS will use the f->dents string. This is safe | |
58 | * since the only way that may cause f->dents to be changed is iput() operation. | |
59 | * But VFS will not use f->dents after iput() has been called. | |
60 | */ | |
1da177e4 LT |
61 | return 0; |
62 | } | |
63 |