lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 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 | static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd) |
| 34 | { |
| 35 | struct jffs2_inode_info *f = JFFS2_INODE_INFO(dentry->d_inode); |
| 36 | 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 | if (!p) { |
| 52 | 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 | return NULL; |
| 66 | } |
| 67 | |