linux/fs/jffs2/symlink.c
KaiGai Kohei aa98d7cf59 [JFFS2][XATTR] XATTR support on JFFS2 (version. 5)
This attached patches provide xattr support including POSIX-ACL and
SELinux support on JFFS2 (version.5).

There are some significant differences from previous version posted
at last December.
The biggest change is addition of EBS(Erase Block Summary) support.
Currently, both kernel and usermode utility (sumtool) can recognize
xattr nodes which have JFFS2_NODETYPE_XATTR/_XREF nodetype.

In addition, some bugs are fixed.
- A potential race condition was fixed.
- Unexpected fail when updating a xattr by same name/value pair was fixed.
- A bug when removing xattr name/value pair was fixed.

The fundamental structures (such as using two new nodetypes and exclusion
mechanism by rwsem) are unchanged. But most of implementation were reviewed
and updated if necessary.
Espacially, we had to change several internal implementations related to
load_xattr_datum() to avoid a potential race condition.

[1/2] xattr_on_jffs2.kernel.version-5.patch
[2/2] xattr_on_jffs2.utils.version-5.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-05-13 15:09:47 +09:00

68 lines
1.9 KiB
C

/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright (C) 2001, 2002 Red Hat, Inc.
*
* Created by David Woodhouse <dwmw2@infradead.org>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
* $Id: symlink.c,v 1.19 2005/11/07 11:14:42 gleixner Exp $
*
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include "nodelist.h"
static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd);
struct inode_operations jffs2_symlink_inode_operations =
{
.readlink = generic_readlink,
.follow_link = jffs2_follow_link,
.permission = jffs2_permission,
.setattr = jffs2_setattr,
.setxattr = jffs2_setxattr,
.getxattr = jffs2_getxattr,
.listxattr = jffs2_listxattr,
.removexattr = jffs2_removexattr
};
static void *jffs2_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct jffs2_inode_info *f = JFFS2_INODE_INFO(dentry->d_inode);
char *p = (char *)f->target;
/*
* We don't acquire the f->sem mutex here since the only data we
* use is f->target.
*
* 1. If we are here the inode has already built and f->target has
* to point to the target path.
* 2. Nobody uses f->target (if the inode is symlink's inode). The
* exception is inode freeing function which frees f->target. But
* it can't be called while we are here and before VFS has
* stopped using our f->target string which we provide by means of
* nd_set_link() call.
*/
if (!p) {
printk(KERN_ERR "jffs2_follow_link(): can't find symlink taerget\n");
p = ERR_PTR(-EIO);
}
D1(printk(KERN_DEBUG "jffs2_follow_link(): target path is '%s'\n", (char *) f->target));
nd_set_link(nd, p);
/*
* We will unlock the f->sem mutex but VFS will use the f->target string. This is safe
* since the only way that may cause f->target to be changed is iput() operation.
* But VFS will not use f->target after iput() has been called.
*/
return NULL;
}