Ejemplo n.º 1
0
static int unionfs_readlink(struct dentry *dentry, char __user *buf,
			    int bufsiz)
{
	int err;
	struct dentry *parent;

	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
	parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);

	if (unlikely(!__unionfs_d_revalidate(dentry, parent, false, 0))) {
		err = -ESTALE;
		goto out;
	}

	err = __unionfs_readlink(dentry, buf, bufsiz);

out:
	unionfs_check_dentry(dentry);
	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);

	return err;
}
Ejemplo n.º 2
0
static void *unionfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
	char *buf;
	int len = PAGE_SIZE, err;
	mm_segment_t old_fs;
	struct dentry *parent;

	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
	parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);

	/* This is freed by the put_link method assuming a successful call. */
	buf = kmalloc(len, GFP_KERNEL);
	if (unlikely(!buf)) {
		err = -ENOMEM;
		goto out;
	}

	/* read the symlink, and then we will follow it */
	old_fs = get_fs();
	set_fs(KERNEL_DS);
	err = __unionfs_readlink(dentry, buf, len);
	set_fs(old_fs);
	if (err < 0) {
		kfree(buf);
		buf = NULL;
		goto out;
	}
	buf[err] = 0;
	nd_set_link(nd, buf);
	err = 0;

out:
	if (err >= 0) {
		unionfs_check_nd(nd);
		unionfs_check_dentry(dentry);
	}

	unionfs_unlock_dentry(dentry);
	unionfs_unlock_parent(dentry, parent);
	unionfs_read_unlock(dentry->d_sb);

	return ERR_PTR(err);
}