1/*
2 * Copyright (c) 2000-2001 Christoph Hellwig.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions, and the following disclaimer,
10 *    without modification.
11 * 2. The name of the author may not be used to endorse or promote products
12 *    derived from this software without specific prior written permission.
13 *
14 * Alternatively, this software may be distributed under the terms of the
15 * GNU General Public License ("GPL").
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
21 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30/*
31 * Veritas filesystem driver - support for 'immed' inodes.
32 */
33#include <linux/fs.h>
34#include <linux/pagemap.h>
35#include <linux/namei.h>
36
37#include "vxfs.h"
38#include "vxfs_extern.h"
39#include "vxfs_inode.h"
40
41
42static void *	vxfs_immed_follow_link(struct dentry *, struct nameidata *);
43
44static int	vxfs_immed_readpage(struct file *, struct page *);
45
46/*
47 * Inode operations for immed symlinks.
48 *
49 * Unliked all other operations we do not go through the pagecache,
50 * but do all work directly on the inode.
51 */
52const struct inode_operations vxfs_immed_symlink_iops = {
53	.readlink =		generic_readlink,
54	.follow_link =		vxfs_immed_follow_link,
55};
56
57/*
58 * Address space operations for immed files and directories.
59 */
60const struct address_space_operations vxfs_immed_aops = {
61	.readpage =		vxfs_immed_readpage,
62};
63
64/**
65 * vxfs_immed_follow_link - follow immed symlink
66 * @dp:		dentry for the link
67 * @np:		pathname lookup data for the current path walk
68 *
69 * Description:
70 *   vxfs_immed_follow_link restarts the pathname lookup with
71 *   the data obtained from @dp.
72 *
73 * Returns:
74 *   Zero on success, else a negative error code.
75 */
76static void *
77vxfs_immed_follow_link(struct dentry *dp, struct nameidata *np)
78{
79	struct vxfs_inode_info		*vip = VXFS_INO(d_inode(dp));
80	nd_set_link(np, vip->vii_immed.vi_immed);
81	return NULL;
82}
83
84/**
85 * vxfs_immed_readpage - read part of an immed inode into pagecache
86 * @file:	file context (unused)
87 * @page:	page frame to fill in.
88 *
89 * Description:
90 *   vxfs_immed_readpage reads a part of the immed area of the
91 *   file that hosts @pp into the pagecache.
92 *
93 * Returns:
94 *   Zero on success, else a negative error code.
95 *
96 * Locking status:
97 *   @page is locked and will be unlocked.
98 */
99static int
100vxfs_immed_readpage(struct file *fp, struct page *pp)
101{
102	struct vxfs_inode_info	*vip = VXFS_INO(pp->mapping->host);
103	u_int64_t	offset = (u_int64_t)pp->index << PAGE_CACHE_SHIFT;
104	caddr_t		kaddr;
105
106	kaddr = kmap(pp);
107	memcpy(kaddr, vip->vii_immed.vi_immed + offset, PAGE_CACHE_SIZE);
108	kunmap(pp);
109
110	flush_dcache_page(pp);
111	SetPageUptodate(pp);
112        unlock_page(pp);
113
114	return 0;
115}
116