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 - shared subroutines.
32 */
33#include <linux/fs.h>
34#include <linux/buffer_head.h>
35#include <linux/kernel.h>
36#include <linux/pagemap.h>
37
38#include "vxfs_extern.h"
39
40
41static int		vxfs_readpage(struct file *, struct page *);
42static sector_t		vxfs_bmap(struct address_space *, sector_t);
43
44const struct address_space_operations vxfs_aops = {
45	.readpage =		vxfs_readpage,
46	.bmap =			vxfs_bmap,
47};
48
49inline void
50vxfs_put_page(struct page *pp)
51{
52	kunmap(pp);
53	page_cache_release(pp);
54}
55
56/**
57 * vxfs_get_page - read a page into memory.
58 * @ip:		inode to read from
59 * @n:		page number
60 *
61 * Description:
62 *   vxfs_get_page reads the @n th page of @ip into the pagecache.
63 *
64 * Returns:
65 *   The wanted page on success, else a NULL pointer.
66 */
67struct page *
68vxfs_get_page(struct address_space *mapping, u_long n)
69{
70	struct page *			pp;
71
72	pp = read_mapping_page(mapping, n, NULL);
73
74	if (!IS_ERR(pp)) {
75		kmap(pp);
76		/** if (!PageChecked(pp)) **/
77			/** vxfs_check_page(pp); **/
78		if (PageError(pp))
79			goto fail;
80	}
81
82	return (pp);
83
84fail:
85	vxfs_put_page(pp);
86	return ERR_PTR(-EIO);
87}
88
89/**
90 * vxfs_bread - read buffer for a give inode,block tuple
91 * @ip:		inode
92 * @block:	logical block
93 *
94 * Description:
95 *   The vxfs_bread function reads block no @block  of
96 *   @ip into the buffercache.
97 *
98 * Returns:
99 *   The resulting &struct buffer_head.
100 */
101struct buffer_head *
102vxfs_bread(struct inode *ip, int block)
103{
104	struct buffer_head	*bp;
105	daddr_t			pblock;
106
107	pblock = vxfs_bmap1(ip, block);
108	bp = sb_bread(ip->i_sb, pblock);
109
110	return (bp);
111}
112
113/**
114 * vxfs_get_block - locate buffer for given inode,block tuple
115 * @ip:		inode
116 * @iblock:	logical block
117 * @bp:		buffer skeleton
118 * @create:	%TRUE if blocks may be newly allocated.
119 *
120 * Description:
121 *   The vxfs_get_block function fills @bp with the right physical
122 *   block and device number to perform a lowlevel read/write on
123 *   it.
124 *
125 * Returns:
126 *   Zero on success, else a negativ error code (-EIO).
127 */
128static int
129vxfs_getblk(struct inode *ip, sector_t iblock,
130	    struct buffer_head *bp, int create)
131{
132	daddr_t			pblock;
133
134	pblock = vxfs_bmap1(ip, iblock);
135	if (pblock != 0) {
136		map_bh(bp, ip->i_sb, pblock);
137		return 0;
138	}
139
140	return -EIO;
141}
142
143/**
144 * vxfs_readpage - read one page synchronously into the pagecache
145 * @file:	file context (unused)
146 * @page:	page frame to fill in.
147 *
148 * Description:
149 *   The vxfs_readpage routine reads @page synchronously into the
150 *   pagecache.
151 *
152 * Returns:
153 *   Zero on success, else a negative error code.
154 *
155 * Locking status:
156 *   @page is locked and will be unlocked.
157 */
158static int
159vxfs_readpage(struct file *file, struct page *page)
160{
161	return block_read_full_page(page, vxfs_getblk);
162}
163
164/**
165 * vxfs_bmap - perform logical to physical block mapping
166 * @mapping:	logical to physical mapping to use
167 * @block:	logical block (relative to @mapping).
168 *
169 * Description:
170 *   Vxfs_bmap find out the corresponding phsical block to the
171 *   @mapping, @block pair.
172 *
173 * Returns:
174 *   Physical block number on success, else Zero.
175 *
176 * Locking status:
177 *   We are under the bkl.
178 */
179static sector_t
180vxfs_bmap(struct address_space *mapping, sector_t block)
181{
182	return generic_block_bmap(mapping, block, vxfs_getblk);
183}
184