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
41 static int vxfs_readpage(struct file *, struct page *);
42 static sector_t vxfs_bmap(struct address_space *, sector_t);
43
44 const struct address_space_operations vxfs_aops = {
45 .readpage = vxfs_readpage,
46 .bmap = vxfs_bmap,
47 };
48
49 inline void
50 vxfs_put_page(struct page *pp)
51 {
52 kunmap(pp);
53 put_page(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 */
67 struct page *
68 vxfs_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
84 fail:
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 */
101 struct buffer_head *
102 vxfs_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 */
128 static int
129 vxfs_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 */
158 static int
159 vxfs_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 */
179 static sector_t
180 vxfs_bmap(struct address_space *mapping, sector_t block)
181 {
182 return generic_block_bmap(mapping, block, vxfs_getblk);
183 }