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1da177e4 LT |
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> | |
1da177e4 LT |
36 | #include <linux/pagemap.h> |
37 | ||
1da177e4 LT |
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 | ||
f5e54d6e | 44 | const struct address_space_operations vxfs_aops = { |
1da177e4 LT |
45 | .readpage = vxfs_readpage, |
46 | .bmap = vxfs_bmap, | |
1da177e4 LT |
47 | }; |
48 | ||
49 | inline void | |
50 | vxfs_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 | */ | |
67 | struct page * | |
68 | vxfs_get_page(struct address_space *mapping, u_long n) | |
69 | { | |
70 | struct page * pp; | |
71 | ||
090d2b18 | 72 | pp = read_mapping_page(mapping, n, NULL); |
1da177e4 LT |
73 | |
74 | if (!IS_ERR(pp)) { | |
1da177e4 | 75 | kmap(pp); |
1da177e4 LT |
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 | } |