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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, | |
47 | .sync_page = block_sync_page, | |
48 | }; | |
49 | ||
50 | inline void | |
51 | vxfs_put_page(struct page *pp) | |
52 | { | |
53 | kunmap(pp); | |
54 | page_cache_release(pp); | |
55 | } | |
56 | ||
57 | /** | |
58 | * vxfs_get_page - read a page into memory. | |
59 | * @ip: inode to read from | |
60 | * @n: page number | |
61 | * | |
62 | * Description: | |
63 | * vxfs_get_page reads the @n th page of @ip into the pagecache. | |
64 | * | |
65 | * Returns: | |
66 | * The wanted page on success, else a NULL pointer. | |
67 | */ | |
68 | struct page * | |
69 | vxfs_get_page(struct address_space *mapping, u_long n) | |
70 | { | |
71 | struct page * pp; | |
72 | ||
090d2b18 | 73 | pp = read_mapping_page(mapping, n, NULL); |
1da177e4 LT |
74 | |
75 | if (!IS_ERR(pp)) { | |
1da177e4 | 76 | kmap(pp); |
1da177e4 LT |
77 | /** if (!PageChecked(pp)) **/ |
78 | /** vxfs_check_page(pp); **/ | |
79 | if (PageError(pp)) | |
80 | goto fail; | |
81 | } | |
82 | ||
83 | return (pp); | |
84 | ||
85 | fail: | |
86 | vxfs_put_page(pp); | |
87 | return ERR_PTR(-EIO); | |
88 | } | |
89 | ||
90 | /** | |
91 | * vxfs_bread - read buffer for a give inode,block tuple | |
92 | * @ip: inode | |
93 | * @block: logical block | |
94 | * | |
95 | * Description: | |
96 | * The vxfs_bread function reads block no @block of | |
97 | * @ip into the buffercache. | |
98 | * | |
99 | * Returns: | |
100 | * The resulting &struct buffer_head. | |
101 | */ | |
102 | struct buffer_head * | |
103 | vxfs_bread(struct inode *ip, int block) | |
104 | { | |
105 | struct buffer_head *bp; | |
106 | daddr_t pblock; | |
107 | ||
108 | pblock = vxfs_bmap1(ip, block); | |
109 | bp = sb_bread(ip->i_sb, pblock); | |
110 | ||
111 | return (bp); | |
112 | } | |
113 | ||
114 | /** | |
115 | * vxfs_get_block - locate buffer for given inode,block tuple | |
116 | * @ip: inode | |
117 | * @iblock: logical block | |
118 | * @bp: buffer skeleton | |
119 | * @create: %TRUE if blocks may be newly allocated. | |
120 | * | |
121 | * Description: | |
122 | * The vxfs_get_block function fills @bp with the right physical | |
123 | * block and device number to perform a lowlevel read/write on | |
124 | * it. | |
125 | * | |
126 | * Returns: | |
127 | * Zero on success, else a negativ error code (-EIO). | |
128 | */ | |
129 | static int | |
130 | vxfs_getblk(struct inode *ip, sector_t iblock, | |
131 | struct buffer_head *bp, int create) | |
132 | { | |
133 | daddr_t pblock; | |
134 | ||
135 | pblock = vxfs_bmap1(ip, iblock); | |
136 | if (pblock != 0) { | |
137 | map_bh(bp, ip->i_sb, pblock); | |
138 | return 0; | |
139 | } | |
140 | ||
141 | return -EIO; | |
142 | } | |
143 | ||
144 | /** | |
145 | * vxfs_readpage - read one page synchronously into the pagecache | |
146 | * @file: file context (unused) | |
147 | * @page: page frame to fill in. | |
148 | * | |
149 | * Description: | |
150 | * The vxfs_readpage routine reads @page synchronously into the | |
151 | * pagecache. | |
152 | * | |
153 | * Returns: | |
154 | * Zero on success, else a negative error code. | |
155 | * | |
156 | * Locking status: | |
157 | * @page is locked and will be unlocked. | |
158 | */ | |
159 | static int | |
160 | vxfs_readpage(struct file *file, struct page *page) | |
161 | { | |
162 | return block_read_full_page(page, vxfs_getblk); | |
163 | } | |
164 | ||
165 | /** | |
166 | * vxfs_bmap - perform logical to physical block mapping | |
167 | * @mapping: logical to physical mapping to use | |
168 | * @block: logical block (relative to @mapping). | |
169 | * | |
170 | * Description: | |
171 | * Vxfs_bmap find out the corresponding phsical block to the | |
172 | * @mapping, @block pair. | |
173 | * | |
174 | * Returns: | |
175 | * Physical block number on success, else Zero. | |
176 | * | |
177 | * Locking status: | |
178 | * We are under the bkl. | |
179 | */ | |
180 | static sector_t | |
181 | vxfs_bmap(struct address_space *mapping, sector_t block) | |
182 | { | |
183 | return generic_block_bmap(mapping, block, vxfs_getblk); | |
184 | } |