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 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 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 } 184