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/slab.h> 37 #include <linux/pagemap.h> 38 39 #include "vxfs_extern.h" 40 41 42 static int vxfs_readpage(struct file *, struct page *); 43 static sector_t vxfs_bmap(struct address_space *, sector_t); 44 45 const struct address_space_operations vxfs_aops = { 46 .readpage = vxfs_readpage, 47 .bmap = vxfs_bmap, 48 .sync_page = block_sync_page, 49 }; 50 51 inline void 52 vxfs_put_page(struct page *pp) 53 { 54 kunmap(pp); 55 page_cache_release(pp); 56 } 57 58 /** 59 * vxfs_get_page - read a page into memory. 60 * @ip: inode to read from 61 * @n: page number 62 * 63 * Description: 64 * vxfs_get_page reads the @n th page of @ip into the pagecache. 65 * 66 * Returns: 67 * The wanted page on success, else a NULL pointer. 68 */ 69 struct page * 70 vxfs_get_page(struct address_space *mapping, u_long n) 71 { 72 struct page * pp; 73 74 pp = read_mapping_page(mapping, n, NULL); 75 76 if (!IS_ERR(pp)) { 77 kmap(pp); 78 /** if (!PageChecked(pp)) **/ 79 /** vxfs_check_page(pp); **/ 80 if (PageError(pp)) 81 goto fail; 82 } 83 84 return (pp); 85 86 fail: 87 vxfs_put_page(pp); 88 return ERR_PTR(-EIO); 89 } 90 91 /** 92 * vxfs_bread - read buffer for a give inode,block tuple 93 * @ip: inode 94 * @block: logical block 95 * 96 * Description: 97 * The vxfs_bread function reads block no @block of 98 * @ip into the buffercache. 99 * 100 * Returns: 101 * The resulting &struct buffer_head. 102 */ 103 struct buffer_head * 104 vxfs_bread(struct inode *ip, int block) 105 { 106 struct buffer_head *bp; 107 daddr_t pblock; 108 109 pblock = vxfs_bmap1(ip, block); 110 bp = sb_bread(ip->i_sb, pblock); 111 112 return (bp); 113 } 114 115 /** 116 * vxfs_get_block - locate buffer for given inode,block tuple 117 * @ip: inode 118 * @iblock: logical block 119 * @bp: buffer skeleton 120 * @create: %TRUE if blocks may be newly allocated. 121 * 122 * Description: 123 * The vxfs_get_block function fills @bp with the right physical 124 * block and device number to perform a lowlevel read/write on 125 * it. 126 * 127 * Returns: 128 * Zero on success, else a negativ error code (-EIO). 129 */ 130 static int 131 vxfs_getblk(struct inode *ip, sector_t iblock, 132 struct buffer_head *bp, int create) 133 { 134 daddr_t pblock; 135 136 pblock = vxfs_bmap1(ip, iblock); 137 if (pblock != 0) { 138 map_bh(bp, ip->i_sb, pblock); 139 return 0; 140 } 141 142 return -EIO; 143 } 144 145 /** 146 * vxfs_readpage - read one page synchronously into the pagecache 147 * @file: file context (unused) 148 * @page: page frame to fill in. 149 * 150 * Description: 151 * The vxfs_readpage routine reads @page synchronously into the 152 * pagecache. 153 * 154 * Returns: 155 * Zero on success, else a negative error code. 156 * 157 * Locking status: 158 * @page is locked and will be unlocked. 159 */ 160 static int 161 vxfs_readpage(struct file *file, struct page *page) 162 { 163 return block_read_full_page(page, vxfs_getblk); 164 } 165 166 /** 167 * vxfs_bmap - perform logical to physical block mapping 168 * @mapping: logical to physical mapping to use 169 * @block: logical block (relative to @mapping). 170 * 171 * Description: 172 * Vxfs_bmap find out the corresponding phsical block to the 173 * @mapping, @block pair. 174 * 175 * Returns: 176 * Physical block number on success, else Zero. 177 * 178 * Locking status: 179 * We are under the bkl. 180 */ 181 static sector_t 182 vxfs_bmap(struct address_space *mapping, sector_t block) 183 { 184 return generic_block_bmap(mapping, block, vxfs_getblk); 185 } 186