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 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_cache_page(mapping, n, 75 (filler_t*)mapping->a_ops->readpage, NULL); 76 77 if (!IS_ERR(pp)) { 78 wait_on_page_locked(pp); 79 kmap(pp); 80 if (!PageUptodate(pp)) 81 goto fail; 82 /** if (!PageChecked(pp)) **/ 83 /** vxfs_check_page(pp); **/ 84 if (PageError(pp)) 85 goto fail; 86 } 87 88 return (pp); 89 90 fail: 91 vxfs_put_page(pp); 92 return ERR_PTR(-EIO); 93 } 94 95 /** 96 * vxfs_bread - read buffer for a give inode,block tuple 97 * @ip: inode 98 * @block: logical block 99 * 100 * Description: 101 * The vxfs_bread function reads block no @block of 102 * @ip into the buffercache. 103 * 104 * Returns: 105 * The resulting &struct buffer_head. 106 */ 107 struct buffer_head * 108 vxfs_bread(struct inode *ip, int block) 109 { 110 struct buffer_head *bp; 111 daddr_t pblock; 112 113 pblock = vxfs_bmap1(ip, block); 114 bp = sb_bread(ip->i_sb, pblock); 115 116 return (bp); 117 } 118 119 /** 120 * vxfs_get_block - locate buffer for given inode,block tuple 121 * @ip: inode 122 * @iblock: logical block 123 * @bp: buffer skeleton 124 * @create: %TRUE if blocks may be newly allocated. 125 * 126 * Description: 127 * The vxfs_get_block function fills @bp with the right physical 128 * block and device number to perform a lowlevel read/write on 129 * it. 130 * 131 * Returns: 132 * Zero on success, else a negativ error code (-EIO). 133 */ 134 static int 135 vxfs_getblk(struct inode *ip, sector_t iblock, 136 struct buffer_head *bp, int create) 137 { 138 daddr_t pblock; 139 140 pblock = vxfs_bmap1(ip, iblock); 141 if (pblock != 0) { 142 map_bh(bp, ip->i_sb, pblock); 143 return 0; 144 } 145 146 return -EIO; 147 } 148 149 /** 150 * vxfs_readpage - read one page synchronously into the pagecache 151 * @file: file context (unused) 152 * @page: page frame to fill in. 153 * 154 * Description: 155 * The vxfs_readpage routine reads @page synchronously into the 156 * pagecache. 157 * 158 * Returns: 159 * Zero on success, else a negative error code. 160 * 161 * Locking status: 162 * @page is locked and will be unlocked. 163 */ 164 static int 165 vxfs_readpage(struct file *file, struct page *page) 166 { 167 return block_read_full_page(page, vxfs_getblk); 168 } 169 170 /** 171 * vxfs_bmap - perform logical to physical block mapping 172 * @mapping: logical to physical mapping to use 173 * @block: logical block (relative to @mapping). 174 * 175 * Description: 176 * Vxfs_bmap find out the corresponding phsical block to the 177 * @mapping, @block pair. 178 * 179 * Returns: 180 * Physical block number on success, else Zero. 181 * 182 * Locking status: 183 * We are under the bkl. 184 */ 185 static sector_t 186 vxfs_bmap(struct address_space *mapping, sector_t block) 187 { 188 return generic_block_bmap(mapping, block, vxfs_getblk); 189 } 190