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_kcompat.h" 40 #include "vxfs_extern.h" 41 42 43 static int vxfs_readpage(struct file *, struct page *); 44 static sector_t vxfs_bmap(struct address_space *, sector_t); 45 46 struct address_space_operations vxfs_aops = { 47 .readpage = vxfs_readpage, 48 .bmap = vxfs_bmap, 49 .sync_page = block_sync_page, 50 }; 51 52 inline void 53 vxfs_put_page(struct page *pp) 54 { 55 kunmap(pp); 56 page_cache_release(pp); 57 } 58 59 /** 60 * vxfs_get_page - read a page into memory. 61 * @ip: inode to read from 62 * @n: page number 63 * 64 * Description: 65 * vxfs_get_page reads the @n th page of @ip into the pagecache. 66 * 67 * Returns: 68 * The wanted page on success, else a NULL pointer. 69 */ 70 struct page * 71 vxfs_get_page(struct address_space *mapping, u_long n) 72 { 73 struct page * pp; 74 75 pp = read_cache_page(mapping, n, 76 (filler_t*)mapping->a_ops->readpage, NULL); 77 78 if (!IS_ERR(pp)) { 79 wait_on_page_locked(pp); 80 kmap(pp); 81 if (!PageUptodate(pp)) 82 goto fail; 83 /** if (!PageChecked(pp)) **/ 84 /** vxfs_check_page(pp); **/ 85 if (PageError(pp)) 86 goto fail; 87 } 88 89 return (pp); 90 91 fail: 92 vxfs_put_page(pp); 93 return ERR_PTR(-EIO); 94 } 95 96 /** 97 * vxfs_bread - read buffer for a give inode,block tuple 98 * @ip: inode 99 * @block: logical block 100 * 101 * Description: 102 * The vxfs_bread function reads block no @block of 103 * @ip into the buffercache. 104 * 105 * Returns: 106 * The resulting &struct buffer_head. 107 */ 108 struct buffer_head * 109 vxfs_bread(struct inode *ip, int block) 110 { 111 struct buffer_head *bp; 112 daddr_t pblock; 113 114 pblock = vxfs_bmap1(ip, block); 115 bp = sb_bread(ip->i_sb, pblock); 116 117 return (bp); 118 } 119 120 /** 121 * vxfs_get_block - locate buffer for given inode,block tuple 122 * @ip: inode 123 * @iblock: logical block 124 * @bp: buffer skeleton 125 * @create: %TRUE if blocks may be newly allocated. 126 * 127 * Description: 128 * The vxfs_get_block function fills @bp with the right physical 129 * block and device number to perform a lowlevel read/write on 130 * it. 131 * 132 * Returns: 133 * Zero on success, else a negativ error code (-EIO). 134 */ 135 static int 136 vxfs_getblk(struct inode *ip, sector_t iblock, 137 struct buffer_head *bp, int create) 138 { 139 daddr_t pblock; 140 141 pblock = vxfs_bmap1(ip, iblock); 142 if (pblock != 0) { 143 map_bh(bp, ip->i_sb, pblock); 144 return 0; 145 } 146 147 return -EIO; 148 } 149 150 /** 151 * vxfs_readpage - read one page synchronously into the pagecache 152 * @file: file context (unused) 153 * @page: page frame to fill in. 154 * 155 * Description: 156 * The vxfs_readpage routine reads @page synchronously into the 157 * pagecache. 158 * 159 * Returns: 160 * Zero on success, else a negative error code. 161 * 162 * Locking status: 163 * @page is locked and will be unlocked. 164 */ 165 static int 166 vxfs_readpage(struct file *file, struct page *page) 167 { 168 return block_read_full_page(page, vxfs_getblk); 169 } 170 171 /** 172 * vxfs_bmap - perform logical to physical block mapping 173 * @mapping: logical to physical mapping to use 174 * @block: logical block (relative to @mapping). 175 * 176 * Description: 177 * Vxfs_bmap find out the corresponding phsical block to the 178 * @mapping, @block pair. 179 * 180 * Returns: 181 * Physical block number on success, else Zero. 182 * 183 * Locking status: 184 * We are under the bkl. 185 */ 186 static sector_t 187 vxfs_bmap(struct address_space *mapping, sector_t block) 188 { 189 return generic_block_bmap(mapping, block, vxfs_getblk); 190 } 191