fs/freevxfs/vxfs_subr.c

   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 }