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/fs/freevxfs/vxfs_subr.c

https://bitbucket.org/cyanogenmod/android_kernel_asus_tf300t
C | 183 lines | 63 code | 19 blank | 101 comment | 4 complexity | 4c578b521a45a1be552670be18ef1e4d MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
  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
 41static int		vxfs_readpage(struct file *, struct page *);
 42static sector_t		vxfs_bmap(struct address_space *, sector_t);
 43
 44const struct address_space_operations vxfs_aops = {
 45	.readpage =		vxfs_readpage,
 46	.bmap =			vxfs_bmap,
 47};
 48
 49inline void
 50vxfs_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 */
 67struct page *
 68vxfs_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		 
 84fail:
 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 */
101struct buffer_head *
102vxfs_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 */
128static int
129vxfs_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 */
158static int
159vxfs_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 */
179static sector_t
180vxfs_bmap(struct address_space *mapping, sector_t block)
181{
182	return generic_block_bmap(mapping, block, vxfs_getblk);
183}