[linux-block.git] / fs / freevxfs / vxfs_subr.c

/*
 * Copyright (c) 2000-2001 Christoph Hellwig.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL").
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Veritas filesystem driver - shared subroutines.
 */
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/pagemap.h>

#include "vxfs_extern.h"


static int		vxfs_readpage(struct file *, struct page *);
static sector_t		vxfs_bmap(struct address_space *, sector_t);

const struct address_space_operations vxfs_aops = {
	.readpage =		vxfs_readpage,
	.bmap =			vxfs_bmap,
	.sync_page =		block_sync_page,
};

inline void
vxfs_put_page(struct page *pp)
{
	kunmap(pp);
	page_cache_release(pp);
}

/**
 * vxfs_get_page - read a page into memory.
 * @ip:		inode to read from
 * @n:		page number
 *
 * Description:
 *   vxfs_get_page reads the @n th page of @ip into the pagecache.
 *
 * Returns:
 *   The wanted page on success, else a NULL pointer.
 */
struct page *
vxfs_get_page(struct address_space *mapping, u_long n)
{
	struct page *			pp;

	pp = read_mapping_page(mapping, n, NULL);

	if (!IS_ERR(pp)) {
		kmap(pp);
		/** if (!PageChecked(pp)) **/
			/** vxfs_check_page(pp); **/
		if (PageError(pp))
			goto fail;
	}
	
	return (pp);
		 
fail:
	vxfs_put_page(pp);
	return ERR_PTR(-EIO);
}

/**
 * vxfs_bread - read buffer for a give inode,block tuple
 * @ip:		inode
 * @block:	logical block
 *
 * Description:
 *   The vxfs_bread function reads block no @block  of
 *   @ip into the buffercache.
 *
 * Returns:
 *   The resulting &struct buffer_head.
 */
struct buffer_head *
vxfs_bread(struct inode *ip, int block)
{
	struct buffer_head	*bp;
	daddr_t			pblock;

	pblock = vxfs_bmap1(ip, block);
	bp = sb_bread(ip->i_sb, pblock);

	return (bp);
}

/**
 * vxfs_get_block - locate buffer for given inode,block tuple 
 * @ip:		inode
 * @iblock:	logical block
 * @bp:		buffer skeleton
 * @create:	%TRUE if blocks may be newly allocated.
 *
 * Description:
 *   The vxfs_get_block function fills @bp with the right physical
 *   block and device number to perform a lowlevel read/write on
 *   it.
 *
 * Returns:
 *   Zero on success, else a negativ error code (-EIO).
 */
static int
vxfs_getblk(struct inode *ip, sector_t iblock,
	    struct buffer_head *bp, int create)
{
	daddr_t			pblock;

	pblock = vxfs_bmap1(ip, iblock);
	if (pblock != 0) {
		map_bh(bp, ip->i_sb, pblock);
		return 0;
	}

	return -EIO;
}

/**
 * vxfs_readpage - read one page synchronously into the pagecache
 * @file:	file context (unused)
 * @page:	page frame to fill in.
 *
 * Description:
 *   The vxfs_readpage routine reads @page synchronously into the
 *   pagecache.
 *
 * Returns:
 *   Zero on success, else a negative error code.
 *
 * Locking status:
 *   @page is locked and will be unlocked.
 */
static int
vxfs_readpage(struct file *file, struct page *page)
{
	return block_read_full_page(page, vxfs_getblk);
}
 
/**
 * vxfs_bmap - perform logical to physical block mapping
 * @mapping:	logical to physical mapping to use
 * @block:	logical block (relative to @mapping).
 *
 * Description:
 *   Vxfs_bmap find out the corresponding phsical block to the
 *   @mapping, @block pair.
 *
 * Returns:
 *   Physical block number on success, else Zero.
 *
 * Locking status:
 *   We are under the bkl.
 */
static sector_t
vxfs_bmap(struct address_space *mapping, sector_t block)
{
	return generic_block_bmap(mapping, block, vxfs_getblk);
}
Commit	Line	Data
1da177e4 LT	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
1da177e4 LT	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
f5e54d6e	45	const struct address_space_operations vxfs_aops = {
1da177e4 LT	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
090d2b18	74	pp = read_mapping_page(mapping, n, NULL);
1da177e4 LT	75
1da177e4 LT	76	if (!IS_ERR(pp)) {
1da177e4	77	kmap(pp);
1da177e4 LT	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	}