original development tree for Linux kernel GTP module; now long in mainline.
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/*
* 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/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,
};
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);
}