[deliverable/linux.git] / fs / ext2 / xip.c

/*
 *  linux/fs/ext2/xip.c
 *
 * Copyright (C) 2005 IBM Corporation
 * Author: Carsten Otte (cotte@de.ibm.com)
 */

#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/buffer_head.h>
#include <linux/ext2_fs_sb.h>
#include <linux/ext2_fs.h>
#include "ext2.h"
#include "xip.h"

static inline int
__inode_direct_access(struct inode *inode, sector_t sector,
		      unsigned long *data)
{
	BUG_ON(!inode->i_sb->s_bdev->bd_disk->fops->direct_access);
	return inode->i_sb->s_bdev->bd_disk->fops
		->direct_access(inode->i_sb->s_bdev,sector,data);
}

static inline int
__ext2_get_sector(struct inode *inode, sector_t offset, int create,
		   sector_t *result)
{
	struct buffer_head tmp;
	int rc;

	memset(&tmp, 0, sizeof(struct buffer_head));
	rc = ext2_get_block(inode, offset/ (PAGE_SIZE/512), &tmp,
			    create);
	*result = tmp.b_blocknr;

	/* did we get a sparse block (hole in the file)? */
	if (!tmp.b_blocknr && !rc) {
		BUG_ON(create);
		rc = -ENODATA;
	}

	return rc;
}

int
ext2_clear_xip_target(struct inode *inode, int block)
{
	sector_t sector = block * (PAGE_SIZE/512);
	unsigned long data;
	int rc;

	rc = __inode_direct_access(inode, sector, &data);
	if (!rc)
		clear_page((void*)data);
	return rc;
}

void ext2_xip_verify_sb(struct super_block *sb)
{
	struct ext2_sb_info *sbi = EXT2_SB(sb);

	if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
	    !sb->s_bdev->bd_disk->fops->direct_access) {
		sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
		ext2_warning(sb, __FUNCTION__,
			     "ignoring xip option - not supported by bdev");
	}
}

struct page *
ext2_get_xip_page(struct address_space *mapping, sector_t offset,
		   int create)
{
	int rc;
	unsigned long data;
	sector_t sector;

	/* first, retrieve the sector number */
	rc = __ext2_get_sector(mapping->host, offset, create, &sector);
	if (rc)
		goto error;

	/* retrieve address of the target data */
	rc = __inode_direct_access
		(mapping->host, sector * (PAGE_SIZE/512), &data);
	if (!rc)
		return virt_to_page(data);

 error:
	return ERR_PTR(rc);
}
Commit	Line	Data
6d79125b CO	1	/*
	2	* linux/fs/ext2/xip.c
	3	*
	4	* Copyright (C) 2005 IBM Corporation
	5	* Author: Carsten Otte (cotte@de.ibm.com)
	6	*/
	7
	8	#include <linux/mm.h>
	9	#include <linux/fs.h>
	10	#include <linux/genhd.h>
	11	#include <linux/buffer_head.h>
	12	#include <linux/ext2_fs_sb.h>
	13	#include <linux/ext2_fs.h>
	14	#include "ext2.h"
	15	#include "xip.h"
	16
	17	static inline int
afa597ba CO	18	__inode_direct_access(struct inode *inode, sector_t sector,
	19	unsigned long *data)
	20	{
6d79125b CO	21	BUG_ON(!inode->i_sb->s_bdev->bd_disk->fops->direct_access);
	22	return inode->i_sb->s_bdev->bd_disk->fops
	23	->direct_access(inode->i_sb->s_bdev,sector,data);
	24	}
	25
afa597ba CO	26	static inline int
	27	__ext2_get_sector(struct inode *inode, sector_t offset, int create,
	28	sector_t *result)
	29	{
	30	struct buffer_head tmp;
	31	int rc;
	32
	33	memset(&tmp, 0, sizeof(struct buffer_head));
	34	rc = ext2_get_block(inode, offset/ (PAGE_SIZE/512), &tmp,
	35	create);
	36	*result = tmp.b_blocknr;
	37
	38	/* did we get a sparse block (hole in the file)? */
0cfc11ed	39	if (!tmp.b_blocknr && !rc) {
afa597ba CO	40	BUG_ON(create);
	41	rc = -ENODATA;
	42	}
	43
	44	return rc;
	45	}
	46
6d79125b	47	int
afa597ba CO	48	ext2_clear_xip_target(struct inode *inode, int block)
	49	{
	50	sector_t sector = block * (PAGE_SIZE/512);
6d79125b CO	51	unsigned long data;
	52	int rc;
	53
	54	rc = __inode_direct_access(inode, sector, &data);
afa597ba CO	55	if (!rc)
	56	clear_page((void*)data);
	57	return rc;
6d79125b CO	58	}
	59
	60	void ext2_xip_verify_sb(struct super_block *sb)
	61	{
	62	struct ext2_sb_info *sbi = EXT2_SB(sb);
	63
afa597ba CO	64	if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
	65	!sb->s_bdev->bd_disk->fops->direct_access) {
	66	sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
	67	ext2_warning(sb, __FUNCTION__,
	68	"ignoring xip option - not supported by bdev");
6d79125b CO	69	}
	70	}
	71
afa597ba CO	72	struct page *
afa597ba CO	73	ext2_get_xip_page(struct address_space *mapping, sector_t offset,
6d79125b CO	74	int create)
	75	{
	76	int rc;
	77	unsigned long data;
afa597ba	78	sector_t sector;
6d79125b	79
afa597ba CO	80	/* first, retrieve the sector number */
afa597ba CO	81	rc = __ext2_get_sector(mapping->host, offset, create, &sector);
6d79125b	82	if (rc)
afa597ba	83	goto error;
6d79125b	84
afa597ba	85	/* retrieve address of the target data */
6d79125b	86	rc = __inode_direct_access
afa597ba CO	87	(mapping->host, sector * (PAGE_SIZE/512), &data);
	88	if (!rc)
	89	return virt_to_page(data);
6d79125b	90
afa597ba CO	91	error:
afa597ba CO	92	return ERR_PTR(rc);
6d79125b	93	}