exfat_blkdev.c

/*
 *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/blkdev.h>

#include "exfat_config.h"
#include "exfat_global.h"
#include "exfat_blkdev.h"
#include "exfat_data.h"
#include "exfat_api.h"
#include "exfat_super.h"

s32 bdev_init(void)
{
	return (FFS_SUCCESS);
}

s32 bdev_shutdown(void)
{
	return (FFS_SUCCESS);
}

s32 bdev_open(struct super_block *sb)
{
	BD_INFO_T *p_bd = &(EXFAT_SB(sb)->bd_info);

	if (p_bd->opened)
		return FFS_SUCCESS;

	p_bd->sector_size      = bdev_logical_block_size(sb->s_bdev);
	p_bd->sector_size_bits = my_log2(p_bd->sector_size);
	p_bd->sector_size_mask = p_bd->sector_size - 1;
	p_bd->num_sectors      = i_size_read(sb->s_bdev->bd_inode) >> p_bd->sector_size_bits;

	p_bd->opened = TRUE;

	return (FFS_SUCCESS);
}

s32 bdev_close(struct super_block *sb)
{
	BD_INFO_T *p_bd = &(EXFAT_SB(sb)->bd_info);

	if (!p_bd->opened) 
		return (FFS_SUCCESS);

	p_bd->opened = FALSE;
		return (FFS_SUCCESS);
}

s32 bdev_read(struct super_block *sb, sector_t secno, struct buffer_head **bh, u32 num_secs, s32 read)
{
	BD_INFO_T *p_bd = &(EXFAT_SB(sb)->bd_info);
	FS_INFO_T *p_fs = &(EXFAT_SB(sb)->fs_info);
#ifdef CONFIG_EXFAT_KERNEL_DEBUG
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
	long flags = sbi->debug_flags;

	if (flags & EXFAT_DEBUGFLAGS_ERROR_RW)
		return (FFS_MEDIAERR);
#endif

	if (!p_bd->opened) 
		return (FFS_MEDIAERR);

	if (*bh) __brelse(*bh);

	if (read)
		*bh = __bread(sb->s_bdev, secno, num_secs << p_bd->sector_size_bits);
	else
		*bh = __getblk(sb->s_bdev, secno, num_secs << p_bd->sector_size_bits);

	if (*bh) 
		return (FFS_SUCCESS);

	WARN(!p_fs->dev_ejected,
		"[EXFAT] No bh, device seems wrong or to be ejected.\n");

	return (FFS_MEDIAERR);
}

s32 bdev_write(struct super_block *sb, sector_t secno, struct buffer_head *bh, u32 num_secs, s32 sync)
{
	s32 count;
	struct buffer_head *bh2;
	BD_INFO_T *p_bd = &(EXFAT_SB(sb)->bd_info);
	FS_INFO_T *p_fs = &(EXFAT_SB(sb)->fs_info);
#ifdef CONFIG_EXFAT_KERNEL_DEBUG
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
	long flags = sbi->debug_flags;

	if (flags & EXFAT_DEBUGFLAGS_ERROR_RW)
		return (FFS_MEDIAERR);
#endif

	if (!p_bd->opened) 
		return (FFS_MEDIAERR);

	if (secno == bh->b_blocknr) {
		set_buffer_uptodate(bh);
		mark_buffer_dirty(bh);

		if (sync && (sync_dirty_buffer(bh) != 0))
			return (FFS_MEDIAERR);
	} else {
		count = num_secs << p_bd->sector_size_bits;

		bh2 = __getblk(sb->s_bdev, secno, count);

		if (bh2 == NULL)
			goto no_bh;

		lock_buffer(bh2);
		memcpy(bh2->b_data, bh->b_data, count);
		set_buffer_uptodate(bh2);
		mark_buffer_dirty(bh2);
		unlock_buffer(bh2);
		if (sync && (sync_dirty_buffer(bh2) != 0)) {
			__brelse(bh2);
			goto no_bh;
		}
		__brelse(bh2);
	}

	return (FFS_SUCCESS);

no_bh:
	WARN(!p_fs->dev_ejected,
		"[EXFAT] No bh, device seems wrong or to be ejected.\n");

	return (FFS_MEDIAERR);
}

s32 bdev_sync(struct super_block *sb)
{
	BD_INFO_T *p_bd = &(EXFAT_SB(sb)->bd_info);
#ifdef CONFIG_EXFAT_KERNEL_DEBUG
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
	long flags = sbi->debug_flags;

	if (flags & EXFAT_DEBUGFLAGS_ERROR_RW)
		return (FFS_MEDIAERR);
#endif

	if (!p_bd->opened)
		return (FFS_MEDIAERR);

	return sync_blockdev(sb->s_bdev);
}

s32 bdev_reada(struct super_block *sb, sector_t secno, u32 num_secs)
{
	BD_INFO_T *p_bd = &(EXFAT_SB(sb)->bd_info);
	u32 sects_per_page = (PAGE_SIZE >> sb->s_blocksize_bits);
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,38)
	struct blk_plug plug;
#endif
	u32 i;

	if (!p_bd->opened)
		return (FFS_MEDIAERR);

#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,38)
	blk_start_plug(&plug);
#endif

	for (i = 0; i < num_secs; i++) {
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,38)
		if (i && !(i & (sects_per_page - 1)))
			blk_finish_plug(&plug);
#endif
		sb_breadahead(sb, secno + i);
	}
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,38)
	blk_finish_plug(&plug);
#endif

	return 0;
}