freebsd-skq/sys/boot/common/disk.h
ae 2ad040bf3f Add the flags parameter to the disk_open() function and DISK_F_NOCACHE
flag, that disables the caching of partition tables metadata.
Use this flag for floppies in the libi386/biosdisk driver.
2012-10-21 12:14:58 +00:00

109 lines
3.6 KiB
C

/*-
* Copyright (c) 2011 Google, Inc.
* 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.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 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.
*
* $FreeBSD$
*/
/*
* Device descriptor for partitioned disks. To use, set the
* d_slice and d_partition variables as follows:
*
* Whole disk access:
*
* d_slice = -1
* d_partition = -1
*
* Whole MBR slice:
*
* d_slice = MBR slice number (typically 1..4)
* d_partition = -1
*
* BSD disklabel partition within an MBR slice:
*
* d_slice = MBR slice number (typically 1..4)
* d_partition = disklabel partition (typically 0..7)
*
* BSD disklabel partition on the true dedicated disk:
*
* d_slice = -1
* d_partition = disklabel partition (typically 0..7)
*
* GPT partition:
*
* d_slice = GPT partition number (typically 1..N)
* d_partition = 255
*
* For both MBR and GPT, to automatically find the 'best' slice or partition,
* set d_slice to zero. This uses the partition type to decide which partition
* to use according to the following list of preferences:
*
* FreeBSD (active)
* FreeBSD (inactive)
* Linux (active)
* Linux (inactive)
* DOS/Windows (active)
* DOS/Windows (inactive)
*
* Active MBR slices (marked as bootable) are preferred over inactive. GPT
* doesn't have the concept of active/inactive partitions. In both MBR and GPT,
* if there are multiple slices/partitions of a given type, the first one
* is chosen.
*
* The low-level disk device will typically call slice_open() from its open
* method to interpret the disk partition tables according to the rules above.
* This will initialize d_offset to the block offset of the start of the
* selected partition - this offset should be added to the offset passed to
* the device's strategy method.
*/
struct disk_devdesc
{
struct devsw *d_dev;
int d_type;
int d_unit;
void *d_opendata;
int d_slice;
int d_partition;
off_t d_offset;
};
/*
* Parse disk metadata and initialise dev->d_offset.
*/
extern int disk_open(struct disk_devdesc *dev, off_t mediasize,
u_int sectorsize, u_int flags);
#define DISK_F_NOCACHE 0x0001 /* Do not use metadata caching */
extern int disk_close(struct disk_devdesc *dev);
extern void disk_cleanup(const struct devsw *d_dev);
/*
* Print information about slices on a disk.
*/
extern void disk_print(struct disk_devdesc *dev, char *prefix, int verbose);
extern char* disk_fmtdev(struct disk_devdesc *dev);
extern int disk_parsedev(struct disk_devdesc *dev, const char *devspec,
const char **path);