/*
* Linux Software RAID (md) topology
* -- this is fallback for old systems where the topology information is not
* exported by sysfs
*
* Copyright (C) 2009 Karel Zak <kzak@redhat.com>
*
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
*
*/
#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "topology.h"
#ifndef MD_MAJOR
#define MD_MAJOR 9
#endif
#ifndef _IOT__IOTBASE_uint32_t
#define _IOT__IOTBASE_uint32_t IOT_SIMPLE(uint32_t)
#endif
#define _IOT_md_array_info _IOT (_IOTS(uint32_t), 18, 0, 0, 0, 0)
#define GET_ARRAY_INFO _IOR (MD_MAJOR, 0x11, struct md_array_info)
struct md_array_info {
/*
* Generic constant information
*/
uint32_t major_version;
uint32_t minor_version;
uint32_t patch_version;
uint32_t ctime;
uint32_t level;
uint32_t size;
uint32_t nr_disks;
uint32_t raid_disks;
uint32_t md_minor;
uint32_t not_persistent;
/*
* Generic state information
*/
uint32_t utime; /* 0 Superblock update time */
uint32_t state; /* 1 State bits (clean, ...) */
uint32_t active_disks; /* 2 Number of currently active disks */
uint32_t working_disks; /* 3 Number of working disks */
uint32_t failed_disks; /* 4 Number of failed disks */
uint32_t spare_disks; /* 5 Number of spare disks */
/*
* Personality information
*/
uint32_t layout; /* 0 the array's physical layout */
uint32_t chunk_size; /* 1 chunk size in bytes */
};
static int is_md_device(dev_t devno)
{
if (major(devno) == MD_MAJOR)
return 1;
return blkid_driver_has_major("md", major(devno));
}
static int probe_md_tp(blkid_probe pr,
const struct blkid_idmag *mag __attribute__((__unused__)))
{
int fd = -1;
dev_t disk = 0;
dev_t devno = blkid_probe_get_devno(pr);
struct md_array_info md;
if (!devno)
goto nothing; /* probably not a block device */
if (!is_md_device(devno))
goto nothing;
if (blkid_devno_to_wholedisk(devno, NULL, 0, &disk))
goto nothing;
if (disk == devno)
fd = pr->fd;
else {
char *diskpath = blkid_devno_to_devname(disk);
if (!diskpath)
goto nothing;
fd = open(diskpath, O_RDONLY|O_CLOEXEC);
free(diskpath);
if (fd == -1)
goto nothing;
}
memset(&md, 0, sizeof(md));
if (ioctl(fd, GET_ARRAY_INFO, &md))
goto nothing;
if (fd >= 0 && fd != pr->fd) {
close(fd);
fd = -1;
}
/*
* Ignore levels we don't want aligned (e.g. linear)
* and deduct disk(s) from stripe width on RAID4/5/6
*/
switch (md.level) {
case 6:
md.raid_disks--;
/* fallthrough */
case 5:
case 4:
md.raid_disks--;
/* fallthrough */
case 1:
case 0:
case 10:
break;
default:
goto nothing;
}
blkid_topology_set_minimum_io_size(pr, md.chunk_size);
blkid_topology_set_optimal_io_size(pr, md.chunk_size * md.raid_disks);
return 0;
nothing:
if (fd >= 0 && fd != pr->fd)
close(fd);
return 1;
}
const struct blkid_idinfo md_tp_idinfo =
{
.name = "md",
.probefunc = probe_md_tp,
.magics = BLKID_NONE_MAGIC
};
