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lvm2/lib/device/dev-md.c
Zdenek Kabelac a481f42630 cov: always initialized values
Make sure values are initialized for all possible paths.
2020-09-01 17:57:50 +02:00

561 lines
13 KiB
C

/*
* Copyright (C) 2004 Luca Berra
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser 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 "lib/misc/lib.h"
#include "lib/device/dev-type.h"
#include "lib/mm/xlate.h"
#include "lib/misc/crc.h"
#ifdef UDEV_SYNC_SUPPORT
#include <libudev.h> /* for MD detection using udev db records */
#include "lib/device/dev-ext-udev-constants.h"
#endif
#ifdef __linux__
/* Lifted from <linux/raid/md_p.h> because of difficulty including it */
#define MD_SB_MAGIC 0xa92b4efc
#define MD_RESERVED_BYTES (64 * 1024ULL)
#define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512)
#define MD_NEW_SIZE_SECTORS(x) (((x) & ~(MD_RESERVED_SECTORS - 1)) \
- MD_RESERVED_SECTORS)
#define MD_MAX_SYSFS_SIZE 64
static int _dev_has_md_magic(struct device *dev, uint64_t sb_offset)
{
uint32_t md_magic;
/* Version 1 is little endian; version 0.90.0 is machine endian */
if (!dev_read_bytes(dev, sb_offset, sizeof(uint32_t), &md_magic))
return_0;
if ((md_magic == MD_SB_MAGIC) ||
((MD_SB_MAGIC != xlate32(MD_SB_MAGIC)) && (md_magic == xlate32(MD_SB_MAGIC))))
return 1;
return 0;
}
#define IMSM_SIGNATURE "Intel Raid ISM Cfg Sig. "
#define IMSM_SIG_LEN (sizeof(IMSM_SIGNATURE) - 1)
static int _dev_has_imsm_magic(struct device *dev, uint64_t devsize_sectors)
{
char imsm_signature[IMSM_SIG_LEN];
uint64_t off = (devsize_sectors * 512) - 1024;
if (!dev_read_bytes(dev, off, IMSM_SIG_LEN, imsm_signature))
return_0;
if (!memcmp(imsm_signature, IMSM_SIGNATURE, IMSM_SIG_LEN))
return 1;
return 0;
}
#define DDF_MAGIC 0xDE11DE11
struct ddf_header {
uint32_t magic;
uint32_t crc;
char guid[24];
char revision[8];
char padding[472];
};
static int _dev_has_ddf_magic(struct device *dev, uint64_t devsize_sectors, uint64_t *sb_offset)
{
struct ddf_header hdr;
uint32_t crc, our_crc;
uint64_t off;
uint64_t devsize_bytes = devsize_sectors * 512;
if (devsize_bytes < 0x30000)
return 0;
/* 512 bytes before the end of device (from libblkid) */
off = ((devsize_bytes / 0x200) - 1) * 0x200;
if (!dev_read_bytes(dev, off, 512, &hdr))
return_0;
if ((hdr.magic == cpu_to_be32(DDF_MAGIC)) ||
(hdr.magic == cpu_to_le32(DDF_MAGIC))) {
crc = hdr.crc;
hdr.crc = 0xffffffff;
our_crc = calc_crc(0, (const uint8_t *)&hdr, 512);
if ((cpu_to_be32(our_crc) == crc) ||
(cpu_to_le32(our_crc) == crc)) {
*sb_offset = off;
return 1;
} else {
log_debug_devs("Found md ddf magic at %llu wrong crc %x disk %x %s",
(unsigned long long)off, our_crc, crc, dev_name(dev));
return 0;
}
}
/* 128KB before the end of device (from libblkid) */
off = ((devsize_bytes / 0x200) - 257) * 0x200;
if (!dev_read_bytes(dev, off, 512, &hdr))
return_0;
if ((hdr.magic == cpu_to_be32(DDF_MAGIC)) ||
(hdr.magic == cpu_to_le32(DDF_MAGIC))) {
crc = hdr.crc;
hdr.crc = 0xffffffff;
our_crc = calc_crc(0, (const uint8_t *)&hdr, 512);
if ((cpu_to_be32(our_crc) == crc) ||
(cpu_to_le32(our_crc) == crc)) {
*sb_offset = off;
return 1;
} else {
log_debug_devs("Found md ddf magic at %llu wrong crc %x disk %x %s",
(unsigned long long)off, our_crc, crc, dev_name(dev));
return 0;
}
}
return 0;
}
/*
* _udev_dev_is_md_component() only works if
* external_device_info_source="udev"
*
* but
*
* udev_dev_is_md_component() in dev-type.c only works if
* obtain_device_list_from_udev=1
*
* and neither of those config setting matches very well
* with what we're doing here.
*/
#ifdef UDEV_SYNC_SUPPORT
static int _udev_dev_is_md_component(struct device *dev)
{
const char *value;
struct dev_ext *ext;
if (!(ext = dev_ext_get(dev)))
return_0;
if (!(value = udev_device_get_property_value((struct udev_device *)ext->handle, DEV_EXT_UDEV_BLKID_TYPE))) {
dev->flags |= DEV_UDEV_INFO_MISSING;
return 0;
}
return !strcmp(value, DEV_EXT_UDEV_BLKID_TYPE_SW_RAID);
}
#else
static int _udev_dev_is_md_component(struct device *dev)
{
dev->flags |= DEV_UDEV_INFO_MISSING;
return 0;
}
#endif
/*
* Returns -1 on error
*/
static int _native_dev_is_md_component(struct device *dev, uint64_t *offset_found, int full)
{
uint64_t size, sb_offset = 0;
int ret;
if (!scan_bcache)
return -EAGAIN;
if (!dev_get_size(dev, &size)) {
stack;
return -1;
}
if (size < MD_RESERVED_SECTORS * 2)
return 0;
/*
* Some md versions locate the magic number at the end of the device.
* Those checks can't be satisfied with the initial scan data, and
* require an extra read i/o at the end of every device. Issuing
* an extra read to every device in every command, just to check for
* the old md format is a bad tradeoff.
*
* When "full" is set, we check a the start and end of the device for
* md magic numbers. When "full" is not set, we only check at the
* start of the device for the magic numbers. We decide for each
* command if it should do a full check (cmd->use_full_md_check),
* and set it for commands that could possibly write to an md dev
* (pvcreate/vgcreate/vgextend).
*/
/*
* md superblock version 1.1 at offset 0 from start
*/
if (_dev_has_md_magic(dev, 0)) {
log_debug_devs("Found md magic number at offset 0 of %s.", dev_name(dev));
ret = 1;
goto out;
}
/*
* md superblock version 1.2 at offset 4KB from start
*/
if (_dev_has_md_magic(dev, 4096)) {
log_debug_devs("Found md magic number at offset 4096 of %s.", dev_name(dev));
ret = 1;
goto out;
}
if (!full) {
ret = 0;
goto out;
}
/*
* Handle superblocks at the end of the device.
*/
/*
* md superblock version 0 at 64KB from end of device
* (after end is aligned to 64KB)
*/
sb_offset = MD_NEW_SIZE_SECTORS(size) << SECTOR_SHIFT;
if (_dev_has_md_magic(dev, sb_offset)) {
log_debug_devs("Found md magic number at offset %llu of %s.", (unsigned long long)sb_offset, dev_name(dev));
ret = 1;
goto out;
}
/*
* md superblock version 1.0 at 8KB from end of device
*/
sb_offset = ((size - 8 * 2) & ~(4 * 2 - 1ULL)) << SECTOR_SHIFT;
if (_dev_has_md_magic(dev, sb_offset)) {
log_debug_devs("Found md magic number at offset %llu of %s.", (unsigned long long)sb_offset, dev_name(dev));
ret = 1;
goto out;
}
/*
* md imsm superblock 1K from end of device
*/
if (_dev_has_imsm_magic(dev, size)) {
log_debug_devs("Found md imsm magic number at offset %llu of %s.", (unsigned long long)sb_offset, dev_name(dev));
sb_offset = 1024;
ret = 1;
goto out;
}
/*
* md ddf superblock 512 bytes from end, or 128KB from end
*/
if (_dev_has_ddf_magic(dev, size, &sb_offset)) {
log_debug_devs("Found md ddf magic number at offset %llu of %s.", (unsigned long long)sb_offset, dev_name(dev));
ret = 1;
goto out;
}
ret = 0;
out:
if (ret && offset_found)
*offset_found = sb_offset;
return ret;
}
int dev_is_md_component(struct device *dev, uint64_t *offset_found, int full)
{
int ret;
/*
* If non-native device status source is selected, use it
* only if offset_found is not requested as this
* information is not in udev db.
*/
if ((dev->ext.src == DEV_EXT_NONE) || offset_found) {
ret = _native_dev_is_md_component(dev, offset_found, full);
if (!full) {
if (!ret || (ret == -EAGAIN)) {
if (udev_dev_is_md_component(dev))
ret = 1;
}
}
if (ret && (ret != -EAGAIN))
dev->flags |= DEV_IS_MD_COMPONENT;
return ret;
}
if (dev->ext.src == DEV_EXT_UDEV) {
ret = _udev_dev_is_md_component(dev);
if (ret && (ret != -EAGAIN))
dev->flags |= DEV_IS_MD_COMPONENT;
return ret;
}
log_error(INTERNAL_ERROR "Missing hook for MD device recognition "
"using external device info source %s", dev_ext_name(dev));
return -1;
}
static int _md_sysfs_attribute_snprintf(char *path, size_t size,
struct dev_types *dt,
struct device *blkdev,
const char *attribute)
{
const char *sysfs_dir = dm_sysfs_dir();
struct stat info;
dev_t dev = blkdev->dev;
int ret = -1;
if (!sysfs_dir || !*sysfs_dir)
return ret;
if (MAJOR(dev) == dt->blkext_major) {
/* lookup parent MD device from blkext partition */
if (!dev_get_primary_dev(dt, blkdev, &dev))
return ret;
}
if (MAJOR(dev) != dt->md_major)
return ret;
ret = dm_snprintf(path, size, "%s/dev/block/%d:%d/md/%s", sysfs_dir,
(int)MAJOR(dev), (int)MINOR(dev), attribute);
if (ret < 0) {
log_error("dm_snprintf md %s failed", attribute);
return ret;
}
if (stat(path, &info) == -1) {
if (errno != ENOENT) {
log_sys_error("stat", path);
return ret;
}
/* old sysfs structure */
ret = dm_snprintf(path, size, "%s/block/md%d/md/%s",
sysfs_dir, (int)MINOR(dev), attribute);
if (ret < 0) {
log_error("dm_snprintf old md %s failed", attribute);
return ret;
}
}
return ret;
}
static int _md_sysfs_attribute_scanf(struct dev_types *dt,
struct device *dev,
const char *attribute_name,
const char *attribute_fmt,
void *attribute_value)
{
char path[PATH_MAX+1], buffer[MD_MAX_SYSFS_SIZE];
FILE *fp;
int ret = 0;
if (_md_sysfs_attribute_snprintf(path, PATH_MAX, dt,
dev, attribute_name) < 0)
return ret;
if (!(fp = fopen(path, "r"))) {
log_debug("_md_sysfs_attribute_scanf fopen failed %s", path);
return ret;
}
if (!fgets(buffer, sizeof(buffer), fp)) {
log_debug("_md_sysfs_attribute_scanf fgets failed %s", path);
goto out;
}
if ((ret = sscanf(buffer, attribute_fmt, attribute_value)) != 1) {
log_error("%s sysfs attr %s not in expected format: %s",
dev_name(dev), attribute_name, buffer);
goto out;
}
out:
if (fclose(fp))
log_sys_error("fclose", path);
return ret;
}
/*
* Retrieve chunk size from md device using sysfs.
*/
static unsigned long _dev_md_chunk_size(struct dev_types *dt, struct device *dev)
{
const char *attribute = "chunk_size";
unsigned long chunk_size_bytes = 0UL;
if (_md_sysfs_attribute_scanf(dt, dev, attribute,
"%lu", &chunk_size_bytes) != 1)
return 0;
log_very_verbose("Device %s %s is %lu bytes.",
dev_name(dev), attribute, chunk_size_bytes);
return chunk_size_bytes >> SECTOR_SHIFT;
}
/*
* Retrieve level from md device using sysfs.
*/
static int _dev_md_level(struct dev_types *dt, struct device *dev)
{
char level_string[MD_MAX_SYSFS_SIZE];
const char *attribute = "level";
int level = -1;
if (_md_sysfs_attribute_scanf(dt, dev, attribute,
"%s", &level_string) != 1)
return -1;
log_very_verbose("Device %s %s is %s.",
dev_name(dev), attribute, level_string);
/* We only care about raid - ignore linear/faulty/multipath etc. */
if (sscanf(level_string, "raid%d", &level) != 1)
return -1;
return level;
}
/*
* Retrieve raid_disks from md device using sysfs.
*/
static int _dev_md_raid_disks(struct dev_types *dt, struct device *dev)
{
const char *attribute = "raid_disks";
int raid_disks = 0;
if (_md_sysfs_attribute_scanf(dt, dev, attribute,
"%d", &raid_disks) != 1)
return 0;
log_very_verbose("Device %s %s is %d.",
dev_name(dev), attribute, raid_disks);
return raid_disks;
}
/*
* Calculate stripe width of md device using its sysfs files.
*/
unsigned long dev_md_stripe_width(struct dev_types *dt, struct device *dev)
{
unsigned long chunk_size_sectors = 0UL;
unsigned long stripe_width_sectors = 0UL;
int level, raid_disks, data_disks;
chunk_size_sectors = _dev_md_chunk_size(dt, dev);
if (!chunk_size_sectors)
return 0;
level = _dev_md_level(dt, dev);
if (level < 0)
return 0;
raid_disks = _dev_md_raid_disks(dt, dev);
if (!raid_disks)
return 0;
/* The raid level governs the number of data disks. */
switch (level) {
case 0:
/* striped md does not have any parity disks */
data_disks = raid_disks;
break;
case 1:
case 10:
/* mirrored md effectively has 1 data disk */
data_disks = 1;
break;
case 4:
case 5:
/* both raid 4 and 5 have a single parity disk */
data_disks = raid_disks - 1;
break;
case 6:
/* raid 6 has 2 parity disks */
data_disks = raid_disks - 2;
break;
default:
log_error("Device %s has an unknown md raid level: %d",
dev_name(dev), level);
return 0;
}
stripe_width_sectors = chunk_size_sectors * data_disks;
log_very_verbose("Device %s stripe-width is %lu bytes.",
dev_name(dev),
stripe_width_sectors << SECTOR_SHIFT);
return stripe_width_sectors;
}
int dev_is_md_with_end_superblock(struct dev_types *dt, struct device *dev)
{
char version_string[MD_MAX_SYSFS_SIZE];
const char *attribute = "metadata_version";
if (MAJOR(dev->dev) != dt->md_major)
return 0;
if (_md_sysfs_attribute_scanf(dt, dev, attribute,
"%s", &version_string) != 1)
return 0;
log_very_verbose("Device %s %s is %s.",
dev_name(dev), attribute, version_string);
if (!strcmp(version_string, "1.0") || !strcmp(version_string, "0.90"))
return 1;
return 0;
}
#else
int dev_is_md_component(struct device *dev __attribute__((unused)),
uint64_t *sb __attribute__((unused)))
{
return 0;
}
unsigned long dev_md_stripe_width(struct dev_types *dt __attribute__((unused)),
struct device *dev __attribute__((unused)))
{
return 0UL;
}
#endif