btrfs-progs/common/device-utils.c
David Sterba ccbea0977b btrfs-progs: utils: split device handling functions to own file
Helpers that read size, do zeoring, trim or prepare/finalize the device.

Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-04 02:06:34 +02:00

255 lines
5.4 KiB
C

/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* 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., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/statfs.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <blkid/blkid.h>
#include "kernel-lib/sizes.h"
#include "disk-io.h"
#include "common/device-utils.h"
#include "common/internal.h"
#include "common/messages.h"
#include "common/utils.h"
#ifndef BLKDISCARD
#define BLKDISCARD _IO(0x12,119)
#endif
/*
* Discard the given range in one go
*/
static int discard_range(int fd, u64 start, u64 len)
{
u64 range[2] = { start, len };
if (ioctl(fd, BLKDISCARD, &range) < 0)
return errno;
return 0;
}
/*
* Discard blocks in the given range in 1G chunks, the process is interruptible
*/
static int discard_blocks(int fd, u64 start, u64 len)
{
while (len > 0) {
/* 1G granularity */
u64 chunk_size = min_t(u64, len, SZ_1G);
int ret;
ret = discard_range(fd, start, chunk_size);
if (ret)
return ret;
len -= chunk_size;
start += chunk_size;
}
return 0;
}
static int zero_blocks(int fd, off_t start, size_t len)
{
char *buf = malloc(len);
int ret = 0;
ssize_t written;
if (!buf)
return -ENOMEM;
memset(buf, 0, len);
written = pwrite(fd, buf, len, start);
if (written != len)
ret = -EIO;
free(buf);
return ret;
}
#define ZERO_DEV_BYTES SZ_2M
/* don't write outside the device by clamping the region to the device size */
static int zero_dev_clamped(int fd, off_t start, ssize_t len, u64 dev_size)
{
off_t end = max(start, start + len);
#ifdef __sparc__
/* and don't overwrite the disk labels on sparc */
start = max(start, 1024);
end = max(end, 1024);
#endif
start = min_t(u64, start, dev_size);
end = min_t(u64, end, dev_size);
return zero_blocks(fd, start, end - start);
}
static int btrfs_wipe_existing_sb(int fd)
{
const char *off = NULL;
size_t len = 0;
loff_t offset;
char buf[BUFSIZ];
int ret = 0;
blkid_probe pr = NULL;
pr = blkid_new_probe();
if (!pr)
return -1;
if (blkid_probe_set_device(pr, fd, 0, 0)) {
ret = -1;
goto out;
}
ret = blkid_probe_lookup_value(pr, "SBMAGIC_OFFSET", &off, NULL);
if (!ret)
ret = blkid_probe_lookup_value(pr, "SBMAGIC", NULL, &len);
if (ret || len == 0 || off == NULL) {
/*
* If lookup fails, the probe did not find any values, eg. for
* a file image or a loop device. Soft error.
*/
ret = 1;
goto out;
}
offset = strtoll(off, NULL, 10);
if (len > sizeof(buf))
len = sizeof(buf);
memset(buf, 0, len);
ret = pwrite(fd, buf, len, offset);
if (ret < 0) {
error("cannot wipe existing superblock: %m");
ret = -1;
} else if (ret != len) {
error("cannot wipe existing superblock: wrote %d of %zd", ret, len);
ret = -1;
}
fsync(fd);
out:
blkid_free_probe(pr);
return ret;
}
int btrfs_prepare_device(int fd, const char *file, u64 *block_count_ret,
u64 max_block_count, unsigned opflags)
{
u64 block_count;
struct stat st;
int i, ret;
ret = fstat(fd, &st);
if (ret < 0) {
error("unable to stat %s: %m", file);
return 1;
}
block_count = btrfs_device_size(fd, &st);
if (block_count == 0) {
error("unable to determine size of %s", file);
return 1;
}
if (max_block_count)
block_count = min(block_count, max_block_count);
if (opflags & PREP_DEVICE_DISCARD) {
/*
* We intentionally ignore errors from the discard ioctl. It
* is not necessary for the mkfs functionality but just an
* optimization.
*/
if (discard_range(fd, 0, 0) == 0) {
if (opflags & PREP_DEVICE_VERBOSE)
printf("Performing full device TRIM %s (%s) ...\n",
file, pretty_size(block_count));
discard_blocks(fd, 0, block_count);
}
}
ret = zero_dev_clamped(fd, 0, ZERO_DEV_BYTES, block_count);
for (i = 0 ; !ret && i < BTRFS_SUPER_MIRROR_MAX; i++)
ret = zero_dev_clamped(fd, btrfs_sb_offset(i),
BTRFS_SUPER_INFO_SIZE, block_count);
if (!ret && (opflags & PREP_DEVICE_ZERO_END))
ret = zero_dev_clamped(fd, block_count - ZERO_DEV_BYTES,
ZERO_DEV_BYTES, block_count);
if (ret < 0) {
errno = -ret;
error("failed to zero device '%s': %m", file);
return 1;
}
ret = btrfs_wipe_existing_sb(fd);
if (ret < 0) {
error("cannot wipe superblocks on %s", file);
return 1;
}
*block_count_ret = block_count;
return 0;
}
u64 btrfs_device_size(int fd, struct stat *st)
{
u64 size;
if (S_ISREG(st->st_mode)) {
return st->st_size;
}
if (!S_ISBLK(st->st_mode)) {
return 0;
}
if (ioctl(fd, BLKGETSIZE64, &size) >= 0) {
return size;
}
return 0;
}
u64 disk_size(const char *path)
{
struct statfs sfs;
if (statfs(path, &sfs) < 0)
return 0;
else
return sfs.f_bsize * sfs.f_blocks;
}
u64 get_partition_size(const char *dev)
{
u64 result;
int fd = open(dev, O_RDONLY);
if (fd < 0)
return 0;
if (ioctl(fd, BLKGETSIZE64, &result) < 0) {
close(fd);
return 0;
}
close(fd);
return result;
}