// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 1991-1998 Linus Torvalds
* Re-organised Feb 1998 Russell King
* Copyright (C) 2020 Christoph Hellwig
*/
#include <linux/fs.h>
#include <linux/major.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/vmalloc.h>
#include <linux/raid/detect.h>
#include "check.h"
static int (*const check_part[])(struct parsed_partitions *) = {
/*
* Probe partition formats with tables at disk address 0
* that also have an ADFS boot block at 0xdc0.
*/
#ifdef CONFIG_ACORN_PARTITION_ICS
adfspart_check_ICS,
#endif
#ifdef CONFIG_ACORN_PARTITION_POWERTEC
adfspart_check_POWERTEC,
#endif
#ifdef CONFIG_ACORN_PARTITION_EESOX
adfspart_check_EESOX,
#endif
/*
* Now move on to formats that only have partition info at
* disk address 0xdc0. Since these may also have stale
* PC/BIOS partition tables, they need to come before
* the msdos entry.
*/
#ifdef CONFIG_ACORN_PARTITION_CUMANA
adfspart_check_CUMANA,
#endif
#ifdef CONFIG_ACORN_PARTITION_ADFS
adfspart_check_ADFS,
#endif
#ifdef CONFIG_CMDLINE_PARTITION
cmdline_partition,
#endif
#ifdef CONFIG_EFI_PARTITION
efi_partition, /* this must come before msdos */
#endif
#ifdef CONFIG_SGI_PARTITION
sgi_partition,
#endif
#ifdef CONFIG_LDM_PARTITION
ldm_partition, /* this must come before msdos */
#endif
#ifdef CONFIG_MSDOS_PARTITION
msdos_partition,
#endif
#ifdef CONFIG_OSF_PARTITION
osf_partition,
#endif
#ifdef CONFIG_SUN_PARTITION
sun_partition,
#endif
#ifdef CONFIG_AMIGA_PARTITION
amiga_partition,
#endif
#ifdef CONFIG_ATARI_PARTITION
atari_partition,
#endif
#ifdef CONFIG_MAC_PARTITION
mac_partition,
#endif
#ifdef CONFIG_ULTRIX_PARTITION
ultrix_partition,
#endif
#ifdef CONFIG_IBM_PARTITION
ibm_partition,
#endif
#ifdef CONFIG_KARMA_PARTITION
karma_partition,
#endif
#ifdef CONFIG_SYSV68_PARTITION
sysv68_partition,
#endif
NULL
};
static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
{
struct parsed_partitions *state;
int nr = DISK_MAX_PARTS;
state = kzalloc(sizeof(*state), GFP_KERNEL);
if (!state)
return NULL;
state->parts = vzalloc(array_size(nr, sizeof(state->parts[0])));
if (!state->parts) {
kfree(state);
return NULL;
}
state->limit = nr;
return state;
}
static void free_partitions(struct parsed_partitions *state)
{
vfree(state->parts);
kfree(state);
}
static struct parsed_partitions *check_partition(struct gendisk *hd)
{
struct parsed_partitions *state;
int i, res, err;
state = allocate_partitions(hd);
if (!state)
return NULL;
state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
if (!state->pp_buf) {
free_partitions(state);
return NULL;
}
state->pp_buf[0] = '\0';
state->disk = hd;
snprintf(state->name, BDEVNAME_SIZE, "%s", hd->disk_name);
snprintf(state->pp_buf, PAGE_SIZE, " %s:", state->name);
if (isdigit(state->name[strlen(state->name)-1]))
sprintf(state->name, "p");
i = res = err = 0;
while (!res && check_part[i]) {
memset(state->parts, 0, state->limit * sizeof(state->parts[0]));
res = check_part[i++](state);
if (res < 0) {
/*
* We have hit an I/O error which we don't report now.
* But record it, and let the others do their job.
*/
err = res;
res = 0;
}
}
if (res > 0) {
printk(KERN_INFO "%s", state->pp_buf);
free_page((unsigned long)state->pp_buf);
return state;
}
if (state->access_beyond_eod)
err = -ENOSPC;
/*
* The partition is unrecognized. So report I/O errors if there were any
*/
if (err)
res = err;
if (res) {
strlcat(state->pp_buf,
" unable to read partition table\n", PAGE_SIZE);
printk(KERN_INFO "%s", state->pp_buf);
}
free_page((unsigned long)state->pp_buf);
free_partitions(state);
return ERR_PTR(res);
}
static ssize_t part_partition_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", bdev_partno(dev_to_bdev(dev)));
}
static ssize_t part_start_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%llu\n", dev_to_bdev(dev)->bd_start_sect);
}
static ssize_t part_ro_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", bdev_read_only(dev_to_bdev(dev)));
}
static ssize_t part_alignment_offset_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%u\n", bdev_alignment_offset(dev_to_bdev(dev)));
}
static ssize_t part_discard_alignment_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%u\n", bdev_discard_alignment(dev_to_bdev(dev)));
}
static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
static DEVICE_ATTR(start, 0444, part_start_show, NULL);
static DEVICE_ATTR(size, 0444, part_size_show, NULL);
static DEVICE_ATTR(ro, 0444, part_ro_show, NULL);
static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL);
static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL);
static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
#ifdef CONFIG_FAIL_MAKE_REQUEST
static struct device_attribute dev_attr_fail =
__ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
#endif
static struct attribute *part_attrs[] = {
&dev_attr_partition.attr,
&dev_attr_start.attr,
&dev_attr_size.attr,
&dev_attr_ro.attr,
&dev_attr_alignment_offset.attr,
&dev_attr_discard_alignment.attr,
&dev_attr_stat.attr,
&dev_attr_inflight.attr,
#ifdef CONFIG_FAIL_MAKE_REQUEST
&dev_attr_fail.attr,
#endif
NULL
};
static const struct attribute_group part_attr_group = {
.attrs = part_attrs,
};
static const struct attribute_group *part_attr_groups[] = {
&part_attr_group,
#ifdef CONFIG_BLK_DEV_IO_TRACE
&blk_trace_attr_group,
#endif
NULL
};
static void part_release(struct device *dev)
{
put_disk(dev_to_bdev(dev)->bd_disk);
bdev_drop(dev_to_bdev(dev));
}
static int part_uevent(const struct device *dev, struct kobj_uevent_env *env)
{
const struct block_device *part = dev_to_bdev(dev);
add_uevent_var(env, "PARTN=%u", bdev_partno(part));
if (part->bd_meta_info && part->bd_meta_info->volname[0])
add_uevent_var(env, "PARTNAME=%s", part->bd_meta_info->volname);
return 0;
}
const struct device_type part_type = {
.name = "partition",
.groups = part_attr_groups,
.release = part_release,
.uevent = part_uevent,
};
void drop_partition(struct block_device *part)
{
lockdep_assert_held(&part->bd_disk->open_mutex);
xa_erase(&part->bd_disk->part_tbl, bdev_partno(part));
kobject_put(part->bd_holder_dir);
device_del(&part->bd_device);
put_device(&part->bd_device);
}
static ssize_t whole_disk_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return 0;
}
static const DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
/*
* Must be called either with open_mutex held, before a disk can be opened or
* after all disk users are gone.
*/
static struct block_device *add_partition(struct gendisk *disk, int partno,
sector_t start, sector_t len, int flags,
struct partition_meta_info *info)
{
dev_t devt = MKDEV(0, 0);
struct device *ddev = disk_to_dev(disk);
struct device *pdev;
struct block_device *bdev;
const char *dname;
int err;
lockdep_assert_held(&disk->open_mutex);
if (partno >= DISK_MAX_PARTS)
return ERR_PTR(-EINVAL);
/*
* Partitions are not supported on zoned block devices that are used as
* such.
*/
if (bdev_is_zoned(disk->part0)) {
pr_warn("%s: partitions not supported on host managed zoned block device\n",
disk->disk_name);
return ERR_PTR(-ENXIO);
}
if (xa_load(&disk->part_tbl, partno))
return ERR_PTR(-EBUSY);
/* ensure we always have a reference to the whole disk */
get_device(disk_to_dev(disk));
err = -ENOMEM;
bdev = bdev_alloc(disk, partno);
if (!bdev)
goto out_put_disk;
bdev->bd_start_sect = start;
bdev_set_nr_sectors(bdev, len);
pdev = &bdev->bd_device;
dname = dev_name(ddev);
if (isdigit(dname[strlen(dname) - 1]))
dev_set_name(pdev, "%sp%d", dname, partno);
else
dev_set_name(pdev, "%s%d", dname, partno);
device_initialize(pdev);
pdev->class = &block_class;
pdev->type = &part_type;
pdev->parent = ddev;
/* in consecutive minor range? */
if (bdev_partno(bdev) < disk->minors) {
devt = MKDEV(disk->major, disk->first_minor + bdev_partno(bdev));
} else {
err = blk_alloc_ext_minor();
if (err < 0)
goto out_put;
devt = MKDEV(BLOCK_EXT_MAJOR, err);
}
pdev->devt = devt;
if (info) {
err = -ENOMEM;
bdev->bd_meta_info = kmemdup(info, sizeof(*info), GFP_KERNEL);
if (!bdev->bd_meta_info)
goto out_put;
}
/* delay uevent until 'holders' subdir is created */
dev_set_uevent_suppress(pdev, 1);
err = device_add(pdev);
if (err)
goto out_put;
err = -ENOMEM;
bdev->bd_holder_dir = kobject_create_and_add("holders", &pdev->kobj);
if (!bdev->bd_holder_dir)
goto out_del;
dev_set_uevent_suppress(pdev, 0);
if (flags & ADDPART_FLAG_WHOLEDISK) {
err = device_create_file(pdev, &dev_attr_whole_disk);
if (err)
goto out_del;
}
/* everything is up and running, commence */
err = xa_insert(&disk->part_tbl, partno, bdev, GFP_KERNEL);
if (err)
goto out_del;
bdev_add(bdev, devt);
/* suppress uevent if the disk suppresses it */
if (!dev_get_uevent_suppress(ddev))
kobject_uevent(&pdev->kobj, KOBJ_ADD);
return bdev;
out_del:
kobject_put(bdev->bd_holder_dir);
device_del(pdev);
out_put:
put_device(pdev);
return ERR_PTR(err);
out_put_disk:
put_disk(disk);
return ERR_PTR(err);
}
static bool partition_overlaps(struct gendisk *disk, sector_t start,
sector_t length, int skip_partno)
{
struct block_device *part;
bool overlap = false;
unsigned long idx;
rcu_read_lock();
xa_for_each_start(&disk->part_tbl, idx, part, 1) {
if (bdev_partno(part) != skip_partno &&
start < part->bd_start_sect + bdev_nr_sectors(part) &&
start + length > part->bd_start_sect) {
overlap = true;
break;
}
}
rcu_read_unlock();
return overlap;
}
int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
sector_t length)
{
struct block_device *part;
int ret;
mutex_lock(&disk->open_mutex);
if (!disk_live(disk)) {
ret = -ENXIO;
goto out;
}
if (disk->flags & GENHD_FL_NO_PART) {
ret = -EINVAL;
goto out;
}
if (partition_overlaps(disk, start, length, -1)) {
ret = -EBUSY;
goto out;
}
part = add_partition(disk, partno, start, length,
ADDPART_FLAG_NONE, NULL);
ret = PTR_ERR_OR_ZERO(part);
out:
mutex_unlock(&disk->open_mutex);
return ret;
}
int bdev_del_partition(struct gendisk *disk, int partno)
{
struct block_device *part = NULL;
int ret = -ENXIO;
mutex_lock(&disk->open_mutex);
part = xa_load(&disk->part_tbl, partno);
if (!part)
goto out_unlock;
ret = -EBUSY;
if (atomic_read(&part->bd_openers))
goto out_unlock;
/*
* We verified that @part->bd_openers is zero above and so
* @part->bd_holder{_ops} can't be set. And since we hold
* @disk->open_mutex the device can't be claimed by anyone.
*
* So no need to call @part->bd_holder_ops->mark_dead() here.
* Just delete the partition and invalidate it.
*/
bdev_unhash(part);
invalidate_bdev(part);
drop_partition(part);
ret = 0;
out_unlock:
mutex_unlock(&disk->open_mutex);
return ret;
}
int bdev_resize_partition(struct gendisk *disk, int partno, sector_t start,
sector_t length)
{
struct block_device *part = NULL;
int ret = -ENXIO;
mutex_lock(&disk->open_mutex);
part = xa_load(&disk->part_tbl, partno);
if (!part)
goto out_unlock;
ret = -EINVAL;
if (start != part->bd_start_sect)
goto out_unlock;
ret = -EBUSY;
if (partition_overlaps(disk, start, length, partno))
goto out_unlock;
bdev_set_nr_sectors(part, length);
ret = 0;
out_unlock:
mutex_unlock(&disk->open_mutex);
return ret;
}
static bool disk_unlock_native_capacity(struct gendisk *disk)
{
if (!disk->fops->unlock_native_capacity ||
test_and_set_bit(GD_NATIVE_CAPACITY, &disk->state)) {
printk(KERN_CONT "truncated\n");
return false;
}
printk(KERN_CONT "enabling native capacity\n");
disk->fops->unlock_native_capacity(disk);
return true;
}
static bool blk_add_partition(struct gendisk *disk,
struct parsed_partitions *state, int p)
{
sector_t size = state->parts[p].size;
sector_t from = state->parts[p].from;
struct block_device *part;
if (!size)
return true;
if (from >= get_capacity(disk)) {
printk(KERN_WARNING
"%s: p%d start %llu is beyond EOD, ",
disk->disk_name, p, (unsigned long long) from);
if (disk_unlock_native_capacity(disk))
return false;
return true;
}
if (from + size > get_capacity(disk)) {
printk(KERN_WARNING
"%s: p%d size %llu extends beyond EOD, ",
disk->disk_name, p, (unsigned long long) size);
if (disk_unlock_native_capacity(disk))
return false;
/*
* We can not ignore partitions of broken tables created by for
* example camera firmware, but we limit them to the end of the
* disk to avoid creating invalid block devices.
*/
size = get_capacity(disk) - from;
}
part = add_partition(disk, p, from, size, state->parts[p].flags,
&state->parts[p].info);
if (IS_ERR(part)) {
if (PTR_ERR(part) != -ENXIO) {
printk(KERN_ERR " %s: p%d could not be added: %pe\n",
disk->disk_name, p, part);
}
return true;
}
if (IS_BUILTIN(CONFIG_BLK_DEV_MD) &&
(state->parts[p].flags & ADDPART_FLAG_RAID))
md_autodetect_dev(part->bd_dev);
return true;
}
static int blk_add_partitions(struct gendisk *disk)
{
struct parsed_partitions *state;
int ret = -EAGAIN, p;
if (!disk_has_partscan(disk))
return 0;
state = check_partition(disk);
if (!state)
return 0;
if (IS_ERR(state)) {
/*
* I/O error reading the partition table. If we tried to read
* beyond EOD, retry after unlocking the native capacity.
*/
if (PTR_ERR(state) == -ENOSPC) {
printk(KERN_WARNING "%s: partition table beyond EOD, ",
disk->disk_name);
if (disk_unlock_native_capacity(disk))
return -EAGAIN;
}
return -EIO;
}
/*
* Partitions are not supported on host managed zoned block devices.
*/
if (bdev_is_zoned(disk->part0)) {
pr_warn("%s: ignoring partition table on host managed zoned block device\n",
disk->disk_name);
ret = 0;
goto out_free_state;
}
/*
* If we read beyond EOD, try unlocking native capacity even if the
* partition table was successfully read as we could be missing some
* partitions.
*/
if (state->access_beyond_eod) {
printk(KERN_WARNING
"%s: partition table partially beyond EOD, ",
disk->disk_name);
if (disk_unlock_native_capacity(disk))
goto out_free_state;
}
/* tell userspace that the media / partition table may have changed */
kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
for (p = 1; p < state->limit; p++)
if (!blk_add_partition(disk, state, p))
goto out_free_state;
ret = 0;
out_free_state:
free_partitions(state);
return ret;
}
int bdev_disk_changed(struct gendisk *disk, bool invalidate)
{
struct block_device *part;
unsigned long idx;
int ret = 0;
lockdep_assert_held(&disk->open_mutex);
if (!disk_live(disk))
return -ENXIO;
rescan:
if (disk->open_partitions)
return -EBUSY;
sync_blockdev(disk->part0);
invalidate_bdev(disk->part0);
xa_for_each_start(&disk->part_tbl, idx, part, 1) {
/*
* Remove the block device from the inode hash, so that
* it cannot be looked up any more even when openers
* still hold references.
*/
bdev_unhash(part);
/*
* If @disk->open_partitions isn't elevated but there's
* still an active holder of that block device things
* are broken.
*/
WARN_ON_ONCE(atomic_read(&part->bd_openers));
invalidate_bdev(part);
drop_partition(part);
}
clear_bit(GD_NEED_PART_SCAN, &disk->state);
/*
* Historically we only set the capacity to zero for devices that
* support partitions (independ of actually having partitions created).
* Doing that is rather inconsistent, but changing it broke legacy
* udisks polling for legacy ide-cdrom devices. Use the crude check
* below to get the sane behavior for most device while not breaking
* userspace for this particular setup.
*/
if (invalidate) {
if (!(disk->flags & GENHD_FL_NO_PART) ||
!(disk->flags & GENHD_FL_REMOVABLE))
set_capacity(disk, 0);
}
if (get_capacity(disk)) {
ret = blk_add_partitions(disk);
if (ret == -EAGAIN)
goto rescan;
} else if (invalidate) {
/*
* Tell userspace that the media / partition table may have
* changed.
*/
kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
}
return ret;
}
/*
* Only exported for loop and dasd for historic reasons. Don't use in new
* code!
*/
EXPORT_SYMBOL_GPL(bdev_disk_changed);
void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
{
struct address_space *mapping = state->disk->part0->bd_mapping;
struct folio *folio;
if (n >= get_capacity(state->disk)) {
state->access_beyond_eod = true;
goto out;
}
folio = read_mapping_folio(mapping, n >> PAGE_SECTORS_SHIFT, NULL);
if (IS_ERR(folio))
goto out;
p->v = folio;
return folio_address(folio) + offset_in_folio(folio, n * SECTOR_SIZE);
out:
p->v = NULL;
return NULL;
}
Codebase Browser
linux