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linux-sg2042/block/partitions/core.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 1991-1998 Linus Torvalds
* Re-organised Feb 1998 Russell King
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/genhd.h>
#include <linux/vmalloc.h>
#include <linux/blktrace_api.h>
#include <linux/raid/detect.h>
#include "check.h"
static int (*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;
state = kzalloc(sizeof(*state), GFP_KERNEL);
if (!state)
return NULL;
nr = disk_max_parts(hd);
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 block_device *bdev)
{
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->bdev = bdev;
disk_name(hd, 0, state->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)
{
struct hd_struct *p = dev_to_part(dev);
return sprintf(buf, "%d\n", p->partno);
}
static ssize_t part_start_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
}
static ssize_t part_ro_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
return sprintf(buf, "%d\n", p->policy ? 1 : 0);
}
static ssize_t part_alignment_offset_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
}
static ssize_t part_discard_alignment_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
return sprintf(buf, "%u\n", p->discard_alignment);
}
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 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)
{
struct hd_struct *p = dev_to_part(dev);
blk_free_devt(dev->devt);
hd_free_part(p);
kfree(p);
}
static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
{
struct hd_struct *part = dev_to_part(dev);
add_uevent_var(env, "PARTN=%u", part->partno);
if (part->info && part->info->volname[0])
add_uevent_var(env, "PARTNAME=%s", part->info->volname);
return 0;
}
struct device_type part_type = {
.name = "partition",
.groups = part_attr_groups,
.release = part_release,
.uevent = part_uevent,
};
static void hd_struct_free_work(struct work_struct *work)
{
struct hd_struct *part =
container_of(to_rcu_work(work), struct hd_struct, rcu_work);
part->start_sect = 0;
part->nr_sects = 0;
part_stat_set_all(part, 0);
put_device(part_to_dev(part));
}
static void hd_struct_free(struct percpu_ref *ref)
{
struct hd_struct *part = container_of(ref, struct hd_struct, ref);
struct gendisk *disk = part_to_disk(part);
struct disk_part_tbl *ptbl =
rcu_dereference_protected(disk->part_tbl, 1);
rcu_assign_pointer(ptbl->last_lookup, NULL);
put_device(disk_to_dev(disk));
INIT_RCU_WORK(&part->rcu_work, hd_struct_free_work);
queue_rcu_work(system_wq, &part->rcu_work);
}
int hd_ref_init(struct hd_struct *part)
{
if (percpu_ref_init(&part->ref, hd_struct_free, 0, GFP_KERNEL))
return -ENOMEM;
return 0;
}
/*
* Must be called either with bd_mutex held, before a disk can be opened or
* after all disk users are gone.
*/
void delete_partition(struct gendisk *disk, struct hd_struct *part)
{
struct disk_part_tbl *ptbl =
rcu_dereference_protected(disk->part_tbl, 1);
/*
* ->part_tbl is referenced in this part's release handler, so
* we have to hold the disk device
*/
get_device(disk_to_dev(part_to_disk(part)));
rcu_assign_pointer(ptbl->part[part->partno], NULL);
kobject_put(part->holder_dir);
device_del(part_to_dev(part));
/*
* Remove gendisk pointer from idr so that it cannot be looked up
* while RCU period before freeing gendisk is running to prevent
* use-after-free issues. Note that the device number stays
* "in-use" until we really free the gendisk.
*/
blk_invalidate_devt(part_devt(part));
percpu_ref_kill(&part->ref);
}
static ssize_t whole_disk_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return 0;
}
static DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
/*
* Must be called either with bd_mutex held, before a disk can be opened or
* after all disk users are gone.
*/
static struct hd_struct *add_partition(struct gendisk *disk, int partno,
sector_t start, sector_t len, int flags,
struct partition_meta_info *info)
{
struct hd_struct *p;
dev_t devt = MKDEV(0, 0);
struct device *ddev = disk_to_dev(disk);
struct device *pdev;
struct disk_part_tbl *ptbl;
const char *dname;
int err;
/*
* Partitions are not supported on zoned block devices that are used as
* such.
*/
switch (disk->queue->limits.zoned) {
case BLK_ZONED_HM:
pr_warn("%s: partitions not supported on host managed zoned block device\n",
disk->disk_name);
return ERR_PTR(-ENXIO);
case BLK_ZONED_HA:
pr_info("%s: disabling host aware zoned block device support due to partitions\n",
disk->disk_name);
disk->queue->limits.zoned = BLK_ZONED_NONE;
break;
case BLK_ZONED_NONE:
break;
}
err = disk_expand_part_tbl(disk, partno);
if (err)
return ERR_PTR(err);
ptbl = rcu_dereference_protected(disk->part_tbl, 1);
if (ptbl->part[partno])
return ERR_PTR(-EBUSY);
p = kzalloc(sizeof(*p), GFP_KERNEL);
if (!p)
return ERR_PTR(-EBUSY);
p->dkstats = alloc_percpu(struct disk_stats);
if (!p->dkstats) {
err = -ENOMEM;
goto out_free;
}
hd_sects_seq_init(p);
pdev = part_to_dev(p);
p->start_sect = start;
p->alignment_offset =
queue_limit_alignment_offset(&disk->queue->limits, start);
p->discard_alignment =
queue_limit_discard_alignment(&disk->queue->limits, start);
p->nr_sects = len;
p->partno = partno;
p->policy = get_disk_ro(disk);
if (info) {
struct partition_meta_info *pinfo;
pinfo = kzalloc_node(sizeof(*pinfo), GFP_KERNEL, disk->node_id);
if (!pinfo) {
err = -ENOMEM;
goto out_free_stats;
}
memcpy(pinfo, info, sizeof(*info));
p->info = pinfo;
}
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;
err = blk_alloc_devt(p, &devt);
if (err)
goto out_free_info;
pdev->devt = devt;
/* delay uevent until 'holders' subdir is created */
dev_set_uevent_suppress(pdev, 1);
err = device_add(pdev);
if (err)
goto out_put;
err = -ENOMEM;
p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
if (!p->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;
}
err = hd_ref_init(p);
if (err) {
if (flags & ADDPART_FLAG_WHOLEDISK)
goto out_remove_file;
goto out_del;
}
/* everything is up and running, commence */
rcu_assign_pointer(ptbl->part[partno], p);
/* suppress uevent if the disk suppresses it */
if (!dev_get_uevent_suppress(ddev))
kobject_uevent(&pdev->kobj, KOBJ_ADD);
return p;
out_free_info:
kfree(p->info);
out_free_stats:
free_percpu(p->dkstats);
out_free:
kfree(p);
return ERR_PTR(err);
out_remove_file:
device_remove_file(pdev, &dev_attr_whole_disk);
out_del:
kobject_put(p->holder_dir);
device_del(pdev);
out_put:
put_device(pdev);
return ERR_PTR(err);
}
static bool partition_overlaps(struct gendisk *disk, sector_t start,
sector_t length, int skip_partno)
{
struct disk_part_iter piter;
struct hd_struct *part;
bool overlap = false;
disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
while ((part = disk_part_iter_next(&piter))) {
if (part->partno == skip_partno ||
start >= part->start_sect + part->nr_sects ||
start + length <= part->start_sect)
continue;
overlap = true;
break;
}
disk_part_iter_exit(&piter);
return overlap;
}
int bdev_add_partition(struct block_device *bdev, int partno,
sector_t start, sector_t length)
{
struct hd_struct *part;
mutex_lock(&bdev->bd_mutex);
if (partition_overlaps(bdev->bd_disk, start, length, -1)) {
mutex_unlock(&bdev->bd_mutex);
return -EBUSY;
}
part = add_partition(bdev->bd_disk, partno, start, length,
ADDPART_FLAG_NONE, NULL);
mutex_unlock(&bdev->bd_mutex);
return PTR_ERR_OR_ZERO(part);
}
int bdev_del_partition(struct block_device *bdev, int partno)
{
struct block_device *bdevp;
struct hd_struct *part;
int ret = 0;
part = disk_get_part(bdev->bd_disk, partno);
if (!part)
return -ENXIO;
ret = -ENOMEM;
bdevp = bdget(part_devt(part));
if (!bdevp)
goto out_put_part;
mutex_lock(&bdevp->bd_mutex);
ret = -EBUSY;
if (bdevp->bd_openers)
goto out_unlock;
sync_blockdev(bdevp);
invalidate_bdev(bdevp);
mutex_lock_nested(&bdev->bd_mutex, 1);
delete_partition(bdev->bd_disk, part);
mutex_unlock(&bdev->bd_mutex);
ret = 0;
out_unlock:
mutex_unlock(&bdevp->bd_mutex);
bdput(bdevp);
out_put_part:
disk_put_part(part);
return ret;
}
int bdev_resize_partition(struct block_device *bdev, int partno,
sector_t start, sector_t length)
{
struct block_device *bdevp;
struct hd_struct *part;
int ret = 0;
part = disk_get_part(bdev->bd_disk, partno);
if (!part)
return -ENXIO;
ret = -ENOMEM;
bdevp = bdget(part_devt(part));
if (!bdevp)
goto out_put_part;
mutex_lock(&bdevp->bd_mutex);
mutex_lock_nested(&bdev->bd_mutex, 1);
ret = -EINVAL;
if (start != part->start_sect)
goto out_unlock;
ret = -EBUSY;
if (partition_overlaps(bdev->bd_disk, start, length, partno))
goto out_unlock;
part_nr_sects_write(part, (sector_t)length);
i_size_write(bdevp->bd_inode, length << SECTOR_SHIFT);
ret = 0;
out_unlock:
mutex_unlock(&bdevp->bd_mutex);
mutex_unlock(&bdev->bd_mutex);
bdput(bdevp);
out_put_part:
disk_put_part(part);
return ret;
}
static bool disk_unlock_native_capacity(struct gendisk *disk)
{
const struct block_device_operations *bdops = disk->fops;
if (bdops->unlock_native_capacity &&
!(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
printk(KERN_CONT "enabling native capacity\n");
bdops->unlock_native_capacity(disk);
disk->flags |= GENHD_FL_NATIVE_CAPACITY;
return true;
} else {
printk(KERN_CONT "truncated\n");
return false;
}
}
int blk_drop_partitions(struct block_device *bdev)
{
struct disk_part_iter piter;
struct hd_struct *part;
if (!disk_part_scan_enabled(bdev->bd_disk))
return 0;
if (bdev->bd_part_count)
return -EBUSY;
sync_blockdev(bdev);
invalidate_bdev(bdev);
disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY);
while ((part = disk_part_iter_next(&piter)))
delete_partition(bdev->bd_disk, part);
disk_part_iter_exit(&piter);
return 0;
}
#ifdef CONFIG_S390
/* for historic reasons in the DASD driver */
EXPORT_SYMBOL_GPL(blk_drop_partitions);
#endif
static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
struct parsed_partitions *state, int p)
{
sector_t size = state->parts[p].size;
sector_t from = state->parts[p].from;
struct hd_struct *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) && PTR_ERR(part) != -ENXIO) {
printk(KERN_ERR " %s: p%d could not be added: %ld\n",
disk->disk_name, p, -PTR_ERR(part));
return true;
}
if (IS_BUILTIN(CONFIG_BLK_DEV_MD) &&
(state->parts[p].flags & ADDPART_FLAG_RAID))
md_autodetect_dev(part_to_dev(part)->devt);
return true;
}
int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
{
struct parsed_partitions *state;
int ret = -EAGAIN, p, highest;
if (!disk_part_scan_enabled(disk))
return 0;
state = check_partition(disk, bdev);
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 (disk->queue->limits.zoned == BLK_ZONED_HM) {
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);
/*
* Detect the highest partition number and preallocate disk->part_tbl.
* This is an optimization and not strictly necessary.
*/
for (p = 1, highest = 0; p < state->limit; p++)
if (state->parts[p].size)
highest = p;
disk_expand_part_tbl(disk, highest);
for (p = 1; p < state->limit; p++)
if (!blk_add_partition(disk, bdev, state, p))
goto out_free_state;
ret = 0;
out_free_state:
free_partitions(state);
return ret;
}
void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
{
struct address_space *mapping = state->bdev->bd_inode->i_mapping;
struct page *page;
if (n >= get_capacity(state->bdev->bd_disk)) {
state->access_beyond_eod = true;
return NULL;
}
page = read_mapping_page(mapping,
(pgoff_t)(n >> (PAGE_SHIFT - 9)), NULL);
if (IS_ERR(page))
goto out;
if (PageError(page))
goto out_put_page;
p->v = page;
return (unsigned char *)page_address(page) +
((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << SECTOR_SHIFT);
out_put_page:
put_page(page);
out:
p->v = NULL;
return NULL;
}
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