1 files changed, 731 insertions, 0 deletions

diff --git a/block/partitions/core.c b/block/partitions/core.c
new file mode 100644
index 000000000..3927f4283
--- /dev/null
+++ b/block/partitions/core.c
@@ -0,0 +1,731 @@
+// 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 (*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 void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors)
+{
+	spin_lock(&bdev->bd_size_lock);
+	i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
+	bdev->bd_nr_sectors = sectors;
+	spin_unlock(&bdev->bd_size_lock);
+}
+
+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", dev_to_bdev(dev)->bd_partno);
+}
+
+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 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);
+	iput(dev_to_bdev(dev)->bd_inode);
+}
+
+static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct block_device *part = dev_to_bdev(dev);
+
+	add_uevent_var(env, "PARTN=%u", part->bd_partno);
+	if (part->bd_meta_info && part->bd_meta_info->volname[0])
+		add_uevent_var(env, "PARTNAME=%s", part->bd_meta_info->volname);
+	return 0;
+}
+
+struct device_type part_type = {
+	.name		= "partition",
+	.groups		= part_attr_groups,
+	.release	= part_release,
+	.uevent		= part_uevent,
+};
+
+static void delete_partition(struct block_device *part)
+{
+	lockdep_assert_held(&part->bd_disk->open_mutex);
+
+	fsync_bdev(part);
+	__invalidate_device(part, true);
+
+	xa_erase(&part->bd_disk->part_tbl, part->bd_partno);
+	kobject_put(part->bd_holder_dir);
+	device_del(&part->bd_device);
+
+	/*
+	 * Remove the block device from the inode hash, so that it cannot be
+	 * looked up any more even when openers still hold references.
+	 */
+	remove_inode_hash(part->bd_inode);
+
+	put_device(&part->bd_device);
+}
+
+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 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.
+	 */
+	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_set_zoned(disk, BLK_ZONED_NONE);
+		break;
+	case BLK_ZONED_NONE:
+		break;
+	}
+
+	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->bd_partno < disk->minors) {
+		devt = MKDEV(disk->major, disk->first_minor + bdev->bd_partno);
+	} 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 (part->bd_partno != 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;
+
+	delete_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;
+}
+
+void blk_drop_partitions(struct gendisk *disk)
+{
+	struct block_device *part;
+	unsigned long idx;
+
+	lockdep_assert_held(&disk->open_mutex);
+
+	xa_for_each_start(&disk->part_tbl, idx, part, 1)
+		delete_partition(part);
+}
+
+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) && 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->bd_dev);
+
+	return true;
+}
+
+static int blk_add_partitions(struct gendisk *disk)
+{
+	struct parsed_partitions *state;
+	int ret = -EAGAIN, p;
+
+	if (disk->flags & GENHD_FL_NO_PART)
+		return 0;
+
+	if (test_bit(GD_SUPPRESS_PART_SCAN, &disk->state))
+		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 (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);
+
+	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)
+{
+	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);
+	blk_drop_partitions(disk);
+
+	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_inode->i_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;
+}