1 files changed, 684 insertions, 0 deletions

diff --git a/block/partition-generic.c b/block/partition-generic.c
new file mode 100644
index 000000000..98d60a59b
--- /dev/null
+++ b/block/partition-generic.c
@@ -0,0 +1,684 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Code extracted from drivers/block/genhd.c
+ *  Copyright (C) 1991-1998  Linus Torvalds
+ *  Re-organised Feb 1998 Russell King
+ *
+ *  We now have independent partition support from the
+ *  block drivers, which allows all the partition code to
+ *  be grouped in one location, and it to be mostly self
+ *  contained.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/kmod.h>
+#include <linux/ctype.h>
+#include <linux/genhd.h>
+#include <linux/blktrace_api.h>
+
+#include "partitions/check.h"
+
+#ifdef CONFIG_BLK_DEV_MD
+extern void md_autodetect_dev(dev_t dev);
+#endif
+ 
+/*
+ * disk_name() is used by partition check code and the genhd driver.
+ * It formats the devicename of the indicated disk into
+ * the supplied buffer (of size at least 32), and returns
+ * a pointer to that same buffer (for convenience).
+ */
+
+char *disk_name(struct gendisk *hd, int partno, char *buf)
+{
+	if (!partno)
+		snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
+	else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
+		snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
+	else
+		snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
+
+	return buf;
+}
+
+const char *bdevname(struct block_device *bdev, char *buf)
+{
+	return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
+}
+
+EXPORT_SYMBOL(bdevname);
+
+const char *bio_devname(struct bio *bio, char *buf)
+{
+	return disk_name(bio->bi_disk, bio->bi_partno, buf);
+}
+EXPORT_SYMBOL(bio_devname);
+
+/*
+ * There's very little reason to use this, you should really
+ * have a struct block_device just about everywhere and use
+ * bdevname() instead.
+ */
+const char *__bdevname(dev_t dev, char *buffer)
+{
+	scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
+				MAJOR(dev), MINOR(dev));
+	return buffer;
+}
+
+EXPORT_SYMBOL(__bdevname);
+
+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);
+}
+
+ssize_t part_size_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)part_nr_sects_read(p));
+}
+
+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);
+}
+
+ssize_t part_stat_show(struct device *dev,
+		       struct device_attribute *attr, char *buf)
+{
+	struct hd_struct *p = dev_to_part(dev);
+	struct request_queue *q = part_to_disk(p)->queue;
+	unsigned int inflight[2];
+	int cpu;
+
+	cpu = part_stat_lock();
+	part_round_stats(q, cpu, p);
+	part_stat_unlock();
+	part_in_flight(q, p, inflight);
+	return sprintf(buf,
+		"%8lu %8lu %8llu %8u "
+		"%8lu %8lu %8llu %8u "
+		"%8u %8u %8u "
+		"%8lu %8lu %8llu %8u"
+		"\n",
+		part_stat_read(p, ios[STAT_READ]),
+		part_stat_read(p, merges[STAT_READ]),
+		(unsigned long long)part_stat_read(p, sectors[STAT_READ]),
+		(unsigned int)part_stat_read_msecs(p, STAT_READ),
+		part_stat_read(p, ios[STAT_WRITE]),
+		part_stat_read(p, merges[STAT_WRITE]),
+		(unsigned long long)part_stat_read(p, sectors[STAT_WRITE]),
+		(unsigned int)part_stat_read_msecs(p, STAT_WRITE),
+		inflight[0],
+		jiffies_to_msecs(part_stat_read(p, io_ticks)),
+		jiffies_to_msecs(part_stat_read(p, time_in_queue)),
+		part_stat_read(p, ios[STAT_DISCARD]),
+		part_stat_read(p, merges[STAT_DISCARD]),
+		(unsigned long long)part_stat_read(p, sectors[STAT_DISCARD]),
+		(unsigned int)part_stat_read_msecs(p, STAT_DISCARD));
+}
+
+ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct hd_struct *p = dev_to_part(dev);
+	struct request_queue *q = part_to_disk(p)->queue;
+	unsigned int inflight[2];
+
+	part_in_flight_rw(q, p, inflight);
+	return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);
+}
+
+#ifdef CONFIG_FAIL_MAKE_REQUEST
+ssize_t part_fail_show(struct device *dev,
+		       struct device_attribute *attr, char *buf)
+{
+	struct hd_struct *p = dev_to_part(dev);
+
+	return sprintf(buf, "%d\n", p->make_it_fail);
+}
+
+ssize_t part_fail_store(struct device *dev,
+			struct device_attribute *attr,
+			const char *buf, size_t count)
+{
+	struct hd_struct *p = dev_to_part(dev);
+	int i;
+
+	if (count > 0 && sscanf(buf, "%d", &i) > 0)
+		p->make_it_fail = (i == 0) ? 0 : 1;
+
+	return count;
+}
+#endif
+
+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 delete_partition_work_fn(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));
+}
+
+void __delete_partition(struct percpu_ref *ref)
+{
+	struct hd_struct *part = container_of(ref, struct hd_struct, ref);
+	INIT_RCU_WORK(&part->rcu_work, delete_partition_work_fn);
+	queue_rcu_work(system_wq, &part->rcu_work);
+}
+
+/*
+ * 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, int partno)
+{
+	struct disk_part_tbl *ptbl =
+		rcu_dereference_protected(disk->part_tbl, 1);
+	struct hd_struct *part;
+
+	if (partno >= ptbl->len)
+		return;
+
+	part = rcu_dereference_protected(ptbl->part[partno], 1);
+	if (!part)
+		return;
+
+	rcu_assign_pointer(ptbl->part[partno], NULL);
+	rcu_assign_pointer(ptbl->last_lookup, 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));
+	hd_struct_kill(part);
+}
+
+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.
+ */
+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;
+
+	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);
+
+	if (!init_part_stats(p)) {
+		err = -ENOMEM;
+		goto out_free;
+	}
+
+	seqcount_init(&p->nr_sects_seq);
+	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 = alloc_part_info(disk);
+		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:
+	free_part_info(p);
+out_free_stats:
+	free_part_stats(p);
+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 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;
+	}
+}
+
+static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
+{
+	struct disk_part_iter piter;
+	struct hd_struct *part;
+	int res;
+
+	if (bdev->bd_part_count || bdev->bd_super)
+		return -EBUSY;
+	res = invalidate_partition(disk, 0);
+	if (res)
+		return res;
+
+	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
+	while ((part = disk_part_iter_next(&piter)))
+		delete_partition(disk, part->partno);
+	disk_part_iter_exit(&piter);
+
+	return 0;
+}
+
+static bool part_zone_aligned(struct gendisk *disk,
+			      struct block_device *bdev,
+			      sector_t from, sector_t size)
+{
+	unsigned int zone_sectors = bdev_zone_sectors(bdev);
+
+	/*
+	 * If this function is called, then the disk is a zoned block device
+	 * (host-aware or host-managed). This can be detected even if the
+	 * zoned block device support is disabled (CONFIG_BLK_DEV_ZONED not
+	 * set). In this case, however, only host-aware devices will be seen
+	 * as a block device is not created for host-managed devices. Without
+	 * zoned block device support, host-aware drives can still be used as
+	 * regular block devices (no zone operation) and their zone size will
+	 * be reported as 0. Allow this case.
+	 */
+	if (!zone_sectors)
+		return true;
+
+	/*
+	 * Check partition start and size alignement. If the drive has a
+	 * smaller last runt zone, ignore it and allow the partition to
+	 * use it. Check the zone size too: it should be a power of 2 number
+	 * of sectors.
+	 */
+	if (WARN_ON_ONCE(!is_power_of_2(zone_sectors))) {
+		u32 rem;
+
+		div_u64_rem(from, zone_sectors, &rem);
+		if (rem)
+			return false;
+		if ((from + size) < get_capacity(disk)) {
+			div_u64_rem(size, zone_sectors, &rem);
+			if (rem)
+				return false;
+		}
+
+	} else {
+
+		if (from & (zone_sectors - 1))
+			return false;
+		if ((from + size) < get_capacity(disk) &&
+		    (size & (zone_sectors - 1)))
+			return false;
+
+	}
+
+	return true;
+}
+
+int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
+{
+	struct parsed_partitions *state = NULL;
+	struct hd_struct *part;
+	int p, highest, res;
+rescan:
+	if (state && !IS_ERR(state)) {
+		free_partitions(state);
+		state = NULL;
+	}
+
+	res = drop_partitions(disk, bdev);
+	if (res)
+		return res;
+
+	if (disk->fops->revalidate_disk)
+		disk->fops->revalidate_disk(disk);
+	check_disk_size_change(disk, bdev, true);
+	bdev->bd_invalidated = 0;
+	if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
+		return 0;
+	if (IS_ERR(state)) {
+		/*
+		 * I/O error reading the partition table.  If any
+		 * partition code tried to read beyond EOD, retry
+		 * after unlocking native capacity.
+		 */
+		if (PTR_ERR(state) == -ENOSPC) {
+			printk(KERN_WARNING "%s: partition table beyond EOD, ",
+			       disk->disk_name);
+			if (disk_unlock_native_capacity(disk))
+				goto rescan;
+		}
+		return -EIO;
+	}
+	/*
+	 * If any partition code tried to read beyond EOD, try
+	 * unlocking native capacity even if partition table is
+	 * 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 rescan;
+	}
+
+	/* 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);
+
+	/* add partitions */
+	for (p = 1; p < state->limit; p++) {
+		sector_t size, from;
+
+		size = state->parts[p].size;
+		if (!size)
+			continue;
+
+		from = state->parts[p].from;
+		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))
+				goto rescan;
+			continue;
+		}
+
+		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)) {
+				/* free state and restart */
+				goto rescan;
+			} else {
+				/*
+				 * 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;
+			}
+		}
+
+		/*
+		 * On a zoned block device, partitions should be aligned on the
+		 * device zone size (i.e. zone boundary crossing not allowed).
+		 * Otherwise, resetting the write pointer of the last zone of
+		 * one partition may impact the following partition.
+		 */
+		if (bdev_is_zoned(bdev) &&
+		    !part_zone_aligned(disk, bdev, from, size)) {
+			printk(KERN_WARNING
+			       "%s: p%d start %llu+%llu is not zone aligned\n",
+			       disk->disk_name, p, (unsigned long long) from,
+			       (unsigned long long) size);
+			continue;
+		}
+
+		part = add_partition(disk, p, from, size,
+				     state->parts[p].flags,
+				     &state->parts[p].info);
+		if (IS_ERR(part)) {
+			printk(KERN_ERR " %s: p%d could not be added: %ld\n",
+			       disk->disk_name, p, -PTR_ERR(part));
+			continue;
+		}
+#ifdef CONFIG_BLK_DEV_MD
+		if (state->parts[p].flags & ADDPART_FLAG_RAID)
+			md_autodetect_dev(part_to_dev(part)->devt);
+#endif
+	}
+	free_partitions(state);
+	return 0;
+}
+
+int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
+{
+	int res;
+
+	if (!bdev->bd_invalidated)
+		return 0;
+
+	res = drop_partitions(disk, bdev);
+	if (res)
+		return res;
+
+	set_capacity(disk, 0);
+	check_disk_size_change(disk, bdev, false);
+	bdev->bd_invalidated = 0;
+	/* tell userspace that the media / partition table may have changed */
+	kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
+
+	return 0;
+}
+
+unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
+{
+	struct address_space *mapping = bdev->bd_inode->i_mapping;
+	struct page *page;
+
+	page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_SHIFT-9)), NULL);
+	if (!IS_ERR(page)) {
+		if (PageError(page))
+			goto fail;
+		p->v = page;
+		return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << 9);
+fail:
+		put_page(page);
+	}
+	p->v = NULL;
+	return NULL;
+}
+
+EXPORT_SYMBOL(read_dev_sector);