[mirror_ubuntu-zesty-kernel.git] / block / partition-generic.c

/*
 *  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/dax.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);

/*
 * 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);
	int cpu;

	cpu = part_stat_lock();
	part_round_stats(cpu, p);
	part_stat_unlock();
	return sprintf(buf,
		"%8lu %8lu %8llu %8u "
		"%8lu %8lu %8llu %8u "
		"%8u %8u %8u"
		"\n",
		part_stat_read(p, ios[READ]),
		part_stat_read(p, merges[READ]),
		(unsigned long long)part_stat_read(p, sectors[READ]),
		jiffies_to_msecs(part_stat_read(p, ticks[READ])),
		part_stat_read(p, ios[WRITE]),
		part_stat_read(p, merges[WRITE]),
		(unsigned long long)part_stat_read(p, sectors[WRITE]),
		jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
		part_in_flight(p),
		jiffies_to_msecs(part_stat_read(p, io_ticks)),
		jiffies_to_msecs(part_stat_read(p, time_in_queue)));
}

ssize_t part_inflight_show(struct device *dev,
			struct device_attribute *attr, char *buf)
{
	struct hd_struct *p = dev_to_part(dev);

	return sprintf(buf, "%8u %8u\n", atomic_read(&p->in_flight[0]),
		atomic_read(&p->in_flight[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, S_IRUGO, part_partition_show, NULL);
static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
		   NULL);
static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
#ifdef CONFIG_FAIL_MAKE_REQUEST
static struct device_attribute dev_attr_fail =
	__ATTR(make-it-fail, S_IRUGO|S_IWUSR, 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_rcu_cb(struct rcu_head *head)
{
	struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);

	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);
	call_rcu(&part->rcu_head, delete_partition_rcu_cb);
}

void delete_partition(struct gendisk *disk, int partno)
{
	struct disk_part_tbl *ptbl = disk->part_tbl;
	struct hd_struct *part;

	if (partno >= ptbl->len)
		return;

	part = ptbl->part[partno];
	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));

	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, S_IRUSR | S_IRGRP | S_IROTH,
		   whole_disk_show, NULL);

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 = disk->part_tbl;

	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)
			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;
	}

	/* 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);

	if (!hd_ref_init(p))
		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_del:
	kobject_put(p->holder_dir);
	device_del(pdev);
out_put:
	put_device(pdev);
	blk_free_devt(devt);
	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;
}

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);
	blk_integrity_revalidate(disk);
	check_disk_size_change(disk, bdev);
	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;
		struct partition_meta_info *info = NULL;

		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;
			}
		}

		if (state->parts[p].has_info)
			info = &state->parts[p].info;
		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);
	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;
}

static struct page *read_pagecache_sector(struct block_device *bdev, sector_t n)
{
	struct address_space *mapping = bdev->bd_inode->i_mapping;

	return read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
			NULL);
}

unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
{
	struct page *page;

	/* don't populate page cache for dax capable devices */
	if (IS_DAX(bdev->bd_inode))
		page = read_dax_sector(bdev, n);
	else
		page = read_pagecache_sector(bdev, n);

	if (!IS_ERR(page)) {
		if (PageError(page))
			goto fail;
		p->v = page;
		return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
fail:
		page_cache_release(page);
	}
	p->v = NULL;
	return NULL;
}

EXPORT_SYMBOL(read_dev_sector);
Commit	Line	Data
94ea4158 AV	1	/*
	2	* Code extracted from drivers/block/genhd.c
	3	* Copyright (C) 1991-1998 Linus Torvalds
	4	* Re-organised Feb 1998 Russell King
	5	*
	6	* We now have independent partition support from the
	7	* block drivers, which allows all the partition code to
	8	* be grouped in one location, and it to be mostly self
	9	* contained.
	10	*/
	11
	12	#include <linux/init.h>
	13	#include <linux/module.h>
	14	#include <linux/fs.h>
	15	#include <linux/slab.h>
	16	#include <linux/kmod.h>
	17	#include <linux/ctype.h>
	18	#include <linux/genhd.h>
d1a5f2b4	19	#include <linux/dax.h>
94ea4158 AV	20	#include <linux/blktrace_api.h>
	21
	22	#include "partitions/check.h"
	23
	24	#ifdef CONFIG_BLK_DEV_MD
	25	extern void md_autodetect_dev(dev_t dev);
	26	#endif
	27
	28	/*
	29	* disk_name() is used by partition check code and the genhd driver.
	30	* It formats the devicename of the indicated disk into
	31	* the supplied buffer (of size at least 32), and returns
	32	* a pointer to that same buffer (for convenience).
	33	*/
	34
	35	char disk_name(struct gendisk hd, int partno, char *buf)
	36	{
	37	if (!partno)
	38	snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
	39	else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
	40	snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
	41	else
	42	snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
	43
	44	return buf;
	45	}
	46
	47	const char bdevname(struct block_device bdev, char *buf)
	48	{
	49	return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
	50	}
	51
	52	EXPORT_SYMBOL(bdevname);
	53
	54	/*
	55	* There's very little reason to use this, you should really
	56	* have a struct block_device just about everywhere and use
	57	* bdevname() instead.
	58	*/
	59	const char __bdevname(dev_t dev, char buffer)
	60	{
	61	scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
	62	MAJOR(dev), MINOR(dev));
	63	return buffer;
	64	}
	65
	66	EXPORT_SYMBOL(__bdevname);
	67
	68	static ssize_t part_partition_show(struct device *dev,
	69	struct device_attribute attr, char buf)
	70	{
	71	struct hd_struct *p = dev_to_part(dev);
	72
	73	return sprintf(buf, "%d\n", p->partno);
	74	}
	75
	76	static ssize_t part_start_show(struct device *dev,
	77	struct device_attribute attr, char buf)
	78	{
	79	struct hd_struct *p = dev_to_part(dev);
	80
	81	return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
	82	}
	83
84	ssize_t part_size_show(struct device *dev,
85	struct device_attribute attr, char buf)
86	{
87	struct hd_struct *p = dev_to_part(dev);
c83f6bf9	88	return sprintf(buf, "%llu\n",(unsigned long long)part_nr_sects_read(p));
94ea4158 AV	89	}
	90
	91	static ssize_t part_ro_show(struct device *dev,
	92	struct device_attribute attr, char buf)
	93	{
	94	struct hd_struct *p = dev_to_part(dev);
	95	return sprintf(buf, "%d\n", p->policy ? 1 : 0);
	96	}
	97
	98	static ssize_t part_alignment_offset_show(struct device *dev,
	99	struct device_attribute attr, char buf)
	100	{
	101	struct hd_struct *p = dev_to_part(dev);
	102	return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
	103	}
	104
	105	static ssize_t part_discard_alignment_show(struct device *dev,
	106	struct device_attribute attr, char buf)
	107	{
	108	struct hd_struct *p = dev_to_part(dev);
	109	return sprintf(buf, "%u\n", p->discard_alignment);
	110	}
	111
	112	ssize_t part_stat_show(struct device *dev,
	113	struct device_attribute attr, char buf)
	114	{
	115	struct hd_struct *p = dev_to_part(dev);
	116	int cpu;
	117
	118	cpu = part_stat_lock();
	119	part_round_stats(cpu, p);
	120	part_stat_unlock();
	121	return sprintf(buf,
	122	"%8lu %8lu %8llu %8u "
	123	"%8lu %8lu %8llu %8u "
	124	"%8u %8u %8u"
	125	"\n",
	126	part_stat_read(p, ios[READ]),
	127	part_stat_read(p, merges[READ]),
	128	(unsigned long long)part_stat_read(p, sectors[READ]),
	129	jiffies_to_msecs(part_stat_read(p, ticks[READ])),
	130	part_stat_read(p, ios[WRITE]),
	131	part_stat_read(p, merges[WRITE]),
	132	(unsigned long long)part_stat_read(p, sectors[WRITE]),
	133	jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
	134	part_in_flight(p),
	135	jiffies_to_msecs(part_stat_read(p, io_ticks)),
	136	jiffies_to_msecs(part_stat_read(p, time_in_queue)));
	137	}
	138
	139	ssize_t part_inflight_show(struct device *dev,
	140	struct device_attribute attr, char buf)
	141	{
	142	struct hd_struct *p = dev_to_part(dev);
	143
	144	return sprintf(buf, "%8u %8u\n", atomic_read(&p->in_flight[0]),
	145	atomic_read(&p->in_flight[1]));
	146	}
	147
	148	#ifdef CONFIG_FAIL_MAKE_REQUEST
	149	ssize_t part_fail_show(struct device *dev,
	150	struct device_attribute attr, char buf)
	151	{
	152	struct hd_struct *p = dev_to_part(dev);
153
154	return sprintf(buf, "%d\n", p->make_it_fail);
155	}
156
157	ssize_t part_fail_store(struct device *dev,
158	struct device_attribute *attr,
159	const char *buf, size_t count)
160	{
161	struct hd_struct *p = dev_to_part(dev);
162	int i;
163
164	if (count > 0 && sscanf(buf, "%d", &i) > 0)
165	p->make_it_fail = (i == 0) ? 0 : 1;
166
167	return count;
168	}
169	#endif
170
171	static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
172	static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
173	static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
174	static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
175	static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
176	static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
177	NULL);
178	static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
179	static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
180	#ifdef CONFIG_FAIL_MAKE_REQUEST
181	static struct device_attribute dev_attr_fail =
182	__ATTR(make-it-fail, S_IRUGO\|S_IWUSR, part_fail_show, part_fail_store);
183	#endif
184
185	static struct attribute *part_attrs[] = {
186	&dev_attr_partition.attr,
187	&dev_attr_start.attr,
188	&dev_attr_size.attr,
189	&dev_attr_ro.attr,
190	&dev_attr_alignment_offset.attr,
191	&dev_attr_discard_alignment.attr,
192	&dev_attr_stat.attr,
193	&dev_attr_inflight.attr,
194	#ifdef CONFIG_FAIL_MAKE_REQUEST
195	&dev_attr_fail.attr,
196	#endif
197	NULL
198	};
199
200	static struct attribute_group part_attr_group = {
201	.attrs = part_attrs,
202	};
203
204	static const struct attribute_group *part_attr_groups[] = {
205	&part_attr_group,
206	#ifdef CONFIG_BLK_DEV_IO_TRACE
207	&blk_trace_attr_group,
208	#endif
209	NULL
210	};
211
212	static void part_release(struct device *dev)
213	{
214	struct hd_struct *p = dev_to_part(dev);
2da78092	215	blk_free_devt(dev->devt);
b54e5ed8	216	hd_free_part(p);
94ea4158 AV	217	kfree(p);
	218	}
	219
0d9c51a6 SM	220	static int part_uevent(struct device dev, struct kobj_uevent_env env)
	221	{
	222	struct hd_struct *part = dev_to_part(dev);
	223
	224	add_uevent_var(env, "PARTN=%u", part->partno);
	225	if (part->info && part->info->volname[0])
	226	add_uevent_var(env, "PARTNAME=%s", part->info->volname);
	227	return 0;
	228	}
	229
94ea4158 AV	230	struct device_type part_type = {
	231	.name = "partition",
	232	.groups = part_attr_groups,
	233	.release = part_release,
0d9c51a6	234	.uevent = part_uevent,
94ea4158 AV	235	};
	236
	237	static void delete_partition_rcu_cb(struct rcu_head *head)
	238	{
	239	struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
	240
	241	part->start_sect = 0;
	242	part->nr_sects = 0;
	243	part_stat_set_all(part, 0);
	244	put_device(part_to_dev(part));
	245	}
	246
6c71013e	247	void __delete_partition(struct percpu_ref *ref)
94ea4158	248	{
6c71013e	249	struct hd_struct *part = container_of(ref, struct hd_struct, ref);
94ea4158 AV	250	call_rcu(&part->rcu_head, delete_partition_rcu_cb);
	251	}
	252
	253	void delete_partition(struct gendisk *disk, int partno)
	254	{
	255	struct disk_part_tbl *ptbl = disk->part_tbl;
	256	struct hd_struct *part;
	257
	258	if (partno >= ptbl->len)
	259	return;
	260
	261	part = ptbl->part[partno];
	262	if (!part)
	263	return;
	264
94ea4158 AV	265	rcu_assign_pointer(ptbl->part[partno], NULL);
	266	rcu_assign_pointer(ptbl->last_lookup, NULL);
	267	kobject_put(part->holder_dir);
	268	device_del(part_to_dev(part));
	269
6c71013e	270	hd_struct_kill(part);
94ea4158 AV	271	}
	272
	273	static ssize_t whole_disk_show(struct device *dev,
	274	struct device_attribute attr, char buf)
	275	{
	276	return 0;
	277	}
	278	static DEVICE_ATTR(whole_disk, S_IRUSR \| S_IRGRP \| S_IROTH,
	279	whole_disk_show, NULL);
	280
	281	struct hd_struct add_partition(struct gendisk disk, int partno,
	282	sector_t start, sector_t len, int flags,
	283	struct partition_meta_info *info)
	284	{
	285	struct hd_struct *p;
	286	dev_t devt = MKDEV(0, 0);
	287	struct device *ddev = disk_to_dev(disk);
	288	struct device *pdev;
	289	struct disk_part_tbl *ptbl;
	290	const char *dname;
	291	int err;
	292
	293	err = disk_expand_part_tbl(disk, partno);
	294	if (err)
	295	return ERR_PTR(err);
	296	ptbl = disk->part_tbl;
	297
	298	if (ptbl->part[partno])
	299	return ERR_PTR(-EBUSY);
	300
	301	p = kzalloc(sizeof(*p), GFP_KERNEL);
	302	if (!p)
	303	return ERR_PTR(-EBUSY);
	304
	305	if (!init_part_stats(p)) {
	306	err = -ENOMEM;
	307	goto out_free;
	308	}
c83f6bf9 VG	309
c83f6bf9 VG	310	seqcount_init(&p->nr_sects_seq);
94ea4158 AV	311	pdev = part_to_dev(p);
	312
	313	p->start_sect = start;
	314	p->alignment_offset =
	315	queue_limit_alignment_offset(&disk->queue->limits, start);
	316	p->discard_alignment =
	317	queue_limit_discard_alignment(&disk->queue->limits, start);
	318	p->nr_sects = len;
	319	p->partno = partno;
	320	p->policy = get_disk_ro(disk);
	321
	322	if (info) {
	323	struct partition_meta_info *pinfo = alloc_part_info(disk);
	324	if (!pinfo)
	325	goto out_free_stats;
	326	memcpy(pinfo, info, sizeof(*info));
	327	p->info = pinfo;
	328	}
	329
	330	dname = dev_name(ddev);
	331	if (isdigit(dname[strlen(dname) - 1]))
	332	dev_set_name(pdev, "%sp%d", dname, partno);
	333	else
	334	dev_set_name(pdev, "%s%d", dname, partno);
	335
	336	device_initialize(pdev);
	337	pdev->class = &block_class;
	338	pdev->type = &part_type;
	339	pdev->parent = ddev;
	340
	341	err = blk_alloc_devt(p, &devt);
	342	if (err)
	343	goto out_free_info;
	344	pdev->devt = devt;
	345
	346	/* delay uevent until 'holders' subdir is created */
	347	dev_set_uevent_suppress(pdev, 1);
	348	err = device_add(pdev);
	349	if (err)
	350	goto out_put;
	351
	352	err = -ENOMEM;
	353	p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
	354	if (!p->holder_dir)
	355	goto out_del;
	356
	357	dev_set_uevent_suppress(pdev, 0);
	358	if (flags & ADDPART_FLAG_WHOLEDISK) {
	359	err = device_create_file(pdev, &dev_attr_whole_disk);
	360	if (err)
	361	goto out_del;
	362	}
	363
	364	/* everything is up and running, commence */
	365	rcu_assign_pointer(ptbl->part[partno], p);
	366
	367	/* suppress uevent if the disk suppresses it */
	368	if (!dev_get_uevent_suppress(ddev))
	369	kobject_uevent(&pdev->kobj, KOBJ_ADD);
	370
6c71013e ML	371	if (!hd_ref_init(p))
6c71013e ML	372	return p;
94ea4158 AV	373
	374	out_free_info:
	375	free_part_info(p);
	376	out_free_stats:
	377	free_part_stats(p);
	378	out_free:
	379	kfree(p);
	380	return ERR_PTR(err);
	381	out_del:
	382	kobject_put(p->holder_dir);
	383	device_del(pdev);
	384	out_put:
	385	put_device(pdev);
	386	blk_free_devt(devt);
	387	return ERR_PTR(err);
	388	}
	389
	390	static bool disk_unlock_native_capacity(struct gendisk *disk)
	391	{
	392	const struct block_device_operations *bdops = disk->fops;
	393
	394	if (bdops->unlock_native_capacity &&
	395	!(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
	396	printk(KERN_CONT "enabling native capacity\n");
	397	bdops->unlock_native_capacity(disk);
	398	disk->flags \|= GENHD_FL_NATIVE_CAPACITY;
	399	return true;
	400	} else {
	401	printk(KERN_CONT "truncated\n");
	402	return false;
	403	}
	404	}
	405
fe316bf2	406	static int drop_partitions(struct gendisk disk, struct block_device bdev)
94ea4158	407	{
94ea4158 AV	408	struct disk_part_iter piter;
94ea4158 AV	409	struct hd_struct *part;
fe316bf2	410	int res;
94ea4158	411
77032ca6	412	if (bdev->bd_part_count \|\| bdev->bd_super)
94ea4158 AV	413	return -EBUSY;
	414	res = invalidate_partition(disk, 0);
	415	if (res)
	416	return res;
	417
	418	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
	419	while ((part = disk_part_iter_next(&piter)))
	420	delete_partition(disk, part->partno);
	421	disk_part_iter_exit(&piter);
	422
fe316bf2 JN	423	return 0;
	424	}
	425
	426	int rescan_partitions(struct gendisk disk, struct block_device bdev)
	427	{
	428	struct parsed_partitions *state = NULL;
	429	struct hd_struct *part;
	430	int p, highest, res;
	431	rescan:
	432	if (state && !IS_ERR(state)) {
ac2e5327	433	free_partitions(state);
fe316bf2 JN	434	state = NULL;
	435	}
	436
	437	res = drop_partitions(disk, bdev);
	438	if (res)
	439	return res;
	440
94ea4158 AV	441	if (disk->fops->revalidate_disk)
94ea4158 AV	442	disk->fops->revalidate_disk(disk);
25520d55	443	blk_integrity_revalidate(disk);
94ea4158 AV	444	check_disk_size_change(disk, bdev);
	445	bdev->bd_invalidated = 0;
	446	if (!get_capacity(disk) \|\| !(state = check_partition(disk, bdev)))
	447	return 0;
	448	if (IS_ERR(state)) {
	449	/*
	450	* I/O error reading the partition table. If any
	451	* partition code tried to read beyond EOD, retry
	452	* after unlocking native capacity.
	453	*/
	454	if (PTR_ERR(state) == -ENOSPC) {
	455	printk(KERN_WARNING "%s: partition table beyond EOD, ",
	456	disk->disk_name);
	457	if (disk_unlock_native_capacity(disk))
	458	goto rescan;
	459	}
	460	return -EIO;
	461	}
	462	/*
	463	* If any partition code tried to read beyond EOD, try
	464	* unlocking native capacity even if partition table is
	465	* successfully read as we could be missing some partitions.
	466	*/
	467	if (state->access_beyond_eod) {
	468	printk(KERN_WARNING
	469	"%s: partition table partially beyond EOD, ",
	470	disk->disk_name);
	471	if (disk_unlock_native_capacity(disk))
	472	goto rescan;
	473	}
	474
	475	/* tell userspace that the media / partition table may have changed */
	476	kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
	477
	478	/* Detect the highest partition number and preallocate
	479	* disk->part_tbl. This is an optimization and not strictly
	480	* necessary.
	481	*/
	482	for (p = 1, highest = 0; p < state->limit; p++)
	483	if (state->parts[p].size)
	484	highest = p;
	485
	486	disk_expand_part_tbl(disk, highest);
	487
	488	/* add partitions */
	489	for (p = 1; p < state->limit; p++) {
	490	sector_t size, from;
	491	struct partition_meta_info *info = NULL;
	492
	493	size = state->parts[p].size;
	494	if (!size)
	495	continue;
	496
	497	from = state->parts[p].from;
	498	if (from >= get_capacity(disk)) {
	499	printk(KERN_WARNING
	500	"%s: p%d start %llu is beyond EOD, ",
	501	disk->disk_name, p, (unsigned long long) from);
	502	if (disk_unlock_native_capacity(disk))
	503	goto rescan;
	504	continue;
	505	}
	506
	507	if (from + size > get_capacity(disk)) {
508	printk(KERN_WARNING
509	"%s: p%d size %llu extends beyond EOD, ",
510	disk->disk_name, p, (unsigned long long) size);
511
512	if (disk_unlock_native_capacity(disk)) {
513	/* free state and restart */
514	goto rescan;
515	} else {
516	/*
517	* we can not ignore partitions of broken tables
518	* created by for example camera firmware, but
519	* we limit them to the end of the disk to avoid
520	* creating invalid block devices
521	*/
522	size = get_capacity(disk) - from;
523	}
524	}
525
526	if (state->parts[p].has_info)
527	info = &state->parts[p].info;
528	part = add_partition(disk, p, from, size,
529	state->parts[p].flags,
530	&state->parts[p].info);
531	if (IS_ERR(part)) {
532	printk(KERN_ERR " %s: p%d could not be added: %ld\n",
533	disk->disk_name, p, -PTR_ERR(part));
534	continue;
535	}
536	#ifdef CONFIG_BLK_DEV_MD
537	if (state->parts[p].flags & ADDPART_FLAG_RAID)
538	md_autodetect_dev(part_to_dev(part)->devt);
539	#endif
540	}
ac2e5327	541	free_partitions(state);
94ea4158 AV	542	return 0;
	543	}
	544
fe316bf2 JN	545	int invalidate_partitions(struct gendisk disk, struct block_device bdev)
	546	{
	547	int res;
	548
	549	if (!bdev->bd_invalidated)
	550	return 0;
	551
	552	res = drop_partitions(disk, bdev);
	553	if (res)
	554	return res;
	555
	556	set_capacity(disk, 0);
	557	check_disk_size_change(disk, bdev);
	558	bdev->bd_invalidated = 0;
	559	/* tell userspace that the media / partition table may have changed */
	560	kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
	561
	562	return 0;
	563	}
	564
d1a5f2b4	565	static struct page read_pagecache_sector(struct block_device bdev, sector_t n)
94ea4158 AV	566	{
94ea4158 AV	567	struct address_space *mapping = bdev->bd_inode->i_mapping;
d1a5f2b4 DW	568
	569	return read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
	570	NULL);
	571	}
	572
	573	unsigned char read_dev_sector(struct block_device bdev, sector_t n, Sector *p)
	574	{
94ea4158 AV	575	struct page *page;
94ea4158 AV	576
d1a5f2b4 DW	577	/* don't populate page cache for dax capable devices */
	578	if (IS_DAX(bdev->bd_inode))
	579	page = read_dax_sector(bdev, n);
	580	else
	581	page = read_pagecache_sector(bdev, n);
	582
94ea4158 AV	583	if (!IS_ERR(page)) {
	584	if (PageError(page))
	585	goto fail;
	586	p->v = page;
	587	return (unsigned char *)page_address(page) + ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
	588	fail:
	589	page_cache_release(page);
	590	}
	591	p->v = NULL;
	592	return NULL;
	593	}
	594
	595	EXPORT_SYMBOL(read_dev_sector);