/*
   *  fs/partitions/check.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.
   *
   *  Added needed MAJORS for new pairs, {hdi,hdj}, {hdk,hdl}
   */
  
  #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 "check.h"

  
  #include "acorn.h"
  #include "amiga.h"
  #include "atari.h"
  #include "ldm.h"
  #include "mac.h"
  #include "msdos.h"
  #include "osf.h"
  #include "sgi.h"
  #include "sun.h"
  #include "ibm.h"
  #include "ultrix.h"
  #include "efi.h"

  #include "karma.h"

  #include "sysv68.h"

  
  #ifdef CONFIG_BLK_DEV_MD
  extern void md_autodetect_dev(dev_t dev);
  #endif
  
  int warn_no_part = 1; /*This is ugly: should make genhd removable media aware*/

  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_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
  };
   
  /*
   * 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 struct parsed_partitions *
  check_partition(struct gendisk *hd, struct block_device *bdev)
  {
  	struct parsed_partitions *state;

  	int i, res, err;

  	state = kzalloc(sizeof(struct parsed_partitions), GFP_KERNEL);

  	if (!state)
  		return NULL;

  	state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
  	if (!state->pp_buf) {
  		kfree(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");

  	state->limit = disk_max_parts(hd);

  	i = res = err = 0;

  	while (!res && check_part[i]) {
  		memset(&state->parts, 0, sizeof(state->parts));

  		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;

  	if (err)

  	/* The partition is unrecognized. So report I/O errors if there were any */
  		res = err;

  	if (!res)

  		strlcat(state->pp_buf, " unknown partition table
  ", PAGE_SIZE);

  	else if (warn_no_part)

  		strlcat(state->pp_buf, " unable to read partition table
  ", PAGE_SIZE);
  
  	printk(KERN_INFO "%s", state->pp_buf);
  
  	free_page((unsigned long)state->pp_buf);

  	kfree(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
  ", 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
  ",(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
  ",(unsigned long long)p->nr_sects);

  }

  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
  ", 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
  ", (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
  ", 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"
  		"
  ",
  		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
  ", 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
  ", 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);

  	free_part_stats(p);

  	free_part_info(p);

  	kfree(p);
  }

  struct device_type part_type = {
  	.name		= "partition",
  	.groups		= part_attr_groups,

  	.release	= part_release,

  };

  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 hd_struct *part)

  {

  	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;

  	blk_free_devt(part_devt(part));

  	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_put(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;

  	}

  	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);

  	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
  ");
  		bdops->unlock_native_capacity(disk);
  		disk->flags |= GENHD_FL_NATIVE_CAPACITY;
  		return true;
  	} else {
  		printk(KERN_CONT "truncated
  ");
  		return false;
  	}
  }

  int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
  {

  	struct parsed_partitions *state = NULL;

  	struct disk_part_iter piter;
  	struct hd_struct *part;

  	int p, highest, res;

  rescan:

  	if (state && !IS_ERR(state)) {
  		kfree(state);
  		state = NULL;
  	}

  	if (bdev->bd_part_count)
  		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);

  	if (disk->fops->revalidate_disk)
  		disk->fops->revalidate_disk(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
  ",
  			       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
  	}
  	kfree(state);
  	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_CACHE_SHIFT-9)),
  				 NULL);

  	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);