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>
 19#include <linux/dax.h>
 20#include <linux/blktrace_api.h>
 21
 22#include "partitions/check.h"
 23
 24#ifdef CONFIG_BLK_DEV_MD
 25extern 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
 35char *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
 47const char *bdevname(struct block_device *bdev, char *buf)
 48{
 49	return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
 50}
 51
 52EXPORT_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 */
 59const 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
 66EXPORT_SYMBOL(__bdevname);
 67
 68static 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
 76static 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
 84ssize_t part_size_show(struct device *dev,
 85		       struct device_attribute *attr, char *buf)
 86{
 87	struct hd_struct *p = dev_to_part(dev);
 88	return sprintf(buf, "%llu\n",(unsigned long long)part_nr_sects_read(p));
 89}
 90
 91static 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
 98static 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
105static 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
112ssize_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
139ssize_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
149ssize_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
157ssize_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
171static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
172static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
173static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
174static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
175static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
176static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
177		   NULL);
178static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
179static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
180#ifdef CONFIG_FAIL_MAKE_REQUEST
181static struct device_attribute dev_attr_fail =
182	__ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
183#endif
184
185static 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
200static struct attribute_group part_attr_group = {
201	.attrs = part_attrs,
202};
203
204static 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
212static void part_release(struct device *dev)
213{
214	struct hd_struct *p = dev_to_part(dev);
215	blk_free_devt(dev->devt);
216	hd_free_part(p);
217	kfree(p);
218}
219
220static 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
230struct device_type part_type = {
231	.name		= "partition",
232	.groups		= part_attr_groups,
233	.release	= part_release,
234	.uevent		= part_uevent,
235};
236
237static 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
247void __delete_partition(struct percpu_ref *ref)
248{
249	struct hd_struct *part = container_of(ref, struct hd_struct, ref);
250	call_rcu(&part->rcu_head, delete_partition_rcu_cb);
251}
252
253void 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
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
270	hd_struct_kill(part);
271}
272
273static ssize_t whole_disk_show(struct device *dev,
274			       struct device_attribute *attr, char *buf)
275{
276	return 0;
277}
278static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
279		   whole_disk_show, NULL);
280
281struct 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	}
309
310	seqcount_init(&p->nr_sects_seq);
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	err = hd_ref_init(p);
365	if (err) {
366		if (flags & ADDPART_FLAG_WHOLEDISK)
367			goto out_remove_file;
368		goto out_del;
369	}
370
371	/* everything is up and running, commence */
372	rcu_assign_pointer(ptbl->part[partno], p);
373
374	/* suppress uevent if the disk suppresses it */
375	if (!dev_get_uevent_suppress(ddev))
376		kobject_uevent(&pdev->kobj, KOBJ_ADD);
377	return p;
378
379out_free_info:
380	free_part_info(p);
381out_free_stats:
382	free_part_stats(p);
383out_free:
384	kfree(p);
385	return ERR_PTR(err);
386out_remove_file:
387	device_remove_file(pdev, &dev_attr_whole_disk);
388out_del:
389	kobject_put(p->holder_dir);
390	device_del(pdev);
391out_put:
392	put_device(pdev);
393	blk_free_devt(devt);
394	return ERR_PTR(err);
395}
396
397static bool disk_unlock_native_capacity(struct gendisk *disk)
398{
399	const struct block_device_operations *bdops = disk->fops;
400
401	if (bdops->unlock_native_capacity &&
402	    !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
403		printk(KERN_CONT "enabling native capacity\n");
404		bdops->unlock_native_capacity(disk);
405		disk->flags |= GENHD_FL_NATIVE_CAPACITY;
406		return true;
407	} else {
408		printk(KERN_CONT "truncated\n");
409		return false;
410	}
411}
412
413static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
414{
415	struct disk_part_iter piter;
416	struct hd_struct *part;
417	int res;
418
419	if (bdev->bd_part_count || bdev->bd_super)
420		return -EBUSY;
421	res = invalidate_partition(disk, 0);
422	if (res)
423		return res;
424
425	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
426	while ((part = disk_part_iter_next(&piter)))
427		delete_partition(disk, part->partno);
428	disk_part_iter_exit(&piter);
429
430	return 0;
431}
432
433int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
434{
435	struct parsed_partitions *state = NULL;
436	struct hd_struct *part;
437	int p, highest, res;
438rescan:
439	if (state && !IS_ERR(state)) {
440		free_partitions(state);
441		state = NULL;
442	}
443
444	res = drop_partitions(disk, bdev);
445	if (res)
446		return res;
447
448	if (disk->fops->revalidate_disk)
449		disk->fops->revalidate_disk(disk);
450	blk_integrity_revalidate(disk);
451	check_disk_size_change(disk, bdev);
452	bdev->bd_invalidated = 0;
453	if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
454		return 0;
455	if (IS_ERR(state)) {
456		/*
457		 * I/O error reading the partition table.  If any
458		 * partition code tried to read beyond EOD, retry
459		 * after unlocking native capacity.
460		 */
461		if (PTR_ERR(state) == -ENOSPC) {
462			printk(KERN_WARNING "%s: partition table beyond EOD, ",
463			       disk->disk_name);
464			if (disk_unlock_native_capacity(disk))
465				goto rescan;
466		}
467		return -EIO;
468	}
469	/*
470	 * If any partition code tried to read beyond EOD, try
471	 * unlocking native capacity even if partition table is
472	 * successfully read as we could be missing some partitions.
473	 */
474	if (state->access_beyond_eod) {
475		printk(KERN_WARNING
476		       "%s: partition table partially beyond EOD, ",
477		       disk->disk_name);
478		if (disk_unlock_native_capacity(disk))
479			goto rescan;
480	}
481
482	/* tell userspace that the media / partition table may have changed */
483	kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
484
485	/* Detect the highest partition number and preallocate
486	 * disk->part_tbl.  This is an optimization and not strictly
487	 * necessary.
488	 */
489	for (p = 1, highest = 0; p < state->limit; p++)
490		if (state->parts[p].size)
491			highest = p;
492
493	disk_expand_part_tbl(disk, highest);
494
495	/* add partitions */
496	for (p = 1; p < state->limit; p++) {
497		sector_t size, from;
498		struct partition_meta_info *info = NULL;
499
500		size = state->parts[p].size;
501		if (!size)
502			continue;
503
504		from = state->parts[p].from;
505		if (from >= get_capacity(disk)) {
506			printk(KERN_WARNING
507			       "%s: p%d start %llu is beyond EOD, ",
508			       disk->disk_name, p, (unsigned long long) from);
509			if (disk_unlock_native_capacity(disk))
510				goto rescan;
511			continue;
512		}
513
514		if (from + size > get_capacity(disk)) {
515			printk(KERN_WARNING
516			       "%s: p%d size %llu extends beyond EOD, ",
517			       disk->disk_name, p, (unsigned long long) size);
518
519			if (disk_unlock_native_capacity(disk)) {
520				/* free state and restart */
521				goto rescan;
522			} else {
523				/*
524				 * we can not ignore partitions of broken tables
525				 * created by for example camera firmware, but
526				 * we limit them to the end of the disk to avoid
527				 * creating invalid block devices
528				 */
529				size = get_capacity(disk) - from;
530			}
531		}
532
533		if (state->parts[p].has_info)
534			info = &state->parts[p].info;
535		part = add_partition(disk, p, from, size,
536				     state->parts[p].flags,
537				     &state->parts[p].info);
538		if (IS_ERR(part)) {
539			printk(KERN_ERR " %s: p%d could not be added: %ld\n",
540			       disk->disk_name, p, -PTR_ERR(part));
541			continue;
542		}
543#ifdef CONFIG_BLK_DEV_MD
544		if (state->parts[p].flags & ADDPART_FLAG_RAID)
545			md_autodetect_dev(part_to_dev(part)->devt);
546#endif
547	}
548	free_partitions(state);
549	return 0;
550}
551
552int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
553{
554	int res;
555
556	if (!bdev->bd_invalidated)
557		return 0;
558
559	res = drop_partitions(disk, bdev);
560	if (res)
561		return res;
562
563	set_capacity(disk, 0);
564	check_disk_size_change(disk, bdev);
565	bdev->bd_invalidated = 0;
566	/* tell userspace that the media / partition table may have changed */
567	kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
568
569	return 0;
570}
571
572static struct page *read_pagecache_sector(struct block_device *bdev, sector_t n)
573{
574	struct address_space *mapping = bdev->bd_inode->i_mapping;
575
576	return read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_SHIFT-9)),
577				 NULL);
578}
579
580unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
581{
582	struct page *page;
583
584	/* don't populate page cache for dax capable devices */
585	if (IS_DAX(bdev->bd_inode))
586		page = read_dax_sector(bdev, n);
587	else
588		page = read_pagecache_sector(bdev, n);
589
590	if (!IS_ERR(page)) {
591		if (PageError(page))
592			goto fail;
593		p->v = page;
594		return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << 9);
595fail:
596		put_page(page);
597	}
598	p->v = NULL;
599	return NULL;
600}
601
602EXPORT_SYMBOL(read_dev_sector);