1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Code extracted from drivers/block/genhd.c
4 * Copyright (C) 1991-1998 Linus Torvalds
5 * Re-organised Feb 1998 Russell King
6 *
7 * We now have independent partition support from the
8 * block drivers, which allows all the partition code to
9 * be grouped in one location, and it to be mostly self
10 * contained.
11 */
12
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/fs.h>
16 #include <linux/slab.h>
17 #include <linux/kmod.h>
18 #include <linux/ctype.h>
19 #include <linux/genhd.h>
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 const char *bio_devname(struct bio *bio, char *buf)
55 {
56 return disk_name(bio->bi_disk, bio->bi_partno, buf);
57 }
58 EXPORT_SYMBOL(bio_devname);
59
60 /*
61 * There's very little reason to use this, you should really
62 * have a struct block_device just about everywhere and use
63 * bdevname() instead.
64 */
65 const char *__bdevname(dev_t dev, char *buffer)
66 {
67 scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
68 MAJOR(dev), MINOR(dev));
69 return buffer;
70 }
71
72 EXPORT_SYMBOL(__bdevname);
73
74 static ssize_t part_partition_show(struct device *dev,
75 struct device_attribute *attr, char *buf)
76 {
77 struct hd_struct *p = dev_to_part(dev);
78
79 return sprintf(buf, "%d\n", p->partno);
80 }
81
82 static ssize_t part_start_show(struct device *dev,
83 struct device_attribute *attr, char *buf)
84 {
85 struct hd_struct *p = dev_to_part(dev);
86
87 return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
88 }
89
90 ssize_t part_size_show(struct device *dev,
91 struct device_attribute *attr, char *buf)
92 {
93 struct hd_struct *p = dev_to_part(dev);
94 return sprintf(buf, "%llu\n",(unsigned long long)part_nr_sects_read(p));
95 }
96
97 static ssize_t part_ro_show(struct device *dev,
98 struct device_attribute *attr, char *buf)
99 {
100 struct hd_struct *p = dev_to_part(dev);
101 return sprintf(buf, "%d\n", p->policy ? 1 : 0);
102 }
103
104 static ssize_t part_alignment_offset_show(struct device *dev,
105 struct device_attribute *attr, char *buf)
106 {
107 struct hd_struct *p = dev_to_part(dev);
108 return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
109 }
110
111 static ssize_t part_discard_alignment_show(struct device *dev,
112 struct device_attribute *attr, char *buf)
113 {
114 struct hd_struct *p = dev_to_part(dev);
115 return sprintf(buf, "%u\n", p->discard_alignment);
116 }
117
118 ssize_t part_stat_show(struct device *dev,
119 struct device_attribute *attr, char *buf)
120 {
121 struct hd_struct *p = dev_to_part(dev);
122 struct request_queue *q = part_to_disk(p)->queue;
123 unsigned int inflight;
124
125 inflight = part_in_flight(q, p);
126 return sprintf(buf,
127 "%8lu %8lu %8llu %8u "
128 "%8lu %8lu %8llu %8u "
129 "%8u %8u %8u "
130 "%8lu %8lu %8llu %8u"
131 "\n",
132 part_stat_read(p, ios[STAT_READ]),
133 part_stat_read(p, merges[STAT_READ]),
134 (unsigned long long)part_stat_read(p, sectors[STAT_READ]),
135 (unsigned int)part_stat_read_msecs(p, STAT_READ),
136 part_stat_read(p, ios[STAT_WRITE]),
137 part_stat_read(p, merges[STAT_WRITE]),
138 (unsigned long long)part_stat_read(p, sectors[STAT_WRITE]),
139 (unsigned int)part_stat_read_msecs(p, STAT_WRITE),
140 inflight,
141 jiffies_to_msecs(part_stat_read(p, io_ticks)),
142 jiffies_to_msecs(part_stat_read(p, time_in_queue)),
143 part_stat_read(p, ios[STAT_DISCARD]),
144 part_stat_read(p, merges[STAT_DISCARD]),
145 (unsigned long long)part_stat_read(p, sectors[STAT_DISCARD]),
146 (unsigned int)part_stat_read_msecs(p, STAT_DISCARD));
147 }
148
149 ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
150 char *buf)
151 {
152 struct hd_struct *p = dev_to_part(dev);
153 struct request_queue *q = part_to_disk(p)->queue;
154 unsigned int inflight[2];
155
156 part_in_flight_rw(q, p, inflight);
157 return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);
158 }
159
160 #ifdef CONFIG_FAIL_MAKE_REQUEST
161 ssize_t part_fail_show(struct device *dev,
162 struct device_attribute *attr, char *buf)
163 {
164 struct hd_struct *p = dev_to_part(dev);
165
166 return sprintf(buf, "%d\n", p->make_it_fail);
167 }
168
169 ssize_t part_fail_store(struct device *dev,
170 struct device_attribute *attr,
171 const char *buf, size_t count)
172 {
173 struct hd_struct *p = dev_to_part(dev);
174 int i;
175
176 if (count > 0 && sscanf(buf, "%d", &i) > 0)
177 p->make_it_fail = (i == 0) ? 0 : 1;
178
179 return count;
180 }
181 #endif
182
183 static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
184 static DEVICE_ATTR(start, 0444, part_start_show, NULL);
185 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
186 static DEVICE_ATTR(ro, 0444, part_ro_show, NULL);
187 static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL);
188 static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL);
189 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
190 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
191 #ifdef CONFIG_FAIL_MAKE_REQUEST
192 static struct device_attribute dev_attr_fail =
193 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
194 #endif
195
196 static struct attribute *part_attrs[] = {
197 &dev_attr_partition.attr,
198 &dev_attr_start.attr,
199 &dev_attr_size.attr,
200 &dev_attr_ro.attr,
201 &dev_attr_alignment_offset.attr,
202 &dev_attr_discard_alignment.attr,
203 &dev_attr_stat.attr,
204 &dev_attr_inflight.attr,
205 #ifdef CONFIG_FAIL_MAKE_REQUEST
206 &dev_attr_fail.attr,
207 #endif
208 NULL
209 };
210
211 static struct attribute_group part_attr_group = {
212 .attrs = part_attrs,
213 };
214
215 static const struct attribute_group *part_attr_groups[] = {
216 &part_attr_group,
217 #ifdef CONFIG_BLK_DEV_IO_TRACE
218 &blk_trace_attr_group,
219 #endif
220 NULL
221 };
222
223 static void part_release(struct device *dev)
224 {
225 struct hd_struct *p = dev_to_part(dev);
226 blk_free_devt(dev->devt);
227 hd_free_part(p);
228 kfree(p);
229 }
230
231 static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
232 {
233 struct hd_struct *part = dev_to_part(dev);
234
235 add_uevent_var(env, "PARTN=%u", part->partno);
236 if (part->info && part->info->volname[0])
237 add_uevent_var(env, "PARTNAME=%s", part->info->volname);
238 return 0;
239 }
240
241 struct device_type part_type = {
242 .name = "partition",
243 .groups = part_attr_groups,
244 .release = part_release,
245 .uevent = part_uevent,
246 };
247
248 static void delete_partition_work_fn(struct work_struct *work)
249 {
250 struct hd_struct *part = container_of(to_rcu_work(work), struct hd_struct,
251 rcu_work);
252
253 part->start_sect = 0;
254 part->nr_sects = 0;
255 part_stat_set_all(part, 0);
256 put_device(part_to_dev(part));
257 }
258
259 void __delete_partition(struct percpu_ref *ref)
260 {
261 struct hd_struct *part = container_of(ref, struct hd_struct, ref);
262 INIT_RCU_WORK(&part->rcu_work, delete_partition_work_fn);
263 queue_rcu_work(system_wq, &part->rcu_work);
264 }
265
266 /*
267 * Must be called either with bd_mutex held, before a disk can be opened or
268 * after all disk users are gone.
269 */
270 void delete_partition(struct gendisk *disk, int partno)
271 {
272 struct disk_part_tbl *ptbl =
273 rcu_dereference_protected(disk->part_tbl, 1);
274 struct hd_struct *part;
275
276 if (partno >= ptbl->len)
277 return;
278
279 part = rcu_dereference_protected(ptbl->part[partno], 1);
280 if (!part)
281 return;
282
283 rcu_assign_pointer(ptbl->part[partno], NULL);
284 rcu_assign_pointer(ptbl->last_lookup, NULL);
285 kobject_put(part->holder_dir);
286 device_del(part_to_dev(part));
287
288 /*
289 * Remove gendisk pointer from idr so that it cannot be looked up
290 * while RCU period before freeing gendisk is running to prevent
291 * use-after-free issues. Note that the device number stays
292 * "in-use" until we really free the gendisk.
293 */
294 blk_invalidate_devt(part_devt(part));
295 hd_struct_kill(part);
296 }
297
298 static ssize_t whole_disk_show(struct device *dev,
299 struct device_attribute *attr, char *buf)
300 {
301 return 0;
302 }
303 static DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
304
305 /*
306 * Must be called either with bd_mutex held, before a disk can be opened or
307 * after all disk users are gone.
308 */
309 struct hd_struct *add_partition(struct gendisk *disk, int partno,
310 sector_t start, sector_t len, int flags,
311 struct partition_meta_info *info)
312 {
313 struct hd_struct *p;
314 dev_t devt = MKDEV(0, 0);
315 struct device *ddev = disk_to_dev(disk);
316 struct device *pdev;
317 struct disk_part_tbl *ptbl;
318 const char *dname;
319 int err;
320
321 err = disk_expand_part_tbl(disk, partno);
322 if (err)
323 return ERR_PTR(err);
324 ptbl = rcu_dereference_protected(disk->part_tbl, 1);
325
326 if (ptbl->part[partno])
327 return ERR_PTR(-EBUSY);
328
329 p = kzalloc(sizeof(*p), GFP_KERNEL);
330 if (!p)
331 return ERR_PTR(-EBUSY);
332
333 if (!init_part_stats(p)) {
334 err = -ENOMEM;
335 goto out_free;
336 }
337
338 seqcount_init(&p->nr_sects_seq);
339 pdev = part_to_dev(p);
340
341 p->start_sect = start;
342 p->alignment_offset =
343 queue_limit_alignment_offset(&disk->queue->limits, start);
344 p->discard_alignment =
345 queue_limit_discard_alignment(&disk->queue->limits, start);
346 p->nr_sects = len;
347 p->partno = partno;
348 p->policy = get_disk_ro(disk);
349
350 if (info) {
351 struct partition_meta_info *pinfo = alloc_part_info(disk);
352 if (!pinfo) {
353 err = -ENOMEM;
354 goto out_free_stats;
355 }
356 memcpy(pinfo, info, sizeof(*info));
357 p->info = pinfo;
358 }
359
360 dname = dev_name(ddev);
361 if (isdigit(dname[strlen(dname) - 1]))
362 dev_set_name(pdev, "%sp%d", dname, partno);
363 else
364 dev_set_name(pdev, "%s%d", dname, partno);
365
366 device_initialize(pdev);
367 pdev->class = &block_class;
368 pdev->type = &part_type;
369 pdev->parent = ddev;
370
371 err = blk_alloc_devt(p, &devt);
372 if (err)
373 goto out_free_info;
374 pdev->devt = devt;
375
376 /* delay uevent until 'holders' subdir is created */
377 dev_set_uevent_suppress(pdev, 1);
378 err = device_add(pdev);
379 if (err)
380 goto out_put;
381
382 err = -ENOMEM;
383 p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
384 if (!p->holder_dir)
385 goto out_del;
386
387 dev_set_uevent_suppress(pdev, 0);
388 if (flags & ADDPART_FLAG_WHOLEDISK) {
389 err = device_create_file(pdev, &dev_attr_whole_disk);
390 if (err)
391 goto out_del;
392 }
393
394 err = hd_ref_init(p);
395 if (err) {
396 if (flags & ADDPART_FLAG_WHOLEDISK)
397 goto out_remove_file;
398 goto out_del;
399 }
400
401 /* everything is up and running, commence */
402 rcu_assign_pointer(ptbl->part[partno], p);
403
404 /* suppress uevent if the disk suppresses it */
405 if (!dev_get_uevent_suppress(ddev))
406 kobject_uevent(&pdev->kobj, KOBJ_ADD);
407 return p;
408
409 out_free_info:
410 free_part_info(p);
411 out_free_stats:
412 free_part_stats(p);
413 out_free:
414 kfree(p);
415 return ERR_PTR(err);
416 out_remove_file:
417 device_remove_file(pdev, &dev_attr_whole_disk);
418 out_del:
419 kobject_put(p->holder_dir);
420 device_del(pdev);
421 out_put:
422 put_device(pdev);
423 return ERR_PTR(err);
424 }
425
426 static bool disk_unlock_native_capacity(struct gendisk *disk)
427 {
428 const struct block_device_operations *bdops = disk->fops;
429
430 if (bdops->unlock_native_capacity &&
431 !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
432 printk(KERN_CONT "enabling native capacity\n");
433 bdops->unlock_native_capacity(disk);
434 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
435 return true;
436 } else {
437 printk(KERN_CONT "truncated\n");
438 return false;
439 }
440 }
441
442 static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
443 {
444 struct disk_part_iter piter;
445 struct hd_struct *part;
446 int res;
447
448 if (bdev->bd_part_count || bdev->bd_super)
449 return -EBUSY;
450 res = invalidate_partition(disk, 0);
451 if (res)
452 return res;
453
454 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
455 while ((part = disk_part_iter_next(&piter)))
456 delete_partition(disk, part->partno);
457 disk_part_iter_exit(&piter);
458
459 return 0;
460 }
461
462 static bool part_zone_aligned(struct gendisk *disk,
463 struct block_device *bdev,
464 sector_t from, sector_t size)
465 {
466 unsigned int zone_sectors = bdev_zone_sectors(bdev);
467
468 /*
469 * If this function is called, then the disk is a zoned block device
470 * (host-aware or host-managed). This can be detected even if the
471 * zoned block device support is disabled (CONFIG_BLK_DEV_ZONED not
472 * set). In this case, however, only host-aware devices will be seen
473 * as a block device is not created for host-managed devices. Without
474 * zoned block device support, host-aware drives can still be used as
475 * regular block devices (no zone operation) and their zone size will
476 * be reported as 0. Allow this case.
477 */
478 if (!zone_sectors)
479 return true;
480
481 /*
482 * Check partition start and size alignement. If the drive has a
483 * smaller last runt zone, ignore it and allow the partition to
484 * use it. Check the zone size too: it should be a power of 2 number
485 * of sectors.
486 */
487 if (WARN_ON_ONCE(!is_power_of_2(zone_sectors))) {
488 u32 rem;
489
490 div_u64_rem(from, zone_sectors, &rem);
491 if (rem)
492 return false;
493 if ((from + size) < get_capacity(disk)) {
494 div_u64_rem(size, zone_sectors, &rem);
495 if (rem)
496 return false;
497 }
498
499 } else {
500
501 if (from & (zone_sectors - 1))
502 return false;
503 if ((from + size) < get_capacity(disk) &&
504 (size & (zone_sectors - 1)))
505 return false;
506
507 }
508
509 return true;
510 }
511
512 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
513 {
514 struct parsed_partitions *state = NULL;
515 struct hd_struct *part;
516 int p, highest, res;
517 rescan:
518 if (state && !IS_ERR(state)) {
519 free_partitions(state);
520 state = NULL;
521 }
522
523 res = drop_partitions(disk, bdev);
524 if (res)
525 return res;
526
527 if (disk->fops->revalidate_disk)
528 disk->fops->revalidate_disk(disk);
529 check_disk_size_change(disk, bdev, true);
530 bdev->bd_invalidated = 0;
531 if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
532 return 0;
533 if (IS_ERR(state)) {
534 /*
535 * I/O error reading the partition table. If any
536 * partition code tried to read beyond EOD, retry
537 * after unlocking native capacity.
538 */
539 if (PTR_ERR(state) == -ENOSPC) {
540 printk(KERN_WARNING "%s: partition table beyond EOD, ",
541 disk->disk_name);
542 if (disk_unlock_native_capacity(disk))
543 goto rescan;
544 }
545 return -EIO;
546 }
547 /*
548 * If any partition code tried to read beyond EOD, try
549 * unlocking native capacity even if partition table is
550 * successfully read as we could be missing some partitions.
551 */
552 if (state->access_beyond_eod) {
553 printk(KERN_WARNING
554 "%s: partition table partially beyond EOD, ",
555 disk->disk_name);
556 if (disk_unlock_native_capacity(disk))
557 goto rescan;
558 }
559
560 /* tell userspace that the media / partition table may have changed */
561 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
562
563 /* Detect the highest partition number and preallocate
564 * disk->part_tbl. This is an optimization and not strictly
565 * necessary.
566 */
567 for (p = 1, highest = 0; p < state->limit; p++)
568 if (state->parts[p].size)
569 highest = p;
570
571 disk_expand_part_tbl(disk, highest);
572
573 /* add partitions */
574 for (p = 1; p < state->limit; p++) {
575 sector_t size, from;
576
577 size = state->parts[p].size;
578 if (!size)
579 continue;
580
581 from = state->parts[p].from;
582 if (from >= get_capacity(disk)) {
583 printk(KERN_WARNING
584 "%s: p%d start %llu is beyond EOD, ",
585 disk->disk_name, p, (unsigned long long) from);
586 if (disk_unlock_native_capacity(disk))
587 goto rescan;
588 continue;
589 }
590
591 if (from + size > get_capacity(disk)) {
592 printk(KERN_WARNING
593 "%s: p%d size %llu extends beyond EOD, ",
594 disk->disk_name, p, (unsigned long long) size);
595
596 if (disk_unlock_native_capacity(disk)) {
597 /* free state and restart */
598 goto rescan;
599 } else {
600 /*
601 * we can not ignore partitions of broken tables
602 * created by for example camera firmware, but
603 * we limit them to the end of the disk to avoid
604 * creating invalid block devices
605 */
606 size = get_capacity(disk) - from;
607 }
608 }
609
610 /*
611 * On a zoned block device, partitions should be aligned on the
612 * device zone size (i.e. zone boundary crossing not allowed).
613 * Otherwise, resetting the write pointer of the last zone of
614 * one partition may impact the following partition.
615 */
616 if (bdev_is_zoned(bdev) &&
617 !part_zone_aligned(disk, bdev, from, size)) {
618 printk(KERN_WARNING
619 "%s: p%d start %llu+%llu is not zone aligned\n",
620 disk->disk_name, p, (unsigned long long) from,
621 (unsigned long long) size);
622 continue;
623 }
624
625 part = add_partition(disk, p, from, size,
626 state->parts[p].flags,
627 &state->parts[p].info);
628 if (IS_ERR(part)) {
629 printk(KERN_ERR " %s: p%d could not be added: %ld\n",
630 disk->disk_name, p, -PTR_ERR(part));
631 continue;
632 }
633 #ifdef CONFIG_BLK_DEV_MD
634 if (state->parts[p].flags & ADDPART_FLAG_RAID)
635 md_autodetect_dev(part_to_dev(part)->devt);
636 #endif
637 }
638 free_partitions(state);
639 return 0;
640 }
641
642 int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
643 {
644 int res;
645
646 if (!bdev->bd_invalidated)
647 return 0;
648
649 res = drop_partitions(disk, bdev);
650 if (res)
651 return res;
652
653 set_capacity(disk, 0);
654 check_disk_size_change(disk, bdev, false);
655 bdev->bd_invalidated = 0;
656 /* tell userspace that the media / partition table may have changed */
657 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
658
659 return 0;
660 }
661
662 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
663 {
664 struct address_space *mapping = bdev->bd_inode->i_mapping;
665 struct page *page;
666
667 page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_SHIFT-9)), NULL);
668 if (!IS_ERR(page)) {
669 if (PageError(page))
670 goto fail;
671 p->v = page;
672 return (unsigned char *)page_address(page) + ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << 9);
673 fail:
674 put_page(page);
675 }
676 p->v = NULL;
677 return NULL;
678 }
679
680 EXPORT_SYMBOL(read_dev_sector);
681
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