1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 1991-1998 Linus Torvalds
4 * Re-organised Feb 1998 Russell King
5 * Copyright (C) 2020 Christoph Hellwig
6 */
7 #include <linux/fs.h>
8 #include <linux/major.h>
9 #include <linux/slab.h>
10 #include <linux/ctype.h>
11 #include <linux/vmalloc.h>
12 #include <linux/raid/detect.h>
13 #include "check.h"
14
15 static int (*const check_part[])(struct parsed_partitions *) = {
16 /*
17 * Probe partition formats with tables at disk address 0
18 * that also have an ADFS boot block at 0xdc0.
19 */
20 #ifdef CONFIG_ACORN_PARTITION_ICS
21 adfspart_check_ICS,
22 #endif
23 #ifdef CONFIG_ACORN_PARTITION_POWERTEC
24 adfspart_check_POWERTEC,
25 #endif
26 #ifdef CONFIG_ACORN_PARTITION_EESOX
27 adfspart_check_EESOX,
28 #endif
29
30 /*
31 * Now move on to formats that only have partition info at
32 * disk address 0xdc0. Since these may also have stale
33 * PC/BIOS partition tables, they need to come before
34 * the msdos entry.
35 */
36 #ifdef CONFIG_ACORN_PARTITION_CUMANA
37 adfspart_check_CUMANA,
38 #endif
39 #ifdef CONFIG_ACORN_PARTITION_ADFS
40 adfspart_check_ADFS,
41 #endif
42
43 #ifdef CONFIG_CMDLINE_PARTITION
44 cmdline_partition,
45 #endif
46 #ifdef CONFIG_EFI_PARTITION
47 efi_partition, /* this must come before msdos */
48 #endif
49 #ifdef CONFIG_SGI_PARTITION
50 sgi_partition,
51 #endif
52 #ifdef CONFIG_LDM_PARTITION
53 ldm_partition, /* this must come before msdos */
54 #endif
55 #ifdef CONFIG_MSDOS_PARTITION
56 msdos_partition,
57 #endif
58 #ifdef CONFIG_OSF_PARTITION
59 osf_partition,
60 #endif
61 #ifdef CONFIG_SUN_PARTITION
62 sun_partition,
63 #endif
64 #ifdef CONFIG_AMIGA_PARTITION
65 amiga_partition,
66 #endif
67 #ifdef CONFIG_ATARI_PARTITION
68 atari_partition,
69 #endif
70 #ifdef CONFIG_MAC_PARTITION
71 mac_partition,
72 #endif
73 #ifdef CONFIG_ULTRIX_PARTITION
74 ultrix_partition,
75 #endif
76 #ifdef CONFIG_IBM_PARTITION
77 ibm_partition,
78 #endif
79 #ifdef CONFIG_KARMA_PARTITION
80 karma_partition,
81 #endif
82 #ifdef CONFIG_SYSV68_PARTITION
83 sysv68_partition,
84 #endif
85 NULL
86 };
87
88 static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
89 {
90 struct parsed_partitions *state;
91 int nr = DISK_MAX_PARTS;
92
93 state = kzalloc(sizeof(*state), GFP_KERNEL);
94 if (!state)
95 return NULL;
96
97 state->parts = vzalloc(array_size(nr, sizeof(state->parts[0])));
98 if (!state->parts) {
99 kfree(state);
100 return NULL;
101 }
102
103 state->limit = nr;
104
105 return state;
106 }
107
108 static void free_partitions(struct parsed_partitions *state)
109 {
110 vfree(state->parts);
111 kfree(state);
112 }
113
114 static struct parsed_partitions *check_partition(struct gendisk *hd)
115 {
116 struct parsed_partitions *state;
117 int i, res, err;
118
119 state = allocate_partitions(hd);
120 if (!state)
121 return NULL;
122 state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
123 if (!state->pp_buf) {
124 free_partitions(state);
125 return NULL;
126 }
127 state->pp_buf[0] = '\0';
128
129 state->disk = hd;
130 snprintf(state->name, BDEVNAME_SIZE, "%s", hd->disk_name);
131 snprintf(state->pp_buf, PAGE_SIZE, " %s:", state->name);
132 if (isdigit(state->name[strlen(state->name)-1]))
133 sprintf(state->name, "p");
134
135 i = res = err = 0;
136 while (!res && check_part[i]) {
137 memset(state->parts, 0, state->limit * sizeof(state->parts[0]));
138 res = check_part[i++](state);
139 if (res < 0) {
140 /*
141 * We have hit an I/O error which we don't report now.
142 * But record it, and let the others do their job.
143 */
144 err = res;
145 res = 0;
146 }
147
148 }
149 if (res > 0) {
150 printk(KERN_INFO "%s", state->pp_buf);
151
152 free_page((unsigned long)state->pp_buf);
153 return state;
154 }
155 if (state->access_beyond_eod)
156 err = -ENOSPC;
157 /*
158 * The partition is unrecognized. So report I/O errors if there were any
159 */
160 if (err)
161 res = err;
162 if (res) {
163 strlcat(state->pp_buf,
164 " unable to read partition table\n", PAGE_SIZE);
165 printk(KERN_INFO "%s", state->pp_buf);
166 }
167
168 free_page((unsigned long)state->pp_buf);
169 free_partitions(state);
170 return ERR_PTR(res);
171 }
172
173 static ssize_t part_partition_show(struct device *dev,
174 struct device_attribute *attr, char *buf)
175 {
176 return sprintf(buf, "%d\n", bdev_partno(dev_to_bdev(dev)));
177 }
178
179 static ssize_t part_start_show(struct device *dev,
180 struct device_attribute *attr, char *buf)
181 {
182 return sprintf(buf, "%llu\n", dev_to_bdev(dev)->bd_start_sect);
183 }
184
185 static ssize_t part_ro_show(struct device *dev,
186 struct device_attribute *attr, char *buf)
187 {
188 return sprintf(buf, "%d\n", bdev_read_only(dev_to_bdev(dev)));
189 }
190
191 static ssize_t part_alignment_offset_show(struct device *dev,
192 struct device_attribute *attr, char *buf)
193 {
194 return sprintf(buf, "%u\n", bdev_alignment_offset(dev_to_bdev(dev)));
195 }
196
197 static ssize_t part_discard_alignment_show(struct device *dev,
198 struct device_attribute *attr, char *buf)
199 {
200 return sprintf(buf, "%u\n", bdev_discard_alignment(dev_to_bdev(dev)));
201 }
202
203 static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
204 static DEVICE_ATTR(start, 0444, part_start_show, NULL);
205 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
206 static DEVICE_ATTR(ro, 0444, part_ro_show, NULL);
207 static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL);
208 static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL);
209 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
210 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
211 #ifdef CONFIG_FAIL_MAKE_REQUEST
212 static struct device_attribute dev_attr_fail =
213 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
214 #endif
215
216 static struct attribute *part_attrs[] = {
217 &dev_attr_partition.attr,
218 &dev_attr_start.attr,
219 &dev_attr_size.attr,
220 &dev_attr_ro.attr,
221 &dev_attr_alignment_offset.attr,
222 &dev_attr_discard_alignment.attr,
223 &dev_attr_stat.attr,
224 &dev_attr_inflight.attr,
225 #ifdef CONFIG_FAIL_MAKE_REQUEST
226 &dev_attr_fail.attr,
227 #endif
228 NULL
229 };
230
231 static const struct attribute_group part_attr_group = {
232 .attrs = part_attrs,
233 };
234
235 static const struct attribute_group *part_attr_groups[] = {
236 &part_attr_group,
237 #ifdef CONFIG_BLK_DEV_IO_TRACE
238 &blk_trace_attr_group,
239 #endif
240 NULL
241 };
242
243 static void part_release(struct device *dev)
244 {
245 put_disk(dev_to_bdev(dev)->bd_disk);
246 bdev_drop(dev_to_bdev(dev));
247 }
248
249 static int part_uevent(const struct device *dev, struct kobj_uevent_env *env)
250 {
251 const struct block_device *part = dev_to_bdev(dev);
252
253 add_uevent_var(env, "PARTN=%u", bdev_partno(part));
254 if (part->bd_meta_info && part->bd_meta_info->volname[0])
255 add_uevent_var(env, "PARTNAME=%s", part->bd_meta_info->volname);
256 return 0;
257 }
258
259 const struct device_type part_type = {
260 .name = "partition",
261 .groups = part_attr_groups,
262 .release = part_release,
263 .uevent = part_uevent,
264 };
265
266 void drop_partition(struct block_device *part)
267 {
268 lockdep_assert_held(&part->bd_disk->open_mutex);
269
270 xa_erase(&part->bd_disk->part_tbl, bdev_partno(part));
271 kobject_put(part->bd_holder_dir);
272
273 device_del(&part->bd_device);
274 put_device(&part->bd_device);
275 }
276
277 static ssize_t whole_disk_show(struct device *dev,
278 struct device_attribute *attr, char *buf)
279 {
280 return 0;
281 }
282 static const DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
283
284 /*
285 * Must be called either with open_mutex held, before a disk can be opened or
286 * after all disk users are gone.
287 */
288 static struct block_device *add_partition(struct gendisk *disk, int partno,
289 sector_t start, sector_t len, int flags,
290 struct partition_meta_info *info)
291 {
292 dev_t devt = MKDEV(0, 0);
293 struct device *ddev = disk_to_dev(disk);
294 struct device *pdev;
295 struct block_device *bdev;
296 const char *dname;
297 int err;
298
299 lockdep_assert_held(&disk->open_mutex);
300
301 if (partno >= DISK_MAX_PARTS)
302 return ERR_PTR(-EINVAL);
303
304 /*
305 * Partitions are not supported on zoned block devices that are used as
306 * such.
307 */
308 if (bdev_is_zoned(disk->part0)) {
309 pr_warn("%s: partitions not supported on host managed zoned block device\n",
310 disk->disk_name);
311 return ERR_PTR(-ENXIO);
312 }
313
314 if (xa_load(&disk->part_tbl, partno))
315 return ERR_PTR(-EBUSY);
316
317 /* ensure we always have a reference to the whole disk */
318 get_device(disk_to_dev(disk));
319
320 err = -ENOMEM;
321 bdev = bdev_alloc(disk, partno);
322 if (!bdev)
323 goto out_put_disk;
324
325 bdev->bd_start_sect = start;
326 bdev_set_nr_sectors(bdev, len);
327
328 pdev = &bdev->bd_device;
329 dname = dev_name(ddev);
330 if (isdigit(dname[strlen(dname) - 1]))
331 dev_set_name(pdev, "%sp%d", dname, partno);
332 else
333 dev_set_name(pdev, "%s%d", dname, partno);
334
335 device_initialize(pdev);
336 pdev->class = &block_class;
337 pdev->type = &part_type;
338 pdev->parent = ddev;
339
340 /* in consecutive minor range? */
341 if (bdev_partno(bdev) < disk->minors) {
342 devt = MKDEV(disk->major, disk->first_minor + bdev_partno(bdev));
343 } else {
344 err = blk_alloc_ext_minor();
345 if (err < 0)
346 goto out_put;
347 devt = MKDEV(BLOCK_EXT_MAJOR, err);
348 }
349 pdev->devt = devt;
350
351 if (info) {
352 err = -ENOMEM;
353 bdev->bd_meta_info = kmemdup(info, sizeof(*info), GFP_KERNEL);
354 if (!bdev->bd_meta_info)
355 goto out_put;
356 }
357
358 /* delay uevent until 'holders' subdir is created */
359 dev_set_uevent_suppress(pdev, 1);
360 err = device_add(pdev);
361 if (err)
362 goto out_put;
363
364 err = -ENOMEM;
365 bdev->bd_holder_dir = kobject_create_and_add("holders", &pdev->kobj);
366 if (!bdev->bd_holder_dir)
367 goto out_del;
368
369 dev_set_uevent_suppress(pdev, 0);
370 if (flags & ADDPART_FLAG_WHOLEDISK) {
371 err = device_create_file(pdev, &dev_attr_whole_disk);
372 if (err)
373 goto out_del;
374 }
375
376 /* everything is up and running, commence */
377 err = xa_insert(&disk->part_tbl, partno, bdev, GFP_KERNEL);
378 if (err)
379 goto out_del;
380 bdev_add(bdev, devt);
381
382 /* suppress uevent if the disk suppresses it */
383 if (!dev_get_uevent_suppress(ddev))
384 kobject_uevent(&pdev->kobj, KOBJ_ADD);
385 return bdev;
386
387 out_del:
388 kobject_put(bdev->bd_holder_dir);
389 device_del(pdev);
390 out_put:
391 put_device(pdev);
392 return ERR_PTR(err);
393 out_put_disk:
394 put_disk(disk);
395 return ERR_PTR(err);
396 }
397
398 static bool partition_overlaps(struct gendisk *disk, sector_t start,
399 sector_t length, int skip_partno)
400 {
401 struct block_device *part;
402 bool overlap = false;
403 unsigned long idx;
404
405 rcu_read_lock();
406 xa_for_each_start(&disk->part_tbl, idx, part, 1) {
407 if (bdev_partno(part) != skip_partno &&
408 start < part->bd_start_sect + bdev_nr_sectors(part) &&
409 start + length > part->bd_start_sect) {
410 overlap = true;
411 break;
412 }
413 }
414 rcu_read_unlock();
415
416 return overlap;
417 }
418
419 int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
420 sector_t length)
421 {
422 struct block_device *part;
423 int ret;
424
425 mutex_lock(&disk->open_mutex);
426 if (!disk_live(disk)) {
427 ret = -ENXIO;
428 goto out;
429 }
430
431 if (disk->flags & GENHD_FL_NO_PART) {
432 ret = -EINVAL;
433 goto out;
434 }
435
436 if (partition_overlaps(disk, start, length, -1)) {
437 ret = -EBUSY;
438 goto out;
439 }
440
441 part = add_partition(disk, partno, start, length,
442 ADDPART_FLAG_NONE, NULL);
443 ret = PTR_ERR_OR_ZERO(part);
444 out:
445 mutex_unlock(&disk->open_mutex);
446 return ret;
447 }
448
449 int bdev_del_partition(struct gendisk *disk, int partno)
450 {
451 struct block_device *part = NULL;
452 int ret = -ENXIO;
453
454 mutex_lock(&disk->open_mutex);
455 part = xa_load(&disk->part_tbl, partno);
456 if (!part)
457 goto out_unlock;
458
459 ret = -EBUSY;
460 if (atomic_read(&part->bd_openers))
461 goto out_unlock;
462
463 /*
464 * We verified that @part->bd_openers is zero above and so
465 * @part->bd_holder{_ops} can't be set. And since we hold
466 * @disk->open_mutex the device can't be claimed by anyone.
467 *
468 * So no need to call @part->bd_holder_ops->mark_dead() here.
469 * Just delete the partition and invalidate it.
470 */
471
472 bdev_unhash(part);
473 invalidate_bdev(part);
474 drop_partition(part);
475 ret = 0;
476 out_unlock:
477 mutex_unlock(&disk->open_mutex);
478 return ret;
479 }
480
481 int bdev_resize_partition(struct gendisk *disk, int partno, sector_t start,
482 sector_t length)
483 {
484 struct block_device *part = NULL;
485 int ret = -ENXIO;
486
487 mutex_lock(&disk->open_mutex);
488 part = xa_load(&disk->part_tbl, partno);
489 if (!part)
490 goto out_unlock;
491
492 ret = -EINVAL;
493 if (start != part->bd_start_sect)
494 goto out_unlock;
495
496 ret = -EBUSY;
497 if (partition_overlaps(disk, start, length, partno))
498 goto out_unlock;
499
500 bdev_set_nr_sectors(part, length);
501
502 ret = 0;
503 out_unlock:
504 mutex_unlock(&disk->open_mutex);
505 return ret;
506 }
507
508 static bool disk_unlock_native_capacity(struct gendisk *disk)
509 {
510 if (!disk->fops->unlock_native_capacity ||
511 test_and_set_bit(GD_NATIVE_CAPACITY, &disk->state)) {
512 printk(KERN_CONT "truncated\n");
513 return false;
514 }
515
516 printk(KERN_CONT "enabling native capacity\n");
517 disk->fops->unlock_native_capacity(disk);
518 return true;
519 }
520
521 static bool blk_add_partition(struct gendisk *disk,
522 struct parsed_partitions *state, int p)
523 {
524 sector_t size = state->parts[p].size;
525 sector_t from = state->parts[p].from;
526 struct block_device *part;
527
528 if (!size)
529 return true;
530
531 if (from >= get_capacity(disk)) {
532 printk(KERN_WARNING
533 "%s: p%d start %llu is beyond EOD, ",
534 disk->disk_name, p, (unsigned long long) from);
535 if (disk_unlock_native_capacity(disk))
536 return false;
537 return true;
538 }
539
540 if (from + size > get_capacity(disk)) {
541 printk(KERN_WARNING
542 "%s: p%d size %llu extends beyond EOD, ",
543 disk->disk_name, p, (unsigned long long) size);
544
545 if (disk_unlock_native_capacity(disk))
546 return false;
547
548 /*
549 * We can not ignore partitions of broken tables created by for
550 * example camera firmware, but we limit them to the end of the
551 * disk to avoid creating invalid block devices.
552 */
553 size = get_capacity(disk) - from;
554 }
555
556 part = add_partition(disk, p, from, size, state->parts[p].flags,
557 &state->parts[p].info);
558 if (IS_ERR(part)) {
559 if (PTR_ERR(part) != -ENXIO) {
560 printk(KERN_ERR " %s: p%d could not be added: %pe\n",
561 disk->disk_name, p, part);
562 }
563 return true;
564 }
565
566 if (IS_BUILTIN(CONFIG_BLK_DEV_MD) &&
567 (state->parts[p].flags & ADDPART_FLAG_RAID))
568 md_autodetect_dev(part->bd_dev);
569
570 return true;
571 }
572
573 static int blk_add_partitions(struct gendisk *disk)
574 {
575 struct parsed_partitions *state;
576 int ret = -EAGAIN, p;
577
578 if (!disk_has_partscan(disk))
579 return 0;
580
581 state = check_partition(disk);
582 if (!state)
583 return 0;
584 if (IS_ERR(state)) {
585 /*
586 * I/O error reading the partition table. If we tried to read
587 * beyond EOD, retry after unlocking the native capacity.
588 */
589 if (PTR_ERR(state) == -ENOSPC) {
590 printk(KERN_WARNING "%s: partition table beyond EOD, ",
591 disk->disk_name);
592 if (disk_unlock_native_capacity(disk))
593 return -EAGAIN;
594 }
595 return -EIO;
596 }
597
598 /*
599 * Partitions are not supported on host managed zoned block devices.
600 */
601 if (bdev_is_zoned(disk->part0)) {
602 pr_warn("%s: ignoring partition table on host managed zoned block device\n",
603 disk->disk_name);
604 ret = 0;
605 goto out_free_state;
606 }
607
608 /*
609 * If we read beyond EOD, try unlocking native capacity even if the
610 * partition table was successfully read as we could be missing some
611 * partitions.
612 */
613 if (state->access_beyond_eod) {
614 printk(KERN_WARNING
615 "%s: partition table partially beyond EOD, ",
616 disk->disk_name);
617 if (disk_unlock_native_capacity(disk))
618 goto out_free_state;
619 }
620
621 /* tell userspace that the media / partition table may have changed */
622 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
623
624 for (p = 1; p < state->limit; p++)
625 if (!blk_add_partition(disk, state, p))
626 goto out_free_state;
627
628 ret = 0;
629 out_free_state:
630 free_partitions(state);
631 return ret;
632 }
633
634 int bdev_disk_changed(struct gendisk *disk, bool invalidate)
635 {
636 struct block_device *part;
637 unsigned long idx;
638 int ret = 0;
639
640 lockdep_assert_held(&disk->open_mutex);
641
642 if (!disk_live(disk))
643 return -ENXIO;
644
645 rescan:
646 if (disk->open_partitions)
647 return -EBUSY;
648 sync_blockdev(disk->part0);
649 invalidate_bdev(disk->part0);
650
651 xa_for_each_start(&disk->part_tbl, idx, part, 1) {
652 /*
653 * Remove the block device from the inode hash, so that
654 * it cannot be looked up any more even when openers
655 * still hold references.
656 */
657 bdev_unhash(part);
658
659 /*
660 * If @disk->open_partitions isn't elevated but there's
661 * still an active holder of that block device things
662 * are broken.
663 */
664 WARN_ON_ONCE(atomic_read(&part->bd_openers));
665 invalidate_bdev(part);
666 drop_partition(part);
667 }
668 clear_bit(GD_NEED_PART_SCAN, &disk->state);
669
670 /*
671 * Historically we only set the capacity to zero for devices that
672 * support partitions (independ of actually having partitions created).
673 * Doing that is rather inconsistent, but changing it broke legacy
674 * udisks polling for legacy ide-cdrom devices. Use the crude check
675 * below to get the sane behavior for most device while not breaking
676 * userspace for this particular setup.
677 */
678 if (invalidate) {
679 if (!(disk->flags & GENHD_FL_NO_PART) ||
680 !(disk->flags & GENHD_FL_REMOVABLE))
681 set_capacity(disk, 0);
682 }
683
684 if (get_capacity(disk)) {
685 ret = blk_add_partitions(disk);
686 if (ret == -EAGAIN)
687 goto rescan;
688 } else if (invalidate) {
689 /*
690 * Tell userspace that the media / partition table may have
691 * changed.
692 */
693 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
694 }
695
696 return ret;
697 }
698 /*
699 * Only exported for loop and dasd for historic reasons. Don't use in new
700 * code!
701 */
702 EXPORT_SYMBOL_GPL(bdev_disk_changed);
703
704 void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
705 {
706 struct address_space *mapping = state->disk->part0->bd_mapping;
707 struct folio *folio;
708
709 if (n >= get_capacity(state->disk)) {
710 state->access_beyond_eod = true;
711 goto out;
712 }
713
714 folio = read_mapping_folio(mapping, n >> PAGE_SECTORS_SHIFT, NULL);
715 if (IS_ERR(folio))
716 goto out;
717
718 p->v = folio;
719 return folio_address(folio) + offset_in_folio(folio, n * SECTOR_SIZE);
720 out:
721 p->v = NULL;
722 return NULL;
723 }
724
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