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
15static 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_OF_PARTITION
47 of_partition, /* cmdline have priority to OF */
48#endif
49#ifdef CONFIG_EFI_PARTITION
50 efi_partition, /* this must come before msdos */
51#endif
52#ifdef CONFIG_SGI_PARTITION
53 sgi_partition,
54#endif
55#ifdef CONFIG_LDM_PARTITION
56 ldm_partition, /* this must come before msdos */
57#endif
58#ifdef CONFIG_MSDOS_PARTITION
59 msdos_partition,
60#endif
61#ifdef CONFIG_OSF_PARTITION
62 osf_partition,
63#endif
64#ifdef CONFIG_SUN_PARTITION
65 sun_partition,
66#endif
67#ifdef CONFIG_AMIGA_PARTITION
68 amiga_partition,
69#endif
70#ifdef CONFIG_ATARI_PARTITION
71 atari_partition,
72#endif
73#ifdef CONFIG_MAC_PARTITION
74 mac_partition,
75#endif
76#ifdef CONFIG_ULTRIX_PARTITION
77 ultrix_partition,
78#endif
79#ifdef CONFIG_IBM_PARTITION
80 ibm_partition,
81#endif
82#ifdef CONFIG_KARMA_PARTITION
83 karma_partition,
84#endif
85#ifdef CONFIG_SYSV68_PARTITION
86 sysv68_partition,
87#endif
88 NULL
89};
90
91static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
92{
93 struct parsed_partitions *state;
94 int nr = DISK_MAX_PARTS;
95
96 state = kzalloc(sizeof(*state), GFP_KERNEL);
97 if (!state)
98 return NULL;
99
100 state->parts = vzalloc(array_size(nr, sizeof(state->parts[0])));
101 if (!state->parts) {
102 kfree(objp: state);
103 return NULL;
104 }
105
106 state->limit = nr;
107
108 return state;
109}
110
111static void free_partitions(struct parsed_partitions *state)
112{
113 vfree(addr: state->parts);
114 kfree(objp: state);
115}
116
117static struct parsed_partitions *check_partition(struct gendisk *hd)
118{
119 struct parsed_partitions *state;
120 int i, res, err;
121
122 state = allocate_partitions(hd);
123 if (!state)
124 return NULL;
125 state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
126 if (!state->pp_buf) {
127 free_partitions(state);
128 return NULL;
129 }
130 state->pp_buf[0] = '\0';
131
132 state->disk = hd;
133 snprintf(buf: state->name, BDEVNAME_SIZE, fmt: "%s", hd->disk_name);
134 snprintf(buf: state->pp_buf, PAGE_SIZE, fmt: " %s:", state->name);
135 if (isdigit(c: state->name[strlen(state->name)-1]))
136 sprintf(buf: state->name, fmt: "p");
137
138 i = res = err = 0;
139 while (!res && check_part[i]) {
140 memset(s: state->parts, c: 0, n: state->limit * sizeof(state->parts[0]));
141 res = check_part[i++](state);
142 if (res < 0) {
143 /*
144 * We have hit an I/O error which we don't report now.
145 * But record it, and let the others do their job.
146 */
147 err = res;
148 res = 0;
149 }
150
151 }
152 if (res > 0) {
153 printk(KERN_INFO "%s", state->pp_buf);
154
155 free_page((unsigned long)state->pp_buf);
156 return state;
157 }
158 if (state->access_beyond_eod)
159 err = -ENOSPC;
160 /*
161 * The partition is unrecognized. So report I/O errors if there were any
162 */
163 if (err)
164 res = err;
165 if (res) {
166 strlcat(state->pp_buf,
167 " unable to read partition table\n", PAGE_SIZE);
168 printk(KERN_INFO "%s", state->pp_buf);
169 }
170
171 free_page((unsigned long)state->pp_buf);
172 free_partitions(state);
173 return ERR_PTR(error: res);
174}
175
176static ssize_t part_partition_show(struct device *dev,
177 struct device_attribute *attr, char *buf)
178{
179 return sprintf(buf, fmt: "%d\n", bdev_partno(dev_to_bdev(dev)));
180}
181
182static ssize_t part_start_show(struct device *dev,
183 struct device_attribute *attr, char *buf)
184{
185 return sprintf(buf, fmt: "%llu\n", dev_to_bdev(dev)->bd_start_sect);
186}
187
188static ssize_t part_ro_show(struct device *dev,
189 struct device_attribute *attr, char *buf)
190{
191 return sprintf(buf, fmt: "%d\n", bdev_read_only(dev_to_bdev(dev)));
192}
193
194static ssize_t part_alignment_offset_show(struct device *dev,
195 struct device_attribute *attr, char *buf)
196{
197 return sprintf(buf, fmt: "%u\n", bdev_alignment_offset(dev_to_bdev(dev)));
198}
199
200static ssize_t part_discard_alignment_show(struct device *dev,
201 struct device_attribute *attr, char *buf)
202{
203 return sprintf(buf, fmt: "%u\n", bdev_discard_alignment(dev_to_bdev(dev)));
204}
205
206static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
207static DEVICE_ATTR(start, 0444, part_start_show, NULL);
208static DEVICE_ATTR(size, 0444, part_size_show, NULL);
209static DEVICE_ATTR(ro, 0444, part_ro_show, NULL);
210static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL);
211static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL);
212static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
213static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
214#ifdef CONFIG_FAIL_MAKE_REQUEST
215static struct device_attribute dev_attr_fail =
216 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
217#endif
218
219static struct attribute *part_attrs[] = {
220 &dev_attr_partition.attr,
221 &dev_attr_start.attr,
222 &dev_attr_size.attr,
223 &dev_attr_ro.attr,
224 &dev_attr_alignment_offset.attr,
225 &dev_attr_discard_alignment.attr,
226 &dev_attr_stat.attr,
227 &dev_attr_inflight.attr,
228#ifdef CONFIG_FAIL_MAKE_REQUEST
229 &dev_attr_fail.attr,
230#endif
231 NULL
232};
233
234static const struct attribute_group part_attr_group = {
235 .attrs = part_attrs,
236};
237
238static const struct attribute_group *part_attr_groups[] = {
239 &part_attr_group,
240#ifdef CONFIG_BLK_DEV_IO_TRACE
241 &blk_trace_attr_group,
242#endif
243 NULL
244};
245
246static void part_release(struct device *dev)
247{
248 put_disk(dev_to_bdev(dev)->bd_disk);
249 bdev_drop(dev_to_bdev(dev));
250}
251
252static int part_uevent(const struct device *dev, struct kobj_uevent_env *env)
253{
254 const struct block_device *part = dev_to_bdev(dev);
255
256 add_uevent_var(env, format: "PARTN=%u", bdev_partno(bdev: part));
257 if (part->bd_meta_info && part->bd_meta_info->volname[0])
258 add_uevent_var(env, format: "PARTNAME=%s", part->bd_meta_info->volname);
259 if (part->bd_meta_info && part->bd_meta_info->uuid[0])
260 add_uevent_var(env, format: "PARTUUID=%s", part->bd_meta_info->uuid);
261 return 0;
262}
263
264const struct device_type part_type = {
265 .name = "partition",
266 .groups = part_attr_groups,
267 .release = part_release,
268 .uevent = part_uevent,
269};
270
271void drop_partition(struct block_device *part)
272{
273 lockdep_assert_held(&part->bd_disk->open_mutex);
274
275 xa_erase(&part->bd_disk->part_tbl, index: bdev_partno(bdev: part));
276 kobject_put(kobj: part->bd_holder_dir);
277
278 device_del(dev: &part->bd_device);
279 put_device(dev: &part->bd_device);
280}
281
282static ssize_t whole_disk_show(struct device *dev,
283 struct device_attribute *attr, char *buf)
284{
285 return 0;
286}
287static const DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
288
289/*
290 * Must be called either with open_mutex held, before a disk can be opened or
291 * after all disk users are gone.
292 */
293static struct block_device *add_partition(struct gendisk *disk, int partno,
294 sector_t start, sector_t len, int flags,
295 struct partition_meta_info *info)
296{
297 dev_t devt = MKDEV(0, 0);
298 struct device *ddev = disk_to_dev(disk);
299 struct device *pdev;
300 struct block_device *bdev;
301 const char *dname;
302 int err;
303
304 lockdep_assert_held(&disk->open_mutex);
305
306 if (partno >= DISK_MAX_PARTS)
307 return ERR_PTR(error: -EINVAL);
308
309 /*
310 * Partitions are not supported on zoned block devices that are used as
311 * such.
312 */
313 if (bdev_is_zoned(bdev: disk->part0)) {
314 pr_warn("%s: partitions not supported on host managed zoned block device\n",
315 disk->disk_name);
316 return ERR_PTR(error: -ENXIO);
317 }
318
319 if (xa_load(&disk->part_tbl, index: partno))
320 return ERR_PTR(error: -EBUSY);
321
322 /* ensure we always have a reference to the whole disk */
323 get_device(disk_to_dev(disk));
324
325 err = -ENOMEM;
326 bdev = bdev_alloc(disk, partno);
327 if (!bdev)
328 goto out_put_disk;
329
330 bdev->bd_start_sect = start;
331 bdev_set_nr_sectors(bdev, sectors: len);
332
333 pdev = &bdev->bd_device;
334 dname = dev_name(dev: ddev);
335 if (isdigit(c: dname[strlen(dname) - 1]))
336 dev_set_name(dev: pdev, name: "%sp%d", dname, partno);
337 else
338 dev_set_name(dev: pdev, name: "%s%d", dname, partno);
339
340 device_initialize(dev: pdev);
341 pdev->class = &block_class;
342 pdev->type = &part_type;
343 pdev->parent = ddev;
344
345 /* in consecutive minor range? */
346 if (bdev_partno(bdev) < disk->minors) {
347 devt = MKDEV(disk->major, disk->first_minor + bdev_partno(bdev));
348 } else {
349 err = blk_alloc_ext_minor();
350 if (err < 0)
351 goto out_put;
352 devt = MKDEV(BLOCK_EXT_MAJOR, err);
353 }
354 pdev->devt = devt;
355
356 if (info) {
357 err = -ENOMEM;
358 bdev->bd_meta_info = kmemdup(info, sizeof(*info), GFP_KERNEL);
359 if (!bdev->bd_meta_info)
360 goto out_put;
361 }
362
363 /* delay uevent until 'holders' subdir is created */
364 dev_set_uevent_suppress(dev: pdev, val: 1);
365 err = device_add(dev: pdev);
366 if (err)
367 goto out_put;
368
369 err = -ENOMEM;
370 bdev->bd_holder_dir = kobject_create_and_add(name: "holders", parent: &pdev->kobj);
371 if (!bdev->bd_holder_dir)
372 goto out_del;
373
374 dev_set_uevent_suppress(dev: pdev, val: 0);
375 if (flags & ADDPART_FLAG_WHOLEDISK) {
376 err = device_create_file(device: pdev, entry: &dev_attr_whole_disk);
377 if (err)
378 goto out_del;
379 }
380
381 if (flags & ADDPART_FLAG_READONLY)
382 bdev_set_flag(bdev, BD_READ_ONLY);
383
384 /* everything is up and running, commence */
385 err = xa_insert(xa: &disk->part_tbl, index: partno, entry: bdev, GFP_KERNEL);
386 if (err)
387 goto out_del;
388 bdev_add(bdev, dev: devt);
389
390 /* suppress uevent if the disk suppresses it */
391 if (!dev_get_uevent_suppress(dev: ddev))
392 kobject_uevent(kobj: &pdev->kobj, action: KOBJ_ADD);
393 return bdev;
394
395out_del:
396 kobject_put(kobj: bdev->bd_holder_dir);
397 device_del(dev: pdev);
398out_put:
399 put_device(dev: pdev);
400 return ERR_PTR(error: err);
401out_put_disk:
402 put_disk(disk);
403 return ERR_PTR(error: err);
404}
405
406static bool partition_overlaps(struct gendisk *disk, sector_t start,
407 sector_t length, int skip_partno)
408{
409 struct block_device *part;
410 bool overlap = false;
411 unsigned long idx;
412
413 rcu_read_lock();
414 xa_for_each_start(&disk->part_tbl, idx, part, 1) {
415 if (bdev_partno(bdev: part) != skip_partno &&
416 start < part->bd_start_sect + bdev_nr_sectors(bdev: part) &&
417 start + length > part->bd_start_sect) {
418 overlap = true;
419 break;
420 }
421 }
422 rcu_read_unlock();
423
424 return overlap;
425}
426
427int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
428 sector_t length)
429{
430 struct block_device *part;
431 int ret;
432
433 mutex_lock(lock: &disk->open_mutex);
434 if (!disk_live(disk)) {
435 ret = -ENXIO;
436 goto out;
437 }
438
439 if (disk->flags & GENHD_FL_NO_PART) {
440 ret = -EINVAL;
441 goto out;
442 }
443
444 if (partition_overlaps(disk, start, length, skip_partno: -1)) {
445 ret = -EBUSY;
446 goto out;
447 }
448
449 part = add_partition(disk, partno, start, len: length,
450 ADDPART_FLAG_NONE, NULL);
451 ret = PTR_ERR_OR_ZERO(ptr: part);
452out:
453 mutex_unlock(lock: &disk->open_mutex);
454 return ret;
455}
456
457int bdev_del_partition(struct gendisk *disk, int partno)
458{
459 struct block_device *part = NULL;
460 int ret = -ENXIO;
461
462 mutex_lock(lock: &disk->open_mutex);
463 part = xa_load(&disk->part_tbl, index: partno);
464 if (!part)
465 goto out_unlock;
466
467 ret = -EBUSY;
468 if (atomic_read(v: &part->bd_openers))
469 goto out_unlock;
470
471 /*
472 * We verified that @part->bd_openers is zero above and so
473 * @part->bd_holder{_ops} can't be set. And since we hold
474 * @disk->open_mutex the device can't be claimed by anyone.
475 *
476 * So no need to call @part->bd_holder_ops->mark_dead() here.
477 * Just delete the partition and invalidate it.
478 */
479
480 bdev_unhash(bdev: part);
481 invalidate_bdev(bdev: part);
482 drop_partition(part);
483 ret = 0;
484out_unlock:
485 mutex_unlock(lock: &disk->open_mutex);
486 return ret;
487}
488
489int bdev_resize_partition(struct gendisk *disk, int partno, sector_t start,
490 sector_t length)
491{
492 struct block_device *part = NULL;
493 int ret = -ENXIO;
494
495 mutex_lock(lock: &disk->open_mutex);
496 part = xa_load(&disk->part_tbl, index: partno);
497 if (!part)
498 goto out_unlock;
499
500 ret = -EINVAL;
501 if (start != part->bd_start_sect)
502 goto out_unlock;
503
504 ret = -EBUSY;
505 if (partition_overlaps(disk, start, length, skip_partno: partno))
506 goto out_unlock;
507
508 bdev_set_nr_sectors(bdev: part, sectors: length);
509
510 ret = 0;
511out_unlock:
512 mutex_unlock(lock: &disk->open_mutex);
513 return ret;
514}
515
516static bool disk_unlock_native_capacity(struct gendisk *disk)
517{
518 if (!disk->fops->unlock_native_capacity ||
519 test_and_set_bit(GD_NATIVE_CAPACITY, addr: &disk->state)) {
520 printk(KERN_CONT "truncated\n");
521 return false;
522 }
523
524 printk(KERN_CONT "enabling native capacity\n");
525 disk->fops->unlock_native_capacity(disk);
526 return true;
527}
528
529static bool blk_add_partition(struct gendisk *disk,
530 struct parsed_partitions *state, int p)
531{
532 sector_t size = state->parts[p].size;
533 sector_t from = state->parts[p].from;
534 struct block_device *part;
535
536 if (!size)
537 return true;
538
539 if (from >= get_capacity(disk)) {
540 printk(KERN_WARNING
541 "%s: p%d start %llu is beyond EOD, ",
542 disk->disk_name, p, (unsigned long long) from);
543 if (disk_unlock_native_capacity(disk))
544 return false;
545 return true;
546 }
547
548 if (from + size > get_capacity(disk)) {
549 printk(KERN_WARNING
550 "%s: p%d size %llu extends beyond EOD, ",
551 disk->disk_name, p, (unsigned long long) size);
552
553 if (disk_unlock_native_capacity(disk))
554 return false;
555
556 /*
557 * We can not ignore partitions of broken tables created by for
558 * example camera firmware, but we limit them to the end of the
559 * disk to avoid creating invalid block devices.
560 */
561 size = get_capacity(disk) - from;
562 }
563
564 part = add_partition(disk, partno: p, start: from, len: size, flags: state->parts[p].flags,
565 info: &state->parts[p].info);
566 if (IS_ERR(ptr: part)) {
567 if (PTR_ERR(ptr: part) != -ENXIO) {
568 printk(KERN_ERR " %s: p%d could not be added: %pe\n",
569 disk->disk_name, p, part);
570 }
571 return true;
572 }
573
574 if (IS_BUILTIN(CONFIG_BLK_DEV_MD) &&
575 (state->parts[p].flags & ADDPART_FLAG_RAID))
576 md_autodetect_dev(dev: part->bd_dev);
577
578 return true;
579}
580
581static int blk_add_partitions(struct gendisk *disk)
582{
583 struct parsed_partitions *state;
584 int ret = -EAGAIN, p;
585
586 if (!disk_has_partscan(disk))
587 return 0;
588
589 state = check_partition(hd: disk);
590 if (!state)
591 return 0;
592 if (IS_ERR(ptr: state)) {
593 /*
594 * I/O error reading the partition table. If we tried to read
595 * beyond EOD, retry after unlocking the native capacity.
596 */
597 if (PTR_ERR(ptr: state) == -ENOSPC) {
598 printk(KERN_WARNING "%s: partition table beyond EOD, ",
599 disk->disk_name);
600 if (disk_unlock_native_capacity(disk))
601 return -EAGAIN;
602 }
603 return -EIO;
604 }
605
606 /*
607 * Partitions are not supported on host managed zoned block devices.
608 */
609 if (bdev_is_zoned(bdev: disk->part0)) {
610 pr_warn("%s: ignoring partition table on host managed zoned block device\n",
611 disk->disk_name);
612 ret = 0;
613 goto out_free_state;
614 }
615
616 /*
617 * If we read beyond EOD, try unlocking native capacity even if the
618 * partition table was successfully read as we could be missing some
619 * partitions.
620 */
621 if (state->access_beyond_eod) {
622 printk(KERN_WARNING
623 "%s: partition table partially beyond EOD, ",
624 disk->disk_name);
625 if (disk_unlock_native_capacity(disk))
626 goto out_free_state;
627 }
628
629 /* tell userspace that the media / partition table may have changed */
630 kobject_uevent(kobj: &disk_to_dev(disk)->kobj, action: KOBJ_CHANGE);
631
632 for (p = 1; p < state->limit; p++)
633 if (!blk_add_partition(disk, state, p))
634 goto out_free_state;
635
636 ret = 0;
637out_free_state:
638 free_partitions(state);
639 return ret;
640}
641
642int bdev_disk_changed(struct gendisk *disk, bool invalidate)
643{
644 struct block_device *part;
645 unsigned long idx;
646 int ret = 0;
647
648 lockdep_assert_held(&disk->open_mutex);
649
650 if (!disk_live(disk))
651 return -ENXIO;
652
653rescan:
654 if (disk->open_partitions)
655 return -EBUSY;
656 sync_blockdev(bdev: disk->part0);
657 invalidate_bdev(bdev: disk->part0);
658
659 xa_for_each_start(&disk->part_tbl, idx, part, 1) {
660 /*
661 * Remove the block device from the inode hash, so that
662 * it cannot be looked up any more even when openers
663 * still hold references.
664 */
665 bdev_unhash(bdev: part);
666
667 /*
668 * If @disk->open_partitions isn't elevated but there's
669 * still an active holder of that block device things
670 * are broken.
671 */
672 WARN_ON_ONCE(atomic_read(&part->bd_openers));
673 invalidate_bdev(bdev: part);
674 drop_partition(part);
675 }
676 clear_bit(GD_NEED_PART_SCAN, addr: &disk->state);
677
678 /*
679 * Historically we only set the capacity to zero for devices that
680 * support partitions (independ of actually having partitions created).
681 * Doing that is rather inconsistent, but changing it broke legacy
682 * udisks polling for legacy ide-cdrom devices. Use the crude check
683 * below to get the sane behavior for most device while not breaking
684 * userspace for this particular setup.
685 */
686 if (invalidate) {
687 if (!(disk->flags & GENHD_FL_NO_PART) ||
688 !(disk->flags & GENHD_FL_REMOVABLE))
689 set_capacity(disk, size: 0);
690 }
691
692 if (get_capacity(disk)) {
693 ret = blk_add_partitions(disk);
694 if (ret == -EAGAIN)
695 goto rescan;
696 } else if (invalidate) {
697 /*
698 * Tell userspace that the media / partition table may have
699 * changed.
700 */
701 kobject_uevent(kobj: &disk_to_dev(disk)->kobj, action: KOBJ_CHANGE);
702 }
703
704 return ret;
705}
706/*
707 * Only exported for loop and dasd for historic reasons. Don't use in new
708 * code!
709 */
710EXPORT_SYMBOL_GPL(bdev_disk_changed);
711
712void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
713{
714 struct address_space *mapping = state->disk->part0->bd_mapping;
715 struct folio *folio;
716
717 if (n >= get_capacity(disk: state->disk)) {
718 state->access_beyond_eod = true;
719 goto out;
720 }
721
722 folio = read_mapping_folio(mapping, index: n >> PAGE_SECTORS_SHIFT, NULL);
723 if (IS_ERR(ptr: folio))
724 goto out;
725
726 p->v = folio;
727 return folio_address(folio) + offset_in_folio(folio, n * SECTOR_SIZE);
728out:
729 p->v = NULL;
730 return NULL;
731}
732