724 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 1991-1998 Linus Torvalds4 * Re-organised Feb 1998 Russell King5 * Copyright (C) 2020 Christoph Hellwig6 */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 018 * that also have an ADFS boot block at 0xdc0.19 */20#ifdef CONFIG_ACORN_PARTITION_ICS21 adfspart_check_ICS,22#endif23#ifdef CONFIG_ACORN_PARTITION_POWERTEC24 adfspart_check_POWERTEC,25#endif26#ifdef CONFIG_ACORN_PARTITION_EESOX27 adfspart_check_EESOX,28#endif29 30 /*31 * Now move on to formats that only have partition info at32 * disk address 0xdc0. Since these may also have stale33 * PC/BIOS partition tables, they need to come before34 * the msdos entry.35 */36#ifdef CONFIG_ACORN_PARTITION_CUMANA37 adfspart_check_CUMANA,38#endif39#ifdef CONFIG_ACORN_PARTITION_ADFS40 adfspart_check_ADFS,41#endif42 43#ifdef CONFIG_CMDLINE_PARTITION44 cmdline_partition,45#endif46#ifdef CONFIG_EFI_PARTITION47 efi_partition, /* this must come before msdos */48#endif49#ifdef CONFIG_SGI_PARTITION50 sgi_partition,51#endif52#ifdef CONFIG_LDM_PARTITION53 ldm_partition, /* this must come before msdos */54#endif55#ifdef CONFIG_MSDOS_PARTITION56 msdos_partition,57#endif58#ifdef CONFIG_OSF_PARTITION59 osf_partition,60#endif61#ifdef CONFIG_SUN_PARTITION62 sun_partition,63#endif64#ifdef CONFIG_AMIGA_PARTITION65 amiga_partition,66#endif67#ifdef CONFIG_ATARI_PARTITION68 atari_partition,69#endif70#ifdef CONFIG_MAC_PARTITION71 mac_partition,72#endif73#ifdef CONFIG_ULTRIX_PARTITION74 ultrix_partition,75#endif76#ifdef CONFIG_IBM_PARTITION77 ibm_partition,78#endif79#ifdef CONFIG_KARMA_PARTITION80 karma_partition,81#endif82#ifdef CONFIG_SYSV68_PARTITION83 sysv68_partition,84#endif85 NULL86};87 88static 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 108static void free_partitions(struct parsed_partitions *state)109{110 vfree(state->parts);111 kfree(state);112}113 114static 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 any159 */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 173static 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 179static 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 185static 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 191static 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 197static 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 203static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);204static DEVICE_ATTR(start, 0444, part_start_show, NULL);205static DEVICE_ATTR(size, 0444, part_size_show, NULL);206static DEVICE_ATTR(ro, 0444, part_ro_show, NULL);207static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL);208static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL);209static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);210static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);211#ifdef CONFIG_FAIL_MAKE_REQUEST212static struct device_attribute dev_attr_fail =213 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);214#endif215 216static 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_REQUEST226 &dev_attr_fail.attr,227#endif228 NULL229};230 231static const struct attribute_group part_attr_group = {232 .attrs = part_attrs,233};234 235static const struct attribute_group *part_attr_groups[] = {236 &part_attr_group,237#ifdef CONFIG_BLK_DEV_IO_TRACE238 &blk_trace_attr_group,239#endif240 NULL241};242 243static 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 249static 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 259const struct device_type part_type = {260 .name = "partition",261 .groups = part_attr_groups,262 .release = part_release,263 .uevent = part_uevent,264};265 266void 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 277static ssize_t whole_disk_show(struct device *dev,278 struct device_attribute *attr, char *buf)279{280 return 0;281}282static 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 or286 * after all disk users are gone.287 */288static 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 as306 * 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 else333 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 387out_del:388 kobject_put(bdev->bd_holder_dir);389 device_del(pdev);390out_put:391 put_device(pdev);392 return ERR_PTR(err);393out_put_disk:394 put_disk(disk);395 return ERR_PTR(err);396}397 398static 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 419int 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);444out:445 mutex_unlock(&disk->open_mutex);446 return ret;447}448 449int 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 so465 * @part->bd_holder{_ops} can't be set. And since we hold466 * @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;476out_unlock:477 mutex_unlock(&disk->open_mutex);478 return ret;479}480 481int 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;503out_unlock:504 mutex_unlock(&disk->open_mutex);505 return ret;506}507 508static 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 521static 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_WARNING533 "%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_WARNING542 "%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 for550 * example camera firmware, but we limit them to the end of the551 * 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 573static 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 read587 * 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 the610 * partition table was successfully read as we could be missing some611 * partitions.612 */613 if (state->access_beyond_eod) {614 printk(KERN_WARNING615 "%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;629out_free_state:630 free_partitions(state);631 return ret;632}633 634int 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 645rescan: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 that654 * it cannot be looked up any more even when openers655 * still hold references.656 */657 bdev_unhash(part);658 659 /*660 * If @disk->open_partitions isn't elevated but there's661 * still an active holder of that block device things662 * 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 that672 * support partitions (independ of actually having partitions created).673 * Doing that is rather inconsistent, but changing it broke legacy674 * udisks polling for legacy ide-cdrom devices. Use the crude check675 * below to get the sane behavior for most device while not breaking676 * 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 have691 * 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 new700 * code!701 */702EXPORT_SYMBOL_GPL(bdev_disk_changed);703 704void *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);720out:721 p->v = NULL;722 return NULL;723}724