1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 1991-1998 Linus Torvalds
4 * Re-organised Feb 1998 Russell King
5 * Copyright (C) 2020 Christoph Hellwig
8 #include <linux/slab.h>
9 #include <linux/ctype.h>
10 #include <linux/genhd.h>
11 #include <linux/vmalloc.h>
12 #include <linux/blktrace_api.h>
13 #include <linux/raid/detect.h>
16 static int (*check_part[])(struct parsed_partitions *) = {
18 * Probe partition formats with tables at disk address 0
19 * that also have an ADFS boot block at 0xdc0.
21 #ifdef CONFIG_ACORN_PARTITION_ICS
24 #ifdef CONFIG_ACORN_PARTITION_POWERTEC
25 adfspart_check_POWERTEC,
27 #ifdef CONFIG_ACORN_PARTITION_EESOX
32 * Now move on to formats that only have partition info at
33 * disk address 0xdc0. Since these may also have stale
34 * PC/BIOS partition tables, they need to come before
37 #ifdef CONFIG_ACORN_PARTITION_CUMANA
38 adfspart_check_CUMANA,
40 #ifdef CONFIG_ACORN_PARTITION_ADFS
44 #ifdef CONFIG_CMDLINE_PARTITION
47 #ifdef CONFIG_EFI_PARTITION
48 efi_partition, /* this must come before msdos */
50 #ifdef CONFIG_SGI_PARTITION
53 #ifdef CONFIG_LDM_PARTITION
54 ldm_partition, /* this must come before msdos */
56 #ifdef CONFIG_MSDOS_PARTITION
59 #ifdef CONFIG_OSF_PARTITION
62 #ifdef CONFIG_SUN_PARTITION
65 #ifdef CONFIG_AMIGA_PARTITION
68 #ifdef CONFIG_ATARI_PARTITION
71 #ifdef CONFIG_MAC_PARTITION
74 #ifdef CONFIG_ULTRIX_PARTITION
77 #ifdef CONFIG_IBM_PARTITION
80 #ifdef CONFIG_KARMA_PARTITION
83 #ifdef CONFIG_SYSV68_PARTITION
89 static void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors)
91 spin_lock(&bdev->bd_size_lock);
92 i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
93 spin_unlock(&bdev->bd_size_lock);
96 static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
98 struct parsed_partitions *state;
101 state = kzalloc(sizeof(*state), GFP_KERNEL);
105 nr = disk_max_parts(hd);
106 state->parts = vzalloc(array_size(nr, sizeof(state->parts[0])));
117 static void free_partitions(struct parsed_partitions *state)
123 static struct parsed_partitions *check_partition(struct gendisk *hd,
124 struct block_device *bdev)
126 struct parsed_partitions *state;
129 state = allocate_partitions(hd);
132 state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
133 if (!state->pp_buf) {
134 free_partitions(state);
137 state->pp_buf[0] = '\0';
140 disk_name(hd, 0, state->name);
141 snprintf(state->pp_buf, PAGE_SIZE, " %s:", state->name);
142 if (isdigit(state->name[strlen(state->name)-1]))
143 sprintf(state->name, "p");
146 while (!res && check_part[i]) {
147 memset(state->parts, 0, state->limit * sizeof(state->parts[0]));
148 res = check_part[i++](state);
151 * We have hit an I/O error which we don't report now.
152 * But record it, and let the others do their job.
160 printk(KERN_INFO "%s", state->pp_buf);
162 free_page((unsigned long)state->pp_buf);
165 if (state->access_beyond_eod)
168 * The partition is unrecognized. So report I/O errors if there were any
173 strlcat(state->pp_buf,
174 " unable to read partition table\n", PAGE_SIZE);
175 printk(KERN_INFO "%s", state->pp_buf);
178 free_page((unsigned long)state->pp_buf);
179 free_partitions(state);
183 static ssize_t part_partition_show(struct device *dev,
184 struct device_attribute *attr, char *buf)
186 return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_partno);
189 static ssize_t part_start_show(struct device *dev,
190 struct device_attribute *attr, char *buf)
192 return sprintf(buf, "%llu\n", dev_to_bdev(dev)->bd_start_sect);
195 static ssize_t part_ro_show(struct device *dev,
196 struct device_attribute *attr, char *buf)
198 return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_read_only);
201 static ssize_t part_alignment_offset_show(struct device *dev,
202 struct device_attribute *attr, char *buf)
204 struct block_device *bdev = dev_to_bdev(dev);
206 return sprintf(buf, "%u\n",
207 queue_limit_alignment_offset(&bdev->bd_disk->queue->limits,
208 bdev->bd_start_sect));
211 static ssize_t part_discard_alignment_show(struct device *dev,
212 struct device_attribute *attr, char *buf)
214 struct block_device *bdev = dev_to_bdev(dev);
216 return sprintf(buf, "%u\n",
217 queue_limit_discard_alignment(&bdev->bd_disk->queue->limits,
218 bdev->bd_start_sect));
221 static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
222 static DEVICE_ATTR(start, 0444, part_start_show, NULL);
223 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
224 static DEVICE_ATTR(ro, 0444, part_ro_show, NULL);
225 static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL);
226 static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL);
227 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
228 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
229 #ifdef CONFIG_FAIL_MAKE_REQUEST
230 static struct device_attribute dev_attr_fail =
231 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
234 static struct attribute *part_attrs[] = {
235 &dev_attr_partition.attr,
236 &dev_attr_start.attr,
239 &dev_attr_alignment_offset.attr,
240 &dev_attr_discard_alignment.attr,
242 &dev_attr_inflight.attr,
243 #ifdef CONFIG_FAIL_MAKE_REQUEST
249 static struct attribute_group part_attr_group = {
253 static const struct attribute_group *part_attr_groups[] = {
255 #ifdef CONFIG_BLK_DEV_IO_TRACE
256 &blk_trace_attr_group,
261 static void part_release(struct device *dev)
263 blk_free_devt(dev->devt);
264 bdput(dev_to_bdev(dev));
267 static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
269 struct block_device *part = dev_to_bdev(dev);
271 add_uevent_var(env, "PARTN=%u", part->bd_partno);
272 if (part->bd_meta_info && part->bd_meta_info->volname[0])
273 add_uevent_var(env, "PARTNAME=%s", part->bd_meta_info->volname);
277 struct device_type part_type = {
279 .groups = part_attr_groups,
280 .release = part_release,
281 .uevent = part_uevent,
285 * Must be called either with bd_mutex held, before a disk can be opened or
286 * after all disk users are gone.
288 void delete_partition(struct block_device *part)
290 struct gendisk *disk = part->bd_disk;
291 struct disk_part_tbl *ptbl =
292 rcu_dereference_protected(disk->part_tbl, 1);
294 rcu_assign_pointer(ptbl->part[part->bd_partno], NULL);
295 rcu_assign_pointer(ptbl->last_lookup, NULL);
297 kobject_put(part->bd_holder_dir);
298 device_del(&part->bd_device);
301 * Remove the block device from the inode hash, so that it cannot be
302 * looked up any more even when openers still hold references.
304 remove_inode_hash(part->bd_inode);
306 put_device(&part->bd_device);
309 static ssize_t whole_disk_show(struct device *dev,
310 struct device_attribute *attr, char *buf)
314 static DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
317 * Must be called either with bd_mutex held, before a disk can be opened or
318 * after all disk users are gone.
320 static struct block_device *add_partition(struct gendisk *disk, int partno,
321 sector_t start, sector_t len, int flags,
322 struct partition_meta_info *info)
324 dev_t devt = MKDEV(0, 0);
325 struct device *ddev = disk_to_dev(disk);
327 struct block_device *bdev;
328 struct disk_part_tbl *ptbl;
333 * Partitions are not supported on zoned block devices that are used as
336 switch (disk->queue->limits.zoned) {
338 pr_warn("%s: partitions not supported on host managed zoned block device\n",
340 return ERR_PTR(-ENXIO);
342 pr_info("%s: disabling host aware zoned block device support due to partitions\n",
344 disk->queue->limits.zoned = BLK_ZONED_NONE;
350 err = disk_expand_part_tbl(disk, partno);
353 ptbl = rcu_dereference_protected(disk->part_tbl, 1);
355 if (ptbl->part[partno])
356 return ERR_PTR(-EBUSY);
358 bdev = bdev_alloc(disk, partno);
360 return ERR_PTR(-ENOMEM);
362 bdev->bd_start_sect = start;
363 bdev_set_nr_sectors(bdev, len);
364 bdev->bd_read_only = get_disk_ro(disk);
368 bdev->bd_meta_info = kmemdup(info, sizeof(*info), GFP_KERNEL);
369 if (!bdev->bd_meta_info)
373 pdev = &bdev->bd_device;
374 dname = dev_name(ddev);
375 if (isdigit(dname[strlen(dname) - 1]))
376 dev_set_name(pdev, "%sp%d", dname, partno);
378 dev_set_name(pdev, "%s%d", dname, partno);
380 device_initialize(pdev);
381 pdev->class = &block_class;
382 pdev->type = &part_type;
385 err = blk_alloc_devt(bdev, &devt);
390 /* delay uevent until 'holders' subdir is created */
391 dev_set_uevent_suppress(pdev, 1);
392 err = device_add(pdev);
397 bdev->bd_holder_dir = kobject_create_and_add("holders", &pdev->kobj);
398 if (!bdev->bd_holder_dir)
401 dev_set_uevent_suppress(pdev, 0);
402 if (flags & ADDPART_FLAG_WHOLEDISK) {
403 err = device_create_file(pdev, &dev_attr_whole_disk);
408 /* everything is up and running, commence */
409 bdev_add(bdev, devt);
410 rcu_assign_pointer(ptbl->part[partno], bdev);
412 /* suppress uevent if the disk suppresses it */
413 if (!dev_get_uevent_suppress(ddev))
414 kobject_uevent(&pdev->kobj, KOBJ_ADD);
421 kobject_put(bdev->bd_holder_dir);
428 static bool partition_overlaps(struct gendisk *disk, sector_t start,
429 sector_t length, int skip_partno)
431 struct disk_part_iter piter;
432 struct block_device *part;
433 bool overlap = false;
435 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
436 while ((part = disk_part_iter_next(&piter))) {
437 if (part->bd_partno == skip_partno ||
438 start >= part->bd_start_sect + bdev_nr_sectors(part) ||
439 start + length <= part->bd_start_sect)
445 disk_part_iter_exit(&piter);
449 int bdev_add_partition(struct block_device *bdev, int partno,
450 sector_t start, sector_t length)
452 struct block_device *part;
454 mutex_lock(&bdev->bd_mutex);
455 if (partition_overlaps(bdev->bd_disk, start, length, -1)) {
456 mutex_unlock(&bdev->bd_mutex);
460 part = add_partition(bdev->bd_disk, partno, start, length,
461 ADDPART_FLAG_NONE, NULL);
462 mutex_unlock(&bdev->bd_mutex);
463 return PTR_ERR_OR_ZERO(part);
466 int bdev_del_partition(struct block_device *bdev, int partno)
468 struct block_device *part;
471 part = bdget_disk(bdev->bd_disk, partno);
475 mutex_lock(&part->bd_mutex);
476 mutex_lock_nested(&bdev->bd_mutex, 1);
479 if (part->bd_openers)
483 invalidate_bdev(part);
485 delete_partition(part);
488 mutex_unlock(&bdev->bd_mutex);
489 mutex_unlock(&part->bd_mutex);
494 int bdev_resize_partition(struct block_device *bdev, int partno,
495 sector_t start, sector_t length)
497 struct block_device *part;
500 part = bdget_disk(bdev->bd_disk, partno);
504 mutex_lock(&part->bd_mutex);
505 mutex_lock_nested(&bdev->bd_mutex, 1);
507 if (start != part->bd_start_sect)
511 if (partition_overlaps(bdev->bd_disk, start, length, partno))
514 bdev_set_nr_sectors(part, length);
518 mutex_unlock(&part->bd_mutex);
519 mutex_unlock(&bdev->bd_mutex);
524 static bool disk_unlock_native_capacity(struct gendisk *disk)
526 const struct block_device_operations *bdops = disk->fops;
528 if (bdops->unlock_native_capacity &&
529 !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
530 printk(KERN_CONT "enabling native capacity\n");
531 bdops->unlock_native_capacity(disk);
532 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
535 printk(KERN_CONT "truncated\n");
540 int blk_drop_partitions(struct block_device *bdev)
542 struct disk_part_iter piter;
543 struct block_device *part;
545 if (bdev->bd_part_count)
549 invalidate_bdev(bdev);
551 disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY);
552 while ((part = disk_part_iter_next(&piter)))
553 delete_partition(part);
554 disk_part_iter_exit(&piter);
559 /* for historic reasons in the DASD driver */
560 EXPORT_SYMBOL_GPL(blk_drop_partitions);
563 static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
564 struct parsed_partitions *state, int p)
566 sector_t size = state->parts[p].size;
567 sector_t from = state->parts[p].from;
568 struct block_device *part;
573 if (from >= get_capacity(disk)) {
575 "%s: p%d start %llu is beyond EOD, ",
576 disk->disk_name, p, (unsigned long long) from);
577 if (disk_unlock_native_capacity(disk))
582 if (from + size > get_capacity(disk)) {
584 "%s: p%d size %llu extends beyond EOD, ",
585 disk->disk_name, p, (unsigned long long) size);
587 if (disk_unlock_native_capacity(disk))
591 * We can not ignore partitions of broken tables created by for
592 * example camera firmware, but we limit them to the end of the
593 * disk to avoid creating invalid block devices.
595 size = get_capacity(disk) - from;
598 part = add_partition(disk, p, from, size, state->parts[p].flags,
599 &state->parts[p].info);
600 if (IS_ERR(part) && PTR_ERR(part) != -ENXIO) {
601 printk(KERN_ERR " %s: p%d could not be added: %ld\n",
602 disk->disk_name, p, -PTR_ERR(part));
606 if (IS_BUILTIN(CONFIG_BLK_DEV_MD) &&
607 (state->parts[p].flags & ADDPART_FLAG_RAID))
608 md_autodetect_dev(part->bd_dev);
613 int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
615 struct parsed_partitions *state;
616 int ret = -EAGAIN, p, highest;
618 if (!disk_part_scan_enabled(disk))
621 state = check_partition(disk, bdev);
626 * I/O error reading the partition table. If we tried to read
627 * beyond EOD, retry after unlocking the native capacity.
629 if (PTR_ERR(state) == -ENOSPC) {
630 printk(KERN_WARNING "%s: partition table beyond EOD, ",
632 if (disk_unlock_native_capacity(disk))
639 * Partitions are not supported on host managed zoned block devices.
641 if (disk->queue->limits.zoned == BLK_ZONED_HM) {
642 pr_warn("%s: ignoring partition table on host managed zoned block device\n",
649 * If we read beyond EOD, try unlocking native capacity even if the
650 * partition table was successfully read as we could be missing some
653 if (state->access_beyond_eod) {
655 "%s: partition table partially beyond EOD, ",
657 if (disk_unlock_native_capacity(disk))
661 /* tell userspace that the media / partition table may have changed */
662 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
665 * Detect the highest partition number and preallocate disk->part_tbl.
666 * This is an optimization and not strictly necessary.
668 for (p = 1, highest = 0; p < state->limit; p++)
669 if (state->parts[p].size)
671 disk_expand_part_tbl(disk, highest);
673 for (p = 1; p < state->limit; p++)
674 if (!blk_add_partition(disk, bdev, state, p))
679 free_partitions(state);
683 void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
685 struct address_space *mapping = state->bdev->bd_inode->i_mapping;
688 if (n >= get_capacity(state->bdev->bd_disk)) {
689 state->access_beyond_eod = true;
693 page = read_mapping_page(mapping,
694 (pgoff_t)(n >> (PAGE_SHIFT - 9)), NULL);
701 return (unsigned char *)page_address(page) +
702 ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << SECTOR_SHIFT);