1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 1991-1998 Linus Torvalds
4 * Re-organised Feb 1998 Russell King
7 #include <linux/slab.h>
8 #include <linux/ctype.h>
9 #include <linux/genhd.h>
10 #include <linux/vmalloc.h>
11 #include <linux/blktrace_api.h>
12 #include <linux/raid/detect.h>
15 static int (*check_part[])(struct parsed_partitions *) = {
17 * Probe partition formats with tables at disk address 0
18 * that also have an ADFS boot block at 0xdc0.
20 #ifdef CONFIG_ACORN_PARTITION_ICS
23 #ifdef CONFIG_ACORN_PARTITION_POWERTEC
24 adfspart_check_POWERTEC,
26 #ifdef CONFIG_ACORN_PARTITION_EESOX
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
36 #ifdef CONFIG_ACORN_PARTITION_CUMANA
37 adfspart_check_CUMANA,
39 #ifdef CONFIG_ACORN_PARTITION_ADFS
43 #ifdef CONFIG_CMDLINE_PARTITION
46 #ifdef CONFIG_EFI_PARTITION
47 efi_partition, /* this must come before msdos */
49 #ifdef CONFIG_SGI_PARTITION
52 #ifdef CONFIG_LDM_PARTITION
53 ldm_partition, /* this must come before msdos */
55 #ifdef CONFIG_MSDOS_PARTITION
58 #ifdef CONFIG_OSF_PARTITION
61 #ifdef CONFIG_SUN_PARTITION
64 #ifdef CONFIG_AMIGA_PARTITION
67 #ifdef CONFIG_ATARI_PARTITION
70 #ifdef CONFIG_MAC_PARTITION
73 #ifdef CONFIG_ULTRIX_PARTITION
76 #ifdef CONFIG_IBM_PARTITION
79 #ifdef CONFIG_KARMA_PARTITION
82 #ifdef CONFIG_SYSV68_PARTITION
88 static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
90 struct parsed_partitions *state;
93 state = kzalloc(sizeof(*state), GFP_KERNEL);
97 nr = disk_max_parts(hd);
98 state->parts = vzalloc(array_size(nr, sizeof(state->parts[0])));
109 static void free_partitions(struct parsed_partitions *state)
115 static struct parsed_partitions *check_partition(struct gendisk *hd,
116 struct block_device *bdev)
118 struct parsed_partitions *state;
121 state = allocate_partitions(hd);
124 state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
125 if (!state->pp_buf) {
126 free_partitions(state);
129 state->pp_buf[0] = '\0';
132 disk_name(hd, 0, state->name);
133 snprintf(state->pp_buf, PAGE_SIZE, " %s:", state->name);
134 if (isdigit(state->name[strlen(state->name)-1]))
135 sprintf(state->name, "p");
138 while (!res && check_part[i]) {
139 memset(state->parts, 0, state->limit * sizeof(state->parts[0]));
140 res = check_part[i++](state);
143 * We have hit an I/O error which we don't report now.
144 * But record it, and let the others do their job.
152 printk(KERN_INFO "%s", state->pp_buf);
154 free_page((unsigned long)state->pp_buf);
157 if (state->access_beyond_eod)
160 * The partition is unrecognized. So report I/O errors if there were any
165 strlcat(state->pp_buf,
166 " unable to read partition table\n", PAGE_SIZE);
167 printk(KERN_INFO "%s", state->pp_buf);
170 free_page((unsigned long)state->pp_buf);
171 free_partitions(state);
175 static ssize_t part_partition_show(struct device *dev,
176 struct device_attribute *attr, char *buf)
178 struct hd_struct *p = dev_to_part(dev);
180 return sprintf(buf, "%d\n", p->partno);
183 static ssize_t part_start_show(struct device *dev,
184 struct device_attribute *attr, char *buf)
186 struct hd_struct *p = dev_to_part(dev);
188 return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
191 static ssize_t part_ro_show(struct device *dev,
192 struct device_attribute *attr, char *buf)
194 struct hd_struct *p = dev_to_part(dev);
195 return sprintf(buf, "%d\n", p->policy ? 1 : 0);
198 static ssize_t part_alignment_offset_show(struct device *dev,
199 struct device_attribute *attr, char *buf)
201 struct hd_struct *p = dev_to_part(dev);
202 return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
205 static ssize_t part_discard_alignment_show(struct device *dev,
206 struct device_attribute *attr, char *buf)
208 struct hd_struct *p = dev_to_part(dev);
209 return sprintf(buf, "%u\n", p->discard_alignment);
212 static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
213 static DEVICE_ATTR(start, 0444, part_start_show, NULL);
214 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
215 static DEVICE_ATTR(ro, 0444, part_ro_show, NULL);
216 static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL);
217 static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL);
218 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
219 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
220 #ifdef CONFIG_FAIL_MAKE_REQUEST
221 static struct device_attribute dev_attr_fail =
222 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
225 static struct attribute *part_attrs[] = {
226 &dev_attr_partition.attr,
227 &dev_attr_start.attr,
230 &dev_attr_alignment_offset.attr,
231 &dev_attr_discard_alignment.attr,
233 &dev_attr_inflight.attr,
234 #ifdef CONFIG_FAIL_MAKE_REQUEST
240 static struct attribute_group part_attr_group = {
244 static const struct attribute_group *part_attr_groups[] = {
246 #ifdef CONFIG_BLK_DEV_IO_TRACE
247 &blk_trace_attr_group,
252 static void part_release(struct device *dev)
254 struct hd_struct *p = dev_to_part(dev);
255 blk_free_devt(dev->devt);
260 static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
262 struct hd_struct *part = dev_to_part(dev);
264 add_uevent_var(env, "PARTN=%u", part->partno);
265 if (part->info && part->info->volname[0])
266 add_uevent_var(env, "PARTNAME=%s", part->info->volname);
270 struct device_type part_type = {
272 .groups = part_attr_groups,
273 .release = part_release,
274 .uevent = part_uevent,
277 static void hd_struct_free_work(struct work_struct *work)
279 struct hd_struct *part =
280 container_of(to_rcu_work(work), struct hd_struct, rcu_work);
281 struct gendisk *disk = part_to_disk(part);
284 * Release the disk reference acquired in delete_partition here.
285 * We can't release it in hd_struct_free because the final put_device
286 * needs process context and thus can't be run directly from a
287 * percpu_ref ->release handler.
289 put_device(disk_to_dev(disk));
291 part->start_sect = 0;
293 part_stat_set_all(part, 0);
294 put_device(part_to_dev(part));
297 static void hd_struct_free(struct percpu_ref *ref)
299 struct hd_struct *part = container_of(ref, struct hd_struct, ref);
300 struct gendisk *disk = part_to_disk(part);
301 struct disk_part_tbl *ptbl =
302 rcu_dereference_protected(disk->part_tbl, 1);
304 rcu_assign_pointer(ptbl->last_lookup, NULL);
306 INIT_RCU_WORK(&part->rcu_work, hd_struct_free_work);
307 queue_rcu_work(system_wq, &part->rcu_work);
310 int hd_ref_init(struct hd_struct *part)
312 if (percpu_ref_init(&part->ref, hd_struct_free, 0, GFP_KERNEL))
318 * Must be called either with bd_mutex held, before a disk can be opened or
319 * after all disk users are gone.
321 void delete_partition(struct gendisk *disk, struct hd_struct *part)
323 struct disk_part_tbl *ptbl =
324 rcu_dereference_protected(disk->part_tbl, 1);
327 * ->part_tbl is referenced in this part's release handler, so
328 * we have to hold the disk device
330 get_device(disk_to_dev(part_to_disk(part)));
331 rcu_assign_pointer(ptbl->part[part->partno], NULL);
332 kobject_put(part->holder_dir);
333 device_del(part_to_dev(part));
336 * Remove gendisk pointer from idr so that it cannot be looked up
337 * while RCU period before freeing gendisk is running to prevent
338 * use-after-free issues. Note that the device number stays
339 * "in-use" until we really free the gendisk.
341 blk_invalidate_devt(part_devt(part));
342 percpu_ref_kill(&part->ref);
345 static ssize_t whole_disk_show(struct device *dev,
346 struct device_attribute *attr, char *buf)
350 static DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
353 * Must be called either with bd_mutex held, before a disk can be opened or
354 * after all disk users are gone.
356 static struct hd_struct *add_partition(struct gendisk *disk, int partno,
357 sector_t start, sector_t len, int flags,
358 struct partition_meta_info *info)
361 dev_t devt = MKDEV(0, 0);
362 struct device *ddev = disk_to_dev(disk);
364 struct disk_part_tbl *ptbl;
369 * Partitions are not supported on zoned block devices that are used as
372 switch (disk->queue->limits.zoned) {
374 pr_warn("%s: partitions not supported on host managed zoned block device\n",
376 return ERR_PTR(-ENXIO);
378 pr_info("%s: disabling host aware zoned block device support due to partitions\n",
380 disk->queue->limits.zoned = BLK_ZONED_NONE;
386 err = disk_expand_part_tbl(disk, partno);
389 ptbl = rcu_dereference_protected(disk->part_tbl, 1);
391 if (ptbl->part[partno])
392 return ERR_PTR(-EBUSY);
394 p = kzalloc(sizeof(*p), GFP_KERNEL);
396 return ERR_PTR(-EBUSY);
398 p->dkstats = alloc_percpu(struct disk_stats);
404 hd_sects_seq_init(p);
405 pdev = part_to_dev(p);
407 p->start_sect = start;
408 p->alignment_offset =
409 queue_limit_alignment_offset(&disk->queue->limits, start);
410 p->discard_alignment =
411 queue_limit_discard_alignment(&disk->queue->limits, start);
414 p->policy = get_disk_ro(disk);
417 struct partition_meta_info *pinfo;
419 pinfo = kzalloc_node(sizeof(*pinfo), GFP_KERNEL, disk->node_id);
424 memcpy(pinfo, info, sizeof(*info));
428 dname = dev_name(ddev);
429 if (isdigit(dname[strlen(dname) - 1]))
430 dev_set_name(pdev, "%sp%d", dname, partno);
432 dev_set_name(pdev, "%s%d", dname, partno);
434 device_initialize(pdev);
435 pdev->class = &block_class;
436 pdev->type = &part_type;
439 err = blk_alloc_devt(p, &devt);
444 /* delay uevent until 'holders' subdir is created */
445 dev_set_uevent_suppress(pdev, 1);
446 err = device_add(pdev);
451 p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
455 dev_set_uevent_suppress(pdev, 0);
456 if (flags & ADDPART_FLAG_WHOLEDISK) {
457 err = device_create_file(pdev, &dev_attr_whole_disk);
462 err = hd_ref_init(p);
464 if (flags & ADDPART_FLAG_WHOLEDISK)
465 goto out_remove_file;
469 /* everything is up and running, commence */
470 rcu_assign_pointer(ptbl->part[partno], p);
472 /* suppress uevent if the disk suppresses it */
473 if (!dev_get_uevent_suppress(ddev))
474 kobject_uevent(&pdev->kobj, KOBJ_ADD);
480 free_percpu(p->dkstats);
485 device_remove_file(pdev, &dev_attr_whole_disk);
487 kobject_put(p->holder_dir);
494 static bool partition_overlaps(struct gendisk *disk, sector_t start,
495 sector_t length, int skip_partno)
497 struct disk_part_iter piter;
498 struct hd_struct *part;
499 bool overlap = false;
501 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
502 while ((part = disk_part_iter_next(&piter))) {
503 if (part->partno == skip_partno ||
504 start >= part->start_sect + part->nr_sects ||
505 start + length <= part->start_sect)
511 disk_part_iter_exit(&piter);
515 int bdev_add_partition(struct block_device *bdev, int partno,
516 sector_t start, sector_t length)
518 struct hd_struct *part;
520 mutex_lock(&bdev->bd_mutex);
521 if (partition_overlaps(bdev->bd_disk, start, length, -1)) {
522 mutex_unlock(&bdev->bd_mutex);
526 part = add_partition(bdev->bd_disk, partno, start, length,
527 ADDPART_FLAG_NONE, NULL);
528 mutex_unlock(&bdev->bd_mutex);
529 return PTR_ERR_OR_ZERO(part);
532 int bdev_del_partition(struct block_device *bdev, int partno)
534 struct block_device *bdevp;
535 struct hd_struct *part = NULL;
538 bdevp = bdget_disk(bdev->bd_disk, partno);
542 mutex_lock(&bdevp->bd_mutex);
543 mutex_lock_nested(&bdev->bd_mutex, 1);
546 part = disk_get_part(bdev->bd_disk, partno);
551 if (bdevp->bd_openers)
554 sync_blockdev(bdevp);
555 invalidate_bdev(bdevp);
557 delete_partition(bdev->bd_disk, part);
560 mutex_unlock(&bdev->bd_mutex);
561 mutex_unlock(&bdevp->bd_mutex);
568 int bdev_resize_partition(struct block_device *bdev, int partno,
569 sector_t start, sector_t length)
571 struct block_device *bdevp;
572 struct hd_struct *part;
575 part = disk_get_part(bdev->bd_disk, partno);
580 bdevp = bdget(part_devt(part));
584 mutex_lock(&bdevp->bd_mutex);
585 mutex_lock_nested(&bdev->bd_mutex, 1);
588 if (start != part->start_sect)
592 if (partition_overlaps(bdev->bd_disk, start, length, partno))
595 part_nr_sects_write(part, (sector_t)length);
596 i_size_write(bdevp->bd_inode, length << SECTOR_SHIFT);
600 mutex_unlock(&bdevp->bd_mutex);
601 mutex_unlock(&bdev->bd_mutex);
608 static bool disk_unlock_native_capacity(struct gendisk *disk)
610 const struct block_device_operations *bdops = disk->fops;
612 if (bdops->unlock_native_capacity &&
613 !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
614 printk(KERN_CONT "enabling native capacity\n");
615 bdops->unlock_native_capacity(disk);
616 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
619 printk(KERN_CONT "truncated\n");
624 int blk_drop_partitions(struct block_device *bdev)
626 struct disk_part_iter piter;
627 struct hd_struct *part;
629 if (bdev->bd_part_count)
633 invalidate_bdev(bdev);
635 disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY);
636 while ((part = disk_part_iter_next(&piter)))
637 delete_partition(bdev->bd_disk, part);
638 disk_part_iter_exit(&piter);
643 /* for historic reasons in the DASD driver */
644 EXPORT_SYMBOL_GPL(blk_drop_partitions);
647 static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
648 struct parsed_partitions *state, int p)
650 sector_t size = state->parts[p].size;
651 sector_t from = state->parts[p].from;
652 struct hd_struct *part;
657 if (from >= get_capacity(disk)) {
659 "%s: p%d start %llu is beyond EOD, ",
660 disk->disk_name, p, (unsigned long long) from);
661 if (disk_unlock_native_capacity(disk))
666 if (from + size > get_capacity(disk)) {
668 "%s: p%d size %llu extends beyond EOD, ",
669 disk->disk_name, p, (unsigned long long) size);
671 if (disk_unlock_native_capacity(disk))
675 * We can not ignore partitions of broken tables created by for
676 * example camera firmware, but we limit them to the end of the
677 * disk to avoid creating invalid block devices.
679 size = get_capacity(disk) - from;
682 part = add_partition(disk, p, from, size, state->parts[p].flags,
683 &state->parts[p].info);
684 if (IS_ERR(part) && PTR_ERR(part) != -ENXIO) {
685 printk(KERN_ERR " %s: p%d could not be added: %ld\n",
686 disk->disk_name, p, -PTR_ERR(part));
690 if (IS_BUILTIN(CONFIG_BLK_DEV_MD) &&
691 (state->parts[p].flags & ADDPART_FLAG_RAID))
692 md_autodetect_dev(part_to_dev(part)->devt);
697 int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
699 struct parsed_partitions *state;
700 int ret = -EAGAIN, p, highest;
702 if (!disk_part_scan_enabled(disk))
705 state = check_partition(disk, bdev);
710 * I/O error reading the partition table. If we tried to read
711 * beyond EOD, retry after unlocking the native capacity.
713 if (PTR_ERR(state) == -ENOSPC) {
714 printk(KERN_WARNING "%s: partition table beyond EOD, ",
716 if (disk_unlock_native_capacity(disk))
723 * Partitions are not supported on host managed zoned block devices.
725 if (disk->queue->limits.zoned == BLK_ZONED_HM) {
726 pr_warn("%s: ignoring partition table on host managed zoned block device\n",
733 * If we read beyond EOD, try unlocking native capacity even if the
734 * partition table was successfully read as we could be missing some
737 if (state->access_beyond_eod) {
739 "%s: partition table partially beyond EOD, ",
741 if (disk_unlock_native_capacity(disk))
745 /* tell userspace that the media / partition table may have changed */
746 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
749 * Detect the highest partition number and preallocate disk->part_tbl.
750 * This is an optimization and not strictly necessary.
752 for (p = 1, highest = 0; p < state->limit; p++)
753 if (state->parts[p].size)
755 disk_expand_part_tbl(disk, highest);
757 for (p = 1; p < state->limit; p++)
758 if (!blk_add_partition(disk, bdev, state, p))
763 free_partitions(state);
767 void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
769 struct address_space *mapping = state->bdev->bd_inode->i_mapping;
772 if (n >= get_capacity(state->bdev->bd_disk)) {
773 state->access_beyond_eod = true;
777 page = read_mapping_page(mapping,
778 (pgoff_t)(n >> (PAGE_SHIFT - 9)), NULL);
785 return (unsigned char *)page_address(page) +
786 ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << SECTOR_SHIFT);