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);
203 return sprintf(buf, "%u\n",
204 queue_limit_alignment_offset(&part_to_disk(p)->queue->limits,
208 static ssize_t part_discard_alignment_show(struct device *dev,
209 struct device_attribute *attr, char *buf)
211 struct hd_struct *p = dev_to_part(dev);
213 return sprintf(buf, "%u\n",
214 queue_limit_discard_alignment(&part_to_disk(p)->queue->limits,
218 static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
219 static DEVICE_ATTR(start, 0444, part_start_show, NULL);
220 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
221 static DEVICE_ATTR(ro, 0444, part_ro_show, NULL);
222 static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL);
223 static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL);
224 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
225 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
226 #ifdef CONFIG_FAIL_MAKE_REQUEST
227 static struct device_attribute dev_attr_fail =
228 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
231 static struct attribute *part_attrs[] = {
232 &dev_attr_partition.attr,
233 &dev_attr_start.attr,
236 &dev_attr_alignment_offset.attr,
237 &dev_attr_discard_alignment.attr,
239 &dev_attr_inflight.attr,
240 #ifdef CONFIG_FAIL_MAKE_REQUEST
246 static struct attribute_group part_attr_group = {
250 static const struct attribute_group *part_attr_groups[] = {
252 #ifdef CONFIG_BLK_DEV_IO_TRACE
253 &blk_trace_attr_group,
258 static void part_release(struct device *dev)
260 struct hd_struct *p = dev_to_part(dev);
261 blk_free_devt(dev->devt);
266 static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
268 struct hd_struct *part = dev_to_part(dev);
270 add_uevent_var(env, "PARTN=%u", part->partno);
271 if (part->info && part->info->volname[0])
272 add_uevent_var(env, "PARTNAME=%s", part->info->volname);
276 struct device_type part_type = {
278 .groups = part_attr_groups,
279 .release = part_release,
280 .uevent = part_uevent,
283 static void hd_struct_free_work(struct work_struct *work)
285 struct hd_struct *part =
286 container_of(to_rcu_work(work), struct hd_struct, rcu_work);
287 struct gendisk *disk = part_to_disk(part);
290 * Release the disk reference acquired in delete_partition here.
291 * We can't release it in hd_struct_free because the final put_device
292 * needs process context and thus can't be run directly from a
293 * percpu_ref ->release handler.
295 put_device(disk_to_dev(disk));
297 part->start_sect = 0;
299 part_stat_set_all(part, 0);
300 put_device(part_to_dev(part));
303 static void hd_struct_free(struct percpu_ref *ref)
305 struct hd_struct *part = container_of(ref, struct hd_struct, ref);
306 struct gendisk *disk = part_to_disk(part);
307 struct disk_part_tbl *ptbl =
308 rcu_dereference_protected(disk->part_tbl, 1);
310 rcu_assign_pointer(ptbl->last_lookup, NULL);
312 INIT_RCU_WORK(&part->rcu_work, hd_struct_free_work);
313 queue_rcu_work(system_wq, &part->rcu_work);
316 int hd_ref_init(struct hd_struct *part)
318 if (percpu_ref_init(&part->ref, hd_struct_free, 0, GFP_KERNEL))
324 * Must be called either with bd_mutex held, before a disk can be opened or
325 * after all disk users are gone.
327 void delete_partition(struct hd_struct *part)
329 struct gendisk *disk = part_to_disk(part);
330 struct disk_part_tbl *ptbl =
331 rcu_dereference_protected(disk->part_tbl, 1);
334 * ->part_tbl is referenced in this part's release handler, so
335 * we have to hold the disk device
337 get_device(disk_to_dev(disk));
338 rcu_assign_pointer(ptbl->part[part->partno], NULL);
339 kobject_put(part->holder_dir);
340 device_del(part_to_dev(part));
343 * Remove gendisk pointer from idr so that it cannot be looked up
344 * while RCU period before freeing gendisk is running to prevent
345 * use-after-free issues. Note that the device number stays
346 * "in-use" until we really free the gendisk.
348 blk_invalidate_devt(part_devt(part));
349 percpu_ref_kill(&part->ref);
352 static ssize_t whole_disk_show(struct device *dev,
353 struct device_attribute *attr, char *buf)
357 static DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
360 * Must be called either with bd_mutex held, before a disk can be opened or
361 * after all disk users are gone.
363 static struct hd_struct *add_partition(struct gendisk *disk, int partno,
364 sector_t start, sector_t len, int flags,
365 struct partition_meta_info *info)
368 dev_t devt = MKDEV(0, 0);
369 struct device *ddev = disk_to_dev(disk);
371 struct disk_part_tbl *ptbl;
376 * Partitions are not supported on zoned block devices that are used as
379 switch (disk->queue->limits.zoned) {
381 pr_warn("%s: partitions not supported on host managed zoned block device\n",
383 return ERR_PTR(-ENXIO);
385 pr_info("%s: disabling host aware zoned block device support due to partitions\n",
387 disk->queue->limits.zoned = BLK_ZONED_NONE;
393 err = disk_expand_part_tbl(disk, partno);
396 ptbl = rcu_dereference_protected(disk->part_tbl, 1);
398 if (ptbl->part[partno])
399 return ERR_PTR(-EBUSY);
401 p = kzalloc(sizeof(*p), GFP_KERNEL);
403 return ERR_PTR(-EBUSY);
405 p->dkstats = alloc_percpu(struct disk_stats);
411 hd_sects_seq_init(p);
412 pdev = part_to_dev(p);
414 p->start_sect = start;
417 p->policy = get_disk_ro(disk);
420 struct partition_meta_info *pinfo;
422 pinfo = kzalloc_node(sizeof(*pinfo), GFP_KERNEL, disk->node_id);
427 memcpy(pinfo, info, sizeof(*info));
431 dname = dev_name(ddev);
432 if (isdigit(dname[strlen(dname) - 1]))
433 dev_set_name(pdev, "%sp%d", dname, partno);
435 dev_set_name(pdev, "%s%d", dname, partno);
437 device_initialize(pdev);
438 pdev->class = &block_class;
439 pdev->type = &part_type;
442 err = blk_alloc_devt(p, &devt);
447 /* delay uevent until 'holders' subdir is created */
448 dev_set_uevent_suppress(pdev, 1);
449 err = device_add(pdev);
454 p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
458 dev_set_uevent_suppress(pdev, 0);
459 if (flags & ADDPART_FLAG_WHOLEDISK) {
460 err = device_create_file(pdev, &dev_attr_whole_disk);
465 err = hd_ref_init(p);
467 if (flags & ADDPART_FLAG_WHOLEDISK)
468 goto out_remove_file;
472 /* everything is up and running, commence */
473 rcu_assign_pointer(ptbl->part[partno], p);
475 /* suppress uevent if the disk suppresses it */
476 if (!dev_get_uevent_suppress(ddev))
477 kobject_uevent(&pdev->kobj, KOBJ_ADD);
483 free_percpu(p->dkstats);
488 device_remove_file(pdev, &dev_attr_whole_disk);
490 kobject_put(p->holder_dir);
497 static bool partition_overlaps(struct gendisk *disk, sector_t start,
498 sector_t length, int skip_partno)
500 struct disk_part_iter piter;
501 struct hd_struct *part;
502 bool overlap = false;
504 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
505 while ((part = disk_part_iter_next(&piter))) {
506 if (part->partno == skip_partno ||
507 start >= part->start_sect + part->nr_sects ||
508 start + length <= part->start_sect)
514 disk_part_iter_exit(&piter);
518 int bdev_add_partition(struct block_device *bdev, int partno,
519 sector_t start, sector_t length)
521 struct hd_struct *part;
523 mutex_lock(&bdev->bd_mutex);
524 if (partition_overlaps(bdev->bd_disk, start, length, -1)) {
525 mutex_unlock(&bdev->bd_mutex);
529 part = add_partition(bdev->bd_disk, partno, start, length,
530 ADDPART_FLAG_NONE, NULL);
531 mutex_unlock(&bdev->bd_mutex);
532 return PTR_ERR_OR_ZERO(part);
535 int bdev_del_partition(struct block_device *bdev, int partno)
537 struct block_device *bdevp;
538 struct hd_struct *part = NULL;
541 bdevp = bdget_disk(bdev->bd_disk, partno);
545 mutex_lock(&bdevp->bd_mutex);
546 mutex_lock_nested(&bdev->bd_mutex, 1);
549 part = disk_get_part(bdev->bd_disk, partno);
554 if (bdevp->bd_openers)
557 sync_blockdev(bdevp);
558 invalidate_bdev(bdevp);
560 delete_partition(part);
563 mutex_unlock(&bdev->bd_mutex);
564 mutex_unlock(&bdevp->bd_mutex);
571 int bdev_resize_partition(struct block_device *bdev, int partno,
572 sector_t start, sector_t length)
574 struct block_device *bdevp;
575 struct hd_struct *part;
578 part = disk_get_part(bdev->bd_disk, partno);
583 bdevp = bdget_part(part);
587 mutex_lock(&bdevp->bd_mutex);
588 mutex_lock_nested(&bdev->bd_mutex, 1);
591 if (start != part->start_sect)
595 if (partition_overlaps(bdev->bd_disk, start, length, partno))
598 part_nr_sects_write(part, length);
599 bd_set_nr_sectors(bdevp, length);
603 mutex_unlock(&bdevp->bd_mutex);
604 mutex_unlock(&bdev->bd_mutex);
611 static bool disk_unlock_native_capacity(struct gendisk *disk)
613 const struct block_device_operations *bdops = disk->fops;
615 if (bdops->unlock_native_capacity &&
616 !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
617 printk(KERN_CONT "enabling native capacity\n");
618 bdops->unlock_native_capacity(disk);
619 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
622 printk(KERN_CONT "truncated\n");
627 int blk_drop_partitions(struct block_device *bdev)
629 struct disk_part_iter piter;
630 struct hd_struct *part;
632 if (bdev->bd_part_count)
636 invalidate_bdev(bdev);
638 disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY);
639 while ((part = disk_part_iter_next(&piter)))
640 delete_partition(part);
641 disk_part_iter_exit(&piter);
646 /* for historic reasons in the DASD driver */
647 EXPORT_SYMBOL_GPL(blk_drop_partitions);
650 static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
651 struct parsed_partitions *state, int p)
653 sector_t size = state->parts[p].size;
654 sector_t from = state->parts[p].from;
655 struct hd_struct *part;
660 if (from >= get_capacity(disk)) {
662 "%s: p%d start %llu is beyond EOD, ",
663 disk->disk_name, p, (unsigned long long) from);
664 if (disk_unlock_native_capacity(disk))
669 if (from + size > get_capacity(disk)) {
671 "%s: p%d size %llu extends beyond EOD, ",
672 disk->disk_name, p, (unsigned long long) size);
674 if (disk_unlock_native_capacity(disk))
678 * We can not ignore partitions of broken tables created by for
679 * example camera firmware, but we limit them to the end of the
680 * disk to avoid creating invalid block devices.
682 size = get_capacity(disk) - from;
685 part = add_partition(disk, p, from, size, state->parts[p].flags,
686 &state->parts[p].info);
687 if (IS_ERR(part) && PTR_ERR(part) != -ENXIO) {
688 printk(KERN_ERR " %s: p%d could not be added: %ld\n",
689 disk->disk_name, p, -PTR_ERR(part));
693 if (IS_BUILTIN(CONFIG_BLK_DEV_MD) &&
694 (state->parts[p].flags & ADDPART_FLAG_RAID))
695 md_autodetect_dev(part_to_dev(part)->devt);
700 int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
702 struct parsed_partitions *state;
703 int ret = -EAGAIN, p, highest;
705 if (!disk_part_scan_enabled(disk))
708 state = check_partition(disk, bdev);
713 * I/O error reading the partition table. If we tried to read
714 * beyond EOD, retry after unlocking the native capacity.
716 if (PTR_ERR(state) == -ENOSPC) {
717 printk(KERN_WARNING "%s: partition table beyond EOD, ",
719 if (disk_unlock_native_capacity(disk))
726 * Partitions are not supported on host managed zoned block devices.
728 if (disk->queue->limits.zoned == BLK_ZONED_HM) {
729 pr_warn("%s: ignoring partition table on host managed zoned block device\n",
736 * If we read beyond EOD, try unlocking native capacity even if the
737 * partition table was successfully read as we could be missing some
740 if (state->access_beyond_eod) {
742 "%s: partition table partially beyond EOD, ",
744 if (disk_unlock_native_capacity(disk))
748 /* tell userspace that the media / partition table may have changed */
749 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
752 * Detect the highest partition number and preallocate disk->part_tbl.
753 * This is an optimization and not strictly necessary.
755 for (p = 1, highest = 0; p < state->limit; p++)
756 if (state->parts[p].size)
758 disk_expand_part_tbl(disk, highest);
760 for (p = 1; p < state->limit; p++)
761 if (!blk_add_partition(disk, bdev, state, p))
766 free_partitions(state);
770 void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
772 struct address_space *mapping = state->bdev->bd_inode->i_mapping;
775 if (n >= get_capacity(state->bdev->bd_disk)) {
776 state->access_beyond_eod = true;
780 page = read_mapping_page(mapping,
781 (pgoff_t)(n >> (PAGE_SHIFT - 9)), NULL);
788 return (unsigned char *)page_address(page) +
789 ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << SECTOR_SHIFT);