1 // SPDX-License-Identifier: GPL-2.0
3 * Code extracted from drivers/block/genhd.c
4 * Copyright (C) 1991-1998 Linus Torvalds
5 * Re-organised Feb 1998 Russell King
7 * We now have independent partition support from the
8 * block drivers, which allows all the partition code to
9 * be grouped in one location, and it to be mostly self
13 #include <linux/init.h>
14 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/kmod.h>
18 #include <linux/ctype.h>
19 #include <linux/genhd.h>
20 #include <linux/blktrace_api.h>
22 #include "partitions/check.h"
24 #ifdef CONFIG_BLK_DEV_MD
25 extern void md_autodetect_dev(dev_t dev);
29 * disk_name() is used by partition check code and the genhd driver.
30 * It formats the devicename of the indicated disk into
31 * the supplied buffer (of size at least 32), and returns
32 * a pointer to that same buffer (for convenience).
35 char *disk_name(struct gendisk *hd, int partno, char *buf)
38 snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
39 else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
40 snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
42 snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
47 const char *bdevname(struct block_device *bdev, char *buf)
49 return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
52 EXPORT_SYMBOL(bdevname);
54 const char *bio_devname(struct bio *bio, char *buf)
56 return disk_name(bio->bi_disk, bio->bi_partno, buf);
58 EXPORT_SYMBOL(bio_devname);
61 * There's very little reason to use this, you should really
62 * have a struct block_device just about everywhere and use
65 const char *__bdevname(dev_t dev, char *buffer)
67 scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
68 MAJOR(dev), MINOR(dev));
72 EXPORT_SYMBOL(__bdevname);
74 static ssize_t part_partition_show(struct device *dev,
75 struct device_attribute *attr, char *buf)
77 struct hd_struct *p = dev_to_part(dev);
79 return sprintf(buf, "%d\n", p->partno);
82 static ssize_t part_start_show(struct device *dev,
83 struct device_attribute *attr, char *buf)
85 struct hd_struct *p = dev_to_part(dev);
87 return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
90 ssize_t part_size_show(struct device *dev,
91 struct device_attribute *attr, char *buf)
93 struct hd_struct *p = dev_to_part(dev);
94 return sprintf(buf, "%llu\n",(unsigned long long)part_nr_sects_read(p));
97 static ssize_t part_ro_show(struct device *dev,
98 struct device_attribute *attr, char *buf)
100 struct hd_struct *p = dev_to_part(dev);
101 return sprintf(buf, "%d\n", p->policy ? 1 : 0);
104 static ssize_t part_alignment_offset_show(struct device *dev,
105 struct device_attribute *attr, char *buf)
107 struct hd_struct *p = dev_to_part(dev);
108 return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
111 static ssize_t part_discard_alignment_show(struct device *dev,
112 struct device_attribute *attr, char *buf)
114 struct hd_struct *p = dev_to_part(dev);
115 return sprintf(buf, "%u\n", p->discard_alignment);
118 ssize_t part_stat_show(struct device *dev,
119 struct device_attribute *attr, char *buf)
121 struct hd_struct *p = dev_to_part(dev);
122 struct request_queue *q = part_to_disk(p)->queue;
123 unsigned int inflight;
125 inflight = part_in_flight(q, p);
127 "%8lu %8lu %8llu %8u "
128 "%8lu %8lu %8llu %8u "
130 "%8lu %8lu %8llu %8u"
132 part_stat_read(p, ios[STAT_READ]),
133 part_stat_read(p, merges[STAT_READ]),
134 (unsigned long long)part_stat_read(p, sectors[STAT_READ]),
135 (unsigned int)part_stat_read_msecs(p, STAT_READ),
136 part_stat_read(p, ios[STAT_WRITE]),
137 part_stat_read(p, merges[STAT_WRITE]),
138 (unsigned long long)part_stat_read(p, sectors[STAT_WRITE]),
139 (unsigned int)part_stat_read_msecs(p, STAT_WRITE),
141 jiffies_to_msecs(part_stat_read(p, io_ticks)),
142 jiffies_to_msecs(part_stat_read(p, time_in_queue)),
143 part_stat_read(p, ios[STAT_DISCARD]),
144 part_stat_read(p, merges[STAT_DISCARD]),
145 (unsigned long long)part_stat_read(p, sectors[STAT_DISCARD]),
146 (unsigned int)part_stat_read_msecs(p, STAT_DISCARD));
149 ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
152 struct hd_struct *p = dev_to_part(dev);
153 struct request_queue *q = part_to_disk(p)->queue;
154 unsigned int inflight[2];
156 part_in_flight_rw(q, p, inflight);
157 return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);
160 #ifdef CONFIG_FAIL_MAKE_REQUEST
161 ssize_t part_fail_show(struct device *dev,
162 struct device_attribute *attr, char *buf)
164 struct hd_struct *p = dev_to_part(dev);
166 return sprintf(buf, "%d\n", p->make_it_fail);
169 ssize_t part_fail_store(struct device *dev,
170 struct device_attribute *attr,
171 const char *buf, size_t count)
173 struct hd_struct *p = dev_to_part(dev);
176 if (count > 0 && sscanf(buf, "%d", &i) > 0)
177 p->make_it_fail = (i == 0) ? 0 : 1;
183 static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
184 static DEVICE_ATTR(start, 0444, part_start_show, NULL);
185 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
186 static DEVICE_ATTR(ro, 0444, part_ro_show, NULL);
187 static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL);
188 static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL);
189 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
190 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
191 #ifdef CONFIG_FAIL_MAKE_REQUEST
192 static struct device_attribute dev_attr_fail =
193 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
196 static struct attribute *part_attrs[] = {
197 &dev_attr_partition.attr,
198 &dev_attr_start.attr,
201 &dev_attr_alignment_offset.attr,
202 &dev_attr_discard_alignment.attr,
204 &dev_attr_inflight.attr,
205 #ifdef CONFIG_FAIL_MAKE_REQUEST
211 static struct attribute_group part_attr_group = {
215 static const struct attribute_group *part_attr_groups[] = {
217 #ifdef CONFIG_BLK_DEV_IO_TRACE
218 &blk_trace_attr_group,
223 static void part_release(struct device *dev)
225 struct hd_struct *p = dev_to_part(dev);
226 blk_free_devt(dev->devt);
231 static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
233 struct hd_struct *part = dev_to_part(dev);
235 add_uevent_var(env, "PARTN=%u", part->partno);
236 if (part->info && part->info->volname[0])
237 add_uevent_var(env, "PARTNAME=%s", part->info->volname);
241 struct device_type part_type = {
243 .groups = part_attr_groups,
244 .release = part_release,
245 .uevent = part_uevent,
248 static void delete_partition_work_fn(struct work_struct *work)
250 struct hd_struct *part = container_of(to_rcu_work(work), struct hd_struct,
253 part->start_sect = 0;
255 part_stat_set_all(part, 0);
256 put_device(part_to_dev(part));
259 void __delete_partition(struct percpu_ref *ref)
261 struct hd_struct *part = container_of(ref, struct hd_struct, ref);
262 INIT_RCU_WORK(&part->rcu_work, delete_partition_work_fn);
263 queue_rcu_work(system_wq, &part->rcu_work);
267 * Must be called either with bd_mutex held, before a disk can be opened or
268 * after all disk users are gone.
270 void delete_partition(struct gendisk *disk, int partno)
272 struct disk_part_tbl *ptbl =
273 rcu_dereference_protected(disk->part_tbl, 1);
274 struct hd_struct *part;
276 if (partno >= ptbl->len)
279 part = rcu_dereference_protected(ptbl->part[partno], 1);
283 rcu_assign_pointer(ptbl->part[partno], NULL);
284 rcu_assign_pointer(ptbl->last_lookup, NULL);
285 kobject_put(part->holder_dir);
286 device_del(part_to_dev(part));
289 * Remove gendisk pointer from idr so that it cannot be looked up
290 * while RCU period before freeing gendisk is running to prevent
291 * use-after-free issues. Note that the device number stays
292 * "in-use" until we really free the gendisk.
294 blk_invalidate_devt(part_devt(part));
295 hd_struct_kill(part);
298 static ssize_t whole_disk_show(struct device *dev,
299 struct device_attribute *attr, char *buf)
303 static DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
306 * Must be called either with bd_mutex held, before a disk can be opened or
307 * after all disk users are gone.
309 struct hd_struct *add_partition(struct gendisk *disk, int partno,
310 sector_t start, sector_t len, int flags,
311 struct partition_meta_info *info)
314 dev_t devt = MKDEV(0, 0);
315 struct device *ddev = disk_to_dev(disk);
317 struct disk_part_tbl *ptbl;
321 err = disk_expand_part_tbl(disk, partno);
324 ptbl = rcu_dereference_protected(disk->part_tbl, 1);
326 if (ptbl->part[partno])
327 return ERR_PTR(-EBUSY);
329 p = kzalloc(sizeof(*p), GFP_KERNEL);
331 return ERR_PTR(-EBUSY);
333 if (!init_part_stats(p)) {
338 seqcount_init(&p->nr_sects_seq);
339 pdev = part_to_dev(p);
341 p->start_sect = start;
342 p->alignment_offset =
343 queue_limit_alignment_offset(&disk->queue->limits, start);
344 p->discard_alignment =
345 queue_limit_discard_alignment(&disk->queue->limits, start);
348 p->policy = get_disk_ro(disk);
351 struct partition_meta_info *pinfo = alloc_part_info(disk);
356 memcpy(pinfo, info, sizeof(*info));
360 dname = dev_name(ddev);
361 if (isdigit(dname[strlen(dname) - 1]))
362 dev_set_name(pdev, "%sp%d", dname, partno);
364 dev_set_name(pdev, "%s%d", dname, partno);
366 device_initialize(pdev);
367 pdev->class = &block_class;
368 pdev->type = &part_type;
371 err = blk_alloc_devt(p, &devt);
376 /* delay uevent until 'holders' subdir is created */
377 dev_set_uevent_suppress(pdev, 1);
378 err = device_add(pdev);
383 p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
387 dev_set_uevent_suppress(pdev, 0);
388 if (flags & ADDPART_FLAG_WHOLEDISK) {
389 err = device_create_file(pdev, &dev_attr_whole_disk);
394 err = hd_ref_init(p);
396 if (flags & ADDPART_FLAG_WHOLEDISK)
397 goto out_remove_file;
401 /* everything is up and running, commence */
402 rcu_assign_pointer(ptbl->part[partno], p);
404 /* suppress uevent if the disk suppresses it */
405 if (!dev_get_uevent_suppress(ddev))
406 kobject_uevent(&pdev->kobj, KOBJ_ADD);
417 device_remove_file(pdev, &dev_attr_whole_disk);
419 kobject_put(p->holder_dir);
426 static bool disk_unlock_native_capacity(struct gendisk *disk)
428 const struct block_device_operations *bdops = disk->fops;
430 if (bdops->unlock_native_capacity &&
431 !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
432 printk(KERN_CONT "enabling native capacity\n");
433 bdops->unlock_native_capacity(disk);
434 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
437 printk(KERN_CONT "truncated\n");
442 static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
444 struct disk_part_iter piter;
445 struct hd_struct *part;
448 if (bdev->bd_part_count || bdev->bd_super)
450 res = invalidate_partition(disk, 0);
454 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
455 while ((part = disk_part_iter_next(&piter)))
456 delete_partition(disk, part->partno);
457 disk_part_iter_exit(&piter);
462 static bool part_zone_aligned(struct gendisk *disk,
463 struct block_device *bdev,
464 sector_t from, sector_t size)
466 unsigned int zone_sectors = bdev_zone_sectors(bdev);
469 * If this function is called, then the disk is a zoned block device
470 * (host-aware or host-managed). This can be detected even if the
471 * zoned block device support is disabled (CONFIG_BLK_DEV_ZONED not
472 * set). In this case, however, only host-aware devices will be seen
473 * as a block device is not created for host-managed devices. Without
474 * zoned block device support, host-aware drives can still be used as
475 * regular block devices (no zone operation) and their zone size will
476 * be reported as 0. Allow this case.
482 * Check partition start and size alignement. If the drive has a
483 * smaller last runt zone, ignore it and allow the partition to
484 * use it. Check the zone size too: it should be a power of 2 number
487 if (WARN_ON_ONCE(!is_power_of_2(zone_sectors))) {
490 div_u64_rem(from, zone_sectors, &rem);
493 if ((from + size) < get_capacity(disk)) {
494 div_u64_rem(size, zone_sectors, &rem);
501 if (from & (zone_sectors - 1))
503 if ((from + size) < get_capacity(disk) &&
504 (size & (zone_sectors - 1)))
512 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
514 struct parsed_partitions *state = NULL;
515 struct hd_struct *part;
518 if (state && !IS_ERR(state)) {
519 free_partitions(state);
523 res = drop_partitions(disk, bdev);
527 if (disk->fops->revalidate_disk)
528 disk->fops->revalidate_disk(disk);
529 check_disk_size_change(disk, bdev, true);
530 bdev->bd_invalidated = 0;
531 if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
535 * I/O error reading the partition table. If any
536 * partition code tried to read beyond EOD, retry
537 * after unlocking native capacity.
539 if (PTR_ERR(state) == -ENOSPC) {
540 printk(KERN_WARNING "%s: partition table beyond EOD, ",
542 if (disk_unlock_native_capacity(disk))
548 * If any partition code tried to read beyond EOD, try
549 * unlocking native capacity even if partition table is
550 * successfully read as we could be missing some partitions.
552 if (state->access_beyond_eod) {
554 "%s: partition table partially beyond EOD, ",
556 if (disk_unlock_native_capacity(disk))
560 /* tell userspace that the media / partition table may have changed */
561 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
563 /* Detect the highest partition number and preallocate
564 * disk->part_tbl. This is an optimization and not strictly
567 for (p = 1, highest = 0; p < state->limit; p++)
568 if (state->parts[p].size)
571 disk_expand_part_tbl(disk, highest);
574 for (p = 1; p < state->limit; p++) {
577 size = state->parts[p].size;
581 from = state->parts[p].from;
582 if (from >= get_capacity(disk)) {
584 "%s: p%d start %llu is beyond EOD, ",
585 disk->disk_name, p, (unsigned long long) from);
586 if (disk_unlock_native_capacity(disk))
591 if (from + size > get_capacity(disk)) {
593 "%s: p%d size %llu extends beyond EOD, ",
594 disk->disk_name, p, (unsigned long long) size);
596 if (disk_unlock_native_capacity(disk)) {
597 /* free state and restart */
601 * we can not ignore partitions of broken tables
602 * created by for example camera firmware, but
603 * we limit them to the end of the disk to avoid
604 * creating invalid block devices
606 size = get_capacity(disk) - from;
611 * On a zoned block device, partitions should be aligned on the
612 * device zone size (i.e. zone boundary crossing not allowed).
613 * Otherwise, resetting the write pointer of the last zone of
614 * one partition may impact the following partition.
616 if (bdev_is_zoned(bdev) &&
617 !part_zone_aligned(disk, bdev, from, size)) {
619 "%s: p%d start %llu+%llu is not zone aligned\n",
620 disk->disk_name, p, (unsigned long long) from,
621 (unsigned long long) size);
625 part = add_partition(disk, p, from, size,
626 state->parts[p].flags,
627 &state->parts[p].info);
629 printk(KERN_ERR " %s: p%d could not be added: %ld\n",
630 disk->disk_name, p, -PTR_ERR(part));
633 #ifdef CONFIG_BLK_DEV_MD
634 if (state->parts[p].flags & ADDPART_FLAG_RAID)
635 md_autodetect_dev(part_to_dev(part)->devt);
638 free_partitions(state);
642 int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
646 if (!bdev->bd_invalidated)
649 res = drop_partitions(disk, bdev);
653 set_capacity(disk, 0);
654 check_disk_size_change(disk, bdev, false);
655 bdev->bd_invalidated = 0;
656 /* tell userspace that the media / partition table may have changed */
657 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
662 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
664 struct address_space *mapping = bdev->bd_inode->i_mapping;
667 page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_SHIFT-9)), NULL);
672 return (unsigned char *)page_address(page) + ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << 9);
680 EXPORT_SYMBOL(read_dev_sector);