2 * Code extracted from drivers/block/genhd.c
3 * Copyright (C) 1991-1998 Linus Torvalds
4 * Re-organised Feb 1998 Russell King
6 * We now have independent partition support from the
7 * block drivers, which allows all the partition code to
8 * be grouped in one location, and it to be mostly self
12 #include <linux/init.h>
13 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/kmod.h>
17 #include <linux/ctype.h>
18 #include <linux/genhd.h>
19 #include <linux/dax.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);
55 * There's very little reason to use this, you should really
56 * have a struct block_device just about everywhere and use
59 const char *__bdevname(dev_t dev, char *buffer)
61 scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
62 MAJOR(dev), MINOR(dev));
66 EXPORT_SYMBOL(__bdevname);
68 static ssize_t part_partition_show(struct device *dev,
69 struct device_attribute *attr, char *buf)
71 struct hd_struct *p = dev_to_part(dev);
73 return sprintf(buf, "%d\n", p->partno);
76 static ssize_t part_start_show(struct device *dev,
77 struct device_attribute *attr, char *buf)
79 struct hd_struct *p = dev_to_part(dev);
81 return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
84 ssize_t part_size_show(struct device *dev,
85 struct device_attribute *attr, char *buf)
87 struct hd_struct *p = dev_to_part(dev);
88 return sprintf(buf, "%llu\n",(unsigned long long)part_nr_sects_read(p));
91 static ssize_t part_ro_show(struct device *dev,
92 struct device_attribute *attr, char *buf)
94 struct hd_struct *p = dev_to_part(dev);
95 return sprintf(buf, "%d\n", p->policy ? 1 : 0);
98 static ssize_t part_alignment_offset_show(struct device *dev,
99 struct device_attribute *attr, char *buf)
101 struct hd_struct *p = dev_to_part(dev);
102 return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
105 static ssize_t part_discard_alignment_show(struct device *dev,
106 struct device_attribute *attr, char *buf)
108 struct hd_struct *p = dev_to_part(dev);
109 return sprintf(buf, "%u\n", p->discard_alignment);
112 ssize_t part_stat_show(struct device *dev,
113 struct device_attribute *attr, char *buf)
115 struct hd_struct *p = dev_to_part(dev);
118 cpu = part_stat_lock();
119 part_round_stats(cpu, p);
122 "%8lu %8lu %8llu %8u "
123 "%8lu %8lu %8llu %8u "
126 part_stat_read(p, ios[READ]),
127 part_stat_read(p, merges[READ]),
128 (unsigned long long)part_stat_read(p, sectors[READ]),
129 jiffies_to_msecs(part_stat_read(p, ticks[READ])),
130 part_stat_read(p, ios[WRITE]),
131 part_stat_read(p, merges[WRITE]),
132 (unsigned long long)part_stat_read(p, sectors[WRITE]),
133 jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
135 jiffies_to_msecs(part_stat_read(p, io_ticks)),
136 jiffies_to_msecs(part_stat_read(p, time_in_queue)));
139 ssize_t part_inflight_show(struct device *dev,
140 struct device_attribute *attr, char *buf)
142 struct hd_struct *p = dev_to_part(dev);
144 return sprintf(buf, "%8u %8u\n", atomic_read(&p->in_flight[0]),
145 atomic_read(&p->in_flight[1]));
148 #ifdef CONFIG_FAIL_MAKE_REQUEST
149 ssize_t part_fail_show(struct device *dev,
150 struct device_attribute *attr, char *buf)
152 struct hd_struct *p = dev_to_part(dev);
154 return sprintf(buf, "%d\n", p->make_it_fail);
157 ssize_t part_fail_store(struct device *dev,
158 struct device_attribute *attr,
159 const char *buf, size_t count)
161 struct hd_struct *p = dev_to_part(dev);
164 if (count > 0 && sscanf(buf, "%d", &i) > 0)
165 p->make_it_fail = (i == 0) ? 0 : 1;
171 static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
172 static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
173 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
174 static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
175 static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
176 static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
178 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
179 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
180 #ifdef CONFIG_FAIL_MAKE_REQUEST
181 static struct device_attribute dev_attr_fail =
182 __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
185 static struct attribute *part_attrs[] = {
186 &dev_attr_partition.attr,
187 &dev_attr_start.attr,
190 &dev_attr_alignment_offset.attr,
191 &dev_attr_discard_alignment.attr,
193 &dev_attr_inflight.attr,
194 #ifdef CONFIG_FAIL_MAKE_REQUEST
200 static struct attribute_group part_attr_group = {
204 static const struct attribute_group *part_attr_groups[] = {
206 #ifdef CONFIG_BLK_DEV_IO_TRACE
207 &blk_trace_attr_group,
212 static void part_release(struct device *dev)
214 struct hd_struct *p = dev_to_part(dev);
215 blk_free_devt(dev->devt);
220 static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
222 struct hd_struct *part = dev_to_part(dev);
224 add_uevent_var(env, "PARTN=%u", part->partno);
225 if (part->info && part->info->volname[0])
226 add_uevent_var(env, "PARTNAME=%s", part->info->volname);
230 struct device_type part_type = {
232 .groups = part_attr_groups,
233 .release = part_release,
234 .uevent = part_uevent,
237 static void delete_partition_rcu_cb(struct rcu_head *head)
239 struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
241 part->start_sect = 0;
243 part_stat_set_all(part, 0);
244 put_device(part_to_dev(part));
247 void __delete_partition(struct percpu_ref *ref)
249 struct hd_struct *part = container_of(ref, struct hd_struct, ref);
250 call_rcu(&part->rcu_head, delete_partition_rcu_cb);
253 void delete_partition(struct gendisk *disk, int partno)
255 struct disk_part_tbl *ptbl = disk->part_tbl;
256 struct hd_struct *part;
257 struct block_device *bdev;
259 if (partno >= ptbl->len)
262 part = ptbl->part[partno];
266 rcu_assign_pointer(ptbl->part[partno], NULL);
267 rcu_assign_pointer(ptbl->last_lookup, NULL);
268 kobject_put(part->holder_dir);
269 device_del(part_to_dev(part));
271 bdev = bdget(part_devt(part));
273 remove_inode_hash(bdev->bd_inode);
276 hd_struct_kill(part);
279 static ssize_t whole_disk_show(struct device *dev,
280 struct device_attribute *attr, char *buf)
284 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
285 whole_disk_show, NULL);
287 struct hd_struct *add_partition(struct gendisk *disk, int partno,
288 sector_t start, sector_t len, int flags,
289 struct partition_meta_info *info)
292 dev_t devt = MKDEV(0, 0);
293 struct device *ddev = disk_to_dev(disk);
295 struct disk_part_tbl *ptbl;
299 err = disk_expand_part_tbl(disk, partno);
302 ptbl = disk->part_tbl;
304 if (ptbl->part[partno])
305 return ERR_PTR(-EBUSY);
307 p = kzalloc(sizeof(*p), GFP_KERNEL);
309 return ERR_PTR(-EBUSY);
311 if (!init_part_stats(p)) {
316 seqcount_init(&p->nr_sects_seq);
317 pdev = part_to_dev(p);
319 p->start_sect = start;
320 p->alignment_offset =
321 queue_limit_alignment_offset(&disk->queue->limits, start);
322 p->discard_alignment =
323 queue_limit_discard_alignment(&disk->queue->limits, start);
326 p->policy = get_disk_ro(disk);
329 struct partition_meta_info *pinfo = alloc_part_info(disk);
334 memcpy(pinfo, info, sizeof(*info));
338 dname = dev_name(ddev);
339 if (isdigit(dname[strlen(dname) - 1]))
340 dev_set_name(pdev, "%sp%d", dname, partno);
342 dev_set_name(pdev, "%s%d", dname, partno);
344 device_initialize(pdev);
345 pdev->class = &block_class;
346 pdev->type = &part_type;
349 err = blk_alloc_devt(p, &devt);
354 /* delay uevent until 'holders' subdir is created */
355 dev_set_uevent_suppress(pdev, 1);
356 err = device_add(pdev);
361 p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
365 dev_set_uevent_suppress(pdev, 0);
366 if (flags & ADDPART_FLAG_WHOLEDISK) {
367 err = device_create_file(pdev, &dev_attr_whole_disk);
372 err = hd_ref_init(p);
374 if (flags & ADDPART_FLAG_WHOLEDISK)
375 goto out_remove_file;
379 /* everything is up and running, commence */
380 rcu_assign_pointer(ptbl->part[partno], p);
382 /* suppress uevent if the disk suppresses it */
383 if (!dev_get_uevent_suppress(ddev))
384 kobject_uevent(&pdev->kobj, KOBJ_ADD);
395 device_remove_file(pdev, &dev_attr_whole_disk);
397 kobject_put(p->holder_dir);
405 static bool disk_unlock_native_capacity(struct gendisk *disk)
407 const struct block_device_operations *bdops = disk->fops;
409 if (bdops->unlock_native_capacity &&
410 !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
411 printk(KERN_CONT "enabling native capacity\n");
412 bdops->unlock_native_capacity(disk);
413 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
416 printk(KERN_CONT "truncated\n");
421 static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
423 struct disk_part_iter piter;
424 struct hd_struct *part;
427 if (bdev->bd_part_count || bdev->bd_super)
429 res = invalidate_partition(disk, 0);
433 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
434 while ((part = disk_part_iter_next(&piter)))
435 delete_partition(disk, part->partno);
436 disk_part_iter_exit(&piter);
441 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
443 struct parsed_partitions *state = NULL;
444 struct hd_struct *part;
447 if (state && !IS_ERR(state)) {
448 free_partitions(state);
452 res = drop_partitions(disk, bdev);
456 if (disk->fops->revalidate_disk)
457 disk->fops->revalidate_disk(disk);
458 check_disk_size_change(disk, bdev);
459 bdev->bd_invalidated = 0;
460 if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
464 * I/O error reading the partition table. If any
465 * partition code tried to read beyond EOD, retry
466 * after unlocking native capacity.
468 if (PTR_ERR(state) == -ENOSPC) {
469 printk(KERN_WARNING "%s: partition table beyond EOD, ",
471 if (disk_unlock_native_capacity(disk))
477 * If any partition code tried to read beyond EOD, try
478 * unlocking native capacity even if partition table is
479 * successfully read as we could be missing some partitions.
481 if (state->access_beyond_eod) {
483 "%s: partition table partially beyond EOD, ",
485 if (disk_unlock_native_capacity(disk))
489 /* tell userspace that the media / partition table may have changed */
490 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
492 /* Detect the highest partition number and preallocate
493 * disk->part_tbl. This is an optimization and not strictly
496 for (p = 1, highest = 0; p < state->limit; p++)
497 if (state->parts[p].size)
500 disk_expand_part_tbl(disk, highest);
503 for (p = 1; p < state->limit; p++) {
506 size = state->parts[p].size;
510 from = state->parts[p].from;
511 if (from >= get_capacity(disk)) {
513 "%s: p%d start %llu is beyond EOD, ",
514 disk->disk_name, p, (unsigned long long) from);
515 if (disk_unlock_native_capacity(disk))
520 if (from + size > get_capacity(disk)) {
522 "%s: p%d size %llu extends beyond EOD, ",
523 disk->disk_name, p, (unsigned long long) size);
525 if (disk_unlock_native_capacity(disk)) {
526 /* free state and restart */
530 * we can not ignore partitions of broken tables
531 * created by for example camera firmware, but
532 * we limit them to the end of the disk to avoid
533 * creating invalid block devices
535 size = get_capacity(disk) - from;
539 part = add_partition(disk, p, from, size,
540 state->parts[p].flags,
541 &state->parts[p].info);
543 printk(KERN_ERR " %s: p%d could not be added: %ld\n",
544 disk->disk_name, p, -PTR_ERR(part));
547 #ifdef CONFIG_BLK_DEV_MD
548 if (state->parts[p].flags & ADDPART_FLAG_RAID)
549 md_autodetect_dev(part_to_dev(part)->devt);
552 free_partitions(state);
556 int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
560 if (!bdev->bd_invalidated)
563 res = drop_partitions(disk, bdev);
567 set_capacity(disk, 0);
568 check_disk_size_change(disk, bdev);
569 bdev->bd_invalidated = 0;
570 /* tell userspace that the media / partition table may have changed */
571 kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
576 static struct page *read_pagecache_sector(struct block_device *bdev, sector_t n)
578 struct address_space *mapping = bdev->bd_inode->i_mapping;
580 return read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_SHIFT-9)),
584 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
588 /* don't populate page cache for dax capable devices */
589 if (IS_DAX(bdev->bd_inode))
590 page = read_dax_sector(bdev, n);
592 page = read_pagecache_sector(bdev, n);
598 return (unsigned char *)page_address(page) + ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << 9);
606 EXPORT_SYMBOL(read_dev_sector);