diff options
Diffstat (limited to 'block/partitions/core.c')
| -rw-r--r-- | block/partitions/core.c | 735 |
1 files changed, 735 insertions, 0 deletions
diff --git a/block/partitions/core.c b/block/partitions/core.c new file mode 100644 index 000000000000..5f5ed5c75f04 --- /dev/null +++ b/block/partitions/core.c @@ -0,0 +1,735 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 1991-1998 Linus Torvalds + * Re-organised Feb 1998 Russell King + * Copyright (C) 2020 Christoph Hellwig + */ +#include <linux/fs.h> +#include <linux/major.h> +#include <linux/slab.h> +#include <linux/ctype.h> +#include <linux/vmalloc.h> +#include <linux/raid/detect.h> +#include "check.h" + +static int (*const check_part[])(struct parsed_partitions *) = { + /* + * Probe partition formats with tables at disk address 0 + * that also have an ADFS boot block at 0xdc0. + */ +#ifdef CONFIG_ACORN_PARTITION_ICS + adfspart_check_ICS, +#endif +#ifdef CONFIG_ACORN_PARTITION_POWERTEC + adfspart_check_POWERTEC, +#endif +#ifdef CONFIG_ACORN_PARTITION_EESOX + adfspart_check_EESOX, +#endif + + /* + * Now move on to formats that only have partition info at + * disk address 0xdc0. Since these may also have stale + * PC/BIOS partition tables, they need to come before + * the msdos entry. + */ +#ifdef CONFIG_ACORN_PARTITION_CUMANA + adfspart_check_CUMANA, +#endif +#ifdef CONFIG_ACORN_PARTITION_ADFS + adfspart_check_ADFS, +#endif + +#ifdef CONFIG_CMDLINE_PARTITION + cmdline_partition, +#endif +#ifdef CONFIG_EFI_PARTITION + efi_partition, /* this must come before msdos */ +#endif +#ifdef CONFIG_SGI_PARTITION + sgi_partition, +#endif +#ifdef CONFIG_LDM_PARTITION + ldm_partition, /* this must come before msdos */ +#endif +#ifdef CONFIG_MSDOS_PARTITION + msdos_partition, +#endif +#ifdef CONFIG_OSF_PARTITION + osf_partition, +#endif +#ifdef CONFIG_SUN_PARTITION + sun_partition, +#endif +#ifdef CONFIG_AMIGA_PARTITION + amiga_partition, +#endif +#ifdef CONFIG_ATARI_PARTITION + atari_partition, +#endif +#ifdef CONFIG_MAC_PARTITION + mac_partition, +#endif +#ifdef CONFIG_ULTRIX_PARTITION + ultrix_partition, +#endif +#ifdef CONFIG_IBM_PARTITION + ibm_partition, +#endif +#ifdef CONFIG_KARMA_PARTITION + karma_partition, +#endif +#ifdef CONFIG_SYSV68_PARTITION + sysv68_partition, +#endif + NULL +}; + +static struct parsed_partitions *allocate_partitions(struct gendisk *hd) +{ + struct parsed_partitions *state; + int nr = DISK_MAX_PARTS; + + state = kzalloc(sizeof(*state), GFP_KERNEL); + if (!state) + return NULL; + + state->parts = vzalloc(array_size(nr, sizeof(state->parts[0]))); + if (!state->parts) { + kfree(state); + return NULL; + } + + state->limit = nr; + + return state; +} + +static void free_partitions(struct parsed_partitions *state) +{ + vfree(state->parts); + kfree(state); +} + +static struct parsed_partitions *check_partition(struct gendisk *hd) +{ + struct parsed_partitions *state; + int i, res, err; + + state = allocate_partitions(hd); + if (!state) + return NULL; + state->pp_buf = (char *)__get_free_page(GFP_KERNEL); + if (!state->pp_buf) { + free_partitions(state); + return NULL; + } + state->pp_buf[0] = '\0'; + + state->disk = hd; + snprintf(state->name, BDEVNAME_SIZE, "%s", hd->disk_name); + snprintf(state->pp_buf, PAGE_SIZE, " %s:", state->name); + if (isdigit(state->name[strlen(state->name)-1])) + sprintf(state->name, "p"); + + i = res = err = 0; + while (!res && check_part[i]) { + memset(state->parts, 0, state->limit * sizeof(state->parts[0])); + res = check_part[i++](state); + if (res < 0) { + /* + * We have hit an I/O error which we don't report now. + * But record it, and let the others do their job. + */ + err = res; + res = 0; + } + + } + if (res > 0) { + printk(KERN_INFO "%s", state->pp_buf); + + free_page((unsigned long)state->pp_buf); + return state; + } + if (state->access_beyond_eod) + err = -ENOSPC; + /* + * The partition is unrecognized. So report I/O errors if there were any + */ + if (err) + res = err; + if (res) { + strlcat(state->pp_buf, + " unable to read partition table\n", PAGE_SIZE); + printk(KERN_INFO "%s", state->pp_buf); + } + + free_page((unsigned long)state->pp_buf); + free_partitions(state); + return ERR_PTR(res); +} + +static ssize_t part_partition_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_partno); +} + +static ssize_t part_start_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%llu\n", dev_to_bdev(dev)->bd_start_sect); +} + +static ssize_t part_ro_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", bdev_read_only(dev_to_bdev(dev))); +} + +static ssize_t part_alignment_offset_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%u\n", bdev_alignment_offset(dev_to_bdev(dev))); +} + +static ssize_t part_discard_alignment_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%u\n", bdev_discard_alignment(dev_to_bdev(dev))); +} + +static DEVICE_ATTR(partition, 0444, part_partition_show, NULL); +static DEVICE_ATTR(start, 0444, part_start_show, NULL); +static DEVICE_ATTR(size, 0444, part_size_show, NULL); +static DEVICE_ATTR(ro, 0444, part_ro_show, NULL); +static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL); +static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL); +static DEVICE_ATTR(stat, 0444, part_stat_show, NULL); +static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL); +#ifdef CONFIG_FAIL_MAKE_REQUEST +static struct device_attribute dev_attr_fail = + __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store); +#endif + +static struct attribute *part_attrs[] = { + &dev_attr_partition.attr, + &dev_attr_start.attr, + &dev_attr_size.attr, + &dev_attr_ro.attr, + &dev_attr_alignment_offset.attr, + &dev_attr_discard_alignment.attr, + &dev_attr_stat.attr, + &dev_attr_inflight.attr, +#ifdef CONFIG_FAIL_MAKE_REQUEST + &dev_attr_fail.attr, +#endif + NULL +}; + +static const struct attribute_group part_attr_group = { + .attrs = part_attrs, +}; + +static const struct attribute_group *part_attr_groups[] = { + &part_attr_group, +#ifdef CONFIG_BLK_DEV_IO_TRACE + &blk_trace_attr_group, +#endif + NULL +}; + +static void part_release(struct device *dev) +{ + put_disk(dev_to_bdev(dev)->bd_disk); + iput(dev_to_bdev(dev)->bd_inode); +} + +static int part_uevent(const struct device *dev, struct kobj_uevent_env *env) +{ + const struct block_device *part = dev_to_bdev(dev); + + add_uevent_var(env, "PARTN=%u", part->bd_partno); + if (part->bd_meta_info && part->bd_meta_info->volname[0]) + add_uevent_var(env, "PARTNAME=%s", part->bd_meta_info->volname); + return 0; +} + +const struct device_type part_type = { + .name = "partition", + .groups = part_attr_groups, + .release = part_release, + .uevent = part_uevent, +}; + +void drop_partition(struct block_device *part) +{ + lockdep_assert_held(&part->bd_disk->open_mutex); + + xa_erase(&part->bd_disk->part_tbl, part->bd_partno); + kobject_put(part->bd_holder_dir); + + device_del(&part->bd_device); + put_device(&part->bd_device); +} + +static ssize_t whole_disk_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return 0; +} +static const DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL); + +/* + * Must be called either with open_mutex held, before a disk can be opened or + * after all disk users are gone. + */ +static struct block_device *add_partition(struct gendisk *disk, int partno, + sector_t start, sector_t len, int flags, + struct partition_meta_info *info) +{ + dev_t devt = MKDEV(0, 0); + struct device *ddev = disk_to_dev(disk); + struct device *pdev; + struct block_device *bdev; + const char *dname; + int err; + + lockdep_assert_held(&disk->open_mutex); + + if (partno >= DISK_MAX_PARTS) + return ERR_PTR(-EINVAL); + + /* + * Partitions are not supported on zoned block devices that are used as + * such. + */ + if (bdev_is_zoned(disk->part0)) { + pr_warn("%s: partitions not supported on host managed zoned block device\n", + disk->disk_name); + return ERR_PTR(-ENXIO); + } + + if (xa_load(&disk->part_tbl, partno)) + return ERR_PTR(-EBUSY); + + /* ensure we always have a reference to the whole disk */ + get_device(disk_to_dev(disk)); + + err = -ENOMEM; + bdev = bdev_alloc(disk, partno); + if (!bdev) + goto out_put_disk; + + bdev->bd_start_sect = start; + bdev_set_nr_sectors(bdev, len); + + pdev = &bdev->bd_device; + dname = dev_name(ddev); + if (isdigit(dname[strlen(dname) - 1])) + dev_set_name(pdev, "%sp%d", dname, partno); + else + dev_set_name(pdev, "%s%d", dname, partno); + + device_initialize(pdev); + pdev->class = &block_class; + pdev->type = &part_type; + pdev->parent = ddev; + + /* in consecutive minor range? */ + if (bdev->bd_partno < disk->minors) { + devt = MKDEV(disk->major, disk->first_minor + bdev->bd_partno); + } else { + err = blk_alloc_ext_minor(); + if (err < 0) + goto out_put; + devt = MKDEV(BLOCK_EXT_MAJOR, err); + } + pdev->devt = devt; + + if (info) { + err = -ENOMEM; + bdev->bd_meta_info = kmemdup(info, sizeof(*info), GFP_KERNEL); + if (!bdev->bd_meta_info) + goto out_put; + } + + /* delay uevent until 'holders' subdir is created */ + dev_set_uevent_suppress(pdev, 1); + err = device_add(pdev); + if (err) + goto out_put; + + err = -ENOMEM; + bdev->bd_holder_dir = kobject_create_and_add("holders", &pdev->kobj); + if (!bdev->bd_holder_dir) + goto out_del; + + dev_set_uevent_suppress(pdev, 0); + if (flags & ADDPART_FLAG_WHOLEDISK) { + err = device_create_file(pdev, &dev_attr_whole_disk); + if (err) + goto out_del; + } + + /* everything is up and running, commence */ + err = xa_insert(&disk->part_tbl, partno, bdev, GFP_KERNEL); + if (err) + goto out_del; + bdev_add(bdev, devt); + + /* suppress uevent if the disk suppresses it */ + if (!dev_get_uevent_suppress(ddev)) + kobject_uevent(&pdev->kobj, KOBJ_ADD); + return bdev; + +out_del: + kobject_put(bdev->bd_holder_dir); + device_del(pdev); +out_put: + put_device(pdev); + return ERR_PTR(err); +out_put_disk: + put_disk(disk); + return ERR_PTR(err); +} + +static bool partition_overlaps(struct gendisk *disk, sector_t start, + sector_t length, int skip_partno) +{ + struct block_device *part; + bool overlap = false; + unsigned long idx; + + rcu_read_lock(); + xa_for_each_start(&disk->part_tbl, idx, part, 1) { + if (part->bd_partno != skip_partno && + start < part->bd_start_sect + bdev_nr_sectors(part) && + start + length > part->bd_start_sect) { + overlap = true; + break; + } + } + rcu_read_unlock(); + + return overlap; +} + +int bdev_add_partition(struct gendisk *disk, int partno, sector_t start, + sector_t length) +{ + sector_t capacity = get_capacity(disk), end; + struct block_device *part; + int ret; + + mutex_lock(&disk->open_mutex); + if (check_add_overflow(start, length, &end)) { + ret = -EINVAL; + goto out; + } + + if (start >= capacity || end > capacity) { + ret = -EINVAL; + goto out; + } + + if (!disk_live(disk)) { + ret = -ENXIO; + goto out; + } + + if (disk->flags & GENHD_FL_NO_PART) { + ret = -EINVAL; + goto out; + } + + if (partition_overlaps(disk, start, length, -1)) { + ret = -EBUSY; + goto out; + } + + part = add_partition(disk, partno, start, length, + ADDPART_FLAG_NONE, NULL); + ret = PTR_ERR_OR_ZERO(part); +out: + mutex_unlock(&disk->open_mutex); + return ret; +} + +int bdev_del_partition(struct gendisk *disk, int partno) +{ + struct block_device *part = NULL; + int ret = -ENXIO; + + mutex_lock(&disk->open_mutex); + part = xa_load(&disk->part_tbl, partno); + if (!part) + goto out_unlock; + + ret = -EBUSY; + if (atomic_read(&part->bd_openers)) + goto out_unlock; + + /* + * We verified that @part->bd_openers is zero above and so + * @part->bd_holder{_ops} can't be set. And since we hold + * @disk->open_mutex the device can't be claimed by anyone. + * + * So no need to call @part->bd_holder_ops->mark_dead() here. + * Just delete the partition and invalidate it. + */ + + remove_inode_hash(part->bd_inode); + invalidate_bdev(part); + drop_partition(part); + ret = 0; +out_unlock: + mutex_unlock(&disk->open_mutex); + return ret; +} + +int bdev_resize_partition(struct gendisk *disk, int partno, sector_t start, + sector_t length) +{ + struct block_device *part = NULL; + int ret = -ENXIO; + + mutex_lock(&disk->open_mutex); + part = xa_load(&disk->part_tbl, partno); + if (!part) + goto out_unlock; + + ret = -EINVAL; + if (start != part->bd_start_sect) + goto out_unlock; + + ret = -EBUSY; + if (partition_overlaps(disk, start, length, partno)) + goto out_unlock; + + bdev_set_nr_sectors(part, length); + + ret = 0; +out_unlock: + mutex_unlock(&disk->open_mutex); + return ret; +} + +static bool disk_unlock_native_capacity(struct gendisk *disk) +{ + if (!disk->fops->unlock_native_capacity || + test_and_set_bit(GD_NATIVE_CAPACITY, &disk->state)) { + printk(KERN_CONT "truncated\n"); + return false; + } + + printk(KERN_CONT "enabling native capacity\n"); + disk->fops->unlock_native_capacity(disk); + return true; +} + +static bool blk_add_partition(struct gendisk *disk, + struct parsed_partitions *state, int p) +{ + sector_t size = state->parts[p].size; + sector_t from = state->parts[p].from; + struct block_device *part; + + if (!size) + return true; + + if (from >= get_capacity(disk)) { + printk(KERN_WARNING + "%s: p%d start %llu is beyond EOD, ", + disk->disk_name, p, (unsigned long long) from); + if (disk_unlock_native_capacity(disk)) + return false; + return true; + } + + if (from + size > get_capacity(disk)) { + printk(KERN_WARNING + "%s: p%d size %llu extends beyond EOD, ", + disk->disk_name, p, (unsigned long long) size); + + if (disk_unlock_native_capacity(disk)) + return false; + + /* + * We can not ignore partitions of broken tables created by for + * example camera firmware, but we limit them to the end of the + * disk to avoid creating invalid block devices. + */ + size = get_capacity(disk) - from; + } + + part = add_partition(disk, p, from, size, state->parts[p].flags, + &state->parts[p].info); + if (IS_ERR(part) && PTR_ERR(part) != -ENXIO) { + printk(KERN_ERR " %s: p%d could not be added: %pe\n", + disk->disk_name, p, part); + return true; + } + + if (IS_BUILTIN(CONFIG_BLK_DEV_MD) && + (state->parts[p].flags & ADDPART_FLAG_RAID)) + md_autodetect_dev(part->bd_dev); + + return true; +} + +static int blk_add_partitions(struct gendisk *disk) +{ + struct parsed_partitions *state; + int ret = -EAGAIN, p; + + if (disk->flags & GENHD_FL_NO_PART) + return 0; + + if (test_bit(GD_SUPPRESS_PART_SCAN, &disk->state)) + return 0; + + state = check_partition(disk); + if (!state) + return 0; + if (IS_ERR(state)) { + /* + * I/O error reading the partition table. If we tried to read + * beyond EOD, retry after unlocking the native capacity. + */ + if (PTR_ERR(state) == -ENOSPC) { + printk(KERN_WARNING "%s: partition table beyond EOD, ", + disk->disk_name); + if (disk_unlock_native_capacity(disk)) + return -EAGAIN; + } + return -EIO; + } + + /* + * Partitions are not supported on host managed zoned block devices. + */ + if (bdev_is_zoned(disk->part0)) { + pr_warn("%s: ignoring partition table on host managed zoned block device\n", + disk->disk_name); + ret = 0; + goto out_free_state; + } + + /* + * If we read beyond EOD, try unlocking native capacity even if the + * partition table was successfully read as we could be missing some + * partitions. + */ + if (state->access_beyond_eod) { + printk(KERN_WARNING + "%s: partition table partially beyond EOD, ", + disk->disk_name); + if (disk_unlock_native_capacity(disk)) + goto out_free_state; + } + + /* tell userspace that the media / partition table may have changed */ + kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE); + + for (p = 1; p < state->limit; p++) + if (!blk_add_partition(disk, state, p)) + goto out_free_state; + + ret = 0; +out_free_state: + free_partitions(state); + return ret; +} + +int bdev_disk_changed(struct gendisk *disk, bool invalidate) +{ + struct block_device *part; + unsigned long idx; + int ret = 0; + + lockdep_assert_held(&disk->open_mutex); + + if (!disk_live(disk)) + return -ENXIO; + +rescan: + if (disk->open_partitions) + return -EBUSY; + sync_blockdev(disk->part0); + invalidate_bdev(disk->part0); + + xa_for_each_start(&disk->part_tbl, idx, part, 1) { + /* + * Remove the block device from the inode hash, so that + * it cannot be looked up any more even when openers + * still hold references. + */ + remove_inode_hash(part->bd_inode); + + /* + * If @disk->open_partitions isn't elevated but there's + * still an active holder of that block device things + * are broken. + */ + WARN_ON_ONCE(atomic_read(&part->bd_openers)); + invalidate_bdev(part); + drop_partition(part); + } + clear_bit(GD_NEED_PART_SCAN, &disk->state); + + /* + * Historically we only set the capacity to zero for devices that + * support partitions (independ of actually having partitions created). + * Doing that is rather inconsistent, but changing it broke legacy + * udisks polling for legacy ide-cdrom devices. Use the crude check + * below to get the sane behavior for most device while not breaking + * userspace for this particular setup. + */ + if (invalidate) { + if (!(disk->flags & GENHD_FL_NO_PART) || + !(disk->flags & GENHD_FL_REMOVABLE)) + set_capacity(disk, 0); + } + + if (get_capacity(disk)) { + ret = blk_add_partitions(disk); + if (ret == -EAGAIN) + goto rescan; + } else if (invalidate) { + /* + * Tell userspace that the media / partition table may have + * changed. + */ + kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE); + } + + return ret; +} +/* + * Only exported for loop and dasd for historic reasons. Don't use in new + * code! + */ +EXPORT_SYMBOL_GPL(bdev_disk_changed); + +void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p) +{ + struct address_space *mapping = state->disk->part0->bd_inode->i_mapping; + struct folio *folio; + + if (n >= get_capacity(state->disk)) { + state->access_beyond_eod = true; + goto out; + } + + folio = read_mapping_folio(mapping, n >> PAGE_SECTORS_SHIFT, NULL); + if (IS_ERR(folio)) + goto out; + + p->v = folio; + return folio_address(folio) + offset_in_folio(folio, n * SECTOR_SIZE); +out: + p->v = NULL; + return NULL; +} |