diff options
Diffstat (limited to 'block/partitions/core.c')
| -rw-r--r-- | block/partitions/core.c | 658 |
1 files changed, 658 insertions, 0 deletions
diff --git a/block/partitions/core.c b/block/partitions/core.c new file mode 100644 index 000000000000..b79c4513629b --- /dev/null +++ b/block/partitions/core.c @@ -0,0 +1,658 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 1991-1998 Linus Torvalds + * Re-organised Feb 1998 Russell King + */ +#include <linux/fs.h> +#include <linux/slab.h> +#include <linux/ctype.h> +#include <linux/genhd.h> +#include <linux/vmalloc.h> +#include <linux/blktrace_api.h> +#include <linux/raid/detect.h> +#include "check.h" + +static int (*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; + + state = kzalloc(sizeof(*state), GFP_KERNEL); + if (!state) + return NULL; + + nr = disk_max_parts(hd); + 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 block_device *bdev) +{ + 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->bdev = bdev; + disk_name(hd, 0, state->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) +{ + struct hd_struct *p = dev_to_part(dev); + + return sprintf(buf, "%d\n", p->partno); +} + +static ssize_t part_start_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct hd_struct *p = dev_to_part(dev); + + return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect); +} + +static ssize_t part_ro_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct hd_struct *p = dev_to_part(dev); + return sprintf(buf, "%d\n", p->policy ? 1 : 0); +} + +static ssize_t part_alignment_offset_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct hd_struct *p = dev_to_part(dev); + return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset); +} + +static ssize_t part_discard_alignment_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct hd_struct *p = dev_to_part(dev); + return sprintf(buf, "%u\n", p->discard_alignment); +} + +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 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) +{ + struct hd_struct *p = dev_to_part(dev); + blk_free_devt(dev->devt); + hd_free_part(p); + kfree(p); +} + +static int part_uevent(struct device *dev, struct kobj_uevent_env *env) +{ + struct hd_struct *part = dev_to_part(dev); + + add_uevent_var(env, "PARTN=%u", part->partno); + if (part->info && part->info->volname[0]) + add_uevent_var(env, "PARTNAME=%s", part->info->volname); + return 0; +} + +struct device_type part_type = { + .name = "partition", + .groups = part_attr_groups, + .release = part_release, + .uevent = part_uevent, +}; + +static void delete_partition_work_fn(struct work_struct *work) +{ + struct hd_struct *part = container_of(to_rcu_work(work), struct hd_struct, + rcu_work); + + part->start_sect = 0; + part->nr_sects = 0; + part_stat_set_all(part, 0); + put_device(part_to_dev(part)); +} + +void __delete_partition(struct percpu_ref *ref) +{ + struct hd_struct *part = container_of(ref, struct hd_struct, ref); + INIT_RCU_WORK(&part->rcu_work, delete_partition_work_fn); + queue_rcu_work(system_wq, &part->rcu_work); +} + +/* + * Must be called either with bd_mutex held, before a disk can be opened or + * after all disk users are gone. + */ +void delete_partition(struct gendisk *disk, int partno) +{ + struct disk_part_tbl *ptbl = + rcu_dereference_protected(disk->part_tbl, 1); + struct hd_struct *part; + + if (partno >= ptbl->len) + return; + + part = rcu_dereference_protected(ptbl->part[partno], 1); + if (!part) + return; + + rcu_assign_pointer(ptbl->part[partno], NULL); + rcu_assign_pointer(ptbl->last_lookup, NULL); + kobject_put(part->holder_dir); + device_del(part_to_dev(part)); + + /* + * Remove gendisk pointer from idr so that it cannot be looked up + * while RCU period before freeing gendisk is running to prevent + * use-after-free issues. Note that the device number stays + * "in-use" until we really free the gendisk. + */ + blk_invalidate_devt(part_devt(part)); + hd_struct_kill(part); +} + +static ssize_t whole_disk_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return 0; +} +static DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL); + +/* + * Must be called either with bd_mutex held, before a disk can be opened or + * after all disk users are gone. + */ +struct hd_struct *add_partition(struct gendisk *disk, int partno, + sector_t start, sector_t len, int flags, + struct partition_meta_info *info) +{ + struct hd_struct *p; + dev_t devt = MKDEV(0, 0); + struct device *ddev = disk_to_dev(disk); + struct device *pdev; + struct disk_part_tbl *ptbl; + const char *dname; + int err; + + /* + * Partitions are not supported on zoned block devices that are used as + * such. + */ + switch (disk->queue->limits.zoned) { + case BLK_ZONED_HM: + pr_warn("%s: partitions not supported on host managed zoned block device\n", + disk->disk_name); + return ERR_PTR(-ENXIO); + case BLK_ZONED_HA: + pr_info("%s: disabling host aware zoned block device support due to partitions\n", + disk->disk_name); + disk->queue->limits.zoned = BLK_ZONED_NONE; + break; + case BLK_ZONED_NONE: + break; + } + + err = disk_expand_part_tbl(disk, partno); + if (err) + return ERR_PTR(err); + ptbl = rcu_dereference_protected(disk->part_tbl, 1); + + if (ptbl->part[partno]) + return ERR_PTR(-EBUSY); + + p = kzalloc(sizeof(*p), GFP_KERNEL); + if (!p) + return ERR_PTR(-EBUSY); + + if (!init_part_stats(p)) { + err = -ENOMEM; + goto out_free; + } + + seqcount_init(&p->nr_sects_seq); + pdev = part_to_dev(p); + + p->start_sect = start; + p->alignment_offset = + queue_limit_alignment_offset(&disk->queue->limits, start); + p->discard_alignment = + queue_limit_discard_alignment(&disk->queue->limits, start); + p->nr_sects = len; + p->partno = partno; + p->policy = get_disk_ro(disk); + + if (info) { + struct partition_meta_info *pinfo; + + pinfo = kzalloc_node(sizeof(*pinfo), GFP_KERNEL, disk->node_id); + if (!pinfo) { + err = -ENOMEM; + goto out_free_stats; + } + memcpy(pinfo, info, sizeof(*info)); + p->info = pinfo; + } + + 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; + + err = blk_alloc_devt(p, &devt); + if (err) + goto out_free_info; + pdev->devt = devt; + + /* delay uevent until 'holders' subdir is created */ + dev_set_uevent_suppress(pdev, 1); + err = device_add(pdev); + if (err) + goto out_put; + + err = -ENOMEM; + p->holder_dir = kobject_create_and_add("holders", &pdev->kobj); + if (!p->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; + } + + err = hd_ref_init(p); + if (err) { + if (flags & ADDPART_FLAG_WHOLEDISK) + goto out_remove_file; + goto out_del; + } + + /* everything is up and running, commence */ + rcu_assign_pointer(ptbl->part[partno], p); + + /* suppress uevent if the disk suppresses it */ + if (!dev_get_uevent_suppress(ddev)) + kobject_uevent(&pdev->kobj, KOBJ_ADD); + return p; + +out_free_info: + kfree(p->info); +out_free_stats: + free_part_stats(p); +out_free: + kfree(p); + return ERR_PTR(err); +out_remove_file: + device_remove_file(pdev, &dev_attr_whole_disk); +out_del: + kobject_put(p->holder_dir); + device_del(pdev); +out_put: + put_device(pdev); + return ERR_PTR(err); +} + +static bool disk_unlock_native_capacity(struct gendisk *disk) +{ + const struct block_device_operations *bdops = disk->fops; + + if (bdops->unlock_native_capacity && + !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) { + printk(KERN_CONT "enabling native capacity\n"); + bdops->unlock_native_capacity(disk); + disk->flags |= GENHD_FL_NATIVE_CAPACITY; + return true; + } else { + printk(KERN_CONT "truncated\n"); + return false; + } +} + +int blk_drop_partitions(struct gendisk *disk, struct block_device *bdev) +{ + struct disk_part_iter piter; + struct hd_struct *part; + int res; + + if (!disk_part_scan_enabled(disk)) + return 0; + if (bdev->bd_part_count || bdev->bd_super) + return -EBUSY; + res = invalidate_partition(disk, 0); + if (res) + return res; + + disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY); + while ((part = disk_part_iter_next(&piter))) + delete_partition(disk, part->partno); + disk_part_iter_exit(&piter); + + return 0; +} + +static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev, + struct parsed_partitions *state, int p) +{ + sector_t size = state->parts[p].size; + sector_t from = state->parts[p].from; + struct hd_struct *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: %ld\n", + disk->disk_name, p, -PTR_ERR(part)); + return true; + } + + if (IS_BUILTIN(CONFIG_BLK_DEV_MD) && + (state->parts[p].flags & ADDPART_FLAG_RAID)) + md_autodetect_dev(part_to_dev(part)->devt); + + return true; +} + +int blk_add_partitions(struct gendisk *disk, struct block_device *bdev) +{ + struct parsed_partitions *state; + int ret = -EAGAIN, p, highest; + + if (!disk_part_scan_enabled(disk)) + return 0; + + state = check_partition(disk, bdev); + 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 (disk->queue->limits.zoned == BLK_ZONED_HM) { + 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); + + /* + * Detect the highest partition number and preallocate disk->part_tbl. + * This is an optimization and not strictly necessary. + */ + for (p = 1, highest = 0; p < state->limit; p++) + if (state->parts[p].size) + highest = p; + disk_expand_part_tbl(disk, highest); + + for (p = 1; p < state->limit; p++) + if (!blk_add_partition(disk, bdev, state, p)) + goto out_free_state; + + ret = 0; +out_free_state: + free_partitions(state); + return ret; +} + +void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p) +{ + struct address_space *mapping = state->bdev->bd_inode->i_mapping; + struct page *page; + + if (n >= get_capacity(state->bdev->bd_disk)) { + state->access_beyond_eod = true; + return NULL; + } + + page = read_mapping_page(mapping, + (pgoff_t)(n >> (PAGE_SHIFT - 9)), NULL); + if (IS_ERR(page)) + goto out; + if (PageError(page)) + goto out_put_page; + + p->v = page; + return (unsigned char *)page_address(page) + + ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << SECTOR_SHIFT); +out_put_page: + put_page(page); +out: + p->v = NULL; + return NULL; +} |