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-rw-r--r--block/partitions/core.c731
1 files changed, 731 insertions, 0 deletions
diff --git a/block/partitions/core.c b/block/partitions/core.c
new file mode 100644
index 000000000..3927f4283
--- /dev/null
+++ b/block/partitions/core.c
@@ -0,0 +1,731 @@
+// 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 (*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 void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors)
+{
+ spin_lock(&bdev->bd_size_lock);
+ i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
+ bdev->bd_nr_sectors = sectors;
+ spin_unlock(&bdev->bd_size_lock);
+}
+
+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 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(struct device *dev, struct kobj_uevent_env *env)
+{
+ 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;
+}
+
+struct device_type part_type = {
+ .name = "partition",
+ .groups = part_attr_groups,
+ .release = part_release,
+ .uevent = part_uevent,
+};
+
+static void delete_partition(struct block_device *part)
+{
+ lockdep_assert_held(&part->bd_disk->open_mutex);
+
+ fsync_bdev(part);
+ __invalidate_device(part, true);
+
+ xa_erase(&part->bd_disk->part_tbl, part->bd_partno);
+ kobject_put(part->bd_holder_dir);
+ device_del(&part->bd_device);
+
+ /*
+ * 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);
+
+ put_device(&part->bd_device);
+}
+
+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 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.
+ */
+ 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_set_zoned(disk, BLK_ZONED_NONE);
+ break;
+ case BLK_ZONED_NONE:
+ break;
+ }
+
+ 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)
+{
+ struct block_device *part;
+ int ret;
+
+ mutex_lock(&disk->open_mutex);
+ 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;
+
+ delete_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;
+}
+
+void blk_drop_partitions(struct gendisk *disk)
+{
+ struct block_device *part;
+ unsigned long idx;
+
+ lockdep_assert_held(&disk->open_mutex);
+
+ xa_for_each_start(&disk->part_tbl, idx, part, 1)
+ delete_partition(part);
+}
+
+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: %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->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 (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);
+
+ 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)
+{
+ 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);
+ blk_drop_partitions(disk);
+
+ 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;
+}
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