[PATCH 01/10] block: refactor blkpg_ioctl

Christoph Hellwig
2020-04-14T07:29:11Z

Split each sub-command out into a separate helper, and move those helpers
to block/partitions/core.c instead of having a lot of partition
manipulation logic open coded in block/ioctl.c.

Signed-off-by: Christoph Hellwig <hch@lst.de
---
block/blk.h | 8 ++-
block/ioctl.c | 150 +++++++---------------------------------
block/partitions/core.c | 115 +++++++++++++++++++++++++++++-
3 files changed, 145 insertions(+), 128 deletions(-)

diff --git a/block/blk.h b/block/blk.h
index 0a94ec68af32..305e0ac22bf7 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -389,11 +389,13 @@ char *disk_name(struct gendisk *hd, int partno, char *buf);
#define ADDPART_FLAG_NONE 0
#define ADDPART_FLAG_RAID 1
#define ADDPART_FLAG_WHOLEDISK 2
-struct hd_struct *__must_check add_partition(struct gendisk *disk, int partno,
- sector_t start, sector_t len, int flags,
- struct partition_meta_info *info);
void __delete_partition(struct percpu_ref *ref);
void delete_partition(struct gendisk *disk, int partno);
+int bdev_add_partition(struct block_device *bdev, int partno,
+ sector_t start, sector_t length);
+int bdev_del_partition(struct block_device *bdev, int partno);
+int bdev_resize_partition(struct block_device *bdev, int partno,
+ sector_t start, sector_t length);
int disk_expand_part_tbl(struct gendisk *disk, int target);

static inline int hd_ref_init(struct hd_struct *part)
diff --git a/block/ioctl.c b/block/ioctl.c
index 6e827de1a4c4..75c64811b534 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -16,142 +16,44 @@
static int blkpg_do_ioctl(struct block_device *bdev,
struct blkpg_partition __user *upart, int op)
{
- struct block_device *bdevp;
- struct gendisk *disk;
- struct hd_struct *part, *lpart;
struct blkpg_partition p;
- struct disk_part_iter piter;
long long start, length;
- int partno;

if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (copy_from_user(&p, upart, sizeof(struct blkpg_partition)))
return -EFAULT;
- disk = bdev->bd_disk;
if (bdev != bdev->bd_contains)
return -EINVAL;
- partno = p.pno;
- if (partno <= 0)
+
+ if (p.pno <= 0)
return -EINVAL;
+
+ if (op == BLKPG_DEL_PARTITION)
+ return bdev_del_partition(bdev, p.pno);
+
+ start = p.start >> SECTOR_SHIFT;
+ length = p.length >> SECTOR_SHIFT;
+
+ /* check for fit in a hd_struct */
+ if (sizeof(sector_t) < sizeof(long long)) {
+ long pstart = start, plength = length;
+
+ if (pstart != start || plength != length || pstart < 0 ||
+ plength < 0 || p.pno > 65535)
+ return -EINVAL;
+ }
+
switch (op) {
- case BLKPG_ADD_PARTITION:
- start = p.start >> 9;
- length = p.length >> 9;
- /* check for fit in a hd_struct */
- if (sizeof(sector_t) == sizeof(long) &&
- sizeof(long long) > sizeof(long)) {
- long pstart = start, plength = length;
- if (pstart != start || plength != length
- || pstart < 0 || plength < 0 || partno > 65535)
- return -EINVAL;
- }
- /* check if partition is aligned to blocksize */
- if (p.start & (bdev_logical_block_size(bdev) - 1))
- return -EINVAL;
-
- mutex_lock(&bdev->bd_mutex);
-
- /* overlap? */
- disk_part_iter_init(&piter, disk,
- DISK_PITER_INCL_EMPTY);
- while ((part = disk_part_iter_next(&piter))) {
- if (!(start + length <= part->start_sect ||
- start >= part->start_sect + part->nr_sects)) {
- disk_part_iter_exit(&piter);
- mutex_unlock(&bdev->bd_mutex);
- return -EBUSY;
- }
- }
- disk_part_iter_exit(&piter);
-
- /* all seems OK */
- part = add_partition(disk, partno, start, length,
- ADDPART_FLAG_NONE, NULL);
- mutex_unlock(&bdev->bd_mutex);
- return PTR_ERR_OR_ZERO(part);
- case BLKPG_DEL_PARTITION:
- part = disk_get_part(disk, partno);
- if (!part)
- return -ENXIO;
-
- bdevp = bdget(part_devt(part));
- disk_put_part(part);
- if (!bdevp)
- return -ENOMEM;
-
- mutex_lock(&bdevp->bd_mutex);
- if (bdevp->bd_openers) {
- mutex_unlock(&bdevp->bd_mutex);
- bdput(bdevp);
- return -EBUSY;
- }
- /* all seems OK */
- fsync_bdev(bdevp);
- invalidate_bdev(bdevp);
-
- mutex_lock_nested(&bdev->bd_mutex, 1);
- delete_partition(disk, partno);
- mutex_unlock(&bdev->bd_mutex);
- mutex_unlock(&bdevp->bd_mutex);
- bdput(bdevp);
-
- return 0;
- case BLKPG_RESIZE_PARTITION:
- start = p.start >> 9;
- /* new length of partition in bytes */
- length = p.length >> 9;
- /* check for fit in a hd_struct */
- if (sizeof(sector_t) == sizeof(long) &&
- sizeof(long long) > sizeof(long)) {
- long pstart = start, plength = length;
- if (pstart != start || plength != length
- || pstart < 0 || plength < 0)
- return -EINVAL;
- }
- part = disk_get_part(disk, partno);
- if (!part)
- return -ENXIO;
- bdevp = bdget(part_devt(part));
- if (!bdevp) {
- disk_put_part(part);
- return -ENOMEM;
- }
- mutex_lock(&bdevp->bd_mutex);
- mutex_lock_nested(&bdev->bd_mutex, 1);
- if (start != part->start_sect) {
- mutex_unlock(&bdevp->bd_mutex);
- mutex_unlock(&bdev->bd_mutex);
- bdput(bdevp);
- disk_put_part(part);
- return -EINVAL;
- }
- /* overlap? */
- disk_part_iter_init(&piter, disk,
- DISK_PITER_INCL_EMPTY);
- while ((lpart = disk_part_iter_next(&piter))) {
- if (lpart->partno != partno &&
- !(start + length <= lpart->start_sect ||
- start >= lpart->start_sect + lpart->nr_sects)
- ) {
- disk_part_iter_exit(&piter);
- mutex_unlock(&bdevp->bd_mutex);
- mutex_unlock(&bdev->bd_mutex);
- bdput(bdevp);
- disk_put_part(part);
- return -EBUSY;
- }
- }
- disk_part_iter_exit(&piter);
- part_nr_sects_write(part, (sector_t)length);
- i_size_write(bdevp->bd_inode, p.length);
- mutex_unlock(&bdevp->bd_mutex);
- mutex_unlock(&bdev->bd_mutex);
- bdput(bdevp);
- disk_put_part(part);
- return 0;
- default:
+ case BLKPG_ADD_PARTITION:
+ /* check if partition is aligned to blocksize */
+ if (p.start & (bdev_logical_block_size(bdev) - 1))
return -EINVAL;
+ return bdev_add_partition(bdev, p.pno, start, length);
+ case BLKPG_RESIZE_PARTITION:
+ return bdev_resize_partition(bdev, p.pno, start, length);
+ default:
+ return -EINVAL;
}
}

diff --git a/block/partitions/core.c b/block/partitions/core.c
index bc1ded1331b1..7e2f40875166 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -335,7 +335,7 @@ 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,
+static struct hd_struct *add_partition(struct gendisk *disk, int partno,
sector_t start, sector_t len, int flags,
struct partition_meta_info *info)
{
@@ -472,6 +472,119 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
return ERR_PTR(err);
}

+static bool partition_overlaps(struct gendisk *disk, sector_t start,
+ sector_t length, int skip_partno)
+{
+ struct disk_part_iter piter;
+ struct hd_struct *part;
+ bool overlap = false;
+
+ disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
+ while ((part = disk_part_iter_next(&piter))) {
+ if (part->partno == skip_partno ||
+ start >= part->start_sect + part->nr_sects ||
+ start + length <= part->start_sect)
+ continue;
+ overlap = true;
+ break;
+ }
+
+ disk_part_iter_exit(&piter);
+ return overlap;
+}
+
+int bdev_add_partition(struct block_device *bdev, int partno,
+ sector_t start, sector_t length)
+{
+ struct hd_struct *part;
+
+ mutex_lock(&bdev->bd_mutex);
+ if (partition_overlaps(bdev->bd_disk, start, length, -1)) {
+ mutex_unlock(&bdev->bd_mutex);
+ return -EBUSY;
+ }
+
+ part = add_partition(bdev->bd_disk, partno, start, length,
+ ADDPART_FLAG_NONE, NULL);
+ mutex_unlock(&bdev->bd_mutex);
+ return PTR_ERR_OR_ZERO(part);
+}
+
+int bdev_del_partition(struct block_device *bdev, int partno)
+{
+ struct block_device *bdevp;
+ struct hd_struct *part;
+ int ret = 0;
+
+ part = disk_get_part(bdev->bd_disk, partno);
+ if (!part)
+ return -ENXIO;
+
+ bdevp = bdget(part_devt(part));
+ disk_put_part(part);
+ if (!bdevp)
+ return -ENOMEM;
+
+ mutex_lock(&bdevp->bd_mutex);
+
+ ret = -EBUSY;
+ if (bdevp->bd_openers)
+ goto out_unlock;
+
+ fsync_bdev(bdevp);
+ invalidate_bdev(bdevp);
+
+ mutex_lock_nested(&bdev->bd_mutex, 1);
+ delete_partition(bdev->bd_disk, partno);
+ mutex_unlock(&bdev->bd_mutex);
+
+ ret = 0;
+out_unlock:
+ mutex_unlock(&bdevp->bd_mutex);
+ bdput(bdevp);
+ return ret;
+}
+
+int bdev_resize_partition(struct block_device *bdev, int partno,
+ sector_t start, sector_t length)
+{
+ struct block_device *bdevp;
+ struct hd_struct *part;
+ int ret = 0;
+
+ part = disk_get_part(bdev->bd_disk, partno);
+ if (!part)
+ return -ENXIO;
+
+ ret = -ENOMEM;
+ bdevp = bdget(part_devt(part));
+ if (!bdevp)
+ goto out_put_part;
+
+ mutex_lock(&bdevp->bd_mutex);
+ mutex_lock_nested(&bdev->bd_mutex, 1);
+
+ ret = -EINVAL;
+ if (start != part->start_sect)
+ goto out_unlock;
+
+ ret = -EBUSY;
+ if (partition_overlaps(bdev->bd_disk, start, length, partno))
+ goto out_unlock;
+
+ part_nr_sects_write(part, (sector_t)length);
+ i_size_write(bdevp->bd_inode, length << SECTOR_SHIFT);
+
+ ret = 0;
+out_unlock:
+ mutex_unlock(&bdevp->bd_mutex);
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(bdevp);
+out_put_part:
+ disk_put_part(part);
+ return ret;
+}
+
static bool disk_unlock_native_capacity(struct gendisk *disk)
{
const struct block_device_operations *bdops = disk->fops;
--
2.25.1