(no subject)

[Christoph Hellwig]

Subject: more partition handling cleanups

Hi Jens,

this series cleans up more lose ends in the partitioning code.  It also
removes a rather annoying use of ioctl_by_bdev in the s390 dasd driver.

[PATCH 01/10] block: refactor blkpg_ioctl

[Christoph Hellwig]

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..3de5b29c839e 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_DEL_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 1a0a829d8416..7577bdba3b2b 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

Re: [PATCH 01/10] block: refactor blkpg_ioctl

[Johannes Thumshirn]

On 08/04/2020 21:45, Christoph Hellwig wrote:
> +	case BLKPG_DEL_PARTITION:
> +		return bdev_resize_partition(bdev, p.pno, start, length);

This needs to be BLKPG_RESIZE_PARTITION.

[PATCH 02/10] block: pass a hd_struct to delete_partition

[Christoph Hellwig]

All callers have the hd_strut at hand, so pass it instead of doing
another lookup.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk.h             |  2 +-
 block/genhd.c           |  2 +-
 block/partitions/core.c | 22 ++++++++--------------
 3 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/block/blk.h b/block/blk.h
index 305e0ac22bf7..0cbf64108922 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -390,7 +390,7 @@ char *disk_name(struct gendisk *hd, int partno, char *buf);
 #define ADDPART_FLAG_RAID	1
 #define ADDPART_FLAG_WHOLEDISK	2
 void __delete_partition(struct percpu_ref *ref);
-void delete_partition(struct gendisk *disk, int partno);
+void delete_partition(struct gendisk *disk, struct hd_struct *part);
 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);
diff --git a/block/genhd.c b/block/genhd.c
index 06b642b23a07..1cc50ad5b191 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -897,7 +897,7 @@ void del_gendisk(struct gendisk *disk)
 	while ((part = disk_part_iter_next(&piter))) {
 		invalidate_partition(disk, part->partno);
 		bdev_unhash_inode(part_devt(part));
-		delete_partition(disk, part->partno);
+		delete_partition(disk, part);
 	}
 	disk_part_iter_exit(&piter);
 
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 7577bdba3b2b..0b1b67f50652 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -296,20 +296,12 @@ void __delete_partition(struct percpu_ref *ref)
  * 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)
+void delete_partition(struct gendisk *disk, struct hd_struct *part)
 {
 	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->part[part->partno], NULL);
 	rcu_assign_pointer(ptbl->last_lookup, NULL);
 	kobject_put(part->holder_dir);
 	device_del(part_to_dev(part));
@@ -520,10 +512,10 @@ int bdev_del_partition(struct block_device *bdev, int partno)
 	if (!part)
 		return -ENXIO;
 
+	ret = -ENOMEM;
 	bdevp = bdget(part_devt(part));
-	disk_put_part(part);
 	if (!bdevp)
-		return -ENOMEM;
+		goto out_put_part;
 
 	mutex_lock(&bdevp->bd_mutex);
 
@@ -535,13 +527,15 @@ int bdev_del_partition(struct block_device *bdev, int partno)
 	invalidate_bdev(bdevp);
 
 	mutex_lock_nested(&bdev->bd_mutex, 1);
-	delete_partition(bdev->bd_disk, partno);
+	delete_partition(bdev->bd_disk, part);
 	mutex_unlock(&bdev->bd_mutex);
 
 	ret = 0;
 out_unlock:
 	mutex_unlock(&bdevp->bd_mutex);
 	bdput(bdevp);
+out_put_part:
+	disk_put_part(part);
 	return ret;
 }
 
@@ -617,7 +611,7 @@ int blk_drop_partitions(struct gendisk *disk, struct block_device *bdev)
 
 	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter)))
-		delete_partition(disk, part->partno);
+		delete_partition(disk, part);
 	disk_part_iter_exit(&piter);
 
 	return 0;
-- 
2.25.1

Re: [PATCH 02/10] block: pass a hd_struct to delete_partition

[Johannes Thumshirn]

Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Re: [PATCH 02/10] block: pass a hd_struct to delete_partition

[Johannes Thumshirn]

On 08/04/2020 21:45, Christoph Hellwig wrote:
> All callers have the hd_strut at hand, so pass it instead of doing
Nit: hd_struct

[PATCH 03/10] block: cleanup hd_struct freeing

[Christoph Hellwig]

Move hd_ref_init out of line as there it isn't anywhere near a fast path,
and rename the rcu ref freeing callbacks to be more descriptive.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk.h             | 10 +---------
 block/partitions/core.c | 18 +++++++++++++-----
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/block/blk.h b/block/blk.h
index 0cbf64108922..b1a0b8cd87f0 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -389,7 +389,6 @@ 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
-void __delete_partition(struct percpu_ref *ref);
 void delete_partition(struct gendisk *disk, struct hd_struct *part);
 int bdev_add_partition(struct block_device *bdev, int partno,
 		sector_t start, sector_t length);
@@ -397,14 +396,7 @@ 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)
-{
-	if (percpu_ref_init(&part->ref, __delete_partition, 0,
-				GFP_KERNEL))
-		return -ENOMEM;
-	return 0;
-}
+int hd_ref_init(struct hd_struct *part);
 
 static inline void hd_struct_get(struct hd_struct *part)
 {
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 0b1b67f50652..13d61ed76e0e 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -274,10 +274,10 @@ struct device_type part_type = {
 	.uevent		= part_uevent,
 };
 
-static void delete_partition_work_fn(struct work_struct *work)
+static void hd_struct_free_work(struct work_struct *work)
 {
-	struct hd_struct *part = container_of(to_rcu_work(work), struct hd_struct,
-					rcu_work);
+	struct hd_struct *part =
+		container_of(to_rcu_work(work), struct hd_struct, rcu_work);
 
 	part->start_sect = 0;
 	part->nr_sects = 0;
@@ -285,13 +285,21 @@ static void delete_partition_work_fn(struct work_struct *work)
 	put_device(part_to_dev(part));
 }
 
-void __delete_partition(struct percpu_ref *ref)
+static void hd_struct_free(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);
+
+	INIT_RCU_WORK(&part->rcu_work, hd_struct_free_work);
 	queue_rcu_work(system_wq, &part->rcu_work);
 }
 
+int hd_ref_init(struct hd_struct *part)
+{
+	if (percpu_ref_init(&part->ref, hd_struct_free, 0, GFP_KERNEL))
+		return -ENOMEM;
+	return 0;
+}
+
 /*
  * Must be called either with bd_mutex held, before a disk can be opened or
  * after all disk users are gone.
-- 
2.25.1

Re: [PATCH 03/10] block: cleanup hd_struct freeing

[Johannes Thumshirn]

On 08/04/2020 21:45, Christoph Hellwig wrote:
> -	struct hd_struct *part = container_of(to_rcu_work(work), struct hd_struct,
> -					rcu_work);
> +	struct hd_struct *part =
> +		container_of(to_rcu_work(work), struct hd_struct, rcu_work);

That looks like an unneeded white space only change

Otherwise,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Re: [PATCH 03/10] block: cleanup hd_struct freeing

[Christoph Hellwig]

On Thu, Apr 09, 2020 at 11:30:19AM +0000, Johannes Thumshirn wrote:
> On 08/04/2020 21:45, Christoph Hellwig wrote:
> > -	struct hd_struct *part = container_of(to_rcu_work(work), struct hd_struct,
> > -					rcu_work);
> > +	struct hd_struct *part =
> > +		container_of(to_rcu_work(work), struct hd_struct, rcu_work);
> 
> That looks like an unneeded white space only change

It was intentional as I was touching the code right next to it anyway..

[PATCH 04/10] block: remove hd_struct_kill

[Christoph Hellwig]

The function has a single caller, so just open code it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk.h             | 5 -----
 block/partitions/core.c | 2 +-
 2 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/block/blk.h b/block/blk.h
index b1a0b8cd87f0..204963bb03e8 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -413,11 +413,6 @@ static inline void hd_struct_put(struct hd_struct *part)
 	percpu_ref_put(&part->ref);
 }
 
-static inline void hd_struct_kill(struct hd_struct *part)
-{
-	percpu_ref_kill(&part->ref);
-}
-
 static inline void hd_free_part(struct hd_struct *part)
 {
 	free_part_stats(part);
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 13d61ed76e0e..f10968b601be 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -321,7 +321,7 @@ void delete_partition(struct gendisk *disk, struct hd_struct *part)
 	 * "in-use" until we really free the gendisk.
 	 */
 	blk_invalidate_devt(part_devt(part));
-	hd_struct_kill(part);
+	percpu_ref_kill(&part->ref);
 }
 
 static ssize_t whole_disk_show(struct device *dev,
-- 
2.25.1

Re: [PATCH 04/10] block: remove hd_struct_kill

[Johannes Thumshirn]

Easy enough,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

[PATCH 05/10] block: remove the disk argument from blk_drop_partitions

[Christoph Hellwig]

The gendisk can be trivially deducted from the block_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/partitions/core.c | 10 +++++-----
 fs/block_dev.c          |  2 +-
 include/linux/genhd.h   |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index f10968b601be..e0ff8a49279f 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -603,23 +603,23 @@ static bool disk_unlock_native_capacity(struct gendisk *disk)
 	}
 }
 
-int blk_drop_partitions(struct gendisk *disk, struct block_device *bdev)
+int blk_drop_partitions(struct block_device *bdev)
 {
 	struct disk_part_iter piter;
 	struct hd_struct *part;
 	int res;
 
-	if (!disk_part_scan_enabled(disk))
+	if (!disk_part_scan_enabled(bdev->bd_disk))
 		return 0;
 	if (bdev->bd_part_count || bdev->bd_openers)
 		return -EBUSY;
-	res = invalidate_partition(disk, 0);
+	res = invalidate_partition(bdev->bd_disk, 0);
 	if (res)
 		return res;
 
-	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
+	disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter)))
-		delete_partition(disk, part);
+		delete_partition(bdev->bd_disk, part);
 	disk_part_iter_exit(&piter);
 
 	return 0;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 52b6f646cdbd..9c8de54fa0c9 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1517,7 +1517,7 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 	lockdep_assert_held(&bdev->bd_mutex);
 
 rescan:
-	ret = blk_drop_partitions(disk, bdev);
+	ret = blk_drop_partitions(bdev);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 9b3fffdf4011..058d895544c7 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -339,7 +339,7 @@ extern dev_t blk_lookup_devt(const char *name, int partno);
 
 int bdev_disk_changed(struct block_device *bdev, bool invalidate);
 int blk_add_partitions(struct gendisk *disk, struct block_device *bdev);
-int blk_drop_partitions(struct gendisk *disk, struct block_device *bdev);
+int blk_drop_partitions(struct block_device *bdev);
 extern void printk_all_partitions(void);
 
 extern struct gendisk *__alloc_disk_node(int minors, int node_id);
-- 
2.25.1

Re: [PATCH 05/10] block: remove the disk argument from blk_drop_partitions

[Johannes Thumshirn]

On 08/04/2020 21:45, Christoph Hellwig wrote:
> -int blk_drop_partitions(struct gendisk *disk, struct block_device *bdev)
> +int blk_drop_partitions(struct block_device *bdev)
>   {
>   	struct disk_part_iter piter;
>   	struct hd_struct *part;
>   	int res;
>   
> -	if (!disk_part_scan_enabled(disk))
> +	if (!disk_part_scan_enabled(bdev->bd_disk))
>   		return 0;
>   	if (bdev->bd_part_count || bdev->bd_openers)
>   		return -EBUSY;
> -	res = invalidate_partition(disk, 0);
> +	res = invalidate_partition(bdev->bd_disk, 0);
>   	if (res)
>   		return res;
>   
> -	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
> +	disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY);
>   	while ((part = disk_part_iter_next(&piter)))
> -		delete_partition(disk, part);
> +		delete_partition(bdev->bd_disk, part);
>   	disk_part_iter_exit(&piter);

I would have probably added a local 'struct gendisk *disk' variable, but 
that's personal preference I guess.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

[PATCH 06/10] dasd: use blk_drop_partitions instead of badly reimplementing it

[Christoph Hellwig]

Use the blk_drop_partitions function instead of messing around with
ioctls that get kernel pointers.  For this blk_drop_partitions needs
to be exported, which it normally shouldn't - make an exception for
s390 only.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/partitions/core.c         |  4 ++++
 drivers/s390/block/dasd_genhd.c | 20 ++++----------------
 2 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index e0ff8a49279f..8a41c25022ab 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -624,6 +624,10 @@ int blk_drop_partitions(struct block_device *bdev)
 
 	return 0;
 }
+#ifdef CONFIG_S390
+/* for historic reasons in the DASD driver */
+EXPORT_SYMBOL_GPL(blk_drop_partitions);
+#endif
 
 static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
 		struct parsed_partitions *state, int p)
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 7d079154f849..af5b0ecb8f89 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -143,9 +143,6 @@ int dasd_scan_partitions(struct dasd_block *block)
  */
 void dasd_destroy_partitions(struct dasd_block *block)
 {
-	/* The two structs have 168/176 byte on 31/64 bit. */
-	struct blkpg_partition bpart;
-	struct blkpg_ioctl_arg barg;
 	struct block_device *bdev;
 
 	/*
@@ -155,19 +152,10 @@ void dasd_destroy_partitions(struct dasd_block *block)
 	bdev = block->bdev;
 	block->bdev = NULL;
 
-	/*
-	 * See fs/partition/check.c:delete_partition
-	 * Can't call delete_partitions directly. Use ioctl.
-	 * The ioctl also does locking and invalidation.
-	 */
-	memset(&bpart, 0, sizeof(struct blkpg_partition));
-	memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
-	barg.data = (void __force __user *) &bpart;
-	barg.op = BLKPG_DEL_PARTITION;
-	for (bpart.pno = block->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
-		ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
-
-	invalidate_partition(block->gdp, 0);
+	mutex_lock(&bdev->bd_mutex);
+	blk_drop_partitions(bdev);
+	mutex_unlock(&bdev->bd_mutex);
+
 	/* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
 	blkdev_put(bdev, FMODE_READ);
 	set_capacity(block->gdp, 0);
-- 
2.25.1

[PATCH 07/10] block: don't call invalidate_partition from blk_drop_partitions

[Christoph Hellwig]

Given that the device must not be busy, most of the calls from
invalidate_partition that are related to file system metadata are
guranteed to not happen.  Just open code the calls to sync_blockdev
and invalidate_bdev instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/partitions/core.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index 8a41c25022ab..3fe383adb42a 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -607,15 +607,14 @@ int blk_drop_partitions(struct block_device *bdev)
 {
 	struct disk_part_iter piter;
 	struct hd_struct *part;
-	int res;
 
 	if (!disk_part_scan_enabled(bdev->bd_disk))
 		return 0;
 	if (bdev->bd_part_count || bdev->bd_openers)
 		return -EBUSY;
-	res = invalidate_partition(bdev->bd_disk, 0);
-	if (res)
-		return res;
+
+	sync_blockdev(bdev);
+	invalidate_bdev(bdev);
 
 	disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY);
 	while ((part = disk_part_iter_next(&piter)))
-- 
2.25.1

[PATCH 08/10] block: simplify block device syncing in bdev_del_partition

[Christoph Hellwig]

We just checked a little above that the block device for the partition
im busy.  That implies no file system is mounted, and thus the only
thing in fsync_bdev that actually is used is sync_blockdev.  Just call
sync_blockdev directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/partitions/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index 3fe383adb42a..9c402edee4a4 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -531,7 +531,7 @@ int bdev_del_partition(struct block_device *bdev, int partno)
 	if (bdevp->bd_openers)
 		goto out_unlock;
 
-	fsync_bdev(bdevp);
+	sync_blockdev(bdevp);
 	invalidate_bdev(bdevp);
 
 	mutex_lock_nested(&bdev->bd_mutex, 1);
-- 
2.25.1

Re: [PATCH 08/10] block: simplify block device syncing in bdev_del_partition

[Johannes Thumshirn]

Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

[PATCH 09/10] block: mark invalidate_partition static

[Christoph Hellwig]

invalidate_partition is only used in genhd.c, so mark it static.  Also
drop the return value given that is is always ignored.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c      | 27 +++++++++++++--------------
 include/linux/fs.h |  1 -
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 1cc50ad5b191..980a4609d4a5 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -878,6 +878,19 @@ void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk)
 }
 EXPORT_SYMBOL(device_add_disk_no_queue_reg);
 
+static void invalidate_partition(struct gendisk *disk, int partno)
+{
+	struct block_device *bdev;
+
+	bdev = bdget_disk(disk, partno);
+	if (!bdev)
+		return;
+
+	fsync_bdev(bdev);
+	__invalidate_device(bdev, true);
+	bdput(bdev);
+}
+
 void del_gendisk(struct gendisk *disk)
 {
 	struct disk_part_iter piter;
@@ -1806,20 +1819,6 @@ int bdev_read_only(struct block_device *bdev)
 
 EXPORT_SYMBOL(bdev_read_only);
 
-int invalidate_partition(struct gendisk *disk, int partno)
-{
-	int res = 0;
-	struct block_device *bdev = bdget_disk(disk, partno);
-	if (bdev) {
-		fsync_bdev(bdev);
-		res = __invalidate_device(bdev, true);
-		bdput(bdev);
-	}
-	return res;
-}
-
-EXPORT_SYMBOL(invalidate_partition);
-
 /*
  * Disk events - monitor disk events like media change and eject request.
  */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4f6f59b4f22a..2b4e9f86b151 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2723,7 +2723,6 @@ extern bool is_bad_inode(struct inode *);
 extern int revalidate_disk(struct gendisk *);
 extern int check_disk_change(struct block_device *);
 extern int __invalidate_device(struct block_device *, bool);
-extern int invalidate_partition(struct gendisk *, int);
 #endif
 unsigned long invalidate_mapping_pages(struct address_space *mapping,
 					pgoff_t start, pgoff_t end);
-- 
2.25.1

Re: [PATCH 09/10] block: mark invalidate_partition static

[Johannes Thumshirn]

Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

[PATCH 10/10] block: fold bdev_unhash_inode into invalidate_partition

[Christoph Hellwig]

invalidate_partition and bdev_unhash_inode are always paired, and
invalidate_partition already does an icache lookup for the block device
inode.  Piggy back on that to remove the inode from the hash.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c      |  8 ++++++--
 fs/block_dev.c     | 15 ---------------
 include/linux/fs.h |  1 -
 3 files changed, 6 insertions(+), 18 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 980a4609d4a5..c05d509877fa 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -888,6 +888,12 @@ static void invalidate_partition(struct gendisk *disk, int partno)
 
 	fsync_bdev(bdev);
 	__invalidate_device(bdev, true);
+
+	/*
+	 * Unhash the bdev inode for this device so that it gets evicted as soon
+	 * as last inode reference is dropped.
+	 */
+	remove_inode_hash(bdev->bd_inode);
 	bdput(bdev);
 }
 
@@ -909,13 +915,11 @@ void del_gendisk(struct gendisk *disk)
 			     DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
 	while ((part = disk_part_iter_next(&piter))) {
 		invalidate_partition(disk, part->partno);
-		bdev_unhash_inode(part_devt(part));
 		delete_partition(disk, part);
 	}
 	disk_part_iter_exit(&piter);
 
 	invalidate_partition(disk, 0);
-	bdev_unhash_inode(disk_devt(disk));
 	set_capacity(disk, 0);
 	disk->flags &= ~GENHD_FL_UP;
 	up_write(&disk->lookup_sem);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9c8de54fa0c9..998820174d3e 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -883,21 +883,6 @@ static int bdev_set(struct inode *inode, void *data)
 
 static LIST_HEAD(all_bdevs);
 
-/*
- * If there is a bdev inode for this device, unhash it so that it gets evicted
- * as soon as last inode reference is dropped.
- */
-void bdev_unhash_inode(dev_t dev)
-{
-	struct inode *inode;
-
-	inode = ilookup5(blockdev_superblock, hash(dev), bdev_test, &dev);
-	if (inode) {
-		remove_inode_hash(inode);
-		iput(inode);
-	}
-}
-
 struct block_device *bdget(dev_t dev)
 {
 	struct block_device *bdev;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2b4e9f86b151..1a95e5158811 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2581,7 +2581,6 @@ extern struct kmem_cache *names_cachep;
 #ifdef CONFIG_BLOCK
 extern int register_blkdev(unsigned int, const char *);
 extern void unregister_blkdev(unsigned int, const char *);
-extern void bdev_unhash_inode(dev_t dev);
 extern struct block_device *bdget(dev_t);
 extern struct block_device *bdgrab(struct block_device *bdev);
 extern void bd_set_size(struct block_device *, loff_t size);
-- 
2.25.1

Re: [PATCH 10/10] block: fold bdev_unhash_inode into invalidate_partition

[Johannes Thumshirn]

Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

more partition handling cleanups v2

[Christoph Hellwig]

Hi Jens,

this series cleans up more lose ends in the partitioning code.  It also
removes a rather annoying use of ioctl_by_bdev in the s390 dasd driver.

Changes since v1:
 - fix a brown paperbag typo in blkpg_do_ioctl
 - fix a commit message typo

[PATCH 06/10] dasd: use blk_drop_partitions instead of badly reimplementing it

[Christoph Hellwig]

Use the blk_drop_partitions function instead of messing around with
ioctls that get kernel pointers.  For this blk_drop_partitions needs
to be exported, which it normally shouldn't - make an exception for
s390 only.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/partitions/core.c         |  4 ++++
 drivers/s390/block/dasd_genhd.c | 20 ++++----------------
 2 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index deccc3fbcd37..8c5295ca8ea6 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -624,6 +624,10 @@ int blk_drop_partitions(struct block_device *bdev)
 
 	return 0;
 }
+#ifdef CONFIG_S390
+/* for historic reasons in the DASD driver */
+EXPORT_SYMBOL_GPL(blk_drop_partitions);
+#endif
 
 static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
 		struct parsed_partitions *state, int p)
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 7d079154f849..af5b0ecb8f89 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -143,9 +143,6 @@ int dasd_scan_partitions(struct dasd_block *block)
  */
 void dasd_destroy_partitions(struct dasd_block *block)
 {
-	/* The two structs have 168/176 byte on 31/64 bit. */
-	struct blkpg_partition bpart;
-	struct blkpg_ioctl_arg barg;
 	struct block_device *bdev;
 
 	/*
@@ -155,19 +152,10 @@ void dasd_destroy_partitions(struct dasd_block *block)
 	bdev = block->bdev;
 	block->bdev = NULL;
 
-	/*
-	 * See fs/partition/check.c:delete_partition
-	 * Can't call delete_partitions directly. Use ioctl.
-	 * The ioctl also does locking and invalidation.
-	 */
-	memset(&bpart, 0, sizeof(struct blkpg_partition));
-	memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
-	barg.data = (void __force __user *) &bpart;
-	barg.op = BLKPG_DEL_PARTITION;
-	for (bpart.pno = block->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
-		ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
-
-	invalidate_partition(block->gdp, 0);
+	mutex_lock(&bdev->bd_mutex);
+	blk_drop_partitions(bdev);
+	mutex_unlock(&bdev->bd_mutex);
+
 	/* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
 	blkdev_put(bdev, FMODE_READ);
 	set_capacity(block->gdp, 0);
-- 
2.25.1