From: Christian Brauner <brauner@xxxxxxxxxx> BLKPG_DEL_PARTITION refuses to delete partitions that still have openers, i.e., that has an elevated @bdev->bd_openers count. If a device is claimed by setting @bdev->bd_holder and @bdev->bd_holder_ops @bdev->bd_openers and @bdev->bd_holders are incremented. @bdev->bd_openers is effectively guaranteed to be >= @bdev->bd_holders. So as long as @bdev->bd_openers isn't zero we know that this partition is still in active use and that there might still be @bdev->bd_holder and @bdev->bd_holder_ops set. The only current example is @fs_holder_ops for filesystems. But that means bdev_mark_dead() which calls into bdev->bd_holder_ops->mark_dead::fs_bdev_mark_dead() is a nop. As long as there's an elevated @bdev->bd_openers count we can't delete the partition and if there isn't an elevated @bdev->bd_openers count then there's no @bdev->bd_holder or @bdev->bd_holder_ops. So simply open-code what we need to do. This gets rid of one more instance where we acquire s_umount under @disk->open_mutex. Link: https://lore.kernel.org/r/20231016-fototermin-umriss-59f1ea6c1fe6@brauner Reviewed-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Reviewed-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx> Signed-off-by: Christoph Hellwig <hch@xxxxxx> --- block/partitions/core.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/block/partitions/core.c b/block/partitions/core.c index e137a87f4db0d3..b0585536b407a5 100644 --- a/block/partitions/core.c +++ b/block/partitions/core.c @@ -485,7 +485,18 @@ int bdev_del_partition(struct gendisk *disk, int partno) if (atomic_read(&part->bd_openers)) goto out_unlock; - delete_partition(part); + /* + * 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); -- 2.39.2
