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* [PATCH] block: check disk exist before trying to add partition
@ 2021-06-08  9:27 Yufen Yu
  2021-06-08 10:08 ` Jan Kara
                   ` (3 more replies)
  0 siblings, 4 replies; 6+ messages in thread
From: Yufen Yu @ 2021-06-08  9:27 UTC (permalink / raw)
  To: axboe; +Cc: linux-block, jack, hare, ming.lei, damien.lemoal

If disk have been deleted, we should return fail for ioctl
BLKPG_DEL_PARTITION. Otherwise, the directory /sys/class/block
may remain invalid symlinks file. The race as following:

blkdev_open
				del_gendisk
				    disk->flags &= ~GENHD_FL_UP;
				    blk_drop_partitions
blkpg_ioctl
    bdev_add_partition
    add_partition
        device_add
	    device_add_class_symlinks

ioctl may add_partition after del_gendisk() have tried to delete
partitions. Then, symlinks file will be created.

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
---
 block/partitions/core.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index dc60ecf46fe6..58662a0f48e4 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -449,17 +449,26 @@ int bdev_add_partition(struct block_device *bdev, int partno,
 		sector_t start, sector_t length)
 {
 	struct block_device *part;
+	struct gendisk *disk = bdev->bd_disk;
+	int ret;
 
 	mutex_lock(&bdev->bd_mutex);
-	if (partition_overlaps(bdev->bd_disk, start, length, -1)) {
-		mutex_unlock(&bdev->bd_mutex);
-		return -EBUSY;
+	if (!(disk->flags & GENHD_FL_UP)) {
+		ret = -ENXIO;
+		goto out;
 	}
 
-	part = add_partition(bdev->bd_disk, partno, start, length,
+	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(&bdev->bd_mutex);
-	return PTR_ERR_OR_ZERO(part);
+	return ret;
 }
 
 int bdev_del_partition(struct block_device *bdev, int partno)
-- 
2.25.4


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] block: check disk exist before trying to add partition
  2021-06-08  9:27 [PATCH] block: check disk exist before trying to add partition Yufen Yu
@ 2021-06-08 10:08 ` Jan Kara
  2021-06-08 17:10 ` Christoph Hellwig
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 6+ messages in thread
From: Jan Kara @ 2021-06-08 10:08 UTC (permalink / raw)
  To: Yufen Yu; +Cc: axboe, linux-block, jack, hare, ming.lei, damien.lemoal

On Tue 08-06-21 17:27:07, Yufen Yu wrote:
> If disk have been deleted, we should return fail for ioctl
> BLKPG_DEL_PARTITION. Otherwise, the directory /sys/class/block
> may remain invalid symlinks file. The race as following:
> 
> blkdev_open
> 				del_gendisk
> 				    disk->flags &= ~GENHD_FL_UP;
> 				    blk_drop_partitions
> blkpg_ioctl
>     bdev_add_partition
>     add_partition
>         device_add
> 	    device_add_class_symlinks
> 
> ioctl may add_partition after del_gendisk() have tried to delete
> partitions. Then, symlinks file will be created.
> 
> Signed-off-by: Yufen Yu <yuyufen@huawei.com>

Looks good to me. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  block/partitions/core.c | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/block/partitions/core.c b/block/partitions/core.c
> index dc60ecf46fe6..58662a0f48e4 100644
> --- a/block/partitions/core.c
> +++ b/block/partitions/core.c
> @@ -449,17 +449,26 @@ int bdev_add_partition(struct block_device *bdev, int partno,
>  		sector_t start, sector_t length)
>  {
>  	struct block_device *part;
> +	struct gendisk *disk = bdev->bd_disk;
> +	int ret;
>  
>  	mutex_lock(&bdev->bd_mutex);
> -	if (partition_overlaps(bdev->bd_disk, start, length, -1)) {
> -		mutex_unlock(&bdev->bd_mutex);
> -		return -EBUSY;
> +	if (!(disk->flags & GENHD_FL_UP)) {
> +		ret = -ENXIO;
> +		goto out;
>  	}
>  
> -	part = add_partition(bdev->bd_disk, partno, start, length,
> +	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(&bdev->bd_mutex);
> -	return PTR_ERR_OR_ZERO(part);
> +	return ret;
>  }
>  
>  int bdev_del_partition(struct block_device *bdev, int partno)
> -- 
> 2.25.4
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] block: check disk exist before trying to add partition
  2021-06-08  9:27 [PATCH] block: check disk exist before trying to add partition Yufen Yu
  2021-06-08 10:08 ` Jan Kara
@ 2021-06-08 17:10 ` Christoph Hellwig
  2021-06-08 21:08 ` Jens Axboe
  2021-06-10  6:28 ` Ming Lei
  3 siblings, 0 replies; 6+ messages in thread
From: Christoph Hellwig @ 2021-06-08 17:10 UTC (permalink / raw)
  To: Yufen Yu; +Cc: axboe, linux-block, jack, hare, ming.lei, damien.lemoal

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] block: check disk exist before trying to add partition
  2021-06-08  9:27 [PATCH] block: check disk exist before trying to add partition Yufen Yu
  2021-06-08 10:08 ` Jan Kara
  2021-06-08 17:10 ` Christoph Hellwig
@ 2021-06-08 21:08 ` Jens Axboe
  2021-06-10  2:30   ` Yufen Yu
  2021-06-10  6:28 ` Ming Lei
  3 siblings, 1 reply; 6+ messages in thread
From: Jens Axboe @ 2021-06-08 21:08 UTC (permalink / raw)
  To: Yufen Yu; +Cc: linux-block, jack, hare, ming.lei, damien.lemoal

On 6/8/21 3:27 AM, Yufen Yu wrote:
> If disk have been deleted, we should return fail for ioctl
> BLKPG_DEL_PARTITION. Otherwise, the directory /sys/class/block
> may remain invalid symlinks file. The race as following:
> 
> blkdev_open
> 				del_gendisk
> 				    disk->flags &= ~GENHD_FL_UP;
> 				    blk_drop_partitions
> blkpg_ioctl
>     bdev_add_partition
>     add_partition
>         device_add
> 	    device_add_class_symlinks
> 
> ioctl may add_partition after del_gendisk() have tried to delete
> partitions. Then, symlinks file will be created.

Let's do this for 5.14, which means send it against for-5.14/block
please. Thanks.

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] block: check disk exist before trying to add partition
  2021-06-08 21:08 ` Jens Axboe
@ 2021-06-10  2:30   ` Yufen Yu
  0 siblings, 0 replies; 6+ messages in thread
From: Yufen Yu @ 2021-06-10  2:30 UTC (permalink / raw)
  To: Jens Axboe; +Cc: linux-block, jack, hare, ming.lei, damien.lemoal



On 2021/6/9 5:08, Jens Axboe wrote:
> On 6/8/21 3:27 AM, Yufen Yu wrote:
>> If disk have been deleted, we should return fail for ioctl
>> BLKPG_DEL_PARTITION. Otherwise, the directory /sys/class/block
>> may remain invalid symlinks file. The race as following:
>>
>> blkdev_open
>> 				del_gendisk
>> 				    disk->flags &= ~GENHD_FL_UP;
>> 				    blk_drop_partitions
>> blkpg_ioctl
>>      bdev_add_partition
>>      add_partition
>>          device_add
>> 	    device_add_class_symlinks
>>
>> ioctl may add_partition after del_gendisk() have tried to delete
>> partitions. Then, symlinks file will be created.
> 
> Let's do this for 5.14, which means send it against for-5.14/block
> please. Thanks.
> 

OK, I have send v2 for 5.14/block.
https://lore.kernel.org/linux-block/20210610023241.3646241-1-yuyufen@huawei.com/T/#u

Thanks,
Yufen

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] block: check disk exist before trying to add partition
  2021-06-08  9:27 [PATCH] block: check disk exist before trying to add partition Yufen Yu
                   ` (2 preceding siblings ...)
  2021-06-08 21:08 ` Jens Axboe
@ 2021-06-10  6:28 ` Ming Lei
  3 siblings, 0 replies; 6+ messages in thread
From: Ming Lei @ 2021-06-10  6:28 UTC (permalink / raw)
  To: Yufen Yu; +Cc: Jens Axboe, linux-block, jack, Hannes Reinecke, damien.lemoal

On Tue, Jun 8, 2021 at 5:21 PM Yufen Yu <yuyufen@huawei.com> wrote:
>
> If disk have been deleted, we should return fail for ioctl
> BLKPG_DEL_PARTITION. Otherwise, the directory /sys/class/block
> may remain invalid symlinks file. The race as following:
>
> blkdev_open
>                                 del_gendisk
>                                     disk->flags &= ~GENHD_FL_UP;
>                                     blk_drop_partitions
> blkpg_ioctl
>     bdev_add_partition
>     add_partition
>         device_add
>             device_add_class_symlinks
>
> ioctl may add_partition after del_gendisk() have tried to delete
> partitions. Then, symlinks file will be created.
>
> Signed-off-by: Yufen Yu <yuyufen@huawei.com>

Reviewed-by: Ming Lei <ming.lei@redhat.com>

-- 
Ming


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-06-10  6:28 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-08  9:27 [PATCH] block: check disk exist before trying to add partition Yufen Yu
2021-06-08 10:08 ` Jan Kara
2021-06-08 17:10 ` Christoph Hellwig
2021-06-08 21:08 ` Jens Axboe
2021-06-10  2:30   ` Yufen Yu
2021-06-10  6:28 ` Ming Lei

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