# Re: \[RFC PATCH v2 0/2\] block: fix backing\_dev\_info lifetime

- From: Christoph Hellwig \<hch@lst.de\>
- Date: 2017-01-26 13:17:58 
- List: linux-block
- Page: https://ratatoskr.run/linux-block/2017/01/116238
- Thread: https://ratatoskr.run/linux-block/2017/01/116242/t.md

```text
On Thu, Jan 26, 2017 at 11:06:53AM +0100, Jan Kara wrote:
> Yeah, so my patches (and I suspect your as well), have a problem when the
> backing_device_info stays around because blkdev inode still exists, device
> gets removed (e.g. USB disk gets unplugged) but blkdev inode still stays
> around (there doesn't appear to be anything that would be forcing blkdev
> inode out of cache on device removal and there cannot be because different
> processes may hold inode reference) and then some other device gets plugged
> in and reuses the same MAJOR:MINOR combination. Things get awkward there, I
> think we need to unhash blkdev inode on device removal but so far I didn't
> make this work...

The other option is to simply not release the dev_t until the backing_dev
is gone.
```