On Thu, Jan 26, 2017 at 5:17 AM, Christoph Hellwig <h...@lst.de> wrote: > 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.
I came to a similar conclusion here: https://marc.info/?l=linux-scsi&m=147103737421897&w=4 James had some concerns, but I think its now clear this problem is bigger than something we can fix locally in scsi.
