From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 14/15] libnvdimm: support read-only btt backing devices Date: Sun, 21 Jun 2015 12:13:46 +0200 Message-ID: <20150621101346.GF5915@lst.de> References: <20150617235209.12943.24419.stgit@dwillia2-desk3.amr.corp.intel.com> <20150617235602.12943.24958.stgit@dwillia2-desk3.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20150617235602.12943.24958.stgit@dwillia2-desk3.amr.corp.intel.com> Sender: linux-fsdevel-owner@vger.kernel.org To: Dan Williams Cc: axboe@kernel.dk, linux-nvdimm@lists.01.org, boaz@plexistor.com, toshi.kani@hp.com, linux-kernel@vger.kernel.org, hch@lst.de, linux-acpi@vger.kernel.org, linux-fsdevel@vger.kernel.org, mingo@kernel.org List-Id: linux-acpi@vger.kernel.org On Wed, Jun 17, 2015 at 07:56:02PM -0400, Dan Williams wrote: > Upon detection of a read-only backing device arrange for the btt to > device to be read only. Implement a catch for the BLKROSET ioctl and > only allow a btt-instance to become read-write when the backing-device > becomes read-write. Conversely, if a backing-device becomes read-only > arrange for its parent btt to be marked read-only. Synchronize these > changes under the bus lock. Eww. I have to say the deeper I look into this code the more I hate the stacking nature of btt. It seems more and more we should never attach pmem if we want to use a device with btt. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in