lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <69a7c037-6b4b-dbe3-2b42-77f85043b9eb@nvidia.com> Date: Wed, 4 Sep 2019 16:12:35 -0700 From: John Hubbard <jhubbard@...dia.com> To: <ira.weiny@...el.com>, Andrew Morton <akpm@...ux-foundation.org> CC: Jason Gunthorpe <jgg@...pe.ca>, Dan Williams <dan.j.williams@...el.com>, Matthew Wilcox <willy@...radead.org>, Jan Kara <jack@...e.cz>, Theodore Ts'o <tytso@....edu>, Michal Hocko <mhocko@...e.com>, Dave Chinner <david@...morbit.com>, <linux-xfs@...r.kernel.org>, <linux-rdma@...r.kernel.org>, <linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>, <linux-nvdimm@...ts.01.org>, <linux-ext4@...r.kernel.org>, <linux-mm@...ck.org> Subject: Re: [RFC PATCH v2 02/19] fs/locks: Add Exclusive flag to user Layout lease On 8/9/19 3:58 PM, ira.weiny@...el.com wrote: > From: Ira Weiny <ira.weiny@...el.com> > > Add an exclusive lease flag which indicates that the layout mechanism > can not be broken. After studying the rest of these discussions extensively, I think in all cases FL_EXCLUSIVE is better named "unbreakable", rather than exclusive. If you read your sentence above, it basically reinforces that idea: "add an exclusive flag to mean it is unbreakable" is a bit of a disconnect. It would be better to say, Add an "unbreakable" lease flag which indicates that the layout lease cannot be broken. Furthermore, while this may or may not be a way forward on the "we cannot have more than one process take a layout lease on a file/range", it at least stops making it impossible. In other words, no one is going to write a patch that allows sharing an exclusive layout lease--but someone might well update some of these patches here to make it possible to have multiple processes take unbreakable leases on the same file/range. I haven't worked through everything there yet, but again: * FL_UNBREAKABLE is the name you're looking for here, and * I think we want to allow multiple processes to take FL_UNBREAKABLE leases on the same file/range, so that we can make RDMA setups reasonable. By "reasonable" I mean, "no need to have a lead process that owns all the leases". thanks, -- John Hubbard NVIDIA
Powered by blists - more mailing lists