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: <1075373.1703004999@warthog.procyon.org.uk> Date: Tue, 19 Dec 2023 16:56:39 +0000 From: David Howells <dhowells@...hat.com> To: Jeff Layton <jlayton@...nel.org> Cc: dhowells@...hat.com, Steve French <smfrench@...il.com>, Matthew Wilcox <willy@...radead.org>, Marc Dionne <marc.dionne@...istor.com>, Paulo Alcantara <pc@...guebit.com>, Shyam Prasad N <sprasad@...rosoft.com>, Tom Talpey <tom@...pey.com>, Dominique Martinet <asmadeus@...ewreck.org>, Eric Van Hensbergen <ericvh@...nel.org>, Ilya Dryomov <idryomov@...il.com>, Christian Brauner <christian@...uner.io>, linux-cachefs@...hat.com, linux-afs@...ts.infradead.org, linux-cifs@...r.kernel.org, linux-nfs@...r.kernel.org, ceph-devel@...r.kernel.org, v9fs@...ts.linux.dev, linux-fsdevel@...r.kernel.org, linux-mm@...ck.org, netdev@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v4 37/39] netfs: Optimise away reads above the point at which there can be no data Jeff Layton <jlayton@...nel.org> wrote: > > (4) On local truncation up, we don't change zero_point. > > > > The above seems odd, but I guess the assumption is that if there are any > writes by a 3rd party above the old zero point, that that would cause an > invalidation? All truncating up does is extend the region from which reading would return zeros, so it doesn't affect the zero_point. If a third party interferes, then we have to invalidate the local caches and reset zero_point to the EOF. But if a third party is writing to the file at the same time as you without both of you using locking or exclusive direct writes, your data is probably screwed anyway... Something cifs and ceph can use leasing to make this work; afs uses the data version number, notifications and the principle that you should use file locks. David
Powered by blists - more mailing lists