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b=cLDGV3zNwpX1aR8HoBDJKGt6Xmu2cUS1GvQpFKZW7r0UZBUBmYoSQZv2JYPlUkxnS 5Y2bMJBTFJ8s0Jc/cT8tPlYrpezHXoWBtIwrm03mq6i9kfsBSiZ29Xa5vC0QcOjPnd 3dFPg4wVeXIZZdMtioq3xIf3/UUBNnbNesXGDaisMHsLXi3s5ErHkpzt9ifXseP6jG zUKNlC8rVTWCCWWa8MUF9rFVPqz9rayDUBo90eNWU6lp3NowHzYHRZn/lG32fcI+EJ ANN9VU9WagM7lNJ/7RLneTw2+QjucJu2k8GCh3kfr0t3ssTqWNFsay/9EcH9chA4CW Vfgefh8qY7ssA== Date: Wed, 15 Nov 2023 21:25:51 +0100 From: Christian Brauner To: Al Viro Cc: Chuck Lever , akpm@linux-foundation.org, hughd@google.com, jlayton@redhat.com, Tavian Barnes , Chuck Lever , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH RFC] libfs: getdents() should return 0 after reaching EOD Message-ID: <20231115-formt-siedeln-45b635164d38@brauner> References: <169997697704.4588.14555611205729567800.stgit@bazille.1015granger.net> <20231114-begleichen-miniatur-3c3a02862c4c@brauner> <20231114175714.GT1957730@ZenIV> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20231114175714.GT1957730@ZenIV> X-Rspamd-Queue-Id: 0973820015 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: 75q5hdpdoao3hrh5ao16ryc1t5miwhhe X-HE-Tag: 1700079957-806170 X-HE-Meta: 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 J5wBbABb S359g0DJlcizpW13vboVBxCfD9rcJh+aYTWtftvRDy8vEz2k2g9zNNLi9PSlnLLBD0c33f+Mfb100WRFqAzawUmuLx7/xuvPDbrplHBazsayujhvlB0S+TBb7NVR05ayUq5UM3YPIvTFK4pPS0kvto44D3nOCViD6cWu38M8Mj9r6GWMrjYpjdQJi0Q== X-Bogosity: Ham, tests=bogofilter, spamicity=0.001837, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Nov 14, 2023 at 05:57:14PM +0000, Al Viro wrote: > On Tue, Nov 14, 2023 at 06:29:15PM +0100, Christian Brauner wrote: > > > I think it's usually best practice to only modify the file->private_data > > pointer during f_op->open and f_op->close but not override > > file->private_data once the file is visible to other threads. I think > > here it might not matter because access to file->private_data is > > serialized on f_pos_lock and it's not used by anything else. > > That is entirely up to filesystem. Warning that use of that library > helper means that you can't use your ->d_fsdata for anything else - sure, > but that's it. Yes, but it's usually easier to reason about if the pointer just changes during open/close. Nothing I wrote said that it's mandated just so I'm clear.