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[54.240.9.37]) by mx.google.com with ESMTPS id a2si853762qkl.123.2019.04.03.10.56.28 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 03 Apr 2019 10:56:28 -0700 (PDT) Received-SPF: pass (google.com: domain of 01000169e458534a-3c6a5d6f-3054-4c64-b5f9-7f46c811eeac-000000@amazonses.com designates 54.240.9.37 as permitted sender) client-ip=54.240.9.37; Authentication-Results: mx.google.com; dkim=pass header.i=@amazonses.com header.s=6gbrjpgwjskckoa6a5zn6fwqkn67xbtw header.b=ECT6lpn3; spf=pass (google.com: domain of 01000169e458534a-3c6a5d6f-3054-4c64-b5f9-7f46c811eeac-000000@amazonses.com designates 54.240.9.37 as permitted sender) smtp.mailfrom=01000169e458534a-3c6a5d6f-3054-4c64-b5f9-7f46c811eeac-000000@amazonses.com DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/simple; s=6gbrjpgwjskckoa6a5zn6fwqkn67xbtw; d=amazonses.com; t=1554314187; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References:MIME-Version:Content-Type:Feedback-ID; bh=Wyd/86VQr4yB+T3sAKBmvWlFZRyqyhljETAB3MKNVBw=; b=ECT6lpn36hcc5RiE9hxy2iLqLJPNP+ceZdI1xVdCLGsleGlkdonBVCwBaMVznKj4 9CTvSAAFdKBjZ5hY26du2Zk6Bwpjfzk1DQnCiRgMlrd7d6F9fC1XJwzxF8Lb0VLl5iT ZVRQU9YU3p/X/L7Wsb55owNa6j6s7KblS1qdWtJ0= Date: Wed, 3 Apr 2019 17:56:27 +0000 From: Christopher Lameter X-X-Sender: cl@nuc-kabylake To: Al Viro cc: "Tobin C. Harding" , Andrew Morton , Roman Gushchin , Alexander Viro , Christoph Hellwig , Pekka Enberg , David Rientjes , Joonsoo Kim , Matthew Wilcox , Miklos Szeredi , Andreas Dilger , Waiman Long , Tycho Andersen , Theodore Ts'o , Andi Kleen , David Chinner , Nick Piggin , Rik van Riel , Hugh Dickins , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Linus Torvalds Subject: Re: [RFC PATCH v2 14/14] dcache: Implement object migration In-Reply-To: <20190403170811.GR2217@ZenIV.linux.org.uk> Message-ID: <01000169e458534a-3c6a5d6f-3054-4c64-b5f9-7f46c811eeac-000000@email.amazonses.com> References: <20190403042127.18755-1-tobin@kernel.org> <20190403042127.18755-15-tobin@kernel.org> <20190403170811.GR2217@ZenIV.linux.org.uk> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-SES-Outgoing: 2019.04.03-54.240.9.37 Feedback-ID: 1.us-east-1.fQZZZ0Xtj2+TD7V5apTT/NrT6QKuPgzCT/IC7XYgDKI=:AmazonSES X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 3 Apr 2019, Al Viro wrote: > Let's do d_invalidate() on random dentries and hope they go away. > With convoluted and brittle logics for deciding which ones to > spare, which is actually wrong. This will pick mountpoints > and tear them out, to start with. > > NAKed-by: Al Viro > > And this is a NAK for the entire approach; if it has a positive refcount, > LEAVE IT ALONE. Period. Don't play this kind of games, they are wrong. > d_invalidate() is not something that can be done to an arbitrary dentry. Well could you help us figure out how to do it the right way? We (the MM guys) are having a hard time not being familiar with the filesystem stuff. This is an RFC and we want to know how to do this right.