From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=0.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,FSL_HELO_FAKE,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 325FDC10F11 for ; Wed, 10 Apr 2019 23:17:19 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EFF1F20820 for ; Wed, 10 Apr 2019 23:17:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="mlgLL/wB"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="OxyQkFX6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EFF1F20820 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=8RvlIsjDSVqc8LJFoQu9cjO863e7ax4NutBRBTh8eQw=; b=mlgLL/wBJGfVcu 16AHmryDd81/x3w+cT8PAaz3GONZ2jXKdcDWUFfTunY/OJJmfiGf3OoBr8ySdVBmbbxp2AatlsufV jSnKWlOfIhmJfVM8ncUgqL4vorgD2EOYxAeA0kVE8GEKFCjKcHp/sfLwZLL1Fh4n4H9bJkiw6Oyrp WAFOrnryeYNcSVVlCq/VAbhqgjbBpT8vGY08VHQrqyWKYgOr3POeQ1KUBfKVtMI5uFEHRtbvPTahB KI/9LV2mfalHof+kkaHRIpLOL6/DwIQnhLTnTLbVYHVc6+inl8FGxgwehkKV5rJNyuzMbGSSgKOnE x46YtpJIQj4ZQzh8Q4PA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hEMSv-0000oD-UL; Wed, 10 Apr 2019 23:17:13 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hEMRa-0007WI-3f for linux-mtd@lists.infradead.org; Wed, 10 Apr 2019 23:16:00 +0000 Received: from gmail.com (unknown [104.132.1.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7E03D20820; Wed, 10 Apr 2019 23:15:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554938149; bh=1gxdAOnNojCmWwSJ0r0v7Nz8pxGPPrn4uqvTyWoyzj0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OxyQkFX684C7eZmJwptSahUQ6Wbb6ZK4wZtvbcsutr0tFJjQ/W8lk55uWFGIghziA C8nWLHF5D1l4fg/KzPfKa/PAFmoGv/Mmp3WmNrsh7YmxX7JuXi0IK40U5AUltPI0oR 8+A435xGUwMS1PsigLo/PgxVTeG454qdYDNzEVhk= Date: Wed, 10 Apr 2019 16:15:48 -0700 From: Eric Biggers To: Al Viro Subject: Re: [PATCH v2 1/2] vfs: use READ_ONCE() to access ->i_link Message-ID: <20190410231547.GC120258@gmail.com> References: <20190410202115.64501-1-ebiggers@kernel.org> <20190410202115.64501-2-ebiggers@kernel.org> <20190410210657.GA2217@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190410210657.GA2217@ZenIV.linux.org.uk> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190410_161550_802866_22724BFE X-CRM114-Status: GOOD ( 12.73 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org, linux-mtd@lists.infradead.org, linux-f2fs-devel@lists.sourceforge.net Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Wed, Apr 10, 2019 at 10:06:57PM +0100, Al Viro wrote: > On Wed, Apr 10, 2019 at 01:21:14PM -0700, Eric Biggers wrote: > > From: Eric Biggers > > > > Use 'READ_ONCE(inode->i_link)' to explicitly support filesystems caching > > the symlink target in ->i_link later if it was unavailable at iget() > > time, or wasn't easily available. I'll be doing this in fscrypt, to > > improve the performance of encrypted symlinks on ext4, f2fs, and ubifs. > > > > ->i_link will start NULL and may later be set to a non-NULL value by a > > smp_store_release() or cmpxchg_release(). READ_ONCE() is needed on the > > read side. smp_load_acquire() is unnecessary because only a data > > dependency barrier is required. (Thanks to Al for pointing this out.) > > You've missed vfs_readlink()... How so? The patch already updates vfs_readlink(). - Eric ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/