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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D649C3DA42 for ; Wed, 17 Jul 2024 11:31:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 98A666B00A5; Wed, 17 Jul 2024 07:31:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 928046B00A6; Wed, 17 Jul 2024 07:31:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7F0096B00A7; Wed, 17 Jul 2024 07:31:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 60F6B6B00A5 for ; Wed, 17 Jul 2024 07:31:41 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 03A91160A42 for ; Wed, 17 Jul 2024 11:31:40 +0000 (UTC) X-FDA: 82349029602.28.131D9F6 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) by imf20.hostedemail.com (Postfix) with ESMTP id B3BE21C0029 for ; Wed, 17 Jul 2024 11:31:38 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=Rykqp0CY; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b="WQV+/WdD"; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=Rykqp0CY; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b="WQV+/WdD"; spf=pass (imf20.hostedemail.com: domain of jack@suse.cz designates 195.135.223.130 as permitted sender) smtp.mailfrom=jack@suse.cz; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1721215880; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Pw5IFteg62fADv1t8c9j1uoPtsRwzO5/xi3gHqXwEVA=; b=EzI3OvhAzmSEM7mFy7zYR0D7M3KTd+y980IH+WiJAhhN/0BG44/ZmJm3MDAa4Ssfptx9NB +rxsBbxT5mPw0BhwuTcPu6SmSWtluuQ24xVcgjc208e+WjK+MEu/nXqxaYW9a9eQNcc9n+ uvy8CAOrO9UJGu/u2UzO1hlWgl3iC8U= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=Rykqp0CY; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b="WQV+/WdD"; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=Rykqp0CY; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b="WQV+/WdD"; spf=pass (imf20.hostedemail.com: domain of jack@suse.cz designates 195.135.223.130 as permitted sender) smtp.mailfrom=jack@suse.cz; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1721215880; a=rsa-sha256; cv=none; b=fmiQo7IfXVr0c3WV+c9J8dhmKZgSm4se5vkDtTI2j2cRPhgNisToVWiJrrbYFyKYbzGZQ0 YOBPLNSV8MWTkuY6xHXailmViFByILH8uZSOuGe6Zppnt9TSRx8HtRVAJ02m4s5CwdPgQB xwx9QNM4yFRbb5n2HEYy7B6oQs2KV/U= Received: from imap1.dmz-prg2.suse.org (unknown [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 21DB321A8E; Wed, 17 Jul 2024 11:31:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1721215897; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Pw5IFteg62fADv1t8c9j1uoPtsRwzO5/xi3gHqXwEVA=; b=Rykqp0CYm0hFK3gJ1goLxjFMrOjs+3P+N+YdNngEw3rvNGXmZW5O8enAii/Et6SAyjUNz1 BBy3VCfbtg+A9r48c9EqAyKM3pt9BX6I2EtTQWQS2hQaEERp30v5EsF6mspRCNdyWJtgXH /4FnemB4Tv336YPKjbj+C68/MGnjBTk= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1721215897; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Pw5IFteg62fADv1t8c9j1uoPtsRwzO5/xi3gHqXwEVA=; b=WQV+/WdDh8I/zwwwpRq/2aYepPcMfGhbrdMTUHCYiHV9Z+sJ/Q6ftIuEgAfnhQTlaVKGFy Tq6+pHrlKiUsXNBA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1721215897; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Pw5IFteg62fADv1t8c9j1uoPtsRwzO5/xi3gHqXwEVA=; b=Rykqp0CYm0hFK3gJ1goLxjFMrOjs+3P+N+YdNngEw3rvNGXmZW5O8enAii/Et6SAyjUNz1 BBy3VCfbtg+A9r48c9EqAyKM3pt9BX6I2EtTQWQS2hQaEERp30v5EsF6mspRCNdyWJtgXH /4FnemB4Tv336YPKjbj+C68/MGnjBTk= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1721215897; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Pw5IFteg62fADv1t8c9j1uoPtsRwzO5/xi3gHqXwEVA=; b=WQV+/WdDh8I/zwwwpRq/2aYepPcMfGhbrdMTUHCYiHV9Z+sJ/Q6ftIuEgAfnhQTlaVKGFy Tq6+pHrlKiUsXNBA== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 14191136E5; Wed, 17 Jul 2024 11:31:37 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id gw7gBJmrl2YPTAAAD6G6ig (envelope-from ); Wed, 17 Jul 2024 11:31:37 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id C8636A0987; Wed, 17 Jul 2024 13:31:32 +0200 (CEST) Date: Wed, 17 Jul 2024 13:31:32 +0200 From: Jan Kara To: Jeff Layton Cc: Alexander Viro , Christian Brauner , Jan Kara , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Chandan Babu R , "Darrick J. Wong" , Theodore Ts'o , Andreas Dilger , Chris Mason , Josef Bacik , David Sterba , Hugh Dickins , Andrew Morton , Jonathan Corbet , Dave Chinner , Andi Kleen , Christoph Hellwig , Uros Bizjak , Kent Overstreet , Arnd Bergmann , Randy Dunlap , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mm@kvack.org, linux-nfs@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v6 5/9] Documentation: add a new file documenting multigrain timestamps Message-ID: <20240717113132.dvzsczxjr67224bx@quack3> References: <20240715-mgtime-v6-0-48e5d34bd2ba@kernel.org> <20240715-mgtime-v6-5-48e5d34bd2ba@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240715-mgtime-v6-5-48e5d34bd2ba@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: B3BE21C0029 X-Stat-Signature: 8e3mmd1gq1w7sd7mcak53r6ujanpm6jo X-HE-Tag: 1721215898-78621 X-HE-Meta: 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 HlTSbflA IssHDBb4OLbTibz7ZneqIjhGk9JJwkQLa9mqrCvlUVNhatk5zW16NlqjJ2uY7ThVD8AzBOTDCQvAd3tQjK2BsoWGKSypEm2xLljlExUwuKBjwYYsBcknbd5JhNH60N8FXbBgtLS+6hKD11fxEkoSK33NP9n9qciPam4s7GQrb6nUMLdfQFEMBbDAmkh8/LR+NY+r46CBic+tXOTYbIIZPOuY1d2uhOavkZvrd8NrDN5Ep58gMiWQEYeI0ZbYy9cNj/8y0MtKd4t/3IxrYStAYicm6++NOvuxBf/H3xfsABR/XrIEcNnsMoxonrpumYAhSPFq1eGrQpxp4GcBLy84DC3zgN2KTPKtY1CRCtwSodX2oLirArb2XCSUmeBZMOZfNdj46qZvaj1selIGy5xe21HL63djo9zX5xUB+e+gJ9Blq70fuFOkTM03Y3Q== 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: List-Subscribe: List-Unsubscribe: On Mon 15-07-24 08:48:56, Jeff Layton wrote: > Add a high-level document that describes how multigrain timestamps work, > rationale for them, and some info about implementation and tradeoffs. > > Reviewed-by: Josef Bacik > Signed-off-by: Jeff Layton One comment below. With that fixed feel free to add: Reviewed-by: Jan Kara > +Implementation Notes > +==================== > +Multigrain timestamps are intended for use by local filesystems that get > +ctime values from the local clock. This is in contrast to network filesystems > +and the like that just mirror timestamp values from a server. > + > +For most filesystems, it's sufficient to just set the FS_MGTIME flag in the > +fstype->fs_flags in order to opt-in, providing the ctime is only ever set via > +inode_set_ctime_current(). If the filesystem has a ->getattr routine that > +doesn't call generic_fillattr, then you should have it call fill_mg_cmtime to > +fill those values. I think you should explicitely mention that ->setattr() implementation needs to use setattr_copy() or otherwise mimic its behavior... Honza -- Jan Kara SUSE Labs, CR