From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0355812E48; Wed, 17 Jul 2024 11:31:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721215900; cv=none; b=LeucVaHtcJl444bdCJWsUwL4hoAcGZ9CcY7Q34Pzesb75XtAZ5c9QWmln1LTrg9m127Tdi2WZziT5FQrRYlTbj0iJF3RVJrsRLwWcbLonKNVRhwArOPUqhFbnj787RwX5I27MNUZ472CSLZBbs7E1x+R76rOn9ySkBq/T8s1Yhk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721215900; c=relaxed/simple; bh=C09a0DDosOVNcklWN3W/ZdaKgvfbgXSiHfyoidPujm8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XahlvW5hk2aEJJ3OFGXlPwYeVHqoRQubMCFXJNjI95nupNZvp3FLVjqT/VlmQbsbdf3tW4sbQ3Wn+rLGi3mxlqu80szY5lERu05KYHpfn6MMW3yLu2mfWJyy7blLNGK8xb03uCqI/BkMywKwcirmnMtgq2bVL7+kMzEnaGtGZzE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz; spf=pass smtp.mailfrom=suse.cz; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=Rykqp0CY; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=WQV+/WdD; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=Rykqp0CY; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=WQV+/WdD; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.cz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="Rykqp0CY"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="WQV+/WdD"; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="Rykqp0CY"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="WQV+/WdD" 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== Authentication-Results: smtp-out1.suse.de; none 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> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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-Spamd-Result: default: False [-3.80 / 50.00]; BAYES_HAM(-3.00)[99.99%]; NEURAL_HAM_LONG(-1.00)[-1.000]; MID_RHS_NOT_FQDN(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-0.998]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_TWELVE(0.00)[33]; RCVD_VIA_SMTP_AUTH(0.00)[]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; MISSING_XM_UA(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[zeniv.linux.org.uk,kernel.org,suse.cz,goodmis.org,efficios.com,oracle.com,mit.edu,dilger.ca,fb.com,toxicpanda.com,suse.com,google.com,linux-foundation.org,lwn.net,fromorbit.com,linux.intel.com,infradead.org,gmail.com,linux.dev,arndb.de,vger.kernel.org,kvack.org]; R_RATELIMIT(0.00)[to_ip_from(RLj8qd95s75qu36yfn9qkwxfo3)]; FROM_EQ_ENVFROM(0.00)[]; RCVD_TLS_LAST(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,suse.com:email] X-Spam-Flag: NO X-Spam-Score: -3.80 X-Spam-Level: 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