From nobody Tue Feb 28 15:37:51 2023 X-Original-To: freebsd-fs@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4PR1jH0NQKz3tbK3 for ; Tue, 28 Feb 2023 15:38:11 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::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) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4PR1jF4bV7z3ChQ for ; Tue, 28 Feb 2023 15:38:09 +0000 (UTC) (envelope-from kostikbel@gmail.com) Authentication-Results: mx1.freebsd.org; dkim=none; spf=softfail (mx1.freebsd.org: 2001:470:d5e7:1::1 is neither permitted nor denied by domain of kostikbel@gmail.com) smtp.mailfrom=kostikbel@gmail.com; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=gmail.com (policy=none) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.17.1/8.17.1) with ESMTPS id 31SFbqQS017500 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Tue, 28 Feb 2023 17:37:55 +0200 (EET) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua 31SFbqQS017500 Received: (from kostik@localhost) by tom.home (8.17.1/8.17.1/Submit) id 31SFbpGx017499; Tue, 28 Feb 2023 17:37:51 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Tue, 28 Feb 2023 17:37:51 +0200 From: Konstantin Belousov To: Alexander Lochmann Cc: freebsd-fs@freebsd.org Subject: Re: Understanding locking for buf Message-ID: References: <45d84dae-0ca9-95ed-f6fd-8243797453ff@tu-dortmund.de> <8e8d9145-9ee1-195e-3dd3-4e3166ac8abb@tu-dortmund.de> <8e9ac2ec-6387-27b0-5cdc-1d61dbe2c831@tu-dortmund.de> List-Id: Filesystems List-Archive: https://lists.freebsd.org/archives/freebsd-fs List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-fs@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8e9ac2ec-6387-27b0-5cdc-1d61dbe2c831@tu-dortmund.de> X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=4.0.0 X-Spam-Checker-Version: SpamAssassin 4.0.0 (2022-12-14) on tom.home X-Spamd-Result: default: False [-2.83 / 15.00]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.83)[-0.830]; DMARC_POLICY_SOFTFAIL(0.10)[gmail.com : No valid SPF, No valid DKIM,none]; MIME_GOOD(-0.10)[text/plain]; FROM_EQ_ENVFROM(0.00)[]; MLMMJ_DEST(0.00)[freebsd-fs@freebsd.org]; MIME_TRACE(0.00)[0:+]; R_DKIM_NA(0.00)[]; FREEMAIL_ENVFROM(0.00)[gmail.com]; RCPT_COUNT_TWO(0.00)[2]; ASN(0.00)[asn:6939, ipnet:2001:470::/32, country:US]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; TO_DN_SOME(0.00)[]; FROM_HAS_DN(0.00)[]; RCVD_TLS_LAST(0.00)[]; FREEMAIL_FROM(0.00)[gmail.com]; R_SPF_SOFTFAIL(0.00)[~all:c]; HAS_XAW(0.00)[]; ARC_NA(0.00)[] X-Rspamd-Queue-Id: 4PR1jF4bV7z3ChQ X-Spamd-Bar: -- X-ThisMailContainsUnwantedMimeParts: N On Mon, Feb 27, 2023 at 04:04:30PM +0100, Alexander Lochmann wrote: > > > On 27.02.23 15:23, Konstantin Belousov wrote: > > Not quite. Sync io (bread()) means that caller performs bufwait() on the > > buffer. It is still subject to the LK_KERNPROC ownership move. > Ehm. Has this behavior changed recently? > Our kernel version uses LK_KERNPROC to distinguish between sync and async > IO. How would that be possible if ownershipt changes in either case? > https://iris.cs.tu-dortmund.de/freebsd-lockdoc/latest/source/sys/geom/geom_vfs.c#L127 I think this is simply not _very_ accurate. It would still catch some sync operations.