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[49.180.185.123]) by smtp.gmail.com with ESMTPSA id oe14-20020a17090b394e00b0029fb85dca03sm121173pjb.25.2024.03.17.15.45.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 17 Mar 2024 15:45:55 -0700 (PDT) Received: from dave by dread.disaster.area with local (Exim 4.96) (envelope-from ) id 1rlzGK-003Lsm-1G; Mon, 18 Mar 2024 09:45:52 +1100 Date: Mon, 18 Mar 2024 09:45:52 +1100 From: Dave Chinner To: Phillip Susi Cc: linux-fsdevel@vger.kernel.org, Theodore Ts'o Subject: Re: Uneccesary flushes waking up suspended disks Message-ID: References: <877cieqhaw.fsf@vps.thesusis.net> <87h6h78uar.fsf@vps.thesusis.net> Precedence: bulk X-Mailing-List: linux-fsdevel@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: <87h6h78uar.fsf@vps.thesusis.net> On Fri, Mar 15, 2024 at 10:05:16AM -0400, Phillip Susi wrote: > Dave Chinner writes: > > > How do other filesystems behave? Is this a problem just on specific > > filesystems? > > I finally got around to testing other filesystems and surprisingly, it > seems this is only a problem for ext4. That's what I expected - I would have been surprised if you found problems across multiple filesystems... > I tried btrfs, f2fs, jfs, udf, > and xfs. xfs even uses the same jbd2 for journaling that ext4 does > doesn't it? .... because none of them share "journalling" code at all. They all have their own independent mechanisms for ensuring data and metadata integrity. ext4/jbd2 actually shares little code with other Linux filesystems - ocfs2 is the only other linux filesystem that uses jbd2. > I just formatted a clean fs, synced, and ran blktrace, then synced > again, and only ext4 emits a flush on the second sync. So this really sounds like it's just a bug in ext4/jbd2 behaviour and so there's no real general filesystem or infrastructure problem that needs to be fixed here.... Cheers, Dave. -- Dave Chinner david@fromorbit.com