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[49.186.89.135]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-a31ddf6ee7csm8703329a12.71.2025.01.14.13.21.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Jan 2025 13:21:07 -0800 (PST) Received: from dave by dread.disaster.area with local (Exim 4.98) (envelope-from ) id 1tXoLQ-00000005uTP-32bG; Wed, 15 Jan 2025 08:21:04 +1100 Date: Wed, 15 Jan 2025 08:21:04 +1100 From: Dave Chinner To: Theodore Ts'o Cc: Dmitry Vyukov , Kent Overstreet , Jan Kara , Kun Hu , jlayton@redhat.com, adilger.kernel@dilger.ca, bfields@redhat.com, viro@zeniv.linux.org.uk, christian.brauner@ubuntu.com, hch@lst.de, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, brauner@kernel.org, linux-bcachefs@vger.kernel.org, syzkaller@googlegroups.com Subject: Re: Bug: INFO_ task hung in lock_two_nondirectories Message-ID: References: <42BD15B5-3C6C-437E-BF52-E22E6F200513@m.fudan.edu.cn> <20250114135751.GB1997324@mit.edu> Precedence: bulk X-Mailing-List: linux-bcachefs@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: <20250114135751.GB1997324@mit.edu> On Tue, Jan 14, 2025 at 08:57:51AM -0500, Theodore Ts'o wrote: > P.S. If you want to push back on this nonsense, Usenix program > committee chairs are very much looking for open source professionals > to participate on the program committees for Usenix ATC (Annual > Technical Conference) and FAST (File System and Storage Technologies) > conference. The problem is that the Usenix/FAST paper committees will not reach out to OSS subject matter experts to review papers that they have been asked to review for the conference. Let me give you a recent example of a clear failure of the FAST paper committee w.r.t. plagarism. The core of this paper from FAST 2022: https://www.usenix.org/conference/fast22/presentation/kim-dohyun "ScaleXFS: Getting scalability of XFS back on the ring" is based on the per-CPU CIL logging work I prototyped and posted an RFC for early in 2021: https://lore.kernel.org/linux-xfs/20200512092811.1846252-1-david@fromorbit.com/ The main core of the improvements described in the ScaleXFS paper are the exact per-cpu CIL algorithm in that was contained in the above RFC patchset. That algorithm had serious problems that meant it was unworkable in practice - these didn't show up until journal recovery was tested and it resulted in random filesystem corruptions. I didn't understand the root cause of the problem until months later. These problems were all based on failures to correctly order the per-CPU log items in the journal due to the per-CPU CIL being inherently racy. The algorithm I proposed 6 months later (and eventually got merged in July 2022) had significant changes to the way the per-CPU CIL ordered operations to address these problems. IOWs, object ordering on the CIL is the single most important critical correctness citeria for the entire journalling algorithm and hence a fundamental algorithmic constraint for the per-CPU CIL implementation. However, the ScaleXFS paper does not make any mention of this fundamental algorithmic constraint - I did not publish anything about this constraint until the November 2022 patch set.... There were more clear tell-tales in the paper that indicate that the "research" was based on that early per-CPU CIL RFC I posted, but I won't go into details. I brought this to the FAST committee almost immediately after I was able to review the paper (a couple of days after the FAST conference itself). I provided them with all the links to public postings of the algorithm, detailed analysis of the paper and publicly posted code, etc. In response, they basically did nothing and brushed my concerns off. It would take weeks to get any response from the paper committee, and the overall response really felt like the Usenix people simply didn't care at all about what was obviously plagarised work. IOWs, the Usenix/FAST peer review process for OSS related papers is broken, and they don't seem to care when experts from the OSS community actually bring clear cases of academic malpractice to them... -Dave. -- Dave Chinner david@fromorbit.com