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[2a02:3100:a979:9501:3df6:d7fa:8a5a:6c5]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-485885b1320sm792490f8f.27.2026.09.03.12.50.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Sep 2026 12:50:47 -0700 (PDT) Date: Thu, 3 Sep 2026 21:50:45 +0200 From: Karl Mehltretter To: Jan Kara Cc: Alexander Viro , Christian Brauner , Oleg Nesterov , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] super: remember whether freeze holds writer rwsems Message-ID: References: <20260903060855.4610-1-kmehltretter@gmail.com> 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: On Thu, Sep 03, 2026 at 12:40:42PM +0100, Jan Kara wrote: > This looks like one of these theoretical issues LLMs come up with. Frankly, > I just wouldn't bother. If the fs gets forcibly remounted RO due to > metadata errors, a frozen fs is likely the least of your worries. > You may be right that this is not worth fixing in generic VFS. I tried the real filesystem paths anyway: Without patch With patch ext2 next write hangs, unmount write and unmount complete gives three RCU warnings NILFS2 unmount gives three unmount completes cleanly RCU warnings These tests use FIFREEZE, FITHAW, and corrupted filesystem images. Other filesystems have similar error paths. The f2fs report fixed by 930c6ab93492 exercised the same sequence. The ext4 change d3476f3dad4a removed the analogous SB_RDONLY assignment because it confused filesystem freezing. The VFS patch only makes thaw release what freeze acquired. It is needed because these filesystems change SB_RDONLY outside the remount path. Should I send a v2 with the changelog limited to the reproduced failure, look at filesystem-specific fixes, or leave this alone? Thanks, Karl