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Thu, 01 Oct 2026 23:01:33 -0700 (PDT) Received: from localhost ([27.122.242.71]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-cc9f721a6afsm519169a12.0.2026.10.01.23.01.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Oct 2026 23:01:32 -0700 (PDT) Date: Fri, 2 Oct 2026 15:01:30 +0900 From: Hyunchul Lee To: NeilBrown Cc: Miklos Szeredi , Amir Goldstein , Kees Cook , Joel Granados , Richard Weinberger , Anton Ivanov , Johannes Berg , Breno Leitao , Andreas Hindborg , Jan Harkes , Hugh Dickins , Baolin Wang , Namjae Jeon , Carlos Maiolino , Alexander Viro , Christian Brauner , Jeff Layton , Jan Kara , linux-fsdevel@vger.kernel.org, fuse-devel@lists.linux.dev, linux-kernel@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-um@lists.infradead.org, codalist@coda.cs.cmu.edu, coda@cs.cmu.edu, linux-mm@kvack.org, ntfs@lists.linux.dev, linux-xfs@vger.kernel.org Subject: Re: [PATCH 1/7] VFS/xfs/ntfs: drop parent lock across d_alloc_parallel() in d_add_ci() Message-ID: References: <20260929034158.1455429-1-neilb@ownmail.net> <20260929034158.1455429-2-neilb@ownmail.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260929034158.1455429-2-neilb@ownmail.net> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261001_230135_044955_F8F9F252 X-CRM114-Status: GOOD ( 13.34 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org On Tue, Sep 29, 2026 at 01:36:01PM +1000, NeilBrown wrote: > From: NeilBrown > > A proposed change will invert the lock ordering between > d_alloc_parallel() and inode_lock() on the parent. > When that happens it will not be safe to call d_alloc_parallel() while > holding the parent lock - even shared. > > We don't need to keep the parent lock held when d_add_ci() is run - the > VFS doesn't need it as dentry is exclusively held due to > DCACHE_PAR_LOOKUP and the filesystem has finished its work. > > So drop and reclaim the lock (shared or exclusive as determined by > LOOKUP_SHARED) to avoid future deadlock. > > Signed-off-by: NeilBrown For the NTFS part, Looks good to me. Reviewed-by: Hyunchul Lee -- Thanks, Hyunchul