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[209.85.208.46]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-658b46ac0e8sm4658858a12.34.2026.01.30.16.15.04 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 30 Jan 2026 16:15:04 -0800 (PST) Received: by mail-ed1-f46.google.com with SMTP id 4fb4d7f45d1cf-658b511573cso4635801a12.0 for ; Fri, 30 Jan 2026 16:15:04 -0800 (PST) X-Forwarded-Encrypted: i=1; AJvYcCW3hkH6wc6hF1JjvnXFSU9VoBWX2VyBeYojFzTKNBFcaxZ5jo78AWTtgRAUfJN/PUIK8ibMsZrFuw==@kvack.org X-Received: by 2002:a05:6402:1d54:b0:64b:4f44:60ef with SMTP id 4fb4d7f45d1cf-658de593957mr2779765a12.27.1769818504441; Fri, 30 Jan 2026 16:15:04 -0800 (PST) MIME-Version: 1.0 References: <2026012715-mantra-pope-9431@gregkh> <20260128045954.GS3183987@ZenIV> <20260129032335.GT3183987@ZenIV> <20260129225433.GU3183987@ZenIV> <20260130070424.GV3183987@ZenIV> <20260130235743.GW3183987@ZenIV> In-Reply-To: <20260130235743.GW3183987@ZenIV> From: Linus Torvalds Date: Fri, 30 Jan 2026 16:14:48 -0800 X-Gmail-Original-Message-ID: X-Gm-Features: AZwV_QjK3epqif7-e_sBGUc-n0f418Z3nV80PkvQC8yX5DIdQ4ynfWKt9EE0KMI Message-ID: Subject: Re: [PATCH v4 00/54] tree-in-dcache stuff To: Al Viro Cc: Samuel Wu , Greg KH , linux-fsdevel@vger.kernel.org, brauner@kernel.org, jack@suse.cz, raven@themaw.net, miklos@szeredi.hu, neil@brown.name, a.hindborg@kernel.org, linux-mm@kvack.org, linux-efi@vger.kernel.org, ocfs2-devel@lists.linux.dev, kees@kernel.org, rostedt@goodmis.org, linux-usb@vger.kernel.org, paul@paul-moore.com, casey@schaufler-ca.com, linuxppc-dev@lists.ozlabs.org, john.johansen@canonical.com, selinux@vger.kernel.org, borntraeger@linux.ibm.com, bpf@vger.kernel.org, clm@meta.com, android-kernel-team Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 07F6D40006 X-Stat-Signature: porwqq85wanhun6o4oitci13rj6k5hjj X-Rspam-User: X-HE-Tag: 1769818507-562617 X-HE-Meta: U2FsdGVkX1/ymm3IYUlJu6EsPkH54uT8KRu0NKojiHkBCLtiVdZxtt/x6f8E7SHcy8FRkX3EkcUOKZodOOnSYU5ZlIBBdR+y+LM7FDxSpl7z/h9zw/zogNKpqizGVoyflYXW+BX4HcQNS3g/0KBaHPeSLuanlM/IjKPBURaQKrVmtV8Bixs0cPXh17F/WALSUtC9Jm6hT9qrF6b4aemqXZZVEBoDR4vB8k++RrZ9tNZ7p5cnYjglUNFXBqzulgVnoxgjvQVB8epCpUJhIOELRy0bhBDpWpb+VEWILf0J/v5xlHraq5Qh7VNPe+/+UmyqACsAAN5hQmK/+r0I1CdO6ogbfvP3SO90fmvE1pw5iXOFsKAnVGqIf9jaZrzlrOFNwVccwXL1TSQlB5k02bXqbzfLfuyVZhBT21XFNmiJF9DXkAW8fa89zkQR/dKa6JvZ6/EliEG/oEvLqHKjW7u8NR2hVek8/sUG8P1iGkVcR5Z4rlvAW3PjZeYr+tBJZ7yDSyE7s+BoPJRW2/oz0eB+4qUJRdLvAKAdl1UDmHxnV47mpCct9gmqMgfvi/MELPYdSSySYAyKrFyv38NR9DlSvYOe4Vyt2GsszgywKOndZ3diMq4XO7p6twkRwlC/Mc9Pec01FQVD9ldALTHzdQtzX6xDexSGoHn/5CjxCLgX2btIKLCHgcz+NW2WxVSI14axMMAForwqNN1UeB7FGGEHCI42lRGO2TgIwmey/uopPvn3husa+0cGTRRmFQYgAPnelxk02G7Zjvx+1uXG6IA+jR2ytOar6etVJhOzMNXssQMlPFG3h5cHcn8IQK+utUe3YuRrWFvCUexcofcQYLU87hSGHapKrj4HDSp39blKlOBE8aIDnOK96dnM9oTWUDxt38p6wthoAv4sQNOHbPzz7Mr/dw4IEJqMezA7Xh59G8HCMlu31hAY4LnYgvCuWGAIJ/6+tuHuoDgahnkPCEd hqCxRWNu 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 30 Jan 2026 at 15:55, Al Viro wrote: > > So we have something that does O_NDELAY opens of ep0 *and* does not retry on > EAGAIN? > > How lovely... Actually, I think that is pretty normal behavior. Generally, O_NDELAY and friends should *NOT* turn locks into trylocks - because user space has no sane way to deal with kernel lock issues, and user space simply shouldn't care. So O_NDELAY should be about avoiding IO, not about avoiding perfectly normal locks. Of course, that horrendous driver locking is broken, since it holds the lock over IO, so that driver basically conflates IO and locking, and that's arguably the fundamental problem here. But I suspect that for this case, we should just pass in zero to ffs_mutex_lock() on open, and say that the O_NONBLOCK flag is purely about the subsequent IO, not about the open() itself. That is, after all, how the driver used to work. Linus