From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f173.google.com (mail-pf1-f173.google.com [209.85.210.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 87C8D2E9ED1 for ; Wed, 22 Oct 2025 18:12:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761156761; cv=none; b=SNRBtKJIaPtpZyhWaZpWeTGFcbRg/JI6FucMZG7Rx4p28FUcVZw7IRGaPtfP0J89ESQBrwlI4q1EaG6nmy3JGO33Tkza6jgg7dG/1T6XzVHiIzGkRfNVpJMRFoaTiofhMqyOCsFOwUlwQ6mM8TzgO/IY4+n4Nc/SBFj5RteNSmc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761156761; c=relaxed/simple; bh=L3H3gsvk+jEZsW0PrATObZIO7dMoEWR3ceyCKKKxT6o=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=rT24npPkeRc/TAOmYco6BCJJz2bcAm4QQHHXyuIPUmxhjyN3kctmsVyYalYPDGwa/E4lOCWYTr9yYm671iYdCLvTGNonbu+quGOHv4e/iC/esE4fOQXTKuC36F4uuqpoU/pQLjK0ldpQQCkXbQAbswvuycprXeWmMcfXZm46CmA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=G0Sy0WMG; arc=none smtp.client-ip=209.85.210.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="G0Sy0WMG" Received: by mail-pf1-f173.google.com with SMTP id d2e1a72fcca58-796f9a8a088so6522498b3a.1 for ; Wed, 22 Oct 2025 11:12:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1761156760; x=1761761560; darn=vger.kernel.org; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-transfer-encoding:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=L3H3gsvk+jEZsW0PrATObZIO7dMoEWR3ceyCKKKxT6o=; b=G0Sy0WMGaVhEyLNLbZrQbxDy1xD4EKYWgQu3CrW2I87O3DqmKrvJFReLJe47r7GsVA SJhtkmx92BYSi+Ft46QxG1u2IYkd0u6G6yBA3nHX95fJD2+vy7WAjxfw6oPUaJUhIcGC l7EUmc3deb1qapLgdkCzheRoDBdQBFR1ClyFDHBkVBd7wW5gxDnWCM/IqJ250YfoHX9k DfGz5bvw34FP2x2//qkrYpiId4PTfGmm02UDT+rqiwd89jEUXYldHkjeEIHcQ6TZVmHk KHGT/5AApvR6sParWYnOLtvgBv6kGai1Jg1i/zNI3q6DIOAXfmsjsklO1ooX8E5PdRsG zEFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761156760; x=1761761560; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-transfer-encoding:mime-version:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=L3H3gsvk+jEZsW0PrATObZIO7dMoEWR3ceyCKKKxT6o=; b=gjgPvo6NnVpz3B4EEAfRTCE5ddtWvIRfXqr6/z/xkcVBfYgyqK2DxGfA1zgdMTc9wF OjevK9imsnQ3z6b2Osi6B7yZYqMEjQiubQ/lO+zAGcmXo6OWlG0FlT3I+DKkjFtFbVO2 CpLz7O2lL2BMD5HPE+dSp+rxmv4Rqo/TyMgWvNcnMXLgDAsyEyLgPWnTpId2IrBa3IM0 jxcqVg5VzZ8DdYMkZiE+nVI/hY0XsyvtZCetLoS9rk+yex522WW6IIVBzHeVht/y5daj O+OKGmle9WoYeYHFJbr65WtqDjBRI9hnMOKcoNJMSY2LoAqRsOtKuc2LeMoUp6yVexxU bBpA== X-Forwarded-Encrypted: i=1; AJvYcCUFG1tibkzXV8afyLxfJLp3I6LyhcEYE8q5fyvCHanlLV4TQi1ncbcP+d0mZ18MvCg8PsoiV0FpybWrhY4=@vger.kernel.org X-Gm-Message-State: AOJu0YynrMUxzX/Xw2RaTnud7vDrAeBQ9SLgESbtHLSA/ZYpy9CTkELA Pfn5HNcgAkyUwbDYE9pYVyaGza1/es+19UWGn8itP8/K1yPFnEA9WbxG17fAojr1vpuS+g== X-Gm-Gg: ASbGncuWGtlWmiLSnooe+bPFBkD3tDKVmXDQV3wIfNNfkHKAwER1TW6xY1t+imA8CLH echFba7I7yJDCNn5pj0nur20PFMVQx1Dm7zRfa7lRnK572pfKDULYOw0Nk7jjBS9YrT3s6MpSje JKOOlvbP91+fhu1cAfMAQHhVT8ue44h5tw8kaSZKYRPzRLSISHry5kNxrLjygSfBqLPHdtMrod/ svugzFLaVFgm6eai4RcrRHVPGJsDkI7nvleeDE8su0fpbs7L71WjQbkI5G5aWVO9eF+5EbxzUv/ KD/iRFPfIjJxBJFD2ca0U/ApipH0EdaMGKmgAY5qpbumanbiLJ00jp8AzAc8RwlBrWqPZz+YMLn kqk9pX8JktMmyCSorIYbXU2qcGEyzxriM6v50VHcp36vguHZqJByyADsSHp7g2Kq/+Xx/qfPtRN FvRJaJ X-Google-Smtp-Source: AGHT+IE9ukly3OsSJtf/F5Pi5q/3u1rh2/j7Gpz3fL8FIoDXhYOFoguBVAVtJ0gXkaH9zj9KjLEqdQ== X-Received: by 2002:a05:6a21:328a:b0:248:86a1:a253 with SMTP id adf61e73a8af0-334a8564096mr29786646637.15.1761156759601; Wed, 22 Oct 2025 11:12:39 -0700 (PDT) Received: from localhost ([2405:201:3017:184:2d1c:8c4c:2945:3f7c]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7a22ff158bdsm15487022b3a.16.2025.10.22.11.12.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Oct 2025 11:12:39 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 22 Oct 2025 23:42:32 +0530 Message-Id: Cc: "Alexander Viro" , "Christian Brauner" , , , "Aleksa Sarai" , "Pavel Tikhomirov" , "Jan Kara" , "John Garry" , "Arnaldo Carvalho de Melo" , "Darrick J . Wong" , "Namhyung Kim" , "Ingo Molnar" , "Andrei Vagin" , "Alexander Mikhalitsyn" Subject: Re: [PATCH v2 1/1] statmount: accept fd as a parameter From: "Bhavik Sachdev" To: "Miklos Szeredi" X-Mailer: aerc 0.20.1 References: <20251011124753.1820802-1-b.sachdev1904@gmail.com> <20251011124753.1820802-2-b.sachdev1904@gmail.com> In-Reply-To: On Wed Oct 22, 2025 at 10:02 PM IST, Miklos Szeredi wrote: > What's wrong with statx + statmount? We would like to get mountinfo for "unmounted" mounts i.e we have an fd on a mount that has been unmounted with MNT_DETACH. statmount() does not work on such mounts (with the mnt_id_unique from statx), since they have no mount namespace. These mounts also don't show up in proc. v1 of this patch tried a different approach by introducing a new mount namespace for "unmounted" mounts, which had a bunch of complications [1]. The cover letter for this patch also has more information [2]. We want to support checkpoint/restore of such fds with CRIU [3]. [1]: https://lore.kernel.org/all/20251006-erlesen-anlagen-9af59899a969@brau= ner/ [2]: https://lore.kernel.org/all/20251011124753.1820802-1-b.sachdev1904@gma= il.com/ [3]: https://github.com/checkpoint-restore/criu/pull/2754 Kind regards, Bhavik