From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.224.41 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793891497; b=s1y3jWw+b/m4VIQc/sTf4RINQBg+xSF8UQtLqt8yvl0xzG6rSjp3RnWmS5k+KyNaTYnI 4nSv+Kp9COQP5fgJaOoeR48cn8qfAw4a+RrFNYtDF3thJgEucsvFsV8q+kgUzS790rHsl 4mNfkdXDcOKdjX1aSWvA5qcRdPHMGAVavXTiYgKXTs4foSiP4E+WZ4qHq9TIKNcLR8Umm vFTXaWQTkKY3BtXJmfjJ5qGclST/T7nYDg5QMpVpk/EEZkwmzGGJM2zK70dKwgnjBYxE4 WrXKi/jvquskhMAiuFgTRGO0kznlOpSSFoQfWaLJexN26Yws1Sol9NKC9v7OjSjMueA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793891497; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: From:Date:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding: Message-Id:References:In-Reply-To:To:Cc:X-Mailer: X-Developer-Signature:X-Developer-Key; bh=Z4cDAXNUc3K0ZnV8t9qeV2IWpTEwGu9zEe368I5KRhs=; b=WIPSaMK94xi7X4VOMD9uzijAuMwuNE+N+Nc3NDOl6MooRrlO1HPfvmgNbDk87Yffk/TZ 3vfA+ze6/CoyqoQwIdE7rtKU6OyyJ3W6XvteX6s/dpH9ZUs2cXA4F83rV1+NZvoxJfIqK Sq9JCEue8+EfKtJM8dlksTH5kbIS+R0ixXRF2zFSHYK1ByPNqItlJ5hN4uldNXFidivCX UjTxotZBYd13pDABuzCeWNHYXhRHZ1tOvQ2oCJD0cjXnSK59tWpjGZY/kzVuKCvpf4vUR wGCxa21jjOkV8cPjPkZK50MoPsWJaerRj/Jk5g0AA+SJQ14b+roxYXr2bJZeOhO6KBQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none header.from=toxicpanda.com; spf=pass smtp.mailfrom=toxicpanda.com; dkim=pass header.d=toxicpanda.com header.i=@toxicpanda.com header.a=rsa-sha256 header.s=google header.b=Z7hjdC7K; arc=none smtp.remote-ip=74.125.224.41 Received: from mail-yx1-f41.google.com (mail-yx1-f41.google.com [74.125.224.41]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE0BD606A326 for ; Thu, 5 Nov 2026 15:11:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org BE0BD606A326 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=toxicpanda.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=toxicpanda.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=toxicpanda.com header.i=@toxicpanda.com header.a=rsa-sha256 header.s=google header.b=Z7hjdC7K Received: by mail-yx1-f41.google.com with SMTP id 956f58d0204a3-67a2bd0c297so2370263d50.2 for ; Thu, 05 Nov 2026 07:11:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=toxicpanda.com; s=google; t=1793891496; x=1794496296; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=Z4cDAXNUc3K0ZnV8t9qeV2IWpTEwGu9zEe368I5KRhs=; b=Z7hjdC7KFLenFl7FXbc8/a/MApH4kHG/F+vzQLiU7jpzn8lO6cElu0doYGbj7zW6Ol XiRFd3Qemnk/gzEpyoVOu+MXDDyoiLakMjm41/IcyK4QOo8WYNBP9K7fV3YkU6Yd7wS3 r3GVJMcySopCMpbM9zDGo2Sa6pNH4YpltbYwPugZWWrF/k07jhUbs+7HhB1soUccTi2/ RKHEP6tc5FUIRLvbzFWsr8YiSks4Ckpc75CQcgQgfcILuk9oTJLfNGYps+QifcaWuYn0 3xLycrA6gF6zQP4paYREno/oc7XHNjgHNrV0ApYL9YQbM/wEi5FwIa7aRlUT2kHEMPz1 Jedg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793891496; x=1794496296; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=Z4cDAXNUc3K0ZnV8t9qeV2IWpTEwGu9zEe368I5KRhs=; b=U/yLH+rrkvmcoX+ZgY7rLGq43KGEM2Ap02vFMAhSr9i2y31UE2il+IRmm8rWc8h9OC PeIHU62FmGF/hP6l3nCP4JyYBe/tdt9GVhBImDh3xppDvjp1ygFMsGOHGRWiy2e/khRv 5es3WKMT+yJloauKWZ4xU3ZXNJT3srp15e3TmsOeoDw+AJiNR/pSX0HdhF5TA5NnL5vC dEDzWBoSANLri2hqpT4TSvv1BGPGgq1wUwgKI0KfWlFEL3KKzNV7sIfcPpmhX6X5ena9 YpwvqsVd7NwsQBnJz3XSsS1dDFa5qmtZ59n0mClx0I/unPhoIEbO/IvvTUd5pgk4NX3L y9Gg== X-Forwarded-Encrypted: i=1; AKwUvByK9RyHz66POSs1rnEy8CO26S6tLJ5rOzP5DlPaDZ2y97qbr86jXPlk6x/yvqV8wP8mN1sOxAenkagaliQ=@vger.kernel.org X-Gm-Message-State: APuU4Z+gCnUcE+dqclyQhGL3u9mXcI/CNi5MC59AH8A+HahcR8YpP7p+ X5MWKs0IAxwTwIrIACsgcBn5uECz4XVJUDaCxVjWhRlPrD1YrqLI8YRwtBij4RMpE4o= X-Gm-Gg: AYBFou0PtIKPSq3qKaX3HjyjL/sG3m7v937x7VFen0I0lhr8gD76mRkdRaQH/wxnPD7 JIUBoy5ykxOHSYt/Acq7Mnwu1dkCK/DE42pTGdLo3+0p+X9o/Oiftx3qT9yHBbYCdqqs2HVu+Rm CvrPUKj1qkpt/J1ENThA8HmJiepOuHcfFbhre85xWYggqxyeTI0sploMkZtfnB5oOFsiXz//0XJ NjCcgzImDWu6jk/iyZIErxQR8xdcswIA/LswX0x6+N9UP5+l7zne6wN2w3PBSHG5xLVWehjNHNW UxTj55KchkXGKFOERMCYn/NI0YYAq2jLI+0kQOstFuI4Mt3/iOEFbNF/Umal4aobxTqeduYRZUN qdvesdfoKYcXDMWasLSTGJ2CLIDOeZGaopo/+GZQXphqimsqf45U4QoDQ68KQpeqPl8fRg3UUm7 B72wm9Lm3hXAfIsTLvabdhuKWUXzL4P5oFWPGwDHyIH5lrJD02dW9jkZQe8S6+vYOr1YQsl+/Kk UVYH5Jeoc6TxrNN74j3Y5eL2g9TjMINceCt5uVDjgyeEvDALLPSFZcnq11U6QoVrqan9QeSp8JC XLfwEPuqdIHjn9AWJpiApbcEMcHy/EDXJ6yGEU6sfKptvA== X-Received: by 2002:a05:690e:140f:b0:67b:e21d:93d0 with SMTP id 956f58d0204a3-67be21d95aemr4949251d50.51.1793891495619; Thu, 05 Nov 2026 07:11:35 -0800 (PST) Received: from toxicpanda.com ([153.61.196.251]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-67bee202a69sm3637395d50.5.2026.11.05.07.11.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Nov 2026 07:11:33 -0800 (PST) From: Josef Bacik Date: Thu, 05 Nov 2026 15:02:23 +0000 Subject: [PATCH RFC v3 31/90] cells: reserve the "spawn" slot X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261105-b4-cells-v3-31-bc9095937a84@toxicpanda.com> References: <20261105-b4-cells-v3-0-bc9095937a84@toxicpanda.com> In-Reply-To: <20261105-b4-cells-v3-0-bc9095937a84@toxicpanda.com> To: Christian Brauner , James Bottomley , Andrew Halaney , Jeremy Bingham , Tahera Fahimi , Serge Hallyn Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Josef Bacik X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=openssh-sha256; t=1793890933; l=1264; i=josef@toxicpanda.com; h=from:subject:message-id; bh=gcNNSOpmtg4LFK/nczfAl3jZs/cLgmyYRarla2n4+3E=; b=U1NIU0lHAAAAAQAAADMAAAALc3NoLWVkMjU1MTkAAAAgUBr36M/n0nWN0DNbnxwzIiCZez6MG JiruuNaSCI/zXsAAAAGcGF0YXR0AAAAAAAAAAZzaGE1MTIAAABTAAAAC3NzaC1lZDI1NTE5AAAA QNtLSJl0XJSKcO3eClfCZfC34206VfWEtH0ipup14MIhs4/yc0YDmKjrvowwvtET2E6oAPELu5C lO+QownXUowY= X-Developer-Key: i=josef@toxicpanda.com; a=openssh; fpr=SHA256:C8kOX2QUJCMqnCX+KEeoqRAjLo9L+ELOSH2NSAJHqGA A task of a cell can neither create a cell nor start a task in one. So far that looks like a side effect of the fact that no cellfd ever gets into a cell. Make it an explicit rule that does not depend on that. The rule fits the model: a cell can do what its slots hold, and the right to spawn is a slot like any other. cell_may_spawn() checks it where a cell is created and where a task is started in one. There is nothing to put into the slot yet, so it is always empty for a cell, and a task that is in no cell may always spawn. This patch only reserves the name. Nested cells can later be enabled by filling the slot. Signed-off-by: Josef Bacik --- kernel/cell/slots.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/cell/slots.c b/kernel/cell/slots.c index cc732c4e09f9..6ce8892f7908 100644 --- a/kernel/cell/slots.c +++ b/kernel/cell/slots.c @@ -165,6 +165,9 @@ SYSCALL_DEFINE5(cell_configure, int, cfd, unsigned int, cmd, if (IS_ERR(key)) return PTR_ERR(no_free_ptr(key)); } + /* Reserved. See cell_may_spawn(). */ + if (key && !strcmp(key, "spawn")) + return -EOPNOTSUPP; if (cmd == CELL_SET_STRING) { str = strndup_user(uvalue, 256); if (IS_ERR(str)) -- 2.55.0