From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f172.google.com (mail-il1-f172.google.com [209.85.166.172]) (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 6290D2F1FED for ; Mon, 25 Aug 2025 13:56:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756130166; cv=none; b=nLIo50ZHlQLlmAPYOdGBYdgrBjGRBnH2Vnes5cVDR3dPhvOtjmnAm5hlwltBLnmW8ilsBAjSAj2VP8PF35GX1KyQJ6dSTfv1z7MqwXlNZ6c+TWYBKgTVNKhEeC5/AufkLfkKrAAHKseMWRFLbecpSEBEjD5ax5DbRS6BHItkW6s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756130166; c=relaxed/simple; bh=uTCLex4r+CcOhhp0Jw1xbazf6aFLqhbTTS7XiB9UMvk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Qc1H84RnOVDNN7bOzB7VvHCtInnlptYmodJ4nG9GbRK1tGIGKGHcXtLTh+ufS95qqmabh8hNvJxYDgiSx15VVovpEZ8PQhtS7x5FoNpKM7ilQcR+xuC+TbZKM8H0OAnA19h0iV+A3SpE1lStTtvL8JRgHrWQr84Y0HYkwSaeaBU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b=Z0ejFYse; arc=none smtp.client-ip=209.85.166.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b="Z0ejFYse" Received: by mail-il1-f172.google.com with SMTP id e9e14a558f8ab-3e668360ec7so26253005ab.1 for ; Mon, 25 Aug 2025 06:56:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1756130163; x=1756734963; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=+bj16z3bAVbIZz7VeQgjGNlWSy6Fqh6GjG5p/aTnAY0=; b=Z0ejFYsePerMbR0np2UCURp6B5gR2IU8MemNn/750ldCjktwcIj+TQ+eOpFyxNZX+I EFJ7/MK0LigcIp0tmXqqmeAsSlrZKn/O2XrU6prlpzdTbDr66jYI83uMYNb3l1OlE5hb mOZJfnYYQSG5PsOlpQP1AldLBhGqxmDYp6n1KKRWq6e+JOhryXM9rPyk9tsnT6ydx1oS 4bmE2rJcDR8CMTX3Cr703ifBMy8jYtBsr1mhgKnyO56g9WP3qfQhi23qZH+KCKpew9Kg rXTbzKD91M4Cvyl7lsK9gwoSCLyfRM2ifi5PfZu+N0T3358Q94Qk1AFBJIaBw76Ahas1 Xqbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756130163; x=1756734963; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=+bj16z3bAVbIZz7VeQgjGNlWSy6Fqh6GjG5p/aTnAY0=; b=s+u6Jvyz4bVDy51zENZXEFJB0fmJjaJ5jBkAc/CiMiKQ+5HGbgZRJuqgwlD4G6sak2 7vSNsti63QOX6/d/UKWxJq3QurmMlTGAYddvpLRszlxaGVwUvpwDmol1RS9Sr15xvh4s 7vpO6sSMb5LLs9RLc+ZcJSfmNMRJQtbWQz9jr8KTnGuuFJBDoS+G1eMnbL6YocmmT5wJ T2lKZMpGlnRnJoQM6m2pEhW4Vem3wGBTTC4eQF0gT7t765YOWZ12Pz5kne1r6YlmGF4p aXbWY8urwbbqCqMVIx2Sm6GgRTHd6KEvMNZLqdbCywdiEilJ00jkgQC4jZp8+uyQgctX SlTA== X-Forwarded-Encrypted: i=1; AJvYcCV/YyzmXv2daUR2FECmK1rc8J7zhqdDJQb6nO3GNt39BA2azAuyBt69hDJ+toireRTyFs06eY2vWoNWr7o=@vger.kernel.org X-Gm-Message-State: AOJu0Ywrwz8fXSIq9TMI8aqba9b+8VZ65XwORz0Ih16kV9HcyZmXbqf2 96wTmiiihX87ut1GKF6Ri3Oh1gDHIzz8bZpHo1FQ4/f1EGNwgYG9kQEtekhG4rbzfMo= X-Gm-Gg: ASbGncsKnpB4ZOgBPWsTRLRTBRgrZoVccSr65vwxhM3SQCSqqT9myB/Ts/TmYZT8hCx PZE+CN9dB1LT7BP627VN7oPzWvJDZ15nWaiuCBKxobz4kba/FvoE4L/0LiBcpn8FhI/p7QnP7Ny i6AUdMUNFqcdcjKxGZ/K4/FN2X65+xz2Lnh2I2lG63w/vCkvWHf2yKJiSyeZe3RufT1Xmwmq9p5 FcBcVFWMwA2x++f0PPSTvG6o9pp8qLqLffM/n1+t0aXfRNuanexlrBspgujOrbBfh0EzJ7GiFZy GZQWWEBDU0+U8Rq315bUA9dm/iMpmMnuEzKmPSclEQV9zh1aZtngb/01uC3UdJciSjnM8MIpe8A lWq7p9FZ1P6uv8bnynAASyCfpuAYuZg== X-Google-Smtp-Source: AGHT+IEiq20Lr6w+nHnroyq/OSDP6bjRqBGwYdseaIsmpNKgrJv38nh2DaKDNtgxmvXhu4eboRHU1Q== X-Received: by 2002:a05:6e02:170d:b0:3ec:4b19:1cff with SMTP id e9e14a558f8ab-3ec4b1927b2mr76913505ab.7.1756130163389; Mon, 25 Aug 2025 06:56:03 -0700 (PDT) Received: from [192.168.1.116] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id e9e14a558f8ab-3ea4e45a717sm50317145ab.31.2025.08.25.06.56.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 25 Aug 2025 06:56:02 -0700 (PDT) Message-ID: <36f30d8d-02fb-4579-b527-16da24cdc856@kernel.dk> Date: Mon, 25 Aug 2025 07:56:02 -0600 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] loop: fix zero sized loop for block special file To: Yu Kuai , ming.lei@redhat.com, hch@infradead.org, yukuai3@huawei.com, rajeevm@hpe.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, johnny.chenyi@huawei.com References: <20250825093205.3684121-1-yukuai1@huaweicloud.com> Content-Language: en-US From: Jens Axboe In-Reply-To: <20250825093205.3684121-1-yukuai1@huaweicloud.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/25/25 3:32 AM, Yu Kuai wrote: > static loff_t lo_calculate_size(struct loop_device *lo, struct file *file) > { > - struct kstat stat; > loff_t loopsize; > int ret; > > - /* > - * Get the accurate file size. This provides better results than > - * cached inode data, particularly for network filesystems where > - * metadata may be stale. > - */ > - ret = vfs_getattr_nosec(&file->f_path, &stat, STATX_SIZE, 0); > - if (ret) > - return 0; > + if (S_ISBLK(file_inode(file)->i_mode)) { > + loopsize = i_size_read(file->f_mapping->host); > + } else { > + struct kstat stat; > + > + /* > + * Get the accurate file size. This provides better results than > + * cached inode data, particularly for network filesystems where > + * metadata may be stale. > + */ > + ret = vfs_getattr_nosec(&file->f_path, &stat, STATX_SIZE, 0); > + if (ret) > + return 0; > + > + loopsize = stat.size; > + } Gah, that was pretty silly... -- Jens Axboe