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Mon, 25 Aug 2025 22:17:57 +0000 (GMT) Received: from mlperfr9.3-rocky.novalocal (unknown [192.58.206.35]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by p1lg14881.it.hpe.com (Postfix) with ESMTPS id AC17E805E16; Mon, 25 Aug 2025 22:17:55 +0000 (UTC) Received: from mlperfr9.3-rocky.novalocal (localhost [127.0.0.1]) by mlperfr9.3-rocky.novalocal (Postfix) with ESMTPS id 66EA8A0A40A4; Mon, 25 Aug 2025 22:17:51 +0000 (UTC) Received: (from rocky@localhost) by mlperfr9.3-rocky.novalocal (8.16.1/8.16.1/Submit) id 57PMHpaO3714509; Mon, 25 Aug 2025 22:17:51 GMT From: Cloud User 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 Subject: [PATCH 2/2] loop: use vfs_getattr_nosec for accurate file size Date: Mon, 25 Aug 2025 22:17:41 +0000 Message-ID: <20250825221741.3714488-3-rajeevm@hpe.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20250825221741.3714488-1-rajeevm@hpe.com> References: <20250825221741.3714488-1-rajeevm@hpe.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-GUID: rCeUDlGs_pOpvPyyC3VS-UDJtfw8MBw_ X-Proofpoint-ORIG-GUID: rCeUDlGs_pOpvPyyC3VS-UDJtfw8MBw_ X-Authority-Analysis: v=2.4 cv=S8vZwJsP c=1 sm=1 tr=0 ts=68ace115 cx=c_pps a=FAnPgvRYq/vnBSvlTDCQOQ==:117 a=FAnPgvRYq/vnBSvlTDCQOQ==:17 a=2OwXVqhp2XgA:10 a=MvuuwTCpAAAA:8 a=ky6m8zXAD6jKsvyDoWcA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwODI1MDIwMCBTYWx0ZWRfX9HdBCjfc5FGJ 0Te7N5JJm8c/S2+/gQd3RnK1Ezl+H8hbEkhicU2esgdxB4coM7BiAdM0X7WjFYn7P75quLhaMIO vdqYHV1gC3pE7OBTF3pdO4oVejRdtVCnZiNytsXS3QXyJ+gUSy0nr3iBq6tPg4pnpb0M31lgbnj gQLxCiyi8OgNxDYLicifAKZ1GeHCzN1hIk76HLxkn7X8nUIgmTUdMiLP2pysNiXrG/IUf/Rk8ms VlX5g/1rNZgxjBIFaJ/2zEMe3Q3saeX/qm5/vX+7iZCn9KxywC4aNU6JkG20bNTBbP1n48wluoG ooL161Nb46gSwOlPMb4pc3+N+6DC/PjLfgkwGujf0bWtkFtsTMJlkQ9rq2OZ+OK1GJzGgZGMUIX qHz07VnBKcvsZrfxcNuAl+YaE5fo0iDoUr9Gu6hAgrAc6eLidY/ry7NyEzZldYsaujoGyPvc X-HPE-SCL: -1 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-08-25_10,2025-08-20_03,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 malwarescore=0 clxscore=1015 spamscore=0 bulkscore=0 mlxlogscore=999 lowpriorityscore=0 phishscore=0 priorityscore=1501 impostorscore=0 mlxscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2508250200 From: Rajeev Mishra In lo_calculate_size(), use vfs_getattr_nosec() for non-block files. For block files, continue using i_size_read(). This improves size accuracy on network and distributed filesystems. Signed-off-by: Rajeev Mishra --- drivers/block/loop.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 0e1b9eb9db10..a6214ae40ef0 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -139,9 +139,24 @@ static int part_shift; static loff_t lo_calculate_size(struct loop_device *lo, struct file *file) { + struct kstat stat; loff_t loopsize; - /* Compute loopsize in bytes */ - loopsize = i_size_read(file->f_mapping->host); + int ret; + + /* + * Get the accurate file size. This provides better results than + * cached inode data, particularly for network filesystems where + * metadata may be stale. + */ + if (S_ISBLK(file->f_inode->i_mode)) { + loopsize = i_size_read(file->f_mapping->host); + } else { + ret = vfs_getattr_nosec(&file->f_path, &stat, STATX_SIZE, 0); + if (ret) + return 0; + loopsize = stat.size; + } + if (lo->lo_offset > 0) loopsize -= lo->lo_offset; /* offset is beyond i_size, weird but possible */ -- 2.47.3