From nobody Sun Nov 24 06:22:25 2024 Received: from szxga06-in.huawei.com (szxga06-in.huawei.com [45.249.212.32]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4AB151E1325; Thu, 7 Nov 2024 11:30:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.32 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730979026; cv=none; b=iAd6RbL6c+UaE8atfuXhXZF2KRxAJP6yed+dcS23jIG6aVSfpstvk0ND8hoZQYtjvcAM6rWy2KFEryHbXmR3dOVEZ8eMM3wyHgUi4AaTqygxtA+jVjTaOvzPpY0EF/MfRjmTgOG73+NRFVoJnn4JxwdCaYsxmm5jB7UoEQtbp/k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730979026; c=relaxed/simple; bh=tycehnml7nIskV1IKhFmTrfCzq+GzAVvOOf7z24DQ6k=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ZV4oQkk0156HYCp6on57juBQnKzHZSNMRQcJY1g9GCIcUfrE1Kc3Q7h+iOYal7Yp57o7Lt5YVxwwcE3jiHSnUMG+r1uxMyKusAEaGDWoRhrkcduGwIOQIbH3xFduly6BbNLQoL0+W8zlr0Ehx2kK6Ks/32hwMcPIf/9jv8bX+b4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.32 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.214]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4XkfWD6Ng5z2gL16; Thu, 7 Nov 2024 19:10:32 +0800 (CST) Received: from kwepemf100017.china.huawei.com (unknown [7.202.181.16]) by mail.maildlp.com (Postfix) with ESMTPS id 8E6621A016C; Thu, 7 Nov 2024 19:10:22 +0800 (CST) Received: from huawei.com (10.175.104.67) by kwepemf100017.china.huawei.com (7.202.181.16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 7 Nov 2024 19:10:21 +0800 From: Zizhi Wo To: , , , CC: , , , , , , , , , , Subject: [PATCH v2 1/5] cachefiles: Fix incorrect length return value in cachefiles_ondemand_fd_write_iter() Date: Thu, 7 Nov 2024 19:06:45 +0800 Message-ID: <20241107110649.3980193-2-wozizhi@huawei.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20241107110649.3980193-1-wozizhi@huawei.com> References: <20241107110649.3980193-1-wozizhi@huawei.com> 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 X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemf100017.china.huawei.com (7.202.181.16) Content-Type: text/plain; charset="utf-8" cachefiles_ondemand_fd_write_iter() function first aligns "pos" and "len" to block boundaries. When calling __cachefiles_write(), the aligned "pos" is passed in, but "len" is the original unaligned value(iter->count). Additionally, the returned length of the write operation is the modified "len" aligned by block size, which is unreasonable. The alignment of "pos" and "len" is intended only to check whether the cache has enough space. But the modified len should not be used as the return value of cachefiles_ondemand_fd_write_iter() because the length we passed to __cachefiles_write() is the previous "len". Doing so would result in a mismatch in the data written on-demand. For example, if the length of the user state passed in is not aligned to the block size (the preread scene/DIO writes only need 512 alignment/Fault injection), the length of the write will differ from the actual length of the return. To solve this issue, since the __cachefiles_prepare_write() modifies the size of "len", we pass "aligned_len" to __cachefiles_prepare_write() to calculate the free blocks and use the original "len" as the return value of cachefiles_ondemand_fd_write_iter(). Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up co= okie") Signed-off-by: Zizhi Wo --- fs/cachefiles/ondemand.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 470c96658385..bdd321017f1c 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -61,7 +61,7 @@ static ssize_t cachefiles_ondemand_fd_write_iter(struct k= iocb *kiocb, struct cachefiles_object *object =3D kiocb->ki_filp->private_data; struct cachefiles_cache *cache =3D object->volume->cache; struct file *file =3D object->file; - size_t len =3D iter->count; + size_t len =3D iter->count, aligned_len =3D len; loff_t pos =3D kiocb->ki_pos; const struct cred *saved_cred; int ret; @@ -70,7 +70,7 @@ static ssize_t cachefiles_ondemand_fd_write_iter(struct k= iocb *kiocb, return -ENOBUFS; =20 cachefiles_begin_secure(cache, &saved_cred); - ret =3D __cachefiles_prepare_write(object, file, &pos, &len, len, true); + ret =3D __cachefiles_prepare_write(object, file, &pos, &aligned_len, len,= true); cachefiles_end_secure(cache, saved_cred); if (ret < 0) return ret; --=20 2.39.2