From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2B02C433F5 for ; Wed, 9 Mar 2022 12:05:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232613AbiCIMGT (ORCPT ); Wed, 9 Mar 2022 07:06:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231773AbiCIMGQ (ORCPT ); Wed, 9 Mar 2022 07:06:16 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2F334172251 for ; Wed, 9 Mar 2022 04:05:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646827516; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zK0rHTm7GvinAxjXqiUVa246YKg1D+hx4a2IrpzADzs=; b=T/T5wI9lmqiWX47cH3Vw939gA1pfRiY6/Bayf5zXrVoNjhOn97+/dHHEE96pkSe5nW2SIC EFLkOFpMSilbjnHvu6jnF+VLctL6ZdcSBHOx/qDDFdzS/oDay+us3Rpvrde1UfLNe2pFz+ 26GMZ7ZcdUoGW+FOEpADhJ9F8PAWAWw= Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-93-gUsAAKTDM2qjpI1EpclAFQ-1; Wed, 09 Mar 2022 07:05:15 -0500 X-MC-Unique: gUsAAKTDM2qjpI1EpclAFQ-1 Received: by mail-pf1-f200.google.com with SMTP id y2-20020a623202000000b004f6c2892ffeso1437350pfy.12 for ; Wed, 09 Mar 2022 04:05:15 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=zK0rHTm7GvinAxjXqiUVa246YKg1D+hx4a2IrpzADzs=; b=b/szHZugPWOMSUq0L49gzLBYbNyXCE0wDGJa1MixXmQ1O1nLbYi+OTR7YOTTnfr4J4 Owg2eU3OsfJ1HW2krqzXeaPJB8Myw4JW/7lXQpNEylbt8mzD+8WmX4b0CjbMxfBUdy6N IVewA5Co46TD2YXBK5XwEKPNtqga71gjKBFSSJbAUHms4NOpxt6VsWFGJ2Jf0QWOARuh 2EPYcZuIMqFFmRByYkomSQh6bF5TMSM7D/Yod7LEZOOec3NmobPnY+5nBiL8D8QuxO92 vP0xlh0ogPcBjZKNP1JZ/VxoNvJwp3bByoX0Tdm1+cW15wVgPOQcZZSgLkgoMEuPczDl VmXQ== X-Gm-Message-State: AOAM5304xFZV9B7cAVxklbgLWaHWD2LU//jROlRgZ+kqGk96ba8yUA0C LRQthS3Hdm/FJNnb568/RrkTEU0geNRgnIWsCxtfFpTBfZV8BZvOcISZiFpgbRQuzC0UzRyg4Ek nkmMpLVl6PSXw+kCd1MT7xivBcBUG+BeJrfnsnIMp7SHVZq8HbeV3ndYwzKnJj57a9twGBFA= X-Received: by 2002:a17:90a:f286:b0:1bf:9a1e:8f83 with SMTP id fs6-20020a17090af28600b001bf9a1e8f83mr6418607pjb.7.1646827513907; Wed, 09 Mar 2022 04:05:13 -0800 (PST) X-Google-Smtp-Source: ABdhPJziFSOrZwchP8PboBMDgmc3B8SfmgPxwS/u3mtxf4SWP9tlAJPFaImPnbrUhS+ZuungQKiAaQ== X-Received: by 2002:a17:90a:f286:b0:1bf:9a1e:8f83 with SMTP id fs6-20020a17090af28600b001bf9a1e8f83mr6418573pjb.7.1646827513446; Wed, 09 Mar 2022 04:05:13 -0800 (PST) Received: from [10.72.12.86] ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id 63-20020a630942000000b00372a99c1821sm2201309pgj.21.2022.03.09.04.05.09 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 09 Mar 2022 04:05:12 -0800 (PST) Subject: Re: [PATCH v5] ceph: do not dencrypt the dentry name twice for readdir To: =?UTF-8?Q?Lu=c3=ads_Henriques?= Cc: jlayton@kernel.org, idryomov@gmail.com, vshankar@redhat.com, ceph-devel@vger.kernel.org References: <20220305122527.1102109-1-xiubli@redhat.com> <87h788z67y.fsf@brahms.olymp> <87v8wn78jq.fsf@brahms.olymp> <84fc2bde-2fe8-ec78-1145-2cc010259f38@redhat.com> <87r17b72yf.fsf@brahms.olymp> From: Xiubo Li Message-ID: Date: Wed, 9 Mar 2022 20:05:06 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <87r17b72yf.fsf@brahms.olymp> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org On 3/9/22 7:58 PM, Luís Henriques wrote: > Xiubo Li writes: > >> On 3/9/22 5:57 PM, Luís Henriques wrote: >>> Xiubo Li writes: >>> >>>> On 3/9/22 1:47 AM, Luís Henriques wrote: >>>>> xiubli@redhat.com writes: >>>>> >>>>>> From: Xiubo Li >>>>>> >>>>>> For the readdir request the dentries will be pasred and dencrypted >>>>>> in ceph_readdir_prepopulate(). And in ceph_readdir() we could just >>>>>> get the dentry name from the dentry cache instead of parsing and >>>>>> dencrypting them again. This could improve performance. >>>>>> >>>>>> Signed-off-by: Xiubo Li >>>>>> --- >>>>>> >>>>>> V5: >>>>>> - fix typo of CEPH_ENCRYPTED_LONG_SNAP_NAME_MAX macro >>>>>> - release the rde->dentry in destroy_reply_info >>>>>> >>>>>> >>>>>> fs/ceph/crypto.h | 8 ++++++ >>>>>> fs/ceph/dir.c | 59 +++++++++++++++++++++----------------------- >>>>>> fs/ceph/inode.c | 7 ++++++ >>>>>> fs/ceph/mds_client.c | 2 ++ >>>>>> fs/ceph/mds_client.h | 1 + >>>>>> 5 files changed, 46 insertions(+), 31 deletions(-) >>>>>> >>>>>> diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h >>>>>> index 1e08f8a64ad6..c85cb8c8bd79 100644 >>>>>> --- a/fs/ceph/crypto.h >>>>>> +++ b/fs/ceph/crypto.h >>>>>> @@ -83,6 +83,14 @@ static inline u32 ceph_fscrypt_auth_len(struct ceph_fscrypt_auth *fa) >>>>>> */ >>>>>> #define CEPH_NOHASH_NAME_MAX (189 - SHA256_DIGEST_SIZE) >>>>>> +/* >>>>>> + * The encrypted long snap name will be in format of >>>>>> + * "_${ENCRYPTED-LONG-SNAP-NAME}_${INODE-NUM}". And will set the max longth >>>>>> + * to sizeof('_') + NAME_MAX + sizeof('_') + max of sizeof(${INO}) + extra 7 >>>>>> + * bytes to align the total size to 8 bytes. >>>>>> + */ >>>>>> +#define CEPH_ENCRYPTED_LONG_SNAP_NAME_MAX (1 + 255 + 1 + 16 + 7) >>>>>> + >>>>> I think this constant needs to be defined in a different way and we need >>>>> to keep the snapshots names length a bit shorter than NAME_MAX. And I'm >>>>> not talking just about the encrypted snapshots. >>>>> >>>>> Right now, ceph PR#45192 fixes an MDS limitation that is keeping long >>>>> snapshot names smaller than 80 characters. With this limitation we would >>>>> need to keep the snapshot names < 64: >>>>> >>>>> '_' + + '_' + '' '\0' >>>>> 1 + 64 + 1 + 12 + 1 = 80 >>>>> >>>>> Note however that currently clients *do* allow to create snapshots with >>>>> bigger names. And if we do that we'll get an error when doing an LSSNAP >>>>> on a .snap subdirectory that will contain the corresponding long name: >>>>> >>>>> # mkdir a/.snap/123456qwertasdfgzxcvb7890yuiophjklnm123456qwertasdfgzxcvb78912345 >>>>> # ls -li a/b/.snap >>>>> ls: a/b/.snap/_123456qwertasdfgzxcvb7890yuiophjklnm123456qwertasdfgzxcvb78912345_109951162777: No such file or directory >>>>> >>>>> We can limit the snapshot names on creation, but this should probably be >>>>> handled on the MDS side (so that old clients won't break anything). Does >>>>> this make sense? I can work on an MDS patch for this but... to which >>>>> length should names be limited? NAME_MAX - (2*'_' + )? Or >>>>> should we take base64-encoded names already into account? >>>>> >>>>> (Sorry, I'm jumping around between PRs and patches, and trying to make any >>>>> sense out of the snapshots code :-/ ) >>>> For fscrypt case I think it's okay, because the max len of the encrypted name >>>> will be 189 bytes, so even plusing the extra 2 * sizeof('_') - sizeof() >>>> == 15 bytes with ceph PR#41592 it should work well. >>> Is it really 189 bytes, or 252, which is the result of base64 encoding 189 >>> bytes? >> Yeah, you are right, I misread that. The 252 is from 189 * 4 / 3, which will be >> the base64 encoded name. >> >> So, I think you should fix this to make the totally of base64 encode name won't >> bigger than 240 = 255 - 15. So the CEPH_NOHASH_NAME_MAX should be: >> >> #define CEPH_NOHASH_NAME_MAX (180 - SHA256_DIGEST_SIZE) >> >> ? > That could be done, but maybe it's not worth it if the MDS returns -EINVAL > when creating a snapshot with a name that breaks this rule. Thus, we can > still have regular file with 189 bytes names and only the snapshots will > have this extra limitation. (I've already created PR#45312 for this.) > > But I'm OK either way. IMO your PR will always make sense no matter we will fix it in kclient side. Will leave this to Jeff :-) - Xiubo > Cheers,