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 78DF4C433F5 for ; Wed, 9 Mar 2022 10:11:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229561AbiCIKMj (ORCPT ); Wed, 9 Mar 2022 05:12:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229519AbiCIKMj (ORCPT ); Wed, 9 Mar 2022 05:12:39 -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 A8EF916A591 for ; Wed, 9 Mar 2022 02:11:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646820696; 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=Cbfb366ZkDSzxZK5jYsxwTNE/kSKHXFjtV5zW8Uhs+w=; b=iAE7svMQJrdnSIZ02b5SBFSfEXDTzfaiwAYZvdDaha33bY+5115ASBplDPqJdJeuCkajdA 7n1U6tp7qx6ETJw0uGv5bAE7MmWWE6NRXxYkFKDMoznt+/ghlDtvRK7gbpFN6UfLeoqwi9 4XCtUMOgnho+cZdUwYb9aMHu+cvOiK4= Received: from mail-pj1-f71.google.com (mail-pj1-f71.google.com [209.85.216.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-427-NALdZ9j-P7SuZ8xxvZxaYA-1; Wed, 09 Mar 2022 05:11:35 -0500 X-MC-Unique: NALdZ9j-P7SuZ8xxvZxaYA-1 Received: by mail-pj1-f71.google.com with SMTP id e14-20020a17090a684e00b001bf09ac2385so1300960pjm.1 for ; Wed, 09 Mar 2022 02:11:35 -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=Cbfb366ZkDSzxZK5jYsxwTNE/kSKHXFjtV5zW8Uhs+w=; b=xmJiswAzEXrs7kw0UpJdPLevc98isaHVL77XEvo1DHH7v3Q4K1jZBAp8pKGRtWD3+8 /scMeSNrkjMzx0i983wFrb7L26/Jv3CNGR5mpf9WgTxgGXXbKjq6565Q+yCiHQyD46f3 9ai7TmTjp93mhNfWWXmVQ3ldWgJYKZB/h9EAnQMU3a2VUzgwLEKOxc4otzeHvj0EVgwl zI/FBoK7LIrwyjsUi44Es7fnBfVCvoRydPZWB0MABulAa5aT9YAGeG2MoYI9ZfsWcDPv /jNA72s8NoX98lPKQRem0+JOSsfdnPXTOtZ2qtsgnTQWtqZhNur9MuvIJJQ3D5PKZ2pJ pcVQ== X-Gm-Message-State: AOAM533qTvZ9evuL2Uj3fvowGL4/b3S0/0Gi0ToXXyfchT8+FA35evtP Zc1Y+ytPoyXsNQDNLQuHpYnbY8RyNxbwKlnbLQTQ1qIYVp8d63aTts7f1OnVLXPwygstzZktkNp NZ+g5Vcr2BdSJPVRvaE0kZ/+NvzFWhSn2zEczxJYJ2AdXdmptAMAXlT1ogoZ9NgBRB3qO/MM= X-Received: by 2002:a05:6a00:2402:b0:4e1:3df2:5373 with SMTP id z2-20020a056a00240200b004e13df25373mr22489189pfh.40.1646820693961; Wed, 09 Mar 2022 02:11:33 -0800 (PST) X-Google-Smtp-Source: ABdhPJxmbXGZ+9ncuZD1NDPes+76iDkr13m8C2jdbHJQ7FK7zBuFf9uHKe8neY2OK3NHbv+P44M5gQ== X-Received: by 2002:a05:6a00:2402:b0:4e1:3df2:5373 with SMTP id z2-20020a056a00240200b004e13df25373mr22489148pfh.40.1646820693553; Wed, 09 Mar 2022 02:11:33 -0800 (PST) Received: from [10.72.13.171] ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id b16-20020a056a00115000b004f6ff260c9esm2181671pfm.207.2022.03.09.02.11.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 09 Mar 2022 02:11:31 -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> From: Xiubo Li Message-ID: <84fc2bde-2fe8-ec78-1145-2cc010259f38@redhat.com> Date: Wed, 9 Mar 2022 18:11:25 +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: <87v8wn78jq.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 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) ? > Reading the documentation in the CEPH_NOHASH_NAME_MAX definition > it seems to be 252. And in that case we need to limit the names length > even further. > >> But for none fscrypt case, we must limit the max len to NAME_MAX - 2 * >> sizeof('_') - sizeof() == 255 - 2 - 13 == 240. So fixing this in >> MDS side makes sense IMO. > Yeah, I suppose this makes sense. I can send out a PR soon with this, and > try to document it somewhere. But it may make sense to merge both PRs at > the same time and *backport* them to older releases. Yeah, make sense. - Xiubo > Cheers,