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 DBB28C433F5 for ; Wed, 9 Mar 2022 03:22:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231670AbiCIDW6 (ORCPT ); Tue, 8 Mar 2022 22:22:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231605AbiCIDW5 (ORCPT ); Tue, 8 Mar 2022 22:22:57 -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 BB5F415AF22 for ; Tue, 8 Mar 2022 19:21:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646796118; 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=3Wq4xvWxBRiCC/tuaXNwlLSiMAVLJzfGzMfCjYZ/yOM=; b=Z8EgN5jkgiAlx/rop3bIgFQim74lDLf4OF3dnADYy3oLCoid/+X+4kwhOkbymt8/62fiV4 e/iZ2Kcvf6MJbZS0HhpxDMBXZMS5SqiQxezUnmAsHPFk2CrYCgcE1pmrbrjWiFnq3zwnlt c1OHnT7mvcBQsh7q32fOCSz4s8gSpyQ= Received: from mail-pj1-f72.google.com (mail-pj1-f72.google.com [209.85.216.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-7-Uoh2vQQgPA6Sn5ikdNAUgw-1; Tue, 08 Mar 2022 22:21:57 -0500 X-MC-Unique: Uoh2vQQgPA6Sn5ikdNAUgw-1 Received: by mail-pj1-f72.google.com with SMTP id t10-20020a17090a5d8a00b001bed9556134so2917904pji.5 for ; Tue, 08 Mar 2022 19:21:57 -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=3Wq4xvWxBRiCC/tuaXNwlLSiMAVLJzfGzMfCjYZ/yOM=; b=xhFEHSmTt6pFvRmoPxEZ7r03atUM9vvs5axSK9EXEuFskHk9inOPPAh0/IzD0mVevA uNXOPrIfjtyH6b9hAoxQY88XfXEt2loO4KFBvZfQhqc8JcBBo/N4xdOnX5Yh8hyPM1G0 CJI43eDM1jtzz+GGKw0zYLA6cVWDGdMkwGHoe2vqhyT1kkzi/6s7fuS12VklKxxiblNS T9PzkPNQGnueaoRofk5+MiMMtqDK69GVYp6gA412FFF2wuPQIXNjJhWCR8ENhi8kM32n mm2bbfmt6nSPm4v8Ef2XNRU+28HZ6fPIhTsBkMoxr5fD+9IilLaQAmjwrnrtgB1Yo9Gd kGrw== X-Gm-Message-State: AOAM531eBtKTBkuizJauK0BaqdoQ9fFL33tmXFzlAj6fKv1ffNz8ST0G 9BvCROEypkzfc2BaOemWxQWvOBCj/dJhgXg30ASgeaAe+isrWGoH8GreuhEdUlB5GsXe79KfXIg ZwNRbMPVZpCwy0NvkItaEaESTVCuYM+XN+PTWFt23TEPxeb5upm0tENCaTHFc09oAf7IqHNw= X-Received: by 2002:a17:90b:17ca:b0:1bf:6188:cb5e with SMTP id me10-20020a17090b17ca00b001bf6188cb5emr8091747pjb.89.1646796116270; Tue, 08 Mar 2022 19:21:56 -0800 (PST) X-Google-Smtp-Source: ABdhPJxwG3kXMbl2f2vSkJHOxSPF2Nory8QW15OiyEb8OfPRd8w9f2jRiSPCDLatV3uEBzo7ZFzymQ== X-Received: by 2002:a17:90b:17ca:b0:1bf:6188:cb5e with SMTP id me10-20020a17090b17ca00b001bf6188cb5emr8091726pjb.89.1646796115819; Tue, 08 Mar 2022 19:21:55 -0800 (PST) Received: from [10.72.13.171] ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id g28-20020a63111c000000b00374646abc42sm493607pgl.36.2022.03.08.19.21.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Mar 2022 19:21:54 -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> From: Xiubo Li Message-ID: Date: Wed, 9 Mar 2022 11:21:48 +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: <87h788z67y.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 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. 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. - Xiubo > Cheers,