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 76FD3C433F5 for ; Wed, 16 Mar 2022 00:48:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352862AbiCPAty (ORCPT ); Tue, 15 Mar 2022 20:49:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352854AbiCPAtw (ORCPT ); Tue, 15 Mar 2022 20:49:52 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 51CCD275E9 for ; Tue, 15 Mar 2022 17:48:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1647391718; 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=3wgRCg5rHLO663AukahnIUlWXYq2JT3ybopJbTiJj1k=; b=jRMgiChy08O7GgGGRD2ZfdrVFW/SmPDp5r0z3WTpErAJ8wGdeEOLJkfGBNm0YFSHesf0oH 54yB+FOFkUgUS37niJt4pmhcfGrwRcqrh0YWCxseZBw+Krsj7qLgyz9BwJHH1umcQrSG3+ PXdyfc9ezhrZYqJytnAEoUcLyK59u4I= Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-326-D62ycw0pPy6CDoWtg1gHrA-1; Tue, 15 Mar 2022 20:48:37 -0400 X-MC-Unique: D62ycw0pPy6CDoWtg1gHrA-1 Received: by mail-pl1-f198.google.com with SMTP id w24-20020a170902a71800b001538d7b076dso343003plq.16 for ; Tue, 15 Mar 2022 17:48:37 -0700 (PDT) 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=3wgRCg5rHLO663AukahnIUlWXYq2JT3ybopJbTiJj1k=; b=BehGaEcrDYrqVme95C+DzvEbkl7cMAb1ZLdT5iq5FdJBQruMVkHiDovTMf5ytf3ASn RwdwU0JHWqvspeMrJnmGiP3z9hU/37/r7TLkfxMGgz5kx8MIW6xCwNk8DSBgECj8FEnh b+0IO65XcF0zjq8HAwnddxqmL6TpAcaIWclXLSDTnYJlBsduwSZpunCUJATmtOamDnTT +iHBYamNn3/0ALdpXIqVs2A0I04+woaUe1v57cI25x9DlBnIoNK9ge8Wf1HMG0qiXeb0 SWprUXD06a3s/CsoJAVO8lTv9cxZYPgjLtbcDTolVoheOkG+ZQn+BE8OsplVUDHU4jIp he8Q== X-Gm-Message-State: AOAM531lUFhwFLZO5kcadBumc2J6V6hrAbjH70lwAxB5fei4AgFewQoj IDobuiuKDxH/+1u3mQAf092Pu8hMU9mscmC5Psmi6E6qSR6HhdEy8BnoRM0ZCIFHU2apwXFdCdn 3CNUh/ogM9Y9qeAPTmT1eBlSN12PtTSSeTo5kFhmcTob5zuXTrizh423gjUCvjlKxQVOxurcu0A == X-Received: by 2002:a63:2d5:0:b0:380:b650:f948 with SMTP id 204-20020a6302d5000000b00380b650f948mr26319032pgc.37.1647391716086; Tue, 15 Mar 2022 17:48:36 -0700 (PDT) X-Google-Smtp-Source: ABdhPJy/EuxJR8F+CmeO2gnkczskKa4EqhaacvFTKGED45uanz3yM1nO0Aw2PqT11iclTxWX5+psYQ== X-Received: by 2002:a63:2d5:0:b0:380:b650:f948 with SMTP id 204-20020a6302d5000000b00380b650f948mr26319012pgc.37.1647391715786; Tue, 15 Mar 2022 17:48:35 -0700 (PDT) Received: from [10.72.12.110] ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id d19-20020a056a00199300b004f7b7bb0733sm327732pfl.60.2022.03.15.17.48.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 15 Mar 2022 17:48:35 -0700 (PDT) Subject: Re: [RFC PATCH v2 3/3] ceph: update documentation regarding snapshot naming limitations To: =?UTF-8?Q?Lu=c3=ads_Henriques?= , Jeff Layton , Ilya Dryomov Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org References: <20220315161959.19453-1-lhenriques@suse.de> <20220315161959.19453-4-lhenriques@suse.de> From: Xiubo Li Message-ID: Date: Wed, 16 Mar 2022 08:48:30 +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: <20220315161959.19453-4-lhenriques@suse.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/16/22 12:19 AM, Luís Henriques wrote: > Signed-off-by: Luís Henriques > --- > Documentation/filesystems/ceph.rst | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/Documentation/filesystems/ceph.rst b/Documentation/filesystems/ceph.rst > index 4942e018db85..d487cabe792d 100644 > --- a/Documentation/filesystems/ceph.rst > +++ b/Documentation/filesystems/ceph.rst > @@ -57,6 +57,16 @@ a snapshot on any subdirectory (and its nested contents) in the > system. Snapshot creation and deletion are as simple as 'mkdir > .snap/foo' and 'rmdir .snap/foo'. > > +Snapshot names have two limitations: > + > +* They can not start with an underscore ('_'), as these names are reserved > + for internal usage by the MDS. > +* They can not exceed 240 characters in size. This is because the MDS makes > + use of long snapshot names internally, which follow the format: > + `__`. Since filenames in general can't have > + more than 255 characters, and `` takes 13 characters, the long > + snapshot names can take as much as 255 - 1 - 1 - 13 = 240. > + > Ceph also provides some recursive accounting on directories for nested > files and bytes. That is, a 'getfattr -d foo' on any directory in the > system will reveal the total number of nested regular files and > LGTM. Reviewed-by: Xiubo Li