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 81B62EB64D7 for ; Wed, 21 Jun 2023 08:32:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231325AbjFUIcU (ORCPT ); Wed, 21 Jun 2023 04:32:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59214 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229999AbjFUIcP (ORCPT ); Wed, 21 Jun 2023 04:32:15 -0400 Received: from out30-119.freemail.mail.aliyun.com (out30-119.freemail.mail.aliyun.com [115.124.30.119]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61BF110E6 for ; Wed, 21 Jun 2023 01:32:14 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045170;MF=jefflexu@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0VlfGJyV_1687336330; Received: from localhost(mailfrom:jefflexu@linux.alibaba.com fp:SMTPD_---0VlfGJyV_1687336330) by smtp.aliyun-inc.com; Wed, 21 Jun 2023 16:32:10 +0800 From: Jingbo Xu To: hsiangkao@linux.alibaba.com, chao@kernel.org, huyue2@coolpad.com, linux-erofs@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org, alexl@redhat.com Subject: [RFC 1/2] erofs: update on-disk format for xattr bloom filter Date: Wed, 21 Jun 2023 16:32:08 +0800 Message-Id: <20230621083209.116024-2-jefflexu@linux.alibaba.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20230621083209.116024-1-jefflexu@linux.alibaba.com> References: <20230621083209.116024-1-jefflexu@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The xattr bloom filter feature is going to be introduced to speed up the negative xattr lookup, e.g. system.posix_acl_[access|default] lookup when running "ls -lR" workload. The number of common used xattr (n) is approximately 8, including system.[posix_acl_access|posix_acl_default], security.[capability|selinux] and security.[SMACK64|SMACK64TRANSMUTE|SMACK64EXEC|SMACK64MMAP]. Given the number of bits of the bloom filter (m) is 32, the optimal value for the number of the hash functions (k) is 2 (ln2 * m/n = 2.7). Signed-off-by: Jingbo Xu --- fs/erofs/erofs_fs.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h index 2c7b16e340fe..9daea86cdb52 100644 --- a/fs/erofs/erofs_fs.h +++ b/fs/erofs/erofs_fs.h @@ -13,6 +13,7 @@ #define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x00000001 #define EROFS_FEATURE_COMPAT_MTIME 0x00000002 +#define EROFS_FEATURE_COMPAT_XATTR_BLOOM 0x00000003 /* * Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should @@ -200,7 +201,7 @@ struct erofs_inode_extended { * for read-only fs, no need to introduce h_refcount */ struct erofs_xattr_ibody_header { - __le32 h_reserved; + __le32 h_map; /* bloom filter, bit value 1 indicates not-present */ __u8 h_shared_count; __u8 h_reserved2[7]; __le32 h_shared_xattrs[]; /* shared xattr id array */ @@ -221,6 +222,11 @@ struct erofs_xattr_ibody_header { #define EROFS_XATTR_LONG_PREFIX 0x80 #define EROFS_XATTR_LONG_PREFIX_MASK 0x7f +#define EROFS_XATTR_BLOOM_BITS 32 +#define EROFS_XATTR_BLOOM_MASK (EROFS_XATTR_BLOOM_BITS - 1) +#define EROFS_XATTR_BLOOM_DEFAULT UINT32_MAX +#define EROFS_XATTR_BLOOM_COUNTS 2 + /* xattr entry (for both inline & shared xattrs) */ struct erofs_xattr_entry { __u8 e_name_len; /* length of name */ -- 2.19.1.6.gb485710b