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 6AD27C4167B for ; Wed, 6 Dec 2023 09:11:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346824AbjLFJLV (ORCPT ); Wed, 6 Dec 2023 04:11:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346716AbjLFJLL (ORCPT ); Wed, 6 Dec 2023 04:11:11 -0500 Received: from out30-124.freemail.mail.aliyun.com (out30-124.freemail.mail.aliyun.com [115.124.30.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F31FF11F for ; Wed, 6 Dec 2023 01:11:16 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045192;MF=hsiangkao@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0VxxSRQH_1701853874; Received: from e69b19392.et15sqa.tbsite.net(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0VxxSRQH_1701853874) by smtp.aliyun-inc.com; Wed, 06 Dec 2023 17:11:14 +0800 From: Gao Xiang To: linux-erofs@lists.ozlabs.org Cc: LKML , dhavale@google.com, Gao Xiang Subject: [PATCH 3/5] erofs: fix up compacted indexes for block size < 4096 Date: Wed, 6 Dec 2023 17:10:55 +0800 Message-Id: <20231206091057.87027-4-hsiangkao@linux.alibaba.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20231206091057.87027-1-hsiangkao@linux.alibaba.com> References: <20231206091057.87027-1-hsiangkao@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Previously, the block size always equaled to PAGE_SIZE, therefore `lclusterbits` couldn't be less than 12. Since sub-page compressed blocks are now considered, `lobits` for a lcluster in each pack cannot always be `lclusterbits` as before. Otherwise, there is no enough room for the special value `Z_EROFS_LI_D0_CBLKCNT`. To support smaller block sizes, `lobits` for each compacted lcluster is now calculated as: lobits = max(lclusterbits, ilog2(Z_EROFS_LI_D0_CBLKCNT) + 1) Signed-off-by: Gao Xiang --- fs/erofs/zmap.c | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-) diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c index 7b55111fd533..9753875e41cb 100644 --- a/fs/erofs/zmap.c +++ b/fs/erofs/zmap.c @@ -82,29 +82,26 @@ static int z_erofs_load_full_lcluster(struct z_erofs_maprecorder *m, } static unsigned int decode_compactedbits(unsigned int lobits, - unsigned int lomask, u8 *in, unsigned int pos, u8 *type) { const unsigned int v = get_unaligned_le32(in + pos / 8) >> (pos & 7); - const unsigned int lo = v & lomask; + const unsigned int lo = v & ((1 << lobits) - 1); *type = (v >> lobits) & 3; return lo; } -static int get_compacted_la_distance(unsigned int lclusterbits, +static int get_compacted_la_distance(unsigned int lobits, unsigned int encodebits, unsigned int vcnt, u8 *in, int i) { - const unsigned int lomask = (1 << lclusterbits) - 1; unsigned int lo, d1 = 0; u8 type; DBG_BUGON(i >= vcnt); do { - lo = decode_compactedbits(lclusterbits, lomask, - in, encodebits * i, &type); + lo = decode_compactedbits(lobits, in, encodebits * i, &type); if (type != Z_EROFS_LCLUSTER_TYPE_NONHEAD) return d1; @@ -123,15 +120,14 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, { struct erofs_inode *const vi = EROFS_I(m->inode); const unsigned int lclusterbits = vi->z_logical_clusterbits; - const unsigned int lomask = (1 << lclusterbits) - 1; - unsigned int vcnt, base, lo, encodebits, nblk, eofs; + unsigned int vcnt, base, lo, lobits, encodebits, nblk, eofs; int i; u8 *in, type; bool big_pcluster; if (1 << amortizedshift == 4 && lclusterbits <= 14) vcnt = 2; - else if (1 << amortizedshift == 2 && lclusterbits == 12) + else if (1 << amortizedshift == 2 && lclusterbits <= 12) vcnt = 16; else return -EOPNOTSUPP; @@ -140,6 +136,7 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, m->nextpackoff = round_down(pos, vcnt << amortizedshift) + (vcnt << amortizedshift); big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1; + lobits = max(lclusterbits, ilog2(Z_EROFS_LI_D0_CBLKCNT) + 1U); encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt; eofs = erofs_blkoff(m->inode->i_sb, pos); base = round_down(eofs, vcnt << amortizedshift); @@ -147,15 +144,14 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, i = (eofs - base) >> amortizedshift; - lo = decode_compactedbits(lclusterbits, lomask, - in, encodebits * i, &type); + lo = decode_compactedbits(lobits, in, encodebits * i, &type); m->type = type; if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) { m->clusterofs = 1 << lclusterbits; /* figure out lookahead_distance: delta[1] if needed */ if (lookahead) - m->delta[1] = get_compacted_la_distance(lclusterbits, + m->delta[1] = get_compacted_la_distance(lobits, encodebits, vcnt, in, i); if (lo & Z_EROFS_LI_D0_CBLKCNT) { if (!big_pcluster) { @@ -174,8 +170,8 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, * of which lo saves delta[1] rather than delta[0]. * Hence, get delta[0] by the previous lcluster indirectly. */ - lo = decode_compactedbits(lclusterbits, lomask, - in, encodebits * (i - 1), &type); + lo = decode_compactedbits(lobits, in, + encodebits * (i - 1), &type); if (type != Z_EROFS_LCLUSTER_TYPE_NONHEAD) lo = 0; else if (lo & Z_EROFS_LI_D0_CBLKCNT) @@ -190,8 +186,8 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, nblk = 1; while (i > 0) { --i; - lo = decode_compactedbits(lclusterbits, lomask, - in, encodebits * i, &type); + lo = decode_compactedbits(lobits, in, + encodebits * i, &type); if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) i -= lo; @@ -202,8 +198,8 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m, nblk = 0; while (i > 0) { --i; - lo = decode_compactedbits(lclusterbits, lomask, - in, encodebits * i, &type); + lo = decode_compactedbits(lobits, in, + encodebits * i, &type); if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) { if (lo & Z_EROFS_LI_D0_CBLKCNT) { --i; -- 2.39.3