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 DC037C433F5 for ; Sun, 2 Jan 2022 07:23:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232907AbiABHXj (ORCPT ); Sun, 2 Jan 2022 02:23:39 -0500 Received: from out4436.biz.mail.alibaba.com ([47.88.44.36]:44845 "EHLO out4436.biz.mail.alibaba.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229520AbiABHXi (ORCPT ); Sun, 2 Jan 2022 02:23:38 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R271e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04357;MF=bo.liu@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0V0YVkFK_1641108201; Received: from rsjd01523.et2sqa(mailfrom:bo.liu@linux.alibaba.com fp:SMTPD_---0V0YVkFK_1641108201) by smtp.aliyun-inc.com(127.0.0.1); Sun, 02 Jan 2022 15:23:26 +0800 Date: Sun, 2 Jan 2022 15:23:21 +0800 From: Liu Bo To: Gao Xiang Cc: linux-erofs@lists.ozlabs.org, Chao Yu , LKML , Yue Hu Subject: Re: [PATCH v2 3/5] erofs: use meta buffers for super operations Message-ID: <20220102072314.GA40650@rsjd01523.et2sqa> Reply-To: bo.liu@linux.alibaba.com References: <20220102040017.51352-1-hsiangkao@linux.alibaba.com> <20220102040017.51352-4-hsiangkao@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220102040017.51352-4-hsiangkao@linux.alibaba.com> User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 02, 2022 at 12:00:15PM +0800, Gao Xiang wrote: > Get rid of old erofs_get_meta_page() within super operations by > using on-stack meta buffers in order to prepare subpage and folio > features. > > Reviewed-by: Yue Hu > Signed-off-by: Gao Xiang > --- > fs/erofs/super.c | 105 ++++++++++++----------------------------------- > 1 file changed, 26 insertions(+), 79 deletions(-) > > diff --git a/fs/erofs/super.c b/fs/erofs/super.c > index 0724ad5fd6cf..38305fa2969b 100644 > --- a/fs/erofs/super.c > +++ b/fs/erofs/super.c > @@ -2,6 +2,7 @@ > /* > * Copyright (C) 2017-2018 HUAWEI, Inc. > * https://www.huawei.com/ > + * Copyright (C) 2021, Alibaba Cloud > */ > #include > #include > @@ -124,80 +125,48 @@ static bool check_layout_compatibility(struct super_block *sb, > > #ifdef CONFIG_EROFS_FS_ZIP > /* read variable-sized metadata, offset will be aligned by 4-byte */ > -static void *erofs_read_metadata(struct super_block *sb, struct page **pagep, > +static void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf, > erofs_off_t *offset, int *lengthp) > { > - struct page *page = *pagep; > u8 *buffer, *ptr; > int len, i, cnt; > - erofs_blk_t blk; > > *offset = round_up(*offset, 4); > - blk = erofs_blknr(*offset); > + ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset), EROFS_KMAP); > + if (IS_ERR(ptr)) > + return ptr; > > - if (!page || page->index != blk) { > - if (page) { > - unlock_page(page); > - put_page(page); > - } > - page = erofs_get_meta_page(sb, blk); > - if (IS_ERR(page)) > - goto err_nullpage; > - } > - > - ptr = kmap(page); > len = le16_to_cpu(*(__le16 *)&ptr[erofs_blkoff(*offset)]); > if (!len) > len = U16_MAX + 1; > buffer = kmalloc(len, GFP_KERNEL); > - if (!buffer) { > - buffer = ERR_PTR(-ENOMEM); > - goto out; > - } > + if (!buffer) > + return ERR_PTR(-ENOMEM); > *offset += sizeof(__le16); > *lengthp = len; > > for (i = 0; i < len; i += cnt) { > cnt = min(EROFS_BLKSIZ - (int)erofs_blkoff(*offset), len - i); > - blk = erofs_blknr(*offset); > - > - if (!page || page->index != blk) { > - if (page) { > - kunmap(page); > - unlock_page(page); > - put_page(page); > - } > - page = erofs_get_meta_page(sb, blk); > - if (IS_ERR(page)) { > - kfree(buffer); > - goto err_nullpage; > - } > - ptr = kmap(page); > - } > + ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset), > + EROFS_KMAP); > + if (IS_ERR(ptr)) kfree(buffer) is missing. > + return ptr; > memcpy(buffer + i, ptr + erofs_blkoff(*offset), cnt); > *offset += cnt; > } > -out: > - kunmap(page); > - *pagep = page; > return buffer; > -err_nullpage: > - *pagep = NULL; > - return page; > } > > static int erofs_load_compr_cfgs(struct super_block *sb, > struct erofs_super_block *dsb) > { > - struct erofs_sb_info *sbi; > - struct page *page; > + struct erofs_sb_info *sbi = EROFS_SB(sb); > + struct erofs_buf buf = __EROFS_BUF_INITIALIZER; > unsigned int algs, alg; > erofs_off_t offset; > - int size, ret; > + int size, ret = 0; > > - sbi = EROFS_SB(sb); > sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs); > - > if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) { > erofs_err(sb, "try to load compressed fs with unsupported algorithms %x", > sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS); > @@ -205,21 +174,16 @@ static int erofs_load_compr_cfgs(struct super_block *sb, > } > > offset = EROFS_SUPER_OFFSET + sbi->sb_size; > - page = NULL; > alg = 0; > - ret = 0; > - > for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) { > void *data; > > if (!(algs & 1)) > continue; > > - data = erofs_read_metadata(sb, &page, &offset, &size); > - if (IS_ERR(data)) { > - ret = PTR_ERR(data); > - goto err; > - } > + data = erofs_read_metadata(sb, &buf, &offset, &size); if PTR_ERR(data) is -ENOMEM, buf needs to be put according to the current design. > + if (IS_ERR(data)) > + return PTR_ERR(data); > > switch (alg) { > case Z_EROFS_COMPRESSION_LZ4: > @@ -234,13 +198,9 @@ static int erofs_load_compr_cfgs(struct super_block *sb, > } > kfree(data); > if (ret) > - goto err; > - } > -err: > - if (page) { > - unlock_page(page); > - put_page(page); > + break; > } > + erofs_put_metabuf(&buf); > return ret; > } > #else > @@ -261,7 +221,7 @@ static int erofs_init_devices(struct super_block *sb, > struct erofs_sb_info *sbi = EROFS_SB(sb); > unsigned int ondisk_extradevs; > erofs_off_t pos; > - struct page *page = NULL; > + struct erofs_buf buf = __EROFS_BUF_INITIALIZER; > struct erofs_device_info *dif; > struct erofs_deviceslot *dis; > void *ptr; > @@ -285,22 +245,13 @@ static int erofs_init_devices(struct super_block *sb, > pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE; > down_read(&sbi->devs->rwsem); > idr_for_each_entry(&sbi->devs->tree, dif, id) { > - erofs_blk_t blk = erofs_blknr(pos); > struct block_device *bdev; > > - if (!page || page->index != blk) { > - if (page) { > - kunmap(page); > - unlock_page(page); > - put_page(page); > - } > - > - page = erofs_get_meta_page(sb, blk); > - if (IS_ERR(page)) { > - up_read(&sbi->devs->rwsem); > - return PTR_ERR(page); > - } > - ptr = kmap(page); > + ptr = erofs_read_metabuf(&buf, sb, erofs_blknr(pos), > + EROFS_KMAP); > + if (IS_ERR(ptr)) { Ditto. Thanks, liubo > + up_read(&sbi->devs->rwsem); > + return PTR_ERR(ptr); > } > dis = ptr + erofs_blkoff(pos); > > @@ -320,11 +271,7 @@ static int erofs_init_devices(struct super_block *sb, > } > err_out: > up_read(&sbi->devs->rwsem); > - if (page) { > - kunmap(page); > - unlock_page(page); > - put_page(page); > - } > + erofs_put_metabuf(&buf); > return err; > } > > -- > 2.24.4