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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 27380C433F5 for ; Tue, 31 May 2022 09:51:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 66C886B0072; Tue, 31 May 2022 05:51:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6232E6B0073; Tue, 31 May 2022 05:51:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 504C96B0074; Tue, 31 May 2022 05:51:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 42F176B0072 for ; Tue, 31 May 2022 05:51:39 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 13CFD34A42 for ; Tue, 31 May 2022 09:51:39 +0000 (UTC) X-FDA: 79525571118.01.B428FF4 Received: from mail-ua1-f47.google.com (mail-ua1-f47.google.com [209.85.222.47]) by imf24.hostedemail.com (Postfix) with ESMTP id C640118004D for ; Tue, 31 May 2022 09:51:23 +0000 (UTC) Received: by mail-ua1-f47.google.com with SMTP id r9so343353uaf.13 for ; Tue, 31 May 2022 02:51:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=MpCPQJh9DbmIe7accXEFW1MsdAJOpJw3XILL74h1u8M=; b=MFZ8iyL11Ahdehuvsatbb06YXUeBsjmmb4uQxxiEae3fLZHKfCTK4VDf6cZQPHCaV8 tkVMOXgiraMtFgSfjb5LW9Nzzpcy22Z/UEO2ruWxUhPAsmAvPmg8rH6sUbIVNB3fUKzW D3P1gtyIXJNTmrDoKPsRwYasWaR0V08emUExg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=MpCPQJh9DbmIe7accXEFW1MsdAJOpJw3XILL74h1u8M=; b=SvpPcOt2WjRa8yTqx5I/1CrBXO6lxpn2oymwAzPIH73cZM6XfqTRA73zPRpkyX1wOR f/4lap+Acrk4qDFZbq9Z3dliMlyW2jbetv1MaUBmnvfZkiEhwMLxCXKWt2WOhapwiNZG 5cMd+n144IyW1MkXzS9fSUEN193nkiFWZNWCC4Mw4qQva8bEo6eOlB3Gn88ayZt31ILv BYf29aL7vXziyD+t5TR91pkJ8Fh//pThuXx4zHKxi1dylfYpH3virGAMt+0yLwSXj2J2 MzyDTapjaWe1AhFZT9NpKXOY0OX/TWXux9Jtn/79xQj+QzxXMrI5HKi2Af3xpAxr3XyB PbUg== X-Gm-Message-State: AOAM531sIzEAthIkRvy91On0NIehXNjc9jRNhrK5bVWgGGxEEboQH9mq rISSe7WDHACx/UeDlrEeduGZyAYav0A3AlF37KBjQQ== X-Google-Smtp-Source: ABdhPJykLd5RBbYQLFNRj8qD1kI6mK6loSCqsvU5Zt6aNJlpFZyIHg+9EsfgCS83B9dFxPv55dhHgtyOoUrD/CXhMqU= X-Received: by 2002:ab0:3492:0:b0:368:b577:bfd with SMTP id c18-20020ab03492000000b00368b5770bfdmr20306664uar.110.1653990697684; Tue, 31 May 2022 02:51:37 -0700 (PDT) MIME-Version: 1.0 References: <20220523065909.883444-1-hsinyi@chromium.org> <20220523065909.883444-4-hsinyi@chromium.org> In-Reply-To: <20220523065909.883444-4-hsinyi@chromium.org> From: Hsin-Yi Wang Date: Tue, 31 May 2022 17:51:11 +0800 Message-ID: Subject: Re: [PATCH v3 3/3] squashfs: implement readahead To: Phillip Lougher , Matthew Wilcox , Xiongwei Song Cc: Zheng Liang , Zhang Yi , Hou Tao , Miao Xie , Andrew Morton , "linux-mm @ kvack . org" , "squashfs-devel @ lists . sourceforge . net" , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: oz9rm8j8goxtnjchue64rmxuhn1ktt5m X-Rspam-User: Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=MFZ8iyL1; spf=pass (imf24.hostedemail.com: domain of hsinyi@chromium.org designates 209.85.222.47 as permitted sender) smtp.mailfrom=hsinyi@chromium.org; dmarc=pass (policy=none) header.from=chromium.org X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: C640118004D X-HE-Tag: 1653990683-960861 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, May 23, 2022 at 3:00 PM Hsin-Yi Wang wrote: > > Implement readahead callback for squashfs. It will read datablocks > which cover pages in readahead request. For a few cases it will > not mark page as uptodate, including: > - file end is 0. > - zero filled blocks. > - current batch of pages isn't in the same datablock or not enough in a > datablock. > - decompressor error. > Otherwise pages will be marked as uptodate. The unhandled pages will be > updated by readpage later. > > Suggested-by: Matthew Wilcox > Signed-off-by: Hsin-Yi Wang > Reported-by: Matthew Wilcox > Reported-by: Phillip Lougher > Reported-by: Xiongwei Song > --- Kindly ping on the thread. Conversations on v2: https://patchwork.kernel.org/project/linux-mm/patch/20220517082650.2005840-4-hsinyi@chromium.org/#24869037 This version mainly addressed the error handling. Thanks > v2->v3: Add checks on > - decompressed block size. > - fill zeros if the last page is not a full page. > > v2: https://lore.kernel.org/lkml/20220517082650.2005840-4-hsinyi@chromium.org/ > v1: https://lore.kernel.org/lkml/20220516105100.1412740-3-hsinyi@chromium.org/ > --- > fs/squashfs/file.c | 91 +++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 90 insertions(+), 1 deletion(-) > > diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c > index a8e495d8eb86..c311fc685fe4 100644 > --- a/fs/squashfs/file.c > +++ b/fs/squashfs/file.c > @@ -39,6 +39,7 @@ > #include "squashfs_fs_sb.h" > #include "squashfs_fs_i.h" > #include "squashfs.h" > +#include "page_actor.h" > > /* > * Locate cache slot in range [offset, index] for specified inode. If > @@ -495,7 +496,95 @@ static int squashfs_read_folio(struct file *file, struct folio *folio) > return 0; > } > > +static void squashfs_readahead(struct readahead_control *ractl) > +{ > + struct inode *inode = ractl->mapping->host; > + struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info; > + size_t mask = (1UL << msblk->block_log) - 1; > + size_t shift = msblk->block_log - PAGE_SHIFT; > + loff_t start = readahead_pos(ractl) &~ mask; > + size_t len = readahead_length(ractl) + readahead_pos(ractl) - start; > + struct squashfs_page_actor *actor; > + unsigned int nr_pages = 0; > + struct page **pages; > + u64 block = 0; > + int bsize, res, i, index, bytes, expected; > + int file_end = i_size_read(inode) >> msblk->block_log; > + unsigned int max_pages = 1UL << shift; > + void *pageaddr; > + > + readahead_expand(ractl, start, (len | mask) + 1); > + > + if (file_end == 0) > + return; > + > + pages = kmalloc_array(max_pages, sizeof(void *), GFP_KERNEL); > + if (!pages) > + return; > + > + actor = squashfs_page_actor_init_special(pages, max_pages, 0); > + if (!actor) > + goto out; > + > + for (;;) { > + nr_pages = __readahead_batch(ractl, pages, max_pages); > + if (!nr_pages) > + break; > + > + if (readahead_pos(ractl) >= i_size_read(inode) || > + nr_pages < max_pages) > + goto skip_pages; > + > + index = pages[0]->index >> shift; > + if ((pages[nr_pages - 1]->index >> shift) != index) > + goto skip_pages; > + > + expected = index == file_end ? > + (i_size_read(inode) & (msblk->block_size - 1)) : > + msblk->block_size; > + > + bsize = read_blocklist(inode, index, &block); > + if (bsize == 0) > + goto skip_pages; > + > + res = squashfs_read_data(inode->i_sb, block, bsize, NULL, > + actor); > + > + if (res == expected) { > + /* Last page may have trailing bytes not filled */ > + bytes = res % PAGE_SIZE; > + if (bytes) { > + pageaddr = kmap_atomic(pages[nr_pages - 1]); > + memset(pageaddr + bytes, 0, PAGE_SIZE - bytes); > + kunmap_atomic(pageaddr); > + } > + > + for (i = 0; i < nr_pages; i++) > + SetPageUptodate(pages[i]); > + } > + > + for (i = 0; i < nr_pages; i++) { > + unlock_page(pages[i]); > + put_page(pages[i]); > + } > + } > + > + kfree(actor); > + kfree(pages); > + return; > + > +skip_pages: > + for (i = 0; i < nr_pages; i++) { > + unlock_page(pages[i]); > + put_page(pages[i]); > + } > + > + kfree(actor); > +out: > + kfree(pages); > +} > > const struct address_space_operations squashfs_aops = { > - .read_folio = squashfs_read_folio > + .read_folio = squashfs_read_folio, > + .readahead = squashfs_readahead > }; > -- > 2.36.1.124.g0e6072fb45-goog >