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 X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42482C433FF for ; Mon, 29 Jul 2019 05:54:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E19642075B for ; Mon, 29 Jul 2019 05:54:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564379699; bh=Es0XHxeZvLEv07xBP9nni5sHh8xrD51dZ25CaXeHaIU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=cLjNqGHe68lGtnFVd7/JY6KCMmrFOxQylog6VsGhjCbxtfJgfkqoJLvkQmG1s+Yjo MRAh/oIDSup85ssNtgAzpuU+tMOn9uqJymYck9Xm0efJhr3LusOenhlAjSD+xJPab3 96L0ryaiXNDiTY953vmGyTlnQ3QvGuCcXkkGIqj0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726835AbfG2Fy5 (ORCPT ); Mon, 29 Jul 2019 01:54:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:38298 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725988AbfG2Fy5 (ORCPT ); Mon, 29 Jul 2019 01:54:57 -0400 Received: from localhost (c-98-234-77-170.hsd1.ca.comcast.net [98.234.77.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3ADBA20659; Mon, 29 Jul 2019 05:54:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564379695; bh=Es0XHxeZvLEv07xBP9nni5sHh8xrD51dZ25CaXeHaIU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hU1kuFnQV6yHMT39IlH8+xC7EBz07nbhhziXHh3iGWdGalxEF5niCbLeS8UbI0eC7 PasfGwGXL356HtO/aaAAu4lJWvvhUVhsHkSFipovDkltkOhUt10y9W7AXvpk6+Caw/ QFubjvaLIG4rTZO12dR+m+wPiD4dL+qMEpcgp3rA= Date: Sun, 28 Jul 2019 22:54:54 -0700 From: Jaegeuk Kim To: Chao Yu Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH v2] f2fs: fix to read source block before invalidating it Message-ID: <20190729055454.GC94090@jaegeuk-macbookpro.roam.corp.google.com> References: <20190718013718.70335-1-jaegeuk@kernel.org> <20190718031214.GA78336@jaegeuk-macbookpro.roam.corp.google.com> <19a25101-da74-de98-6ca4-a9fd9fa09ef2@huawei.com> <20190718040005.GA81995@jaegeuk-macbookpro.roam.corp.google.com> <91dbfa33-cda0-e6e7-d62f-6604939142d4@huawei.com> <20190723012721.GA60134@jaegeuk-macbookpro.roam.corp.google.com> <45a9f47b-337c-527c-420d-b29e77a8ed22@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45a9f47b-337c-527c-420d-b29e77a8ed22@huawei.com> User-Agent: Mutt/1.8.2 (2017-04-18) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/23, Chao Yu wrote: > On 2019/7/23 9:27, Jaegeuk Kim wrote: > > On 07/18, Chao Yu wrote: > >> On 2019/7/18 12:00, Jaegeuk Kim wrote: > >>> On 07/18, Chao Yu wrote: > >>>> On 2019/7/18 11:12, Jaegeuk Kim wrote: > >>>>> f2fs_allocate_data_block() invalidates old block address and enable new block > >>>>> address. Then, if we try to read old block by f2fs_submit_page_bio(), it will > >>>>> give WARN due to reading invalid blocks. > >>>>> > >>>>> Let's make the order sanely back. > >>>> > >>>> Hmm.. to avoid WARM, we may suffer one more memcpy, I suspect this can reduce > >>>> online resize or foreground gc ioctl performance... > >>> > >>> I worried about performance tho, more concern came to me that there may exist a > >>> chance that other thread can allocate and write something in old block address. > >> > >> Me too, however, previous invalid block address should be reused after a > >> checkpoint, and checkpoint should have invalidated meta cache already, so there > >> shouldn't be any race here. > > > > I think SSR can reuse that before checkpoint. > > Yes, I should have considered that when I introduced readahead feature for > migration of block, we've kept invalidating meta page cache in old block address > whenever the block address is not valid. > > quoted from ("f2fs: readahead encrypted block during GC") > > "Note that for OPU, truncation, deletion, we need to invalid meta > page after we invalid old block address, to make sure we won't load > invalid data from target meta page during encrypted block migration." > > But to avoid potential issue, how about just enable meta page cache during GC? > that is saying we should truncate all valid meta cache after one section has > been moved. We may need to invalidate metapage when writing new data, which looks like different issue. > > One more concern is whether below case exists during SSR? > - write 4k to fileA; > - fsync fileA, 4k data is writebacked to lbaA; > - write 4k to fileA; > - kworker flushs 4k to lbaB; dnode contain lbaB didn't be persisted yet; > - write 4k to fileB; > - kworker flush 4k to lbaA due to SSR; > - SPOR -> dnode with lbaA will be recovered, however lbaA contains fileB's data.. Yes, it seems that's possible. We may need to keep another bitmap to record all the block allocation? > > Thanks, > > > > >> > >> /* > >> * invalidate intermediate page cache borrowed from meta inode > >> * which are used for migration of encrypted inode's blocks. > >> */ > >> if (f2fs_sb_has_encrypt(sbi)) > >> invalidate_mapping_pages(META_MAPPING(sbi), > >> MAIN_BLKADDR(sbi), MAX_BLKADDR(sbi) - 1); > >> > >> Thanks, > >> > >>> > >>>> > >>>> Can we just relief to use DATA_GENERIC_ENHANCE_READ for this case...? > >>> > >>> We need to keep consistency for this api. > >>> > >>> Thanks, > >>> > >>>> > >>>>> > >>>>> Signed-off-by: Jaegeuk Kim > >>>> > >>>> Except performance, I'm okay with this change. > >>>> > >>>> Reviewed-by: Chao Yu > >>>> > >>>> Thanks, > >>>> > >>>>> --- > >>>>> v2: > >>>>> I was fixing the comments. :) > >>>>> > >>>>> fs/f2fs/gc.c | 70 +++++++++++++++++++++++++--------------------------- > >>>>> 1 file changed, 34 insertions(+), 36 deletions(-) > >>>>> > >>>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > >>>>> index 6691f526fa40..8974672db78f 100644 > >>>>> --- a/fs/f2fs/gc.c > >>>>> +++ b/fs/f2fs/gc.c > >>>>> @@ -796,6 +796,29 @@ static int move_data_block(struct inode *inode, block_t bidx, > >>>>> if (lfs_mode) > >>>>> down_write(&fio.sbi->io_order_lock); > >>>>> > >>>>> + mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi), > >>>>> + fio.old_blkaddr, false); > >>>>> + if (!mpage) > >>>>> + goto up_out; > >>>>> + > >>>>> + fio.encrypted_page = mpage; > >>>>> + > >>>>> + /* read source block in mpage */ > >>>>> + if (!PageUptodate(mpage)) { > >>>>> + err = f2fs_submit_page_bio(&fio); > >>>>> + if (err) { > >>>>> + f2fs_put_page(mpage, 1); > >>>>> + goto up_out; > >>>>> + } > >>>>> + lock_page(mpage); > >>>>> + if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) || > >>>>> + !PageUptodate(mpage))) { > >>>>> + err = -EIO; > >>>>> + f2fs_put_page(mpage, 1); > >>>>> + goto up_out; > >>>>> + } > >>>>> + } > >>>>> + > >>>>> f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr, > >>>>> &sum, CURSEG_COLD_DATA, NULL, false); > >>>>> > >>>>> @@ -803,44 +826,18 @@ static int move_data_block(struct inode *inode, block_t bidx, > >>>>> newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS); > >>>>> if (!fio.encrypted_page) { > >>>>> err = -ENOMEM; > >>>>> - goto recover_block; > >>>>> - } > >>>>> - > >>>>> - mpage = f2fs_pagecache_get_page(META_MAPPING(fio.sbi), > >>>>> - fio.old_blkaddr, FGP_LOCK, GFP_NOFS); > >>>>> - if (mpage) { > >>>>> - bool updated = false; > >>>>> - > >>>>> - if (PageUptodate(mpage)) { > >>>>> - memcpy(page_address(fio.encrypted_page), > >>>>> - page_address(mpage), PAGE_SIZE); > >>>>> - updated = true; > >>>>> - } > >>>>> f2fs_put_page(mpage, 1); > >>>>> - invalidate_mapping_pages(META_MAPPING(fio.sbi), > >>>>> - fio.old_blkaddr, fio.old_blkaddr); > >>>>> - if (updated) > >>>>> - goto write_page; > >>>>> - } > >>>>> - > >>>>> - err = f2fs_submit_page_bio(&fio); > >>>>> - if (err) > >>>>> - goto put_page_out; > >>>>> - > >>>>> - /* write page */ > >>>>> - lock_page(fio.encrypted_page); > >>>>> - > >>>>> - if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) { > >>>>> - err = -EIO; > >>>>> - goto put_page_out; > >>>>> - } > >>>>> - if (unlikely(!PageUptodate(fio.encrypted_page))) { > >>>>> - err = -EIO; > >>>>> - goto put_page_out; > >>>>> + goto recover_block; > >>>>> } > >>>>> > >>>>> -write_page: > >>>>> + /* write target block */ > >>>>> f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true); > >>>>> + memcpy(page_address(fio.encrypted_page), > >>>>> + page_address(mpage), PAGE_SIZE); > >>>>> + f2fs_put_page(mpage, 1); > >>>>> + invalidate_mapping_pages(META_MAPPING(fio.sbi), > >>>>> + fio.old_blkaddr, fio.old_blkaddr); > >>>>> + > >>>>> set_page_dirty(fio.encrypted_page); > >>>>> if (clear_page_dirty_for_io(fio.encrypted_page)) > >>>>> dec_page_count(fio.sbi, F2FS_DIRTY_META); > >>>>> @@ -871,11 +868,12 @@ static int move_data_block(struct inode *inode, block_t bidx, > >>>>> put_page_out: > >>>>> f2fs_put_page(fio.encrypted_page, 1); > >>>>> recover_block: > >>>>> - if (lfs_mode) > >>>>> - up_write(&fio.sbi->io_order_lock); > >>>>> if (err) > >>>>> f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr, > >>>>> true, true); > >>>>> +up_out: > >>>>> + if (lfs_mode) > >>>>> + up_write(&fio.sbi->io_order_lock); > >>>>> put_out: > >>>>> f2fs_put_dnode(&dn); > >>>>> out: > >>>>> > >>>> > >>>> > >>>> _______________________________________________ > >>>> Linux-f2fs-devel mailing list > >>>> Linux-f2fs-devel@lists.sourceforge.net > >>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > >>> . > >>> > > . > >