From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-111.freemail.mail.aliyun.com (out30-111.freemail.mail.aliyun.com [115.124.30.111]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 37C9B823DD for ; Fri, 13 Mar 2026 04:53:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.111 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773377619; cv=none; b=MEB4gPymnWPlLDLry3dISBsu20+9pep8PVj40rWw9hVng4GDKg29XtGfM0X1fj03N+SMS9ZkrtnsN/jsxYALPBVny4HOIJFriDnZp6jaW6kSoY6K4phcuzqFsgStecWM1GeWQIFZicwP6bwMP4ZjiVu+AaFzzBGSeb9h8FJ8miQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773377619; c=relaxed/simple; bh=6XeXD+RhgTV9V7sBumkRFf3EqTisoM8lihu9ChvVmG8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ETAOIhlCfrCPzgd/cy1srtUkPNFflb0jb//eYggnI6+8EXh8JJIz8CjupGziz15fPfrdfeFUSdIkgVvheihLz1v9cZXCPQYh7pF8bhxGBoDPcpYIN1Ny+SJhNkrHoCY8erHtIGNk1/WTJXsMTtdjSw59uoij49s9/+nWVBuL684= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=WkL4f4k8; arc=none smtp.client-ip=115.124.30.111 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="WkL4f4k8" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1773377613; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=Mu427i48vl+bXTMeJv1FaKW6evZNat+ldY8A5kb3/Xc=; b=WkL4f4k8aD/quoKinGao7KB5o+h46BMn4VQt1vtlRTtM4kn139vpno9EQlOKH4eNGj2Ucz24DDDlptPfR+BZa4SXatpO1L5BvsYA7awk++FHC7KJneMe7zdESuzSwGwbYj8oldBuPWWdHgINgtNn/ZutKHAPyP6Q8ae9HWycv2E= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033032089153;MF=joseph.qi@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0X-r0yhF_1773377612; Received: from 30.221.129.56(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0X-r0yhF_1773377612 cluster:ay36) by smtp.aliyun-inc.com; Fri, 13 Mar 2026 12:53:33 +0800 Message-ID: <488ccee8-f197-4326-aca4-4466003aed3e@linux.alibaba.com> Date: Fri, 13 Mar 2026 12:53:32 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/1] ocfs2: split transactions in dio completion to avoid credit exhaustion To: Heming Zhao Cc: ocfs2-devel@lists.linux.dev, linux-kernel@vger.kernel.org, Jan Kara References: <20260312162725.15523-1-heming.zhao@suse.com> <20260312162725.15523-2-heming.zhao@suse.com> From: Joseph Qi In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/13/26 11:17 AM, Heming Zhao wrote: > On Fri, Mar 13, 2026 at 10:04:11AM +0800, Joseph Qi wrote: >> Almost looks fine, minor updates below. >> >> On 3/13/26 12:27 AM, Heming Zhao wrote: >>> During ocfs2 dio operations, JBD2 may report warnings via following call trace: >>> ocfs2_dio_end_io_write >>> ocfs2_mark_extent_written >>> ocfs2_change_extent_flag >>> ocfs2_split_extent >>> ocfs2_try_to_merge_extent >>> ocfs2_extend_rotate_transaction >>> ocfs2_extend_trans >>> jbd2__journal_restart >>> start_this_handle >>> output: JBD2: kworker/6:2 wants too many credits credits:5450 rsv_credits:0 max:5449 >>> >>> To prevent exceeding the credits limit, modify ocfs2_dio_end_io_write() to >>> handle each extent in a separate transaction. >>> >>> Additionally, relocate ocfs2_del_inode_from_orphan(). The orphan inode should >>> only be removed from the orphan list after the extent tree update is complete. >>> this ensures that if a crash occurs in the middle of extent tree updates, we >>> won't leave stale blocks beyond EOF. >>> >>> This patch also removes the only call to ocfs2_assure_trans_credits(), which >>> was introduced by commit be346c1a6eeb ("ocfs2: fix DIO failure due to >>> insufficient transaction credits"). >>> >>> Finally, thanks to Jans for providing the bug fix prototype and suggestions. >>> >>> Suggested-by: Jan Kara >>> Signed-off-by: Heming Zhao >>> --- >>> fs/ocfs2/aops.c | 58 ++++++++++++++++++++++++------------------------- >>> 1 file changed, 29 insertions(+), 29 deletions(-) >>> >>> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c >>> index 09146b43d1f0..91997b330d39 100644 >>> --- a/fs/ocfs2/aops.c >>> +++ b/fs/ocfs2/aops.c >>> @@ -2294,18 +2294,6 @@ static int ocfs2_dio_end_io_write(struct inode *inode, >>> goto out; >>> } >>> >>> - /* Delete orphan before acquire i_rwsem. */ >>> - if (dwc->dw_orphaned) { >>> - BUG_ON(dwc->dw_writer_pid != task_pid_nr(current)); >>> - >>> - end = end > i_size_read(inode) ? end : 0; >>> - >>> - ret = ocfs2_del_inode_from_orphan(osb, inode, di_bh, >>> - !!end, end); >>> - if (ret < 0) >>> - mlog_errno(ret); >>> - } >>> - >>> down_write(&oi->ip_alloc_sem); >>> di = (struct ocfs2_dinode *)di_bh->b_data; >>> >>> @@ -2326,44 +2314,56 @@ static int ocfs2_dio_end_io_write(struct inode *inode, >>> >>> credits = ocfs2_calc_extend_credits(inode->i_sb, &di->id2.i_list); >>> >>> - handle = ocfs2_start_trans(osb, credits); >>> - if (IS_ERR(handle)) { >>> - ret = PTR_ERR(handle); >>> - mlog_errno(ret); >>> - goto unlock; >>> - } >>> - ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh, >>> - OCFS2_JOURNAL_ACCESS_WRITE); >>> - if (ret) { >>> - mlog_errno(ret); >>> - goto commit; >>> - } >>> - >>> list_for_each_entry(ue, &dwc->dw_zero_list, ue_node) { >>> - ret = ocfs2_assure_trans_credits(handle, credits); >>> - if (ret < 0) { >>> + handle = ocfs2_start_trans(osb, credits); >>> + if (IS_ERR(handle)) { >>> + ret = PTR_ERR(handle); >>> mlog_errno(ret); >>> break; >> >> I'd rather goto unlock directly without update i_size in case error. > > agree >> >>> } >>> + ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh, >>> + OCFS2_JOURNAL_ACCESS_WRITE); >>> + if (ret) { >>> + mlog_errno(ret); >>> + ocfs2_commit_trans(osb, handle); >>> + break; >> >> Ditto. > > agree >> >>> + } >>> ret = ocfs2_mark_extent_written(inode, &et, handle, >>> ue->ue_cpos, 1, >>> ue->ue_phys, >>> meta_ac, &dealloc); >>> if (ret < 0) { >>> mlog_errno(ret); >>> + ocfs2_commit_trans(osb, handle); >>> break; >> >> Ditto. > > The existing code still updates i_size even if ocfs2_mark_extent_written() > returns an error. I am not certain whether updating i_size in this case is > correct, but I prefer to maintain the original logic for now. > Does that seem reasonable to you? > Since it returns 0 for unwritten extents, it looks fine. >> BTW, we can move ocfs2_commit_trans() rightly after ocfs2_mark_extent_written() >> to save the extra call in case error. > > agree > > I ran a DIO test using 64MB chunk size (e.g.: fio --bs=64M), the dwc->dw_zero_count > is about 12107 ~ 12457. > Regarding the transaction splitting in the unwritten handling loop: this patch > introduces a minor performance regression. I would like to merge some of the > transaction calls. e.g.: by starting a new transaction every 100 or 200 iterations. > What do you think of this approach? > Seems we can limit max credit for a single transaction here? If exceeds, restart a new one. Joseph, Thanks