From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (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 C99E818FDAF; Sat, 29 Nov 2025 01:36:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764380174; cv=none; b=bBUGh5YLwiqrbDo8hWOKPJtEFh+M6eD0yHxxUmlCSwmdOeHas/YlQT3FmX75bacGnTmjRoVfBXCpa7YWE1DhH8PQoFaO4pr+zrsNHIeIMlD6wQuxtVZpRk5GG08lBqu/sFGu3shJRB6kq1VmXn5BNgnBi79BuURTmiHs7HUBsm4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764380174; c=relaxed/simple; bh=JNGqFiRS28H3+0kZUOEA8ypYM8buy6tlWlVadSlYe+o=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=IhtEu7+aD0oURYr99ZWfvHTtbQzLD0UU2OVjFx7n0yuXjF7YbAe8OpzlqTmZKpdBfvNWKJd//NYJ3CfaK/4DsOg07e2VB/YOczuZXN9JKliLCCAdp6uauumAJeTpBkM+VWMGqvOIXNYbrmEAIb/KqHPEPqKqYiQ2k9C8xVZ/Nws= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.93.142]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4dJCR25Mh7zKHLtb; Sat, 29 Nov 2025 09:35:26 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.75]) by mail.maildlp.com (Postfix) with ESMTP id 5A5661A07BB; Sat, 29 Nov 2025 09:36:09 +0800 (CST) Received: from [10.174.178.152] (unknown [10.174.178.152]) by APP2 (Coremail) with SMTP id Syh0CgBnw3kITippzPJ+CQ--.33388S3; Sat, 29 Nov 2025 09:36:09 +0800 (CST) Message-ID: Date: Sat, 29 Nov 2025 09:36:08 +0800 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 07/13] ext4: drop extent cache before splitting extent To: Ojaswin Mujoo Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, jack@suse.cz, yi.zhang@huawei.com, yizhang089@gmail.com, libaokun1@huawei.com, yangerkun@huawei.com References: <20251121060811.1685783-1-yi.zhang@huaweicloud.com> <20251121060811.1685783-8-yi.zhang@huaweicloud.com> <8680efcd-dc84-4b4e-ab75-216de959ec88@huaweicloud.com> Content-Language: en-US From: Zhang Yi In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CM-TRANSID:Syh0CgBnw3kITippzPJ+CQ--.33388S3 X-Coremail-Antispam: 1UD129KBjvJXoW7tFyDGFyDGw4xGw43tryxZrb_yoW8Wry3pr W3GF18KrW8Aw1jk3s2vw4jqr92ka4rKr47ury5Kw1YyF9FgryYgF17ta1rCFyFgr48Xw1a vF48K34fuasxC3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUv0b4IE77IF4wAFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x 0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG 6I80ewAv7VC0I7IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFV Cjc4AY6r1j6r4UM4x0Y48IcVAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxkF7I0En4kS 14v26r1q6r43MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I 8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8 ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x 0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_ Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IUb mii3UUUUU== X-CM-SenderInfo: d1lo6xhdqjqx5xdzvxpfor3voofrz/ On 11/28/2025 4:16 PM, Ojaswin Mujoo wrote: > On Thu, Nov 27, 2025 at 03:27:26PM +0800, Zhang Yi wrote: >> On 11/26/2025 8:24 PM, Ojaswin Mujoo wrote: >>> On Fri, Nov 21, 2025 at 02:08:05PM +0800, Zhang Yi wrote: >>>> From: Zhang Yi >>>> [...] >>>> >>>> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c >>>> index 2b5aec3f8882..9bb80af4b5cf 100644 >>>> --- a/fs/ext4/extents.c >>>> +++ b/fs/ext4/extents.c >>>> @@ -3367,6 +3367,12 @@ static struct ext4_ext_path *ext4_split_extent(handle_t *handle, >>>> ee_len = ext4_ext_get_actual_len(ex); >>>> unwritten = ext4_ext_is_unwritten(ex); >>>> >>>> + /* >>>> + * Drop extent cache to prevent stale unwritten extents remaining >>>> + * after zeroing out. >>>> + */ >>>> + ext4_es_remove_extent(inode, ee_block, ee_len); >>>> + > > Okay this makes sense, there are many different combinations of how the > on disk extents might turn out and if will become complicated to keep > the es in sync to those, so this seems simpler. > > There might be a small performance penalty of dropping the es here tho > but idk if it's anything measurable. As a middle ground do you think it > makes more sense to drop the es cache in ext4_split_extent_at() instead, > when we know we are about to go for zeroout. Since the default non > zeroout path seems to be okay? > > Regards, > ojaswin > > Yes, this makes sense to me! I will move it to ext4_split_extent_at() in my next iteration. Thanks, Yi. > >>>> /* Do not cache extents that are in the process of being modified. */ >>>> flags |= EXT4_EX_NOCACHE; >>>> >>>> -- >>>> 2.46.1 >>>> >>