From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 04654402459; Thu, 19 Mar 2026 21:26:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773955568; cv=none; b=DwLbfP4iPTS305eEuc92MnoO229hdB2o5Pzr2jyFFKh0AGglR9tH8p3lc+wNqP7wJE1KrwgicN8QJwQB8CpErd6nFihhB2gJE5lbfZqFRfRsRm+hmCwmbx57ZKvafZZv+Hp/q9f9d5ph2OkHGAvyY+DR+XnfDptJqG8LUna0/jo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773955568; c=relaxed/simple; bh=86ORD5QxZLT54WM41eJIPD/KeX+xFRSwH9SvtCoJslk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=KsRpILPChU76l2qPSeOfZaVrAXmugHEi7zwlzj2dpUUQS/BMGSgfeh3hqs3pWpJifvJ3HAJxSujzxgo4dkWwEz9VP6xBLpXb24pz9ea7IXnNTidaUG8gSP1e5Gml/x6Id6yxXv6TzagEyLdTu26SDti/K1cE9wnjcqsLFME6z7k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aDABmK1b; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aDABmK1b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77CD7C19424; Thu, 19 Mar 2026 21:26:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773955567; bh=86ORD5QxZLT54WM41eJIPD/KeX+xFRSwH9SvtCoJslk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=aDABmK1bZEEjOJaJGu3AGXNEc63v7xNPp+VXwFx0sNoB4BAzkYQQdv3JiE87x8zbq 037JI3rKIt3pJ2Q81C2xG0lJ8MXZK+8+eLj4G3/TQsrvNsfY52FVc/nq+7zPlWgrZS iP62Ni65CYSaSdAIpkHyoWTu+yorjxVlMwcb/Zc8khP4u9R9yas01i/dh82EhgIe2J L7K7Het4cwqqp4SuhHHnHAl/b6mX3Ou7A/K42bG4qDT6nT/oJi7e6yzscX0Ov8k0OU SuwGkOkaXG+MhuP7FWlMS+fsqKwNMk+k4pa11oLG6rY1LrgO6/GCl+sNpsHtrdYXCS f6uit7rGkk3Ug== Message-ID: <1f1dafa7-54c7-4eae-a19e-5ec1be391079@kernel.org> Date: Thu, 19 Mar 2026 22:26:03 +0100 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/1] writeback: don't block sync(2) for filesystems with no data integrity guarantees To: Joanne Koong , brauner@kernel.org Cc: linux-fsdevel@vger.kernel.org, jack@suse.cz, miklos@szeredi.hu, therealgraysky@proton.me, linux-pm@vger.kernel.org, stable@vger.kernel.org References: <20260319194540.3463371-1-joannelkoong@gmail.com> <20260319194540.3463371-2-joannelkoong@gmail.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/19/26 20:45, Joanne Koong wrote: > Add a SB_I_NO_DATA_INTEGRITY superblock flag for filesystems that cannot > guarantee data persistence on sync (eg fuse). For superblocks with this > flag set, sync(2) kicks off writeback of dirty inodes but does not wait > for the flusher threads to complete the writeback. > > This replaces the per-inode AS_NO_DATA_INTEGRITY mapping flag added in > commit f9a49aa302a0 ("fs/writeback: skip AS_NO_DATA_INTEGRITY mappings > in wait_sb_inodes()"). The flag belongs at the superblock level because > data integrity is a filesystem-wide property, not a per-inode one. > Having this flag at the superblock level allows us to skip the logic in > sync_inodes_sb() entirely, rather than iterating every dirty inode in > wait_sb_inodes() only to skip each inode individually. Makes sense to me. [...] > if (sb->s_user_ns != &init_user_ns) > sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER; > sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION); > diff --git a/fs/sync.c b/fs/sync.c > index 942a60cfedfb..aedbf723830a 100644 > --- a/fs/sync.c > +++ b/fs/sync.c > @@ -73,7 +73,12 @@ EXPORT_SYMBOL(sync_filesystem); > > static void sync_inodes_one_sb(struct super_block *sb, void *arg) > { > - if (!sb_rdonly(sb)) > + if (sb_rdonly(sb)) > + return; > + Should we move some of the comment you deleting over here? > + if (sb->s_iflags & SB_I_NO_DATA_INTEGRITY) > + wakeup_flusher_threads_bdi(sb->s_bdi, WB_REASON_SYNC); > + else > sync_inodes_sb(sb); > } I was wondering whether that handling should be moved to sync_inodes_sb(), so it would catch any (existing+future) callers. Alternatively, we could catch abuse by adding a warning to sync_inodes_sb. -- Cheers, David