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 125A237BE9E; Mon, 23 Feb 2026 23:30:34 +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=1771889435; cv=none; b=ngrEFfdsorApvYQghjT6yYSXBqu42D9Krn6+xsPWI+t7g40uja0jil26p4vKMYZc4z17SUhLMOKYnnvpC92slt4J8pt5/fqpjwqyb2yFX7VDYvWSeH92gclimneJ38C6hZIu1V0QvULK7rWSmL//oFzCFKp9loA8HZkDFT+yPJE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771889435; c=relaxed/simple; bh=8Ob4rSOeJC/BZYNGuQFHKOtdOn2PmNT7CLSPZHmMpsQ=; h=Date:Subject:From:To:Cc:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=nFfm6eilCTbcdPn+57OiLVxBtniJ95Kvx/qymDhiad686vlu97g01jyX3gJC1c8M4b9xqqRPAeYtkP1vOf+eSHVg64JuWkaWUI8yX4Xwf/e4vcFCc33AxWt3eArGOFFT9ctkbPBvvmkV8vjZeGX9XpW9+e8fRJtitbnpFOLalLc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ojFnLY6p; 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="ojFnLY6p" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A94C9C116C6; Mon, 23 Feb 2026 23:30:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771889434; bh=8Ob4rSOeJC/BZYNGuQFHKOtdOn2PmNT7CLSPZHmMpsQ=; h=Date:Subject:From:To:Cc:In-Reply-To:References:From; b=ojFnLY6pTJZsWfX6sWGVOSWo5YKBToC4Datm22Dko0p1Of3T/YfEtLRUkHH2EWBes +Jaxl/ol5HlFspbFqy8eC5ki4Hfey1tKt3t6hb1D0UtqvRK8lKuCu4B+DGrDGRLnji eHTLf4MGfi1Ef9rxvYnD1Q6UArFv8OnN/yaawhb4NGfC1pxTQfGXPJg3eGms09voyD TWW1jRPVI3i/VW4IpXftmCwpBvkKp34+s72UlLC4j9UI2Mn8hoZp6YX+bAV6hcBNC/ s0wBCZvWq1sTG4S6udaXz60uIr8kdkC7/2NQtlt3Gld/5ADpXSIJhboQ6E4OsjklaC 8H8yVCRIrrv0A== Date: Mon, 23 Feb 2026 15:30:34 -0800 Subject: [PATCH 20/25] libfuse: add atomic write support From: "Darrick J. Wong" To: djwong@kernel.org, bschubert@ddn.com Cc: bernd@bsbernd.com, miklos@szeredi.hu, neal@gompa.dev, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org, joannelkoong@gmail.com Message-ID: <177188740292.3940670.15942150548008378091.stgit@frogsfrogsfrogs> In-Reply-To: <177188739839.3940670.15233996351019069073.stgit@frogsfrogsfrogs> References: <177188739839.3940670.15233996351019069073.stgit@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit From: Darrick J. Wong Add the single flag that we need to turn on atomic write support in fuse. Signed-off-by: "Darrick J. Wong" --- include/fuse_common.h | 4 ++++ include/fuse_kernel.h | 3 +++ lib/fuse_lowlevel.c | 2 ++ 3 files changed, 9 insertions(+) diff --git a/include/fuse_common.h b/include/fuse_common.h index 2f6672fc14d90d..a42d70f79d57e1 100644 --- a/include/fuse_common.h +++ b/include/fuse_common.h @@ -540,6 +540,8 @@ struct fuse_loop_config_v1 { * FUSE_IOMAP_SUPPORT_FILEIO: basic file I/O functionality through iomap */ #define FUSE_IOMAP_SUPPORT_FILEIO (1ULL << 0) +/* untorn writes through iomap */ +#define FUSE_IOMAP_SUPPORT_ATOMIC (1ULL << 1) /** * Connection information, passed to the ->init() method @@ -1234,6 +1236,8 @@ static inline bool fuse_iomap_need_write_allocate(unsigned int opflags, #define FUSE_IFLAG_EXCLUSIVE (1U << 1) /* use iomap for this inode */ #define FUSE_IFLAG_IOMAP (1U << 2) +/* enable untorn writes */ +#define FUSE_IFLAG_ATOMIC (1U << 3) /* Which fields are set in fuse_iomap_config_out? */ #define FUSE_IOMAP_CONFIG_SID (1 << 0ULL) diff --git a/include/fuse_kernel.h b/include/fuse_kernel.h index 1e7c9d8082cf23..71a6a92b4b4a65 100644 --- a/include/fuse_kernel.h +++ b/include/fuse_kernel.h @@ -248,6 +248,7 @@ * - add FUSE_ATTR_IOMAP to enable iomap for specific inodes * - add FUSE_IOMAP_CONFIG so the fuse server can configure more fs geometry * - add FUSE_NOTIFY_IOMAP_DEV_INVAL to invalidate iomap bdev ranges + * - add FUSE_ATTR_ATOMIC for single-fsblock atomic write support */ #ifndef _LINUX_FUSE_H @@ -591,11 +592,13 @@ struct fuse_file_lock { * FUSE_ATTR_EXCLUSIVE: This file can only be modified by this mount, so the * kernel can use cached attributes more aggressively (e.g. ACL inheritance) * FUSE_ATTR_IOMAP: Use iomap for this inode + * FUSE_ATTR_ATOMIC: Enable untorn writes */ #define FUSE_ATTR_SUBMOUNT (1 << 0) #define FUSE_ATTR_DAX (1 << 1) #define FUSE_ATTR_EXCLUSIVE (1 << 2) #define FUSE_ATTR_IOMAP (1 << 3) +#define FUSE_ATTR_ATOMIC (1 << 4) /** * Open flags diff --git a/lib/fuse_lowlevel.c b/lib/fuse_lowlevel.c index 89e26f207addbf..91aaf6a1183d30 100644 --- a/lib/fuse_lowlevel.c +++ b/lib/fuse_lowlevel.c @@ -168,6 +168,8 @@ static void convert_stat(const struct stat *stbuf, struct fuse_attr *attr, attr->flags |= FUSE_ATTR_EXCLUSIVE; if (iflags & FUSE_IFLAG_IOMAP) attr->flags |= FUSE_ATTR_IOMAP; + if (iflags & FUSE_IFLAG_ATOMIC) + attr->flags |= FUSE_ATTR_ATOMIC; } static void convert_attr(const struct fuse_setattr_in *attr, struct stat *stbuf)