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 EB8E836B054; Mon, 23 Feb 2026 23:32:39 +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=1771889560; cv=none; b=FzdbejtblbU4mtfQ4ZfriaTof7GEPKIw7VfiY+uErJIUwR0rKloICwVwECtIHrW0s09KhlptKfHf7+xKIgrANC/m+Pn+OQZvfQZo4AGWGhEmetlFuxouok8Y7bFIgyF8X77ncOgIH9BEM5tv3kIvTjD8KDqwBIbYku6fKHl4x9A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771889560; c=relaxed/simple; bh=K32OCWitPVfFFZQUmaLqurP2mPvgEvRO8HwQB5M4wyQ=; h=Date:Subject:From:To:Cc:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=M3vWIT8sL7ilNk9UFJ8jHLy2VlF38Ut0fJksal9gWUnercW8KL92QBcMhe79vMvwB7MtL4EDw99dW/3Fvx/KHwrHp3fRm18uTU2xmKYm0jbSW4KqNAg8AV/S8LSajA2WZfYZIHdmQopXfZT/LUsqbAbdaSlzv/aKcrCH6/9nXgE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OBsrdQvu; 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="OBsrdQvu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97680C116C6; Mon, 23 Feb 2026 23:32:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771889559; bh=K32OCWitPVfFFZQUmaLqurP2mPvgEvRO8HwQB5M4wyQ=; h=Date:Subject:From:To:Cc:In-Reply-To:References:From; b=OBsrdQvuaVd14YM81/21WcI42Xb9eekC4SJV0zQnAQsMzkxMLwtfQN10N8CRrABvE 62b8P20ptbQtaWlnS0KIMF5HBMVez/l3peX+7RUJWfsTjbnWi4aanyOfur+HteIiTX 7su/SbrXsrIorYxTpFPEx8Z9WBK2IBvdzZ53z+n4MLe9FwBwBWCD70fXcQohdbQshV HMWn+km3fmdxbeu7APEn1Nl260Z/29o/+bKm/vMSYM0CWEJZuoqkfJ1Y8rcbA5rt/O YU17HipsfM0yP3RI3JevJAPtCFYtnsqBE6W01h2zuN89e8xOjPdrVrqnhnxbdVOPFN Mum4zDdHfqdQg== Date: Mon, 23 Feb 2026 15:32:39 -0800 Subject: [PATCH 2/2] libfuse: set sync, immutable, and append when loading files 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: <177188740809.3941738.14644457167260941533.stgit@frogsfrogsfrogs> In-Reply-To: <177188740769.3941738.15253689862800289077.stgit@frogsfrogsfrogs> References: <177188740769.3941738.15253689862800289077.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 these three fuse_attr::flags bits so that servers can mark a file as immutable or append-only and have the kernel advertise and enforce that. Signed-off-by: "Darrick J. Wong" --- include/fuse_common.h | 6 ++++++ include/fuse_kernel.h | 8 ++++++++ lib/fuse_lowlevel.c | 6 ++++++ 3 files changed, 20 insertions(+) diff --git a/include/fuse_common.h b/include/fuse_common.h index a8aec81ec123a2..d1bd783cd667c7 100644 --- a/include/fuse_common.h +++ b/include/fuse_common.h @@ -1243,6 +1243,12 @@ static inline bool fuse_iomap_need_write_allocate(unsigned int opflags, #define FUSE_IFLAG_IOMAP (1U << 2) /* enable untorn writes */ #define FUSE_IFLAG_ATOMIC (1U << 3) +/* file writes are synchronous */ +#define FUSE_IFLAG_SYNC (1U << 4) +/* file is immutable */ +#define FUSE_IFLAG_IMMUTABLE (1U << 5) +/* file is append only */ +#define FUSE_IFLAG_APPEND (1U << 6) /* 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 ff21973e1c88f7..bee825a6d17ad5 100644 --- a/include/fuse_kernel.h +++ b/include/fuse_kernel.h @@ -249,6 +249,8 @@ * - 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 + * - add FUSE_ATTR_{SYNC,IMMUTABLE,APPEND} for VFS enforcement of file + * attributes */ #ifndef _LINUX_FUSE_H @@ -593,12 +595,18 @@ struct fuse_file_lock { * 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 + * FUSE_ATTR_SYNC: File writes are always synchronous + * FUSE_ATTR_IMMUTABLE: File is immutable + * FUSE_ATTR_APPEND: File is append-only */ #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) +#define FUSE_ATTR_SYNC (1 << 5) +#define FUSE_ATTR_IMMUTABLE (1 << 6) +#define FUSE_ATTR_APPEND (1 << 7) /** * Open flags diff --git a/lib/fuse_lowlevel.c b/lib/fuse_lowlevel.c index 18503a1fa64d88..7b501e2f3ef047 100644 --- a/lib/fuse_lowlevel.c +++ b/lib/fuse_lowlevel.c @@ -170,6 +170,12 @@ static void convert_stat(const struct stat *stbuf, struct fuse_attr *attr, attr->flags |= FUSE_ATTR_IOMAP; if (iflags & FUSE_IFLAG_ATOMIC) attr->flags |= FUSE_ATTR_ATOMIC; + if (iflags & FUSE_IFLAG_SYNC) + attr->flags |= FUSE_ATTR_SYNC; + if (iflags & FUSE_IFLAG_IMMUTABLE) + attr->flags |= FUSE_ATTR_IMMUTABLE; + if (iflags & FUSE_IFLAG_APPEND) + attr->flags |= FUSE_ATTR_APPEND; } static void convert_attr(const struct fuse_setattr_in *attr, struct stat *stbuf)