From nobody Mon Feb 9 11:30:08 2026 Received: from smtp01-ext2.udag.de (smtp01-ext2.udag.de [62.146.106.18]) (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 43C8E47DD71; Thu, 8 Jan 2026 14:23:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.146.106.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767882234; cv=none; b=Jq4dcRRy3kHHXIGzW19aIeHQ5d3oLBOt1Uno9iwz4oaFdjX5kywxJfKcDUqlufBTcA6FX2GD1LNqD4MfHAE77f0T3I5zT8mA6xx9WUenaG0yIR8iTzOY9ZLG4dq9HuVpdbe1x2vYgt9L6kJ9PGGQBzFj6TFemy6LX7cW3qsdlzw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767882234; c=relaxed/simple; bh=c8rfkx/eXAt2tJEKpAeOWNZpo1FPtjGDkOigKSPdCbE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=H9/EIvcB1D3e1XeR7emfkZAL0W1hrr0RZJAW1MD84gaj3kIJN7F2u8zbM/QD0HcytXA9L2eKL5xKjQSCFN69cAUGdzXoNWuatIbE/8WCwIb17ZXh8kJ/klcnJdIHbI1ZqCiecqxJRZQGfe+XXG3ObFY5MdfWhVcfRJ1l3LLBJ9M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=birthelmer.com; spf=pass smtp.mailfrom=birthelmer.com; dkim=pass (2048-bit key) header.d=birthelmer.com header.i=@birthelmer.com header.b=rrfkpwG7; arc=none smtp.client-ip=62.146.106.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=birthelmer.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=birthelmer.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=birthelmer.com header.i=@birthelmer.com header.b="rrfkpwG7" Received: from [127.0.1.1] (049-102-000-128.ip-addr.inexio.net [128.0.102.49]) by smtp01-ext2.udag.de (Postfix) with ESMTPA id 9C6DEE0805; Thu, 8 Jan 2026 15:23:43 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=birthelmer.com; s=uddkim-202310; t=1767882223; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YoBKHUPyRE4dv9HQUx7jnaCpPyk1i4YWKhMO2DACI18=; b=rrfkpwG7RPdwEuw5PGYNm+O9JUfY8xMQ9MDnBqBB8RJqqaLJIYQPgBo/EH3wYK1YyUJMsi qJCpCjc6y+0q24FBB0aiup5JcX9+l9ooKu0CaPQqJHv/6EtUklr2S6lmA8L5/O+JtLrvR8 cQEd2Pt2QvvmZSNKRyMHRnUh2Bn1lQTcP4OLQZHiPiszoOKk5CMnCg4rAak7rqls6vEZ0Z B8Feh0qh7OCPf6qWP+GVQWWOpHKwYgW1dkiViq5RIgUL0kMMT88zAKtrkIYL+RIZi7Bt7q 2QZ/lf48d6ot+A3IWJB5w/nN7AbS2cliNe5us4ct3etMG10420C+M0FroCFhhg== Authentication-Results: smtp01-ext2.udag.de; auth=pass smtp.auth=birthelmercom-0001 smtp.mailfrom=horst@birthelmer.com From: horst@birthelmer.com Date: Thu, 08 Jan 2026 15:23:35 +0100 Subject: [PATCH RFC v3 2/3] fuse: add an implementation of open+getattr Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260108-fuse-compounds-upstream-v3-2-8dc91ebf3740@ddn.com> References: <20260108-fuse-compounds-upstream-v3-0-8dc91ebf3740@ddn.com> In-Reply-To: <20260108-fuse-compounds-upstream-v3-0-8dc91ebf3740@ddn.com> To: Miklos Szeredi , Bernd Schubert , Joanne Koong Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Horst Birthelmer X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1767882221; l=8381; i=hbirthelmer@ddn.com; s=20251006; h=from:subject:message-id; bh=LKb/IffHUUCYsfl1QuQVefttHz9uz5SepmgYOe/ZYbI=; b=NFzNiO9SlOOYMDqQP0sg/443jM9yR/3OLORrOlJ5KaKtGzH7zB5S357JIIXb+RQO6cj0NYkuV /YG+YGUhV5ACBhkFPxD3ukgOPp8R7XM69Kqh0rXvRL7Oj0XbSoDIx90 X-Developer-Key: i=hbirthelmer@ddn.com; a=ed25519; pk=v3BVDFoy16EzgHZ23ObqW+kbpURtjrwxgKu8YNDKjGg= From: Horst Birthelmer The discussion about compound commands in fuse was started over an argument to add a new operation that will open a file and return its attributes in the same operation. Here is a demonstration of that use case with compound commands. Signed-off-by: Horst Birthelmer --- fs/fuse/file.c | 143 ++++++++++++++++++++++++++++++++++++++++++++++++---= ---- fs/fuse/fuse_i.h | 15 +++++- fs/fuse/inode.c | 6 +++ fs/fuse/ioctl.c | 2 +- 4 files changed, 148 insertions(+), 18 deletions(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 01bc894e9c2b..676f6bfde9f8 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -23,6 +23,39 @@ #include #include =20 +/* + * Helper function to initialize fuse_args for OPEN/OPENDIR operations + */ +void fuse_open_args_fill(struct fuse_args *args, u64 nodeid, int opcode, + struct fuse_open_in *inarg, struct fuse_open_out *outarg) +{ + args->opcode =3D opcode; + args->nodeid =3D nodeid; + args->in_numargs =3D 1; + args->in_args[0].size =3D sizeof(*inarg); + args->in_args[0].value =3D inarg; + args->out_numargs =3D 1; + args->out_args[0].size =3D sizeof(*outarg); + args->out_args[0].value =3D outarg; +} + +/* + * Helper function to initialize fuse_args for GETATTR operations + */ +void fuse_getattr_args_fill(struct fuse_args *args, u64 nodeid, + struct fuse_getattr_in *inarg, + struct fuse_attr_out *outarg) +{ + args->opcode =3D FUSE_GETATTR; + args->nodeid =3D nodeid; + args->in_numargs =3D 1; + args->in_args[0].size =3D sizeof(*inarg); + args->in_args[0].value =3D inarg; + args->out_numargs =3D 1; + args->out_args[0].size =3D sizeof(*outarg); + args->out_args[0].value =3D outarg; +} + static int fuse_send_open(struct fuse_mount *fm, u64 nodeid, unsigned int open_flags, int opcode, struct fuse_open_out *outargp) @@ -126,8 +159,66 @@ static void fuse_file_put(struct fuse_file *ff, bool s= ync) } } =20 +static int fuse_compound_open_getattr(struct fuse_mount *fm, u64 nodeid, + int flags, int opcode, + struct fuse_file *ff, + struct fuse_attr_out *outattrp, + struct fuse_open_out *outopenp) +{ + struct fuse_compound_req *compound; + struct fuse_args open_args =3D {}; + struct fuse_args getattr_args =3D {}; + struct fuse_open_in open_in =3D {}; + struct fuse_getattr_in getattr_in =3D {}; + int err; + + compound =3D fuse_compound_alloc(fm, 0); + if (IS_ERR(compound)) + return PTR_ERR(compound); + + open_in.flags =3D flags & ~(O_CREAT | O_EXCL | O_NOCTTY); + if (!fm->fc->atomic_o_trunc) + open_in.flags &=3D ~O_TRUNC; + + if (fm->fc->handle_killpriv_v2 && + (open_in.flags & O_TRUNC) && !capable(CAP_FSETID)) + open_in.open_flags |=3D FUSE_OPEN_KILL_SUIDGID; + + fuse_open_args_fill(&open_args, nodeid, opcode, &open_in, outopenp); + + err =3D fuse_compound_add(compound, &open_args); + if (err) + goto out; + + fuse_getattr_args_fill(&getattr_args, nodeid, &getattr_in, outattrp); + + err =3D fuse_compound_add(compound, &getattr_args); + if (err) + goto out; + + err =3D fuse_compound_send(compound); + if (err) + goto out; + + err =3D fuse_compound_get_error(compound, 0); + if (err) + goto out; + + err =3D fuse_compound_get_error(compound, 1); + if (err) + goto out; + + ff->fh =3D outopenp->fh; + ff->open_flags =3D outopenp->open_flags; + +out: + fuse_compound_free(compound); + return err; +} + struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid, - unsigned int open_flags, bool isdir) + struct inode *inode, + unsigned int open_flags, bool isdir) { struct fuse_conn *fc =3D fm->fc; struct fuse_file *ff; @@ -153,23 +244,44 @@ struct fuse_file *fuse_file_open(struct fuse_mount *f= m, u64 nodeid, if (open) { /* Store outarg for fuse_finish_open() */ struct fuse_open_out *outargp =3D &ff->args->open_outarg; - int err; + int err =3D -ENOSYS; + + if (inode && fc->compound_open_getattr) { + struct fuse_attr_out attr_outarg; + + err =3D fuse_compound_open_getattr(fm, nodeid, open_flags, + opcode, ff, + &attr_outarg, outargp); + if (!err) + fuse_change_attributes(inode, &attr_outarg.attr, + NULL, + ATTR_TIMEOUT(&attr_outarg), + fuse_get_attr_version(fc)); + } + if (err =3D=3D -ENOSYS) { + err =3D fuse_send_open(fm, nodeid, open_flags, opcode, + outargp); + if (!err) { + ff->fh =3D outargp->fh; + ff->open_flags =3D outargp->open_flags; + } + } =20 - err =3D fuse_send_open(fm, nodeid, open_flags, opcode, outargp); - if (!err) { - ff->fh =3D outargp->fh; - ff->open_flags =3D outargp->open_flags; - } else if (err !=3D -ENOSYS) { - fuse_file_free(ff); - return ERR_PTR(err); - } else { - if (isdir) { + if (err) { + if (err !=3D -ENOSYS) { + /* err is not ENOSYS */ + fuse_file_free(ff); + return ERR_PTR(err); + } else { /* No release needed */ kfree(ff->args); ff->args =3D NULL; - fc->no_opendir =3D 1; - } else { - fc->no_open =3D 1; + + /* we don't have open */ + if (isdir) + fc->no_opendir =3D 1; + else + fc->no_open =3D 1; } } } @@ -185,11 +297,10 @@ struct fuse_file *fuse_file_open(struct fuse_mount *f= m, u64 nodeid, int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file, bool isdir) { - struct fuse_file *ff =3D fuse_file_open(fm, nodeid, file->f_flags, isdir); + struct fuse_file *ff =3D fuse_file_open(fm, nodeid, file_inode(file), fil= e->f_flags, isdir); =20 if (!IS_ERR(ff)) file->private_data =3D ff; - return PTR_ERR_OR_ZERO(ff); } EXPORT_SYMBOL_GPL(fuse_do_open); diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 6dddbe2b027b..e7828405e262 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -924,6 +924,9 @@ struct fuse_conn { /* Use io_uring for communication */ unsigned int io_uring; =20 + /* Does the filesystem support compound operations? */ + unsigned int compound_open_getattr:1; + /** Maximum stack depth for passthrough backing files */ int max_stack_depth; =20 @@ -1179,6 +1182,14 @@ struct fuse_io_args { void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_= t pos, size_t count, int opcode); =20 +/* + * Helper functions to initialize fuse_args for common operations + */ +void fuse_open_args_fill(struct fuse_args *args, u64 nodeid, int opcode, + struct fuse_open_in *inarg, struct fuse_open_out *outarg); +void fuse_getattr_args_fill(struct fuse_args *args, u64 nodeid, + struct fuse_getattr_in *inarg, + struct fuse_attr_out *outarg); =20 struct fuse_file *fuse_file_alloc(struct fuse_mount *fm, bool release); void fuse_file_free(struct fuse_file *ff); @@ -1555,7 +1566,9 @@ void fuse_file_io_release(struct fuse_file *ff, struc= t inode *inode); =20 /* file.c */ struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid, - unsigned int open_flags, bool isdir); + struct inode *inode, + unsigned int open_flags, + bool isdir); void fuse_file_release(struct inode *inode, struct fuse_file *ff, unsigned int open_flags, fl_owner_t id, bool isdir); =20 diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 819e50d66622..a5fd721be96d 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -991,6 +991,12 @@ void fuse_conn_init(struct fuse_conn *fc, struct fuse_= mount *fm, fc->blocked =3D 0; fc->initialized =3D 0; fc->connected =3D 1; + + /* pretend fuse server supports compound operations + * until it tells us otherwise. + */ + fc->compound_open_getattr =3D 1; + atomic64_set(&fc->attr_version, 1); atomic64_set(&fc->evict_ctr, 1); get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); diff --git a/fs/fuse/ioctl.c b/fs/fuse/ioctl.c index fdc175e93f74..07a02e47b2c3 100644 --- a/fs/fuse/ioctl.c +++ b/fs/fuse/ioctl.c @@ -494,7 +494,7 @@ static struct fuse_file *fuse_priv_ioctl_prepare(struct= inode *inode) if (!S_ISREG(inode->i_mode) && !isdir) return ERR_PTR(-ENOTTY); =20 - return fuse_file_open(fm, get_node_id(inode), O_RDONLY, isdir); + return fuse_file_open(fm, get_node_id(inode), NULL, O_RDONLY, isdir); } =20 static void fuse_priv_ioctl_cleanup(struct inode *inode, struct fuse_file = *ff) --=20 2.51.0