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Re: [PATCH v3] docs: add virtiofsd(1) man page
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [PATCH v3] docs: add virtiofsd(1) man page |
Date: |
Fri, 7 Feb 2020 16:43:40 +0000 |
User-agent: |
Mutt/1.13.3 (2020-01-12) |
* Stefan Hajnoczi (address@hidden) wrote:
> Document the virtiofsd(1) program and its command-line options. This
> man page is a rST conversion of the original texi documentation that I
> wrote.
>
> Reviewed-by: Liam Merwick <address@hidden>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
I'll add this to my stack for a virtiofs pull.
Dave
> ---
> v3:
> * Dropped old -o vhost_user_socket=PATH option [dgilbert]
> v2:
> * Fix mount -t virtio_fs -> virtiofs outdated doc [Liam]
> * Use memory-backend-memfd instead of memory-backend-file
> ---
> MAINTAINERS | 1 +
> Makefile | 9 ++-
> docs/interop/conf.py | 5 +-
> docs/interop/index.rst | 1 +
> docs/interop/virtiofsd.rst | 120 +++++++++++++++++++++++++++++++++++++
> 5 files changed, 134 insertions(+), 2 deletions(-)
> create mode 100644 docs/interop/virtiofsd.rst
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e72b5e5f69..4a118fe504 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1612,6 +1612,7 @@ S: Supported
> F: tools/virtiofsd/*
> F: hw/virtio/vhost-user-fs*
> F: include/hw/virtio/vhost-user-fs.h
> +F: docs/interop/virtiofsd.rst
>
> virtio-input
> M: Gerd Hoffmann <address@hidden>
> diff --git a/Makefile b/Makefile
> index 461d40bea6..f0e1a2fc1d 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -348,6 +348,9 @@ DOCS=qemu-doc.html qemu-doc.txt qemu.1
> DOCS+=$(MANUAL_BUILDDIR)/interop/qemu-img.1
> DOCS+=$(MANUAL_BUILDDIR)/interop/qemu-nbd.8
> DOCS+=$(MANUAL_BUILDDIR)/interop/qemu-ga.8
> +ifeq ($(CONFIG_LINUX)$(CONFIG_SECCOMP)$(CONFIG_LIBCAP_NG),yyy)
> +DOCS+=$(MANUAL_BUILDDIR)/interop/virtiofsd.1
> +endif
> DOCS+=$(MANUAL_BUILDDIR)/system/qemu-block-drivers.7
> DOCS+=docs/interop/qemu-qmp-ref.html docs/interop/qemu-qmp-ref.txt
> docs/interop/qemu-qmp-ref.7
> DOCS+=docs/interop/qemu-ga-ref.html docs/interop/qemu-ga-ref.txt
> docs/interop/qemu-ga-ref.7
> @@ -861,6 +864,9 @@ ifdef CONFIG_VIRTFS
> $(INSTALL_DIR) "$(DESTDIR)$(mandir)/man1"
> $(INSTALL_DATA) $(MANUAL_BUILDDIR)/interop/virtfs-proxy-helper.1
> "$(DESTDIR)$(mandir)/man1"
> endif
> +ifeq ($(CONFIG_LINUX)$(CONFIG_SECCOMP)$(CONFIG_LIBCAP_NG),yyy)
> + $(INSTALL_DATA) docs/interop/virtiofsd.1 "$(DESTDIR)$(mandir)/man1"
> +endif
>
> install-datadir:
> $(INSTALL_DIR) "$(DESTDIR)$(qemu_datadir)"
> @@ -1051,7 +1057,8 @@ $(MANUAL_BUILDDIR)/system/index.html: $(call
> manual-deps,system)
> $(call build-manual,system,html)
>
> $(call define-manpage-rule,interop,\
> - qemu-ga.8 qemu-img.1 qemu-nbd.8 qemu-trace-stap.1
> virtfs-proxy-helper.1,\
> + qemu-ga.8 qemu-img.1 qemu-nbd.8 qemu-trace-stap.1\
> + virtiofsd.1 virtfs-proxy-helper.1,\
> $(SRC_PATH/qemu-img-cmds.hx))
>
> $(call define-manpage-rule,system,qemu-block-drivers.7)
> diff --git a/docs/interop/conf.py b/docs/interop/conf.py
> index b0f322207c..b3cda17042 100644
> --- a/docs/interop/conf.py
> +++ b/docs/interop/conf.py
> @@ -27,5 +27,8 @@ man_pages = [
> [], 1),
> ('virtfs-proxy-helper', 'virtfs-proxy-helper',
> u'QEMU 9p virtfs proxy filesystem helper',
> - ['M. Mohan Kumar'], 1)
> + ['M. Mohan Kumar'], 1),
> + ('virtiofsd', 'virtiofsd', u'QEMU virtio-fs shared file system daemon',
> + ['Stefan Hajnoczi <address@hidden>',
> + 'Masayoshi Mizuma <address@hidden>'], 1),
> ]
> diff --git a/docs/interop/index.rst b/docs/interop/index.rst
> index 3b763b1eeb..e8455b4270 100644
> --- a/docs/interop/index.rst
> +++ b/docs/interop/index.rst
> @@ -24,3 +24,4 @@ Contents:
> vhost-user
> vhost-user-gpu
> virtfs-proxy-helper
> + virtiofsd
> diff --git a/docs/interop/virtiofsd.rst b/docs/interop/virtiofsd.rst
> new file mode 100644
> index 0000000000..378594c422
> --- /dev/null
> +++ b/docs/interop/virtiofsd.rst
> @@ -0,0 +1,120 @@
> +QEMU virtio-fs shared file system daemon
> +========================================
> +
> +Synopsis
> +--------
> +
> +**virtiofsd** [*OPTIONS*]
> +
> +Description
> +-----------
> +
> +Share a host directory tree with a guest through a virtio-fs device. This
> +program is a vhost-user backend that implements the virtio-fs device. Each
> +virtio-fs device instance requires its own virtiofsd process.
> +
> +This program is designed to work with QEMU's ``--device vhost-user-fs-pci``
> +but should work with any virtual machine monitor (VMM) that supports
> +vhost-user. See the Examples section below.
> +
> +This program must be run as the root user. Upon startup the program will
> +switch into a new file system namespace with the shared directory tree as its
> +root. This prevents "file system escapes" due to symlinks and other file
> +system objects that might lead to files outside the shared directory. The
> +program also sandboxes itself using seccomp(2) to prevent ptrace(2) and other
> +vectors that could allow an attacker to compromise the system after gaining
> +control of the virtiofsd process.
> +
> +Options
> +-------
> +
> +.. program:: virtiofsd
> +
> +.. option:: -h, --help
> +
> + Print help.
> +
> +.. option:: -V, --version
> +
> + Print version.
> +
> +.. option:: -d
> +
> + Enable debug output.
> +
> +.. option:: --syslog
> +
> + Print log messages to syslog instead of stderr.
> +
> +.. option:: -o OPTION
> +
> + * debug -
> + Enable debug output.
> +
> + * flock|no_flock -
> + Enable/disable flock. The default is ``no_flock``.
> +
> + * log_level=LEVEL -
> + Print only log messages matching LEVEL or more severe. LEVEL is one of
> + ``err``, ``warn``, ``info``, or ``debug``. The default is ``info``.
> +
> + * norace -
> + Disable racy fallback. The default is false.
> +
> + * posix_lock|no_posix_lock -
> + Enable/disable remote POSIX locks. The default is ``posix_lock``.
> +
> + * readdirplus|no_readdirplus -
> + Enable/disable readdirplus. The default is ``readdirplus``.
> +
> + * source=PATH -
> + Share host directory tree located at PATH. This option is required.
> +
> + * timeout=TIMEOUT -
> + I/O timeout in seconds. The default depends on cache= option.
> +
> + * writeback|no_writeback -
> + Enable/disable writeback cache. The cache alows the FUSE client to buffer
> + and merge write requests. The default is ``no_writeback``.
> +
> + * xattr|no_xattr -
> + Enable/disable extended attributes (xattr) on files and directories. The
> + default is ``no_xattr``.
> +
> +.. option:: --socket-path=PATH
> +
> + Listen on vhost-user UNIX domain socket at PATH.
> +
> +.. option:: --fd=FDNUM
> +
> + Accept connections from vhost-user UNIX domain socket file descriptor
> FDNUM.
> + The file descriptor must already be listening for connections.
> +
> +.. option:: --thread-pool-size=NUM
> +
> + Restrict the number of worker threads per request queue to NUM. The
> default
> + is 64.
> +
> +.. option:: --cache=none|auto|always
> +
> + Select the desired trade-off between coherency and performance. ``none``
> + forbids the FUSE client from caching to achieve best coherency at the cost
> of
> + performance. ``auto`` acts similar to NFS with a 1 second metadata cache
> + timeout. ``always`` sets a long cache lifetime at the expense of
> coherency.
> +
> +Examples
> +--------
> +
> +Export ``/var/lib/fs/vm001/`` on vhost-user UNIX domain socket
> +``/var/run/vm001-vhost-fs.sock``:
> +
> +::
> +
> + host# virtiofsd --socket-path=/var/run/vm001-vhost-fs.sock -o
> source=/var/lib/fs/vm001
> + host# qemu-system-x86_64 \
> + -chardev socket,id=char0,path=/var/run/vm001-vhost-fs.sock \
> + -device vhost-user-fs-pci,chardev=char0,tag=myfs \
> + -object memory-backend-memfd,id=mem,size=4G,share=on \
> + -numa node,memdev=mem \
> + ...
> + guest# mount -t virtiofs myfs /mnt
> --
> 2.24.1
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK