Commit 6a7e2bbe authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Dr. David Alan Gilbert
Browse files

docs: add virtiofsd(1) man page 



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: default avatarLiam Merwick <liam.merwick@oracle.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
parent 99ce9a7e

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -1613,6 +1613,7 @@ 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 <kraxel@redhat.com>

Makefile

+8 −1
Original line number Diff line number Diff line
@@ -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)

docs/interop/conf.py

+4 −1
Original line number Diff line number Diff line
@@ -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 <stefanha@redhat.com>',

      'Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>'], 1),

]

docs/interop/index.rst

+1 −0
Original line number Diff line number Diff line
@@ -24,3 +24,4 @@ Contents: 
   vhost-user

   vhost-user-gpu

   virtfs-proxy-helper

   virtiofsd

docs/interop/virtiofsd.rst

0 → 100644
+120 −0
Original line number Diff line number Diff line 
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