This documentation is modified from cifs/cifsroot.rst.
Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>
---
Documentation/filesystems/v9fs/index.rst | 1 +
Documentation/filesystems/v9fs/v9fsroot.rst | 52 +++++++++++++++++++++
MAINTAINERS | 1 +
3 files changed, 54 insertions(+)
create mode 100644 Documentation/filesystems/v9fs/v9fsroot.rst
diff --git a/Documentation/filesystems/v9fs/index.rst b/Documentation/filesystems/v9fs/index.rst
index a1e45b89e2a2..65e1ceb04c9c 100644
--- a/Documentation/filesystems/v9fs/index.rst
+++ b/Documentation/filesystems/v9fs/index.rst
@@ -9,3 +9,4 @@ v9fs
:numbered:
9p
+ v9fsroot
diff --git a/Documentation/filesystems/v9fs/v9fsroot.rst b/Documentation/filesystems/v9fs/v9fsroot.rst
new file mode 100644
index 000000000000..ce6b3c85e301
--- /dev/null
+++ b/Documentation/filesystems/v9fs/v9fsroot.rst
@@ -0,0 +1,52 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==========================================
+Mounting root file system via v9fs (9p.ko)
+==========================================
+
+:Author: Changbin Du <changbin.du@xxxxxxxxx>
+
+The CONFIG_9P_FS_ROOT option enables experimental root file system
+support for v9fs.
+
+It introduces a new kernel command-line option called 'v9fsroot='
+which will tell the kernel to mount the root file system by
+utilizing the 9p protocol.
+
+
+Kernel command line
+===================
+
+::
+
+ root=/dev/v9fs
+
+This is just a virtual device that basically tells the kernel to mount
+the root file system via 9p protocol.
+
+::
+
+ v9fsroot=<path>[,options]
+
+Enables the kernel to mount the root file system via 9p specified in this
+option.
+
+path
+ Could be a remote file server, Plan 9 From User Space applications
+ or mount tag of virtio transport.
+
+options
+ Optional mount options.
+
+Examples
+========
+Test it under QEMU on a kernel built with CONFIG_9P_FS_ROOT and
+CONFIG_IP_PNP options enabled::
+
+ # qemu-system-x86_64 -enable-kvm -cpu host -m 1024 \
+ -virtfs local,path=$rootfs_dir,mount_tag=r,security_model=passthrough,id=r \
+ -kernel /path/to/linux/arch/x86/boot/bzImage -nographic \
+ -append "root=/dev/v9fs v9fsroot=r,trans=virtio rw console=ttyS0 3"
+
+The above example mounts v9fs with tag 'r' as rootfs in qemu guest via
+virtio transport.
diff --git a/MAINTAINERS b/MAINTAINERS
index 2d22e2af4d10..8c585d387f61 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -243,6 +243,7 @@ F: net/9p/
R: Changbin Du <changbin.du@xxxxxxxxx>
S: Supported
F: fs/9p/v9fsroot.c
+F: Documentation/filesystems/v9fs/v9fsroot.rst
A8293 MEDIA DRIVER
M: Antti Palosaari <crope@xxxxxx>
--
2.30.2
