[PATCH] doc: Describe missing generic -blockdev options

[Kevin Wolf <kwolf@redhat.com>]

We added more generic options after introducing -blockdev and forgot to
update the documentation (man page and --help output) accordingly. Do
that now.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 qemu-options.hx | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 793d70ff93..9f6aa3dde3 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -849,7 +849,8 @@ ETEXI
 DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev,
     "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n"
     "          [,cache.direct=on|off][,cache.no-flush=on|off]\n"
-    "          [,read-only=on|off][,detect-zeroes=on|off|unmap]\n"
+    "          [,read-only=on|off][,auto-read-only=on|off]\n"
+    "          [,force-share=on|off][,detect-zeroes=on|off|unmap]\n"
     "          [,driver specific parameters...]\n"
     "                configure a block backend\n", QEMU_ARCH_ALL)
 STEXI
@@ -885,6 +886,22 @@ name is not intended to be predictable and changes between QEMU invocations.
 For the top level, an explicit node name must be specified.
 @item read-only
 Open the node read-only. Guest write attempts will fail.
+
+Note that some block drivers support only read-only access, either generally or
+in certain configurations. In this case, the default value
+@option{read-only=off} does not work and the option must be specified
+explicitly.
+@item auto-read-only
+If @option{auto-read-only=on} is set, QEMU is allowed not to open the image
+read-write even if @option{read-only=off} is requested, but fall back to
+read-only instead (and switch between the modes later), e.g. depending on
+whether the image file is writable or whether a writing user is attached to the
+node.
+@item force-share
+Override the image locking system of QEMU and force the node to allowing
+sharing all permissions with other uses.
+
+Enabling @option{force-share=on} requires @option{read-only=on}.
 @item cache.direct
 The host page cache can be avoided with @option{cache.direct=on}. This will
 attempt to do disk IO directly to the guest's memory. QEMU may still perform an
-- 
2.20.1