docs/interop/nbd.txt: Convert to rST

Convert nbd.txt to rST format.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20240801170131.3977807-3-peter.maydell@linaro.org

3 files changed, 90 insertions, 72 deletions

diff --git a/docs/interop/index.rst b/docs/interop/index.rst
index ed65395bfb..b9ceaabc64 100644
--- a/docs/interop/index.rst
+++ b/docs/interop/index.rst
@@ -14,6 +14,7 @@ are useful for making QEMU interoperate with other software.
    dbus-vmstate
    dbus-display
    live-block-operations
+   nbd
    pr-helper
    qmp-spec
    qemu-ga
diff --git a/docs/interop/nbd.rst b/docs/interop/nbd.rst
new file mode 100644
index 0000000000..de079d31fd
--- /dev/null
+++ b/docs/interop/nbd.rst
@@ -0,0 +1,89 @@
+QEMU NBD protocol support
+=========================
+
+QEMU supports the NBD protocol, and has an internal NBD client (see
+``block/nbd.c``), an internal NBD server (see ``blockdev-nbd.c``), and an
+external NBD server tool (see ``qemu-nbd.c``). The common code is placed
+in ``nbd/*``.
+
+The NBD protocol is specified here:
+https://github.com/NetworkBlockDevice/nbd/blob/master/doc/proto.md
+
+The following paragraphs describe some specific properties of NBD
+protocol realization in QEMU.
+
+Metadata namespaces
+-------------------
+
+QEMU supports the ``base:allocation`` metadata context as defined in the
+NBD protocol specification, and also defines an additional metadata
+namespace ``qemu``.
+
+``qemu`` namespace
+------------------
+
+The ``qemu`` namespace currently contains two available metadata context
+types.  The first is related to exposing the contents of a dirty
+bitmap alongside the associated disk contents.  That metadata context
+is named with the following form::
+
+    qemu:dirty-bitmap:<dirty-bitmap-export-name>
+
+Each dirty-bitmap metadata context defines only one flag for extents
+in reply for ``NBD_CMD_BLOCK_STATUS``:
+
+bit 0:
+  ``NBD_STATE_DIRTY``, set when the extent is "dirty"
+
+The second is related to exposing the source of various extents within
+the image, with a single metadata context named::
+
+    qemu:allocation-depth
+
+In the allocation depth context, the entire 32-bit value represents a
+depth of which layer in a thin-provisioned backing chain provided the
+data (0 for unallocated, 1 for the active layer, 2 for the first
+backing layer, and so forth).
+
+For ``NBD_OPT_LIST_META_CONTEXT`` the following queries are supported
+in addition to the specific ``qemu:allocation-depth`` and
+``qemu:dirty-bitmap:<dirty-bitmap-export-name>``:
+
+``qemu:``
+  returns list of all available metadata contexts in the namespace
+``qemu:dirty-bitmap:``
+  returns list of all available dirty-bitmap metadata contexts
+
+Features by version
+-------------------
+
+The following list documents which qemu version first implemented
+various features (both as a server exposing the feature, and as a
+client taking advantage of the feature when present), to make it
+easier to plan for cross-version interoperability.  Note that in
+several cases, the initial release containing a feature may require
+additional patches from the corresponding stable branch to fix bugs in
+the operation of that feature.
+
+2.6
+  ``NBD_OPT_STARTTLS`` with TLS X.509 Certificates
+2.8
+  ``NBD_CMD_WRITE_ZEROES``
+2.10
+  ``NBD_OPT_GO``, ``NBD_INFO_BLOCK``
+2.11
+  ``NBD_OPT_STRUCTURED_REPLY``
+2.12
+  ``NBD_CMD_BLOCK_STATUS`` for ``base:allocation``
+3.0
+  ``NBD_OPT_STARTTLS`` with TLS Pre-Shared Keys (PSK),
+  ``NBD_CMD_BLOCK_STATUS`` for ``qemu:dirty-bitmap:``, ``NBD_CMD_CACHE``
+4.2
+  ``NBD_FLAG_CAN_MULTI_CONN`` for shareable read-only exports,
+  ``NBD_CMD_FLAG_FAST_ZERO``
+5.2
+  ``NBD_CMD_BLOCK_STATUS`` for ``qemu:allocation-depth``
+7.1
+  ``NBD_FLAG_CAN_MULTI_CONN`` for shareable writable exports
+8.2
+  ``NBD_OPT_EXTENDED_HEADERS``, ``NBD_FLAG_BLOCK_STATUS_PAYLOAD``
diff --git a/docs/interop/nbd.txt b/docs/interop/nbd.txt
deleted file mode 100644
index 18efb251de..0000000000
--- a/docs/interop/nbd.txt
+++ /dev/null
@@ -1,72 +0,0 @@
-QEMU supports the NBD protocol, and has an internal NBD client (see
-block/nbd.c), an internal NBD server (see blockdev-nbd.c), and an
-external NBD server tool (see qemu-nbd.c). The common code is placed
-in nbd/*.
-
-The NBD protocol is specified here:
-https://github.com/NetworkBlockDevice/nbd/blob/master/doc/proto.md
-
-The following paragraphs describe some specific properties of NBD
-protocol realization in QEMU.
-
-= Metadata namespaces =
-
-QEMU supports the "base:allocation" metadata context as defined in the
-NBD protocol specification, and also defines an additional metadata
-namespace "qemu".
-
-== "qemu" namespace ==
-
-The "qemu" namespace currently contains two available metadata context
-types.  The first is related to exposing the contents of a dirty
-bitmap alongside the associated disk contents.  That metadata context
-is named with the following form:
-
-    qemu:dirty-bitmap:<dirty-bitmap-export-name>
-
-Each dirty-bitmap metadata context defines only one flag for extents
-in reply for NBD_CMD_BLOCK_STATUS:
-
-    bit 0: NBD_STATE_DIRTY, set when the extent is "dirty"
-
-The second is related to exposing the source of various extents within
-the image, with a single metadata context named:
-
-    qemu:allocation-depth
-
-In the allocation depth context, the entire 32-bit value represents a
-depth of which layer in a thin-provisioned backing chain provided the
-data (0 for unallocated, 1 for the active layer, 2 for the first
-backing layer, and so forth).
-
-For NBD_OPT_LIST_META_CONTEXT the following queries are supported
-in addition to the specific "qemu:allocation-depth" and
-"qemu:dirty-bitmap:<dirty-bitmap-export-name>":
-
-* "qemu:" - returns list of all available metadata contexts in the
-            namespace.
-* "qemu:dirty-bitmap:" - returns list of all available dirty-bitmap
-                         metadata contexts.
-
-= Features by version =
-
-The following list documents which qemu version first implemented
-various features (both as a server exposing the feature, and as a
-client taking advantage of the feature when present), to make it
-easier to plan for cross-version interoperability.  Note that in
-several cases, the initial release containing a feature may require
-additional patches from the corresponding stable branch to fix bugs in
-the operation of that feature.
-
-* 2.6: NBD_OPT_STARTTLS with TLS X.509 Certificates
-* 2.8: NBD_CMD_WRITE_ZEROES
-* 2.10: NBD_OPT_GO, NBD_INFO_BLOCK
-* 2.11: NBD_OPT_STRUCTURED_REPLY
-* 2.12: NBD_CMD_BLOCK_STATUS for "base:allocation"
-* 3.0: NBD_OPT_STARTTLS with TLS Pre-Shared Keys (PSK),
-NBD_CMD_BLOCK_STATUS for "qemu:dirty-bitmap:", NBD_CMD_CACHE
-* 4.2: NBD_FLAG_CAN_MULTI_CONN for shareable read-only exports,
-NBD_CMD_FLAG_FAST_ZERO
-* 5.2: NBD_CMD_BLOCK_STATUS for "qemu:allocation-depth"
-* 7.1: NBD_FLAG_CAN_MULTI_CONN for shareable writable exports
-* 8.2: NBD_OPT_EXTENDED_HEADERS, NBD_FLAG_BLOCK_STATUS_PAYLOAD