From 1ac2f161e5585d1ed71b79e8279c9d78b2efe35e Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Mon, 17 Sep 2018 07:48:43 +0200
Subject: [PATCH 01/49] commit: Add top-node/base-node options

RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <20180911130704.6641-2-kwolf@redhat.com>
Patchwork-id: 82114
O-Subject: [RHV-7.6 qemu-kvm-rhev PATCH 1/2] commit: Add top-node/base-node options
Bugzilla: 1624012
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>

The block-commit QMP command required specifying the top and base nodes
of the commit jobs using the file name of that node. While this works
in simple cases (local files with absolute paths), the file names
generated for more complicated setups can be hard to predict.

The block-commit command has more problems than just this, so we want to
replace it altogether in the long run, but libvirt needs a reliable way
to address nodes now. So we don't want to wait for a new, cleaner
command, but just add the minimal thing needed right now.

This adds two new options top-node and base-node to the command, which
allow specifying node names instead. They are mutually exclusive with
the old options.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c           | 32 ++++++++++++++++++++++++++++++--
 qapi/block-core.json | 24 ++++++++++++++++++------
 2 files changed, 48 insertions(+), 8 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 0eb6bba..fb355c8 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3371,7 +3371,9 @@ out:
 }
 
 void qmp_block_commit(bool has_job_id, const char *job_id, const char *device,
+                      bool has_base_node, const char *base_node,
                       bool has_base, const char *base,
+                      bool has_top_node, const char *top_node,
                       bool has_top, const char *top,
                       bool has_backing_file, const char *backing_file,
                       bool has_speed, int64_t speed,
@@ -3432,7 +3434,20 @@ void qmp_block_commit(bool has_job_id, const char *job_id, const char *device,
     /* default top_bs is the active layer */
     top_bs = bs;
 
-    if (has_top && top) {
+    if (has_top_node && has_top) {
+        error_setg(errp, "'top-node' and 'top' are mutually exclusive");
+        goto out;
+    } else if (has_top_node) {
+        top_bs = bdrv_lookup_bs(NULL, top_node, errp);
+        if (top_bs == NULL) {
+            goto out;
+        }
+        if (!bdrv_chain_contains(bs, top_bs)) {
+            error_setg(errp, "'%s' is not in this backing file chain",
+                       top_node);
+            goto out;
+        }
+    } else if (has_top && top) {
         if (strcmp(bs->filename, top) != 0) {
             top_bs = bdrv_find_backing_image(bs, top);
         }
@@ -3445,7 +3460,20 @@ void qmp_block_commit(bool has_job_id, const char *job_id, const char *device,
 
     assert(bdrv_get_aio_context(top_bs) == aio_context);
 
-    if (has_base && base) {
+    if (has_base_node && has_base) {
+        error_setg(errp, "'base-node' and 'base' are mutually exclusive");
+        goto out;
+    } else if (has_base_node) {
+        base_bs = bdrv_lookup_bs(NULL, base_node, errp);
+        if (base_bs == NULL) {
+            goto out;
+        }
+        if (!bdrv_chain_contains(top_bs, base_bs)) {
+            error_setg(errp, "'%s' is not in this backing file chain",
+                       base_node);
+            goto out;
+        }
+    } else if (has_base && base) {
         base_bs = bdrv_find_backing_image(top_bs, base);
     } else {
         base_bs = bdrv_find_base(top_bs);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 56937db..8da07cd 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1440,12 +1440,23 @@
 #
 # @device:  the device name or node-name of a root node
 #
-# @base:   The file name of the backing image to write data into.
-#                    If not specified, this is the deepest backing image.
+# @base-node: The node name of the backing image to write data into.
+#             If not specified, this is the deepest backing image.
+#             (since: 3.1)
 #
-# @top:    The file name of the backing image within the image chain,
-#                    which contains the topmost data to be committed down. If
-#                    not specified, this is the active layer.
+# @base: Same as @base-node, except that it is a file name rather than a node
+#        name. This must be the exact filename string that was used to open the
+#        node; other strings, even if addressing the same file, are not
+#        accepted (deprecated, use @base-node instead)
+#
+# @top-node: The node name of the backing image within the image chain
+#            which contains the topmost data to be committed down. If
+#            not specified, this is the active layer. (since: 3.1)
+#
+# @top: Same as @top-node, except that it is a file name rather than a node
+#       name. This must be the exact filename string that was used to open the
+#       node; other strings, even if addressing the same file, are not
+#       accepted (deprecated, use @base-node instead)
 #
 # @backing-file:  The backing file string to write into the overlay
 #                           image of 'top'.  If 'top' is the active layer,
@@ -1514,7 +1525,8 @@
 #
 ##
 { 'command': 'block-commit',
-  'data': { '*job-id': 'str', 'device': 'str', '*base': 'str', '*top': 'str',
+  'data': { '*job-id': 'str', 'device': 'str', '*base-node': 'str',
+            '*base': 'str', '*top-node': 'str', '*top': 'str',
             '*backing-file': 'str', '*speed': 'int',
             '*filter-node-name': 'str',
             '*auto-finalize': 'bool', '*auto-dismiss': 'bool' } }
-- 
1.8.3.1