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From ae2c3df00d673d436fe4d8ec9103a3b76d7e6233 Mon Sep 17 00:00:00 2001
From: Hanna Reitz <hreitz@redhat.com>
Date: Mon, 20 Jun 2022 18:26:58 +0200
Subject: [PATCH 11/20] block/qapi: Let bdrv_query_image_info() recurse
RH-Author: Hanna Czenczek <hreitz@redhat.com>
RH-MergeRequest: 145: Show protocol-level information in qemu-img info
RH-Bugzilla: 1860292
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Stefano Garzarella <sgarzare@redhat.com>
RH-Commit: [6/12] 451a83fd682cd6dd6026c22974d18c2f12ee06e3 (hreitz/qemu-kvm-c-9-s)
There is no real reason why bdrv_query_image_info() should generally not
recurse. The ImageInfo struct has a pointer to the backing image, so it
should generally be filled, unless the caller explicitly opts out.
This moves the recursing code from bdrv_block_device_info() into
bdrv_query_image_info().
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220620162704.80987-7-hreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 5d8813593f3f673fc96eed199beb35690cc46f58)
Conflicts:
block/qapi.c: Conflicts with
54fde4ff0621c22b15cbaaa3c74301cc0dbd1c9e ("qapi block: Elide
redundant has_FOO in generated C"), which dropped
`has_backing_image`. Without that commit (and 44ea9d9be before it),
we still need to set `has_backing_image` in
`bdrv_query_image_info()`.
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
---
block/qapi.c | 94 +++++++++++++++++++++++++++-----------------
include/block/qapi.h | 2 +
2 files changed, 59 insertions(+), 37 deletions(-)
diff --git a/block/qapi.c b/block/qapi.c
index ad88bf9b38..5d0a8d2ce3 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -47,8 +47,10 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
Error **errp)
{
ImageInfo **p_image_info;
+ ImageInfo *backing_info;
BlockDriverState *bs0, *backing;
BlockDeviceInfo *info;
+ ERRP_GUARD();
if (!bs->drv) {
error_setg(errp, "Block device %s is ejected", bs->node_name);
@@ -149,38 +151,21 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
bs0 = bs;
p_image_info = &info->image;
info->backing_file_depth = 0;
- while (1) {
- Error *local_err = NULL;
- bdrv_query_image_info(bs0, p_image_info, &local_err);
- if (local_err) {
- error_propagate(errp, local_err);
- qapi_free_BlockDeviceInfo(info);
- return NULL;
- }
-
- /* stop gathering data for flat output */
- if (flat) {
- break;
- }
- if (bs0->drv && bdrv_filter_or_cow_child(bs0)) {
- /*
- * Put any filtered child here (for backwards compatibility to when
- * we put bs0->backing here, which might be any filtered child).
- */
- info->backing_file_depth++;
- bs0 = bdrv_filter_or_cow_bs(bs0);
- (*p_image_info)->has_backing_image = true;
- p_image_info = &((*p_image_info)->backing_image);
- } else {
- break;
- }
+ /*
+ * Skip automatically inserted nodes that the user isn't aware of for
+ * query-block (blk != NULL), but not for query-named-block-nodes
+ */
+ bdrv_query_image_info(bs0, p_image_info, flat, blk != NULL, errp);
+ if (*errp) {
+ qapi_free_BlockDeviceInfo(info);
+ return NULL;
+ }
- /* Skip automatically inserted nodes that the user isn't aware of for
- * query-block (blk != NULL), but not for query-named-block-nodes */
- if (blk) {
- bs0 = bdrv_skip_implicit_filters(bs0);
- }
+ backing_info = info->image->backing_image;
+ while (backing_info) {
+ info->backing_file_depth++;
+ backing_info = backing_info->backing_image;
}
return info;
@@ -363,19 +348,28 @@ void bdrv_query_block_node_info(BlockDriverState *bs,
* bdrv_query_image_info:
* @bs: block node to examine
* @p_info: location to store image information
+ * @flat: skip backing node information
+ * @skip_implicit_filters: skip implicit filters in the backing chain
* @errp: location to store error information
*
- * Store "flat" image information in @p_info.
+ * Store image information in @p_info, potentially recursively covering the
+ * backing chain.
*
- * "Flat" means it does *not* query backing image information,
- * i.e. (*pinfo)->has_backing_image will be set to false and
- * (*pinfo)->backing_image to NULL even when the image does in fact have
- * a backing image.
+ * If @flat is true, do not query backing image information, i.e.
+ * (*p_info)->has_backing_image will be set to false and
+ * (*p_info)->backing_image to NULL even when the image does in fact have a
+ * backing image.
+ *
+ * If @skip_implicit_filters is true, implicit filter nodes in the backing chain
+ * will be skipped when querying backing image information.
+ * (@skip_implicit_filters is ignored when @flat is true.)
*
* @p_info will be set only on success. On error, store error in @errp.
*/
void bdrv_query_image_info(BlockDriverState *bs,
ImageInfo **p_info,
+ bool flat,
+ bool skip_implicit_filters,
Error **errp)
{
ImageInfo *info;
@@ -384,11 +378,37 @@ void bdrv_query_image_info(BlockDriverState *bs,
info = g_new0(ImageInfo, 1);
bdrv_do_query_node_info(bs, qapi_ImageInfo_base(info), errp);
if (*errp) {
- qapi_free_ImageInfo(info);
- return;
+ goto fail;
+ }
+
+ if (!flat) {
+ BlockDriverState *backing;
+
+ /*
+ * Use any filtered child here (for backwards compatibility to when
+ * we always took bs->backing, which might be any filtered child).
+ */
+ backing = bdrv_filter_or_cow_bs(bs);
+ if (skip_implicit_filters) {
+ backing = bdrv_skip_implicit_filters(backing);
+ }
+
+ if (backing) {
+ bdrv_query_image_info(backing, &info->backing_image, false,
+ skip_implicit_filters, errp);
+ if (*errp) {
+ goto fail;
+ }
+ info->has_backing_image = true;
+ }
}
*p_info = info;
+ return;
+
+fail:
+ assert(*errp);
+ qapi_free_ImageInfo(info);
}
/* @p_info will be set only on success. */
diff --git a/include/block/qapi.h b/include/block/qapi.h
index 22198dcd0c..2174bf8fa2 100644
--- a/include/block/qapi.h
+++ b/include/block/qapi.h
@@ -40,6 +40,8 @@ void bdrv_query_block_node_info(BlockDriverState *bs,
Error **errp);
void bdrv_query_image_info(BlockDriverState *bs,
ImageInfo **p_info,
+ bool flat,
+ bool skip_implicit_filters,
Error **errp);
void bdrv_snapshot_dump(QEMUSnapshotInfo *sn);
--
2.31.1
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