From ae2c3df00d673d436fe4d8ec9103a3b76d7e6233 Mon Sep 17 00:00:00 2001 From: Hanna Reitz 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 RH-MergeRequest: 145: Show protocol-level information in qemu-img info RH-Bugzilla: 1860292 RH-Acked-by: Kevin Wolf RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Stefano Garzarella 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 Message-Id: <20220620162704.80987-7-hreitz@redhat.com> Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf (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 --- 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