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David Alan Gilbert" , Peter Krempa , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 7/22/20 3:05 AM, Max Reitz wrote: > This migration parameter allows mapping block node names and bitmap > names to aliases for the purpose of block dirty bitmap migration. > > This way, management tools can use different node and bitmap names on > the source and destination and pass the mapping of how bitmaps are to be > transferred to qemu (on the source, the destination, or even both with > arbitrary aliases in the migration stream). > > Suggested-by: Vladimir Sementsov-Ogievskiy > Signed-off-by: Max Reitz > --- > qapi/migration.json | 104 ++++++++- > migration/migration.h | 3 + > migration/block-dirty-bitmap.c | 373 ++++++++++++++++++++++++++++----- > migration/migration.c | 30 +++ > monitor/hmp-cmds.c | 30 +++ > 5 files changed, 485 insertions(+), 55 deletions(-) > > diff --git a/qapi/migration.json b/qapi/migration.json > index d5000558c6..d7e953cd73 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -507,6 +507,44 @@ > 'data': [ 'none', 'zlib', > { 'name': 'zstd', 'if': 'defined(CONFIG_ZSTD)' } ] } > > +## > +# @BitmapMigrationBitmapAlias: > +# > +# @name: The name of the bitmap. > +# > +# @alias: An alias name for migration (for example the bitmap name on > +# the opposite site). > +# > +# Since: 5.1 5.2, now, but I can touch that up if it is the only problem raised. > +# @block-bitmap-mapping: Maps block nodes and bitmaps on them to > +# aliases for the purpose of dirty bitmap migration. Such > +# aliases may for example be the corresponding names on the > +# opposite site. > +# The mapping must be one-to-one, and on the destination also > +# complete: On the source, bitmaps on nodes where either the > +# bitmap or the node is not mapped will be ignored. In > +# contrast, on the destination, receiving a bitmap (by alias) > +# from a node (by alias) when either alias is not mapped will > +# result in an error. Grammar is a bit odd and it feels repetitive. How about: The mapping must not provide more than one alias for a bitmap, nor reuse the same alias across multiple bitmaps in the same node. On the source, an omitted node or bitmap within a node will ignore those bitmaps. In contrast, on the destination, receiving a bitmap (by alias) from a node (by alias) when either alias is not mapped will result in an error. > +# Note that the destination does not know about bitmaps it > +# does not receive, so there is no limitation or requirement > +# regarding the number of bitmaps received, or how they are > +# named, or on which nodes they are placed. > +# By default (when this parameter has never been set), bitmap > +# names are mapped to themselves. Nodes are mapped to their > +# block device name if there is one, and to their node name > +# otherwise. (Since 5.2) Looks good. > @@ -781,6 +839,25 @@ > # will consume more CPU. > # Defaults to 1. (Since 5.0) > # > +# @block-bitmap-mapping: Maps block nodes and bitmaps on them to > +# aliases for the purpose of dirty bitmap migration. Such > +# aliases may for example be the corresponding names on the > +# opposite site. Ah, the joys of duplicated text. > +++ b/migration/block-dirty-bitmap.c > @@ -128,7 +131,8 @@ typedef struct DirtyBitmapMigState { > > typedef struct DirtyBitmapLoadState { > uint32_t flags; > - char node_name[256]; > + char node_alias[256]; > + char bitmap_alias[256]; Do we properly check that alias names will never overflow? > +static GHashTable *construct_alias_map(const BitmapMigrationNodeAliasList *bbm, > + bool name_to_alias, > + Error **errp) > +{ > + GHashTable *alias_map; > + > + alias_map = g_hash_table_new_full(g_str_hash, g_str_equal, > + g_free, free_alias_map_inner_node); > + > + for (; bbm; bbm = bbm->next) { > + const BitmapMigrationNodeAlias *bmna = bbm->value; > + const BitmapMigrationBitmapAliasList *bmbal; > + AliasMapInnerNode *amin; > + GHashTable *bitmaps_map; > + const char *node_map_from, *node_map_to; > + > + if (!id_wellformed(bmna->alias)) { > + error_setg(errp, "The node alias %s is not well-formed", > + bmna->alias); > + goto fail; > + } Maybe id_wellformed should enforce lengths? Otherwise, I'm not seeing a length limit applied during the mapping process. Modulo that, I think we're ready to go. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org