On 27.11.18 г. 4:33 ч., Qu Wenruo wrote:
> Since btrfs-image is just restoring tree blocks without really check if
> that tree block contents makes sense, for multi-device image, block
> group items will keep that incorrect block group flags.
>
> For example, for a metadata RAID1 data RAID0 btrfs recovered to a single
> disk, its chunk tree will look like:
>
> item 1 key (FIRST_CHUNK_TREE CHUNK_ITEM 22020096)
> length 8388608 owner 2 stripe_len 65536 type SYSTEM
> item 2 key (FIRST_CHUNK_TREE CHUNK_ITEM 30408704)
> length 1073741824 owner 2 stripe_len 65536 type METADATA
> item 3 key (FIRST_CHUNK_TREE CHUNK_ITEM 1104150528)
> length 1073741824 owner 2 stripe_len 65536 type DATA
>
> All chunks have correct type (SINGLE).
>
> While its block group items will look like:
>
> item 1 key (22020096 BLOCK_GROUP_ITEM 8388608)
> block group used 16384 chunk_objectid 256 flags SYSTEM|RAID1
> item 3 key (30408704 BLOCK_GROUP_ITEM 1073741824)
> block group used 114688 chunk_objectid 256 flags METADATA|RAID1
> item 11 key (1104150528 BLOCK_GROUP_ITEM 1073741824)
> block group used 1572864 chunk_objectid 256 flags DATA|RAID0
>
> All block group items still have the wrong profiles.
>
> And btrfs check (lowmem mode for better output) will report error for such image:
>
> ERROR: chunk[22020096 30408704) related block group item flags mismatch, wanted: 2, have: 18
> ERROR: chunk[30408704 1104150528) related block group item flags mismatch, wanted: 4, have: 20
> ERROR: chunk[1104150528 2177892352) related block group item flags mismatch, wanted: 1, have: 9
>
> This patch will do an extra repair for block group items to fix the
> profile of them.
>
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
> ---
> image/main.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 47 insertions(+)
>
> diff --git a/image/main.c b/image/main.c
> index 36b5c95ea146..9060f6b1b665 100644
> --- a/image/main.c
> +++ b/image/main.c
> @@ -2164,6 +2164,52 @@ again:
> return 0;
> }
>
> +static void fixup_block_groups(struct btrfs_trans_handle *trans,
> + struct btrfs_fs_info *fs_info)
You are not even using the trans handle in this function, why pass it?
> +{
> + struct btrfs_block_group_cache *bg;
> + struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
> + struct cache_extent *ce;
> + struct map_lookup *map;
> + u64 extra_flags;
> +
> + for (ce = search_cache_extent(&map_tree->cache_tree, 0); ce;
> + ce = next_cache_extent(ce)) {
> + map = container_of(ce, struct map_lookup, ce);
> +
> + bg = btrfs_lookup_block_group(fs_info, ce->start);
> + if (!bg) {
> + warning(
> + "can't find block group %llu, result fs may not be mountable",
> + ce->start);
> + continue;
> + }
> + extra_flags = map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK;
> +
> + if (bg->flags == map->type)
> + continue;
> +
> + /* Update the block group item and mark the bg dirty */
> + bg->flags = map->type;
> + btrfs_set_block_group_flags(&bg->item, bg->flags);
> + set_extent_bits(&fs_info->block_group_cache, ce->start,
> + ce->start + ce->size - 1, BLOCK_GROUP_DIRTY);
> +
> + /*
> + * Chunk and bg flags can be different, changing bg flags
> + * without update avail_data/meta_alloc_bits will lead to
> + * ENOSPC.
> + * So here we set avail_*_alloc_bits to match chunk types.
> + */
> + if (map->type & BTRFS_BLOCK_GROUP_DATA)
> + fs_info->avail_data_alloc_bits = extra_flags;
> + if (map->type & BTRFS_BLOCK_GROUP_METADATA)
> + fs_info->avail_metadata_alloc_bits = extra_flags;
> + if (map->type & BTRFS_BLOCK_GROUP_SYSTEM)
> + fs_info->avail_system_alloc_bits = extra_flags;
> + }
> +}
> +
> static int fixup_chunks_and_devices(struct btrfs_fs_info *fs_info,
> struct mdrestore_struct *mdres, off_t dev_size)
> {
> @@ -2180,6 +2226,7 @@ static int fixup_chunks_and_devices(struct btrfs_fs_info *fs_info,
> return PTR_ERR(trans);
> }
>
> + fixup_block_groups(trans, fs_info);
> ret = fixup_device_size(trans, fs_info, mdres, dev_size);
> if (ret < 0)
> goto error;
>
