btrfs: Introduce mount time chunk <-> dev extent mapping check
This patch will introduce chunk <-> dev extent mapping check, to protect us against invalid dev extents or chunks. Since chunk mapping is the fundamental infrastructure of btrfs, extra check at mount time could prevent a lot of unexpected behavior (BUG_ON). Reported-by: Xu Wen <wen.xu@gatech.edu> Link: https://bugzilla.kernel.org/show_bug.cgi?id=200403 Link: https://bugzilla.kernel.org/show_bug.cgi?id=200407 Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Su Yue <suy.fnst@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo
David Sterba
parent
7ef49515fa
commit
cf90d884b3
3 changed files with 193 additions and 0 deletions
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@ -3030,6 +3030,13 @@ int open_ctree(struct super_block *sb,
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fs_info->generation = generation;
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fs_info->last_trans_committed = generation;
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ret = btrfs_verify_dev_extents(fs_info);
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if (ret) {
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btrfs_err(fs_info,
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"failed to verify dev extents against chunks: %d",
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ret);
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goto fail_block_groups;
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}
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ret = btrfs_recover_balance(fs_info);
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if (ret) {
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btrfs_err(fs_info, "failed to recover balance: %d", ret);
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@ -6452,6 +6452,7 @@ static int read_one_chunk(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
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map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
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map->type = btrfs_chunk_type(leaf, chunk);
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map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
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map->verified_stripes = 0;
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for (i = 0; i < num_stripes; i++) {
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map->stripes[i].physical =
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btrfs_stripe_offset_nr(leaf, chunk, i);
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@ -7318,3 +7319,186 @@ int btrfs_bg_type_to_factor(u64 flags)
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return 2;
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return 1;
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}
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static u64 calc_stripe_length(u64 type, u64 chunk_len, int num_stripes)
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{
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int index = btrfs_bg_flags_to_raid_index(type);
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int ncopies = btrfs_raid_array[index].ncopies;
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int data_stripes;
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switch (type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
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case BTRFS_BLOCK_GROUP_RAID5:
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data_stripes = num_stripes - 1;
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break;
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case BTRFS_BLOCK_GROUP_RAID6:
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data_stripes = num_stripes - 2;
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break;
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default:
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data_stripes = num_stripes / ncopies;
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break;
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}
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return div_u64(chunk_len, data_stripes);
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}
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static int verify_one_dev_extent(struct btrfs_fs_info *fs_info,
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u64 chunk_offset, u64 devid,
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u64 physical_offset, u64 physical_len)
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{
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struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
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struct extent_map *em;
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struct map_lookup *map;
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u64 stripe_len;
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bool found = false;
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int ret = 0;
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int i;
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read_lock(&em_tree->lock);
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em = lookup_extent_mapping(em_tree, chunk_offset, 1);
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read_unlock(&em_tree->lock);
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if (!em) {
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btrfs_err(fs_info,
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"dev extent physical offset %llu on devid %llu doesn't have corresponding chunk",
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physical_offset, devid);
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ret = -EUCLEAN;
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goto out;
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}
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map = em->map_lookup;
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stripe_len = calc_stripe_length(map->type, em->len, map->num_stripes);
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if (physical_len != stripe_len) {
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btrfs_err(fs_info,
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"dev extent physical offset %llu on devid %llu length doesn't match chunk %llu, have %llu expect %llu",
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physical_offset, devid, em->start, physical_len,
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stripe_len);
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ret = -EUCLEAN;
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goto out;
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}
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for (i = 0; i < map->num_stripes; i++) {
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if (map->stripes[i].dev->devid == devid &&
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map->stripes[i].physical == physical_offset) {
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found = true;
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if (map->verified_stripes >= map->num_stripes) {
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btrfs_err(fs_info,
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"too many dev extents for chunk %llu found",
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em->start);
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ret = -EUCLEAN;
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goto out;
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}
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map->verified_stripes++;
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break;
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}
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}
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if (!found) {
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btrfs_err(fs_info,
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"dev extent physical offset %llu devid %llu has no corresponding chunk",
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physical_offset, devid);
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ret = -EUCLEAN;
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}
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out:
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free_extent_map(em);
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return ret;
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}
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static int verify_chunk_dev_extent_mapping(struct btrfs_fs_info *fs_info)
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{
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struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
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struct extent_map *em;
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struct rb_node *node;
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int ret = 0;
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read_lock(&em_tree->lock);
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for (node = rb_first(&em_tree->map); node; node = rb_next(node)) {
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em = rb_entry(node, struct extent_map, rb_node);
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if (em->map_lookup->num_stripes !=
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em->map_lookup->verified_stripes) {
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btrfs_err(fs_info,
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"chunk %llu has missing dev extent, have %d expect %d",
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em->start, em->map_lookup->verified_stripes,
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em->map_lookup->num_stripes);
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ret = -EUCLEAN;
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goto out;
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}
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}
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out:
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read_unlock(&em_tree->lock);
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return ret;
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}
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/*
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* Ensure that all dev extents are mapped to correct chunk, otherwise
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* later chunk allocation/free would cause unexpected behavior.
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*
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* NOTE: This will iterate through the whole device tree, which should be of
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* the same size level as the chunk tree. This slightly increases mount time.
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*/
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int btrfs_verify_dev_extents(struct btrfs_fs_info *fs_info)
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{
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struct btrfs_path *path;
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struct btrfs_root *root = fs_info->dev_root;
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struct btrfs_key key;
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int ret = 0;
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key.objectid = 1;
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key.type = BTRFS_DEV_EXTENT_KEY;
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key.offset = 0;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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path->reada = READA_FORWARD;
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ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
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if (ret < 0)
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goto out;
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if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
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ret = btrfs_next_item(root, path);
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if (ret < 0)
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goto out;
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/* No dev extents at all? Not good */
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if (ret > 0) {
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ret = -EUCLEAN;
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goto out;
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}
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}
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while (1) {
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struct extent_buffer *leaf = path->nodes[0];
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struct btrfs_dev_extent *dext;
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int slot = path->slots[0];
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u64 chunk_offset;
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u64 physical_offset;
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u64 physical_len;
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u64 devid;
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btrfs_item_key_to_cpu(leaf, &key, slot);
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if (key.type != BTRFS_DEV_EXTENT_KEY)
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break;
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devid = key.objectid;
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physical_offset = key.offset;
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dext = btrfs_item_ptr(leaf, slot, struct btrfs_dev_extent);
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chunk_offset = btrfs_dev_extent_chunk_offset(leaf, dext);
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physical_len = btrfs_dev_extent_length(leaf, dext);
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ret = verify_one_dev_extent(fs_info, chunk_offset, devid,
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physical_offset, physical_len);
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if (ret < 0)
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goto out;
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ret = btrfs_next_item(root, path);
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if (ret < 0)
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goto out;
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if (ret > 0) {
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ret = 0;
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break;
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}
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}
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/* Ensure all chunks have corresponding dev extents */
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ret = verify_chunk_dev_extent_mapping(fs_info);
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out:
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btrfs_free_path(path);
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return ret;
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}
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@ -345,6 +345,7 @@ struct map_lookup {
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u64 stripe_len;
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int num_stripes;
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int sub_stripes;
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int verified_stripes; /* For mount time dev extent verification */
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struct btrfs_bio_stripe stripes[];
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};
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@ -556,5 +557,6 @@ bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,
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struct btrfs_device *failing_dev);
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int btrfs_bg_type_to_factor(u64 flags);
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int btrfs_verify_dev_extents(struct btrfs_fs_info *fs_info);
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#endif
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