Introduce a new function, btrfs_check_extent_exists(), to check if there is any extent in the range specified by user.
The parameter can be a large range, and if any extent exists in the range, it will return >0 (in fact it will return 1). Or return 0 if no extent is found. Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com> --- ctree.h | 2 ++ extent-tree.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 62 insertions(+) diff --git a/ctree.h b/ctree.h index 9c999b1f..d3ddf752 100644 --- a/ctree.h +++ b/ctree.h @@ -2541,6 +2541,8 @@ int exclude_super_stripes(struct btrfs_root *root, u64 add_new_free_space(struct btrfs_block_group_cache *block_group, struct btrfs_fs_info *info, u64 start, u64 end); u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset); +int btrfs_check_extent_exists(struct btrfs_fs_info *fs_info, u64 start, + u64 len); /* ctree.c */ int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2); diff --git a/extent-tree.c b/extent-tree.c index b12ee290..17c2c10e 100644 --- a/extent-tree.c +++ b/extent-tree.c @@ -4258,3 +4258,63 @@ u64 add_new_free_space(struct btrfs_block_group_cache *block_group, return total_added; } + +/* + * Check if there is any extent(both data and metadata) in the range + * [@start, @start + @len) + * + * Return 0 for no extent found. + * Return >0 for found extent. + * Return <0 for fatal error. + */ +int btrfs_check_extent_exists(struct btrfs_fs_info *fs_info, u64 start, + u64 len) +{ + struct btrfs_path *path; + struct btrfs_key key; + u64 extent_start; + u64 extent_len; + int ret; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + key.objectid = start + len; + key.type = 0; + key.offset = 0; + + ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0); + if (ret < 0) + goto out; + /* + * Now we're pointing at slot whose key.object >= end, skip to previous + * extent. + */ + ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0); + if (ret < 0) + goto out; + if (ret > 0) { + ret = 0; + goto out; + } + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); + extent_start = key.objectid; + if (key.type == BTRFS_METADATA_ITEM_KEY) + extent_len = fs_info->extent_root->nodesize; + else + extent_len = key.offset; + + /* + * search_slot() and previous_extent_item() has ensured that our + * extent_start < start + len, we only need to care extent end. + */ + if (extent_start + extent_len <= start) + ret = 0; + else + ret = 1; + +out: + btrfs_free_path(path); + return ret; +} -- 2.13.0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html