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
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