btrfs: qgroup: Introduce function to find all new tree blocks of reloc tree
Introduce new function, qgroup_trace_new_subtree_blocks(), to iterate all new tree blocks in a reloc tree. So that qgroup could skip unrelated tree blocks during balance, which should hugely speedup balance speed when quota is enabled. The function qgroup_trace_new_subtree_blocks() itself only cares about new tree blocks in reloc tree. All its main works are: 1) Read out tree blocks according to parent pointers 2) Do recursive depth-first search Will call the same function on all its children tree blocks, with search level set to current level -1. And will also skip all children whose generation is smaller than @last_snapshot. 3) Call qgroup_trace_extent_swap() to trace tree blocks So although we have parameter list related to source file tree, it's not used at all, but only passed to qgroup_trace_extent_swap(). Thus despite the tree read code, the core should be pretty short and all about recursive depth-first search. Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>hifive-unleashed-5.1
Qu Wenruo
David Sterba
parent
25982561db
commit
ea49f3e73c
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@ -1874,6 +1874,141 @@ out:
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return ret;
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}
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/*
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* Helper function to do recursive generation-aware depth-first search, to
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* locate all new tree blocks in a subtree of reloc tree.
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*
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* E.g. (OO = Old tree blocks, NN = New tree blocks, whose gen == last_snapshot)
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* reloc tree
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* L2 NN (a)
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* / \
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* L1 OO NN (b)
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* / \ / \
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* L0 OO OO OO NN
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* (c) (d)
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* If we pass:
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* @dst_path = [ nodes[1] = NN(b), nodes[0] = NULL ],
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* @cur_level = 1
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* @root_level = 1
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*
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* We will iterate through tree blocks NN(b), NN(d) and info qgroup to trace
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* above tree blocks along with their counter parts in file tree.
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* While during search, old tree blocsk OO(c) will be skiped as tree block swap
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* won't affect OO(c).
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*/
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static int qgroup_trace_new_subtree_blocks(struct btrfs_trans_handle* trans,
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struct extent_buffer *src_eb,
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struct btrfs_path *dst_path,
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int cur_level, int root_level,
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u64 last_snapshot)
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{
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struct btrfs_fs_info *fs_info = trans->fs_info;
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struct extent_buffer *eb;
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bool need_cleanup = false;
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int ret = 0;
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int i;
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/* Level sanity check */
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if (cur_level < 0 || cur_level >= BTRFS_MAX_LEVEL ||
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root_level < 0 || root_level >= BTRFS_MAX_LEVEL ||
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root_level < cur_level) {
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btrfs_err_rl(fs_info,
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"%s: bad levels, cur_level=%d root_level=%d",
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__func__, cur_level, root_level);
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return -EUCLEAN;
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}
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/* Read the tree block if needed */
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if (dst_path->nodes[cur_level] == NULL) {
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struct btrfs_key first_key;
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int parent_slot;
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u64 child_gen;
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u64 child_bytenr;
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/*
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* dst_path->nodes[root_level] must be initialized before
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* calling this function.
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*/
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if (cur_level == root_level) {
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btrfs_err_rl(fs_info,
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"%s: dst_path->nodes[%d] not initialized, root_level=%d cur_level=%d",
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__func__, root_level, root_level, cur_level);
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return -EUCLEAN;
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}
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/*
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* We need to get child blockptr/gen from parent before we can
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* read it.
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*/
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eb = dst_path->nodes[cur_level + 1];
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parent_slot = dst_path->slots[cur_level + 1];
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child_bytenr = btrfs_node_blockptr(eb, parent_slot);
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child_gen = btrfs_node_ptr_generation(eb, parent_slot);
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btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
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/* This node is old, no need to trace */
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if (child_gen < last_snapshot)
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goto out;
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eb = read_tree_block(fs_info, child_bytenr, child_gen,
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cur_level, &first_key);
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if (IS_ERR(eb)) {
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ret = PTR_ERR(eb);
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goto out;
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} else if (!extent_buffer_uptodate(eb)) {
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free_extent_buffer(eb);
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ret = -EIO;
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goto out;
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}
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dst_path->nodes[cur_level] = eb;
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dst_path->slots[cur_level] = 0;
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btrfs_tree_read_lock(eb);
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btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
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dst_path->locks[cur_level] = BTRFS_READ_LOCK_BLOCKING;
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need_cleanup = true;
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}
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/* Now record this tree block and its counter part for qgroups */
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ret = qgroup_trace_extent_swap(trans, src_eb, dst_path, cur_level,
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root_level);
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if (ret < 0)
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goto cleanup;
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eb = dst_path->nodes[cur_level];
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if (cur_level > 0) {
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/* Iterate all child tree blocks */
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for (i = 0; i < btrfs_header_nritems(eb); i++) {
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/* Skip old tree blocks as they won't be swapped */
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if (btrfs_node_ptr_generation(eb, i) < last_snapshot)
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continue;
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dst_path->slots[cur_level] = i;
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/* Recursive call (at most 7 times) */
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ret = qgroup_trace_new_subtree_blocks(trans, src_eb,
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dst_path, cur_level - 1, root_level,
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last_snapshot);
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if (ret < 0)
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goto cleanup;
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}
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}
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cleanup:
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if (need_cleanup) {
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/* Clean up */
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btrfs_tree_unlock_rw(dst_path->nodes[cur_level],
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dst_path->locks[cur_level]);
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free_extent_buffer(dst_path->nodes[cur_level]);
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dst_path->nodes[cur_level] = NULL;
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dst_path->slots[cur_level] = 0;
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dst_path->locks[cur_level] = 0;
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}
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out:
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return ret;
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}
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int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
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struct extent_buffer *root_eb,
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u64 root_gen, int root_level)
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