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Btrfs: recursion free-first pass
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
parent
0579da4280
commit
20524f0226
2 changed files with 100 additions and 3 deletions
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@ -50,7 +50,7 @@ static int inc_block_ref(struct ctree_root *root, u64 blocknr)
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return 0;
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}
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static int lookup_block_ref(struct ctree_root *root, u64 blocknr, int *refs)
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static int lookup_block_ref(struct ctree_root *root, u64 blocknr, u32 *refs)
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{
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struct ctree_path path;
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int ret;
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@ -415,6 +415,100 @@ struct tree_buffer *alloc_free_block(struct ctree_root *root)
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return buf;
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}
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int walk_down_tree(struct ctree_root *root, struct ctree_path *path, int *level)
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{
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struct tree_buffer *next;
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struct tree_buffer *cur;
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u64 blocknr;
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int ret;
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u32 refs;
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ret = lookup_block_ref(root, path->nodes[*level]->blocknr, &refs);
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BUG_ON(ret);
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if (refs > 1)
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goto out;
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while(*level > 0) {
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cur = path->nodes[*level];
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if (path->slots[*level] >= cur->node.header.nritems)
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break;
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blocknr = cur->node.blockptrs[path->slots[*level]];
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ret = lookup_block_ref(root, blocknr, &refs);
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if (refs != 1 || *level == 1) {
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path->slots[*level]++;
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ret = free_extent(root, blocknr, 1);
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BUG_ON(ret);
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continue;
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}
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BUG_ON(ret);
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next = read_tree_block(root, blocknr);
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if (path->nodes[*level-1]) {
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tree_block_release(root, path->nodes[*level-1]);
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}
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path->nodes[*level-1] = next;
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*level = node_level(next->node.header.flags);
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path->slots[*level] = 0;
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}
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out:
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ret = free_extent(root, path->nodes[*level]->blocknr, 1);
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path->nodes[*level] = NULL;
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*level += 1;
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BUG_ON(ret);
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return 0;
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}
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int walk_up_tree(struct ctree_root *root, struct ctree_path *path, int *level)
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{
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int i;
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int slot;
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int ret;
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for(i = *level; i < MAX_LEVEL - 1 && path->nodes[i]; i++) {
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slot = path->slots[i];
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if (slot < path->nodes[i]->node.header.nritems - 1) {
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path->slots[i]++;
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*level = i;
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return 0;
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} else {
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ret = free_extent(root,
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path->nodes[*level]->blocknr, 1);
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*level = i + 1;
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BUG_ON(ret);
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}
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}
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return 1;
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}
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int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
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{
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int ret;
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int level;
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struct ctree_path path;
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int i;
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int orig_level;
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init_path(&path);
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level = node_level(snap->node.header.flags);
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orig_level = level;
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path.nodes[level] = snap;
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path.slots[level] = 0;
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while(1) {
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ret = walk_down_tree(root, &path, &level);
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if (ret > 0)
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break;
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ret = walk_up_tree(root, &path, &level);
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if (ret > 0)
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break;
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}
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for (i = 0; i < orig_level; i++) {
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if (path.nodes[i])
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tree_block_release(root, path.nodes[i]);
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}
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return 0;
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}
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#if 0
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int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
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{
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int ret;
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@ -441,4 +535,4 @@ int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
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BUG_ON(ret);
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return 0;
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}
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#endif
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@ -9,7 +9,7 @@
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/* for testing only */
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int next_key(int i, int max_key) {
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return rand() % max_key;
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//return i;
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// return i;
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}
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int main(int ac, char **av) {
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@ -44,6 +44,9 @@ int main(int ac, char **av) {
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if (!ret)
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tree_size++;
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free(buf);
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if (i == run_size - 5) {
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commit_transaction(root, &super);
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}
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}
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close_ctree(root, &super);
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