btrfs: move functions for tree compare to send.c

Send is the only user of tree_compare, we can move it there along with
the other helpers and definitions.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 0 insertions, 362 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 3b585f3e4d11..fbf94e28fba8 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -5246,368 +5246,6 @@ out:
 	return ret;
 }
 
-static int tree_move_down(struct btrfs_path *path, int *level)
-{
-	struct extent_buffer *eb;
-
-	BUG_ON(*level == 0);
-	eb = btrfs_read_node_slot(path->nodes[*level], path->slots[*level]);
-	if (IS_ERR(eb))
-		return PTR_ERR(eb);
-
-	path->nodes[*level - 1] = eb;
-	path->slots[*level - 1] = 0;
-	(*level)--;
-	return 0;
-}
-
-static int tree_move_next_or_upnext(struct btrfs_path *path,
-				    int *level, int root_level)
-{
-	int ret = 0;
-	int nritems;
-	nritems = btrfs_header_nritems(path->nodes[*level]);
-
-	path->slots[*level]++;
-
-	while (path->slots[*level] >= nritems) {
-		if (*level == root_level)
-			return -1;
-
-		/* move upnext */
-		path->slots[*level] = 0;
-		free_extent_buffer(path->nodes[*level]);
-		path->nodes[*level] = NULL;
-		(*level)++;
-		path->slots[*level]++;
-
-		nritems = btrfs_header_nritems(path->nodes[*level]);
-		ret = 1;
-	}
-	return ret;
-}
-
-/*
- * Returns 1 if it had to move up and next. 0 is returned if it moved only next
- * or down.
- */
-static int tree_advance(struct btrfs_path *path,
-			int *level, int root_level,
-			int allow_down,
-			struct btrfs_key *key)
-{
-	int ret;
-
-	if (*level == 0 || !allow_down) {
-		ret = tree_move_next_or_upnext(path, level, root_level);
-	} else {
-		ret = tree_move_down(path, level);
-	}
-	if (ret >= 0) {
-		if (*level == 0)
-			btrfs_item_key_to_cpu(path->nodes[*level], key,
-					path->slots[*level]);
-		else
-			btrfs_node_key_to_cpu(path->nodes[*level], key,
-					path->slots[*level]);
-	}
-	return ret;
-}
-
-static int tree_compare_item(struct btrfs_path *left_path,
-			     struct btrfs_path *right_path,
-			     char *tmp_buf)
-{
-	int cmp;
-	int len1, len2;
-	unsigned long off1, off2;
-
-	len1 = btrfs_item_size_nr(left_path->nodes[0], left_path->slots[0]);
-	len2 = btrfs_item_size_nr(right_path->nodes[0], right_path->slots[0]);
-	if (len1 != len2)
-		return 1;
-
-	off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]);
-	off2 = btrfs_item_ptr_offset(right_path->nodes[0],
-				right_path->slots[0]);
-
-	read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1);
-
-	cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1);
-	if (cmp)
-		return 1;
-	return 0;
-}
-
-#define ADVANCE 1
-#define ADVANCE_ONLY_NEXT -1
-
-/*
- * This function compares two trees and calls the provided callback for
- * every changed/new/deleted item it finds.
- * If shared tree blocks are encountered, whole subtrees are skipped, making
- * the compare pretty fast on snapshotted subvolumes.
- *
- * This currently works on commit roots only. As commit roots are read only,
- * we don't do any locking. The commit roots are protected with transactions.
- * Transactions are ended and rejoined when a commit is tried in between.
- *
- * This function checks for modifications done to the trees while comparing.
- * If it detects a change, it aborts immediately.
- */
-int btrfs_compare_trees(struct btrfs_root *left_root,
-			struct btrfs_root *right_root,
-			btrfs_changed_cb_t changed_cb, void *ctx)
-{
-	struct btrfs_fs_info *fs_info = left_root->fs_info;
-	int ret;
-	int cmp;
-	struct btrfs_path *left_path = NULL;
-	struct btrfs_path *right_path = NULL;
-	struct btrfs_key left_key;
-	struct btrfs_key right_key;
-	char *tmp_buf = NULL;
-	int left_root_level;
-	int right_root_level;
-	int left_level;
-	int right_level;
-	int left_end_reached;
-	int right_end_reached;
-	int advance_left;
-	int advance_right;
-	u64 left_blockptr;
-	u64 right_blockptr;
-	u64 left_gen;
-	u64 right_gen;
-
-	left_path = btrfs_alloc_path();
-	if (!left_path) {
-		ret = -ENOMEM;
-		goto out;
-	}
-	right_path = btrfs_alloc_path();
-	if (!right_path) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	tmp_buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
-	if (!tmp_buf) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	left_path->search_commit_root = 1;
-	left_path->skip_locking = 1;
-	right_path->search_commit_root = 1;
-	right_path->skip_locking = 1;
-
-	/*
-	 * Strategy: Go to the first items of both trees. Then do
-	 *
-	 * If both trees are at level 0
-	 *   Compare keys of current items
-	 *     If left < right treat left item as new, advance left tree
-	 *       and repeat
-	 *     If left > right treat right item as deleted, advance right tree
-	 *       and repeat
-	 *     If left == right do deep compare of items, treat as changed if
-	 *       needed, advance both trees and repeat
-	 * If both trees are at the same level but not at level 0
-	 *   Compare keys of current nodes/leafs
-	 *     If left < right advance left tree and repeat
-	 *     If left > right advance right tree and repeat
-	 *     If left == right compare blockptrs of the next nodes/leafs
-	 *       If they match advance both trees but stay at the same level
-	 *         and repeat
-	 *       If they don't match advance both trees while allowing to go
-	 *         deeper and repeat
-	 * If tree levels are different
-	 *   Advance the tree that needs it and repeat
-	 *
-	 * Advancing a tree means:
-	 *   If we are at level 0, try to go to the next slot. If that's not
-	 *   possible, go one level up and repeat. Stop when we found a level
-	 *   where we could go to the next slot. We may at this point be on a
-	 *   node or a leaf.
-	 *
-	 *   If we are not at level 0 and not on shared tree blocks, go one
-	 *   level deeper.
-	 *
-	 *   If we are not at level 0 and on shared tree blocks, go one slot to
-	 *   the right if possible or go up and right.
-	 */
-
-	down_read(&fs_info->commit_root_sem);
-	left_level = btrfs_header_level(left_root->commit_root);
-	left_root_level = left_level;
-	left_path->nodes[left_level] =
-			btrfs_clone_extent_buffer(left_root->commit_root);
-	if (!left_path->nodes[left_level]) {
-		up_read(&fs_info->commit_root_sem);
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	right_level = btrfs_header_level(right_root->commit_root);
-	right_root_level = right_level;
-	right_path->nodes[right_level] =
-			btrfs_clone_extent_buffer(right_root->commit_root);
-	if (!right_path->nodes[right_level]) {
-		up_read(&fs_info->commit_root_sem);
-		ret = -ENOMEM;
-		goto out;
-	}
-	up_read(&fs_info->commit_root_sem);
-
-	if (left_level == 0)
-		btrfs_item_key_to_cpu(left_path->nodes[left_level],
-				&left_key, left_path->slots[left_level]);
-	else
-		btrfs_node_key_to_cpu(left_path->nodes[left_level],
-				&left_key, left_path->slots[left_level]);
-	if (right_level == 0)
-		btrfs_item_key_to_cpu(right_path->nodes[right_level],
-				&right_key, right_path->slots[right_level]);
-	else
-		btrfs_node_key_to_cpu(right_path->nodes[right_level],
-				&right_key, right_path->slots[right_level]);
-
-	left_end_reached = right_end_reached = 0;
-	advance_left = advance_right = 0;
-
-	while (1) {
-		if (advance_left && !left_end_reached) {
-			ret = tree_advance(left_path, &left_level,
-					left_root_level,
-					advance_left != ADVANCE_ONLY_NEXT,
-					&left_key);
-			if (ret == -1)
-				left_end_reached = ADVANCE;
-			else if (ret < 0)
-				goto out;
-			advance_left = 0;
-		}
-		if (advance_right && !right_end_reached) {
-			ret = tree_advance(right_path, &right_level,
-					right_root_level,
-					advance_right != ADVANCE_ONLY_NEXT,
-					&right_key);
-			if (ret == -1)
-				right_end_reached = ADVANCE;
-			else if (ret < 0)
-				goto out;
-			advance_right = 0;
-		}
-
-		if (left_end_reached && right_end_reached) {
-			ret = 0;
-			goto out;
-		} else if (left_end_reached) {
-			if (right_level == 0) {
-				ret = changed_cb(left_path, right_path,
-						&right_key,
-						BTRFS_COMPARE_TREE_DELETED,
-						ctx);
-				if (ret < 0)
-					goto out;
-			}
-			advance_right = ADVANCE;
-			continue;
-		} else if (right_end_reached) {
-			if (left_level == 0) {
-				ret = changed_cb(left_path, right_path,
-						&left_key,
-						BTRFS_COMPARE_TREE_NEW,
-						ctx);
-				if (ret < 0)
-					goto out;
-			}
-			advance_left = ADVANCE;
-			continue;
-		}
-
-		if (left_level == 0 && right_level == 0) {
-			cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
-			if (cmp < 0) {
-				ret = changed_cb(left_path, right_path,
-						&left_key,
-						BTRFS_COMPARE_TREE_NEW,
-						ctx);
-				if (ret < 0)
-					goto out;
-				advance_left = ADVANCE;
-			} else if (cmp > 0) {
-				ret = changed_cb(left_path, right_path,
-						&right_key,
-						BTRFS_COMPARE_TREE_DELETED,
-						ctx);
-				if (ret < 0)
-					goto out;
-				advance_right = ADVANCE;
-			} else {
-				enum btrfs_compare_tree_result result;
-
-				WARN_ON(!extent_buffer_uptodate(left_path->nodes[0]));
-				ret = tree_compare_item(left_path, right_path,
-							tmp_buf);
-				if (ret)
-					result = BTRFS_COMPARE_TREE_CHANGED;
-				else
-					result = BTRFS_COMPARE_TREE_SAME;
-				ret = changed_cb(left_path, right_path,
-						 &left_key, result, ctx);
-				if (ret < 0)
-					goto out;
-				advance_left = ADVANCE;
-				advance_right = ADVANCE;
-			}
-		} else if (left_level == right_level) {
-			cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
-			if (cmp < 0) {
-				advance_left = ADVANCE;
-			} else if (cmp > 0) {
-				advance_right = ADVANCE;
-			} else {
-				left_blockptr = btrfs_node_blockptr(
-						left_path->nodes[left_level],
-						left_path->slots[left_level]);
-				right_blockptr = btrfs_node_blockptr(
-						right_path->nodes[right_level],
-						right_path->slots[right_level]);
-				left_gen = btrfs_node_ptr_generation(
-						left_path->nodes[left_level],
-						left_path->slots[left_level]);
-				right_gen = btrfs_node_ptr_generation(
-						right_path->nodes[right_level],
-						right_path->slots[right_level]);
-				if (left_blockptr == right_blockptr &&
-				    left_gen == right_gen) {
-					/*
-					 * As we're on a shared block, don't
-					 * allow to go deeper.
-					 */
-					advance_left = ADVANCE_ONLY_NEXT;
-					advance_right = ADVANCE_ONLY_NEXT;
-				} else {
-					advance_left = ADVANCE;
-					advance_right = ADVANCE;
-				}
-			}
-		} else if (left_level < right_level) {
-			advance_right = ADVANCE;
-		} else {
-			advance_left = ADVANCE;
-		}
-	}
-
-out:
-	btrfs_free_path(left_path);
-	btrfs_free_path(right_path);
-	kvfree(tmp_buf);
-	return ret;
-}
-
 /*
  * this is similar to btrfs_next_leaf, but does not try to preserve
  * and fixup the path.  It looks for and returns the next key in the