diff options
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/ctree.c | 362 | ||||
| -rw-r--r-- | fs/btrfs/ctree.h | 14 | ||||
| -rw-r--r-- | fs/btrfs/send.c | 374 |
3 files changed, 374 insertions, 376 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 diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index dc465df47b32..17cd88521ad2 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2590,20 +2590,6 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key, struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent, int slot); -enum btrfs_compare_tree_result { - BTRFS_COMPARE_TREE_NEW, - BTRFS_COMPARE_TREE_DELETED, - BTRFS_COMPARE_TREE_CHANGED, - BTRFS_COMPARE_TREE_SAME, -}; -typedef int (*btrfs_changed_cb_t)(struct btrfs_path *left_path, - struct btrfs_path *right_path, - struct btrfs_key *key, - enum btrfs_compare_tree_result result, - void *ctx); -int btrfs_compare_trees(struct btrfs_root *left_root, - struct btrfs_root *right_root, - btrfs_changed_cb_t cb, void *ctx); int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf, struct extent_buffer *parent, int parent_slot, diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index c3c0c064c25d..f856d6ca3771 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -260,6 +260,21 @@ struct name_cache_entry { char name[]; }; +#define ADVANCE 1 +#define ADVANCE_ONLY_NEXT -1 + +enum btrfs_compare_tree_result { + BTRFS_COMPARE_TREE_NEW, + BTRFS_COMPARE_TREE_DELETED, + BTRFS_COMPARE_TREE_CHANGED, + BTRFS_COMPARE_TREE_SAME, +}; +typedef int (*btrfs_changed_cb_t)(struct btrfs_path *left_path, + struct btrfs_path *right_path, + struct btrfs_key *key, + enum btrfs_compare_tree_result result, + void *ctx); + __cold static void inconsistent_snapshot_error(struct send_ctx *sctx, enum btrfs_compare_tree_result result, @@ -6514,6 +6529,365 @@ 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; +} + +/* + * 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. + */ +static 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; +} + static int send_subvol(struct send_ctx *sctx) { int ret; |