| #include <linux/module.h> |
| #include "ctree.h" |
| #include "disk-io.h" |
| #include "transaction.h" |
| |
| static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_path *path, int level); |
| static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_key *ins_key, |
| struct btrfs_path *path, int data_size); |
| static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct buffer_head *dst, struct buffer_head |
| *src); |
| static int balance_node_right(struct btrfs_trans_handle *trans, struct |
| btrfs_root *root, struct buffer_head *dst_buf, |
| struct buffer_head *src_buf); |
| static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| struct btrfs_path *path, int level, int slot); |
| |
| inline void btrfs_init_path(struct btrfs_path *p) |
| { |
| memset(p, 0, sizeof(*p)); |
| } |
| |
| struct btrfs_path *btrfs_alloc_path(void) |
| { |
| struct btrfs_path *path; |
| path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS); |
| if (path) |
| btrfs_init_path(path); |
| return path; |
| } |
| |
| void btrfs_free_path(struct btrfs_path *p) |
| { |
| btrfs_release_path(NULL, p); |
| kmem_cache_free(btrfs_path_cachep, p); |
| } |
| |
| void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p) |
| { |
| int i; |
| for (i = 0; i < BTRFS_MAX_LEVEL; i++) { |
| if (!p->nodes[i]) |
| break; |
| btrfs_block_release(root, p->nodes[i]); |
| } |
| memset(p, 0, sizeof(*p)); |
| } |
| |
| static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct buffer_head *buf, struct buffer_head |
| *parent, int parent_slot, struct buffer_head |
| **cow_ret) |
| { |
| struct buffer_head *cow; |
| struct btrfs_node *cow_node; |
| |
| if (btrfs_header_generation(btrfs_buffer_header(buf)) == |
| trans->transid) { |
| *cow_ret = buf; |
| return 0; |
| } |
| cow = btrfs_alloc_free_block(trans, root); |
| cow_node = btrfs_buffer_node(cow); |
| if (buf->b_size != root->blocksize || cow->b_size != root->blocksize) |
| WARN_ON(1); |
| memcpy(cow_node, btrfs_buffer_node(buf), root->blocksize); |
| btrfs_set_header_blocknr(&cow_node->header, cow->b_blocknr); |
| btrfs_set_header_generation(&cow_node->header, trans->transid); |
| btrfs_inc_ref(trans, root, buf); |
| if (buf == root->node) { |
| root->node = cow; |
| get_bh(cow); |
| if (buf != root->commit_root) { |
| btrfs_free_extent(trans, root, buf->b_blocknr, 1, 1); |
| } |
| btrfs_block_release(root, buf); |
| } else { |
| btrfs_set_node_blockptr(btrfs_buffer_node(parent), parent_slot, |
| cow->b_blocknr); |
| btrfs_mark_buffer_dirty(parent); |
| btrfs_free_extent(trans, root, buf->b_blocknr, 1, 1); |
| } |
| btrfs_block_release(root, buf); |
| mark_buffer_dirty(cow); |
| *cow_ret = cow; |
| return 0; |
| } |
| |
| /* |
| * The leaf data grows from end-to-front in the node. |
| * this returns the address of the start of the last item, |
| * which is the stop of the leaf data stack |
| */ |
| static inline unsigned int leaf_data_end(struct btrfs_root *root, |
| struct btrfs_leaf *leaf) |
| { |
| u32 nr = btrfs_header_nritems(&leaf->header); |
| if (nr == 0) |
| return BTRFS_LEAF_DATA_SIZE(root); |
| return btrfs_item_offset(leaf->items + nr - 1); |
| } |
| |
| /* |
| * compare two keys in a memcmp fashion |
| */ |
| static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2) |
| { |
| struct btrfs_key k1; |
| |
| btrfs_disk_key_to_cpu(&k1, disk); |
| |
| if (k1.objectid > k2->objectid) |
| return 1; |
| if (k1.objectid < k2->objectid) |
| return -1; |
| if (k1.offset > k2->offset) |
| return 1; |
| if (k1.offset < k2->offset) |
| return -1; |
| if (k1.flags > k2->flags) |
| return 1; |
| if (k1.flags < k2->flags) |
| return -1; |
| return 0; |
| } |
| |
| static int check_node(struct btrfs_root *root, struct btrfs_path *path, |
| int level) |
| { |
| int i; |
| struct btrfs_node *parent = NULL; |
| struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]); |
| int parent_slot; |
| u32 nritems = btrfs_header_nritems(&node->header); |
| |
| if (path->nodes[level + 1]) |
| parent = btrfs_buffer_node(path->nodes[level + 1]); |
| parent_slot = path->slots[level + 1]; |
| BUG_ON(nritems == 0); |
| if (parent) { |
| struct btrfs_disk_key *parent_key; |
| parent_key = &parent->ptrs[parent_slot].key; |
| BUG_ON(memcmp(parent_key, &node->ptrs[0].key, |
| sizeof(struct btrfs_disk_key))); |
| BUG_ON(btrfs_node_blockptr(parent, parent_slot) != |
| btrfs_header_blocknr(&node->header)); |
| } |
| BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root)); |
| for (i = 0; nritems > 1 && i < nritems - 2; i++) { |
| struct btrfs_key cpukey; |
| btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[i + 1].key); |
| BUG_ON(comp_keys(&node->ptrs[i].key, &cpukey) >= 0); |
| } |
| return 0; |
| } |
| |
| static int check_leaf(struct btrfs_root *root, struct btrfs_path *path, |
| int level) |
| { |
| int i; |
| struct btrfs_leaf *leaf = btrfs_buffer_leaf(path->nodes[level]); |
| struct btrfs_node *parent = NULL; |
| int parent_slot; |
| u32 nritems = btrfs_header_nritems(&leaf->header); |
| |
| if (path->nodes[level + 1]) |
| parent = btrfs_buffer_node(path->nodes[level + 1]); |
| parent_slot = path->slots[level + 1]; |
| BUG_ON(btrfs_leaf_free_space(root, leaf) < 0); |
| |
| if (nritems == 0) |
| return 0; |
| |
| if (parent) { |
| struct btrfs_disk_key *parent_key; |
| parent_key = &parent->ptrs[parent_slot].key; |
| BUG_ON(memcmp(parent_key, &leaf->items[0].key, |
| sizeof(struct btrfs_disk_key))); |
| BUG_ON(btrfs_node_blockptr(parent, parent_slot) != |
| btrfs_header_blocknr(&leaf->header)); |
| } |
| for (i = 0; nritems > 1 && i < nritems - 2; i++) { |
| struct btrfs_key cpukey; |
| btrfs_disk_key_to_cpu(&cpukey, &leaf->items[i + 1].key); |
| BUG_ON(comp_keys(&leaf->items[i].key, |
| &cpukey) >= 0); |
| BUG_ON(btrfs_item_offset(leaf->items + i) != |
| btrfs_item_end(leaf->items + i + 1)); |
| if (i == 0) { |
| BUG_ON(btrfs_item_offset(leaf->items + i) + |
| btrfs_item_size(leaf->items + i) != |
| BTRFS_LEAF_DATA_SIZE(root)); |
| } |
| } |
| return 0; |
| } |
| |
| static int check_block(struct btrfs_root *root, struct btrfs_path *path, |
| int level) |
| { |
| if (level == 0) |
| return check_leaf(root, path, level); |
| return check_node(root, path, level); |
| } |
| |
| /* |
| * search for key in the array p. items p are item_size apart |
| * and there are 'max' items in p |
| * the slot in the array is returned via slot, and it points to |
| * the place where you would insert key if it is not found in |
| * the array. |
| * |
| * slot may point to max if the key is bigger than all of the keys |
| */ |
| static int generic_bin_search(char *p, int item_size, struct btrfs_key *key, |
| int max, int *slot) |
| { |
| int low = 0; |
| int high = max; |
| int mid; |
| int ret; |
| struct btrfs_disk_key *tmp; |
| |
| while(low < high) { |
| mid = (low + high) / 2; |
| tmp = (struct btrfs_disk_key *)(p + mid * item_size); |
| ret = comp_keys(tmp, key); |
| |
| if (ret < 0) |
| low = mid + 1; |
| else if (ret > 0) |
| high = mid; |
| else { |
| *slot = mid; |
| return 0; |
| } |
| } |
| *slot = low; |
| return 1; |
| } |
| |
| /* |
| * simple bin_search frontend that does the right thing for |
| * leaves vs nodes |
| */ |
| static int bin_search(struct btrfs_node *c, struct btrfs_key *key, int *slot) |
| { |
| if (btrfs_is_leaf(c)) { |
| struct btrfs_leaf *l = (struct btrfs_leaf *)c; |
| return generic_bin_search((void *)l->items, |
| sizeof(struct btrfs_item), |
| key, btrfs_header_nritems(&c->header), |
| slot); |
| } else { |
| return generic_bin_search((void *)c->ptrs, |
| sizeof(struct btrfs_key_ptr), |
| key, btrfs_header_nritems(&c->header), |
| slot); |
| } |
| return -1; |
| } |
| |
| static struct buffer_head *read_node_slot(struct btrfs_root *root, |
| struct buffer_head *parent_buf, |
| int slot) |
| { |
| struct btrfs_node *node = btrfs_buffer_node(parent_buf); |
| if (slot < 0) |
| return NULL; |
| if (slot >= btrfs_header_nritems(&node->header)) |
| return NULL; |
| return read_tree_block(root, btrfs_node_blockptr(node, slot)); |
| } |
| |
| static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_path *path, int level) |
| { |
| struct buffer_head *right_buf; |
| struct buffer_head *mid_buf; |
| struct buffer_head *left_buf; |
| struct buffer_head *parent_buf = NULL; |
| struct btrfs_node *right = NULL; |
| struct btrfs_node *mid; |
| struct btrfs_node *left = NULL; |
| struct btrfs_node *parent = NULL; |
| int ret = 0; |
| int wret; |
| int pslot; |
| int orig_slot = path->slots[level]; |
| u64 orig_ptr; |
| |
| if (level == 0) |
| return 0; |
| |
| mid_buf = path->nodes[level]; |
| mid = btrfs_buffer_node(mid_buf); |
| orig_ptr = btrfs_node_blockptr(mid, orig_slot); |
| |
| if (level < BTRFS_MAX_LEVEL - 1) |
| parent_buf = path->nodes[level + 1]; |
| pslot = path->slots[level + 1]; |
| |
| /* |
| * deal with the case where there is only one pointer in the root |
| * by promoting the node below to a root |
| */ |
| if (!parent_buf) { |
| struct buffer_head *child; |
| u64 blocknr = mid_buf->b_blocknr; |
| |
| if (btrfs_header_nritems(&mid->header) != 1) |
| return 0; |
| |
| /* promote the child to a root */ |
| child = read_node_slot(root, mid_buf, 0); |
| BUG_ON(!child); |
| root->node = child; |
| path->nodes[level] = NULL; |
| clean_tree_block(trans, root, mid_buf); |
| wait_on_buffer(mid_buf); |
| /* once for the path */ |
| btrfs_block_release(root, mid_buf); |
| /* once for the root ptr */ |
| btrfs_block_release(root, mid_buf); |
| return btrfs_free_extent(trans, root, blocknr, 1, 1); |
| } |
| parent = btrfs_buffer_node(parent_buf); |
| |
| if (btrfs_header_nritems(&mid->header) > |
| BTRFS_NODEPTRS_PER_BLOCK(root) / 4) |
| return 0; |
| |
| left_buf = read_node_slot(root, parent_buf, pslot - 1); |
| right_buf = read_node_slot(root, parent_buf, pslot + 1); |
| |
| /* first, try to make some room in the middle buffer */ |
| if (left_buf) { |
| btrfs_cow_block(trans, root, left_buf, parent_buf, pslot - 1, |
| &left_buf); |
| left = btrfs_buffer_node(left_buf); |
| orig_slot += btrfs_header_nritems(&left->header); |
| wret = push_node_left(trans, root, left_buf, mid_buf); |
| if (wret < 0) |
| ret = wret; |
| } |
| |
| /* |
| * then try to empty the right most buffer into the middle |
| */ |
| if (right_buf) { |
| btrfs_cow_block(trans, root, right_buf, parent_buf, pslot + 1, |
| &right_buf); |
| right = btrfs_buffer_node(right_buf); |
| wret = push_node_left(trans, root, mid_buf, right_buf); |
| if (wret < 0) |
| ret = wret; |
| if (btrfs_header_nritems(&right->header) == 0) { |
| u64 blocknr = right_buf->b_blocknr; |
| clean_tree_block(trans, root, right_buf); |
| wait_on_buffer(right_buf); |
| btrfs_block_release(root, right_buf); |
| right_buf = NULL; |
| right = NULL; |
| wret = del_ptr(trans, root, path, level + 1, pslot + |
| 1); |
| if (wret) |
| ret = wret; |
| wret = btrfs_free_extent(trans, root, blocknr, 1, 1); |
| if (wret) |
| ret = wret; |
| } else { |
| btrfs_memcpy(root, parent, |
| &parent->ptrs[pslot + 1].key, |
| &right->ptrs[0].key, |
| sizeof(struct btrfs_disk_key)); |
| btrfs_mark_buffer_dirty(parent_buf); |
| } |
| } |
| if (btrfs_header_nritems(&mid->header) == 1) { |
| /* |
| * we're not allowed to leave a node with one item in the |
| * tree during a delete. A deletion from lower in the tree |
| * could try to delete the only pointer in this node. |
| * So, pull some keys from the left. |
| * There has to be a left pointer at this point because |
| * otherwise we would have pulled some pointers from the |
| * right |
| */ |
| BUG_ON(!left_buf); |
| wret = balance_node_right(trans, root, mid_buf, left_buf); |
| if (wret < 0) |
| ret = wret; |
| BUG_ON(wret == 1); |
| } |
| if (btrfs_header_nritems(&mid->header) == 0) { |
| /* we've managed to empty the middle node, drop it */ |
| u64 blocknr = mid_buf->b_blocknr; |
| clean_tree_block(trans, root, mid_buf); |
| wait_on_buffer(mid_buf); |
| btrfs_block_release(root, mid_buf); |
| mid_buf = NULL; |
| mid = NULL; |
| wret = del_ptr(trans, root, path, level + 1, pslot); |
| if (wret) |
| ret = wret; |
| wret = btrfs_free_extent(trans, root, blocknr, 1, 1); |
| if (wret) |
| ret = wret; |
| } else { |
| /* update the parent key to reflect our changes */ |
| btrfs_memcpy(root, parent, |
| &parent->ptrs[pslot].key, &mid->ptrs[0].key, |
| sizeof(struct btrfs_disk_key)); |
| btrfs_mark_buffer_dirty(parent_buf); |
| } |
| |
| /* update the path */ |
| if (left_buf) { |
| if (btrfs_header_nritems(&left->header) > orig_slot) { |
| get_bh(left_buf); |
| path->nodes[level] = left_buf; |
| path->slots[level + 1] -= 1; |
| path->slots[level] = orig_slot; |
| if (mid_buf) |
| btrfs_block_release(root, mid_buf); |
| } else { |
| orig_slot -= btrfs_header_nritems(&left->header); |
| path->slots[level] = orig_slot; |
| } |
| } |
| /* double check we haven't messed things up */ |
| check_block(root, path, level); |
| if (orig_ptr != |
| btrfs_node_blockptr(btrfs_buffer_node(path->nodes[level]), |
| path->slots[level])) |
| BUG(); |
| |
| if (right_buf) |
| btrfs_block_release(root, right_buf); |
| if (left_buf) |
| btrfs_block_release(root, left_buf); |
| return ret; |
| } |
| |
| /* |
| * look for key in the tree. path is filled in with nodes along the way |
| * if key is found, we return zero and you can find the item in the leaf |
| * level of the path (level 0) |
| * |
| * If the key isn't found, the path points to the slot where it should |
| * be inserted, and 1 is returned. If there are other errors during the |
| * search a negative error number is returned. |
| * |
| * if ins_len > 0, nodes and leaves will be split as we walk down the |
| * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if |
| * possible) |
| */ |
| int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_key *key, struct btrfs_path *p, int |
| ins_len, int cow) |
| { |
| struct buffer_head *b; |
| struct buffer_head *cow_buf; |
| struct btrfs_node *c; |
| int slot; |
| int ret; |
| int level; |
| |
| WARN_ON(p->nodes[0] != NULL); |
| WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex)); |
| again: |
| b = root->node; |
| get_bh(b); |
| while (b) { |
| c = btrfs_buffer_node(b); |
| level = btrfs_header_level(&c->header); |
| if (cow) { |
| int wret; |
| wret = btrfs_cow_block(trans, root, b, |
| p->nodes[level + 1], |
| p->slots[level + 1], |
| &cow_buf); |
| b = cow_buf; |
| c = btrfs_buffer_node(b); |
| } |
| BUG_ON(!cow && ins_len); |
| if (level != btrfs_header_level(&c->header)) |
| WARN_ON(1); |
| level = btrfs_header_level(&c->header); |
| p->nodes[level] = b; |
| ret = check_block(root, p, level); |
| if (ret) |
| return -1; |
| ret = bin_search(c, key, &slot); |
| if (!btrfs_is_leaf(c)) { |
| if (ret && slot > 0) |
| slot -= 1; |
| p->slots[level] = slot; |
| if (ins_len > 0 && btrfs_header_nritems(&c->header) >= |
| BTRFS_NODEPTRS_PER_BLOCK(root) - 1) { |
| int sret = split_node(trans, root, p, level); |
| BUG_ON(sret > 0); |
| if (sret) |
| return sret; |
| b = p->nodes[level]; |
| c = btrfs_buffer_node(b); |
| slot = p->slots[level]; |
| } else if (ins_len < 0) { |
| int sret = balance_level(trans, root, p, |
| level); |
| if (sret) |
| return sret; |
| b = p->nodes[level]; |
| if (!b) |
| goto again; |
| c = btrfs_buffer_node(b); |
| slot = p->slots[level]; |
| BUG_ON(btrfs_header_nritems(&c->header) == 1); |
| } |
| b = read_tree_block(root, btrfs_node_blockptr(c, slot)); |
| } else { |
| struct btrfs_leaf *l = (struct btrfs_leaf *)c; |
| p->slots[level] = slot; |
| if (ins_len > 0 && btrfs_leaf_free_space(root, l) < |
| sizeof(struct btrfs_item) + ins_len) { |
| int sret = split_leaf(trans, root, key, |
| p, ins_len); |
| BUG_ON(sret > 0); |
| if (sret) |
| return sret; |
| } |
| return ret; |
| } |
| } |
| return 1; |
| } |
| |
| /* |
| * adjust the pointers going up the tree, starting at level |
| * making sure the right key of each node is points to 'key'. |
| * This is used after shifting pointers to the left, so it stops |
| * fixing up pointers when a given leaf/node is not in slot 0 of the |
| * higher levels |
| * |
| * If this fails to write a tree block, it returns -1, but continues |
| * fixing up the blocks in ram so the tree is consistent. |
| */ |
| static int fixup_low_keys(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_path *path, struct btrfs_disk_key |
| *key, int level) |
| { |
| int i; |
| int ret = 0; |
| for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
| struct btrfs_node *t; |
| int tslot = path->slots[i]; |
| if (!path->nodes[i]) |
| break; |
| t = btrfs_buffer_node(path->nodes[i]); |
| btrfs_memcpy(root, t, &t->ptrs[tslot].key, key, sizeof(*key)); |
| btrfs_mark_buffer_dirty(path->nodes[i]); |
| if (tslot != 0) |
| break; |
| } |
| return ret; |
| } |
| |
| /* |
| * try to push data from one node into the next node left in the |
| * tree. |
| * |
| * returns 0 if some ptrs were pushed left, < 0 if there was some horrible |
| * error, and > 0 if there was no room in the left hand block. |
| */ |
| static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct buffer_head *dst_buf, struct |
| buffer_head *src_buf) |
| { |
| struct btrfs_node *src = btrfs_buffer_node(src_buf); |
| struct btrfs_node *dst = btrfs_buffer_node(dst_buf); |
| int push_items = 0; |
| int src_nritems; |
| int dst_nritems; |
| int ret = 0; |
| |
| src_nritems = btrfs_header_nritems(&src->header); |
| dst_nritems = btrfs_header_nritems(&dst->header); |
| push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems; |
| if (push_items <= 0) { |
| return 1; |
| } |
| |
| if (src_nritems < push_items) |
| push_items = src_nritems; |
| |
| btrfs_memcpy(root, dst, dst->ptrs + dst_nritems, src->ptrs, |
| push_items * sizeof(struct btrfs_key_ptr)); |
| if (push_items < src_nritems) { |
| btrfs_memmove(root, src, src->ptrs, src->ptrs + push_items, |
| (src_nritems - push_items) * |
| sizeof(struct btrfs_key_ptr)); |
| } |
| btrfs_set_header_nritems(&src->header, src_nritems - push_items); |
| btrfs_set_header_nritems(&dst->header, dst_nritems + push_items); |
| btrfs_mark_buffer_dirty(src_buf); |
| btrfs_mark_buffer_dirty(dst_buf); |
| return ret; |
| } |
| |
| /* |
| * try to push data from one node into the next node right in the |
| * tree. |
| * |
| * returns 0 if some ptrs were pushed, < 0 if there was some horrible |
| * error, and > 0 if there was no room in the right hand block. |
| * |
| * this will only push up to 1/2 the contents of the left node over |
| */ |
| static int balance_node_right(struct btrfs_trans_handle *trans, struct |
| btrfs_root *root, struct buffer_head *dst_buf, |
| struct buffer_head *src_buf) |
| { |
| struct btrfs_node *src = btrfs_buffer_node(src_buf); |
| struct btrfs_node *dst = btrfs_buffer_node(dst_buf); |
| int push_items = 0; |
| int max_push; |
| int src_nritems; |
| int dst_nritems; |
| int ret = 0; |
| |
| src_nritems = btrfs_header_nritems(&src->header); |
| dst_nritems = btrfs_header_nritems(&dst->header); |
| push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems; |
| if (push_items <= 0) { |
| return 1; |
| } |
| |
| max_push = src_nritems / 2 + 1; |
| /* don't try to empty the node */ |
| if (max_push > src_nritems) |
| return 1; |
| if (max_push < push_items) |
| push_items = max_push; |
| |
| btrfs_memmove(root, dst, dst->ptrs + push_items, dst->ptrs, |
| dst_nritems * sizeof(struct btrfs_key_ptr)); |
| |
| btrfs_memcpy(root, dst, dst->ptrs, |
| src->ptrs + src_nritems - push_items, |
| push_items * sizeof(struct btrfs_key_ptr)); |
| |
| btrfs_set_header_nritems(&src->header, src_nritems - push_items); |
| btrfs_set_header_nritems(&dst->header, dst_nritems + push_items); |
| |
| btrfs_mark_buffer_dirty(src_buf); |
| btrfs_mark_buffer_dirty(dst_buf); |
| return ret; |
| } |
| |
| /* |
| * helper function to insert a new root level in the tree. |
| * A new node is allocated, and a single item is inserted to |
| * point to the existing root |
| * |
| * returns zero on success or < 0 on failure. |
| */ |
| static int insert_new_root(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_path *path, int level) |
| { |
| struct buffer_head *t; |
| struct btrfs_node *lower; |
| struct btrfs_node *c; |
| struct btrfs_disk_key *lower_key; |
| |
| BUG_ON(path->nodes[level]); |
| BUG_ON(path->nodes[level-1] != root->node); |
| |
| t = btrfs_alloc_free_block(trans, root); |
| c = btrfs_buffer_node(t); |
| memset(c, 0, root->blocksize); |
| btrfs_set_header_nritems(&c->header, 1); |
| btrfs_set_header_level(&c->header, level); |
| btrfs_set_header_blocknr(&c->header, t->b_blocknr); |
| btrfs_set_header_generation(&c->header, trans->transid); |
| btrfs_set_header_parentid(&c->header, |
| btrfs_header_parentid(btrfs_buffer_header(root->node))); |
| lower = btrfs_buffer_node(path->nodes[level-1]); |
| if (btrfs_is_leaf(lower)) |
| lower_key = &((struct btrfs_leaf *)lower)->items[0].key; |
| else |
| lower_key = &lower->ptrs[0].key; |
| btrfs_memcpy(root, c, &c->ptrs[0].key, lower_key, |
| sizeof(struct btrfs_disk_key)); |
| btrfs_set_node_blockptr(c, 0, path->nodes[level - 1]->b_blocknr); |
| |
| btrfs_mark_buffer_dirty(t); |
| |
| /* the super has an extra ref to root->node */ |
| btrfs_block_release(root, root->node); |
| root->node = t; |
| get_bh(t); |
| path->nodes[level] = t; |
| path->slots[level] = 0; |
| return 0; |
| } |
| |
| /* |
| * worker function to insert a single pointer in a node. |
| * the node should have enough room for the pointer already |
| * |
| * slot and level indicate where you want the key to go, and |
| * blocknr is the block the key points to. |
| * |
| * returns zero on success and < 0 on any error |
| */ |
| static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_path *path, struct btrfs_disk_key |
| *key, u64 blocknr, int slot, int level) |
| { |
| struct btrfs_node *lower; |
| int nritems; |
| |
| BUG_ON(!path->nodes[level]); |
| lower = btrfs_buffer_node(path->nodes[level]); |
| nritems = btrfs_header_nritems(&lower->header); |
| if (slot > nritems) |
| BUG(); |
| if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root)) |
| BUG(); |
| if (slot != nritems) { |
| btrfs_memmove(root, lower, lower->ptrs + slot + 1, |
| lower->ptrs + slot, |
| (nritems - slot) * sizeof(struct btrfs_key_ptr)); |
| } |
| btrfs_memcpy(root, lower, &lower->ptrs[slot].key, |
| key, sizeof(struct btrfs_disk_key)); |
| btrfs_set_node_blockptr(lower, slot, blocknr); |
| btrfs_set_header_nritems(&lower->header, nritems + 1); |
| btrfs_mark_buffer_dirty(path->nodes[level]); |
| return 0; |
| } |
| |
| /* |
| * split the node at the specified level in path in two. |
| * The path is corrected to point to the appropriate node after the split |
| * |
| * Before splitting this tries to make some room in the node by pushing |
| * left and right, if either one works, it returns right away. |
| * |
| * returns 0 on success and < 0 on failure |
| */ |
| static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_path *path, int level) |
| { |
| struct buffer_head *t; |
| struct btrfs_node *c; |
| struct buffer_head *split_buffer; |
| struct btrfs_node *split; |
| int mid; |
| int ret; |
| int wret; |
| u32 c_nritems; |
| |
| t = path->nodes[level]; |
| c = btrfs_buffer_node(t); |
| if (t == root->node) { |
| /* trying to split the root, lets make a new one */ |
| ret = insert_new_root(trans, root, path, level + 1); |
| if (ret) |
| return ret; |
| } |
| c_nritems = btrfs_header_nritems(&c->header); |
| split_buffer = btrfs_alloc_free_block(trans, root); |
| split = btrfs_buffer_node(split_buffer); |
| btrfs_set_header_flags(&split->header, btrfs_header_flags(&c->header)); |
| btrfs_set_header_level(&split->header, btrfs_header_level(&c->header)); |
| btrfs_set_header_blocknr(&split->header, split_buffer->b_blocknr); |
| btrfs_set_header_generation(&split->header, trans->transid); |
| btrfs_set_header_parentid(&split->header, |
| btrfs_header_parentid(btrfs_buffer_header(root->node))); |
| mid = (c_nritems + 1) / 2; |
| btrfs_memcpy(root, split, split->ptrs, c->ptrs + mid, |
| (c_nritems - mid) * sizeof(struct btrfs_key_ptr)); |
| btrfs_set_header_nritems(&split->header, c_nritems - mid); |
| btrfs_set_header_nritems(&c->header, mid); |
| ret = 0; |
| |
| btrfs_mark_buffer_dirty(t); |
| btrfs_mark_buffer_dirty(split_buffer); |
| wret = insert_ptr(trans, root, path, &split->ptrs[0].key, |
| split_buffer->b_blocknr, path->slots[level + 1] + 1, |
| level + 1); |
| if (wret) |
| ret = wret; |
| |
| if (path->slots[level] >= mid) { |
| path->slots[level] -= mid; |
| btrfs_block_release(root, t); |
| path->nodes[level] = split_buffer; |
| path->slots[level + 1] += 1; |
| } else { |
| btrfs_block_release(root, split_buffer); |
| } |
| return ret; |
| } |
| |
| /* |
| * how many bytes are required to store the items in a leaf. start |
| * and nr indicate which items in the leaf to check. This totals up the |
| * space used both by the item structs and the item data |
| */ |
| static int leaf_space_used(struct btrfs_leaf *l, int start, int nr) |
| { |
| int data_len; |
| int nritems = btrfs_header_nritems(&l->header); |
| int end = min(nritems, start + nr) - 1; |
| |
| if (!nr) |
| return 0; |
| data_len = btrfs_item_end(l->items + start); |
| data_len = data_len - btrfs_item_offset(l->items + end); |
| data_len += sizeof(struct btrfs_item) * nr; |
| WARN_ON(data_len < 0); |
| return data_len; |
| } |
| |
| /* |
| * The space between the end of the leaf items and |
| * the start of the leaf data. IOW, how much room |
| * the leaf has left for both items and data |
| */ |
| int btrfs_leaf_free_space(struct btrfs_root *root, struct btrfs_leaf *leaf) |
| { |
| int nritems = btrfs_header_nritems(&leaf->header); |
| return BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems); |
| } |
| |
| /* |
| * push some data in the path leaf to the right, trying to free up at |
| * least data_size bytes. returns zero if the push worked, nonzero otherwise |
| * |
| * returns 1 if the push failed because the other node didn't have enough |
| * room, 0 if everything worked out and < 0 if there were major errors. |
| */ |
| static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_path *path, int data_size) |
| { |
| struct buffer_head *left_buf = path->nodes[0]; |
| struct btrfs_leaf *left = btrfs_buffer_leaf(left_buf); |
| struct btrfs_leaf *right; |
| struct buffer_head *right_buf; |
| struct buffer_head *upper; |
| struct btrfs_node *upper_node; |
| int slot; |
| int i; |
| int free_space; |
| int push_space = 0; |
| int push_items = 0; |
| struct btrfs_item *item; |
| u32 left_nritems; |
| u32 right_nritems; |
| |
| slot = path->slots[1]; |
| if (!path->nodes[1]) { |
| return 1; |
| } |
| upper = path->nodes[1]; |
| upper_node = btrfs_buffer_node(upper); |
| if (slot >= btrfs_header_nritems(&upper_node->header) - 1) { |
| return 1; |
| } |
| right_buf = read_tree_block(root, |
| btrfs_node_blockptr(btrfs_buffer_node(upper), slot + 1)); |
| right = btrfs_buffer_leaf(right_buf); |
| free_space = btrfs_leaf_free_space(root, right); |
| if (free_space < data_size + sizeof(struct btrfs_item)) { |
| btrfs_block_release(root, right_buf); |
| return 1; |
| } |
| /* cow and double check */ |
| btrfs_cow_block(trans, root, right_buf, upper, slot + 1, &right_buf); |
| right = btrfs_buffer_leaf(right_buf); |
| free_space = btrfs_leaf_free_space(root, right); |
| if (free_space < data_size + sizeof(struct btrfs_item)) { |
| btrfs_block_release(root, right_buf); |
| return 1; |
| } |
| |
| left_nritems = btrfs_header_nritems(&left->header); |
| for (i = left_nritems - 1; i >= 0; i--) { |
| item = left->items + i; |
| if (path->slots[0] == i) |
| push_space += data_size + sizeof(*item); |
| if (btrfs_item_size(item) + sizeof(*item) + push_space > |
| free_space) |
| break; |
| push_items++; |
| push_space += btrfs_item_size(item) + sizeof(*item); |
| } |
| if (push_items == 0) { |
| btrfs_block_release(root, right_buf); |
| return 1; |
| } |
| right_nritems = btrfs_header_nritems(&right->header); |
| /* push left to right */ |
| push_space = btrfs_item_end(left->items + left_nritems - push_items); |
| push_space -= leaf_data_end(root, left); |
| /* make room in the right data area */ |
| btrfs_memmove(root, right, btrfs_leaf_data(right) + |
| leaf_data_end(root, right) - push_space, |
| btrfs_leaf_data(right) + |
| leaf_data_end(root, right), BTRFS_LEAF_DATA_SIZE(root) - |
| leaf_data_end(root, right)); |
| /* copy from the left data area */ |
| btrfs_memcpy(root, right, btrfs_leaf_data(right) + |
| BTRFS_LEAF_DATA_SIZE(root) - push_space, |
| btrfs_leaf_data(left) + leaf_data_end(root, left), |
| push_space); |
| btrfs_memmove(root, right, right->items + push_items, right->items, |
| right_nritems * sizeof(struct btrfs_item)); |
| /* copy the items from left to right */ |
| btrfs_memcpy(root, right, right->items, left->items + |
| left_nritems - push_items, |
| push_items * sizeof(struct btrfs_item)); |
| |
| /* update the item pointers */ |
| right_nritems += push_items; |
| btrfs_set_header_nritems(&right->header, right_nritems); |
| push_space = BTRFS_LEAF_DATA_SIZE(root); |
| for (i = 0; i < right_nritems; i++) { |
| btrfs_set_item_offset(right->items + i, push_space - |
| btrfs_item_size(right->items + i)); |
| push_space = btrfs_item_offset(right->items + i); |
| } |
| left_nritems -= push_items; |
| btrfs_set_header_nritems(&left->header, left_nritems); |
| |
| btrfs_mark_buffer_dirty(left_buf); |
| btrfs_mark_buffer_dirty(right_buf); |
| btrfs_memcpy(root, upper_node, &upper_node->ptrs[slot + 1].key, |
| &right->items[0].key, sizeof(struct btrfs_disk_key)); |
| btrfs_mark_buffer_dirty(upper); |
| |
| /* then fixup the leaf pointer in the path */ |
| if (path->slots[0] >= left_nritems) { |
| path->slots[0] -= left_nritems; |
| btrfs_block_release(root, path->nodes[0]); |
| path->nodes[0] = right_buf; |
| path->slots[1] += 1; |
| } else { |
| btrfs_block_release(root, right_buf); |
| } |
| return 0; |
| } |
| /* |
| * push some data in the path leaf to the left, trying to free up at |
| * least data_size bytes. returns zero if the push worked, nonzero otherwise |
| */ |
| static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_path *path, int data_size) |
| { |
| struct buffer_head *right_buf = path->nodes[0]; |
| struct btrfs_leaf *right = btrfs_buffer_leaf(right_buf); |
| struct buffer_head *t; |
| struct btrfs_leaf *left; |
| int slot; |
| int i; |
| int free_space; |
| int push_space = 0; |
| int push_items = 0; |
| struct btrfs_item *item; |
| u32 old_left_nritems; |
| int ret = 0; |
| int wret; |
| |
| slot = path->slots[1]; |
| if (slot == 0) { |
| return 1; |
| } |
| if (!path->nodes[1]) { |
| return 1; |
| } |
| t = read_tree_block(root, |
| btrfs_node_blockptr(btrfs_buffer_node(path->nodes[1]), slot - 1)); |
| left = btrfs_buffer_leaf(t); |
| free_space = btrfs_leaf_free_space(root, left); |
| if (free_space < data_size + sizeof(struct btrfs_item)) { |
| btrfs_block_release(root, t); |
| return 1; |
| } |
| |
| /* cow and double check */ |
| btrfs_cow_block(trans, root, t, path->nodes[1], slot - 1, &t); |
| left = btrfs_buffer_leaf(t); |
| free_space = btrfs_leaf_free_space(root, left); |
| if (free_space < data_size + sizeof(struct btrfs_item)) { |
| btrfs_block_release(root, t); |
| return 1; |
| } |
| |
| for (i = 0; i < btrfs_header_nritems(&right->header); i++) { |
| item = right->items + i; |
| if (path->slots[0] == i) |
| push_space += data_size + sizeof(*item); |
| if (btrfs_item_size(item) + sizeof(*item) + push_space > |
| free_space) |
| break; |
| push_items++; |
| push_space += btrfs_item_size(item) + sizeof(*item); |
| } |
| if (push_items == 0) { |
| btrfs_block_release(root, t); |
| return 1; |
| } |
| /* push data from right to left */ |
| btrfs_memcpy(root, left, left->items + |
| btrfs_header_nritems(&left->header), |
| right->items, push_items * sizeof(struct btrfs_item)); |
| push_space = BTRFS_LEAF_DATA_SIZE(root) - |
| btrfs_item_offset(right->items + push_items -1); |
| btrfs_memcpy(root, left, btrfs_leaf_data(left) + |
| leaf_data_end(root, left) - push_space, |
| btrfs_leaf_data(right) + |
| btrfs_item_offset(right->items + push_items - 1), |
| push_space); |
| old_left_nritems = btrfs_header_nritems(&left->header); |
| BUG_ON(old_left_nritems < 0); |
| |
| for (i = old_left_nritems; i < old_left_nritems + push_items; i++) { |
| u32 ioff = btrfs_item_offset(left->items + i); |
| btrfs_set_item_offset(left->items + i, ioff - |
| (BTRFS_LEAF_DATA_SIZE(root) - |
| btrfs_item_offset(left->items + |
| old_left_nritems - 1))); |
| } |
| btrfs_set_header_nritems(&left->header, old_left_nritems + push_items); |
| |
| /* fixup right node */ |
| push_space = btrfs_item_offset(right->items + push_items - 1) - |
| leaf_data_end(root, right); |
| btrfs_memmove(root, right, btrfs_leaf_data(right) + |
| BTRFS_LEAF_DATA_SIZE(root) - push_space, |
| btrfs_leaf_data(right) + |
| leaf_data_end(root, right), push_space); |
| btrfs_memmove(root, right, right->items, right->items + push_items, |
| (btrfs_header_nritems(&right->header) - push_items) * |
| sizeof(struct btrfs_item)); |
| btrfs_set_header_nritems(&right->header, |
| btrfs_header_nritems(&right->header) - |
| push_items); |
| push_space = BTRFS_LEAF_DATA_SIZE(root); |
| |
| for (i = 0; i < btrfs_header_nritems(&right->header); i++) { |
| btrfs_set_item_offset(right->items + i, push_space - |
| btrfs_item_size(right->items + i)); |
| push_space = btrfs_item_offset(right->items + i); |
| } |
| |
| btrfs_mark_buffer_dirty(t); |
| btrfs_mark_buffer_dirty(right_buf); |
| |
| wret = fixup_low_keys(trans, root, path, &right->items[0].key, 1); |
| if (wret) |
| ret = wret; |
| |
| /* then fixup the leaf pointer in the path */ |
| if (path->slots[0] < push_items) { |
| path->slots[0] += old_left_nritems; |
| btrfs_block_release(root, path->nodes[0]); |
| path->nodes[0] = t; |
| path->slots[1] -= 1; |
| } else { |
| btrfs_block_release(root, t); |
| path->slots[0] -= push_items; |
| } |
| BUG_ON(path->slots[0] < 0); |
| return ret; |
| } |
| |
| /* |
| * split the path's leaf in two, making sure there is at least data_size |
| * available for the resulting leaf level of the path. |
| * |
| * returns 0 if all went well and < 0 on failure. |
| */ |
| static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_key *ins_key, |
| struct btrfs_path *path, int data_size) |
| { |
| struct buffer_head *l_buf; |
| struct btrfs_leaf *l; |
| u32 nritems; |
| int mid; |
| int slot; |
| struct btrfs_leaf *right; |
| struct buffer_head *right_buffer; |
| int space_needed = data_size + sizeof(struct btrfs_item); |
| int data_copy_size; |
| int rt_data_off; |
| int i; |
| int ret = 0; |
| int wret; |
| int double_split = 0; |
| struct btrfs_disk_key disk_key; |
| |
| /* first try to make some room by pushing left and right */ |
| wret = push_leaf_left(trans, root, path, data_size); |
| if (wret < 0) |
| return wret; |
| if (wret) { |
| wret = push_leaf_right(trans, root, path, data_size); |
| if (wret < 0) |
| return wret; |
| } |
| l_buf = path->nodes[0]; |
| l = btrfs_buffer_leaf(l_buf); |
| |
| /* did the pushes work? */ |
| if (btrfs_leaf_free_space(root, l) >= |
| sizeof(struct btrfs_item) + data_size) |
| return 0; |
| |
| if (!path->nodes[1]) { |
| ret = insert_new_root(trans, root, path, 1); |
| if (ret) |
| return ret; |
| } |
| slot = path->slots[0]; |
| nritems = btrfs_header_nritems(&l->header); |
| mid = (nritems + 1)/ 2; |
| right_buffer = btrfs_alloc_free_block(trans, root); |
| BUG_ON(!right_buffer); |
| right = btrfs_buffer_leaf(right_buffer); |
| memset(&right->header, 0, sizeof(right->header)); |
| btrfs_set_header_blocknr(&right->header, right_buffer->b_blocknr); |
| btrfs_set_header_generation(&right->header, trans->transid); |
| btrfs_set_header_level(&right->header, 0); |
| btrfs_set_header_parentid(&right->header, |
| btrfs_header_parentid(btrfs_buffer_header(root->node))); |
| if (mid <= slot) { |
| if (nritems == 1 || |
| leaf_space_used(l, mid, nritems - mid) + space_needed > |
| BTRFS_LEAF_DATA_SIZE(root)) { |
| if (slot >= nritems) { |
| btrfs_cpu_key_to_disk(&disk_key, ins_key); |
| btrfs_set_header_nritems(&right->header, 0); |
| wret = insert_ptr(trans, root, path, |
| &disk_key, |
| right_buffer->b_blocknr, |
| path->slots[1] + 1, 1); |
| if (wret) |
| ret = wret; |
| btrfs_block_release(root, path->nodes[0]); |
| path->nodes[0] = right_buffer; |
| path->slots[0] = 0; |
| path->slots[1] += 1; |
| return ret; |
| } |
| mid = slot; |
| double_split = 1; |
| } |
| } else { |
| if (leaf_space_used(l, 0, mid + 1) + space_needed > |
| BTRFS_LEAF_DATA_SIZE(root)) { |
| if (slot == 0) { |
| btrfs_cpu_key_to_disk(&disk_key, ins_key); |
| btrfs_set_header_nritems(&right->header, 0); |
| wret = insert_ptr(trans, root, path, |
| &disk_key, |
| right_buffer->b_blocknr, |
| path->slots[1] - 1, 1); |
| if (wret) |
| ret = wret; |
| btrfs_block_release(root, path->nodes[0]); |
| path->nodes[0] = right_buffer; |
| path->slots[0] = 0; |
| path->slots[1] -= 1; |
| return ret; |
| } |
| mid = slot; |
| double_split = 1; |
| } |
| } |
| btrfs_set_header_nritems(&right->header, nritems - mid); |
| data_copy_size = btrfs_item_end(l->items + mid) - |
| leaf_data_end(root, l); |
| btrfs_memcpy(root, right, right->items, l->items + mid, |
| (nritems - mid) * sizeof(struct btrfs_item)); |
| btrfs_memcpy(root, right, |
| btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) - |
| data_copy_size, btrfs_leaf_data(l) + |
| leaf_data_end(root, l), data_copy_size); |
| rt_data_off = BTRFS_LEAF_DATA_SIZE(root) - |
| btrfs_item_end(l->items + mid); |
| |
| for (i = 0; i < btrfs_header_nritems(&right->header); i++) { |
| u32 ioff = btrfs_item_offset(right->items + i); |
| btrfs_set_item_offset(right->items + i, ioff + rt_data_off); |
| } |
| |
| btrfs_set_header_nritems(&l->header, mid); |
| ret = 0; |
| wret = insert_ptr(trans, root, path, &right->items[0].key, |
| right_buffer->b_blocknr, path->slots[1] + 1, 1); |
| if (wret) |
| ret = wret; |
| btrfs_mark_buffer_dirty(right_buffer); |
| btrfs_mark_buffer_dirty(l_buf); |
| BUG_ON(path->slots[0] != slot); |
| if (mid <= slot) { |
| btrfs_block_release(root, path->nodes[0]); |
| path->nodes[0] = right_buffer; |
| path->slots[0] -= mid; |
| path->slots[1] += 1; |
| } else |
| btrfs_block_release(root, right_buffer); |
| BUG_ON(path->slots[0] < 0); |
| |
| if (!double_split) |
| return ret; |
| right_buffer = btrfs_alloc_free_block(trans, root); |
| BUG_ON(!right_buffer); |
| right = btrfs_buffer_leaf(right_buffer); |
| memset(&right->header, 0, sizeof(right->header)); |
| btrfs_set_header_blocknr(&right->header, right_buffer->b_blocknr); |
| btrfs_set_header_generation(&right->header, trans->transid); |
| btrfs_set_header_level(&right->header, 0); |
| btrfs_set_header_parentid(&right->header, |
| btrfs_header_parentid(btrfs_buffer_header(root->node))); |
| btrfs_cpu_key_to_disk(&disk_key, ins_key); |
| btrfs_set_header_nritems(&right->header, 0); |
| wret = insert_ptr(trans, root, path, |
| &disk_key, |
| right_buffer->b_blocknr, |
| path->slots[1], 1); |
| if (wret) |
| ret = wret; |
| btrfs_block_release(root, path->nodes[0]); |
| path->nodes[0] = right_buffer; |
| path->slots[0] = 0; |
| check_node(root, path, 1); |
| check_leaf(root, path, 0); |
| return ret; |
| } |
| |
| /* |
| * Given a key and some data, insert an item into the tree. |
| * This does all the path init required, making room in the tree if needed. |
| */ |
| int btrfs_insert_empty_item(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_path *path, struct btrfs_key |
| *cpu_key, u32 data_size) |
| { |
| int ret = 0; |
| int slot; |
| int slot_orig; |
| struct btrfs_leaf *leaf; |
| struct buffer_head *leaf_buf; |
| u32 nritems; |
| unsigned int data_end; |
| struct btrfs_disk_key disk_key; |
| |
| btrfs_cpu_key_to_disk(&disk_key, cpu_key); |
| |
| /* create a root if there isn't one */ |
| if (!root->node) |
| BUG(); |
| ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1); |
| if (ret == 0) { |
| return -EEXIST; |
| } |
| if (ret < 0) |
| goto out; |
| |
| slot_orig = path->slots[0]; |
| leaf_buf = path->nodes[0]; |
| leaf = btrfs_buffer_leaf(leaf_buf); |
| |
| nritems = btrfs_header_nritems(&leaf->header); |
| data_end = leaf_data_end(root, leaf); |
| |
| if (btrfs_leaf_free_space(root, leaf) < |
| sizeof(struct btrfs_item) + data_size) { |
| BUG(); |
| } |
| slot = path->slots[0]; |
| BUG_ON(slot < 0); |
| if (slot != nritems) { |
| int i; |
| unsigned int old_data = btrfs_item_end(leaf->items + slot); |
| |
| /* |
| * item0..itemN ... dataN.offset..dataN.size .. data0.size |
| */ |
| /* first correct the data pointers */ |
| for (i = slot; i < nritems; i++) { |
| u32 ioff = btrfs_item_offset(leaf->items + i); |
| btrfs_set_item_offset(leaf->items + i, |
| ioff - data_size); |
| } |
| |
| /* shift the items */ |
| btrfs_memmove(root, leaf, leaf->items + slot + 1, |
| leaf->items + slot, |
| (nritems - slot) * sizeof(struct btrfs_item)); |
| |
| /* shift the data */ |
| btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) + |
| data_end - data_size, btrfs_leaf_data(leaf) + |
| data_end, old_data - data_end); |
| data_end = old_data; |
| } |
| /* setup the item for the new data */ |
| btrfs_memcpy(root, leaf, &leaf->items[slot].key, &disk_key, |
| sizeof(struct btrfs_disk_key)); |
| btrfs_set_item_offset(leaf->items + slot, data_end - data_size); |
| btrfs_set_item_size(leaf->items + slot, data_size); |
| btrfs_set_header_nritems(&leaf->header, nritems + 1); |
| btrfs_mark_buffer_dirty(leaf_buf); |
| |
| ret = 0; |
| if (slot == 0) |
| ret = fixup_low_keys(trans, root, path, &disk_key, 1); |
| |
| if (btrfs_leaf_free_space(root, leaf) < 0) |
| BUG(); |
| check_leaf(root, path, 0); |
| out: |
| return ret; |
| } |
| |
| /* |
| * Given a key and some data, insert an item into the tree. |
| * This does all the path init required, making room in the tree if needed. |
| */ |
| int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_key *cpu_key, void *data, u32 |
| data_size) |
| { |
| int ret = 0; |
| struct btrfs_path *path; |
| u8 *ptr; |
| |
| path = btrfs_alloc_path(); |
| BUG_ON(!path); |
| btrfs_init_path(path); |
| ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size); |
| if (!ret) { |
| ptr = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), |
| path->slots[0], u8); |
| btrfs_memcpy(root, path->nodes[0]->b_data, |
| ptr, data, data_size); |
| btrfs_mark_buffer_dirty(path->nodes[0]); |
| } |
| btrfs_release_path(root, path); |
| btrfs_free_path(path); |
| return ret; |
| } |
| |
| /* |
| * delete the pointer from a given node. |
| * |
| * If the delete empties a node, the node is removed from the tree, |
| * continuing all the way the root if required. The root is converted into |
| * a leaf if all the nodes are emptied. |
| */ |
| static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| struct btrfs_path *path, int level, int slot) |
| { |
| struct btrfs_node *node; |
| struct buffer_head *parent = path->nodes[level]; |
| u32 nritems; |
| int ret = 0; |
| int wret; |
| |
| node = btrfs_buffer_node(parent); |
| nritems = btrfs_header_nritems(&node->header); |
| if (slot != nritems -1) { |
| btrfs_memmove(root, node, node->ptrs + slot, |
| node->ptrs + slot + 1, |
| sizeof(struct btrfs_key_ptr) * |
| (nritems - slot - 1)); |
| } |
| nritems--; |
| btrfs_set_header_nritems(&node->header, nritems); |
| if (nritems == 0 && parent == root->node) { |
| struct btrfs_header *header = btrfs_buffer_header(root->node); |
| BUG_ON(btrfs_header_level(header) != 1); |
| /* just turn the root into a leaf and break */ |
| btrfs_set_header_level(header, 0); |
| } else if (slot == 0) { |
| wret = fixup_low_keys(trans, root, path, &node->ptrs[0].key, |
| level + 1); |
| if (wret) |
| ret = wret; |
| } |
| btrfs_mark_buffer_dirty(parent); |
| return ret; |
| } |
| |
| /* |
| * delete the item at the leaf level in path. If that empties |
| * the leaf, remove it from the tree |
| */ |
| int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| struct btrfs_path *path) |
| { |
| int slot; |
| struct btrfs_leaf *leaf; |
| struct buffer_head *leaf_buf; |
| int doff; |
| int dsize; |
| int ret = 0; |
| int wret; |
| u32 nritems; |
| |
| leaf_buf = path->nodes[0]; |
| leaf = btrfs_buffer_leaf(leaf_buf); |
| slot = path->slots[0]; |
| doff = btrfs_item_offset(leaf->items + slot); |
| dsize = btrfs_item_size(leaf->items + slot); |
| nritems = btrfs_header_nritems(&leaf->header); |
| |
| if (slot != nritems - 1) { |
| int i; |
| int data_end = leaf_data_end(root, leaf); |
| btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) + |
| data_end + dsize, |
| btrfs_leaf_data(leaf) + data_end, |
| doff - data_end); |
| for (i = slot + 1; i < nritems; i++) { |
| u32 ioff = btrfs_item_offset(leaf->items + i); |
| btrfs_set_item_offset(leaf->items + i, ioff + dsize); |
| } |
| btrfs_memmove(root, leaf, leaf->items + slot, |
| leaf->items + slot + 1, |
| sizeof(struct btrfs_item) * |
| (nritems - slot - 1)); |
| } |
| btrfs_set_header_nritems(&leaf->header, nritems - 1); |
| nritems--; |
| /* delete the leaf if we've emptied it */ |
| if (nritems == 0) { |
| if (leaf_buf == root->node) { |
| btrfs_set_header_level(&leaf->header, 0); |
| } else { |
| clean_tree_block(trans, root, leaf_buf); |
| wait_on_buffer(leaf_buf); |
| wret = del_ptr(trans, root, path, 1, path->slots[1]); |
| if (wret) |
| ret = wret; |
| wret = btrfs_free_extent(trans, root, |
| leaf_buf->b_blocknr, 1, 1); |
| if (wret) |
| ret = wret; |
| } |
| } else { |
| int used = leaf_space_used(leaf, 0, nritems); |
| if (slot == 0) { |
| wret = fixup_low_keys(trans, root, path, |
| &leaf->items[0].key, 1); |
| if (wret) |
| ret = wret; |
| } |
| |
| /* delete the leaf if it is mostly empty */ |
| if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) { |
| /* push_leaf_left fixes the path. |
| * make sure the path still points to our leaf |
| * for possible call to del_ptr below |
| */ |
| slot = path->slots[1]; |
| get_bh(leaf_buf); |
| wret = push_leaf_left(trans, root, path, 1); |
| if (wret < 0) |
| ret = wret; |
| if (path->nodes[0] == leaf_buf && |
| btrfs_header_nritems(&leaf->header)) { |
| wret = push_leaf_right(trans, root, path, 1); |
| if (wret < 0) |
| ret = wret; |
| } |
| if (btrfs_header_nritems(&leaf->header) == 0) { |
| u64 blocknr = leaf_buf->b_blocknr; |
| clean_tree_block(trans, root, leaf_buf); |
| wait_on_buffer(leaf_buf); |
| wret = del_ptr(trans, root, path, 1, slot); |
| if (wret) |
| ret = wret; |
| btrfs_block_release(root, leaf_buf); |
| wret = btrfs_free_extent(trans, root, blocknr, |
| 1, 1); |
| if (wret) |
| ret = wret; |
| } else { |
| btrfs_mark_buffer_dirty(leaf_buf); |
| btrfs_block_release(root, leaf_buf); |
| } |
| } else { |
| btrfs_mark_buffer_dirty(leaf_buf); |
| } |
| } |
| return ret; |
| } |
| |
| /* |
| * walk up the tree as far as required to find the next leaf. |
| * returns 0 if it found something or 1 if there are no greater leaves. |
| * returns < 0 on io errors. |
| */ |
| int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) |
| { |
| int slot; |
| int level = 1; |
| u64 blocknr; |
| struct buffer_head *c; |
| struct btrfs_node *c_node; |
| struct buffer_head *next = NULL; |
| |
| while(level < BTRFS_MAX_LEVEL) { |
| if (!path->nodes[level]) |
| return 1; |
| slot = path->slots[level] + 1; |
| c = path->nodes[level]; |
| c_node = btrfs_buffer_node(c); |
| if (slot >= btrfs_header_nritems(&c_node->header)) { |
| level++; |
| continue; |
| } |
| blocknr = btrfs_node_blockptr(c_node, slot); |
| if (next) |
| btrfs_block_release(root, next); |
| next = read_tree_block(root, blocknr); |
| break; |
| } |
| path->slots[level] = slot; |
| while(1) { |
| level--; |
| c = path->nodes[level]; |
| btrfs_block_release(root, c); |
| path->nodes[level] = next; |
| path->slots[level] = 0; |
| if (!level) |
| break; |
| next = read_tree_block(root, |
| btrfs_node_blockptr(btrfs_buffer_node(next), 0)); |
| } |
| return 0; |
| } |