#include #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, buf->b_blocknr); 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, bh_blocknr(cow)); btrfs_set_header_generation(&cow_node->header, trans->transid); btrfs_set_header_owner(&cow_node->header, root->root_key.objectid); 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, bh_blocknr(buf), 1, 1); } btrfs_block_release(root, buf); } else { btrfs_set_node_blockptr(btrfs_buffer_node(parent), parent_slot, bh_blocknr(cow)); btrfs_mark_buffer_dirty(parent); btrfs_free_extent(trans, root, bh_blocknr(buf), 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.flags > k2->flags) return 1; if (k1.flags < k2->flags) return -1; if (k1.offset > k2->offset) return 1; if (k1.offset < k2->offset) return -1; return 0; } static int check_node(struct btrfs_root *root, struct btrfs_path *path, int level) { struct btrfs_node *parent = NULL; struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]); int parent_slot; int slot; struct btrfs_key cpukey; 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]; slot = path->slots[level]; 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)); if (slot != 0) { btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[slot - 1].key); BUG_ON(comp_keys(&node->ptrs[slot].key, &cpukey) <= 0); } if (slot < nritems - 1) { btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[slot + 1].key); BUG_ON(comp_keys(&node->ptrs[slot].key, &cpukey) >= 0); } return 0; } static int check_leaf(struct btrfs_root *root, struct btrfs_path *path, int level) { struct btrfs_leaf *leaf = btrfs_buffer_leaf(path->nodes[level]); struct btrfs_node *parent = NULL; int parent_slot; int slot = path->slots[0]; struct btrfs_key cpukey; 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)); } if (slot != 0) { btrfs_disk_key_to_cpu(&cpukey, &leaf->items[slot - 1].key); BUG_ON(comp_keys(&leaf->items[slot].key, &cpukey) <= 0); BUG_ON(btrfs_item_offset(leaf->items + slot - 1) != btrfs_item_end(leaf->items + slot)); } if (slot < nritems - 1) { btrfs_disk_key_to_cpu(&cpukey, &leaf->items[slot + 1].key); BUG_ON(comp_keys(&leaf->items[slot].key, &cpukey) >= 0); BUG_ON(btrfs_item_offset(leaf->items + slot) != btrfs_item_end(leaf->items + slot + 1)); } BUG_ON(btrfs_item_offset(leaf->items) + btrfs_item_size(leaf->items) != BTRFS_LEAF_DATA_SIZE(root)); return 0; } static int check_block(struct btrfs_root *root, struct btrfs_path *path, int level) { struct btrfs_node *node = btrfs_buffer_node(path->nodes[level]); if (memcmp(node->header.fsid, root->fs_info->disk_super->fsid, sizeof(node->header.fsid))) BUG(); 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 = bh_blocknr(mid_buf); 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 = bh_blocknr(right_buf); 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 = bh_blocknr(mid_buf); 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; } /* returns zero if the push worked, non-zero otherwise */ static int push_nodes_for_insert(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 1; 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]; if (!parent_buf) return 1; parent = btrfs_buffer_node(parent_buf); left_buf = read_node_slot(root, parent_buf, pslot - 1); /* first, try to make some room in the middle buffer */ if (left_buf) { u32 left_nr; left = btrfs_buffer_node(left_buf); left_nr = btrfs_header_nritems(&left->header); if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) { wret = 1; } else { btrfs_cow_block(trans, root, left_buf, parent_buf, pslot - 1, &left_buf); left = btrfs_buffer_node(left_buf); wret = push_node_left(trans, root, left_buf, mid_buf); } if (wret < 0) ret = wret; if (wret == 0) { orig_slot += left_nr; btrfs_memcpy(root, parent, &parent->ptrs[pslot].key, &mid->ptrs[0].key, sizeof(struct btrfs_disk_key)); btrfs_mark_buffer_dirty(parent_buf); if (btrfs_header_nritems(&left->header) > orig_slot) { path->nodes[level] = left_buf; path->slots[level + 1] -= 1; path->slots[level] = orig_slot; btrfs_block_release(root, mid_buf); } else { orig_slot -= btrfs_header_nritems(&left->header); path->slots[level] = orig_slot; btrfs_block_release(root, left_buf); } check_node(root, path, level); return 0; } btrfs_block_release(root, left_buf); } right_buf = read_node_slot(root, parent_buf, pslot + 1); /* * then try to empty the right most buffer into the middle */ if (right_buf) { u32 right_nr; right = btrfs_buffer_node(right_buf); right_nr = btrfs_header_nritems(&right->header); if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) { wret = 1; } else { btrfs_cow_block(trans, root, right_buf, parent_buf, pslot + 1, &right_buf); right = btrfs_buffer_node(right_buf); wret = balance_node_right(trans, root, right_buf, mid_buf); } if (wret < 0) ret = wret; if (wret == 0) { 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) <= orig_slot) { path->nodes[level] = right_buf; path->slots[level + 1] += 1; path->slots[level] = orig_slot - btrfs_header_nritems(&mid->header); btrfs_block_release(root, mid_buf); } else { btrfs_block_release(root, right_buf); } check_node(root, path, level); return 0; } btrfs_block_release(root, right_buf); } check_node(root, path, level); return 1; } /* * 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, root->node->b_blocknr); 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, bh_blocknr(t)); btrfs_set_header_generation(&c->header, trans->transid); btrfs_set_header_owner(&c->header, root->root_key.objectid); lower = btrfs_buffer_node(path->nodes[level-1]); memcpy(c->header.fsid, root->fs_info->disk_super->fsid, sizeof(c->header.fsid)); 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, bh_blocknr(path->nodes[level - 1])); 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; } else { ret = push_nodes_for_insert(trans, root, path, level); t = path->nodes[level]; c = btrfs_buffer_node(t); if (!ret && btrfs_header_nritems(&c->header) < BTRFS_NODEPTRS_PER_BLOCK(root) - 1) return 0; } c_nritems = btrfs_header_nritems(&c->header); split_buffer = btrfs_alloc_free_block(trans, root, t->b_blocknr); 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, bh_blocknr(split_buffer)); btrfs_set_header_generation(&split->header, trans->transid); btrfs_set_header_owner(&split->header, root->root_key.objectid); memcpy(split->header.fsid, root->fs_info->disk_super->fsid, sizeof(split->header.fsid)); 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, bh_blocknr(split_buffer), 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); if (left_nritems == 0) { btrfs_block_release(root, right_buf); return 1; } for (i = left_nritems - 1; i >= 1; 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; } if (push_items == left_nritems) WARN_ON(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; } if (btrfs_header_nritems(&right->header) == 0) { btrfs_block_release(root, t); return 1; } for (i = 0; i < btrfs_header_nritems(&right->header) - 1; 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; } if (push_items == btrfs_header_nritems(&right->header)) WARN_ON(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, l_buf->b_blocknr); BUG_ON(!right_buffer); right = btrfs_buffer_leaf(right_buffer); memset(&right->header, 0, sizeof(right->header)); btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer)); btrfs_set_header_generation(&right->header, trans->transid); btrfs_set_header_owner(&right->header, root->root_key.objectid); btrfs_set_header_level(&right->header, 0); memcpy(right->header.fsid, root->fs_info->disk_super->fsid, sizeof(right->header.fsid)); 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, bh_blocknr(right_buffer), 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, bh_blocknr(right_buffer), 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; if (path->slots[1] == 0) { wret = fixup_low_keys(trans, root, path, &disk_key, 1); if (wret) ret = wret; } 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, bh_blocknr(right_buffer), 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, l_buf->b_blocknr); BUG_ON(!right_buffer); right = btrfs_buffer_leaf(right_buffer); memset(&right->header, 0, sizeof(right->header)); btrfs_set_header_blocknr(&right->header, bh_blocknr(right_buffer)); btrfs_set_header_generation(&right->header, trans->transid); btrfs_set_header_owner(&right->header, root->root_key.objectid); btrfs_set_header_level(&right->header, 0); memcpy(right->header.fsid, root->fs_info->disk_super->fsid, sizeof(right->header.fsid)); btrfs_cpu_key_to_disk(&disk_key, ins_key); btrfs_set_header_nritems(&right->header, 0); wret = insert_ptr(trans, root, path, &disk_key, bh_blocknr(right_buffer), path->slots[1], 1); if (wret) ret = wret; if (path->slots[1] == 0) { wret = fixup_low_keys(trans, root, path, &disk_key, 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; } int btrfs_truncate_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, u32 new_size) { int ret = 0; int slot; int slot_orig; struct btrfs_leaf *leaf; struct buffer_head *leaf_buf; u32 nritems; unsigned int data_end; unsigned int old_data_start; unsigned int old_size; unsigned int size_diff; int i; 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); slot = path->slots[0]; old_data_start = btrfs_item_offset(leaf->items + slot); old_size = btrfs_item_size(leaf->items + slot); BUG_ON(old_size <= new_size); size_diff = old_size - new_size; BUG_ON(slot < 0); BUG_ON(slot >= nritems); /* * 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 + size_diff); } /* shift the data */ btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) + data_end + size_diff, btrfs_leaf_data(leaf) + data_end, old_data_start + new_size - data_end); btrfs_set_item_size(leaf->items + slot, new_size); btrfs_mark_buffer_dirty(leaf_buf); ret = 0; if (btrfs_leaf_free_space(root, leaf) < 0) BUG(); check_leaf(root, path, 0); return ret; } int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, 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; unsigned int old_data; unsigned int old_size; int i; 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) < data_size) BUG(); slot = path->slots[0]; old_data = btrfs_item_end(leaf->items + slot); BUG_ON(slot < 0); BUG_ON(slot >= nritems); /* * 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 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; old_size = btrfs_item_size(leaf->items + slot); btrfs_set_item_size(leaf->items + slot, old_size + data_size); btrfs_mark_buffer_dirty(leaf_buf); ret = 0; if (btrfs_leaf_free_space(root, leaf) < 0) BUG(); 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, bh_blocknr(leaf_buf), 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 = bh_blocknr(leaf_buf); 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; }