From: Chris Mason Date: Thu, 22 Feb 2007 16:39:13 +0000 (-0500) Subject: Btrfs: switch to early splits X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=5c680ed620c2b69cf751aecf1a5e03ce2c89c7f3;p=linux-beck.git Btrfs: switch to early splits Signed-off-by: Chris Mason --- diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 2891b582e26f..1b4e82d8074d 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -5,7 +5,12 @@ #include "ctree.h" #include "disk-io.h" +#define SEARCH_READ 0 +#define SEARCH_WRITE 1 + static int refill_alloc_extent(struct ctree_root *root); +int split_node(struct ctree_root *root, struct ctree_path *path, int level); +int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size); static inline void init_path(struct ctree_path *p) { @@ -125,14 +130,14 @@ int bin_search(struct node *c, struct key *key, int *slot) * If the key isn't found, the path points to the slot where it should * be inserted. */ -int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p) +int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p, int ins_len) { struct tree_buffer *b = root->node; struct node *c; - int slot; int ret; int level; + b->count++; while (b) { c = &b->node; @@ -143,10 +148,26 @@ int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p) if (ret && slot > 0) slot -= 1; p->slots[level] = slot; + if (ins_len && c->header.nritems == NODEPTRS_PER_BLOCK) { + int sret = split_node(root, p, level); + BUG_ON(sret > 0); + if (sret) + return sret; + b = p->nodes[level]; + c = &b->node; + slot = p->slots[level]; + } b = read_tree_block(root, c->blockptrs[slot]); continue; } else { + struct leaf *l = (struct leaf *)c; p->slots[level] = slot; + if (ins_len && leaf_free_space(l) < sizeof(struct item) + ins_len) { + int sret = split_leaf(root, p, ins_len); + BUG_ON(sret > 0); + if (sret) + return sret; + } return ret; } } @@ -331,50 +352,54 @@ int push_node_right(struct ctree_root *root, struct ctree_path *path, int level) return 0; } +static int insert_new_root(struct ctree_root *root, struct ctree_path *path, int level) +{ + struct tree_buffer *t; + struct node *lower; + struct node *c; + struct key *lower_key; + + BUG_ON(path->nodes[level]); + BUG_ON(path->nodes[level-1] != root->node); + + t = alloc_free_block(root); + c = &t->node; + memset(c, 0, sizeof(c)); + c->header.nritems = 1; + c->header.flags = node_level(level); + c->header.blocknr = t->blocknr; + c->header.parentid = root->node->node.header.parentid; + lower = &path->nodes[level-1]->node; + if (is_leaf(lower->header.flags)) + lower_key = &((struct leaf *)lower)->items[0].key; + else + lower_key = lower->keys; + memcpy(c->keys, lower_key, sizeof(struct key)); + c->blockptrs[0] = path->nodes[level-1]->blocknr; + /* the super has an extra ref to root->node */ + tree_block_release(root, root->node); + root->node = t; + t->count++; + write_tree_block(root, 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. */ -int __insert_ptr(struct ctree_root *root, +int insert_ptr(struct ctree_root *root, struct ctree_path *path, struct key *key, u64 blocknr, int slot, int level) { - struct node *c; struct node *lower; - struct key *lower_key; int nritems; - /* need a new root */ - if (!path->nodes[level]) { - struct tree_buffer *t; - t = alloc_free_block(root); - c = &t->node; - memset(c, 0, sizeof(c)); - c->header.nritems = 2; - c->header.flags = node_level(level); - c->header.blocknr = t->blocknr; - c->header.parentid = root->node->node.header.parentid; - lower = &path->nodes[level-1]->node; - if (is_leaf(lower->header.flags)) - lower_key = &((struct leaf *)lower)->items[0].key; - else - lower_key = lower->keys; - memcpy(c->keys, lower_key, sizeof(struct key)); - memcpy(c->keys + 1, key, sizeof(struct key)); - c->blockptrs[0] = path->nodes[level-1]->blocknr; - c->blockptrs[1] = blocknr; - /* the super has an extra ref to root->node */ - tree_block_release(root, root->node); - root->node = t; - t->count++; - write_tree_block(root, t); - path->nodes[level] = t; - path->slots[level] = 0; - if (c->keys[1].objectid == 0) - BUG(); - return 0; - } + + BUG_ON(!path->nodes[level]); lower = &path->nodes[level]->node; nritems = lower->header.nritems; if (slot > nritems) @@ -396,93 +421,54 @@ int __insert_ptr(struct ctree_root *root, return 0; } - -/* - * insert a key,blocknr pair into the tree at a given level - * If the node at that level in the path doesn't have room, - * it is split or shifted as appropriate. - */ -int insert_ptr(struct ctree_root *root, - struct ctree_path *path, struct key *key, - u64 blocknr, int level) +int split_node(struct ctree_root *root, struct ctree_path *path, int level) { - struct tree_buffer *t = path->nodes[level]; - struct node *c = &path->nodes[level]->node; - struct node *b; - struct tree_buffer *b_buffer; - struct tree_buffer *bal[MAX_LEVEL]; - int bal_level = level; + struct tree_buffer *t; + struct node *c; + struct tree_buffer *split_buffer; + struct node *split; int mid; - int bal_start = -1; - - /* - * check to see if we need to make room in the node for this - * pointer. If we do, keep walking the tree, making sure there - * is enough room in each level for the required insertions. - * - * The bal array is filled in with any nodes to be inserted - * due to splitting. Once we've done all the splitting required - * do the inserts based on the data in the bal array. - */ - memset(bal, 0, sizeof(bal)); - while(t && t->node.header.nritems == NODEPTRS_PER_BLOCK) { - c = &t->node; - if (push_node_left(root, path, - node_level(c->header.flags)) == 0) - break; - if (push_node_right(root, path, - node_level(c->header.flags)) == 0) - break; - bal_start = bal_level; - if (bal_level == MAX_LEVEL - 1) - BUG(); - b_buffer = alloc_free_block(root); - b = &b_buffer->node; - b->header.flags = c->header.flags; - b->header.blocknr = b_buffer->blocknr; - b->header.parentid = root->node->node.header.parentid; - mid = (c->header.nritems + 1) / 2; - memcpy(b->keys, c->keys + mid, - (c->header.nritems - mid) * sizeof(struct key)); - memcpy(b->blockptrs, c->blockptrs + mid, - (c->header.nritems - mid) * sizeof(u64)); - b->header.nritems = c->header.nritems - mid; - c->header.nritems = mid; - - write_tree_block(root, t); - write_tree_block(root, b_buffer); + int ret; - bal[bal_level] = b_buffer; - if (bal_level == MAX_LEVEL - 1) - break; - bal_level += 1; - t = path->nodes[bal_level]; + ret = push_node_left(root, path, level); + if (!ret) + return 0; + ret = push_node_right(root, path, level); + if (!ret) + return 0; + t = path->nodes[level]; + c = &t->node; + if (t == root->node) { + /* trying to split the root, lets make a new one */ + ret = insert_new_root(root, path, level + 1); + if (ret) + return ret; } - /* - * bal_start tells us the first level in the tree that needed to - * be split. Go through the bal array inserting the new nodes - * as needed. The path is fixed as we go. - */ - while(bal_start > 0) { - b_buffer = bal[bal_start]; - c = &path->nodes[bal_start]->node; - __insert_ptr(root, path, b_buffer->node.keys, b_buffer->blocknr, - path->slots[bal_start + 1] + 1, bal_start + 1); - if (path->slots[bal_start] >= c->header.nritems) { - path->slots[bal_start] -= c->header.nritems; - tree_block_release(root, path->nodes[bal_start]); - path->nodes[bal_start] = b_buffer; - path->slots[bal_start + 1] += 1; - } else { - tree_block_release(root, b_buffer); - } - bal_start--; - if (!bal[bal_start]) - break; + split_buffer = alloc_free_block(root); + split = &split_buffer->node; + split->header.flags = c->header.flags; + split->header.blocknr = split_buffer->blocknr; + split->header.parentid = root->node->node.header.parentid; + mid = (c->header.nritems + 1) / 2; + memcpy(split->keys, c->keys + mid, + (c->header.nritems - mid) * sizeof(struct key)); + memcpy(split->blockptrs, c->blockptrs + mid, + (c->header.nritems - mid) * sizeof(u64)); + split->header.nritems = c->header.nritems - mid; + c->header.nritems = mid; + write_tree_block(root, t); + write_tree_block(root, split_buffer); + insert_ptr(root, path, split->keys, split_buffer->blocknr, + path->slots[level + 1] + 1, level + 1); + if (path->slots[level] > mid) { + path->slots[level] -= mid; + tree_block_release(root, t); + path->nodes[level] = split_buffer; + path->slots[level + 1] += 1; + } else { + tree_block_release(root, split_buffer); } - /* Now that the tree has room, insert the requested pointer */ - return __insert_ptr(root, path, key, blocknr, path->slots[level] + 1, - level); + return 0; } /* @@ -623,6 +609,11 @@ int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size) if (leaf_free_space(l) >= sizeof(struct item) + data_size) return 0; } + if (!path->nodes[1]) { + ret = insert_new_root(root, path, 1); + if (ret) + return ret; + } slot = path->slots[0]; nritems = l->header.nritems; mid = (nritems + 1)/ 2; @@ -659,8 +650,7 @@ int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size) l->header.nritems = mid; ret = insert_ptr(root, path, &right->items[0].key, - right_buffer->blocknr, 1); - + right_buffer->blocknr, path->slots[1] + 1, 1); write_tree_block(root, right_buffer); write_tree_block(root, l_buf); @@ -695,21 +685,10 @@ int insert_item(struct ctree_root *root, struct key *key, refill_alloc_extent(root); /* create a root if there isn't one */ - if (!root->node) { + if (!root->node) BUG(); -#if 0 - struct tree_buffer *t; - t = alloc_free_block(root); - BUG_ON(!t); - t->node.header.nritems = 0; - t->node.header.flags = node_level(0); - t->node.header.blocknr = t->blocknr; - root->node = t; - write_tree_block(root, t); -#endif - } init_path(&path); - ret = search_slot(root, key, &path); + ret = search_slot(root, key, &path, data_size); if (ret == 0) { release_path(root, &path); return -EEXIST; @@ -719,12 +698,6 @@ int insert_item(struct ctree_root *root, struct key *key, leaf_buf = path.nodes[0]; leaf = &leaf_buf->leaf; - /* make room if needed */ - if (leaf_free_space(leaf) < sizeof(struct item) + data_size) { - split_leaf(root, &path, data_size); - leaf_buf = path.nodes[0]; - leaf = &path.nodes[0]->leaf; - } nritems = leaf->header.nritems; data_end = leaf_data_end(leaf); @@ -950,7 +923,7 @@ int alloc_extent(struct ctree_root *orig_root, u64 num_blocks, u64 search_start, ins->offset = 0; ins->flags = 0; - ret = search_slot(root, ins, &path); + ret = search_slot(root, ins, &path, sizeof(struct extent_item)); while (1) { l = &path.nodes[0]->leaf; slot = path.slots[0]; @@ -1097,8 +1070,8 @@ void print_tree(struct ctree_root *root, struct tree_buffer *t) /* for testing only */ int next_key(int i, int max_key) { - return rand() % max_key; - // return i; + // return rand() % max_key; + return i; } int main() { @@ -1154,7 +1127,7 @@ int main() { num = next_key(i, max_key); ins.objectid = num; init_path(&path); - ret = search_slot(root, &ins, &path); + ret = search_slot(root, &ins, &path, 0); if (ret) { print_tree(root, root->node); printf("unable to find %d\n", num); @@ -1176,7 +1149,7 @@ int main() { num = next_key(i, max_key); ins.objectid = num; init_path(&path); - ret = search_slot(root, &ins, &path); + ret = search_slot(root, &ins, &path, 0); if (ret) continue; ret = del_item(root, &path); @@ -1204,7 +1177,7 @@ int main() { num = next_key(i, max_key); ins.objectid = num; init_path(&path); - ret = search_slot(root, &ins, &path); + ret = search_slot(root, &ins, &path, 0); if (ret) { print_tree(root, root->node); printf("unable to find %d\n", num); @@ -1218,7 +1191,7 @@ int main() { int slot; ins.objectid = (u64)-1; init_path(&path); - ret = search_slot(root, &ins, &path); + ret = search_slot(root, &ins, &path, 0); if (ret == 0) BUG(); diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 2f71ccf1c3cb..a696a4278ac5 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -149,7 +149,8 @@ struct ctree_root *open_ctree(char *filename, struct ctree_super_block *super) } ret = pread(fp, super, sizeof(struct ctree_super_block), CTREE_SUPER_INFO_OFFSET(CTREE_BLOCKSIZE)); - if (ret == 0) { + if (ret == 0 || super->root_info.tree_root == 0) { + printf("making new FS!\n"); ret = mkfs(fp); if (ret) return NULL;