Btrfs: switch to early splits
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
David Woodhouse
Родитель
cfaa72952f
Коммит
5c680ed620
227
fs/btrfs/ctree.c
227
fs/btrfs/ctree.c
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@ -5,7 +5,12 @@
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#include "ctree.h"
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#include "disk-io.h"
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#define SEARCH_READ 0
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#define SEARCH_WRITE 1
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static int refill_alloc_extent(struct ctree_root *root);
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int split_node(struct ctree_root *root, struct ctree_path *path, int level);
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int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size);
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static inline void init_path(struct ctree_path *p)
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{
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@ -125,14 +130,14 @@ int bin_search(struct node *c, struct key *key, int *slot)
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* If the key isn't found, the path points to the slot where it should
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* be inserted.
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*/
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int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p)
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int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p, int ins_len)
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{
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struct tree_buffer *b = root->node;
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struct node *c;
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int slot;
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int ret;
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int level;
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b->count++;
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while (b) {
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c = &b->node;
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@ -143,10 +148,26 @@ int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p)
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if (ret && slot > 0)
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slot -= 1;
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p->slots[level] = slot;
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if (ins_len && c->header.nritems == NODEPTRS_PER_BLOCK) {
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int sret = split_node(root, p, level);
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BUG_ON(sret > 0);
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if (sret)
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return sret;
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b = p->nodes[level];
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c = &b->node;
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slot = p->slots[level];
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}
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b = read_tree_block(root, c->blockptrs[slot]);
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continue;
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} else {
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struct leaf *l = (struct leaf *)c;
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p->slots[level] = slot;
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if (ins_len && leaf_free_space(l) < sizeof(struct item) + ins_len) {
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int sret = split_leaf(root, p, ins_len);
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BUG_ON(sret > 0);
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if (sret)
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return sret;
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}
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return ret;
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}
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}
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@ -331,27 +352,20 @@ int push_node_right(struct ctree_root *root, struct ctree_path *path, int level)
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return 0;
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}
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/*
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* worker function to insert a single pointer in a node.
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* the node should have enough room for the pointer already
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* slot and level indicate where you want the key to go, and
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* blocknr is the block the key points to.
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*/
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int __insert_ptr(struct ctree_root *root,
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struct ctree_path *path, struct key *key,
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u64 blocknr, int slot, int level)
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static int insert_new_root(struct ctree_root *root, struct ctree_path *path, int level)
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{
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struct node *c;
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struct node *lower;
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struct key *lower_key;
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int nritems;
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/* need a new root */
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if (!path->nodes[level]) {
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struct tree_buffer *t;
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struct node *lower;
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struct node *c;
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struct key *lower_key;
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BUG_ON(path->nodes[level]);
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BUG_ON(path->nodes[level-1] != root->node);
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t = alloc_free_block(root);
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c = &t->node;
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memset(c, 0, sizeof(c));
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c->header.nritems = 2;
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c->header.nritems = 1;
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c->header.flags = node_level(level);
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c->header.blocknr = t->blocknr;
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c->header.parentid = root->node->node.header.parentid;
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@ -361,9 +375,7 @@ int __insert_ptr(struct ctree_root *root,
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else
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lower_key = lower->keys;
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memcpy(c->keys, lower_key, sizeof(struct key));
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memcpy(c->keys + 1, key, sizeof(struct key));
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c->blockptrs[0] = path->nodes[level-1]->blocknr;
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c->blockptrs[1] = blocknr;
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/* the super has an extra ref to root->node */
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tree_block_release(root, root->node);
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root->node = t;
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@ -371,10 +383,23 @@ int __insert_ptr(struct ctree_root *root,
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write_tree_block(root, t);
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path->nodes[level] = t;
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path->slots[level] = 0;
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if (c->keys[1].objectid == 0)
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BUG();
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return 0;
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}
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}
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/*
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* worker function to insert a single pointer in a node.
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* the node should have enough room for the pointer already
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* slot and level indicate where you want the key to go, and
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* blocknr is the block the key points to.
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*/
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int insert_ptr(struct ctree_root *root,
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struct ctree_path *path, struct key *key,
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u64 blocknr, int slot, int level)
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{
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struct node *lower;
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int nritems;
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BUG_ON(!path->nodes[level]);
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lower = &path->nodes[level]->node;
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nritems = lower->header.nritems;
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if (slot > nritems)
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@ -396,93 +421,54 @@ int __insert_ptr(struct ctree_root *root,
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return 0;
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}
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/*
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* insert a key,blocknr pair into the tree at a given level
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* If the node at that level in the path doesn't have room,
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* it is split or shifted as appropriate.
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*/
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int insert_ptr(struct ctree_root *root,
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struct ctree_path *path, struct key *key,
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u64 blocknr, int level)
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int split_node(struct ctree_root *root, struct ctree_path *path, int level)
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{
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struct tree_buffer *t = path->nodes[level];
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struct node *c = &path->nodes[level]->node;
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struct node *b;
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struct tree_buffer *b_buffer;
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struct tree_buffer *bal[MAX_LEVEL];
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int bal_level = level;
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struct tree_buffer *t;
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struct node *c;
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struct tree_buffer *split_buffer;
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struct node *split;
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int mid;
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int bal_start = -1;
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int ret;
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/*
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* check to see if we need to make room in the node for this
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* pointer. If we do, keep walking the tree, making sure there
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* is enough room in each level for the required insertions.
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*
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* The bal array is filled in with any nodes to be inserted
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* due to splitting. Once we've done all the splitting required
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* do the inserts based on the data in the bal array.
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*/
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memset(bal, 0, sizeof(bal));
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while(t && t->node.header.nritems == NODEPTRS_PER_BLOCK) {
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ret = push_node_left(root, path, level);
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if (!ret)
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return 0;
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ret = push_node_right(root, path, level);
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if (!ret)
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return 0;
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t = path->nodes[level];
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c = &t->node;
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if (push_node_left(root, path,
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node_level(c->header.flags)) == 0)
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break;
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if (push_node_right(root, path,
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node_level(c->header.flags)) == 0)
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break;
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bal_start = bal_level;
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if (bal_level == MAX_LEVEL - 1)
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BUG();
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b_buffer = alloc_free_block(root);
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b = &b_buffer->node;
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b->header.flags = c->header.flags;
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b->header.blocknr = b_buffer->blocknr;
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b->header.parentid = root->node->node.header.parentid;
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if (t == root->node) {
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/* trying to split the root, lets make a new one */
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ret = insert_new_root(root, path, level + 1);
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if (ret)
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return ret;
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}
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split_buffer = alloc_free_block(root);
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split = &split_buffer->node;
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split->header.flags = c->header.flags;
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split->header.blocknr = split_buffer->blocknr;
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split->header.parentid = root->node->node.header.parentid;
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mid = (c->header.nritems + 1) / 2;
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memcpy(b->keys, c->keys + mid,
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memcpy(split->keys, c->keys + mid,
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(c->header.nritems - mid) * sizeof(struct key));
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memcpy(b->blockptrs, c->blockptrs + mid,
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memcpy(split->blockptrs, c->blockptrs + mid,
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(c->header.nritems - mid) * sizeof(u64));
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b->header.nritems = c->header.nritems - mid;
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split->header.nritems = c->header.nritems - mid;
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c->header.nritems = mid;
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write_tree_block(root, t);
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write_tree_block(root, b_buffer);
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bal[bal_level] = b_buffer;
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if (bal_level == MAX_LEVEL - 1)
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break;
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bal_level += 1;
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t = path->nodes[bal_level];
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}
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/*
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* bal_start tells us the first level in the tree that needed to
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* be split. Go through the bal array inserting the new nodes
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* as needed. The path is fixed as we go.
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*/
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while(bal_start > 0) {
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b_buffer = bal[bal_start];
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c = &path->nodes[bal_start]->node;
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__insert_ptr(root, path, b_buffer->node.keys, b_buffer->blocknr,
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path->slots[bal_start + 1] + 1, bal_start + 1);
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if (path->slots[bal_start] >= c->header.nritems) {
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path->slots[bal_start] -= c->header.nritems;
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tree_block_release(root, path->nodes[bal_start]);
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path->nodes[bal_start] = b_buffer;
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path->slots[bal_start + 1] += 1;
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write_tree_block(root, split_buffer);
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insert_ptr(root, path, split->keys, split_buffer->blocknr,
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path->slots[level + 1] + 1, level + 1);
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if (path->slots[level] > mid) {
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path->slots[level] -= mid;
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tree_block_release(root, t);
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path->nodes[level] = split_buffer;
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path->slots[level + 1] += 1;
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} else {
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tree_block_release(root, b_buffer);
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tree_block_release(root, split_buffer);
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}
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bal_start--;
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if (!bal[bal_start])
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break;
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}
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/* Now that the tree has room, insert the requested pointer */
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return __insert_ptr(root, path, key, blocknr, path->slots[level] + 1,
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level);
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return 0;
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}
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/*
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@ -623,6 +609,11 @@ int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size)
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if (leaf_free_space(l) >= sizeof(struct item) + data_size)
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return 0;
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}
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if (!path->nodes[1]) {
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ret = insert_new_root(root, path, 1);
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if (ret)
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return ret;
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}
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slot = path->slots[0];
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nritems = l->header.nritems;
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mid = (nritems + 1)/ 2;
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@ -659,8 +650,7 @@ int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size)
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l->header.nritems = mid;
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ret = insert_ptr(root, path, &right->items[0].key,
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right_buffer->blocknr, 1);
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right_buffer->blocknr, path->slots[1] + 1, 1);
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write_tree_block(root, right_buffer);
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write_tree_block(root, l_buf);
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@ -695,21 +685,10 @@ int insert_item(struct ctree_root *root, struct key *key,
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refill_alloc_extent(root);
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/* create a root if there isn't one */
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if (!root->node) {
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if (!root->node)
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BUG();
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#if 0
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struct tree_buffer *t;
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t = alloc_free_block(root);
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BUG_ON(!t);
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t->node.header.nritems = 0;
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t->node.header.flags = node_level(0);
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t->node.header.blocknr = t->blocknr;
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root->node = t;
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write_tree_block(root, t);
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#endif
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}
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init_path(&path);
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ret = search_slot(root, key, &path);
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ret = search_slot(root, key, &path, data_size);
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if (ret == 0) {
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release_path(root, &path);
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return -EEXIST;
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@ -719,12 +698,6 @@ int insert_item(struct ctree_root *root, struct key *key,
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leaf_buf = path.nodes[0];
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leaf = &leaf_buf->leaf;
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/* make room if needed */
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if (leaf_free_space(leaf) < sizeof(struct item) + data_size) {
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split_leaf(root, &path, data_size);
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leaf_buf = path.nodes[0];
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leaf = &path.nodes[0]->leaf;
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}
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nritems = leaf->header.nritems;
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data_end = leaf_data_end(leaf);
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@ -950,7 +923,7 @@ int alloc_extent(struct ctree_root *orig_root, u64 num_blocks, u64 search_start,
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ins->offset = 0;
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ins->flags = 0;
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ret = search_slot(root, ins, &path);
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ret = search_slot(root, ins, &path, sizeof(struct extent_item));
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while (1) {
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l = &path.nodes[0]->leaf;
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slot = path.slots[0];
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@ -1097,8 +1070,8 @@ void print_tree(struct ctree_root *root, struct tree_buffer *t)
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/* for testing only */
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int next_key(int i, int max_key) {
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return rand() % max_key;
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// return i;
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// return rand() % max_key;
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return i;
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}
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int main() {
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@ -1154,7 +1127,7 @@ int main() {
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num = next_key(i, max_key);
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ins.objectid = num;
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init_path(&path);
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ret = search_slot(root, &ins, &path);
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ret = search_slot(root, &ins, &path, 0);
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if (ret) {
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print_tree(root, root->node);
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printf("unable to find %d\n", num);
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@ -1176,7 +1149,7 @@ int main() {
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num = next_key(i, max_key);
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ins.objectid = num;
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init_path(&path);
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ret = search_slot(root, &ins, &path);
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ret = search_slot(root, &ins, &path, 0);
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if (ret)
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continue;
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ret = del_item(root, &path);
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@ -1204,7 +1177,7 @@ int main() {
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num = next_key(i, max_key);
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ins.objectid = num;
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init_path(&path);
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ret = search_slot(root, &ins, &path);
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ret = search_slot(root, &ins, &path, 0);
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if (ret) {
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print_tree(root, root->node);
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printf("unable to find %d\n", num);
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@ -1218,7 +1191,7 @@ int main() {
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int slot;
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ins.objectid = (u64)-1;
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init_path(&path);
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ret = search_slot(root, &ins, &path);
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ret = search_slot(root, &ins, &path, 0);
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if (ret == 0)
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BUG();
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@ -149,7 +149,8 @@ struct ctree_root *open_ctree(char *filename, struct ctree_super_block *super)
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}
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ret = pread(fp, super, sizeof(struct ctree_super_block),
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CTREE_SUPER_INFO_OFFSET(CTREE_BLOCKSIZE));
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if (ret == 0) {
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if (ret == 0 || super->root_info.tree_root == 0) {
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printf("making new FS!\n");
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ret = mkfs(fp);
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if (ret)
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return NULL;
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