Btrfs: early extent mapping support
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
David Woodhouse
parent
74123bd72a
commit
d97e63b69e
5 changed files with 236 additions and 33 deletions
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@ -4,8 +4,8 @@ CFLAGS= -g -Wall
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.c.o:
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$(CC) $(CFLAGS) -c $<
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ctree: ctree.o disk-io.h ctree.h disk-io.o radix-tree.o radix-tree.h
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gcc $(CFLAGS) -o ctree ctree.o disk-io.o radix-tree.o
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ctree: ctree.o disk-io.h ctree.h disk-io.o radix-tree.o radix-tree.h mkfs.o
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gcc $(CFLAGS) -o ctree ctree.o disk-io.o radix-tree.o mkfs.o
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clean:
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rm ctree *.o
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152
fs/btrfs/ctree.c
152
fs/btrfs/ctree.c
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@ -5,6 +5,8 @@
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#include "ctree.h"
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#include "disk-io.h"
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static int refill_alloc_extent(struct ctree_root *root);
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static inline void init_path(struct ctree_path *p)
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{
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memset(p, 0, sizeof(*p));
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@ -29,7 +31,7 @@ static inline unsigned int leaf_data_end(struct leaf *leaf)
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{
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unsigned int nr = leaf->header.nritems;
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if (nr == 0)
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return ARRAY_SIZE(leaf->data);
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return sizeof(leaf->data);
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return leaf->items[nr-1].offset;
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}
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@ -421,7 +423,7 @@ int insert_ptr(struct ctree_root *root,
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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, ARRAY_SIZE(bal));
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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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c = &t->node;
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if (push_node_left(root, path,
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@ -756,6 +758,7 @@ int insert_item(struct ctree_root *root, struct key *key,
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if (leaf_free_space(leaf) < 0)
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BUG();
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release_path(root, &path);
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refill_alloc_extent(root);
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return 0;
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}
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@ -884,6 +887,135 @@ int del_item(struct ctree_root *root, struct ctree_path *path)
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return 0;
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}
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int next_leaf(struct ctree_root *root, struct ctree_path *path)
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{
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int slot;
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int level = 1;
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u64 blocknr;
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struct tree_buffer *c;
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struct tree_buffer *next;
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while(level < MAX_LEVEL) {
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if (!path->nodes[level])
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return -1;
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slot = path->slots[level] + 1;
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c = path->nodes[level];
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if (slot >= c->node.header.nritems) {
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level++;
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continue;
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}
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blocknr = c->node.blockptrs[slot];
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next = read_tree_block(root, blocknr);
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break;
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}
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path->slots[level] = slot;
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while(1) {
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level--;
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c = path->nodes[level];
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tree_block_release(root, c);
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path->nodes[level] = next;
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path->slots[level] = 0;
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if (!level)
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break;
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next = read_tree_block(root, next->node.blockptrs[0]);
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}
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return 0;
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}
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int alloc_extent(struct ctree_root *root, u64 num_blocks, u64 search_start,
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u64 search_end, u64 owner, struct key *ins)
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{
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struct ctree_path path;
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struct key *key;
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int ret;
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u64 hole_size = 0;
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int slot = 0;
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u64 last_block;
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int start_found = 0;
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struct leaf *l;
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struct extent_item extent_item;
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init_path(&path);
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ins->objectid = 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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while (1) {
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l = &path.nodes[0]->leaf;
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slot = path.slots[0];
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if (!l) {
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// FIXME allocate root
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}
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if (slot >= l->header.nritems) {
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ret = next_leaf(root, &path);
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if (ret == 0)
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continue;
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if (!start_found) {
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ins->objectid = search_start;
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ins->offset = num_blocks;
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hole_size = search_end - search_start;
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goto insert;
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}
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ins->objectid = last_block;
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ins->offset = num_blocks;
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hole_size = search_end - last_block;
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goto insert;
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}
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key = &l->items[slot].key;
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if (start_found) {
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hole_size = key->objectid - last_block;
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if (hole_size > num_blocks) {
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ins->objectid = last_block;
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ins->offset = num_blocks;
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goto insert;
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}
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} else
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start_found = 1;
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last_block = key->objectid + key->offset;
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path.slots[0]++;
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printf("last block is not %lu\n", last_block);
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}
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// FIXME -ENOSPC
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insert:
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extent_item.refs = 1;
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extent_item.owner = owner;
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ret = insert_item(root, ins, &extent_item, sizeof(extent_item));
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return ret;
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}
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static int refill_alloc_extent(struct ctree_root *root)
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{
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struct alloc_extent *ae = root->alloc_extent;
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struct key key;
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int ret;
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int min_blocks = MAX_LEVEL * 2;
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printf("refill alloc root %p, numused %lu total %lu\n", root, ae->num_used, ae->num_blocks);
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if (ae->num_blocks > ae->num_used && ae->num_blocks - ae->num_used >
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min_blocks)
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return 0;
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ae = root->reserve_extent;
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if (ae->num_blocks > ae->num_used) {
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if (root->alloc_extent->num_blocks == 0) {
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/* we should swap reserve/alloc_extent when alloc
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* fills up
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*/
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BUG();
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}
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if (ae->num_blocks - ae->num_used < min_blocks)
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BUG();
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return 0;
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}
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// FIXME, this recurses
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ret = alloc_extent(root->extent_root,
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min_blocks * 2, 0, (unsigned long)-1, 0, &key);
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ae->blocknr = key.objectid;
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ae->num_blocks = key.offset;
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ae->num_used = 0;
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return ret;
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}
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void print_leaf(struct leaf *l)
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{
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int i;
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@ -948,8 +1080,8 @@ 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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@ -960,7 +1092,7 @@ int main() {
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int i;
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int num;
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int ret;
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int run_size = 25000;
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int run_size = 256;
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int max_key = 100000000;
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int tree_size = 0;
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struct ctree_path path;
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@ -980,10 +1112,20 @@ int main() {
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ins.objectid = num;
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ins.offset = 0;
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ins.flags = 0;
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printf("insert %d\n", i);
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ret = insert_item(root, &ins, buf, strlen(buf));
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if (!ret)
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tree_size++;
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printf("done insert %d\n", i);
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}
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printf("root used: %lu\n", root->alloc_extent->num_used);
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printf("root tree\n");
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print_tree(root, root->node);
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printf("map tree\n");
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printf("map used: %lu\n", root->extent_root->alloc_extent->num_used);
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print_tree(root->extent_root, root->extent_root->node);
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exit(1);
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close_ctree(root);
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root = open_ctree("dbfile");
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printf("starting search\n");
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@ -1,7 +1,7 @@
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#ifndef __CTREE__
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#define __CTREE__
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#define CTREE_BLOCKSIZE 4096
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#define CTREE_BLOCKSIZE 256
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struct key {
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u64 objectid;
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@ -22,18 +22,41 @@ struct header {
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#define NODEPTRS_PER_BLOCK ((CTREE_BLOCKSIZE - sizeof(struct header)) / \
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(sizeof(struct key) + sizeof(u64)))
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#define LEVEL_BITS 3
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#define MAX_LEVEL (1 << LEVEL_BITS)
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#define MAX_LEVEL 8
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#define node_level(f) ((f) & (MAX_LEVEL-1))
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#define is_leaf(f) (node_level(f) == 0)
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struct tree_buffer;
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struct alloc_extent {
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u64 blocknr;
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u64 num_blocks;
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u64 num_used;
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} __attribute__ ((__packed__));
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struct ctree_root {
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struct tree_buffer *node;
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struct ctree_root *extent_root;
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struct alloc_extent *alloc_extent;
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struct alloc_extent *reserve_extent;
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int fp;
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struct radix_tree_root cache_radix;
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struct alloc_extent ai1;
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struct alloc_extent ai2;
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};
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struct ctree_root_info {
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u64 fsid[2]; /* FS specific uuid */
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u64 blocknr; /* blocknr of this block */
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u64 objectid; /* inode number of this root */
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u64 tree_root; /* the tree root */
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u32 csum;
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u32 ham;
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struct alloc_extent alloc_extent;
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struct alloc_extent reserve_extent;
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u64 snapuuid[2]; /* root specific uuid */
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} __attribute__ ((__packed__));
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struct item {
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struct key key;
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u16 offset;
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@ -55,6 +78,11 @@ struct node {
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u64 blockptrs[NODEPTRS_PER_BLOCK];
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} __attribute__ ((__packed__));
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struct extent_item {
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u32 refs;
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u64 owner;
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} __attribute__ ((__packed__));
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struct ctree_path {
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struct tree_buffer *nodes[MAX_LEVEL];
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int slots[MAX_LEVEL];
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@ -12,25 +12,27 @@
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static int allocated_blocks = 0;
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struct ctree_header {
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u64 root_block;
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} __attribute__ ((__packed__));
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static int get_free_block(struct ctree_root *root, u64 *block)
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{
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struct stat st;
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int ret;
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if (root->alloc_extent->num_used >= root->alloc_extent->num_blocks)
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return -1;
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*block = root->alloc_extent->blocknr + root->alloc_extent->num_used;
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root->alloc_extent->num_used += 1;
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if (root->alloc_extent->num_used >= root->alloc_extent->num_blocks) {
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struct alloc_extent *ae = root->alloc_extent;
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root->alloc_extent = root->reserve_extent;
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root->reserve_extent = ae;
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ae->num_blocks = 0;
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}
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st.st_size = 0;
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ret = fstat(root->fp, &st);
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if (st.st_size > sizeof(struct ctree_header)) {
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*block = (st.st_size -
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sizeof(struct ctree_header)) / CTREE_BLOCKSIZE;
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} else {
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*block = 0;
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}
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ret = ftruncate(root->fp, sizeof(struct ctree_header) + (*block + 1) *
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CTREE_BLOCKSIZE);
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if (st.st_size < (*block + 1) * CTREE_BLOCKSIZE)
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ret = ftruncate(root->fp,
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(*block + 1) * CTREE_BLOCKSIZE);
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return ret;
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}
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@ -72,7 +74,7 @@ struct tree_buffer *alloc_free_block(struct ctree_root *root)
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struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr)
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{
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loff_t offset = blocknr * CTREE_BLOCKSIZE + sizeof(struct ctree_header);
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loff_t offset = blocknr * CTREE_BLOCKSIZE;
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struct tree_buffer *buf;
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int ret;
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@ -101,7 +103,7 @@ struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr)
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int write_tree_block(struct ctree_root *root, struct tree_buffer *buf)
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{
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u64 blocknr = buf->blocknr;
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loff_t offset = blocknr * CTREE_BLOCKSIZE + sizeof(struct ctree_header);
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loff_t offset = blocknr * CTREE_BLOCKSIZE;
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int ret;
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if (buf->blocknr != buf->node.header.blocknr)
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@ -114,11 +116,32 @@ int write_tree_block(struct ctree_root *root, struct tree_buffer *buf)
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return 0;
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}
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struct ctree_super_block {
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struct ctree_root_info root_info;
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struct ctree_root_info extent_info;
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} __attribute__ ((__packed__));
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static int __setup_root(struct ctree_root *root, struct ctree_root *extent_root,
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struct ctree_root_info *info, int fp)
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{
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root->fp = fp;
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root->node = read_tree_block(root, info->tree_root);
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root->extent_root = extent_root;
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memcpy(&root->ai1, &info->alloc_extent, sizeof(info->alloc_extent));
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memcpy(&root->ai2, &info->reserve_extent, sizeof(info->reserve_extent));
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root->alloc_extent = &root->ai1;
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root->reserve_extent = &root->ai2;
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INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL);
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printf("setup done reading root %p, used %lu\n", root, root->alloc_extent->num_used);
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return 0;
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}
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struct ctree_root *open_ctree(char *filename)
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{
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struct ctree_root *root = malloc(sizeof(struct ctree_root));
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struct ctree_root *extent_root = malloc(sizeof(struct ctree_root));
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struct ctree_super_block super;
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int fp;
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u64 root_block;
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int ret;
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fp = open(filename, O_CREAT | O_RDWR);
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@ -126,14 +149,20 @@ struct ctree_root *open_ctree(char *filename)
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free(root);
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return NULL;
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}
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root->fp = fp;
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INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL);
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ret = pread(fp, &root_block, sizeof(u64), 0);
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if (ret == sizeof(u64)) {
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printf("reading root node at block %lu\n", root_block);
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root->node = read_tree_block(root, root_block);
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} else
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root->node = NULL;
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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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ret = mkfs(fp);
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if (ret)
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return NULL;
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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 != sizeof(struct ctree_super_block))
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return NULL;
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}
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BUG_ON(ret < 0);
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__setup_root(root, extent_root, &super.root_info, fp);
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__setup_root(extent_root, extent_root, &super.extent_info, fp);
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return root;
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}
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@ -160,6 +189,7 @@ int update_root_block(struct ctree_root *root)
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void tree_block_release(struct ctree_root *root, struct tree_buffer *buf)
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{
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return;
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buf->count--;
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if (buf->count == 0) {
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if (!radix_tree_lookup(&root->cache_radix, buf->blocknr))
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@ -17,5 +17,8 @@ int close_ctree(struct ctree_root *root);
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void tree_block_release(struct ctree_root *root, struct tree_buffer *buf);
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struct tree_buffer *alloc_free_block(struct ctree_root *root);
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int update_root_block(struct ctree_root *root);
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int mkfs(int fd);
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#define CTREE_SUPER_INFO_OFFSET(bs) (16 * (bs))
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#endif
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