Btrfs: Initial checkin, basic working tree code (be0e5c09) · Commits · e / devices / android_kernel_teracube_emerald

fs/btrfs/ctree.c

0 → 100644

+810 −0

Original line number	Diff line number	Diff line
		#include <stdio.h>
		#include <stdlib.h>
		#include "kerncompat.h"

		#define BLOCKSIZE 4096

		struct key {
		u64 objectid;
		u32 flags;
		u64 offset;
		} __attribute__ ((__packed__));

		struct header {
		u64 fsid[2]; /* FS specific uuid */
		u64 blocknum;
		u64 parentid;
		u32 csum;
		u32 ham;
		u16 nritems;
		u16 flags;
		} __attribute__ ((__packed__));

		#define NODEPTRS_PER_BLOCK ((BLOCKSIZE - sizeof(struct header)) / \
		(sizeof(struct key) + sizeof(u64)))

		#define LEVEL_BITS 3
		#define MAX_LEVEL (1 << LEVEL_BITS)
		#define node_level(f) ((f) & (MAX_LEVEL-1))
		#define is_leaf(f) (node_level(f) == 0)

		struct ctree_root {
		struct node *node;
		};

		struct item {
		struct key key;
		u16 offset;
		u16 size;
		} __attribute__ ((__packed__));

		#define LEAF_DATA_SIZE (BLOCKSIZE - sizeof(struct header))
		struct leaf {
		struct header header;
		union {
		struct item items[LEAF_DATA_SIZE/sizeof(struct item)];
		u8 data[BLOCKSIZE-sizeof(struct header)];
		};
		} __attribute__ ((__packed__));

		struct node {
		struct header header;
		struct key keys[NODEPTRS_PER_BLOCK];
		u64 blockptrs[NODEPTRS_PER_BLOCK];
		} __attribute__ ((__packed__));

		struct ctree_path {
		struct node *nodes[MAX_LEVEL];
		int slots[MAX_LEVEL];
		};

		static inline void init_path(struct ctree_path *p)
		{
		memset(p, 0, sizeof(*p));
		}

		static inline unsigned int leaf_data_end(struct leaf *leaf)
		{
		unsigned int nr = leaf->header.nritems;
		if (nr == 0)
		return ARRAY_SIZE(leaf->data);
		return leaf->items[nr-1].offset;
		}

		static inline int leaf_free_space(struct leaf *leaf)
		{
		int data_end = leaf_data_end(leaf);
		int nritems = leaf->header.nritems;
		char items_end = (char )(leaf->items + nritems + 1);
		return (char )(leaf->data + data_end) - (char )items_end;
		}

		int comp_keys(struct key k1, struct key k2)
		{
		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;
		}
		int generic_bin_search(char p, int item_size, struct key key,
		int max, int *slot)
		{
		int low = 0;
		int high = max;
		int mid;
		int ret;
		struct key *tmp;

		while(low < high) {
		mid = (low + high) / 2;
		tmp = (struct 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;
		}

		int bin_search(struct node c, struct key key, int *slot)
		{
		if (is_leaf(c->header.flags)) {
		struct leaf l = (struct leaf )c;
		return generic_bin_search((void *)l->items, sizeof(struct item),
		key, c->header.nritems, slot);
		} else {
		return generic_bin_search((void *)c->keys, sizeof(struct key),
		key, c->header.nritems, slot);
		}
		return -1;
		}

		void *read_block(u64 blocknum)
		{
		return (void *)blocknum;
		}

		int search_slot(struct ctree_root root, struct key key, struct ctree_path *p)
		{
		struct node *c = root->node;
		int slot;
		int ret;
		int level;
		while (c) {
		level = node_level(c->header.flags);
		p->nodes[level] = c;
		ret = bin_search(c, key, &slot);
		if (!is_leaf(c->header.flags)) {
		if (ret && slot > 0)
		slot -= 1;
		p->slots[level] = slot;
		c = read_block(c->blockptrs[slot]);
		continue;
		} else {
		p->slots[level] = slot;
		return ret;
		}
		}
		return -1;
		}

		static void fixup_low_keys(struct ctree_path path, struct key key,
		int level)
		{
		int i;
		/* adjust the pointers going up the tree */
		for (i = level; i < MAX_LEVEL; i++) {
		struct node *t = path->nodes[i];
		int tslot = path->slots[i];
		if (!t)
		break;
		memcpy(t->keys + tslot, key, sizeof(*key));
		if (tslot != 0)
		break;
		}
		}

		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]) {
		c = malloc(sizeof(struct node));
		memset(c, 0, sizeof(c));
		c->header.nritems = 2;
		c->header.flags = node_level(level);
		lower = path->nodes[level-1];
		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] = (u64)lower;
		c->blockptrs[1] = blocknr;
		root->node = c;
		path->nodes[level] = c;
		path->slots[level] = 0;
		if (c->keys[1].objectid == 0)
		BUG();
		return 0;
		}
		lower = path->nodes[level];
		nritems = lower->header.nritems;
		if (slot > nritems)
		BUG();
		if (nritems == NODEPTRS_PER_BLOCK)
		BUG();
		if (slot != nritems) {
		memmove(lower->keys + slot + 1, lower->keys + slot,
		(nritems - slot) * sizeof(struct key));
		memmove(lower->blockptrs + slot + 1, lower->blockptrs + slot,
		(nritems - slot) * sizeof(u64));
		}
		memcpy(lower->keys + slot, key, sizeof(struct key));
		lower->blockptrs[slot] = blocknr;
		lower->header.nritems++;
		if (lower->keys[1].objectid == 0)
		BUG();
		return 0;
		}

		int push_node_left(struct ctree_root root, struct ctree_path path, int level)
		{
		int slot;
		struct node *left;
		struct node *right;
		int push_items = 0;
		int left_nritems;
		int right_nritems;

		if (level == MAX_LEVEL - 1 \|\| path->nodes[level + 1] == 0)
		return 1;
		slot = path->slots[level + 1];
		if (slot == 0)
		return 1;

		left = read_block(path->nodes[level + 1]->blockptrs[slot - 1]);
		right = path->nodes[level];
		left_nritems = left->header.nritems;
		right_nritems = right->header.nritems;
		push_items = NODEPTRS_PER_BLOCK - (left_nritems + 1);
		if (push_items <= 0)
		return 1;

		if (right_nritems < push_items)
		push_items = right_nritems;
		memcpy(left->keys + left_nritems, right->keys,
		push_items * sizeof(struct key));
		memcpy(left->blockptrs + left_nritems, right->blockptrs,
		push_items * sizeof(u64));
		memmove(right->keys, right->keys + push_items,
		(right_nritems - push_items) * sizeof(struct key));
		memmove(right->blockptrs, right->blockptrs + push_items,
		(right_nritems - push_items) * sizeof(u64));
		right->header.nritems -= push_items;
		left->header.nritems += push_items;

		/* adjust the pointers going up the tree */
		fixup_low_keys(path, right->keys, level + 1);

		/* then fixup the leaf pointer in the path */
		if (path->slots[level] < push_items) {
		path->slots[level] += left_nritems;
		path->nodes[level] = (struct node*)left;
		path->slots[level + 1] -= 1;
		} else {
		path->slots[level] -= push_items;
		}
		return 0;
		}

		int push_node_right(struct ctree_root root, struct ctree_path path, int level)
		{
		int slot;
		struct node *dst;
		struct node *src;
		int push_items = 0;
		int dst_nritems;
		int src_nritems;

		if (level == MAX_LEVEL - 1 \|\| path->nodes[level + 1] == 0)
		return 1;
		slot = path->slots[level + 1];
		if (slot == NODEPTRS_PER_BLOCK - 1)
		return 1;

		if (slot >= path->nodes[level + 1]->header.nritems -1)
		return 1;

		dst = read_block(path->nodes[level + 1]->blockptrs[slot + 1]);
		src = path->nodes[level];
		dst_nritems = dst->header.nritems;
		src_nritems = src->header.nritems;
		push_items = NODEPTRS_PER_BLOCK - (dst_nritems + 1);
		if (push_items <= 0)
		return 1;

		if (src_nritems < push_items)
		push_items = src_nritems;
		memmove(dst->keys + push_items, dst->keys,
		dst_nritems * sizeof(struct key));
		memcpy(dst->keys, src->keys + src_nritems - push_items,
		push_items * sizeof(struct key));

		memmove(dst->blockptrs + push_items, dst->blockptrs,
		dst_nritems * sizeof(u64));
		memcpy(dst->blockptrs, src->blockptrs + src_nritems - push_items,
		push_items * sizeof(u64));

		src->header.nritems -= push_items;
		dst->header.nritems += push_items;

		/* adjust the pointers going up the tree */
		memcpy(path->nodes[level + 1]->keys + path->slots[level + 1] + 1,
		dst->keys, sizeof(struct key));
		/* then fixup the leaf pointer in the path */
		if (path->slots[level] >= src->header.nritems) {
		path->slots[level] -= src->header.nritems;
		path->nodes[level] = (struct node*)dst;
		path->slots[level + 1] += 1;
		}
		return 0;
		}

		int insert_ptr(struct ctree_root *root,
		struct ctree_path path, struct key key,
		u64 blocknr, int level)
		{
		struct node *c = path->nodes[level];
		struct node *b;
		struct node *bal[MAX_LEVEL];
		int bal_level = level;
		int mid;
		int bal_start = -1;

		memset(bal, 0, ARRAY_SIZE(bal));
		while(c && c->header.nritems == NODEPTRS_PER_BLOCK) {
		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 = malloc(sizeof(struct node));
		b->header.flags = c->header.flags;
		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;
		bal[bal_level] = b;
		if (bal_level == MAX_LEVEL - 1)
		break;
		bal_level += 1;
		c = path->nodes[bal_level];
		}
		while(bal_start > 0) {
		b = bal[bal_start];
		c = path->nodes[bal_start];
		__insert_ptr(root, path, b->keys, (u64)b,
		path->slots[bal_start + 1] + 1, bal_start + 1);
		if (path->slots[bal_start] >= c->header.nritems) {
		path->slots[bal_start] -= c->header.nritems;
		path->nodes[bal_start] = b;
		path->slots[bal_start + 1] += 1;
		}
		bal_start--;
		if (!bal[bal_start])
		break;
		}
		return __insert_ptr(root, path, key, blocknr, path->slots[level] + 1,
		level);
		}

		int leaf_space_used(struct leaf *l, int start, int nr)
		{
		int data_len;
		int end = start + nr - 1;

		if (!nr)
		return 0;
		data_len = l->items[start].offset + l->items[start].size;
		data_len = data_len - l->items[end].offset;
		data_len += sizeof(struct item) * nr;
		return data_len;
		}

		int push_leaf_left(struct ctree_root root, struct ctree_path path,
		int data_size)
		{
		struct leaf right = (struct leaf )path->nodes[0];
		struct leaf *left;
		int slot;
		int i;
		int free_space;
		int push_space = 0;
		int push_items = 0;
		struct item *item;
		int old_left_nritems;

		slot = path->slots[1];
		if (slot == 0) {
		return 1;
		}
		if (!path->nodes[1]) {
		return 1;
		}
		left = read_block(path->nodes[1]->blockptrs[slot - 1]);
		free_space = leaf_free_space(left);
		if (free_space < data_size + sizeof(struct item)) {
		return 1;
		}
		for (i = 0; i < right->header.nritems; i++) {
		item = right->items + i;
		if (path->slots[0] == i)
		push_space += data_size + sizeof(*item);
		if (item->size + sizeof(*item) + push_space > free_space)
		break;
		push_items++;
		push_space += item->size + sizeof(*item);
		}
		if (push_items == 0) {
		return 1;
		}
		/* push data from right to left */
		memcpy(left->items + left->header.nritems,
		right->items, push_items * sizeof(struct item));
		push_space = LEAF_DATA_SIZE - right->items[push_items -1].offset;
		memcpy(left->data + leaf_data_end(left) - push_space,
		right->data + right->items[push_items - 1].offset,
		push_space);
		old_left_nritems = left->header.nritems;
		for(i = old_left_nritems; i < old_left_nritems + push_items; i++) {
		left->items[i].offset -= LEAF_DATA_SIZE -
		left->items[old_left_nritems -1].offset;
		}
		left->header.nritems += push_items;

		/* fixup right node */
		push_space = right->items[push_items-1].offset - leaf_data_end(right);
		memmove(right->data + LEAF_DATA_SIZE - push_space, right->data +
		leaf_data_end(right), push_space);
		memmove(right->items, right->items + push_items,
		(right->header.nritems - push_items) * sizeof(struct item));
		right->header.nritems -= push_items;
		push_space = LEAF_DATA_SIZE;
		for (i = 0; i < right->header.nritems; i++) {
		right->items[i].offset = push_space - right->items[i].size;
		push_space = right->items[i].offset;
		}
		fixup_low_keys(path, &right->items[0].key, 1);

		/* then fixup the leaf pointer in the path */
		if (path->slots[0] < push_items) {
		path->slots[0] += old_left_nritems;
		path->nodes[0] = (struct node*)left;
		path->slots[1] -= 1;
		} else {
		path->slots[0] -= push_items;
		}
		return 0;
		}

		int split_leaf(struct ctree_root root, struct ctree_path path, int data_size)
		{
		struct leaf l = (struct leaf )path->nodes[0];
		int nritems = l->header.nritems;
		int mid = (nritems + 1)/ 2;
		int slot = path->slots[0];
		struct leaf *right;
		int space_needed = data_size + sizeof(struct item);
		int data_copy_size;
		int rt_data_off;
		int i;
		int ret;

		if (push_leaf_left(root, path, data_size) == 0) {
		return 0;
		}
		right = malloc(sizeof(struct leaf));
		memset(right, 0, sizeof(*right));
		if (mid <= slot) {
		if (leaf_space_used(l, mid, nritems - mid) + space_needed >
		LEAF_DATA_SIZE)
		BUG();
		} else {
		if (leaf_space_used(l, 0, mid + 1) + space_needed >
		LEAF_DATA_SIZE)
		BUG();
		}
		right->header.nritems = nritems - mid;
		data_copy_size = l->items[mid].offset + l->items[mid].size -
		leaf_data_end(l);
		memcpy(right->items, l->items + mid,
		(nritems - mid) * sizeof(struct item));
		memcpy(right->data + LEAF_DATA_SIZE - data_copy_size,
		l->data + leaf_data_end(l), data_copy_size);
		rt_data_off = LEAF_DATA_SIZE -
		(l->items[mid].offset + l->items[mid].size);
		for (i = 0; i < right->header.nritems; i++) {
		right->items[i].offset += rt_data_off;
		}
		l->header.nritems = mid;
		ret = insert_ptr(root, path, &right->items[0].key,
		(u64)right, 1);
		if (mid <= slot) {
		path->nodes[0] = (struct node *)right;
		path->slots[0] -= mid;
		path->slots[1] += 1;
		}
		return ret;
		}

		int insert_item(struct ctree_root root, struct key key,
		void *data, int data_size)
		{
		int ret;
		int slot;
		struct leaf *leaf;
		unsigned int nritems;
		unsigned int data_end;
		struct ctree_path path;

		init_path(&path);
		ret = search_slot(root, key, &path);
		if (ret == 0)
		return -EEXIST;

		leaf = (struct leaf *)path.nodes[0];
		if (leaf_free_space(leaf) < sizeof(struct item) + data_size)
		split_leaf(root, &path, data_size);
		leaf = (struct leaf *)path.nodes[0];
		nritems = leaf->header.nritems;
		data_end = leaf_data_end(leaf);
		if (leaf_free_space(leaf) < sizeof(struct item) + data_size)
		BUG();

		slot = path.slots[0];
		if (slot == 0)
		fixup_low_keys(&path, key, 1);
		if (slot != nritems) {
		int i;
		unsigned int old_data = leaf->items[slot].offset +
		leaf->items[slot].size;

		/*
		* item0..itemN ... dataN.offset..dataN.size .. data0.size
		*/
		/* first correct the data pointers */
		for (i = slot; i < nritems; i++)
		leaf->items[i].offset -= data_size;

		/* shift the items */
		memmove(leaf->items + slot + 1, leaf->items + slot,
		(nritems - slot) * sizeof(struct item));

		/* shift the data */
		memmove(leaf->data + data_end - data_size, leaf->data +
		data_end, old_data - data_end);
		data_end = old_data;
		}
		memcpy(&leaf->items[slot].key, key, sizeof(struct key));
		leaf->items[slot].offset = data_end - data_size;
		leaf->items[slot].size = data_size;
		memcpy(leaf->data + data_end - data_size, data, data_size);
		leaf->header.nritems += 1;
		if (leaf_free_space(leaf) < 0)
		BUG();
		return 0;
		}

		int del_ptr(struct ctree_root root, struct ctree_path path, int level)
		{
		int slot;
		struct node *node;
		int nritems;

		while(1) {
		node = path->nodes[level];
		if (!node)
		break;
		slot = path->slots[level];
		nritems = node->header.nritems;

		if (slot != nritems -1) {
		memmove(node->keys + slot, node->keys + slot + 1,
		sizeof(struct key) * (nritems - slot - 1));
		memmove(node->blockptrs + slot,
		node->blockptrs + slot + 1,
		sizeof(u64) * (nritems - slot - 1));
		}
		node->header.nritems--;
		if (node->header.nritems != 0) {
		int tslot;
		if (slot == 0)
		fixup_low_keys(path, node->keys, level + 1);
		tslot = path->slots[level+1];
		push_node_left(root, path, level);
		if (node->header.nritems) {
		push_node_right(root, path, level);
		}
		path->slots[level+1] = tslot;
		if (node->header.nritems)
		break;
		}
		if (node == root->node) {
		printf("root is now null!\n");
		root->node = NULL;
		break;
		}
		level++;
		if (!path->nodes[level])
		BUG();
		free(node);
		}
		return 0;
		}

		int del_item(struct ctree_root root, struct key key)
		{
		int ret;
		int slot;
		struct leaf *leaf;
		struct ctree_path path;
		int doff;
		int dsize;

		init_path(&path);
		ret = search_slot(root, key, &path);
		if (ret != 0)
		return -1;

		leaf = (struct leaf *)path.nodes[0];
		slot = path.slots[0];
		doff = leaf->items[slot].offset;
		dsize = leaf->items[slot].size;

		if (slot != leaf->header.nritems - 1) {
		int i;
		int data_end = leaf_data_end(leaf);
		memmove(leaf->data + data_end + dsize,
		leaf->data + data_end,
		doff - data_end);
		for (i = slot + 1; i < leaf->header.nritems; i++)
		leaf->items[i].offset += dsize;
		memmove(leaf->items + slot, leaf->items + slot + 1,
		sizeof(struct item) *
		(leaf->header.nritems - slot - 1));
		}
		leaf->header.nritems -= 1;
		if (leaf->header.nritems == 0) {
		free(leaf);
		del_ptr(root, &path, 1);
		} else {
		if (slot == 0)
		fixup_low_keys(&path, &leaf->items[0].key, 1);
		if (leaf_space_used(leaf, 0, leaf->header.nritems) <
		LEAF_DATA_SIZE / 4) {
		/* 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];
		push_leaf_left(root, &path, 1);
		path.slots[1] = slot;
		if (leaf->header.nritems == 0) {
		free(leaf);
		del_ptr(root, &path, 1);
		}
		}
		}
		return 0;
		}

		void print_leaf(struct leaf *l)
		{
		int i;
		int nr = l->header.nritems;
		struct item *item;
		printf("leaf %p total ptrs %d free space %d\n", l, nr,
		leaf_free_space(l));
		fflush(stdout);
		for (i = 0 ; i < nr ; i++) {
		item = l->items + i;
		printf("\titem %d key (%lu %u %lu) itemoff %d itemsize %d\n",
		i,
		item->key.objectid, item->key.flags, item->key.offset,
		item->offset, item->size);
		fflush(stdout);
		printf("\t\titem data %.*s\n", item->size, l->data+item->offset);
		fflush(stdout);
		}
		}
		void print_tree(struct node *c)
		{
		int i;
		int nr;

		if (!c)
		return;
		nr = c->header.nritems;
		if (is_leaf(c->header.flags)) {
		print_leaf((struct leaf *)c);
		return;
		}
		printf("node %p level %d total ptrs %d free spc %lu\n", c,
		node_level(c->header.flags), c->header.nritems,
		NODEPTRS_PER_BLOCK - c->header.nritems);
		fflush(stdout);
		for (i = 0; i < nr; i++) {
		printf("\tkey %d (%lu %u %lu) block %lx\n",
		i,
		c->keys[i].objectid, c->keys[i].flags, c->keys[i].offset,
		c->blockptrs[i]);
		fflush(stdout);
		}
		for (i = 0; i < nr; i++) {
		struct node *next = read_block(c->blockptrs[i]);
		if (is_leaf(next->header.flags) &&
		node_level(c->header.flags) != 1)
		BUG();
		if (node_level(next->header.flags) !=
		node_level(c->header.flags) - 1)
		BUG();
		print_tree(next);
		}

		}

		/* for testing only */
		int next_key(int i, int max_key) {
		return rand() % max_key;
		// return i;
		}

		int main() {
		struct leaf *first_node = malloc(sizeof(struct leaf));
		struct ctree_root root;
		struct key ins;
		char *buf;
		int i;
		int num;
		int ret;
		int run_size = 10000000;
		int max_key = 100000000;
		int tree_size = 0;
		struct ctree_path path;


		srand(55);
		root.node = (struct node *)first_node;
		memset(first_node, 0, sizeof(*first_node));
		for (i = 0; i < run_size; i++) {
		buf = malloc(64);
		num = next_key(i, max_key);
		// num = i;
		sprintf(buf, "string-%d", num);
		// printf("insert %d\n", num);
		ins.objectid = num;
		ins.offset = 0;
		ins.flags = 0;
		ret = insert_item(&root, &ins, buf, strlen(buf));
		if (!ret)
		tree_size++;
		}
		srand(55);
		for (i = 0; i < run_size; i++) {
		num = next_key(i, max_key);
		ins.objectid = num;
		ins.offset = 0;
		ins.flags = 0;
		init_path(&path);
		ret = search_slot(&root, &ins, &path);
		if (ret) {
		print_tree(root.node);
		printf("unable to find %d\n", num);
		exit(1);
		}
		}
		printf("node %p level %d total ptrs %d free spc %lu\n", root.node,
		node_level(root.node->header.flags), root.node->header.nritems,
		NODEPTRS_PER_BLOCK - root.node->header.nritems);
		// print_tree(root.node);
		printf("all searches good\n");
		i = 0;
		srand(55);
		for (i = 0; i < run_size; i++) {
		num = next_key(i, max_key);
		ins.objectid = num;
		del_item(&root, &ins);
		}
		print_tree(root.node);
		return 0;
		}