Btrfs: early extent mapping support

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2007-02-20 16:40:44 -05:00 коммит произвёл David Woodhouse
Родитель 74123bd72a
Коммит d97e63b69e
5 изменённых файлов: 236 добавлений и 33 удалений

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@ -4,8 +4,8 @@ CFLAGS= -g -Wall
.c.o:
$(CC) $(CFLAGS) -c $<
ctree: ctree.o disk-io.h ctree.h disk-io.o radix-tree.o radix-tree.h
gcc $(CFLAGS) -o ctree ctree.o disk-io.o radix-tree.o
ctree: ctree.o disk-io.h ctree.h disk-io.o radix-tree.o radix-tree.h mkfs.o
gcc $(CFLAGS) -o ctree ctree.o disk-io.o radix-tree.o mkfs.o
clean:
rm ctree *.o

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@ -5,6 +5,8 @@
#include "ctree.h"
#include "disk-io.h"
static int refill_alloc_extent(struct ctree_root *root);
static inline void init_path(struct ctree_path *p)
{
memset(p, 0, sizeof(*p));
@ -29,7 +31,7 @@ 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 sizeof(leaf->data);
return leaf->items[nr-1].offset;
}
@ -421,7 +423,7 @@ int insert_ptr(struct ctree_root *root,
* 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, ARRAY_SIZE(bal));
memset(bal, 0, sizeof(bal));
while(t && t->node.header.nritems == NODEPTRS_PER_BLOCK) {
c = &t->node;
if (push_node_left(root, path,
@ -756,6 +758,7 @@ int insert_item(struct ctree_root *root, struct key *key,
if (leaf_free_space(leaf) < 0)
BUG();
release_path(root, &path);
refill_alloc_extent(root);
return 0;
}
@ -884,6 +887,135 @@ int del_item(struct ctree_root *root, struct ctree_path *path)
return 0;
}
int next_leaf(struct ctree_root *root, struct ctree_path *path)
{
int slot;
int level = 1;
u64 blocknr;
struct tree_buffer *c;
struct tree_buffer *next;
while(level < MAX_LEVEL) {
if (!path->nodes[level])
return -1;
slot = path->slots[level] + 1;
c = path->nodes[level];
if (slot >= c->node.header.nritems) {
level++;
continue;
}
blocknr = c->node.blockptrs[slot];
next = read_tree_block(root, blocknr);
break;
}
path->slots[level] = slot;
while(1) {
level--;
c = path->nodes[level];
tree_block_release(root, c);
path->nodes[level] = next;
path->slots[level] = 0;
if (!level)
break;
next = read_tree_block(root, next->node.blockptrs[0]);
}
return 0;
}
int alloc_extent(struct ctree_root *root, u64 num_blocks, u64 search_start,
u64 search_end, u64 owner, struct key *ins)
{
struct ctree_path path;
struct key *key;
int ret;
u64 hole_size = 0;
int slot = 0;
u64 last_block;
int start_found = 0;
struct leaf *l;
struct extent_item extent_item;
init_path(&path);
ins->objectid = search_start;
ins->offset = 0;
ins->flags = 0;
ret = search_slot(root, ins, &path);
while (1) {
l = &path.nodes[0]->leaf;
slot = path.slots[0];
if (!l) {
// FIXME allocate root
}
if (slot >= l->header.nritems) {
ret = next_leaf(root, &path);
if (ret == 0)
continue;
if (!start_found) {
ins->objectid = search_start;
ins->offset = num_blocks;
hole_size = search_end - search_start;
goto insert;
}
ins->objectid = last_block;
ins->offset = num_blocks;
hole_size = search_end - last_block;
goto insert;
}
key = &l->items[slot].key;
if (start_found) {
hole_size = key->objectid - last_block;
if (hole_size > num_blocks) {
ins->objectid = last_block;
ins->offset = num_blocks;
goto insert;
}
} else
start_found = 1;
last_block = key->objectid + key->offset;
path.slots[0]++;
printf("last block is not %lu\n", last_block);
}
// FIXME -ENOSPC
insert:
extent_item.refs = 1;
extent_item.owner = owner;
ret = insert_item(root, ins, &extent_item, sizeof(extent_item));
return ret;
}
static int refill_alloc_extent(struct ctree_root *root)
{
struct alloc_extent *ae = root->alloc_extent;
struct key key;
int ret;
int min_blocks = MAX_LEVEL * 2;
printf("refill alloc root %p, numused %lu total %lu\n", root, ae->num_used, ae->num_blocks);
if (ae->num_blocks > ae->num_used && ae->num_blocks - ae->num_used >
min_blocks)
return 0;
ae = root->reserve_extent;
if (ae->num_blocks > ae->num_used) {
if (root->alloc_extent->num_blocks == 0) {
/* we should swap reserve/alloc_extent when alloc
* fills up
*/
BUG();
}
if (ae->num_blocks - ae->num_used < min_blocks)
BUG();
return 0;
}
// FIXME, this recurses
ret = alloc_extent(root->extent_root,
min_blocks * 2, 0, (unsigned long)-1, 0, &key);
ae->blocknr = key.objectid;
ae->num_blocks = key.offset;
ae->num_used = 0;
return ret;
}
void print_leaf(struct leaf *l)
{
int i;
@ -948,8 +1080,8 @@ 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() {
@ -960,7 +1092,7 @@ int main() {
int i;
int num;
int ret;
int run_size = 25000;
int run_size = 256;
int max_key = 100000000;
int tree_size = 0;
struct ctree_path path;
@ -980,10 +1112,20 @@ int main() {
ins.objectid = num;
ins.offset = 0;
ins.flags = 0;
printf("insert %d\n", i);
ret = insert_item(root, &ins, buf, strlen(buf));
if (!ret)
tree_size++;
printf("done insert %d\n", i);
}
printf("root used: %lu\n", root->alloc_extent->num_used);
printf("root tree\n");
print_tree(root, root->node);
printf("map tree\n");
printf("map used: %lu\n", root->extent_root->alloc_extent->num_used);
print_tree(root->extent_root, root->extent_root->node);
exit(1);
close_ctree(root);
root = open_ctree("dbfile");
printf("starting search\n");

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@ -1,7 +1,7 @@
#ifndef __CTREE__
#define __CTREE__
#define CTREE_BLOCKSIZE 4096
#define CTREE_BLOCKSIZE 256
struct key {
u64 objectid;
@ -22,18 +22,41 @@ struct header {
#define NODEPTRS_PER_BLOCK ((CTREE_BLOCKSIZE - sizeof(struct header)) / \
(sizeof(struct key) + sizeof(u64)))
#define LEVEL_BITS 3
#define MAX_LEVEL (1 << LEVEL_BITS)
#define MAX_LEVEL 8
#define node_level(f) ((f) & (MAX_LEVEL-1))
#define is_leaf(f) (node_level(f) == 0)
struct tree_buffer;
struct alloc_extent {
u64 blocknr;
u64 num_blocks;
u64 num_used;
} __attribute__ ((__packed__));
struct ctree_root {
struct tree_buffer *node;
struct ctree_root *extent_root;
struct alloc_extent *alloc_extent;
struct alloc_extent *reserve_extent;
int fp;
struct radix_tree_root cache_radix;
struct alloc_extent ai1;
struct alloc_extent ai2;
};
struct ctree_root_info {
u64 fsid[2]; /* FS specific uuid */
u64 blocknr; /* blocknr of this block */
u64 objectid; /* inode number of this root */
u64 tree_root; /* the tree root */
u32 csum;
u32 ham;
struct alloc_extent alloc_extent;
struct alloc_extent reserve_extent;
u64 snapuuid[2]; /* root specific uuid */
} __attribute__ ((__packed__));
struct item {
struct key key;
u16 offset;
@ -55,6 +78,11 @@ struct node {
u64 blockptrs[NODEPTRS_PER_BLOCK];
} __attribute__ ((__packed__));
struct extent_item {
u32 refs;
u64 owner;
} __attribute__ ((__packed__));
struct ctree_path {
struct tree_buffer *nodes[MAX_LEVEL];
int slots[MAX_LEVEL];

Просмотреть файл

@ -12,25 +12,27 @@
static int allocated_blocks = 0;
struct ctree_header {
u64 root_block;
} __attribute__ ((__packed__));
static int get_free_block(struct ctree_root *root, u64 *block)
{
struct stat st;
int ret;
if (root->alloc_extent->num_used >= root->alloc_extent->num_blocks)
return -1;
*block = root->alloc_extent->blocknr + root->alloc_extent->num_used;
root->alloc_extent->num_used += 1;
if (root->alloc_extent->num_used >= root->alloc_extent->num_blocks) {
struct alloc_extent *ae = root->alloc_extent;
root->alloc_extent = root->reserve_extent;
root->reserve_extent = ae;
ae->num_blocks = 0;
}
st.st_size = 0;
ret = fstat(root->fp, &st);
if (st.st_size > sizeof(struct ctree_header)) {
*block = (st.st_size -
sizeof(struct ctree_header)) / CTREE_BLOCKSIZE;
} else {
*block = 0;
}
ret = ftruncate(root->fp, sizeof(struct ctree_header) + (*block + 1) *
CTREE_BLOCKSIZE);
if (st.st_size < (*block + 1) * CTREE_BLOCKSIZE)
ret = ftruncate(root->fp,
(*block + 1) * CTREE_BLOCKSIZE);
return ret;
}
@ -72,7 +74,7 @@ struct tree_buffer *alloc_free_block(struct ctree_root *root)
struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr)
{
loff_t offset = blocknr * CTREE_BLOCKSIZE + sizeof(struct ctree_header);
loff_t offset = blocknr * CTREE_BLOCKSIZE;
struct tree_buffer *buf;
int ret;
@ -101,7 +103,7 @@ struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr)
int write_tree_block(struct ctree_root *root, struct tree_buffer *buf)
{
u64 blocknr = buf->blocknr;
loff_t offset = blocknr * CTREE_BLOCKSIZE + sizeof(struct ctree_header);
loff_t offset = blocknr * CTREE_BLOCKSIZE;
int ret;
if (buf->blocknr != buf->node.header.blocknr)
@ -114,11 +116,32 @@ int write_tree_block(struct ctree_root *root, struct tree_buffer *buf)
return 0;
}
struct ctree_super_block {
struct ctree_root_info root_info;
struct ctree_root_info extent_info;
} __attribute__ ((__packed__));
static int __setup_root(struct ctree_root *root, struct ctree_root *extent_root,
struct ctree_root_info *info, int fp)
{
root->fp = fp;
root->node = read_tree_block(root, info->tree_root);
root->extent_root = extent_root;
memcpy(&root->ai1, &info->alloc_extent, sizeof(info->alloc_extent));
memcpy(&root->ai2, &info->reserve_extent, sizeof(info->reserve_extent));
root->alloc_extent = &root->ai1;
root->reserve_extent = &root->ai2;
INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL);
printf("setup done reading root %p, used %lu\n", root, root->alloc_extent->num_used);
return 0;
}
struct ctree_root *open_ctree(char *filename)
{
struct ctree_root *root = malloc(sizeof(struct ctree_root));
struct ctree_root *extent_root = malloc(sizeof(struct ctree_root));
struct ctree_super_block super;
int fp;
u64 root_block;
int ret;
fp = open(filename, O_CREAT | O_RDWR);
@ -126,14 +149,20 @@ struct ctree_root *open_ctree(char *filename)
free(root);
return NULL;
}
root->fp = fp;
INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL);
ret = pread(fp, &root_block, sizeof(u64), 0);
if (ret == sizeof(u64)) {
printf("reading root node at block %lu\n", root_block);
root->node = read_tree_block(root, root_block);
} else
root->node = NULL;
ret = pread(fp, &super, sizeof(struct ctree_super_block),
CTREE_SUPER_INFO_OFFSET(CTREE_BLOCKSIZE));
if (ret == 0) {
ret = mkfs(fp);
if (ret)
return NULL;
ret = pread(fp, &super, sizeof(struct ctree_super_block),
CTREE_SUPER_INFO_OFFSET(CTREE_BLOCKSIZE));
if (ret != sizeof(struct ctree_super_block))
return NULL;
}
BUG_ON(ret < 0);
__setup_root(root, extent_root, &super.root_info, fp);
__setup_root(extent_root, extent_root, &super.extent_info, fp);
return root;
}
@ -160,6 +189,7 @@ int update_root_block(struct ctree_root *root)
void tree_block_release(struct ctree_root *root, struct tree_buffer *buf)
{
return;
buf->count--;
if (buf->count == 0) {
if (!radix_tree_lookup(&root->cache_radix, buf->blocknr))

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@ -17,5 +17,8 @@ int close_ctree(struct ctree_root *root);
void tree_block_release(struct ctree_root *root, struct tree_buffer *buf);
struct tree_buffer *alloc_free_block(struct ctree_root *root);
int update_root_block(struct ctree_root *root);
int mkfs(int fd);
#define CTREE_SUPER_INFO_OFFSET(bs) (16 * (bs))
#endif