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Btrfs: early extent mapping support

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Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2007-02-20 16:40:44 -05:00
committed by David Woodhouse
parent 74123bd72a
commit d97e63b69e
5 changed files with 236 additions and 33 deletions
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76
fs/btrfs/disk-io.c
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@@ -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))