Btrfs: early extent mapping support
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 8d51a07..653f18aa 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -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 *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 @@
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 @@
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 @@
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 @@
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))
