static int map_one_extent(struct btrfs_fs_info *fs_info,
u64 *logical_ret, u64 *len_ret, int search_forward)
{
struct btrfs_path *path;
struct btrfs_key key;
u64 logical;
u64 len = 0;
int ret = 0;
BUG_ON(!logical_ret);
logical = *logical_ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = logical;
key.type = 0;
key.offset = 0;
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path,
0, 0);
if (ret < 0)
goto out;
BUG_ON(ret == 0);
ret = 0;
again:
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if ((search_forward && key.objectid < logical) ||
(!search_forward && key.objectid > logical) ||
(key.type != BTRFS_EXTENT_ITEM_KEY &&
key.type != BTRFS_METADATA_ITEM_KEY)) {
if (!search_forward)
ret = btrfs_previous_extent_item(fs_info->extent_root,
path, 0);
else
ret = btrfs_next_extent_item(fs_info->extent_root,
path, 0);
if (ret)
goto out;
goto again;
}
logical = key.objectid;
if (key.type == BTRFS_METADATA_ITEM_KEY)
len = fs_info->nodesize;
else
len = key.offset;
out:
btrfs_free_path(path);
if (!ret) {
*logical_ret = logical;
if (len_ret)
*len_ret = len;
}
return ret;
}
/*
* this makes the path point to (logical EXTENT_ITEM *)
* returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
* tree blocks and <0 on error.
*/
int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
struct btrfs_path *path, struct btrfs_key *found_key,
u64 *flags_ret)
{
int ret;
u64 flags;
u64 size = 0;
u32 item_size;
struct extent_buffer *eb;
struct btrfs_extent_item *ei;
struct btrfs_key key;
if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
key.type = BTRFS_METADATA_ITEM_KEY;
else
key.type = BTRFS_EXTENT_ITEM_KEY;
key.objectid = logical;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
if (ret < 0)
return ret;
ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0);
if (ret) {
if (ret > 0)
ret = -ENOENT;
return ret;
}
btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
if (found_key->type == BTRFS_METADATA_ITEM_KEY)
size = fs_info->extent_root->leafsize;
else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
size = found_key->offset;
if (found_key->objectid > logical ||
found_key->objectid + size <= logical) {
pr_debug("logical %llu is not within any extent\n", logical);
return -ENOENT;
}
eb = path->nodes[0];
item_size = btrfs_item_size_nr(eb, path->slots[0]);
BUG_ON(item_size < sizeof(*ei));
ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
flags = btrfs_extent_flags(eb, ei);
pr_debug("logical %llu is at position %llu within the extent (%llu "
"EXTENT_ITEM %llu) flags %#llx size %u\n",
logical, logical - found_key->objectid, found_key->objectid,
found_key->offset, flags, item_size);
WARN_ON(!flags_ret);
if (flags_ret) {
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
*flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
else if (flags & BTRFS_EXTENT_FLAG_DATA)
*flags_ret = BTRFS_EXTENT_FLAG_DATA;
else
BUG_ON(1);
return 0;
}
return -EIO;
}