/*
* Find a free inode index for later btrfs_add_link().
* Currently just search from the largest dir_index and +1.
*/
static int btrfs_find_free_dir_index(struct btrfs_root *root, u64 dir_ino,
u64 *ret_ino)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_key found_key;
u64 ret_val = 2;
int ret = 0;
if (!ret_ino)
return 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = dir_ino;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
ret = 0;
if (path->slots[0] == 0) {
ret = btrfs_prev_leaf(root, path);
if (ret < 0)
goto out;
if (ret > 0) {
/*
* This shouldn't happen since there must be a leaf
* containing the DIR_ITEM.
* Can only happen when the previous leaf is corrupted.
*/
ret = -EIO;
goto out;
}
} else {
path->slots[0]--;
}
btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
if (found_key.objectid != dir_ino ||
found_key.type != BTRFS_DIR_INDEX_KEY)
goto out;
ret_val = found_key.offset + 1;
out:
btrfs_free_path(path);
if (ret == 0)
*ret_ino = ret_val;
return ret;
}
/*
* Get the first file extent that covers (part of) the given range
* Unlike kernel using extent_map to handle hole even no-hole is enabled,
* progs don't have such infrastructure, so caller should do extra care
* for no-hole.
*
* return 0 for found, and path points to the file extent.
* return >0 for not found, and path points to the insert position.
* return <0 for error.
*/
int btrfs_get_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
u64 ino, u64 offset, u64 len, int ins_len)
{
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_file_extent_item *fi_item;
u64 end = 0;
int ret = 0;
int not_found = 1;
key.objectid = ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = offset;
ret = btrfs_search_slot(trans, root, &key, path, ins_len,
ins_len ? 1 : 0);
if (ret <= 0)
goto out;
if (ret > 0) {
/* Check preivous file extent */
ret = btrfs_previous_item(root, path, ino,
BTRFS_EXTENT_DATA_KEY);
if (ret < 0)
goto out;
if (ret > 0)
goto check_next;
}
btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
if (found_key.objectid != ino ||
found_key.type != BTRFS_EXTENT_DATA_KEY)
goto check_next;
fi_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_file_extent_item);
end = found_key.offset +
btrfs_file_extent_ram_bytes(path->nodes[0], fi_item);
/*
* existing file extent
* |--------| |----|
* |-------|
* offset + len
* OR
* |---------------|
* |-------|
*/
if (end > offset) {
not_found = 0;
goto out;
}
check_next:
ret = btrfs_next_item(root, path);
if (ret)
goto out;
btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
if (found_key.objectid != ino ||
found_key.type != BTRFS_EXTENT_DATA_KEY) {
ret = 1;
goto out;
}
if (found_key.offset < offset + len)
/*
* existing file extent
* |---| |------|
* |-------|
* offset + len
*/
not_found = 0;
else
/*
* existing file extent
* |----| |----|
* |----|
* offset + len
*/
not_found = 1;
/*
* To keep the search hehavior consistent with search_slot(),
* we need to go back to the prev leaf's nritem slot if
* we are at the first slot of the leaf.
*/
if (path->slots[0] == 0) {
ret = btrfs_prev_leaf(root, path);
/* Not possible */
if (ret)
goto out;
path->slots[0] = btrfs_header_nritems(path->nodes[0]);
}
out:
if (ret == 0)
ret = not_found;
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;
while (1) {
u32 nritems;
if (path->slots[0] == 0) {
btrfs_set_path_blocking(path);
ret = btrfs_prev_leaf(fs_info->extent_root, path);
if (ret != 0) {
if (ret > 0) {
pr_debug("logical %llu is not within "
"any extent\n", logical);
ret = -ENOENT;
}
return ret;
}
} else {
path->slots[0]--;
}
nritems = btrfs_header_nritems(path->nodes[0]);
if (nritems == 0) {
pr_debug("logical %llu is not within any extent\n",
logical);
return -ENOENT;
}
if (path->slots[0] == nritems)
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], found_key,
path->slots[0]);
if (found_key->type == BTRFS_EXTENT_ITEM_KEY ||
found_key->type == BTRFS_METADATA_ITEM_KEY)
break;
}
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;
}
