On 2017年12月20日 16:21, Su Yue wrote:
>
>
> On 12/20/2017 01:41 PM, Qu Wenruo wrote:
>>
>>
>> On 2017年12月20日 12:57, Su Yue wrote:
>>> Introduce create_chunk_and_block_block_group() to allocate new chunk
>>> and corresponding block group.
>>>
>>> The new function force_cow_in_new_chunk() first allocates new chunk
>>> and records its start.
>>> Then it modifies all metadata block groups cached and full.
>>> Finally it marks the new block group uncached and unfree.
>>> In the next CoW, extents states will be updated automatically by
>>> cache_block_group().
>>>
>>> Suggested-by: Qu Wenruo <wqu@xxxxxxxx>
>>> Signed-off-by: Su Yue <suy.fnst@xxxxxxxxxxxxxx>
>>> ---
>>> cmds-check.c | 80
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> 1 file changed, 80 insertions(+)
>>>
>>> diff --git a/cmds-check.c b/cmds-check.c
>>> index d98d4bda7357..311c8a9f45e8 100644
>>> --- a/cmds-check.c
>>> +++ b/cmds-check.c
>>> @@ -10911,6 +10911,86 @@ out:
>>> return ret;
>>> }
>>> +static int create_chunk_and_block_group(struct btrfs_fs_info
>>> *fs_info,
>>> + u64 flags, u64 *start, u64 *nbytes)
>>> +{
>>> + struct btrfs_trans_handle *trans;
>>> + struct btrfs_root *root = fs_info->extent_root;
>>> + int ret;
>>> +
>>> + if ((flags & BTRFS_BLOCK_GROUP_TYPE_MASK) == 0)
>>> + return -EINVAL;
>>> +
>>> + trans = btrfs_start_transaction(root, 1);
>>> + if (IS_ERR(trans)) {
>>> + ret = PTR_ERR(trans);
>>> + error("error starting transaction %s", strerror(-ret));
>>> + return ret;
>>> + }
>>> + ret = btrfs_alloc_chunk(trans, fs_info, start, nbytes, flags);
>>> + if (ret) {
>>> + error("fail to allocate new chunk %s", strerror(-ret));
>>> + goto out;
>>> + }
>>> + ret = btrfs_make_block_group(trans, fs_info, 0, flags,
>>> + BTRFS_FIRST_CHUNK_TREE_OBJECTID, *start, *nbytes);
>>> + if (ret) {
>>> + error("fail to make block group for chunk %llu %llu %s",
>>> + *start, *nbytes, strerror(-ret));
>>> + goto out;
>>> + }
>>> +out:
>>> + btrfs_commit_transaction(trans, root);
>>> + return ret;
>>> +}
>>> +
>>> +static int force_cow_in_new_chunk(struct btrfs_fs_info *fs_info)
>>> +{
>>> + struct btrfs_block_group_cache *bg;
>>> + u64 start;
>>> + u64 nbytes;
>>> + u64 alloc_profile;
>>> + u64 flags;
>>> + int ret;
>>> +
>>> + alloc_profile = (fs_info->avail_metadata_alloc_bits &
>>> + fs_info->metadata_alloc_profile);
>>> + flags = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
>>> + if (btrfs_fs_incompat(fs_info, MIXED_GROUPS))
>>> + flags |= BTRFS_BLOCK_GROUP_DATA;
>>> +
>>> + ret = create_chunk_and_block_group(fs_info, flags, &start,
>>> &nbytes);
>>
>> Why bother allocating a new chunk by yourself?
>>
>> Just mark all block groups full and that's all.
>>
>> Any later tree block allocation like btrfs_search_slot() with @cow = 1
>> will trigger chunk allocation automatically.
>>
>
> Tried to let it happen but BUG_ON with -ENOSPC.
Then fix it.
It's not a normal behavior in this case.
Thanks,
Qu
> Do you mean do_chunk_alloc() in btrfs_reserve_extent() which is called
> while doing CoW?> In progs, allocation of new chunk during CoW depends @root->ref_cows.
> However, @root->ref_cows should be set only if @root is root of a fs
> trees.
>
> Thanks,
> Su
>
>> Thanks,
>> Qu
>>
>>> + if (!ret)
>>> + printf("Create new chunk %llu %llu\n", start, nbytes);
>>> + else
>>> + goto err;
>>> +
>>> + flags = BTRFS_BLOCK_GROUP_METADATA;
>>> + /* Mark all metadata block groups cached and full in free space*/
>>> + ret = modify_block_groups_cache(fs_info, flags, 1);
>>> + if (ret)
>>> + goto clear_bg_cache;
>>> +
>>> + bg = btrfs_lookup_block_group(fs_info, start);
>>> + if (!bg) {
>>> + ret = -ENOENT;
>>> + error("fail to look up block group %llu %llu", start, nbytes);
>>> + goto clear_bg_cache;
>>> + }
>>> +
>>> + /* Clear block group cache just allocated */
>>> + ret = modify_block_group_cache(fs_info, bg, 0);
>>> + if (ret)
>>> + goto clear_bg_cache;
>>> +
>>> + return 0;
>>> +
>>> +clear_bg_cache:
>>> + modify_block_groups_cache(fs_info, flags, 0);
>>> +err:
>>> + return ret;
>>> +}
>>> +
>>> static int check_extent_refs(struct btrfs_root *root,
>>> struct cache_tree *extent_cache)
>>> {
>>>
>>
>
>
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