Re: [PATCH 13/19] btrfs: extent-tree: Add new verions of btrfs_check_data_free_space

[Tsutomu Itoh <t-itoh@jp.fujitsu.com>]

Hi, Qu,

On 2015/09/08 18:22, Qu Wenruo wrote:
> Add new function __btrfs_check_data_free_space() to do precious space
> reservation.
> 
> The new function will replace old btrfs_check_data_free_space(), but
> until all the change is done, let's just use the new name.
> 
> Also, export internal use function btrfs_alloc_data_chunk_ondemand(), as
> now qgroup reserve requires precious bytes, which can only be got in
> later loop(like fallocate).
> But data space info check and data chunk allocate doesn't need to be
> that accurate, and can be called at the beginning.
> 
> So export it for later operations.
> 
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
> ---
>   fs/btrfs/ctree.h       |  2 ++
>   fs/btrfs/extent-tree.c | 50 +++++++++++++++++++++++++++++++++++++++++---------
>   2 files changed, 43 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index ae86025..c1a0aaf 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -3453,6 +3453,8 @@ enum btrfs_reserve_flush_enum {
>   };
>   
>   int btrfs_check_data_free_space(struct inode *inode, u64 bytes, u64 write_bytes);
> +int __btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len);
> +int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes);
>   void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes);
>   void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
>   				struct btrfs_root *root);
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 402415c..61366ca 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -3907,11 +3907,7 @@ u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
>   	return ret;
>   }
>   
> -/*
> - * This will check the space that the inode allocates from to make sure we have
> - * enough space for bytes.
> - */
> -int btrfs_check_data_free_space(struct inode *inode, u64 bytes, u64 write_bytes)
> +int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
>   {
>   	struct btrfs_space_info *data_sinfo;
>   	struct btrfs_root *root = BTRFS_I(inode)->root;
> @@ -4032,19 +4028,55 @@ commit_trans:
>   					      data_sinfo->flags, bytes, 1);
>   		return -ENOSPC;
>   	}
> -	ret = btrfs_qgroup_reserve(root, write_bytes);
> -	if (ret)
> -		goto out;
>   	data_sinfo->bytes_may_use += bytes;
>   	trace_btrfs_space_reservation(root->fs_info, "space_info",
>   				      data_sinfo->flags, bytes, 1);
> -out:
>   	spin_unlock(&data_sinfo->lock);
>   
>   	return ret;
>   }
>   
>   /*
> + * This will check the space that the inode allocates from to make sure we have
> + * enough space for bytes.
> + */
> +int btrfs_check_data_free_space(struct inode *inode, u64 bytes, u64 write_bytes)
> +{
> +	struct btrfs_root *root = BTRFS_I(inode)->root;
> +	int ret;
> +
> +	ret = btrfs_alloc_data_chunk_ondemand(inode, bytes);
> +	if (ret < 0)
> +		return ret;
> +	ret = btrfs_qgroup_reserve(root, write_bytes);
> +	return ret;
> +}
> +
> +/*

> + * New check_data_free_space() with ability for precious data reserveation

                                                                 reservation

Thanks,
Tsutomu

> + * Will replace old btrfs_check_data_free_space(), but for patch split,
> + * add a new function first and then replace it.
> + */
> +int __btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
> +{
> +	struct btrfs_root *root = BTRFS_I(inode)->root;
> +	int ret;
> +
> +	/* align the range */
> +	len = round_up(start + len, root->sectorsize) -
> +	      round_down(start, root->sectorsize);
> +	start = round_down(start, root->sectorsize);
> +
> +	ret = btrfs_alloc_data_chunk_ondemand(inode, len);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Use new btrfs_qgroup_reserve_data to reserve precious data space */
> +	ret = btrfs_qgroup_reserve_data(inode, start, len);
> +	return ret;
> +}
> +
> +/*
>    * Called if we need to clear a data reservation for this inode.
>    */
>   void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
>