Re: [PATCH 2/7] btrfs: add workspace manager initialization for zstd

[David Sterba <dsterba@suse.cz>]

On Thu, Aug 14, 2025 at 03:03:21PM +0930, Qu Wenruo wrote:
> This involves:
> 
> - Add zstd_alloc_workspace_manager() and zstd_free_workspace_manager()
>   Those two functions will accept an fs_info pointer, and alloc/free
>   fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD] pointer.
> 
> - Add btrfs_alloc_compress_wsm() and btrfs_free_compress_wsm()
>   Those are helpers allocating the workspace managers for all
>   algorithms.
>   For now only zstd is supported, and the timing is a little unusual,
>   the btrfs_alloc_compress_wsm() should only be called after the
>   sectorsize being initialized.
> 
>   Meanwhile btrfs_free_fs_info_compress() is called in
>   btrfs_free_fs_info().
> 
> - Move the definition of btrfs_compression_type to "fs.h"
>   The reason is that "compression.h" has already included "fs.h", thus
>   we can not just include "compression.h" to get the definition of
>   BTRFS_NR_COMPRESS_TYPES to define fs_info::compr_wsm[].

This is a bit unfortunate, I'd like to keep the subystems in their own
files but we'd have to add another kind of indirection to resolve that.
Either a new header or another structure for the compression types that
is not embedded in fs_info. But the type definitions are short and used
in a lot of code anyway so no big deal.