Re: [PATCH v3 1/3] ocfs2: give ocfs2 the ability to reclaim suballoc free bg

[Heming Zhao]

On 9/8/24 22:07, Heming Zhao wrote:
> The current ocfs2 code can't reclaim suballocator block group space.
> This cause ocfs2 to hold onto a lot of space in some cases. for example,
> when creating lots of small files, the space is held/managed by
> '//inode_alloc'. After the user deletes all the small files, the space
> never returns to '//global_bitmap'. This issue prevents ocfs2 from
> providing the needed space even when there is enough free space in a
> small ocfs2 volume.
> This patch gives ocfs2 the ability to reclaim suballoc free space when
> the block group is freed. For performance reasons, this patch keeps
> the first suballocator block group.
>
> Signed-off-by: Heming Zhao <heming.zhao@xxxxxxxx>
> Reviewed-by: Su Yue <glass.su@xxxxxxxx>
> ---
>   fs/ocfs2/suballoc.c | 302 ++++++++++++++++++++++++++++++++++++++++++--
>   1 file changed, 292 insertions(+), 10 deletions(-)
>
> diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
> index f7b483f0de2a..d62010166c34 100644
> --- a/fs/ocfs2/suballoc.c
> +++ b/fs/ocfs2/suballoc.c
> ... ...
>   
> +/*
> + * Reclaim the suballocator managed space to main bitmap.
> + * This function first works on the suballocator then switch to the
> + * main bitmap.

need to revise above comment:
This function first works on the suballocator to perform the
cleanup rec/alloc_inode job, then switches to the main bitmap
to reclaim released space.

-Heming

> + *
> + * handle: The transaction handle
> + * alloc_inode: The suballoc inode
> + * alloc_bh: The buffer_head of suballoc inode
> + * group_bh: The group descriptor buffer_head of suballocator managed.
> + *           Caller should release the input group_bh.
> + */
> +static int _reclaim_to_main_bm(handle_t *handle,
> +			struct inode *alloc_inode,
> +			struct buffer_head *alloc_bh,
> +			struct buffer_head *group_bh)
> +{