Re: [PATCH 10/11] xfs: refactor xfs_icache_free_{eof,cow}blocks call sites

[Brian Foster <bfoster@redhat.com>]

On Sat, Jan 23, 2021 at 10:52:55AM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> In anticipation of more restructuring of the eof/cowblocks gc code,
> refactor calling of those two functions into a single internal helper
> function, then present a new standard interface to purge speculative
> block preallocations and start shifting higher level code to use that.
> 
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  fs/xfs/xfs_file.c   |    3 +--
>  fs/xfs/xfs_icache.c |   39 +++++++++++++++++++++++++++++++++------
>  fs/xfs/xfs_icache.h |    1 +
>  fs/xfs/xfs_trace.h  |    1 +
>  4 files changed, 36 insertions(+), 8 deletions(-)
> 
> 
...
> diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> index 7f999f9dd80a..0d228a5e879f 100644
> --- a/fs/xfs/xfs_icache.c
> +++ b/fs/xfs/xfs_icache.c
> @@ -1645,6 +1645,38 @@ xfs_start_block_reaping(
>  	xfs_queue_cowblocks(mp);
>  }
>  
> +/* Scan all incore inodes for block preallocations that we can remove. */
> +static inline int
> +xfs_blockgc_scan(
> +	struct xfs_mount	*mp,
> +	struct xfs_eofblocks	*eofb)
> +{
> +	int			error;
> +
> +	error = xfs_icache_free_eofblocks(mp, eofb);
> +	if (error)
> +		return error;
> +
> +	error = xfs_icache_free_cowblocks(mp, eofb);
> +	if (error)
> +		return error;
> +
> +	return 0;
> +}
> +
> +/*
> + * Try to free space in the filesystem by purging eofblocks and cowblocks.
> + */
> +int
> +xfs_blockgc_free_space(
> +	struct xfs_mount	*mp,
> +	struct xfs_eofblocks	*eofb)
> +{
> +	trace_xfs_blockgc_free_space(mp, eofb, _RET_IP_);
> +
> +	return xfs_blockgc_scan(mp, eofb);
> +}
> +

What's the need for two helpers instead of just
xfs_blockgc_free_space()? Otherwise seems fine.

Brian

>  /*
>   * Run cow/eofblocks scans on the supplied dquots.  We don't know exactly which
>   * quota caused an allocation failure, so we make a best effort by including
> @@ -1661,7 +1693,6 @@ xfs_blockgc_free_dquots(
>  	struct xfs_eofblocks	eofb = {0};
>  	struct xfs_mount	*mp = NULL;
>  	bool			do_work = false;
> -	int			error;
>  
>  	if (!udqp && !gdqp && !pdqp)
>  		return 0;
> @@ -1699,11 +1730,7 @@ xfs_blockgc_free_dquots(
>  	if (!do_work)
>  		return 0;
>  
> -	error = xfs_icache_free_eofblocks(mp, &eofb);
> -	if (error)
> -		return error;
> -
> -	return xfs_icache_free_cowblocks(mp, &eofb);
> +	return xfs_blockgc_free_space(mp, &eofb);
>  }
>  
>  /*
> diff --git a/fs/xfs/xfs_icache.h b/fs/xfs/xfs_icache.h
> index 5f520de637f6..583c132ae0fb 100644
> --- a/fs/xfs/xfs_icache.h
> +++ b/fs/xfs/xfs_icache.h
> @@ -57,6 +57,7 @@ void xfs_inode_set_reclaim_tag(struct xfs_inode *ip);
>  int xfs_blockgc_free_dquots(struct xfs_dquot *udqp, struct xfs_dquot *gdqp,
>  		struct xfs_dquot *pdqp, unsigned int eof_flags);
>  int xfs_blockgc_free_quota(struct xfs_inode *ip, unsigned int eof_flags);
> +int xfs_blockgc_free_space(struct xfs_mount *mp, struct xfs_eofblocks *eofb);
>  
>  void xfs_inode_set_eofblocks_tag(struct xfs_inode *ip);
>  void xfs_inode_clear_eofblocks_tag(struct xfs_inode *ip);
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 4cbf446bae9a..c3fd344aaf5b 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -3926,6 +3926,7 @@ DEFINE_EVENT(xfs_eofblocks_class, name,	\
>  		 unsigned long caller_ip), \
>  	TP_ARGS(mp, eofb, caller_ip))
>  DEFINE_EOFBLOCKS_EVENT(xfs_ioc_free_eofblocks);
> +DEFINE_EOFBLOCKS_EVENT(xfs_blockgc_free_space);
>  
>  #endif /* _TRACE_XFS_H */
>  
>