Re: [PATCH v2 06/18] xfs: Factor out new helper functions xfs_attr_rmtval_set

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Fri, Aug 09, 2019 at 02:37:14PM -0700, Allison Collins wrote:
> Break xfs_attr_rmtval_set into two helper functions
> xfs_attr_rmt_find_hole and xfs_attr_rmtval_set_value.
> xfs_attr_rmtval_set rolls the transaction between the
> helpers, but delayed operations cannot.  We will use
> the helpers later when constructing new delayed
> attribute routines.
> 
> Signed-off-by: Allison Collins <allison.henderson@oracle.com>
> ---
>  fs/xfs/libxfs/xfs_attr_remote.c | 73 +++++++++++++++++++++++++++++++----------
>  fs/xfs/libxfs/xfs_attr_remote.h |  4 ++-
>  2 files changed, 58 insertions(+), 19 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr_remote.c b/fs/xfs/libxfs/xfs_attr_remote.c
> index 4eb30d3..c421412 100644
> --- a/fs/xfs/libxfs/xfs_attr_remote.c
> +++ b/fs/xfs/libxfs/xfs_attr_remote.c
> @@ -21,6 +21,7 @@
>  #include "xfs_attr.h"
>  #include "xfs_trace.h"
>  #include "xfs_error.h"
> +#include "xfs_attr_remote.h"
>  
>  #define ATTR_RMTVALUE_MAPSIZE	1	/* # of map entries at once */
>  
> @@ -430,34 +431,18 @@ xfs_attr_rmtval_set(
>  	struct xfs_da_args	*args)
>  {
>  	struct xfs_inode	*dp = args->dp;
> -	struct xfs_mount	*mp = dp->i_mount;
>  	struct xfs_bmbt_irec	map;
>  	xfs_dablk_t		lblkno;
>  	xfs_fileoff_t		lfileoff = 0;
> -	uint8_t			*src = args->value;
>  	int			blkcnt;
> -	int			valuelen;
>  	int			nmap;
>  	int			error;
> -	int			offset = 0;
>  
> -	trace_xfs_attr_rmtval_set(args);
> -
> -	/*
> -	 * Find a "hole" in the attribute address space large enough for
> -	 * us to drop the new attribute's value into. Because CRC enable
> -	 * attributes have headers, we can't just do a straight byte to FSB
> -	 * conversion and have to take the header space into account.
> -	 */
> -	blkcnt = xfs_attr3_rmt_blocks(mp, args->rmtvaluelen);
> -	error = xfs_bmap_first_unused(args->trans, args->dp, blkcnt, &lfileoff,
> -						   XFS_ATTR_FORK);
> +	error = xfs_attr_rmt_find_hole(args, &blkcnt, &lfileoff);
>  	if (error)
>  		return error;
>  
> -	args->rmtblkno = lblkno = (xfs_dablk_t)lfileoff;
> -	args->rmtblkcnt = blkcnt;
> -
> +	lblkno = (xfs_dablk_t)lfileoff;
>  	/*
>  	 * Roll through the "value", allocating blocks on disk as required.
>  	 */
> @@ -498,6 +483,58 @@ xfs_attr_rmtval_set(
>  			return error;
>  	}
>  
> +	error = xfs_attr_rmtval_set_value(args);
> +	return error;
> +}
> +
> +
> +

Only need one blank line between functions.

> +int
> +xfs_attr_rmt_find_hole(
> +	struct xfs_da_args	*args,
> +	int			*blkcnt,
> +	xfs_fileoff_t		*lfileoff)
> +{
> +	struct xfs_inode        *dp = args->dp;
> +	struct xfs_mount	*mp = dp->i_mount;
> +	int			error;
> +
> +	trace_xfs_attr_rmtval_set(args);

Shouldn't this be in the xfs_attr_rmtval_set_value function?
We're not actually setting anything here, we're just looking for holes.

> +
> +	/*
> +	 * Find a "hole" in the attribute address space large enough for
> +	 * us to drop the new attribute's value into. Because CRC enable

This first sentence would make a lovely comment above this function
telling us what it does.

> +	 * attributes have headers, we can't just do a straight byte to FSB
> +	 * conversion and have to take the header space into account.
> +	 */
> +	*blkcnt = xfs_attr3_rmt_blocks(mp, args->rmtvaluelen);

Can the callers be refactored to use args->rmtblkcnt to eliminate the
@blkcnt parameter?

--D

> +	error = xfs_bmap_first_unused(args->trans, args->dp, *blkcnt, lfileoff,
> +						   XFS_ATTR_FORK);
> +	if (error)
> +		return error;
> +
> +	args->rmtblkno = (xfs_dablk_t)*lfileoff;
> +	args->rmtblkcnt = *blkcnt;
> +
> +	return 0;
> +}
> +
> +int
> +xfs_attr_rmtval_set_value(
> +	struct xfs_da_args	*args)
> +{
> +	struct xfs_inode	*dp = args->dp;
> +	struct xfs_mount	*mp = dp->i_mount;
> +	struct xfs_bmbt_irec	map;
> +	xfs_dablk_t		lblkno;
> +	uint8_t			*src = args->value;
> +	int			blkcnt;
> +	int			valuelen;
> +	int			nmap;
> +	int			error;
> +	int			offset = 0;
> +
> +
>  	/*
>  	 * Roll through the "value", copying the attribute value to the
>  	 * already-allocated blocks.  Blocks are written synchronously
> diff --git a/fs/xfs/libxfs/xfs_attr_remote.h b/fs/xfs/libxfs/xfs_attr_remote.h
> index 9d20b66..2a73cd9 100644
> --- a/fs/xfs/libxfs/xfs_attr_remote.h
> +++ b/fs/xfs/libxfs/xfs_attr_remote.h
> @@ -11,5 +11,7 @@ int xfs_attr3_rmt_blocks(struct xfs_mount *mp, int attrlen);
>  int xfs_attr_rmtval_get(struct xfs_da_args *args);
>  int xfs_attr_rmtval_set(struct xfs_da_args *args);
>  int xfs_attr_rmtval_remove(struct xfs_da_args *args);
> -
> +int xfs_attr_rmtval_set_value(struct xfs_da_args *args);
> +int xfs_attr_rmt_find_hole(struct xfs_da_args *args, int *blkcnt,
> +			   xfs_fileoff_t *lfileoff);
>  #endif /* __XFS_ATTR_REMOTE_H__ */
> -- 
> 2.7.4
>