Re: [PATCH v2 04/18] xfs: Add xfs_attr_set_deferred and xfs_attr_remove_deferred

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

On Fri, Aug 09, 2019 at 02:37:12PM -0700, Allison Collins wrote:
> From: Allison Henderson <allison.henderson@oracle.com>
> 
> These routines set up set and start a new deferred attribute
> operation.  These functions are meant to be called by other
> code needing to initiate a deferred attribute operation.
> 
> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
> Signed-off-by: Allison Collins <allison.henderson@oracle.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++
>  fs/xfs/libxfs/xfs_attr.h |  5 ++++
>  2 files changed, 79 insertions(+)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 1f76618..a2fba0c 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -25,6 +25,7 @@
>  #include "xfs_trans_space.h"
>  #include "xfs_trace.h"
>  #include "xfs_attr_item.h"
> +#include "xfs_attr.h"
>  
>  /*
>   * xfs_attr.c
> @@ -399,6 +400,48 @@ xfs_attr_set(
>  	goto out_unlock;
>  }
>  
> +/* Sets an attribute for an inode as a deferred operation */
> +int
> +xfs_attr_set_deferred(
> +	struct xfs_inode	*dp,
> +	struct xfs_trans	*tp,
> +	struct xfs_name		*name,
> +	const unsigned char	*value,
> +	unsigned int		valuelen)
> +{
> +
> +	struct xfs_attr_item	*new;
> +	char			*name_value;
> +
> +	/*
> +	 * All set operations must have a name but not necessarily a value.
> +	 */
> +	if (!name->len) {
> +		ASSERT(0);
> +		return -EINVAL;
> +	}
> +
> +	new = kmem_alloc_large(XFS_ATTR_ITEM_SIZEOF(name->len, valuelen),
> +			 KM_SLEEP|KM_NOFS);
> +	name_value = ((char *)new) + sizeof(struct xfs_attr_item);
> +	memset(new, 0, XFS_ATTR_ITEM_SIZEOF(name->len, valuelen));
> +	new->xattri_ip = dp;
> +	new->xattri_op_flags = XFS_ATTR_OP_FLAGS_SET;
> +	new->xattri_name_len = name->len;
> +	new->xattri_value_len = valuelen;
> +	new->xattri_flags = name->type;
> +	memcpy(&name_value[0], name->name, name->len);
> +	new->xattri_name = name_value;
> +	new->xattri_value = name_value + name->len;
> +
> +	if (valuelen > 0)
> +		memcpy(&name_value[name->len], value, valuelen);
> +
> +	xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
> +
> +	return 0;
> +}
> +
>  /*
>   * Generic handler routine to remove a name from an attribute list.
>   * Transitions attribute list from Btree to shortform as necessary.
> @@ -480,6 +523,37 @@ xfs_attr_remove(
>  	return error;
>  }
>  
> +/* Removes an attribute for an inode as a deferred operation */
> +int
> +xfs_attr_remove_deferred(
> +	struct xfs_inode        *dp,
> +	struct xfs_trans	*tp,
> +	struct xfs_name		*name)
> +{
> +
> +	struct xfs_attr_item	*new;
> +	char			*name_value;
> +
> +	if (!name->len) {
> +		ASSERT(0);
> +		return -EINVAL;
> +	}
> +
> +	new = kmem_alloc(XFS_ATTR_ITEM_SIZEOF(name->len, 0), KM_SLEEP|KM_NOFS);
> +	name_value = ((char *)new) + sizeof(struct xfs_attr_item);
> +	memset(new, 0, XFS_ATTR_ITEM_SIZEOF(name->len, 0));
> +	new->xattri_ip = dp;
> +	new->xattri_op_flags = XFS_ATTR_OP_FLAGS_REMOVE;
> +	new->xattri_name_len = name->len;
> +	new->xattri_value_len = 0;
> +	new->xattri_flags = name->type;
> +	memcpy(name_value, name->name, name->len);
> +
> +	xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);

Can the common parts of these two functions be refactored into a single
initialization function called from xfs_attr_{set,remove}_deferred,
similar to what xfs_rmap.c does for all the various deferred rmap calls?

--D

> +
> +	return 0;
> +}
> +
>  /*========================================================================
>   * External routines when attribute list is inside the inode
>   *========================================================================*/
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index 9132d4f..0bade83 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -177,5 +177,10 @@ bool xfs_attr_namecheck(const void *name, size_t length);
>  int xfs_attr_args_init(struct xfs_da_args *args, struct xfs_inode *dp,
>  		       struct xfs_name *name);
>  int xfs_attr_calc_size(struct xfs_da_args *args, int *local);
> +int xfs_attr_set_deferred(struct xfs_inode *dp, struct xfs_trans *tp,
> +			  struct xfs_name *name, const unsigned char *value,
> +			  unsigned int valuelen);
> +int xfs_attr_remove_deferred(struct xfs_inode *dp, struct xfs_trans *tp,
> +			    struct xfs_name *name);
>  
>  #endif	/* __XFS_ATTR_H__ */
> -- 
> 2.7.4
>