Re: [PATCH v13 06/10] xfs: Add xfs_attr_set_deferred and xfs_attr_remove_deferred

Darrick J. Wong
2020-11-10T20:15:29Z

On Thu, Oct 22, 2020 at 11:34:31PM -0700, Allison Henderson wrote:
> From: Allison Collins <allison.henderson@oracle.com>
>
> These routines to set up and start a new deferred attribute operations.
> These functions are meant to be called by any routine needing to
> initiate a deferred attribute operation as opposed to the existing
> inline operations. New helper function xfs_attr_item_init also added.
>
> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
> ---
> fs/xfs/libxfs/xfs_attr.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
> fs/xfs/libxfs/xfs_attr.h | 2 ++
> 2 files changed, 56 insertions(+)
>
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 760383c..7fe5554 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
> @@ -643,6 +644,59 @@ xfs_attr_set(
> goto out_unlock;
> }
>
> +STATIC int
> +xfs_attr_item_init(
> + struct xfs_da_args *args,
> + unsigned int op_flags, /* op flag (set or remove) */
> + struct xfs_attr_item **attr) /* new xfs_attr_item */
> +{
> +
> + struct xfs_attr_item *new;
> +
> + new = kmem_alloc_large(sizeof(struct xfs_attr_item), KM_NOFS);

I don't think we need _large allocations for struct xfs_attr_item, right?

> + memset(new, 0, sizeof(struct xfs_attr_item));

Use kmem_zalloc and you won't have to memset. Better yet, zalloc will
get you memory that's been pre-zeroed in the background.

> + new->xattri_op_flags = op_flags;
> + new->xattri_dac.da_args = args;
> +
> + *attr = new;
> + return 0;
> +}
> +
> +/* Sets an attribute for an inode as a deferred operation */
> +int
> +xfs_attr_set_deferred(
> + struct xfs_da_args *args)
> +{
> + struct xfs_attr_item *new;
> + int error = 0;
> +
> + error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_SET, &new);
> + if (error)
> + return error;
> +
> + xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
> +
> + return 0;
> +}

The changes in "xfs: enable delayed attributes" should be moved to this
patch so that these new functions immediately have callers.

(Also see the reply I sent to the next patch, which will avoid weird
regressions if someone's bisect lands in the middle of this series...)

--D

> +
> +/* Removes an attribute for an inode as a deferred operation */
> +int
> +xfs_attr_remove_deferred(
> + struct xfs_da_args *args)
> +{
> +
> + struct xfs_attr_item *new;
> + int error;
> +
> + error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_REMOVE, &new);
> + if (error)
> + return error;
> +
> + xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
> +
> + 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 5b4a1ca..8a08411 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -307,5 +307,7 @@ bool xfs_attr_namecheck(const void *name, size_t length);
> void xfs_delattr_context_init(struct xfs_delattr_context *dac,
> struct xfs_da_args *args);
> int xfs_attr_calc_size(struct xfs_da_args *args, int *local);
> +int xfs_attr_set_deferred(struct xfs_da_args *args);
> +int xfs_attr_remove_deferred(struct xfs_da_args *args);
>
> #endif /* __XFS_ATTR_H__ */
> --
> 2.7.4
>