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

Allison Henderson
2020-11-13T01:27:44Z

On 11/10/20 1:15 PM, Darrick J. Wong wrote:
> 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?
I will try it and see, I think it should be ok, one of the new test
cases I'm using does try to progressively add larger and larger attrs.
If it doesnt work, I'll make a note of it though.

>
>> + 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.
Sure, will merge those patches together then

>
> (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
>>