Re: [PATCH v16 04/11] xfs: Add helper xfs_attr_set_fmt

[Allison Henderson <allison.henderson@oracle.com>]

On 3/29/21 2:37 AM, Chandan Babu R wrote:
> On 26 Mar 2021 at 06:03, Allison Henderson wrote:
>> This patch adds a helper function xfs_attr_set_fmt.  This will help
>> isolate the code that will require state management from the portions
>> that do not.  xfs_attr_set_fmt returns 0 when the attr has been set and
>> no further action is needed.  It returns -EAGAIN when shortform has been
>> transformed to leaf, and the calling function should proceed the set the
>> attr in leaf form.
> 
> The previous behaviour is maintained across the changes made by this patch.
> 
> Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Great, thanks for the review!
Allison

> 
>>
>> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
>> Reviewed-by: Brian Foster <bfoster@redhat.com>
>>
>> ---
>>   fs/xfs/libxfs/xfs_attr.c | 79 ++++++++++++++++++++++++++++--------------------
>>   1 file changed, 46 insertions(+), 33 deletions(-)
>>
>> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
>> index 5216f67..d46324a 100644
>> --- a/fs/xfs/libxfs/xfs_attr.c
>> +++ b/fs/xfs/libxfs/xfs_attr.c
>> @@ -216,6 +216,48 @@ xfs_attr_is_shortform(
>>   		ip->i_afp->if_nextents == 0);
>>   }
>>   
>> +STATIC int
>> +xfs_attr_set_fmt(
>> +	struct xfs_da_args	*args)
>> +{
>> +	struct xfs_buf          *leaf_bp = NULL;
>> +	struct xfs_inode	*dp = args->dp;
>> +	int			error2, error = 0;
>> +
>> +	/*
>> +	 * Try to add the attr to the attribute list in the inode.
>> +	 */
>> +	error = xfs_attr_try_sf_addname(dp, args);
>> +	if (error != -ENOSPC) {
>> +		error2 = xfs_trans_commit(args->trans);
>> +		args->trans = NULL;
>> +		return error ? error : error2;
>> +	}
>> +
>> +	/*
>> +	 * It won't fit in the shortform, transform to a leaf block.
>> +	 * GROT: another possible req'mt for a double-split btree op.
>> +	 */
>> +	error = xfs_attr_shortform_to_leaf(args, &leaf_bp);
>> +	if (error)
>> +		return error;
>> +
>> +	/*
>> +	 * Prevent the leaf buffer from being unlocked so that a
>> +	 * concurrent AIL push cannot grab the half-baked leaf buffer
>> +	 * and run into problems with the write verifier.
>> +	 */
>> +	xfs_trans_bhold(args->trans, leaf_bp);
>> +	error = xfs_defer_finish(&args->trans);
>> +	xfs_trans_bhold_release(args->trans, leaf_bp);
>> +	if (error) {
>> +		xfs_trans_brelse(args->trans, leaf_bp);
>> +		return error;
>> +	}
>> +
>> +	return -EAGAIN;
>> +}
>> +
>>   /*
>>    * Set the attribute specified in @args.
>>    */
>> @@ -224,8 +266,7 @@ xfs_attr_set_args(
>>   	struct xfs_da_args	*args)
>>   {
>>   	struct xfs_inode	*dp = args->dp;
>> -	struct xfs_buf          *leaf_bp = NULL;
>> -	int			error2, error = 0;
>> +	int			error;
>>   
>>   	/*
>>   	 * If the attribute list is already in leaf format, jump straight to
>> @@ -234,36 +275,9 @@ xfs_attr_set_args(
>>   	 * again.
>>   	 */
>>   	if (xfs_attr_is_shortform(dp)) {
>> -		/*
>> -		 * Try to add the attr to the attribute list in the inode.
>> -		 */
>> -		error = xfs_attr_try_sf_addname(dp, args);
>> -		if (error != -ENOSPC) {
>> -			error2 = xfs_trans_commit(args->trans);
>> -			args->trans = NULL;
>> -			return error ? error : error2;
>> -		}
>> -
>> -		/*
>> -		 * It won't fit in the shortform, transform to a leaf block.
>> -		 * GROT: another possible req'mt for a double-split btree op.
>> -		 */
>> -		error = xfs_attr_shortform_to_leaf(args, &leaf_bp);
>> -		if (error)
>> -			return error;
>> -
>> -		/*
>> -		 * Prevent the leaf buffer from being unlocked so that a
>> -		 * concurrent AIL push cannot grab the half-baked leaf buffer
>> -		 * and run into problems with the write verifier.
>> -		 */
>> -		xfs_trans_bhold(args->trans, leaf_bp);
>> -		error = xfs_defer_finish(&args->trans);
>> -		xfs_trans_bhold_release(args->trans, leaf_bp);
>> -		if (error) {
>> -			xfs_trans_brelse(args->trans, leaf_bp);
>> +		error = xfs_attr_set_fmt(args);
>> +		if (error != -EAGAIN)
>>   			return error;
>> -		}
>>   	}
>>   
>>   	if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
>> @@ -297,8 +311,7 @@ xfs_attr_set_args(
>>   			return error;
>>   	}
>>   
>> -	error = xfs_attr_node_addname(args);
>> -	return error;
>> +	return xfs_attr_node_addname(args);
>>   }
>>   
>>   /*
> 
>