Re: [PATCH 06/21] xfs: Add xfs_attr_set_deferred and xfs_attr_remove_deferred

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

On 05/07/2018 03:59 PM, Darrick J. Wong wrote:
> On Sun, May 06, 2018 at 10:24:39AM -0700, Allison Henderson wrote:
>> 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.  We
>> will use these routines later in the parent pointer patches.
>>
>> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
>> ---
>>   fs/xfs/libxfs/xfs_attr.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++
>>   fs/xfs/libxfs/xfs_attr.h |  5 ++++
>>   2 files changed, 74 insertions(+)
>>
>> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
>> index 2f295ca..adbcef2 100644
>> --- a/fs/xfs/libxfs/xfs_attr.c
>> +++ b/fs/xfs/libxfs/xfs_attr.c
>> @@ -468,6 +468,42 @@ xfs_attr_set(
>>   	return error;
>>   }
>>   
>> +/* Sets an attribute for an inode as a deferred operation */
>> +int
>> +xfs_attr_set_deferred(
>> +	struct xfs_inode	*dp,
>> +	struct xfs_defer_ops    *dfops,
>> +	void			*name,
>> +	unsigned int		namelen,
>> +	void			*value,
>> +	unsigned int		valuelen,
>> +	int			flags)
>> +{
>> +
>> +	struct xfs_attr_item	*new;
>> +	char			*name_value;
>> +
>> +	if (!namelen || !valuelen) {
>> +		ASSERT(0);
>> +		return -EFSCORRUPTED;
>> +	}
>> +
>> +	new = kmem_alloc(XFS_ATTR_ITEM_SIZEOF(namelen, valuelen),
>> +			 KM_SLEEP|KM_NOFS);
>> +	name_value = ((char *)new) + sizeof(struct xfs_attr_item);
>> +	memset(new, 0, XFS_ATTR_ITEM_SIZEOF(namelen, valuelen));
>> +	new->xattri_ip = dp;
>> +	new->xattri_op_flags = XFS_ATTR_OP_FLAGS_SET;
>> +	new->xattri_name_len = namelen;
>> +	new->xattri_value_len = valuelen;
>> +	new->xattri_flags = flags;
>> +	memcpy(&name_value[0], name, namelen);
>> +	memcpy(&name_value[namelen], value, valuelen);
> 
> If we're going to keep the inode locked across _defer_finish rolls then
> we need to xfs_defer_ijoin the inode to the dfops so that the inode is
> relogged in each transaction, which prevents the log tail from being
> pinned unnecessarily.  xfs_bmap.c does a similar thing with the deferred
> map/unmap intents.
> 
>> +
>> +	xfs_defer_add(dfops, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
>> +
>> +	return 0;
>> +}
>>   
>>   /*
>>    * Generic handler routine to remove a name from an attribute list.
>> @@ -560,6 +596,39 @@ 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_defer_ops    *dfops,
>> +	void			*name,
>> +	unsigned int		namelen,
>> +	int                     flags)
>> +{
>> +
>> +	struct xfs_attr_item	*new;
>> +	char			*name_value;
>> +
>> +	if (!namelen) {
>> +		ASSERT(0);
>> +		return -EFSCORRUPTED;
>> +	}
>> +
>> +	new = kmem_alloc(XFS_ATTR_ITEM_SIZEOF(namelen, 0), KM_SLEEP|KM_NOFS);
>> +	name_value = ((char *)new) + sizeof(struct xfs_attr_item);
>> +	memset(new, 0, XFS_ATTR_ITEM_SIZEOF(namelen, 0));
>> +	new->xattri_ip = dp;
>> +	new->xattri_op_flags = XFS_ATTR_OP_FLAGS_REMOVE;
>> +	new->xattri_name_len = namelen;
>> +	new->xattri_value_len = 0;
>> +	new->xattri_flags = flags;
>> +	memcpy(name_value, name, namelen);
> 
> Same here.
> 
> --D

Ok, I will add in the xfs_defer_ijoin's.  Thx!

Allison
> 
>> +	xfs_defer_add(dfops, 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 33b33d3..ec26565 100644
>> --- a/fs/xfs/libxfs/xfs_attr.h
>> +++ b/fs/xfs/libxfs/xfs_attr.h
>> @@ -183,5 +183,10 @@ int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
>>   int xfs_attr_args_init(struct xfs_da_args *args, struct xfs_inode *dp,
>>   		       const unsigned char *name, int flags);
>>   int xfs_attr_calc_size(struct xfs_da_args *args, int *local);
>> +int xfs_attr_set_deferred(struct xfs_inode *dp, struct xfs_defer_ops *dfops,
>> +			  void *name, unsigned int name_len, void *value,
>> +			  unsigned int valuelen, int flags);
>> +int xfs_attr_remove_deferred(struct xfs_inode *dp, struct xfs_defer_ops *dfops,
>> +			    void *name, unsigned int namelen, int flags);
>>   
>>   #endif	/* __XFS_ATTR_H__ */
>> -- 
>> 2.7.4
>>
>> --
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