Re: [RFC PATCH 1/4] xfs: introduce a new helper xfs_inobt_reada_chunk()

[Jeff Liu <jeff.liu@oracle.com>]

On 11/18 2013 07:01 PM, Christoph Hellwig wrote:

>>> I'd prefer to factor this out even further. xfs_ialloc_inode_init and
>>> xfs_ifree_cluster already have two pieces of code that calculate these
>>> two (with more readable names) and an additional nuber buffers counter
>>> we won't need here, it might make most sense to factor that into a
>>> single common helper.
>> Yup, I also thought this can be factored out, however, I can not figure out
>> a meaningful function name at that time due to my poor skill...
>>
>> How about if we introduce an inline helper to xfs_ialloc.h as below?
>>
>> /* Helper function to extract the # of blocks/inodes/buffers hint per cluster */
>> static inline void
>> xfs_ialloc_get_cluster_hints(
>> 	struct xfs_mount	*mp,
>> 	int			*nblks;
>> 	int			*ninodes;
>> 	int			*nbufs)
>> {
>> 	....
>> }
> 
> Probably fine to make it an inline.  I don't think we need the nbufs
> parameter, as it requires the length to calculate, and it's a trivial
> length / blks_per_cluster.
> 
> Similarly the ninodes value is trivially calculatable, so it might be
> as easy as:
> 
> static inline int
> xfs_ialloc_blks_per_cluster(struct xfs_mount *mp)
> {
> 	if (mp->m_sb.sb_blocksize >= XFS_INODE_CLUSTER_SIZE(mp))
> 		return 1;
> 	return XFS_INODE_CLUSTER_SIZE(mp) / mp->m_sb.sb_blocksize;
> }
> 
> 
> ...
> 
> 	blks_per_cluster = xfs_ialloc_blks_per_cluster(mp);
> 	nbufs = length / blks_per_cluster;
> 	ninodes = blks_per_cluster * mp->m_sb.sb_inopblock;

Coool, your idea is better than mine.

Thanks,
-Jeff


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