[v2] erofs: clean up zmap.c

  Several trivial cleanups which aren't quite necessary to split:

 - Rename lcluster load functions as well as justify full indexes
   since they are typically used for global deduplication for
   compressed data;

 - Avoid unnecessary lines, comments for simplicity.

No logic changes.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
---
changes since v1:
 - fix a build error of `lcn` in z_erofs_extent_lookback(). 

 fs/erofs/zmap.c | 69 +++++++++++++++++++++----------------------------
 1 file changed, 29 insertions(+), 40 deletions(-)
  

On 2023/6/15 14:44, Gao Xiang wrote:
> Several trivial cleanups which aren't quite necessary to split:
>
>   - Rename lcluster load functions as well as justify full indexes
>     since they are typically used for global deduplication for
>     compressed data;
>
>   - Avoid unnecessary lines, comments for simplicity.
>
> No logic changes.
>
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
> ---
> changes since v1:
>   - fix a build error of `lcn` in z_erofs_extent_lookback().
>
>   fs/erofs/zmap.c | 69 +++++++++++++++++++++----------------------------
>   1 file changed, 29 insertions(+), 40 deletions(-)
>
> diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
> index 920fb4dbc731..1909ddafd9c7 100644
> --- a/fs/erofs/zmap.c
> +++ b/fs/erofs/zmap.c
> @@ -22,8 +22,8 @@ struct z_erofs_maprecorder {
>   	bool partialref;
>   };
>   
> -static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
> -					 unsigned long lcn)
> +static int z_erofs_load_full_lcluster(struct z_erofs_maprecorder *m,
> +				      unsigned long lcn)
>   {
>   	struct inode *const inode = m->inode;
>   	struct erofs_inode *const vi = EROFS_I(inode);
> @@ -226,8 +226,8 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
>   	return 0;
>   }
>   
> -static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
> -					    unsigned long lcn, bool lookahead)
> +static int z_erofs_load_compact_lcluster(struct z_erofs_maprecorder *m,
> +					 unsigned long lcn, bool lookahead)
>   {
>   	struct inode *const inode = m->inode;
>   	struct erofs_inode *const vi = EROFS_I(inode);
> @@ -277,23 +277,23 @@ static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
>   	return unpack_compacted_index(m, amortizedshift, pos, lookahead);
>   }
>   
> -static int z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m,
> -					  unsigned int lcn, bool lookahead)
> +static int z_erofs_load_lcluster_from_disk(struct z_erofs_maprecorder *m,
> +					   unsigned int lcn, bool lookahead)
>   {
> -	const unsigned int datamode = EROFS_I(m->inode)->datalayout;
> -
> -	if (datamode == EROFS_INODE_COMPRESSED_FULL)
> -		return legacy_load_cluster_from_disk(m, lcn);
> -
> -	if (datamode == EROFS_INODE_COMPRESSED_COMPACT)
> -		return compacted_load_cluster_from_disk(m, lcn, lookahead);
> -
> -	return -EINVAL;
> +	switch (EROFS_I(m->inode)->datalayout) {
> +	case EROFS_INODE_COMPRESSED_FULL:
> +		return z_erofs_load_full_lcluster(m, lcn);
> +	case EROFS_INODE_COMPRESSED_COMPACT:
> +		return z_erofs_load_compact_lcluster(m, lcn, lookahead);
> +	default:
> +		return -EINVAL;
> +	}
>   }
>   
>   static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
>   				   unsigned int lookback_distance)
>   {
> +	struct super_block *sb = m->inode->i_sb;
>   	struct erofs_inode *const vi = EROFS_I(m->inode);
>   	const unsigned int lclusterbits = vi->z_logical_clusterbits;
>   
> @@ -301,21 +301,15 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
>   		unsigned long lcn = m->lcn - lookback_distance;
>   		int err;
>   
> -		/* load extent head logical cluster if needed */
> -		err = z_erofs_load_cluster_from_disk(m, lcn, false);
> +		err = z_erofs_load_lcluster_from_disk(m, lcn, false);
>   		if (err)
>   			return err;
>   
>   		switch (m->type) {
>   		case Z_EROFS_LCLUSTER_TYPE_NONHEAD:
> -			if (!m->delta[0]) {
> -				erofs_err(m->inode->i_sb,
> -					  "invalid lookback distance 0 @ nid %llu",
> -					  vi->nid);
> -				DBG_BUGON(1);
> -				return -EFSCORRUPTED;
> -			}
>   			lookback_distance = m->delta[0];
> +			if (!lookback_distance)
> +				goto err_bogus;
>   			continue;
>   		case Z_EROFS_LCLUSTER_TYPE_PLAIN:
>   		case Z_EROFS_LCLUSTER_TYPE_HEAD1:
> @@ -324,16 +318,15 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
>   			m->map->m_la = (lcn << lclusterbits) | m->clusterofs;
>   			return 0;
>   		default:
> -			erofs_err(m->inode->i_sb,
> -				  "unknown type %u @ lcn %lu of nid %llu",
> +			erofs_err(sb, "unknown type %u @ lcn %lu of nid %llu",
>   				  m->type, lcn, vi->nid);
>   			DBG_BUGON(1);
>   			return -EOPNOTSUPP;
>   		}
>   	}
> -
> -	erofs_err(m->inode->i_sb, "bogus lookback distance @ nid %llu",
> -		  vi->nid);
> +err_bogus:
> +	erofs_err(sb, "bogus lookback distance %u @ lcn %lu of nid %llu",
> +		  lookback_distance, m->lcn, vi->nid);
>   	DBG_BUGON(1);
>   	return -EFSCORRUPTED;
>   }
> @@ -365,7 +358,7 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
>   	if (m->compressedblks)
>   		goto out;
>   
> -	err = z_erofs_load_cluster_from_disk(m, lcn, false);
> +	err = z_erofs_load_lcluster_from_disk(m, lcn, false);
>   	if (err)
>   		return err;
>   
> @@ -397,9 +390,8 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
>   			break;
>   		fallthrough;
>   	default:
> -		erofs_err(m->inode->i_sb,
> -			  "cannot found CBLKCNT @ lcn %lu of nid %llu",
> -			  lcn, vi->nid);
> +		erofs_err(sb, "cannot found CBLKCNT @ lcn %lu of nid %llu", lcn,
> +			  vi->nid);
>   		DBG_BUGON(1);
>   		return -EFSCORRUPTED;
>   	}
> @@ -407,9 +399,7 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
>   	map->m_plen = erofs_pos(sb, m->compressedblks);
>   	return 0;
>   err_bonus_cblkcnt:
> -	erofs_err(m->inode->i_sb,
> -		  "bogus CBLKCNT @ lcn %lu of nid %llu",
> -		  lcn, vi->nid);
> +	erofs_err(sb, "bogus CBLKCNT @ lcn %lu of nid %llu", lcn, vi->nid);
>   	DBG_BUGON(1);
>   	return -EFSCORRUPTED;
>   }
> @@ -430,7 +420,7 @@ static int z_erofs_get_extent_decompressedlen(struct z_erofs_maprecorder *m)
>   			return 0;
>   		}
>   
> -		err = z_erofs_load_cluster_from_disk(m, lcn, true);
> +		err = z_erofs_load_lcluster_from_disk(m, lcn, true);
>   		if (err)
>   			return err;
>   
> @@ -477,7 +467,7 @@ static int z_erofs_do_map_blocks(struct inode *inode,
>   	initial_lcn = ofs >> lclusterbits;
>   	endoff = ofs & ((1 << lclusterbits) - 1);
>   
> -	err = z_erofs_load_cluster_from_disk(&m, initial_lcn, false);
> +	err = z_erofs_load_lcluster_from_disk(&m, initial_lcn, false);
>   	if (err)
>   		goto unmap_out;
>   
> @@ -535,8 +525,7 @@ static int z_erofs_do_map_blocks(struct inode *inode,
>   	if (flags & EROFS_GET_BLOCKS_FINDTAIL) {
>   		vi->z_tailextent_headlcn = m.lcn;
>   		/* for non-compact indexes, fragmentoff is 64 bits */
> -		if (fragment &&
> -		    vi->datalayout == EROFS_INODE_COMPRESSED_FULL)
> +		if (fragment && vi->datalayout == EROFS_INODE_COMPRESSED_FULL)
>   			vi->z_fragmentoff |= (u64)m.pblk << 32;
>   	}
>   	if (ztailpacking && m.lcn == vi->z_tailextent_headlcn) {
Reviewed-by: Guo Xuenan <guoxuenan@huaweicloud.com>
  

On Thu, 15 Jun 2023 14:44:21 +0800
Gao Xiang <hsiangkao@linux.alibaba.com> wrote:

> Several trivial cleanups which aren't quite necessary to split:
> 
>  - Rename lcluster load functions as well as justify full indexes
>    since they are typically used for global deduplication for
>    compressed data;
> 
>  - Avoid unnecessary lines, comments for simplicity.
> 
> No logic changes.
> 
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Reviewed-by: Yue Hu <huyue2@coolpad.com>