[PATCH v2] erofs-utils: no compression case for tail-end block in vle_write_indexes()

[PATCH v2] erofs-utils: no compression case for tail-end block in vle_write_indexes()

[Yue Hu]

From: Yue Hu <huyue2@yulong.com>

Note that count value will be always greater than EROFS_BLKSIZ when
calling erofs_compress_destsize() in vle_compress_one(). So, the d1
always >= 1 for compressed block in vle_write_indexes(). That is to
say tail-end block can't be compressed.

Signed-off-by: Yue Hu <huyue2@yulong.com>
---
v2: add DBG_BUGON(!raw), a TODO comment.

 lib/compress.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/lib/compress.c b/lib/compress.c
index af0c720..40723a1 100644
--- a/lib/compress.c
+++ b/lib/compress.c
@@ -73,10 +73,11 @@ static void vle_write_indexes(struct z_erofs_vle_compress_ctx *ctx,
 
 	di.di_clusterofs = cpu_to_le16(ctx->clusterofs);
 
-	/* whether the tail-end (un)compressed block or not */
+	/* whether the tail-end uncompressed block or not */
 	if (!d1) {
-		type = raw ? Z_EROFS_VLE_CLUSTER_TYPE_PLAIN :
-			Z_EROFS_VLE_CLUSTER_TYPE_HEAD;
+		/* TODO: tail-packing inline compressed data */
+		DBG_BUGON(!raw);
+		type = Z_EROFS_VLE_CLUSTER_TYPE_PLAIN;
 		advise = cpu_to_le16(type << Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT);
 
 		di.di_advise = advise;
-- 
1.9.1

Re: [PATCH v2] erofs-utils: no compression case for tail-end block in vle_write_indexes()

[Gao Xiang]

On Fri, Jul 23, 2021 at 02:27:39PM +0800, Yue Hu wrote:
> From: Yue Hu <huyue2@yulong.com>
> 
> Note that count value will be always greater than EROFS_BLKSIZ when
> calling erofs_compress_destsize() in vle_compress_one(). So, the d1
> always >= 1 for compressed block in vle_write_indexes(). That is to
> say tail-end block can't be compressed.
> 
> Signed-off-by: Yue Hu <huyue2@yulong.com>

Thanks, looks good to me:
Reviewed-by: Gao Xiang <xiang@kernel.org>

Thanks,
Gao Xiang

> ---
> v2: add DBG_BUGON(!raw), a TODO comment.
> 
>  lib/compress.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/compress.c b/lib/compress.c
> index af0c720..40723a1 100644
> --- a/lib/compress.c
> +++ b/lib/compress.c
> @@ -73,10 +73,11 @@ static void vle_write_indexes(struct z_erofs_vle_compress_ctx *ctx,
>  
>  	di.di_clusterofs = cpu_to_le16(ctx->clusterofs);
>  
> -	/* whether the tail-end (un)compressed block or not */
> +	/* whether the tail-end uncompressed block or not */
>  	if (!d1) {
> -		type = raw ? Z_EROFS_VLE_CLUSTER_TYPE_PLAIN :
> -			Z_EROFS_VLE_CLUSTER_TYPE_HEAD;
> +		/* TODO: tail-packing inline compressed data */
> +		DBG_BUGON(!raw);
> +		type = Z_EROFS_VLE_CLUSTER_TYPE_PLAIN;
>  		advise = cpu_to_le16(type << Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT);
>  
>  		di.di_advise = advise;
> -- 
> 1.9.1