linux-kernel - [PATCH] erofs: fix up inplace decompression success rate

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Date:   Fri, 14 Oct 2022 14:49:15 +0800
From:   Gao Xiang <hsiangkao@...ux.alibaba.com>
To:     linux-erofs@...ts.ozlabs.org, Chao Yu <chao@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Gao Xiang <hsiangkao@...ux.alibaba.com>
Subject: [PATCH] erofs: fix up inplace decompression success rate

Partial decompression should be checked after updating length.
It's a new regression when introducing multi-reference pclusters.

Fixes: 2bfab9c0edac ("erofs: record the longest decompressed size in this round")
Signed-off-by: Gao Xiang <hsiangkao@...ux.alibaba.com>
---
 fs/erofs/zdata.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index cce56dde135c..2417d7b73622 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -812,15 +812,14 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 	++spiltted;
 	if (fe->pcl->pageofs_out != (map->m_la & ~PAGE_MASK))
 		fe->pcl->multibases = true;
-
-	if ((map->m_flags & EROFS_MAP_FULL_MAPPED) &&
-	    !(map->m_flags & EROFS_MAP_PARTIAL_REF) &&
-	    fe->pcl->length == map->m_llen)
-		fe->pcl->partial = false;
 	if (fe->pcl->length < offset + end - map->m_la) {
 		fe->pcl->length = offset + end - map->m_la;
 		fe->pcl->pageofs_out = map->m_la & ~PAGE_MASK;
 	}
+	if ((map->m_flags & EROFS_MAP_FULL_MAPPED) &&
+	    !(map->m_flags & EROFS_MAP_PARTIAL_REF) &&
+	    fe->pcl->length == map->m_llen)
+		fe->pcl->partial = false;
 next_part:
 	/* shorten the remaining extent to update progress */
 	map->m_llen = offset + cur - map->m_la;
-- 
2.24.4