[PATCH v2] erofs-utils: fsck: extract chunk-based file with hole correctly

[Gao Xiang]

On Mon, Apr 22, 2024 at 07:31:32PM +0800, Yifan Zhao wrote:
> Currently fsck skips file extraction if it finds that EROFS_MAP_MAPPED
> is unset, which is not the case for chunk-based files with hole. This
> patch handles the corner case correctly.
> 
> Signed-off-by: Yifan Zhao <zhaoyifan at sjtu.edu.cn>

I will apply the following version:

>From 56e2f73cec3fa45d8b1dd1e9ec571b1f075d2275 Mon Sep 17 00:00:00 2001
From: Yifan Zhao <zhaoyifan at sjtu.edu.cn>
Date: Mon, 22 Apr 2024 19:31:32 +0800
Subject: [PATCH] erofs-utils: fsck: extract chunk-based file with hole correctly

Currently fsck skips file extraction if it finds that EROFS_MAP_MAPPED
is unset, which is not the case for chunk-based files with holes.

This patch handles the corner case correctly.

Signed-off-by: Yifan Zhao <zhaoyifan at sjtu.edu.cn>
Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>
---
 fsck/main.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/fsck/main.c b/fsck/main.c
index e5c37be..4dcb49d 100644
--- a/fsck/main.c
+++ b/fsck/main.c
@@ -470,9 +470,18 @@ static int erofs_verify_inode_data(struct erofs_inode *inode, int outfd)
 		pos += map.m_llen;
 
 		/* should skip decomp? */
-		if (!(map.m_flags & EROFS_MAP_MAPPED) || !fsckcfg.check_decomp)
+		if (map.m_la >= inode->i_size || !fsckcfg.check_decomp)
 			continue;
 
+		if (outfd >= 0 && !(map.m_flags & EROFS_MAP_MAPPED)) {
+			ret = lseek(outfd, map.m_llen, SEEK_CUR);
+			if (ret < 0) {
+				ret = -errno;
+				goto out;
+			}
+			continue;
+		}
+
 		if (map.m_plen > Z_EROFS_PCLUSTER_MAX_SIZE) {
 			if (compressed) {
 				erofs_err("invalid pcluster size %" PRIu64 " @ offset %" PRIu64 " of nid %" PRIu64,
-- 
2.30.2