[PATCH v3] erofs-utils: lib: fix incorrect mtime under -Edot-omitted

[Yifan Zhao]

`-Edot-omitted` enables `-E48bits`, which requires specific
configurations for g_sbi.{epoch, build_time}. Currently, the call to
`erofs_sb_set_48bit()` occurs too late in the execution flow, causing
the aforementioned logic to be bypassed and resulting in incorrect
mtimes for all inodes.

This patch moves time initialization logic into `erofs_importer_init()`
to resolve this issue.

Signed-off-by: Yifan Zhao <zhaoyifan28 at huawei.com>
---
 lib/importer.c | 17 +++++++++++++++++
 mkfs/main.c    | 15 ---------------
 2 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/lib/importer.c b/lib/importer.c
index 958a433..b62ec20 100644
--- a/lib/importer.c
+++ b/lib/importer.c
@@ -2,6 +2,7 @@
 /*
  * Copyright (C) 2025 Alibaba Cloud
  */
+#include <sys/time.h>
 #include "erofs/importer.h"
 #include "erofs/config.h"
 #include "erofs/dedupe.h"
@@ -43,6 +44,8 @@ int erofs_importer_init(struct erofs_importer *im)
 	struct erofs_sb_info *sbi = im->sbi;
 	struct erofs_importer_params *params = im->params;
 	const char *subsys = NULL;
+	struct timeval t;
+	s64 mkfs_time = 0;
 	int err;
 
 	erofs_importer_global_init();
@@ -83,6 +86,20 @@ int erofs_importer_init(struct erofs_importer *im)
 
 	if (params->dot_omitted)
 		erofs_sb_set_48bit(sbi);
+
+	sbi->fixed_nsec = 0;
+	if (cfg.c_unix_timestamp != -1) {
+		mkfs_time = cfg.c_unix_timestamp;
+	} else if (!gettimeofday(&t, NULL)) {
+		mkfs_time = t.tv_sec;
+	}
+	if (erofs_sb_has_48bit(sbi)) {
+		sbi->epoch = max_t(s64, 0, mkfs_time - UINT32_MAX);
+		sbi->build_time = mkfs_time - sbi->epoch;
+	} else {
+		sbi->epoch = mkfs_time;
+	}
+
 	return 0;
 
 out_err:
diff --git a/mkfs/main.c b/mkfs/main.c
index 620b1ed..6ee7f54 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -1710,9 +1710,7 @@ int main(int argc, char **argv)
 	};
 	struct erofs_inode *root = NULL;
 	bool tar_index_512b = false;
-	struct timeval t;
 	FILE *blklst = NULL;
-	s64 mkfs_time = 0;
 	int err;
 	u32 crc;
 
@@ -1736,19 +1734,6 @@ int main(int argc, char **argv)
 		goto exit;
 	}
 
-	g_sbi.fixed_nsec = 0;
-	if (cfg.c_unix_timestamp != -1) {
-		mkfs_time = cfg.c_unix_timestamp;
-	} else if (!gettimeofday(&t, NULL)) {
-		mkfs_time = t.tv_sec;
-	}
-	if (erofs_sb_has_48bit(&g_sbi)) {
-		g_sbi.epoch = max_t(s64, 0, mkfs_time - UINT32_MAX);
-		g_sbi.build_time = mkfs_time - g_sbi.epoch;
-	} else {
-		g_sbi.epoch = mkfs_time;
-	}
-
 	err = erofs_dev_open(&g_sbi, cfg.c_img_path, O_RDWR |
 				(incremental_mode ? 0 : O_TRUNC));
 	if (err) {
-- 
2.47.3