[PATCH] erofs: unify lcn as u64 for 32-bit platforms

As sashiko reported [1], `lcn` was typed as `unsigned long` (or
`unsigned int` sometimes), which is only 32 bits wide on 32-bit
platforms, which causes `(lcn << lclusterbits)` to be truncated
at 4 GiB.

In order to consolidate the logic, just use `u64` consistently
around the codebase.

[1] https://sashiko.dev/r/20260420034612.1899973-1-hsiangkao%40linux.alibaba.com

Fixes: 152a333a5895 ("staging: erofs: add compacted compression indexes support")
Signed-off-by: Gao Xiang <[email protected]>
---
 fs/erofs/zmap.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 30775502b56d..abf7ddc64c63 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -10,7 +10,7 @@
 struct z_erofs_maprecorder {
 	struct inode *inode;
 	struct erofs_map_blocks *map;
-	unsigned long lcn;
+	u64 lcn;
 	/* compression extent information gathered */
 	u8  type, headtype;
 	u16 clusterofs;
@@ -20,8 +20,7 @@ struct z_erofs_maprecorder {
 	bool partialref, in_mbox;
 };
 
-static int z_erofs_load_full_lcluster(struct z_erofs_maprecorder *m,
-				      unsigned long lcn)
+static int z_erofs_load_full_lcluster(struct z_erofs_maprecorder *m, u64 lcn)
 {
 	struct inode *const inode = m->inode;
 	struct erofs_inode *const vi = EROFS_I(inode);
@@ -94,7 +93,7 @@ static int get_compacted_la_distance(unsigned int lobits,
 }
 
 static int z_erofs_load_compact_lcluster(struct z_erofs_maprecorder *m,
-					 unsigned long lcn, bool lookahead)
+					 u64 lcn, bool lookahead)
 {
 	struct inode *const inode = m->inode;
 	struct erofs_inode *const vi = EROFS_I(inode);
@@ -234,7 +233,7 @@ static int z_erofs_load_compact_lcluster(struct z_erofs_maprecorder *m,
 }
 
 static int z_erofs_load_lcluster_from_disk(struct z_erofs_maprecorder *m,
-					   unsigned int lcn, bool lookahead)
+					   u64 lcn, bool lookahead)
 {
 	struct erofs_inode *vi = EROFS_I(m->inode);
 	int err;
@@ -249,7 +248,7 @@ static int z_erofs_load_lcluster_from_disk(struct z_erofs_maprecorder *m,
 		return err;
 
 	if (m->type >= Z_EROFS_LCLUSTER_TYPE_MAX) {
-		erofs_err(m->inode->i_sb, "unknown type %u @ lcn %u of nid %llu",
+		erofs_err(m->inode->i_sb, "unknown type %u @ lcn %llu of nid %llu",
 			  m->type, lcn, EROFS_I(m->inode)->nid);
 		DBG_BUGON(1);
 		return -EOPNOTSUPP;
@@ -269,7 +268,7 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
 	const unsigned int lclusterbits = vi->z_lclusterbits;
 
 	while (m->lcn >= lookback_distance) {
-		unsigned long lcn = m->lcn - lookback_distance;
+		u64 lcn = m->lcn - lookback_distance;
 		int err;
 
 		if (!lookback_distance)
@@ -286,7 +285,7 @@ static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
 		m->map->m_la = (lcn << lclusterbits) | m->clusterofs;
 		return 0;
 	}
-	erofs_err(sb, "bogus lookback distance %u @ lcn %lu of nid %llu",
+	erofs_err(sb, "bogus lookback distance %u @ lcn %llu of nid %llu",
 		  lookback_distance, m->lcn, vi->nid);
 	DBG_BUGON(1);
 	return -EFSCORRUPTED;
@@ -300,7 +299,7 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
 	struct erofs_inode *vi = EROFS_I(inode);
 	bool bigpcl1 = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
 	bool bigpcl2 = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2;
-	unsigned long lcn = m->lcn + 1;
+	u64 lcn = m->lcn + 1;
 	int err;
 
 	DBG_BUGON(m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD);
@@ -331,7 +330,7 @@ static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
 		  m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD);
 
 	if (m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD && m->delta[0] != 1) {
-		erofs_err(sb, "bogus CBLKCNT @ lcn %lu of nid %llu", lcn, vi->nid);
+		erofs_err(sb, "bogus CBLKCNT @ lcn %llu of nid %llu", lcn, vi->nid);
 		DBG_BUGON(1);
 		return -EFSCORRUPTED;
 	}
-- 
2.43.5