linux-kernel - [PATCH v2 05/13] exfat: remove the check for infinite cluster chain loop

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Message-ID: <20260108074929.356683-6-chizhiling@163.com>
Date: Thu,  8 Jan 2026 15:49:21 +0800
From: Chi Zhiling <chizhiling@....com>
To: linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Namjae Jeon <linkinjeon@...nel.org>,
	Sungjong Seo <sj1557.seo@...sung.com>,
	Yuezhang Mo <yuezhang.mo@...y.com>,
	Chi Zhiling <chizhiling@...inos.cn>
Subject: [PATCH v2 05/13] exfat: remove the check for infinite cluster chain loop

From: Chi Zhiling <chizhiling@...inos.cn>

The infinite cluster chain loop check is not work because the
loop will terminate when fclus reaches the parameter cluster,
and the parameter cluster value is never greater than
ei->valid_size.

The following relationship holds:
'fclus' < 'cluster' ≤ ei->valid_size ≤ sb->num_clusters

The check would only be triggered if a cluster number greater than
sb->num_clusters is passed, but no caller currently does this.

Signed-off-by: Chi Zhiling <chizhiling@...inos.cn>
---
 fs/exfat/cache.c | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/fs/exfat/cache.c b/fs/exfat/cache.c
index 61af3fa05ab7..0ee4bff1cb35 100644
--- a/fs/exfat/cache.c
+++ b/fs/exfat/cache.c
@@ -238,8 +238,6 @@ int exfat_get_cluster(struct inode *inode, unsigned int cluster,
 		unsigned int *last_dclus, int allow_eof)
 {
 	struct super_block *sb = inode->i_sb;
-	struct exfat_sb_info *sbi = EXFAT_SB(sb);
-	unsigned int limit = sbi->num_clusters;
 	struct exfat_inode_info *ei = EXFAT_I(inode);
 	struct exfat_cache_id cid;
 	unsigned int content;
@@ -279,14 +277,6 @@ int exfat_get_cluster(struct inode *inode, unsigned int cluster,
 		return 0;
 
 	while (*fclus < cluster) {
-		/* prevent the infinite loop of cluster chain */
-		if (*fclus > limit) {
-			exfat_fs_error(sb,
-				"detected the cluster chain loop (i_pos %u)",
-				(*fclus));
-			return -EIO;
-		}
-
 		if (exfat_ent_get(sb, *dclus, &content, NULL))
 			return -EIO;
 
-- 
2.43.0