linux-kernel - [PATCH] exfat: fix erroneous discard when clear cluster bit

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Message-Id: <20210225093333.144829-1-hyeongseok@gmail.com>
Date:   Thu, 25 Feb 2021 18:33:33 +0900
From:   Hyeongseok Kim <hyeongseok@...il.com>
To:     namjae.jeon@...sung.com, sj1557.seo@...sung.com
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Hyeongseok Kim <hyeongseok@...il.com>
Subject: [PATCH] exfat: fix erroneous discard when clear cluster bit

If mounted with discard option, exFAT issues discard command when clear
cluster bit to remove file. But the input parameter of cluster-to-sector
calculation is abnormally adds reserved cluster size which is 2, leading
to discard unrelated sectors included in target+2 cluster.

Fixes: 1e49a94cf707 ("exfat: add bitmap operations")
Signed-off-by: Hyeongseok Kim <hyeongseok@...il.com>
---
 fs/exfat/balloc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c
index 761c79c3a4ba..41a1dfd9d98a 100644
--- a/fs/exfat/balloc.c
+++ b/fs/exfat/balloc.c
@@ -186,8 +186,7 @@ void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync)
 		int ret_discard;
 
 		ret_discard = sb_issue_discard(sb,
-			exfat_cluster_to_sector(sbi, clu +
-						EXFAT_RESERVED_CLUSTERS),
+			exfat_cluster_to_sector(sbi, clu),
 			(1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);
 
 		if (ret_discard == -EOPNOTSUPP) {
-- 
2.27.0.83.g0313f36