[PATCH AUTOSEL 6.1 03/28] fs/ntfs3: Correct hard links updating when dealing with DOS names

[Sasha Levin <sashal@kernel.org>]

From: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

[ Upstream commit 1918c10e137eae266b8eb0ab1cc14421dcb0e3e2 ]

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ntfs3/record.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/fs/ntfs3/record.c b/fs/ntfs3/record.c
index ba336c7280b8..ab03c373cec6 100644
--- a/fs/ntfs3/record.c
+++ b/fs/ntfs3/record.c
@@ -491,8 +491,20 @@ bool mi_remove_attr(struct ntfs_inode *ni, struct mft_inode *mi,
 		return false;
 
 	if (ni && is_attr_indexed(attr)) {
-		le16_add_cpu(&ni->mi.mrec->hard_links, -1);
-		ni->mi.dirty = true;
+		u16 links = le16_to_cpu(ni->mi.mrec->hard_links);
+		struct ATTR_FILE_NAME *fname =
+			attr->type != ATTR_NAME ?
+				NULL :
+				resident_data_ex(attr,
+						 SIZEOF_ATTRIBUTE_FILENAME);
+		if (fname && fname->type == FILE_NAME_DOS) {
+			/* Do not decrease links count deleting DOS name. */
+		} else if (!links) {
+			/* minor error. Not critical. */
+		} else {
+			ni->mi.mrec->hard_links = cpu_to_le16(links - 1);
+			ni->mi.dirty = true;
+		}
 	}
 
 	used -= asize;
-- 
2.43.0