exfat: fix just enough dentries but allocate a new cluster to dir

JIRA: https://issues.redhat.com/browse/RHEL-89708

This commit fixes the condition for allocating cluster to parent
directory to avoid allocating new cluster to parent directory when
there are just enough empty directory entries at the end of the
parent directory.

Fixes: af02c72 ("exfat: convert exfat_find_empty_entry() to use dentry cache")
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
(cherry picked from commit 6697f81)
Signed-off-by: Pavel Reichl <preichl@redhat.com>

Author: preichl

fs/exfat/namei.c

@@ -237,7 +237,7 @@ static int exfat_search_empty_slot(struct super_block *sb,
 		dentry = 0;
 	}
 
-	while (dentry + num_entries < total_entries &&
+	while (dentry + num_entries <= total_entries &&
 	       clu.dir != EXFAT_EOF_CLUSTER) {
 		i = dentry & (dentries_per_clu - 1);