From c240cbb8dce0fda55c526fb6c291da7e04a9ab37 Mon Sep 17 00:00:00 2001
From: Yilin Li <22371230@buaa.edu.cn>
Date: Thu, 8 May 2025 10:27:10 +0800
Subject: [PATCH] nilfs2: add pointer check for nilfs_direct_propagate()

linux-next inclusion
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IC61W6

------------------------------------

from linux-next-20250501
commit df010bbe185f58cd750bdfa827c89703032d8355

This fixes one missed check
for block mapping anomalies
and one improper return of an error code
during a preparation step for log writing,
thereby improving checking for filesystem
corruption on writeback.

This patch (of 2):

In nilfs_direct_propagate(), the pointer
obtained from nilfs_direct_get_ptr()
needs to be checked to ensure it is not
an invalid pointer (NILFS_BMAP_INVALID_PTR).
Add a check and return -EINVAL when invalid,
preventing further corruption.

Fixes: 36a580eb489f ("nilfs2: direct block mapping")
Signed-off-by: Yilin Li <22371230@buaa.edu.cn>
---
 fs/nilfs2/direct.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/nilfs2/direct.c b/fs/nilfs2/direct.c
index 8d769c5dd5dc..0334b33071c0 100644
--- a/fs/nilfs2/direct.c
+++ b/fs/nilfs2/direct.c
@@ -273,6 +273,8 @@ static int nilfs_direct_propagate(struct nilfs_bmap *bmap,
 	dat = nilfs_bmap_get_dat(bmap);
 	key = nilfs_bmap_data_get_key(bmap, bh);
 	ptr = nilfs_direct_get_ptr(bmap, key);
+	if (ptr == NILFS_BMAP_INVALID_PTR)
+		return -EINVAL;
 	if (!buffer_nilfs_volatile(bh)) {
 		oldreq.pr_entry_nr = ptr;
 		newreq.pr_entry_nr = ptr;
-- 
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