linux-ext4 - [PATCH 5/7] ext4: correct behavior under errors=remount-ro mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250117082315.2869996-6-libaokun@huaweicloud.com>
Date: Fri, 17 Jan 2025 16:23:13 +0800
From: libaokun@...weicloud.com
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu,
	adilger.kernel@...ger.ca,
	jack@...e.cz,
	linux-kernel@...r.kernel.org,
	yi.zhang@...wei.com,
	yangerkun@...wei.com,
	libaokun@...weicloud.com,
	Baokun Li <libaokun1@...wei.com>
Subject: [PATCH 5/7] ext4: correct behavior under errors=remount-ro mode

From: Baokun Li <libaokun1@...wei.com>

And after commit 95257987a638 ("ext4: drop EXT4_MF_FS_ABORTED flag") in
v6.6-rc1, the EXT4_FLAGS_SHUTDOWN bit is set in ext4_handle_error() under
errors=remount-ro mode. This causes the read to fail even when the error
is triggered in errors=remount-ro mode.

To correct the behavior under errors=remount-ro, EXT4_FLAGS_SHUTDOWN is
replaced by the newly introduced EXT4_FLAGS_EMERGENCY_RO. This new flag
only prevents writes, matching the previous behavior with SB_RDONLY.

Fixes: 95257987a638 ("ext4: drop EXT4_MF_FS_ABORTED flag")
Closes: https://lore.kernel.org/all/22d652f6-cb3c-43f5-b2fe-0a4bb6516a04@huawei.com/
Suggested-by: Jan Kara <jack@...e.cz>
Signed-off-by: Baokun Li <libaokun1@...wei.com>
---
 fs/ext4/super.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index fc5d30123f22..8d9ac8770764 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -707,11 +707,8 @@ static void ext4_handle_error(struct super_block *sb, bool force_ro, int error,
 	if (test_opt(sb, WARN_ON_ERROR))
 		WARN_ON_ONCE(1);
 
-	if (!continue_fs && !ext4_sb_rdonly(sb)) {
-		set_bit(EXT4_FLAGS_SHUTDOWN, &EXT4_SB(sb)->s_ext4_flags);
-		if (journal)
-			jbd2_journal_abort(journal, -EIO);
-	}
+	if (!continue_fs && !ext4_sb_rdonly(sb) && journal)
+		jbd2_journal_abort(journal, -EIO);
 
 	if (!bdev_read_only(sb->s_bdev)) {
 		save_error_info(sb, error, ino, block, func, line);
@@ -741,13 +738,7 @@ static void ext4_handle_error(struct super_block *sb, bool force_ro, int error,
 		return;
 
 	ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
-	/*
-	 * EXT4_FLAGS_SHUTDOWN was set which stops all filesystem
-	 * modifications. We don't set SB_RDONLY because that requires
-	 * sb->s_umount semaphore and setting it without proper remount
-	 * procedure is confusing code such as freeze_super() leading to
-	 * deadlocks and other problems.
-	 */
+	set_bit(EXT4_FLAGS_EMERGENCY_RO, &EXT4_SB(sb)->s_ext4_flags);
 }
 
 static void update_super_work(struct work_struct *work)
-- 
2.39.2