This is a note to let you know that I've just added the patch titled
nilfs2: do not write dirty data after degenerating to read-only
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nilfs2-do-not-write-dirty-data-after-degenerating-to-read-only.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 28a65b49eb53e172d23567005465019658bfdb4d Mon Sep 17 00:00:00 2001
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Date: Thu, 27 Apr 2023 10:15:26 +0900
Subject: nilfs2: do not write dirty data after degenerating to read-only
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
commit 28a65b49eb53e172d23567005465019658bfdb4d upstream.
According to syzbot's report, mark_buffer_dirty() called from
nilfs_segctor_do_construct() outputs a warning with some patterns after
nilfs2 detects metadata corruption and degrades to read-only mode.
After such read-only degeneration, page cache data may be cleared through
nilfs_clear_dirty_page() which may also clear the uptodate flag for their
buffer heads. However, even after the degeneration, log writes are still
performed by unmount processing etc., which causes mark_buffer_dirty() to
be called for buffer heads without the "uptodate" flag and causes the
warning.
Since any writes should not be done to a read-only file system in the
first place, this fixes the warning in mark_buffer_dirty() by letting
nilfs_segctor_do_construct() abort early if in read-only mode.
This also changes the retry check of nilfs_segctor_write_out() to avoid
unnecessary log write retries if it detects -EROFS that
nilfs_segctor_do_construct() returned.
Link: https://lkml.kernel.org/r/20230427011526.13457-1-konishi.ryusuke@xxxxxxxxx
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Tested-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Reported-by: syzbot+2af3bc9585be7f23f290@xxxxxxxxxxxxxxxxxxxxxxxxx
Link: https://syzkaller.appspot.com/bug?extid=2af3bc9585be7f23f290
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/segment.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2039,6 +2039,9 @@ static int nilfs_segctor_do_construct(st
struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
int err;
+ if (sb_rdonly(sci->sc_super))
+ return -EROFS;
+
nilfs_sc_cstage_set(sci, NILFS_ST_INIT);
sci->sc_cno = nilfs->ns_cno;
@@ -2724,7 +2727,7 @@ static void nilfs_segctor_write_out(stru
flush_work(&sci->sc_iput_work);
- } while (ret && retrycount-- > 0);
+ } while (ret && ret != -EROFS && retrycount-- > 0);
}
/**
Patches currently in stable-queue which might be from konishi.ryusuke@xxxxxxxxx are
queue-5.4/nilfs2-do-not-write-dirty-data-after-degenerating-to-read-only.patch
queue-5.4/nilfs2-fix-infinite-loop-in-nilfs_mdt_get_block.patch
