From: Theodore Ts'o <tytso@mit.edu>
To: Ext4 Developers List <linux-ext4@vger.kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>, <stable@vger.kernel.org>
Subject: [PATCH 1/3] ext4: avoid kernel warning when writing the superblock to a dead device
Date: Mon, 31 Dec 2018 14:48:34 -0500 [thread overview]
Message-ID: <20181231194836.3761-1-tytso@mit.edu> (raw)
The xfstests generic/475 test switches the underlying device with
dm-error while running a stress test. This results in a large number
of file system errors, and since we can't lock the buffer head when
marking the superblock dirty in the ext4_grp_locked_error() case, it's
possible the superblock to be !buffer_uptodate() without
buffer_write_io_error() being true.
We need to set buffer_uptodate() before we call mark_buffer_dirty() or
this will trigger a WARN_ON. It's safe to do this since the
superblock must have been properly read into memory or the mount would
have been successful. So if buffer_uptodate() is not set, we can
safely assume that this happened due to a failed attempt to write the
superblock.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
---
fs/ext4/super.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index d6c142d73d99..fb12d3c17c1b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4902,7 +4902,7 @@ static int ext4_commit_super(struct super_block *sb, int sync)
ext4_superblock_csum_set(sb);
if (sync)
lock_buffer(sbh);
- if (buffer_write_io_error(sbh)) {
+ if (buffer_write_io_error(sbh) || !buffer_uptodate(sbh)) {
/*
* Oh, dear. A previous attempt to write the
* superblock failed. This could happen because the
--
2.19.1
next reply other threads:[~2018-12-31 19:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-31 19:48 Theodore Ts'o [this message]
2018-12-31 19:48 ` [PATCH 2/3] ext4: use ext4_write_inode() when fsyncing w/o a journal Theodore Ts'o
2019-01-23 11:34 ` Jan Kara
2018-12-31 19:48 ` [PATCH 3/3] ext4: track writeback errors using the generic tracking infrastructure Theodore Ts'o
2019-01-02 14:27 ` [PATCH 1/3] ext4: avoid kernel warning when writing the superblock to a dead device Sasha Levin
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