[PATCH 4.9 42/78] jbd2: abort journal if free a async write error metadata buffer

Greg Kroah-Hartman
2020-09-01T17:12:57Z

From: zhangyi (F) <yi.zhang@huawei.com>

[ Upstream commit c044f3d8360d2ecf831ba2cc9f08cf9fb2c699fb ]

If we free a metadata buffer which has been failed to async write out
in the background, the jbd2 checkpoint procedure will not detect this
failure in jbd2_log_do_checkpoint(), so it may lead to filesystem
inconsistency after cleanup journal tail. This patch abort the journal
if free a buffer has write_io_error flag to prevent potential further
inconsistency.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20200620025427.1756360-5-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/jbd2/transaction.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 1478512ecab3e..cfbf5474bccab 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1990,6 +1990,7 @@ int jbd2_journal_try_to_free_buffers(journal_t *journal,
{
struct buffer_head *head;
struct buffer_head *bh;
+ bool has_write_io_error = false;
int ret = 0;

J_ASSERT(PageLocked(page));
@@ -2014,11 +2015,26 @@ int jbd2_journal_try_to_free_buffers(journal_t *journal,
jbd_unlock_bh_state(bh);
if (buffer_jbd(bh))
goto busy;
+
+ /*
+ * If we free a metadata buffer which has been failed to
+ * write out, the jbd2 checkpoint procedure will not detect
+ * this failure and may lead to filesystem inconsistency
+ * after cleanup journal tail.
+ */
+ if (buffer_write_io_error(bh)) {
+ pr_err("JBD2: Error while async write back metadata bh %llu.",
+ (unsigned long long)bh->b_blocknr);
+ has_write_io_error = true;
+ }
} while ((bh = bh->b_this_page) != head);

ret = try_to_free_buffers(page);

busy:
+ if (has_write_io_error)
+ jbd2_journal_abort(journal, -EIO);
+
return ret;
}

--
2.25.1