[PATCH v2 4/5] jbd2: Abort journal when detecting metadata writeback error of fs dev

[Zhihao Cheng <chengzhihao1@huawei.com>]

This is a replacement solution of commit bc71726c725767 ("ext4: abort
the filesystem if failed to async write metadata buffer"), JBD2 can
detect metadata writeback error of fs dev by 'j_fs_dev_wb_err'.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/jbd2/transaction.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 5f08b5fd105a..cb0b8d6fc0c6 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1231,11 +1231,25 @@ static bool jbd2_write_access_granted(handle_t *handle, struct buffer_head *bh,
 int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh)
 {
 	struct journal_head *jh;
+	journal_t *journal;
 	int rc;
 
 	if (is_handle_aborted(handle))
 		return -EROFS;
 
+	journal = handle->h_transaction->t_journal;
+	if (jbd2_check_fs_dev_write_error(journal)) {
+		/*
+		 * If the fs dev has writeback errors, it may have failed
+		 * to async write out metadata buffers in the background.
+		 * In this case, we could read old data from disk and write
+		 * it out again, which may lead to on-disk filesystem
+		 * inconsistency. Aborting journal can avoid it happen.
+		 */
+		jbd2_journal_abort(journal, -EIO);
+		return -EIO;
+	}
+
 	if (jbd2_write_access_granted(handle, bh, false))
 		return 0;
 
-- 
2.39.2