From c044f3d8360d2ecf831ba2cc9f08cf9fb2c699fb Mon Sep 17 00:00:00 2001
From: "zhangyi (F)" <yi.zhang@huawei.com>
Date: Sat, 20 Jun 2020 10:54:26 +0800
Subject: [PATCH] jbd2: abort journal if free a async write error metadata
 buffer
Git-commit: c044f3d8360d2ecf831ba2cc9f08cf9fb2c699fb
Patch-mainline: v5.9-rc2
References: bsc#1212989

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>
Acked-by: Jan Kara <jack@suse.cz>

---
 fs/jbd2/transaction.c |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)

--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -2020,6 +2020,7 @@ int jbd2_journal_try_to_free_buffers(jou
 {
 	struct buffer_head *head;
 	struct buffer_head *bh;
+	bool has_write_io_error = false;
 	int ret = 0;
 
 	J_ASSERT(PageLocked(page));
@@ -2044,11 +2045,26 @@ int jbd2_journal_try_to_free_buffers(jou
 		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;
 }