[PATCH 5.5 071/399] jbd2: clear JBD2_ABORT flag before journal_reset to update log tail info when load journal

[Greg Kroah-Hartman]

From: Kai Li <li.kai4@xxxxxxx>

[ Upstream commit a09decff5c32060639a685581c380f51b14e1fc2 ]

If the journal is dirty when the filesystem is mounted, jbd2 will replay
the journal but the journal superblock will not be updated by
journal_reset() because JBD2_ABORT flag is still set (it was set in
journal_init_common()). This is problematic because when a new transaction
is then committed, it will be recorded in block 1 (journal->j_tail was set
to 1 in journal_reset()). If unclean shutdown happens again before the
journal superblock is updated, the new recorded transaction will not be
replayed during the next mount (because of stale sb->s_start and
sb->s_sequence values) which can lead to filesystem corruption.

Fixes: 85e0c4e89c1b ("jbd2: if the journal is aborted then don't allow update of the log tail")
Signed-off-by: Kai Li <li.kai4@xxxxxxx>
Link: https://lore.kernel.org/r/20200111022542.5008-1-li.kai4@xxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/jbd2/journal.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index b3e2433f94fe2..6847b18455068 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1711,6 +1711,11 @@ int jbd2_journal_load(journal_t *journal)
 		       journal->j_devname);
 		return -EFSCORRUPTED;
 	}
+	/*
+	 * clear JBD2_ABORT flag initialized in journal_init_common
+	 * here to update log tail information with the newest seq.
+	 */
+	journal->j_flags &= ~JBD2_ABORT;
 
 	/* OK, we've finished with the dynamic journal bits:
 	 * reinitialise the dynamic contents of the superblock in memory
@@ -1718,7 +1723,6 @@ int jbd2_journal_load(journal_t *journal)
 	if (journal_reset(journal))
 		goto recovery_error;
 
-	journal->j_flags &= ~JBD2_ABORT;
 	journal->j_flags |= JBD2_LOADED;
 	return 0;
 
-- 
2.20.1