linux-kernel - [PATCH 1/1] jbd2: fix incorrect unlock on j_list

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Date:	Tue, 17 Mar 2015 22:08:38 -0400
From:	Taesoo Kim <tsgatesv@...il.com>
To:	tytso@....edu, linux-ext4@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc:	taesoo@...ech.edu, changwoo@...ech.edu, sanidhya@...ech.edu,
	blee@...ech.edu, csong84@...ech.edu,
	Taesoo Kim <tsgatesv@...il.com>
Subject: [PATCH 1/1] jbd2: fix incorrect unlock on j_list_lock

When 'jh->b_transaction == transaction' (asserted by below)

  J_ASSERT_JH(jh, (jh->b_transaction == transaction || ...

'journal->j_list_lock' will be incorrectly unlocked, since
the the lock is aquired only at the end of if / else-if
statements (missing the else case).

Signed-off-by: Taesoo Kim <tsgatesv@...il.com>
---
 fs/jbd2/transaction.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 5f09370..edb7f59 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1091,6 +1091,7 @@ int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
 		JBUFFER_TRACE(jh, "file as BJ_Reserved");
 		spin_lock(&journal->j_list_lock);
 		__jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
+		spin_unlock(&journal->j_list_lock);
 	} else if (jh->b_transaction == journal->j_committing_transaction) {
 		/* first access by this transaction */
 		jh->b_modified = 0;
@@ -1098,8 +1099,8 @@ int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
 		JBUFFER_TRACE(jh, "set next transaction");
 		spin_lock(&journal->j_list_lock);
 		jh->b_next_transaction = transaction;
+		spin_unlock(&journal->j_list_lock);
 	}
-	spin_unlock(&journal->j_list_lock);
 	jbd_unlock_bh_state(bh);

 	/*
--
2.3.3

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