From: Jan Kara <jack@suse.cz>
To: Ted Tso <tytso@mit.edu>
Cc: <linux-ext4@vger.kernel.org>, Jan Kara <jack@suse.cz>,
stable@vger.kernel.org
Subject: [PATCH 01/25] jbd2: Fix possible overflow in jbd2_log_space_left()
Date: Tue, 5 Nov 2019 17:44:07 +0100 [thread overview]
Message-ID: <20191105164437.32602-1-jack@suse.cz> (raw)
In-Reply-To: <20191003215523.7313-1-jack@suse.cz>
When number of free space in the journal is very low, the arithmetic in
jbd2_log_space_left() could underflow resulting in very high number of
free blocks and thus triggering assertion failure in transaction commit
code complaining there's not enough space in the journal:
J_ASSERT(journal->j_free > 1);
Properly check for the low number of free blocks.
CC: stable@vger.kernel.org
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
---
include/linux/jbd2.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 603fbc4e2f70..10e6049c0ba9 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1582,7 +1582,7 @@ static inline int jbd2_space_needed(journal_t *journal)
static inline unsigned long jbd2_log_space_left(journal_t *journal)
{
/* Allow for rounding errors */
- unsigned long free = journal->j_free - 32;
+ long free = journal->j_free - 32;
if (journal->j_committing_transaction) {
unsigned long committing = atomic_read(&journal->
@@ -1591,7 +1591,7 @@ static inline unsigned long jbd2_log_space_left(journal_t *journal)
/* Transaction + control blocks */
free -= committing + (committing >> JBD2_CONTROL_BLOCKS_SHIFT);
}
- return free;
+ return max_t(long, free, 0);
}
/*
--
2.16.4
next prev parent reply other threads:[~2019-11-05 16:44 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20191003215523.7313-1-jack@suse.cz>
2019-10-03 22:05 ` [PATCH 01/22] jbd2: Fix possible overflow in jbd2_log_space_left() Jan Kara
2019-10-21 1:08 ` Theodore Y. Ts'o
2019-10-03 22:05 ` [PATCH 03/22] ext4: Do not iput inode under running transaction in ext4_mkdir() Jan Kara
2019-10-21 1:21 ` Theodore Y. Ts'o
2019-10-24 10:19 ` Jan Kara
2019-10-24 12:09 ` Theodore Y. Ts'o
2019-10-24 13:37 ` Jan Kara
2019-11-04 12:35 ` Theodore Y. Ts'o
2019-10-03 22:05 ` [PATCH 04/22] ext4: Fix credit estimate for final inode freeing Jan Kara
2019-10-21 1:07 ` Theodore Y. Ts'o
2019-10-24 10:30 ` Jan Kara
2019-11-05 16:44 ` Jan Kara [this message]
2019-11-05 16:44 ` [PATCH 05/25] ext4: Do not iput inode under running transaction Jan Kara
2019-11-05 16:44 ` [PATCH 06/25] ext4: Fix credit estimate for final inode freeing Jan Kara
2019-11-05 21:00 ` Theodore Y. Ts'o
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