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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
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


  parent reply index

Thread overview: 101+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-03 22:05 [PATCH 0/19 v3] ext4: Fix transaction overflow due to revoke descriptors Jan Kara
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 02/22] jbd2: Fixup stale comment in commit code 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
2019-10-03 22:05 ` [PATCH 05/22] ext4: Fix ext4_should_journal_data() for EA inodes Jan Kara
2019-10-21  1:38   ` Theodore Y. Ts'o
2019-10-23 16:55     ` Jan Kara
2019-10-03 22:05 ` [PATCH 06/22] ext4: Use ext4_journal_extend() instead of jbd2_journal_extend() Jan Kara
2019-10-21  1:39   ` Theodore Y. Ts'o
2019-10-03 22:05 ` [PATCH 07/22] ext4: Avoid unnecessary revokes in ext4_alloc_branch() Jan Kara
2019-10-21 13:39   ` Theodore Y. Ts'o
2019-10-03 22:05 ` [PATCH 08/22] ext4: Provide function to handle transaction restarts Jan Kara
2019-10-21 16:20   ` Theodore Y. Ts'o
2019-10-23 16:25     ` Jan Kara
2019-10-03 22:05 ` [PATCH 09/22] ext4, jbd2: Provide accessor function for handle credits Jan Kara
2019-10-21 16:21   ` Theodore Y. Ts'o
2019-10-03 22:05 ` [PATCH 10/22] ocfs2: Use accessor function for h_buffer_credits Jan Kara
2019-10-21 16:21   ` Theodore Y. Ts'o
2019-10-03 22:05 ` [PATCH 11/22] jbd2: Fix statistics for the number of logged blocks Jan Kara
2019-10-21 16:24   ` Theodore Y. Ts'o
2019-10-03 22:05 ` [PATCH 12/22] jbd2: Reorganize jbd2_journal_stop() Jan Kara
2019-10-21 17:29   ` Theodore Y. Ts'o
2019-10-03 22:05 ` [PATCH 13/22] jbd2: Drop pointless check from jbd2_journal_stop() Jan Kara
2019-10-21 17:30   ` Theodore Y. Ts'o
2019-10-03 22:06 ` [PATCH 14/22] jbd2: Drop pointless wakeup " Jan Kara
2019-10-21 17:34   ` Theodore Y. Ts'o
2019-10-03 22:06 ` [PATCH 15/22] jbd2: Factor out common parts of stopping and restarting a handle Jan Kara
2019-10-21 17:49   ` Theodore Y. Ts'o
2019-10-23 16:17     ` Jan Kara
2019-11-04 12:36       ` Theodore Y. Ts'o
2019-11-04 12:59         ` Jan Kara
2019-10-03 22:06 ` [PATCH 16/22] jbd2: Account descriptor blocks into t_outstanding_credits Jan Kara
2019-10-21 21:04   ` Theodore Y. Ts'o
2019-10-23 13:09     ` Jan Kara
2019-10-03 22:06 ` [PATCH 17/22] jbd2: Drop jbd2_space_needed() Jan Kara
2019-10-21 21:05   ` Theodore Y. Ts'o
2019-10-03 22:06 ` [PATCH 18/22] jbd2: Reserve space for revoke descriptor blocks Jan Kara
2019-10-21 21:47   ` Theodore Y. Ts'o
2019-10-23 13:27     ` Jan Kara
2019-10-03 22:06 ` [PATCH 19/22] jbd2: Rename h_buffer_credits to h_total_credits Jan Kara
2019-10-21 21:48   ` Theodore Y. Ts'o
2019-10-03 22:06 ` [PATCH 20/22] jbd2: Make credit checking more strict Jan Kara
2019-10-21 22:29   ` Theodore Y. Ts'o
2019-10-23 13:30     ` Jan Kara
2019-10-03 22:06 ` [PATCH 21/22] ext4: Reserve revoke credits for freed blocks Jan Kara
2019-10-21 23:18   ` Theodore Y. Ts'o
2019-10-23 16:13     ` Jan Kara
2019-11-04 13:08       ` Theodore Y. Ts'o
2019-11-05  8:31         ` Jan Kara
2019-10-03 22:06 ` [PATCH 22/22] jbd2: Provide trace event for handle restarts Jan Kara
2019-10-21 23:18   ` Theodore Y. Ts'o
2019-10-19 19:19 ` [PATCH 0/19 v3] ext4: Fix transaction overflow due to revoke descriptors Theodore Y. Ts'o
2019-10-24 13:09   ` Jan Kara
2019-10-24 15:12     ` Jan Kara
2019-11-04  3:32 ` Theodore Y. Ts'o
2019-11-04 11:22   ` Jan Kara
2019-11-04 13:09     ` Theodore Y. Ts'o
2019-11-05 16:44 ` [PATCH 0/25 " Jan Kara
2019-11-05 16:44 ` Jan Kara [this message]
2019-11-05 16:44 ` [PATCH 02/25] jbd2: Fixup stale comment in commit code Jan Kara
2019-11-05 16:44 ` [PATCH 03/25] jbd2: Completely fill journal descriptor blocks Jan Kara
2019-11-05 16:44 ` [PATCH 04/25] ext4: Move marking of handle as sync to ext4_add_nondir() Jan Kara
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
2019-11-05 16:44 ` [PATCH 07/25] ext4: Fix ext4_should_journal_data() for EA inodes Jan Kara
2019-11-05 16:44 ` [PATCH 08/25] ext4: Use ext4_journal_extend() instead of jbd2_journal_extend() Jan Kara
2019-11-05 16:44 ` [PATCH 09/25] ext4: Avoid unnecessary revokes in ext4_alloc_branch() Jan Kara
2019-11-05 16:44 ` [PATCH 10/25] ext4: Provide function to handle transaction restarts Jan Kara
2019-11-05 16:44 ` [PATCH 11/25] ext4, jbd2: Provide accessor function for handle credits Jan Kara
2019-11-05 16:44 ` [PATCH 12/25] ocfs2: Use accessor function for h_buffer_credits Jan Kara
2019-11-05 16:44 ` [PATCH 13/25] jbd2: Fix statistics for the number of logged blocks Jan Kara
2019-11-05 16:44 ` [PATCH 14/25] jbd2: Reorganize jbd2_journal_stop() Jan Kara
2019-11-05 16:44 ` [PATCH 15/25] jbd2: Drop pointless check from jbd2_journal_stop() Jan Kara
2019-11-05 16:44 ` [PATCH 16/25] jbd2: Drop pointless wakeup " Jan Kara
2019-11-05 16:44 ` [PATCH 17/25] jbd2: Factor out common parts of stopping and restarting a handle Jan Kara
2019-11-05 16:44 ` [PATCH 18/25] jbd2: Account descriptor blocks into t_outstanding_credits Jan Kara
2019-11-05 16:44 ` [PATCH 19/25] jbd2: Drop jbd2_space_needed() Jan Kara
2019-11-05 16:44 ` [PATCH 20/25] jbd2: Reserve space for revoke descriptor blocks Jan Kara
2019-11-15  7:52   ` Eric Biggers
2019-11-15 10:02     ` Jan Kara
2019-11-15 14:20       ` Theodore Y. Ts'o
2019-11-15 17:10         ` Eric Biggers
2019-11-05 16:44 ` [PATCH 21/25] jbd2: Rename h_buffer_credits to h_total_credits Jan Kara
2019-11-05 16:44 ` [PATCH 22/25] jbd2: Make credit checking more strict Jan Kara
2019-11-05 16:44 ` [PATCH 23/25] ext4: Reserve revoke credits for freed blocks Jan Kara
2019-11-05 16:44 ` [PATCH 24/25] jbd2: Provide trace event for handle restarts Jan Kara
2019-11-05 16:44 ` [PATCH 25/25] jbd2: Fine tune estimate of necessary descriptor blocks Jan Kara
2019-11-05 21:04 ` [PATCH 0/25 v3] ext4: Fix transaction overflow due to revoke descriptors Theodore Y. Ts'o
     [not found] ` <20191112220614.GA11089@mit.edu>
     [not found]   ` <20191113094545.GC6367@quack2.suse.cz>
2019-11-14  5:26     ` [PATCH 0/19 " Theodore Y. Ts'o
2019-11-14  8:49       ` Jan Kara

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