Commit 1ce8486d authored by Jan Kara's avatar Jan Kara
Browse files

jbd: protect all log tail updates with j_checkpoint_mutex 



There are some log tail updates that are not protected by j_checkpoint_mutex.
Some of these are harmless because they happen during startup or shutdown but
updates in journal_commit_transaction() and journal_flush() can really race
with other log tail updates (e.g. someone doing journal_flush() with someone
running cleanup_journal_tail()). So protect all log tail updates with
j_checkpoint_mutex.

Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 9754e39c

fs/jbd/commit.c

+2 −0
Original line number Diff line number Diff line
@@ -308,7 +308,9 @@ void journal_commit_transaction(journal_t *journal) 
	/* Do we need to erase the effects of a prior journal_flush? */

	if (journal->j_flags & JFS_FLUSHED) {

		jbd_debug(3, "super block updated\n");

		mutex_lock(&journal->j_checkpoint_mutex);

		journal_update_sb_log_tail(journal);

		mutex_unlock(&journal->j_checkpoint_mutex);

	} else {

		jbd_debug(3, "superblock not updated\n");

	}

fs/jbd/journal.c

+15 −1
Original line number Diff line number Diff line
@@ -936,8 +936,11 @@ static int journal_reset(journal_t *journal) 
			journal->j_errno);

		journal->j_flags |= JFS_FLUSHED;

	} else {

		/* Lock here to make assertions happy... */

		mutex_lock(&journal->j_checkpoint_mutex);

		/* Add the dynamic fields and write it to disk. */

		journal_update_sb_log_tail(journal);

		mutex_unlock(&journal->j_checkpoint_mutex);

	}

	return journal_start_thread(journal);

}
@@ -1061,6 +1064,7 @@ void journal_update_sb_log_tail(journal_t *journal) 
{

	journal_superblock_t *sb = journal->j_superblock;



	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));

	spin_lock(&journal->j_state_lock);

	jbd_debug(1,"JBD: updating superblock (start %u, seq %d, errno %d)\n",

		  journal->j_tail, journal->j_tail_sequence, journal->j_errno);
@@ -1089,6 +1093,7 @@ static void mark_journal_empty(journal_t *journal) 
{

	journal_superblock_t *sb = journal->j_superblock;



	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));

	spin_lock(&journal->j_state_lock);

	jbd_debug(1, "JBD: Marking journal as empty (seq %d)\n",

        	  journal->j_tail_sequence);
@@ -1293,6 +1298,8 @@ int journal_destroy(journal_t *journal) 


	/* Force any old transactions to disk */



	/* We cannot race with anybody but must keep assertions happy */

	mutex_lock(&journal->j_checkpoint_mutex);

	/* Totally anal locking here... */

	spin_lock(&journal->j_list_lock);

	while (journal->j_checkpoint_transactions != NULL) {
@@ -1315,6 +1322,7 @@ int journal_destroy(journal_t *journal) 
			err = -EIO;

		brelse(journal->j_sb_buffer);

	}

	mutex_unlock(&journal->j_checkpoint_mutex);



	if (journal->j_inode)

		iput(journal->j_inode);
@@ -1528,6 +1536,7 @@ int journal_flush(journal_t *journal) 
	if (is_journal_aborted(journal))

		return -EIO;



	mutex_lock(&journal->j_checkpoint_mutex);

	cleanup_journal_tail(journal);



	/* Finally, mark the journal as really needing no recovery.
@@ -1536,6 +1545,7 @@ int journal_flush(journal_t *journal) 
	 * commits of data to the journal will restore the current

	 * s_start value. */

	mark_journal_empty(journal);

	mutex_unlock(&journal->j_checkpoint_mutex);

	spin_lock(&journal->j_state_lock);

	J_ASSERT(!journal->j_running_transaction);

	J_ASSERT(!journal->j_committing_transaction);
@@ -1576,8 +1586,12 @@ int journal_wipe(journal_t *journal, int write) 
		write ? "Clearing" : "Ignoring");



	err = journal_skip_recovery(journal);

	if (write)

	if (write) {

		/* Lock to make assertions happy... */

		mutex_lock(&journal->j_checkpoint_mutex);

		mark_journal_empty(journal);

		mutex_unlock(&journal->j_checkpoint_mutex);

	}



 no_recovery:

	return err;

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