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Commit 97f06784 authored by Pavel Emelianov's avatar Pavel Emelianov Committed by Linus Torvalds
Browse files

jbd: check for error returned by kthread_create on creating journal thread 



If the thread failed to create the subsequent wait_event will hang forever.

This is likely to happen if kernel hits max_threads limit.

Will be critical for virtualization systems that limit the number of tasks
and kernel memory usage within the container.

(akpm: JBD should be converted fully to the kthread API: kthread_should_stop()
and kthread_stop()).

Cc: <linux-ext4@vger.kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ee6f9582

fs/jbd/journal.c

+9 −4
Original line number Diff line number Diff line
@@ -210,10 +210,16 @@ static int kjournald(void *arg) 
	return 0;

}



static void journal_start_thread(journal_t *journal)

static int journal_start_thread(journal_t *journal)

{

	kthread_run(kjournald, journal, "kjournald");

	struct task_struct *t;



	t = kthread_run(kjournald, journal, "kjournald");

	if (IS_ERR(t))

		return PTR_ERR(t);



	wait_event(journal->j_wait_done_commit, journal->j_task != 0);

	return 0;

}



static void journal_kill_thread(journal_t *journal)
@@ -839,8 +845,7 @@ static int journal_reset(journal_t *journal) 


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

	journal_update_superblock(journal, 1);

	journal_start_thread(journal);

	return 0;

	return journal_start_thread(journal);

}



/**

fs/jbd2/journal.c

+9 −4
Original line number Diff line number Diff line
@@ -210,10 +210,16 @@ static int kjournald2(void *arg) 
	return 0;

}



static void jbd2_journal_start_thread(journal_t *journal)

static int jbd2_journal_start_thread(journal_t *journal)

{

	kthread_run(kjournald2, journal, "kjournald2");

	struct task_struct *t;



	t = kthread_run(kjournald2, journal, "kjournald2");

	if (IS_ERR(t))

		return PTR_ERR(t);



	wait_event(journal->j_wait_done_commit, journal->j_task != 0);

	return 0;

}



static void journal_kill_thread(journal_t *journal)
@@ -839,8 +845,7 @@ static int journal_reset(journal_t *journal) 


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

	jbd2_journal_update_superblock(journal, 1);

	jbd2_journal_start_thread(journal);

	return 0;

	return jbd2_journal_start_thread(journal);

}



/**