From: akpm@linux-foundation.org Subject: [patch 183/455] jbd: check for error returned by kthread_create on creating journal thread Date: Tue, 08 May 2007 00:30:42 -0700 Message-ID: <200705080730.l487Ugir017188@shell0.pdx.osdl.net> Cc: akpm@linux-foundation.org, xemul@sw.ru, hch@lst.de, linux-ext4@vger.kernel.org To: torvalds@linux-foundation.org Return-path: Received: from smtp1.linux-foundation.org ([65.172.181.25]:51554 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934187AbXEHHb4 (ORCPT ); Tue, 8 May 2007 03:31:56 -0400 Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org From: Pavel Emelianov 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: Cc: Christoph Hellwig Signed-off-by: Andrew Morton --- fs/jbd/journal.c | 13 +++++++++---- fs/jbd2/journal.c | 13 +++++++++---- 2 files changed, 18 insertions(+), 8 deletions(-) diff -puN fs/jbd/journal.c~jbd-check-for-error-returned-by-kthread_create-on-creating-journal-thread fs/jbd/journal.c --- a/fs/jbd/journal.c~jbd-check-for-error-returned-by-kthread_create-on-creating-journal-thread +++ a/fs/jbd/journal.c @@ -210,10 +210,16 @@ end_loop: 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 *jour /* 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); } /** diff -puN fs/jbd2/journal.c~jbd-check-for-error-returned-by-kthread_create-on-creating-journal-thread fs/jbd2/journal.c --- a/fs/jbd2/journal.c~jbd-check-for-error-returned-by-kthread_create-on-creating-journal-thread +++ a/fs/jbd2/journal.c @@ -210,10 +210,16 @@ end_loop: 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 *jour /* 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); } /** _