From: Theodore Ts'o Subject: [PATCH] jbd2: don't give up looking for space so easily in __jbd2_log_wait_for_space Date: Wed, 5 Nov 2008 09:05:08 -0500 Message-ID: <1225893908-2086-2-git-send-email-tytso@mit.edu> References: <20081105135349.GA22998@mit.edu> <1225893908-2086-1-git-send-email-tytso@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Theodore Ts'o , Duane Griffin , Toshiyuki Okajima To: Ext4 Developers List Return-path: Received: from www.church-of-our-saviour.org ([69.25.196.31]:48261 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751227AbYKEOFK (ORCPT ); Wed, 5 Nov 2008 09:05:10 -0500 In-Reply-To: <1225893908-2086-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Commit 23f8b79e introducd a regression because it assumed that if there were no transactions ready to be checkpointed, that no progress could be made on making space available in the journal, and so the journal should be aborted. This assumption is false; it could be the case that simply calling jbd2_cleanup_journal_tail() will recover the necessary space, or, for small journals, the currently committing transaction could be responsible for chewing up the required space in the log, so we need to wait for the currently committing transaction to finish before trying to force a checkpoint operation. This patch fixes a bug reported by Mihai Harpau at: https://bugzilla.redhat.com/show_bug.cgi?id=3D469582 This patch fixes a bug reported by Fran=C3=A7ois Valenduc at: http://bugzilla.kernel.org/show_bug.cgi?id=3D11840 Signed-off-by: "Theodore Ts'o" Cc: Duane Griffin Cc: Toshiyuki Okajima --- fs/jbd2/checkpoint.c | 28 +++++++++++++++++++++++----- 1 files changed, 23 insertions(+), 5 deletions(-) diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c index 9203c33..65605e9 100644 --- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c @@ -129,25 +129,43 @@ void __jbd2_log_wait_for_space(journal_t *journal= ) /* * Test again, another process may have checkpointed while we * were waiting for the checkpoint lock. If there are no - * outstanding transactions there is nothing to checkpoint and - * we can't make progress. Abort the journal in this case. + * transactions ready to be checkpointed, try to recover + * journal space by calling cleanup_journal_tail(), and if + * that doesn't work, by waiting for the currently committing + * transaction to complete. If there is absolutely no way + * to make progress, this is either a BUG or corrupted + * filesystem, so abort the journal and leave a stack + * trace for forensic evidence. */ spin_lock(&journal->j_state_lock); spin_lock(&journal->j_list_lock); nblocks =3D jbd_space_needed(journal); if (__jbd2_log_space_left(journal) < nblocks) { int chkpt =3D journal->j_checkpoint_transactions !=3D NULL; + int tid =3D 0; =20 + if (journal->j_committing_transaction) + tid =3D journal->j_committing_transaction->t_tid; spin_unlock(&journal->j_list_lock); spin_unlock(&journal->j_state_lock); if (chkpt) { jbd2_log_do_checkpoint(journal); + } else if (jbd2_cleanup_journal_tail(journal) =3D=3D 0) { + /* We were able to recover space; yay! */ + ; + } else if (tid) { + jbd2_log_wait_commit(journal, tid); } else { - printk(KERN_ERR "%s: no transactions\n", - __func__); + printk(KERN_ERR "%s: needed %d blocks and " + "only had %d space available\n", + __func__, nblocks, + __jbd2_log_space_left(journal)); + printk(KERN_ERR "%s: no way to get more " + "journal space in %s\n", __func__, + journal->j_devname); + WARN_ON(1); jbd2_journal_abort(journal, 0); }