From: Theodore Ts'o Subject: [PATCH] jbd: don't give up looking for space so easily in __log_wait_for_space Date: Wed, 5 Nov 2008 09:05:07 -0500 Message-ID: <1225893908-2086-1-git-send-email-tytso@mit.edu> References: <20081105135349.GA22998@mit.edu> 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]:48259 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751154AbYKEOFK (ORCPT ); Wed, 5 Nov 2008 09:05:10 -0500 In-Reply-To: <20081105135349.GA22998@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Commit be07c4ed 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 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 the bug reported by Meelis Roos at: http://bugzilla.kernel.org/show_bug.cgi?id=11937 Signed-off-by: "Theodore Ts'o" Cc: Duane Griffin Cc: Toshiyuki Okajima --- fs/jbd/checkpoint.c | 27 ++++++++++++++++++++++----- 1 files changed, 22 insertions(+), 5 deletions(-) diff --git a/fs/jbd/checkpoint.c b/fs/jbd/checkpoint.c index 1bd8d4a..5e856de 100644 --- a/fs/jbd/checkpoint.c +++ b/fs/jbd/checkpoint.c @@ -128,25 +128,42 @@ void __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 = jbd_space_needed(journal); if (__log_space_left(journal) < nblocks) { int chkpt = journal->j_checkpoint_transactions != NULL; + int tid = 0; + if (journal->j_committing_transaction) + tid = journal->j_committing_transaction->t_tid; spin_unlock(&journal->j_list_lock); spin_unlock(&journal->j_state_lock); if (chkpt) { log_do_checkpoint(journal); + } else if (cleanup_journal_tail(journal) == 0) { + /* We were able to recover space; yay! */ + ; + } else if (tid) { + 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, + __log_space_left(journal)); + printk(KERN_ERR "%s: no way to get more " + "journal space\n", __func__); + WARN_ON(1); journal_abort(journal, 0); }