From be07c4ed4043ab8c26f222348136141335e47a2f Mon Sep 17 00:00:00 2001
From: Duane Griffin <duaneg@dghda.com>
Date: Wed, 22 Oct 2008 14:15:03 -0700
Subject: jbd: abort instead of waiting for nonexistent transactions
The __log_wait_for_space function sits in a loop checkpointing
transactions until there is sufficient space free in the journal.
However, if there are no transactions to be processed (e.g. because the
free space calculation is wrong due to a corrupted filesystem) it will
never progress.
Check for space being required when no transactions are outstanding and
abort the journal instead of endlessly looping.
This patch fixes the bug reported by Sami Liedes at:
http://bugzilla.kernel.org/show_bug.cgi?id=10976
Signed-off-by: Duane Griffin <duaneg@dghda.com>
Tested-by: Sami Liedes <sliedes@cc.hut.fi>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/jbd/checkpoint.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/fs/jbd/checkpoint.c b/fs/jbd/checkpoint.c
index fe852193324..1bd8d4acc6f 100644
--- a/fs/jbd/checkpoint.c
+++ b/fs/jbd/checkpoint.c
@@ -127,14 +127,29 @@ void __log_wait_for_space(journal_t *journal)
/*
* Test again, another process may have checkpointed while we
- * were waiting for the checkpoint lock
+ * 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.
*/
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;
+
+ spin_unlock(&journal->j_list_lock);
spin_unlock(&journal->j_state_lock);
- log_do_checkpoint(journal);
+ if (chkpt) {
+ log_do_checkpoint(journal);
+ } else {
+ printk(KERN_ERR "%s: no transactions\n",
+ __func__);
+ journal_abort(journal, 0);
+ }
+
spin_lock(&journal->j_state_lock);
+ } else {
+ spin_unlock(&journal->j_list_lock);
}
mutex_unlock(&journal->j_checkpoint_mutex);
}
--
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