Ocfs2 devel - Apr 2014 - [PATCH] ocfs2: limit printk when journal is aborted

Once JBD2_ABORT is set, ocfs2_commit_cache will fail in
ocfs2_commit_thread. Then it will get into a loop with mass logs. This
will meaninglessly consume a larger number of resource and may lead to
system hung at last.
So limit printk in this case.

Signed-off-by: Joseph Qi <joseph.qi at huawei.com>
---
 fs/ocfs2/journal.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index 44fc3e5..cfefbd1 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -30,6 +30,7 @@
 #include <linux/kthread.h>
 #include <linux/time.h>
 #include <linux/random.h>
+#include <linux/delay.h>
 
 #include <cluster/masklog.h>
 
@@ -2191,8 +2192,15 @@ static int ocfs2_commit_thread(void *arg)
 					 || kthread_should_stop());
 
 		status = ocfs2_commit_cache(osb);
-		if (status < 0)
-			mlog_errno(status);
+		if (status < 0) {
+			static unsigned long abort_warn_time;
+
+			/* Warn about this once per minute */
+			if (printk_timed_ratelimit(&abort_warn_time, 60*HZ))
+				mlog(ML_ERROR, "status = %d, journal is "
+						"already aborted.\n", status);
+			msleep_interruptible(1000);
+		}
 
 		if (kthread_should_stop() &&
atomic_read(&journal->j_num_trans)){
 			mlog(ML_KTHREAD,
-- 
1.8.4.3

On Thu, Apr 17, 2014 at 07:08:42PM +0800, Joseph Qi
wrote:
> 
> Once JBD2_ABORT is set, ocfs2_commit_cache will fail in
> ocfs2_commit_thread. Then it will get into a loop with mass logs. This
> will meaninglessly consume a larger number of resource and may lead to
> system hung at last.
> So limit printk in this case.
> 
> Signed-off-by: Joseph Qi <joseph.qi at huawei.com>
> ---
>  fs/ocfs2/journal.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
> index 44fc3e5..cfefbd1 100644
> --- a/fs/ocfs2/journal.c
> +++ b/fs/ocfs2/journal.c
> @@ -30,6 +30,7 @@
>  #include <linux/kthread.h>
>  #include <linux/time.h>
>  #include <linux/random.h>
> +#include <linux/delay.h>
>  
>  #include <cluster/masklog.h>
>  
> @@ -2191,8 +2192,15 @@ static int ocfs2_commit_thread(void *arg)
>  					 || kthread_should_stop());
>  
>  		status = ocfs2_commit_cache(osb);
> -		if (status < 0)
> -			mlog_errno(status);
> +		if (status < 0) {
> +			static unsigned long abort_warn_time;
> +
> +			/* Warn about this once per minute */
> +			if (printk_timed_ratelimit(&abort_warn_time, 60*HZ))
> +				mlog(ML_ERROR, "status = %d, journal is "
> +						"already aborted.\n", status);
> +			msleep_interruptible(1000);
> +		}
Why the msleep? ocfs2_commit_thread will wait on the checkpoint_event queue
right after this anyway - is there a problem with it waiting on that?

Generally I really don't like peppering msleep() into the code where we
might need to sleep - there is often a more elegant solution available.

Thanks,
	--Mark

--
Mark Fasheh