[Ocfs2-devel] [PATCH] ocfs2: call ocfs2_abort when journal abort

[Andrew Morton]

On Fri, 18 Dec 2015 15:19:25 +0800 Ryan Ding <ryan.ding at oracle.com> wrote:

> orabug: 22293201
> 
> journal can not recover from abort state, so we should take following action to
> prevent file system from corruption:
> 
> 1. change to readonly filesystem when local mount. We can not afford further
>    write, so change to RO state is reasonable.
> 
> 2. panic when cluster mount. Because we can not release lock resource in this
>    state, other node will hung when it require a lock owned by this node. So
>    panic and remaster is a reasonable choise.
> 
> ocfs2_abort() will do all the above work.
> 
> ...
>
> --- a/fs/ocfs2/journal.c
> +++ b/fs/ocfs2/journal.c
> @@ -30,7 +30,6 @@
>  #include <linux/kthread.h>
>  #include <linux/time.h>
>  #include <linux/random.h>
> -#include <linux/delay.h>
>  
>  #include <cluster/masklog.h>
>  
> @@ -2265,7 +2264,7 @@ static int __ocfs2_wait_on_mount(struct ocfs2_super *osb, int quota)
>  
>  static int ocfs2_commit_thread(void *arg)
>  {
> -	int status;
> +	int status = 0;
>  	struct ocfs2_super *osb = arg;
>  	struct ocfs2_journal *journal = osb->journal;
>  
> @@ -2279,22 +2278,18 @@ static int ocfs2_commit_thread(void *arg)
>  		wait_event_interruptible(osb->checkpoint_event,
>  					 atomic_read(&journal->j_num_trans)
>  					 || kthread_should_stop());
> +		if (status < 0)
> +			/* As we can not terminate by myself, just enter an
> +			 * empty loop to wait for stop. */
> +			continue;

This is a busy-wait loop, isn't it?  That's going to chew lots of CPU
and in some situations (eg, SMP=n, PREEMPT=n) it will lock up the
kernel because kjournald will never run.

>  		status = ocfs2_commit_cache(osb);
> -		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);
> -			/*
> -			 * After ocfs2_commit_cache() fails, j_num_trans has a
> -			 * non-zero value.  Sleep here to avoid a busy-wait
> -			 * loop.
> -			 */
> -			msleep_interruptible(1000);
> -		}
> +		if (status < 0)
> +			/* journal can not recover from abort state, there is
> +			 * no need to keep commit cache. So we should either
> +			 * change to readonly(local mount) or just panic
> +			 * (cluster mount). */
> +			ocfs2_abort(osb->sb, "Detected aborted journal");

Coding-style issues:

It would be more conventional to add braces for the comment:

		if (status < 0) {
			/* journal can not recover from abort state, there is
			 * no need to keep commit cache. So we should either
			 * change to readonly(local mount) or just panic
			 * (cluster mount). */
			ocfs2_abort(osb->sb, "Detected aborted journal");
		}

And to lay out the comment like this:

			/*
			 * journal can not recover from abort state, there is
			 * no need to keep commit cache. So we should either
			 * change to readonly(local mount) or just panic
			 * (cluster mount).
			 */