Hi Andrew,
Thanks for you comments, please see my reply:
On 12/19/2015 07:50 AM, Andrew Morton wrote:
> On Fri, 18 Dec 2015 15:19:25 +0800 Ryan Ding <ryan.d...@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.
This will not be a busy loop, because j_num_trans will be 0 here (when
cluster mount, system will panic to prevent further corruption of ocfs2
file system; when local mount, this value will be 0 all the time), so
this thread will always wait on above wait wait_event_interruptible().
But to make code more clearer, I will add code to set j_num_trans to 0in
this function.
>
>> 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).
> */
OK
I will resend v2 patch later.
Thanks,
Ryan
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