On 03/01/2017 02:20 AM, Shaohua Li wrote:
On Fri, Feb 24, 2017 at 11:15:17AM +0800, Guoqing Jiang wrote:
Since we have switched to sync way to handle METADATA_UPDATED
msg for md-cluster, then process_metadata_update is depended
on mddev->thread->wqueue.
With the new change, clustered raid could possible hang if
array received a METADATA_UPDATED msg after array unregistered
mddev->thread, so we need to stop clustered raid earlier
than before.
And this change should be safe for non-clustered raid since
all writes are stopped before the destroy. Also in md_run,
we activate the personality (pers->run()) before activating
the bitmap (bitmap_create()). So it is pleasingly symmetric
to stop the bitmap (bitmap_destroy()) before stopping the
personality (__md_stop() calls pers->free()).
There is no patch 6. So I can't judge the purpose of the patch.
Sorry, it is resent now.
The patch changed behaviors. We only destroy bitmap with mode == 0, now we do it
even for mode == 2. Please specify why it's safe.
Thanks for reminder, I will add the check for mode.
The __md_stop will wait for
behind writes for example only with bitmap set, but the patch makes us not do
the wait.
I don't know behind write very well, but we have call __md_stop_writes
before
destroy bitmap, also bitmap is flushed. Shouldn't it mean the
behind_writes is
cleared? If not, when the behind_write bit can be cleared? Thanks.
Guoqing
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