md/raid5: simplfy delaying of writes while metadata is updated.
If a device fails during a write, we must ensure the failure is recorded in the metadata before the completion of the write is acknowleged. Commit c3cce6cd ("md/raid5: ensure device failure recorded before write request returns.") added code for this, but it was unnecessarily complicated. We already had similar functionality for handling updates to the bad-block-list, thanks to Commit de393cde ("md: make it easier to wait for bad blocks to be acknowledged.") So revert most of the former commit, and instead avoid collecting completed writes if MD_CHANGE_PENDING is set. raid5d() will then flush the metadata and retry the stripe_head. As this change can leave a stripe_head ready for handling immediately after handle_active_stripes() returns, we change raid5_do_work() to pause when MD_CHANGE_PENDING is set, so that it doesn't spin. We check MD_CHANGE_PENDING *after* analyse_stripe() as it could be set asynchronously. After analyse_stripe(), we have collected stable data about the state of devices, which will be used to make decisions. Signed-off-by:NeilBrown <neilb@suse.com> Signed-off-by:
Shaohua Li <shli@fb.com>
parent
49728050
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