dm mpath: delay retry of bypassed pg (f220fd4e) · Commits · 戴 / test

If I/O needs retrying and only bypassed priority groups are available, set the pg_init_delay_retry flag to wait before retrying. If, for example, the reason for the bypass is that the controller is getting reset or there is a firmware upgrade happening, retrying right away would cause a flood of log messages and retries for what could be a few seconds or even several minutes. Signed-off-by:

Mike Christie <michaelc@cs.wisc.edu> Acked-by:

Mike Snitzer <snitzer@redhat.com> Signed-off-by:

Alasdair G Kergon <agk@redhat.com>

drivers/md/dm-mpath.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -329,15 +329,19 @@ static void __choose_pgpath(struct multipath *m, size_t nr_bytes)
		/*
		* Loop through priority groups until we find a valid path.
		* First time we skip PGs marked 'bypassed'.
		* Second time we only try the ones we skipped.
		* Second time we only try the ones we skipped, but set
		* pg_init_delay_retry so we do not hammer controllers.
		*/
		do {
		list_for_each_entry(pg, &m->priority_groups, list) {
		if (pg->bypassed == bypassed)
		continue;
		if (!__choose_path_in_pg(m, pg, nr_bytes))
		if (!__choose_path_in_pg(m, pg, nr_bytes)) {
		if (!bypassed)
		m->pg_init_delay_retry = 1;
		return;
		}
		}
		} while (bypassed--);

		failed:

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