md/raid5: Make sure we clear R5_Discard when discard is finished. (ca64cae9) · Commits · 戴 / test

commit MD: raid5 avoid unnecessary zero page for trim change raid5 to clear R5_Discard when the complete request is handled rather than when submitting the per-device discard request. However it did not clear R5_Discard for the parity device. This means that if the stripe_head was reused before it expired from the cache, the setting would be wrong and a hang would result. Also if the R5_Uptodate bit happens to be set, R5_Discard again won't be cleared. But R5_Uptodate really should be clear at this point. So make sure R5_Discard is cleared in all cases, and clear R5_Uptodate when a 'discard' completes. Signed-off-by:

NeilBrown <neilb@suse.de>

drivers/md/raid5.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -2774,10 +2774,12 @@ static void handle_stripe_clean_event(struct r5conf *conf,
		dev = &sh->dev[i];
		if (!test_bit(R5_LOCKED, &dev->flags) &&
		(test_bit(R5_UPTODATE, &dev->flags) \|\|
		test_and_clear_bit(R5_Discard, &dev->flags))) {
		test_bit(R5_Discard, &dev->flags))) {
		/* We can return any write requests */
		struct bio wbi, wbi2;
		pr_debug("Return write for disc %d\n", i);
		if (test_and_clear_bit(R5_Discard, &dev->flags))
		clear_bit(R5_UPTODATE, &dev->flags);
		wbi = dev->written;
		dev->written = NULL;
		while (wbi && wbi->bi_sector <
		@@ -2795,7 +2797,8 @@ static void handle_stripe_clean_event(struct r5conf *conf,
		!test_bit(STRIPE_DEGRADED, &sh->state),
		0);
		}
		}
		} else if (test_bit(R5_Discard, &sh->dev[i].flags))
		clear_bit(R5_Discard, &sh->dev[i].flags);

		if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
		if (atomic_dec_and_test(&conf->pending_full_writes))

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