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Commit 1ed850f3 authored by NeilBrown's avatar NeilBrown
Browse files

md/raid5: make sure to_read and to_write never go negative. 



to_read and to_write are part of the result of analysing
a stripe before handling it.
Their use is to avoid some loops and tests if the values are
known to be zero.  Thus it is not a problem if they are a
little bit larger than they should be.

So decrementing them in handle_failed_stripe serves little value, and
due to races it could cause some loops to be skipped incorrectly.

So remove those decrements.

Reported-by: default avatar"Jianpeng Ma" <majianpeng@gmail.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent a7854487

drivers/md/raid5.c

+1 −4
Original line number Original line Diff line number Diff line
@@ -2507,10 +2507,8 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh, 
		bi = sh->dev[i].towrite;

		bi = sh->dev[i].towrite;

		sh->dev[i].towrite = NULL;

		sh->dev[i].towrite = NULL;

		spin_unlock_irq(&sh->stripe_lock);

		spin_unlock_irq(&sh->stripe_lock);

		if (bi) {

		if (bi)

			s->to_write--;

			bitmap_end = 1;

			bitmap_end = 1;

		}





		if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))

		if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))

			wake_up(&conf->wait_for_overlap);

			wake_up(&conf->wait_for_overlap);
@@ -2558,7 +2556,6 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh, 
			spin_unlock_irq(&sh->stripe_lock);

			spin_unlock_irq(&sh->stripe_lock);

			if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))

			if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))

				wake_up(&conf->wait_for_overlap);

				wake_up(&conf->wait_for_overlap);

			if (bi) s->to_read--;

			while (bi && bi->bi_sector <

			while (bi && bi->bi_sector <

			       sh->dev[i].sector + STRIPE_SECTORS) {

			       sh->dev[i].sector + STRIPE_SECTORS) {

				struct bio *nextbi =

				struct bio *nextbi =