Commit 10d82c5f authored May 08, 2015 by NeilBrown

md/raid5: avoid reading parity blocks for full-stripe write to degraded array



When performing a reconstruct write, we need to read all blocks
that are not being over-written .. except the parity (P and Q) blocks.

The code currently reads these (as they are not being over-written!)
unnecessarily.

Signed-off-by: NeilBrown <neilb@suse.de>
Fixes: ea664c82 ("md/raid5: need_this_block: tidy/fix last condition.")

parent b0c783b3

drivers/md/raid5.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -3282,7 +3282,9 @@ static int need_this_block(struct stripe_head sh, struct stripe_head_state s,
		/* reconstruct-write isn't being forced */
		return 0;
		for (i = 0; i < s->failed; i++) {
		if (!test_bit(R5_UPTODATE, &fdev[i]->flags) &&
		if (s->failed_num[i] != sh->pd_idx &&
		s->failed_num[i] != sh->qd_idx &&
		!test_bit(R5_UPTODATE, &fdev[i]->flags) &&
		!test_bit(R5_OVERWRITE, &fdev[i]->flags))
		return 1;
		}

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