33 lines
1.0 KiB
Diff
33 lines
1.0 KiB
Diff
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From: Joe Thornber <ejt@redhat.com>
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Date: Thu, 27 Nov 2014 12:21:08 +0000
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Subject: [PATCH] dm cache: only use overwrite optimisation for promotion when
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in writeback mode
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Overwrite causes the cache block and origin blocks to diverge, which
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is only allowed in writeback mode.
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Signed-off-by: Joe Thornber <ejt@redhat.com>
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Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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Cc: stable@vger.kernel.org
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---
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drivers/md/dm-cache-target.c | 3 ++-
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1 file changed, 2 insertions(+), 1 deletion(-)
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diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
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index 7130505c2425..6f7086355691 100644
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--- a/drivers/md/dm-cache-target.c
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+++ b/drivers/md/dm-cache-target.c
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@@ -1070,7 +1070,8 @@ static void issue_copy(struct dm_cache_migration *mg)
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avoid = is_discarded_oblock(cache, mg->new_oblock);
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- if (!avoid && bio_writes_complete_block(cache, bio)) {
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+ if (writeback_mode(&cache->features) &&
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+ !avoid && bio_writes_complete_block(cache, bio)) {
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issue_overwrite(mg, bio);
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return;
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}
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--
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2.1.0
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