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| author | Heinz Mauelshagen <heinzm@redhat.com> | 2016-11-24 18:53:44 +0100 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2016-12-08 14:13:11 -0500 |
| commit | affa9d28f7e9a802c8f497ed54fe79a5689d95e9 (patch) | |
| tree | cebf2ead1388719608217faddd9fa5543e1b72b1 /drivers/md | |
| parent | 54cd640d20de46bb54747286ca19f3995be921f2 (diff) | |
| download | lwn-affa9d28f7e9a802c8f497ed54fe79a5689d95e9.tar.gz lwn-affa9d28f7e9a802c8f497ed54fe79a5689d95e9.zip | |
dm raid: don't allow "write behind" with raid4/5/6
Remove CTR_FLAG_MAX_WRITE_BEHIND from raid4/5/6's valid ctr flags.
Only the md raid1 personality supports setting a maximum number
of "write behind" write IOs on any legs set to "write mostly".
"write mostly" enhances throughput with slow links/disks.
Technically the "write behind" value is a write intent bitmap
property only being respected by the raid1 personality. It allows a
maximum number of "write behind" writes to any "write mostly" raid1
mirror legs to be delayed and avoids reads from such legs.
No other MD personalities supported via dm-raid make use of "write
behind", thus setting this property is superfluous; it wouldn't cause
harm but it is correct to reject it.
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm-raid.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 698b03e9d955..9d5c6bb9e35b 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -160,7 +160,6 @@ struct raid_dev { CTR_FLAG_DAEMON_SLEEP | \ CTR_FLAG_MIN_RECOVERY_RATE | \ CTR_FLAG_MAX_RECOVERY_RATE | \ - CTR_FLAG_MAX_WRITE_BEHIND | \ CTR_FLAG_STRIPE_CACHE | \ CTR_FLAG_REGION_SIZE | \ CTR_FLAG_DELTA_DISKS | \ @@ -171,7 +170,6 @@ struct raid_dev { CTR_FLAG_DAEMON_SLEEP | \ CTR_FLAG_MIN_RECOVERY_RATE | \ CTR_FLAG_MAX_RECOVERY_RATE | \ - CTR_FLAG_MAX_WRITE_BEHIND | \ CTR_FLAG_STRIPE_CACHE | \ CTR_FLAG_REGION_SIZE | \ CTR_FLAG_DELTA_DISKS | \ |