lkml.org 
[lkml]   [2014]   [Jun]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 06/18] drbd: allow write-ordering policy to be bumped up again
Date
From: Lars Ellenberg <lars.ellenberg@linbit.com>

Previously, once you disabled flushes as a means of enforcing
write-ordering, you'd need to detach/re-attach to enable them again.

Allow drbdsetup disk-options to re-enable previously disabled
write-ordering policy options at runtime.

While at it fix RCU in drbd_bump_write_ordering()
max_allowed_wo() uses rcu_dereference, therefore it must
be called within rcu_read_lock()/rcu_read_unlock()

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
drivers/block/drbd/drbd_nl.c | 10 +++++++++-
drivers/block/drbd/drbd_receiver.c | 6 ++++--
2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 0bf8a60..66065e6 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1294,6 +1294,13 @@ static unsigned int drbd_al_extents_max(struct drbd_backing_dev *bdev)
return (al_size_4k - 1) * AL_CONTEXT_PER_TRANSACTION;
}

+static bool write_ordering_changed(struct disk_conf *a, struct disk_conf *b)
+{
+ return a->disk_barrier != b->disk_barrier ||
+ a->disk_flushes != b->disk_flushes ||
+ a->disk_drain != b->disk_drain;
+}
+
int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
{
struct drbd_config_context adm_ctx;
@@ -1400,7 +1407,8 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
else
set_bit(MD_NO_FUA, &device->flags);

- drbd_bump_write_ordering(device->resource, NULL, WO_bdev_flush);
+ if (write_ordering_changed(old_disk_conf, new_disk_conf))
+ drbd_bump_write_ordering(device->resource, NULL, WO_bdev_flush);

drbd_md_sync(device);

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index bb1434d..8d8a6b7 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -1290,7 +1290,8 @@ void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backin
};

pwo = resource->write_ordering;
- wo = min(pwo, wo);
+ if (wo != WO_bdev_flush)
+ wo = min(pwo, wo);
rcu_read_lock();
idr_for_each_entry(&resource->devices, device, vnr) {
if (get_ldev(device)) {
@@ -1300,11 +1301,12 @@ void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backin
put_ldev(device);
}
}
- rcu_read_unlock();

if (bdev)
wo = max_allowed_wo(bdev, wo);

+ rcu_read_unlock();
+
resource->write_ordering = wo;
if (pwo != resource->write_ordering || wo == WO_bdev_flush)
drbd_info(resource, "Method to ensure write ordering: %s\n", write_ordering_str[resource->write_ordering]);
--
1.9.1


\
 
 \ /
  Last update: 2014-06-30 18:41    [W:0.858 / U:0.444 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site