drbd: Improve how conflicting writes are handled

Browse source

The previous algorithm for dealing with overlapping concurrent writes
was generating unnecessary warnings for scenarios which could be
legitimate, and did not always handle partially overlapping requests
correctly.  Improve it algorithm as follows:

* While local or remote write requests are in progress, conflicting new
  local write requests will be delayed (commit 82172f7).

* When a conflict between a local and remote write request is detected,
  the node with the discard flag decides how to resolve the conflict: It
  will ask its peer to discard conflicting requests which are fully
  contained in the local request and retry requests which overlap only
  partially.  This involves a protocol change.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

...

This commit is contained in:

Andreas Gruenbacher 2011-02-22 02:15:32 +01:00 • committed by Philipp Reisner

parent 71b1c1eb9c

commit 7be8da0798

5 changed files with 351 additions and 191 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

15

drivers/block/drbd/drbd_int.h

View file

35

drivers/block/drbd/drbd_main.c

View file

410

drivers/block/drbd/drbd_receiver.c

View file

75

drivers/block/drbd/drbd_req.c

View file

7

drivers/block/drbd/drbd_req.h

View file