linux-stable.git/drivers/block/drbd/drbd_req.c, branch v3.5

drbd: fix null pointer dereference with on-congestion policy when diskless

2012-06-12T12:35:19+00:00

We must not look at mdev->actlog, unless we have a get_ldev() reference.
It also does not make much sense to try to disconnect or pull-ahead of
the peer, if we don't have good local data.

Only even consider congestion policies, if our local disk is D_UP_TO_DATE.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: fix list corruption by failing but already aborted reads

2012-06-12T12:34:51+00:00

If a read is aborted due to force-detach of a supposedly unresponsive
local backing device, and retried on the peer, it can happen that the
local request later still completes (hopefully with an error).
As it may already have been completed to upper layers meanwhile,
it must not be retried again now.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: Restore the request restart logic

2012-05-09T15:20:59+00:00

It got lost with the commit 5a7bbad27a410350e64a2d7f5ec18fc73836c14f
"block: remove support for bio remapping from ->make_request"

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: fix resend/resubmit of frozen IO

2012-05-09T13:16:58+00:00

DRBD can freeze IO, due to fencing policy (fencing resource-and-stonith),
or because we lost access to data (on-no-data-accessible suspend-io).

Resuming from there (re-connect, or re-attach, or explicit admin
intervention) should "just work".

Unfortunately, if the re-attach/re-connect did not happen within
the timeout, since the commit
  drbd: Implemented real timeout checking for request processing time
if so configured, the request_timer_fn() would timeout and
detach/disconnect virtually immediately.

This change tracks the most recent attach and connect, and does not
timeout within  after attach/connect.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: move put_ldev from __req_mod() to the endio callback

2012-05-09T13:16:51+00:00

One invocation in the endio handler is good enough,
we don't need mention it for each of the different ways
it calls __req_mod().

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: fix WRITE_ACKED_BY_PEER_AND_SIS to not set RQ_NET_DONE

2012-05-09T13:16:50+00:00

Just because this request happened during a resync does
not mean it may pretend to have been barrier-acked.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: fix READ_RETRY_REMOTE_CANCELED to not complete if device is suspended

2012-05-09T13:16:48+00:00

READ_RETRY_REMOTE_CANCELED needs to be grouped with the other _CANCELED
cases, not with CONNECTION_LOST_WHILE_PENDING, as that would complete
(fail) the bio even if the device became suspended.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: make OOS_HANDED_TO_NETWORK its own case

2012-05-09T13:16:47+00:00

OOS_HANDED_TO_NETWORK should not be grouped with the various
*_CANCELED/*_FAILED cases.
Also, not only clear the RQ_NET_QUEUED flag, but also mark it RQ_NET_DONE,
so it can be distinguished from a local-only request even after that.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: fix potential data corruption and protocol error

2012-05-09T13:16:39+00:00

We assumed only bios with bi_idx == 0 would end up
in drbd_make_request().

That is wrong.

At least device mapper, in __clone_and_map(), may submit
clones only covering a partial bio, but sharing
the original bvec, by adjusting bi_idx and relevant
other bio members of the clone.

We used __bio_for_each_segment() in various places,
even though that is documented as
 * drivers should not use the __ version unless they _really_ want to
 * run through the entire bio and not just pending pieces

Impact: we would send the full bio bvec, even for the clone
with bi_idx > 0, which will cause data corruption on the
peer (because we submit wrong data at the clone offset),
and will cause a DRBD protocol error, disconnect/reconnect
and resync (thus fixing the corruption),
because the next package header would be expected right
in the middle of the sent data, causing DRBD magic mismatch.

Fix: drop the assert, and use bio_for_each_segment()
instead of the __ version.

Conflicts:

	drbd/drbd_tracing.c

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: Fix a potential race that could case data inconsistency

2012-05-09T13:16:34+00:00

When we have a write request and a state change C_WF_BITMAP_S -> C_SYNC_SOURCE
at the same time, and it happens that the line

	remote = remote && drbd_should_do_remote(s);

stills sees C_WF_BITMAP_S, and

	send_oos = rw == WRITE && drbd_should_send_oos(s);

already sees C_SYNC_SOURCE both are 0.

This causes the write to not be mirrored, but marked as out-of-sync on the
Sync_Source node.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg