linux-stable.git/drivers/block/drbd/drbd_worker.c, branch linux-3.5.y

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 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: Fixed an obvious copy-n-paste mistake

2012-05-09T13:15:57+00:00

This bug might have caused troubles if disk-barriers and the ahead-behind
more are enabled at the same time.

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

drbd: Fixed a race condition between detach and start of resync

2012-05-09T13:15:53+00:00

drbd_state_lock() is only there to serialize cluster wide state
changes. Testing the local disk state needs to happen while
holding the global_state_lock.

Otherwise you might see something like this (Oct 6 on kugel)
14:20:24 drbd0: conn( WFSyncUUID -> Connected ) disk( Inconsistent -> Failed )
14:20:24 drbd0: helper command: /sbin/drbdadm before-resync-target minor-0 exit code 0 (0x0)
14:20:24 drbd0: conn( Connected -> SyncTarget ) disk( Failed -> Inconsistent )

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

drbd: fix harmless race to not trigger an ASSERT

2012-05-09T13:15:52+00:00

We have one pre-allocated page to do certain synchronous meta data IO with,
using it is serialized like so:
	drbd_md_get_buffer();
	drbd_md_sync_page_io();
	drbd_md_sync_page_io();
	...
	drbd_md_put_buffer();

In drbd_md_sync_page_io() there is an
	ASSERT(atomic_read(&mdev->md_io_in_use) == 1);

We want to be able to timeout on unresponsive lower level devices, so we
can "detach" in that case. Inside drbd_md_sync_page_io() we grab an extra
reference, to not have a dangling pointer in case a delayed IO eventually
does still complete, even after we "detached" already.

We need to put the extra reference before we signal completion from the
completion handler, or the second drbd_md_sync_page_io() above may
trigger the assert (reference count still 2).

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

drbd: Hold a reference to ldev while doing meta-data IO

2012-05-09T08:31:11+00:00

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

drbd: Keep a reference to the bio until the completion handler finished

2012-05-09T08:28:51+00:00

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

drbd: Implemented wait_until_done_or_disk_failure()

2012-05-09T08:26:51+00:00

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

drbd: Replaced md_io_mutex by an atomic: md_io_in_use

2012-05-09T08:22:31+00:00

The new function drbd_md_get_buffer() aborts waiting for the buffer
in case the disk failes in the meantime.

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

drbd: moved md_io into mdev

2012-05-09T08:17:24+00:00

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