revert CA-114341 patches

The CA-114341 patches fail to pass the BST as some curious locking
issues appear. It's not yet clear whether these patches are just wrong
or whether they uncover an existing issue. I'm removing them for now to
unblock the BST and the merge into trunk.

This patch reverts the following commits:
* 8c1c069c: "CA-114341: don't try to reacquire the lock"
* 1f5db2b3: "CA-114341: explicitly use keyword argument"
* a47ceebb: "CA-114341: GC: acquire VDI lock non-blocking"

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Reviewed-by: Germano Percossi <germano.percossi@citrix.com>

GitHub: closes #99 on xapi-project/sm
Revert "CA-114341: check return value of LVHD plugins"

This reverts commit 4bdb01aa761d73519c2e14410a3e63f291918524. We revert
the commit because it uncovers an existing bug (fixing it is not
trivial) and makes the BVT and BST fail, blocking the merge of
trunk-storage into trunk.

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Reviewed-by: Vineeth Thampi Raveendran <vineeth.thampi@citrix.com>

GitHub: closes #100 on xapi-project/sm
CA-126097: Handle vm-clone when VBD is attached.

A clone operation was never performed when the VM is running, as a result
there is no need to pause/unpause tapdisk during the clone operation. With
storage motion in place, there is a change in this behaviour. vm-copy attaches
and activates the VBD, a clone operation during the phase could result
in VHDs in inconsistent state.

Signed-off-by: Vineeth Thampi Raveendran <vineeth.thampi@citrix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@citrix.com>

GitHub: closes #101 on xapi-project/sm
CA-115938: Repair VHD footer in case of a corruption

During a coalesce operation, parent VHDs could end up with corrupt footers
in case of Out of Storage errors. The fix try a repair parent after a
failed coalesced operation. The scenario where runAbortable kills the vhd
coalesce process is also covered.

Signed-off-by: Vineeth Raveendran <vineeth.thampi@citrix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@citrix.com>

GitHub: closes #102 on xapi-project/sm
Revert "Revert "CA-114341: check return value of LVHD plugins""

This reverts commit 7d104f5720b444c67e1303b107d4532a8532e925.

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Reviewed-by: Germano Percossi <germano.percossi@citrix.com>
Revert "revert CA-114341 patches"

This reverts commit 5d1fe87240d43e2c31bce5dade4f6261d234b0f5.

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Reviewed-by: Germano Percossi <germano.percossi@citrix.com>
CA-114341: increase lock retry count

The current value of lock retry is too small and results in VDI.activate
giving up trying to acquire the lock too early. Doubling this value
seems to rectify the problem.

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Reviewed-by: Germano Percossi <germano.percossi@citrix.com>
Merge CA-114341

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>

GitHub: closes #103 on xapi-project/sm