[PATCHSET 2/2] fstests: capture logs from mount failures

Hi all,

Whenever a mount fails, we should capture the kernel logs for the last
few seconds before the failure.  If the test fails, retain the log
contents for further analysis.

If you're going to start using this code, I strongly recommend pulling
from my git trees, which are linked below.

With a bit of luck, this should all go splendidly.
Comments and questions are, as always, welcome.

--D

fstests git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=capture-mount-failures
---
Commits in this patchset:
 * treewide: convert all $MOUNT_PROG to _mount
 * check: capture dmesg of mount failures if test fails
---
 check                  |   22 +++++++++++++++++++++-
 common/btrfs           |    4 ++--
 common/dmdelay         |    2 +-
 common/dmerror         |    2 +-
 common/dmlogwrites     |    2 +-
 common/overlay         |    6 +++---
 common/rc              |   26 +++++++++++++++++++++++++-
 common/report          |    8 ++++++++
 doc/xunit.xsd          |   12 +++++++++++-
 tests/btrfs/012        |    6 +++---
 tests/btrfs/075        |    2 +-
 tests/btrfs/089        |    2 +-
 tests/btrfs/136        |    4 ++--
 tests/btrfs/208        |    2 +-
 tests/btrfs/330        |    2 +-
 tests/btrfs/335        |    2 +-
 tests/ext4/032         |    2 +-
 tests/generic/067      |    4 ++--
 tests/generic/089      |    2 +-
 tests/generic/120      |    2 +-
 tests/generic/306      |    2 +-
 tests/generic/361      |    2 +-
 tests/generic/373      |    2 +-
 tests/generic/374      |    2 +-
 tests/generic/395      |    4 ++--
 tests/generic/409      |    6 +++---
 tests/generic/410      |    8 ++++----
 tests/generic/411      |    8 ++++----
 tests/generic/504      |    4 ++--
 tests/generic/589      |    8 ++++----
 tests/generic/631      |    2 +-
 tests/generic/717      |    2 +-
 tests/overlay/005      |    4 ++--
 tests/overlay/025      |    2 +-
 tests/overlay/062      |    2 +-
 tests/overlay/083      |    6 +++---
 tests/overlay/086      |   12 ++++++------
 tests/selftest/008     |   20 ++++++++++++++++++++
 tests/selftest/008.out |    1 +
 tests/xfs/044          |    2 +-
 tests/xfs/049          |    8 ++++----
 tests/xfs/149          |    4 ++--
 tests/xfs/206          |    2 +-
 tests/xfs/250          |    2 +-
 tests/xfs/289          |    4 ++--
 tests/xfs/300          |    2 +-
 tests/xfs/507          |    2 +-
 tests/xfs/544          |    2 +-
 48 files changed, 161 insertions(+), 78 deletions(-)
 create mode 100755 tests/selftest/008
 create mode 100644 tests/selftest/008.out