[v2,0/3] fstests: add patient module remover

Message

Luis Chamberlain Aug. 11, 2021, 3:45 p.m. UTC

This is v2 of my series of enhancements to fstests to deal with
false positives with meta block drivers we use for tests such as
scsi_debug which are caused by races by not being able to remove
a driver.

Changes in v2:

  - Now that I have confirmed the issue with the refcnt being bumped
    after it becomes 0 is also present on linux-next, and *is* a generic
    "this is life with modules" matter, I went ahead and implemented
    a patient module remover support into kmod and posted patches.
    What this means for this series of patches is that we get a real
    patient module remover support in modprobe, and so modprobe -p
    will soon be an option, if merged. This series then now checks for
    that and if its present uses it, otherwise it open codes a similar
    solution.

  - The patient module remover now also re-tries to remove the module,
    as *any* race can easily bump a module refcnt up. We just then need
    an upper limit threshold on timeout or to decide if we run forever.

  - adds udevadm settle after pvremove

  - I confirm now I don't get any stupid module false positives on older
    or newer kernels, and life can move on.

Luis Chamberlain (3):
  fstests: use udevadm settle after pvremove
  common/module: add patient module rmmod support
  common/scsi_debug: use the patient module remover

 common/config     |  31 ++++++++++++++
 common/module     | 107 ++++++++++++++++++++++++++++++++++++++++++++++
 common/scsi_debug |   6 ++-
 tests/generic/081 |   5 ++-
 tests/generic/108 |   1 +
 tests/generic/459 |   1 +
 6 files changed, 148 insertions(+), 3 deletions(-)