Please merge tgt 1.0.63 from Debian (unstable)

debdiff (old/ubuntu) 1.0.62-1ubuntu1 to (new/debian) 1.0.63-1

debdiff (old/ubuntu) 1.0.62-1ubuntu1 to (new/ubuntu) 1.0.63-1ubuntu1

sbuild build log of 1.0.63-1ubuntu1 on amd64

Install log of tgt 1.0.63-1ubuntu1 under lxd machine container.

Discussion from #ubuntu-release

<infinity> rharper: As for the AIO thing, as you understand the code, what are the odds this could have a negative impact on users of other backends if the AIO stuff is broken?
<infinity> rharper: If you're 99% confident that the change is meaningless for people who don't use the feature, then I'm fine with adding it.
<rharper> infinity: ok; re aio; let me look a bit to be certain, libaio is standard stuff; the question is has tgt had aio for quite some time and just not enabled it (and why); debian recently added it
<infinity> rharper: Right, it's obviously been there longer upstream than in Debian, the question is how long and, more importantly, is it isolated enough to not blow up the world for non-AIO users if it sucks.
<infinity> rharper: The latter question being the interesting one. I don't care if the feature it experimental and added last week if it has zero impact on people who don't use it.
<infinity> s/feature it/feature is/
<rharper> understood
<infinity> rharper: Feel free to copy and paste any of the above to the bug, FWIW, and if your conclusion is "yeah, it looks safe enough", no need to round-trip to me again, FFe approved if your best judgement says it's safe.
<rharper> infinity: will do; I need to confirm aio is only enabled via user choice (ie not default); if so then I'd say it's out of the way for anyone except those whom request it;
<infinity> rharper: And if you're less sure, a commitment of "we'll actively watch for explosions and either fix the issues or revert the aio addition", then also approved. :P
<infinity> rharper: With a caveat that "revert the aio addition" can only be a solution pre-release. Once xenial is out the door, you're stuck supporting whatever features we released with.
<infinity> rharper: If you're okay with the above, go nuts.

Linking against libaio allows tgt to use libaio as a backend for submitting IO to the backing device.
The default backend uses pread64/pwrite64. Adding an additional backed does not change this default

For users to consume the aio backend, they must specify the backend type via command line switch (from tgtadm manpage):

-E, --bstype <type>
           When creating a LUN, this parameter specifies the type of backend
           storage to to use.

I believe that aio is out of the way for default users. I'd like to get some testing done on the aio backend before we say we'll support it.

Seems Ryan is still investigating whether or not to enable AIO in the first place. If you decide to disable it, then there's no FFE, and if you want to enable it and can make sure that it does not negatively affect other modes, then Adam already gave the OK.

Old Ubuntu -> New Debian debdiff

Old Ubuntu to New Ubuntu

Dropped AIO enablement; while the feature was isolated, we've had no testing on the aio backend; we can always enable it later if we get enough testing to ensure proper functionality. Therefore dropping the FFE and just requesting a merge with Debian.

Hi, are you sure you uploaded the right debdiff? It looks to me like the one from comment #9 leaves aio enabled...

Now with less libaio-dev in control file for no AIO. Thanks for catching my mistake

That looks better :-) Uploaded with two changes: I put the bug number in the changelog, and I changed the Vcs-* fields in control to what they were in Debian.

This bug was fixed in the package tgt - 1:1.0.63-1ubuntu1

---------------
tgt (1:1.0.63-1ubuntu1) xenial; urgency=medium

  * Merge from Debian (LP: #1555700). Remaining changes:
    - Drop glusterfs support, package not in main.
      - debian/control
      - debian/rules
      - debian/tests/{admin, control, daemon, storage}
      - debian/tgt-glusterfs.install (Deleted)
    - Disable AIO backend support: untested new feature
      - debian/control
      - debian/tests/storage
  * Dropped changes
    - debian/patches/tgtd_dont_fail_on_eacces.patch: included in new release

 -- Ryan Harper <email address hidden> Wed, 09 Mar 2016 16:51:44 -0600