The sha1sum of a file may update the access time of that file.
If this happens while a brick is down, as it is forced in the
test, that brick doesn't get the update, getting out of sync.

When the brick is restarted, self-heal repairs the file, but
the test shouldn't access brick contents until self-heal finishes.
If this is combined with a kill of another brick before self-heal
has finished repairing the file, the volume could become inaccessible.

Since the purpose of these tests is only to check ec functionality
(there is another test that checks self-heal), the test that corrupts
the file has been removed.

Additional checks to validate the state of the volume have been added
to avoid some timing issues.

BUG: 1144108
Change-Id: Ibd9288de519914663998a1fbc4321ec92ed6082c
Signed-off-by: Xavier Hernandez <xhernandez@datalab.es>
Reviewed-on: http://review.gluster.org/8892
Reviewed-by: Emmanuel Dreyfus <manu@netbsd.org>
Tested-by: Emmanuel Dreyfus <manu@netbsd.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

Two new options have been added to the 'create' command of the cli
interface:

    disperse [<count>] redundancy <count>

Both are optional. A dispersed volume is created by specifying, at
least, one of them. If 'disperse' is missing or it's present but
'<count>' does not, the number of bricks enumerated in the command
line is taken as the disperse count.

If 'redundancy' is missing, the lowest optimal value is assumed. A
configuration is considered optimal (for most workloads) when the
disperse count - redundancy count is a power of 2. If the resulting
redundancy is 1, the volume is created normally, but if it's greater
than 1, a warning is shown to the user and he/she must answer yes/no
to continue volume creation. If there isn't any optimal value for
the given number of bricks, a warning is also shown and, if the user
accepts, a redundancy of 1 is used.

If 'redundancy' is specified and the resulting volume is not optimal,
another warning is shown to the user.

A distributed-disperse volume can be created using a number of bricks
multiple of the disperse count.

Change-Id: Iab93efbe78e905cdb91f54f3741599f7ea6645e4
BUG: 1118629
Signed-off-by: Xavier Hernandez <xhernandez@datalab.es>
Reviewed-on: http://review.gluster.org/7782
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>