Guard operations that mutates an EBS volume with a Mutex

[remilapeyre]

Closes #1284

[CLAassistant]

All committers have signed the CLA.

[codecov-io]

Codecov Report

Merging #1345 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1345   +/-   ##
=======================================
  Coverage   34.20%   34.20%           
=======================================
  Files          36       36           
  Lines        2362     2362           
=======================================
  Hits          808      808           
  Misses       1451     1451           
  Partials      103      103           

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[nbryant42]

Looks good to me, except the attempt to fix the find command in the Makefile is still not quite right.

Merged this into a fork https://github.com/nbryant42/rexray/tree/collected-prs which I am using to build https://gallery.ecr.aws/j1l5j1d1/rexray-ebs

[nbryant42]

On my local branch mentioned above, I now see intermittent mount failures when ECS tries to place a task, with the context deadline exceeded message. Not sure if this PR is missing an edge case that can cause more retries, or if the problem lies elsewhere.

[nbryant42]

Reverted this PR from the binaries I'm publishing, because it seems to be causing regressions.

[nbryant42]

removing approval. seems to cause regressions.