After some analysis, it was found that Content.Reader was generally
redudant to an io.ReaderAt. This change removes `Content.Reader` in
favor of a `Content.ReaderAt`. In general, `ReaderAt` can perform better
over interfaces with indeterminant latency because it avoids remote
state for reads. Where a reader is required, a helper is provided to
convert it into an `io.SectionReader`.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Fixes message on pull about a statuses not being found.
These statuses can just be ignored since they are no
longer valid and holding the database lock while reading
statuses is not necessary.
Closes#1231
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
Because the lock on an ingest ref being held regardless of whether a
writer was in use, resuming an existing ingest proved impossible. We now
defer writer locking to the content store backend, where the lock will
be released automatically on closing the writer or on restarting
containerd.
There are still cases where a writer can be abandoned but not closed,
leaving an active ingest, but this is extremely rare and can be resolved
with a daemon restart.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
