(below is a quote from my runc commit 6f82d4b)
TL;DR: check for IsExist(err) after a failed MkdirAll() is both
redundant and wrong -- so two reasons to remove it.
Quoting MkdirAll documentation:
> MkdirAll creates a directory named path, along with any necessary
> parents, and returns nil, or else returns an error. If path
> is already a directory, MkdirAll does nothing and returns nil.
This means two things:
1. If a directory to be created already exists, no error is
returned.
2. If the error returned is IsExist (EEXIST), it means there exists
a non-directory with the same name as MkdirAll need to use for
directory. Example: we want to MkdirAll("a/b"), but file "a"
(or "a/b") already exists, so MkdirAll fails.
The above is a theory, based on quoted documentation and my UNIX
knowledge.
3. In practice, though, current MkdirAll implementation [1] returns
ENOTDIR in most of cases described in #2, with the exception when
there is a race between MkdirAll and someone else creating the
last component of MkdirAll argument as a file. In this very case
MkdirAll() will indeed return EEXIST.
Because of #1, IsExist check after MkdirAll is not needed.
Because of #2 and #3, ignoring IsExist error is just plain wrong,
as directory we require is not created. It's cleaner to report
the error now.
Note this error is all over the tree, I guess due to copy-paste,
or trying to follow the same usage pattern as for Mkdir(),
or some not quite correct examples on the Internet.
[1] https://github.com/golang/go/blob/f9ed2f75/src/os/path.go
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Add details on kernel version, criu, snapshotters, and links to existing
sections for developers/criu details.
Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com>
We can't really use `dlopen()` from a statically built binary, so
let's disable this functionality if `static_build` tag is used
(which is sort of a de-facto standard way of doing it).
This eliminates the following warning:
🇩 bin/containerd
# github.com/containerd/containerd/cmd/containerd
/tmp/go-link-509179974/000004.o: In function `pluginOpen':
/usr/local/go/src/plugin/plugin_dlopen.go:19: warning: Using 'dlopen' in
statically linked applications requires at runtime the shared libraries
from the glibc version used for linking
[v2: add static build instructions to BUILDING.md]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This subreaper should always be turned on for containerd unless
explicitly needed for it to be off.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Could issues where when exec processes fail the wait block is not
released.
Second, you could not dump stacks if the reaper loop locks up.
Third, the publisher was not waiting on the correct pid.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This only performs an unpack if there is an error when creating the
container snapshot (and only if it's a "not found' error) since it should
already be unpacked.
Signed-off-by: Brian Goff <brian.goff@docker.com>
