Proof of Conceptt, take 2

Author: ashald

Dockerfile.debian

@@ -0,0 +1,17 @@
+# build
+FROM golang:stretch as builder
+RUN apt update -y && \
+    apt install -y build-essential
+ADD ./ /go/src/github.com/ashald/docker-volume-loopback/
+WORKDIR /go/src/github.com/ashald/docker-volume-loopback
+RUN go build && \
+    mv ./docker-volume-loopback /usr/bin/
+
+
+# package
+FROM debian:stretch-slim
+RUN apt update -y && \
+    apt install -y xfsprogs && \
+    rm -rf /var/lib/apt/lists/*
+COPY --from=builder /usr/bin/docker-volume-loopback /usr/bin/docker-volume-loopback
+CMD [ "/usr/bin/docker-volume-loopback" ]

README.md

@@ -1,133 +1,5 @@
-<h1 align="center">xfsvol 📂  </h1>
-
-<h5 align="center">Docker Volume Plugin for managing local XFS-based volumes</h5>
-
-<br/>
-
-[![Build Status](https://travis-ci.org/cirocosta/xfsvol.svg?branch=master)](https://travis-ci.org/cirocosta/xfsvol)
-
-## Quickstart
-
-1. Create a mountpoint at `/mnt/xfs` and a directory `/mnt/xfs/volumes`. 
-
-For testing purposes this mountpoint can be a loopback device (note: use a loopback device for testing purposes only).
-
-```sh
-sudo dd if=/dev/zero of=/xfs.1G bs=1M count=1024
-sudo losetup /dev/loop0 /xfs.1G
-sudo mkfs -t xfs -n ftype=1 /dev/loop0
-sudo mkdir -p /mnt/xfs/volumes
-sudo mount /dev/loop0 /mnt/xfs -o pquota
-```
-
-2. Install the plugin
-
-```
-docker plugin install \
-        --grant-all-permissions \
-        --alias xfsvol \
-        cirocosta/xfsvol
-
-docker plugin ls
-ID                  NAME                DESCRIPTION                                   ENABLED
-06545b643c6a        xfsvol:latest       Docker plugin to manage XFS-mounted volumes   true
-```
-
-3. Create a named volume
-
-```
-docker volume create \
-        --driver xfsvol \
-        --opt size=10M \
-        myvolume1
-```
-
-4. Run a container with the volume attached
-
-```
-docker run -it \
-        -v myvolume1:/myvolume1 \
-        alpine /bin/sh
-
-dd if=/dev/zero of=/myvolume1/file bs=1M count=100
-(fail!)
-```
-
-5. Check the volumes list
-
-```
-docker volume ls
-DRIVER              VOLUME NAME
-xfsvol:latest       myvolume1 (1.004MB)
-local               dockerdev-go-pkg-cache-gopath
-local               dockerdev-go-pkg-cache-goroot-linux_amd64
-local               dockerdev-go-pkg-cache-goroot-linux_amd64_netgo
-```
-
-and the `xfsvolctl` utility:
-
-```
-sudo /usr/bin/xfsvolctl ls --root /mnt/xfs/volumes/
-NAME   QUOTA
-ciro   1.004 MB
-```
-
-## `xfsvolctl`
-
-This tool is made to help inspect the project quotas created under a given root path as well as create/delete others. It's usage is documented under `--help`:
-
-```
-xfsvolctl --help
-NAME:
-   xfsvolctl - Controls the 'xfsvol' volume plugin
-
-USAGE:
-   xfsvolctl [global options] command [command options] [arguments...]
-
-VERSION:
-   0.0.0
-
-COMMANDS:
-     ls       Lists the volumes managed by 'xfsvol' plugin
-     create   Creates a volume with XFS project quota enforcement
-     delete   Deletes a volume managed by 'xfsvol' plugin
-     help, h  Shows a list of commands or help for one command
-
-GLOBAL OPTIONS:
-   --help, -h     show help
-   --version, -v  print the version
-```
-
-### Under the hood
-
-
-```
-$ sudo mkdir -p /mnt/xfs/tmp/bbb
-$ sudo strace -f xfsvolctl create \
-        --root /mnt/xfs/tmp/bbb \
-        --name ccc \
-        --size 1024 \
-        --inode 1024
-
-stat("/mnt/xfs/tmp/bbb", {st_mode=S_IFDIR|0755, st_size=6, ...}) = 0
-unlinkat(AT_FDCWD, "/mnt/xfs/tmp/bbb/backingFsBlockDev", 0) = -1 ENOENT (No such file or directory)
-mknodat(AT_FDCWD, "/mnt/xfs/tmp/bbb/backingFsBlockDev", S_IFBLK|0600, makedev(7, 0)) = 0
-quotactl(Q_XSETQLIM|PRJQUOTA, "/mnt/xfs/tmp/bbb/backingFsBlockDev", 1, {version=1, flags=XFS_PROJ_QUOTA, fieldmask=0xc, id=1, blk_hardlimit=0, blk_softlimit=0, ino_hardlimit=0, ino_softlimit=0, bcount=0, icount=0, ...}) = 0
-...
-mkdirat(AT_FDCWD, "/mnt/xfs/tmp/bbb/ccc", 0755) = 0
-open("/mnt/xfs/tmp/bbb/ccc", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3
-fstat(3, {st_mode=S_IFDIR|0755, st_size=6, ...}) = 0
-ioctl(3, FS_IOC_FSGETXATTR, 0xc4201a95e4) = 0
-ioctl(3, FS_IOC_FSSETXATTR, 0xc4201a95e4) = 0
-
-quotactl(Q_XSETQLIM|PRJQUOTA, "/mnt/xfs/tmp/bbb/backingFsBlockDev", 2, {version=1, flags=XFS_PROJ_QUOTA, fieldmask=0xc, id=2, blk_hardlimit=2, blk_softlimit=2, ino_hardlimit=1024, ino_softlimit=1024, bcount=0, icount=0, ...}) = 0
-[pid  6833] ioctl(2, TCGETS, {B38400 opost isig icanon echo ...}) = 0
-
-
-// retrieving (ls)
-
-[pid  8609] quotactl(Q_XGETQUOTA|PRJQUOTA, "/mnt/xfs/tmp/ddd/backingFsBlockDev", 2, {version=1, flags=XFS_PROJ_QUOTA, fieldmask=0, id=2, blk_hardlimit=8, blk_softlimit=8, ino_hardlimit=0, ino_softlimit=0, bcount=8, icount=104, ...}) = 0
-
-
-```
+# Performance
+https://serverfault.com/questions/166748/performance-of-loopback-filesystems
+https://kernelnewbies.org/Linux_4.4#Faster_and_leaner_loop_device_with_Direct_I.2FO_and_Asynchronous_I.2FO_support
 
+https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6

Vagrantfile

@@ -0,0 +1,4 @@
+Vagrant.configure(2) do |config|
+  config.vm.box = "ubuntu/trusty64"
+  config.vm.provision :docker
+end

driver/driver.go

@@ -19,6 +19,7 @@ import (
 type Config struct {
 	StateDir    		string
 	DataDir    			string
+	MountDir    		string
 	DefaultSize    		string
 }
 
@@ -38,6 +39,7 @@ func NewDriver(cfg Config) (d Driver, err error) {
 	m, err := manager.New(manager.Config{
 		StateDir:	cfg.StateDir,
 		DataDir:	cfg.DataDir,
+		MountDir:	cfg.MountDir,
 	})
 	if err != nil {
 		err = errors.Wrapf(err,
@@ -144,14 +146,14 @@ func (d Driver) Get(req *v.GetRequest) (*v.GetResponse, error) {
 	resp.Volume = &v.Volume{
 		Name:       req.Name,
 		CreatedAt:  fmt.Sprintf(vol.CreatedAt.Format(time.RFC3339)),
-		Mountpoint: vol.EntrypointPath,
+		Mountpoint: vol.MountPointPath,
 		Status: map[string]interface{}{
 			"size": strconv.FormatUint(vol.SizeInBytes, 10),
 		},
 	}
 
 	logger.Debug().
-		Str("mountpoint", vol.EntrypointPath).
+		Str("mountpoint", vol.MountPointPath).
 		Msg("finished retrieving volume")
 	return resp, nil
 }
@@ -195,11 +197,11 @@ func (d Driver) Path(req *v.PathRequest) (*v.PathResponse, error) {
 	}
 
 	logger.Debug().
-		Str("path", vol.EntrypointPath).
+		Str("path", vol.MountPointPath).
 		Msg("finished retrieving volume path")
 
 	resp := new(v.PathResponse)
-	resp.Mountpoint = vol.EntrypointPath
+	resp.Mountpoint = vol.MountPointPath
 	return resp, nil
 }
 
@@ -231,7 +233,7 @@ func (d Driver) Mount(req *v.MountRequest) (*v.MountResponse, error) {
 func (d Driver) Unmount(req *v.UnmountRequest) (error) {
 	var logger = d.logger.With().
 		Str("log-id", shortid.MustGenerate()).
-		Str("method", "mount").
+		Str("method", "unmount").
 		Str("name", req.Name).
 		Str("id", req.ID).
 		Logger()

main.go

@@ -12,20 +12,24 @@ import (
 )
 
 const (
-	socketAddress = "/run/docker/plugins/dvl.sock"
+	socketAddress = "/run/docker/plugins/loop.sock"
 )
 
 type config struct {
 	StateDir			string `arg:"--state-dir,env:STATE_DIR,help:dir used to keep track of currently mounted volumes"`
 	DataDir				string `arg:"--data-dir,env:DATA_DIR,help:dir used to store actual volume data"`
+	MountDir			string `arg:"--mount-dir,env:MOUNT_DIR,help:dir used to create mount-points"`
 	DefaultSize			string `arg:"--default-size,env:DEFAULT_SIZE,help:default size for volumes created"`
 	Debug         		bool   `arg:"env:DEBUG,help:enable debug logs"`
 }
 
 var (
-	version = "master-dev"
 	logger         = zerolog.New(os.Stdout)
 	args           = &config{
+		StateDir: "/run/docker-volume-loopback",
+		DataDir: "/var/lib/docker-volume-loopback",
+		MountDir: "/mnt",
+		DefaultSize: "1G",
 		Debug:	false,
 	}
 )
@@ -34,7 +38,6 @@ func main() {
 	arg.MustParse(args)
 
 	logger.Info().
-		Str("version", version).
 		Str("socket-address", socketAddress).
 		Interface("args", args).
 		Msg("initializing plugin")
@@ -46,6 +49,7 @@ func main() {
 	d, err := driver.NewDriver(driver.Config{
 		StateDir:			args.StateDir,
 		DataDir:			args.DataDir,
+		MountDir:			args.MountDir,
 		DefaultSize:    	args.DefaultSize,
 	})
 	if err != nil {