base: docker-moby: patch to fsync layer metadata

mike-sul · ricardosalveti · commit 86d02315bd73 · 2021-10-18T14:14:57.000-03:00
Fsync `link` and `lower` layer files just after write to make sure their
content is stored on a persistent storage. It helps to overcome
the issue that occurs when image layers download/extraction is
interrupted by a power cut.
Docker daemon can recover if the interrupted layer is "broken",
but it cannot recover if there are two or more lower to the interrupted
layers are "broken". The given fix makes sure that the lower layers that
are fully downloaded and extracted are consistent even if the current
top layer is broken.

Signed-off-by: Mike Sul &lt;mike.sul@foundries.io&gt;
diff --git a/meta-lmp-base/recipes-containers/docker/docker-moby.bb b/meta-lmp-base/recipes-containers/docker/docker-moby.bb
@@ -50,6 +50,7 @@ SRC_URI = "\
 	file://increase_containerd_timeouts.patch \
 	file://dockerd-daemon-reload-image-store-on-a-hup-signal.patch \
 	file://0001-registry-increase-TLS-and-connection-timeouts.patch \
+	file://0001-overlay2-fsync-layer-metadata-files.patch \
 	"
 
 require recipes-containers/docker/docker.inc
diff --git a/meta-lmp-base/recipes-containers/docker/docker-moby/0001-overlay2-fsync-layer-metadata-files.patch b/meta-lmp-base/recipes-containers/docker/docker-moby/0001-overlay2-fsync-layer-metadata-files.patch
@@ -0,0 +1,75 @@
+From 14cb4453d05cd2a66efecbd1288bd2c7a7ff19a6 Mon Sep 17 00:00:00 2001
+From: Mike Sul <mike.sul@foundries.io>
+Date: Mon, 18 Oct 2021 12:19:14 +0300
+Subject: [PATCH] overlay2: fsync layer metadata files
+
+Fsync `link` and `lower` layer files just after write to make sure their
+content is actually stored on a persistent storage. It helps to overcome
+the issue that occurs when image layers download/extraction is
+interrupted by a power cut.
+Docker daemon can recover if there the interrupted layer is "broken",
+but it cannot recover if there are two or more lower to the interrupted
+layers are "broken". The given fix makes sure that the lower layers that
+are fully downloaded and extracted are consistent even if the current
+top layer is broken.
+
+Signed-off-by: Mike Sul <mike.sul@foundries.io>
+---
+ daemon/graphdriver/overlay2/overlay.go | 30 ++++++++++++++++++++++++++
+ 1 file changed, 30 insertions(+)
+
+diff --git a/src/import/daemon/graphdriver/overlay2/overlay.go b/src/import/daemon/graphdriver/overlay2/overlay.go
+index 36a921a018..6127f64936 100644
+--- a/src/import/daemon/graphdriver/overlay2/overlay.go
++++ b/src/import/daemon/graphdriver/overlay2/overlay.go
+@@ -387,6 +387,7 @@ func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts) (retErr
+ 	if err := ioutil.WriteFile(path.Join(dir, "link"), []byte(lid), 0644); err != nil {
+ 		return err
+ 	}
++	fsync(path.Join(dir, "link"))
+ 
+ 	// if no parent directory, done
+ 	if parent == "" {
+@@ -409,6 +410,7 @@ func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts) (retErr
+ 		if err := ioutil.WriteFile(path.Join(dir, lowerFile), []byte(lower), 0666); err != nil {
+ 			return err
+ 		}
++		fsync(path.Join(dir, lowerFile))
+ 	}
+ 
+ 	return nil
+@@ -736,3 +738,31 @@ func (d *Driver) Diff(id, parent string) (io.ReadCloser, error) {
+ func (d *Driver) Changes(id, parent string) ([]archive.Change, error) {
+ 	return d.naiveDiff.Changes(id, parent)
+ }
++
++
++// Foundries.io patch to fsync changes
++func fsync(path string) {
++	f, err := os.Open(path)
++	if err != nil {
++		logger.Warnf(">>> FIO: failed to open file for fsyncing; file: %s, err: %s", path, err.Error())
++		return
++	}
++	if f == nil {
++		logger.Warnf(">>> FIO: failed to open file for fsyncing; file: %s, err: nil file descriptor", path)
++		return
++	}
++
++	defer func() {
++		err := f.Close()
++		if err != nil {
++			logger.Warnf(">>> FIO: failed to close a file opened for fsyncing; file: %s, err: %s", path, err.Error())
++		}
++	}()
++
++	err = f.Sync()
++	if err == nil {
++		logger.Infof(">>> FIO: fsync %s", path)
++	} else {
++		logger.Infof(">>> FIO: failed to fsync %s, err: %s", path, err.Error())
++	}
++}
+-- 
+2.17.1
+

Original file line number	Diff line number	Diff line change
`@@ -50,6 +50,7 @@ SRC_URI = "\`
`50`	`50`	`file://increase_containerd_timeouts.patch \`
`51`	`51`	`file://dockerd-daemon-reload-image-store-on-a-hup-signal.patch \`
`52`	`52`	`file://0001-registry-increase-TLS-and-connection-timeouts.patch \`
	`53`	`+ file://0001-overlay2-fsync-layer-metadata-files.patch \`
`53`	`54`	`"`
`54`	`55`
`55`	`56`	`require recipes-containers/docker/docker.inc`