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overlay: support additional image store on vfs
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Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
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@giuseppe
giuseppe committed Apr 24, 2024
1 parent ef0f37e commit 4791448
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Showing 2 changed files with 91 additions and 37 deletions.
99 changes: 70 additions & 29 deletions drivers/overlay/overlay.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ import (
graphdriver "github.com/containers/storage/drivers"
"github.com/containers/storage/drivers/overlayutils"
"github.com/containers/storage/drivers/quota"
"github.com/containers/storage/drivers/vfs"
"github.com/containers/storage/pkg/archive"
"github.com/containers/storage/pkg/chrootarchive"
"github.com/containers/storage/pkg/directory"
Expand Down Expand Up @@ -977,7 +978,7 @@ func (d *Driver) Create(id, parent string, opts *graphdriver.CreateOpts) (retErr
}

func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts, readOnly bool) (retErr error) {
dir, homedir, _ := d.dir2(id, readOnly)
dir, homedir, _, _ := d.dir2(id, false, false)

disableQuota := readOnly

Expand Down Expand Up @@ -1007,15 +1008,6 @@ func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts, readOnl
if err := idtools.MkdirAllAndChownNew(path.Dir(dir), 0o755, idPair); err != nil {
return err
}
if parent != "" {
parentBase := d.dir(parent)
st, err := system.Stat(filepath.Join(parentBase, "diff"))
if err != nil {
return err
}
rootUID = int(st.UID())
rootGID = int(st.GID())
}

if err := fileutils.Lexists(dir); err == nil {
logrus.Warnf("Trying to create a layer %#v while directory %q already exists; removing it first", id, dir)
Expand Down Expand Up @@ -1066,11 +1058,19 @@ func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts, readOnl
}

if parent != "" {
parentBase := d.dir(parent)
st, err := system.Stat(filepath.Join(parentBase, "diff"))
parentBase, _, singleLayer, _ := d.dir2(parent, false, true)
var d string
if singleLayer {
d = parentBase
} else {
d = filepath.Join(parentBase, "diff")
}
st, err := system.Stat(d)
if err != nil {
return err
}
rootUID = int(st.UID())
rootGID = int(st.GID())
perms = os.FileMode(st.Mode())
}

Expand Down Expand Up @@ -1142,13 +1142,17 @@ func (d *Driver) parseStorageOpt(storageOpt map[string]string, driver *Driver) e
}

func (d *Driver) getLower(parent string) (string, error) {
parentDir := d.dir(parent)
parentDir, _, singleLayer, _ := d.dir2(parent, false, true)

// Ensure parent exists
if err := fileutils.Lexists(parentDir); err != nil {
return "", err
}

if singleLayer {
return parent, nil
}

// Read Parent link fileA
parentLink, err := os.ReadFile(path.Join(parentDir, "link"))
if err != nil {
Expand All @@ -1175,7 +1179,7 @@ func (d *Driver) getLower(parent string) (string, error) {
}

func (d *Driver) dir(id string) string {
p, _, _ := d.dir2(id, false)
p, _, _, _ := d.dir2(id, false, false)
return p
}

Expand All @@ -1187,7 +1191,15 @@ func (d *Driver) getAllImageStores() []string {
return additionalImageStores
}

func (d *Driver) dir2(id string, useImageStore bool) (string, string, bool) {
// dir2 returns the directory path and home directory path associated with the given layer ID.
// It also returns two boolean values indicating if the store is using the VFS graph driver, and
// whether the directory is found in an image store.
//
// - string: The directory path for the layer.
// - string: The storage home directory path.
// - bool: A boolean indicating whether the store is using VFS, thus doesn't require stacking of layers.
// - bool: A boolean indicating whether the directory is found in an additional image store.
func (d *Driver) dir2(id string, useImageStore, useVFS bool) (string, string, bool, bool) {
var homedir string

if useImageStore && d.imageStore != "" {
Expand All @@ -1196,18 +1208,27 @@ func (d *Driver) dir2(id string, useImageStore bool) (string, string, bool) {
homedir = d.home
}

newpath := path.Join(homedir, id)
primaryPath := path.Join(homedir, id)
if err := fileutils.Exists(primaryPath); err == nil {
return primaryPath, homedir, false, false
}

if err := fileutils.Exists(newpath); err != nil {
for _, p := range d.getAllImageStores() {
l := path.Join(p, d.name, id)
err = fileutils.Exists(l)
if err == nil {
return l, homedir, true
allImageStores := d.getAllImageStores()
for _, p := range allImageStores {
l := path.Join(p, d.name, id)
if err := fileutils.Exists(l); err == nil {
return l, homedir, false, true
}
if useVFS {
l = path.Join(p, vfs.Name, "dir", id)
if err := fileutils.Exists(l); err == nil {
return l, homedir, true, true
}
}
}
return newpath, homedir, false

// It does not exist, return where to create it.
return primaryPath, homedir, false, false
}

func (d *Driver) getLowerDirs(id string) ([]string, error) {
Expand Down Expand Up @@ -1417,7 +1438,7 @@ func (d *Driver) Get(id string, options graphdriver.MountOpts) (string, error) {
}

func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountOpts) (_ string, retErr error) {
dir, _, inAdditionalStore := d.dir2(id, false)
dir, _, _, inAdditionalStore := d.dir2(id, false, true)
if err := fileutils.Exists(dir); err != nil {
return "", err
}
Expand Down Expand Up @@ -1529,6 +1550,9 @@ func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountO
composeFsLayersDir := filepath.Join(dir, "composefs-layers")
maybeAddComposefsMount := func(lowerID string, i int, readWrite bool) (string, error) {
composefsBlob := d.getComposefsData(lowerID)
if composefsBlob == "" {
return "", nil
}
if err := fileutils.Exists(composefsBlob); err != nil {
if os.IsNotExist(err) {
return "", nil
Expand Down Expand Up @@ -1577,7 +1601,8 @@ func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountO
lower := ""
newpath := path.Join(d.home, l)
if st, err := os.Stat(newpath); err != nil {
for _, p := range d.getAllImageStores() {
allImageStores := d.getAllImageStores()
for _, p := range allImageStores {
lower = path.Join(p, d.name, l)
if st2, err2 := os.Stat(lower); err2 == nil {
if !permsKnown {
Expand All @@ -1586,6 +1611,15 @@ func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountO
}
break
}
// now try in the vfs store
lower = path.Join(p, vfs.Name, "dir", l)
if st2, err2 := os.Stat(lower); err2 == nil {
if !permsKnown {
perms = os.FileMode(st2.Mode())
permsKnown = true
}
break
}
lower = ""
}
// if it is a "not found" error, that means the symlinks were lost in a sudden reboot
Expand All @@ -1610,7 +1644,10 @@ func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountO

linkContent, err := os.Readlink(lower)
if err != nil {
return "", err
if !errors.Is(err, unix.EINVAL) { // Not a symlink, a raw path
return "", err
}
linkContent = lower
}
lowerID := filepath.Base(filepath.Dir(linkContent))
composefsMount, err := maybeAddComposefsMount(lowerID, i+1, readWrite)
Expand Down Expand Up @@ -1835,10 +1872,14 @@ func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountO

// Put unmounts the mount path created for the give id.
func (d *Driver) Put(id string) error {
dir, _, inAdditionalStore := d.dir2(id, false)
dir, _, singleLayer, inAdditionalStore := d.dir2(id, false, true)
if err := fileutils.Exists(dir); err != nil {
return err
}
if singleLayer {
return nil
}

mountpoint := path.Join(dir, "merged")
if count := d.ctr.Decrement(mountpoint); count > 0 {
return nil
Expand Down Expand Up @@ -2005,7 +2046,7 @@ func (g *overlayFileGetter) Close() error {
}

func (d *Driver) getStagingDir(id string) string {
_, homedir, _ := d.dir2(id, d.imageStore != "")
_, homedir, _, _ := d.dir2(id, d.imageStore != "", false)
return filepath.Join(homedir, stagingDir)
}

Expand Down Expand Up @@ -2283,7 +2324,7 @@ func (d *Driver) Changes(id string, idMappings *idtools.IDMappings, parent strin

// AdditionalImageStores returns additional image stores supported by the driver
func (d *Driver) AdditionalImageStores() ([]string, []string) {
return d.options.imageStores, []string{d.name}
return d.options.imageStores, []string{d.name, vfs.Name}
}

// UpdateLayerIDMap updates ID mappings in a from matching the ones specified
Expand Down
29 changes: 21 additions & 8 deletions tests/stores.bats
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,14 +2,8 @@

load helpers

@test "additional-stores" {
case "$STORAGE_DRIVER" in
overlay*|vfs)
;;
*)
skip "not supported by driver $STORAGE_DRIVER"
;;
esac
additional_store_test() {
export STORAGE_DRIVER=$1
# Initialize a store somewhere that we'll later use as a read-only store.
storage --graph ${TESTDIR}/ro-root --run ${TESTDIR}/ro-runroot layers
# Fail this test if we can't initialize the driver with the option.
Expand Down Expand Up @@ -59,6 +53,8 @@ load helpers
# We no longer need to use the read-only root as a writeable location, so shut it down.
storage --graph ${TESTDIR}/ro-root --run ${TESTDIR}/ro-runroot shutdown

export STORAGE_DRIVER=$2

# Create a third layer based on the second one.
run storage --storage-opt ${STORAGE_DRIVER}.imagestore=${TESTDIR}/ro-root --debug=false create-layer "$midlayer"
[ "$status" -eq 0 ]
Expand Down Expand Up @@ -151,3 +147,20 @@ load helpers
[ "$output" != "" ]
! [[ "$output" =~ "Read Only: true" ]]
}

@test "additional-stores" {
case "$STORAGE_DRIVER" in
overlay*|vfs)
;;
*)
skip "not supported by driver $STORAGE_DRIVER"
;;
esac

additional_store_test $STORAGE_DRIVER $STORAGE_DRIVER

# if the graphdriver is overlay, also test overlay using an additional store on vfs
if test "$STORAGE_DRIVER" == "overlay" -a "$STORAGE_OPTION" == ""; then
additional_store_test vfs $STORAGE_DRIVER
fi
}

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