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Remove unused passive symlinks for loopdevice
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Current loopdevice snapshotter does not require anymore
having symlinks to list passive snapshots. Current grub2
configuration configures the passive snapshot path based on
the snapshot ID.

Signed-off-by: David Cassany <dcassany@suse.com>
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@davidcassany
davidcassany committed Feb 19, 2024
1 parent 2d01d9a commit 1733a87
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Showing 3 changed files with 53 additions and 88 deletions.
1 change: 0 additions & 1 deletion pkg/constants/constants.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -176,7 +176,6 @@ const (
LoopDeviceSnapshotterType = "loopdevice"
BtrfsSnapshotterType = "btrfs"
ActiveSnapshot = "active"
PassiveSnapshot = "passive_%d"

// Legacy paths
LegacyImagesPath = "cOS"
Expand Down
7 changes: 0 additions & 7 deletions pkg/mocks/utils.go
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Original file line number Diff line number Diff line change
Expand Up @@ -54,12 +54,5 @@ func FakeLoopDeviceSnapshotsStatus(fs v1.FS, rootDir string, snapsCount int) err
if err != nil {
return err
}
for i = 1; i <= snapsCount-1; i++ {
snapshotFile = filepath.Join("..", strconv.Itoa(i), "snapshot.img")
err = fs.Symlink(snapshotFile, filepath.Join(passivesPath, fmt.Sprintf(constants.PassiveSnapshot, i)))
if err != nil {
return err
}
}
return err
}
133 changes: 53 additions & 80 deletions pkg/snapshotter/loopdevice.go
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Original file line number Diff line number Diff line change
Expand Up @@ -38,7 +38,6 @@ const (
loopDeviceImgName = "snapshot.img"
loopDeviceWorkDir = "snapshot.workDir"
loopDeviceLabelPattern = "EL_SNAP%d"
loopDevicePassivePath = loopDeviceSnapsPath + "/passives"
)

var _ v1.Snapshotter = (*LoopDevice)(nil)
Expand Down Expand Up @@ -218,18 +217,19 @@ func (l *LoopDevice) CloseTransactionOnError(snapshot *v1.Snapshot) error {
// CloseTransaction closes the transaction for the given snapshot. This is the responsible of setting new active and
// passive snapshots.
func (l *LoopDevice) CloseTransaction(snapshot *v1.Snapshot) (err error) {
var linkDst, newPassive, activeSnap string
var linkDst, activeSnap string

if !snapshot.InProgress {
l.cfg.Logger.Debugf("No transaction to close for snapshot %d workdir", snapshot.ID)
return fmt.Errorf("given snapshot is not in progress")
}
defer func() {
if err != nil {
_ = l.CloseTransactionOnError(snapshot)
}
}()

if !snapshot.InProgress {
l.cfg.Logger.Debugf("No transaction to close for snapshot %d workdir", snapshot.ID)
return fmt.Errorf("given snapshot is not in progress")
}

l.cfg.Logger.Infof("Closing transaction for snapshot %d workdir", snapshot.ID)
l.cfg.Logger.Debugf("Unmount %s", snapshot.MountPoint)
err = l.cfg.Mounter.Unmount(snapshot.MountPoint)
Expand All @@ -249,19 +249,6 @@ func (l *LoopDevice) CloseTransaction(snapshot *v1.Snapshot) (err error) {
return err
}

// Create fallback link for current active snapshot
newPassive = filepath.Join(l.rootDir, loopDevicePassivePath, fmt.Sprintf(constants.PassiveSnapshot, l.activeSnapshotID))
if l.activeSnapshotID > 0 {
linkDst = fmt.Sprintf("../%d/%s", l.activeSnapshotID, loopDeviceImgName)
l.cfg.Logger.Debugf("creating symlink %s to %s", newPassive, linkDst)
err = l.cfg.Fs.Symlink(linkDst, newPassive)
if err != nil {
l.cfg.Logger.Errorf("failed creating the new passive link: %v", err)
return err
}
l.cfg.Logger.Infof("New passive snapshot fallback from active (%d) created", l.activeSnapshotID)
}

// Remove old symlink and create a new one
activeSnap = filepath.Join(l.rootDir, loopDeviceSnapsPath, constants.ActiveSnapshot)
linkDst = fmt.Sprintf("%d/%s", snapshot.ID, loopDeviceImgName)
Expand All @@ -270,7 +257,6 @@ func (l *LoopDevice) CloseTransaction(snapshot *v1.Snapshot) (err error) {
err = l.cfg.Fs.Symlink(linkDst, activeSnap)
if err != nil {
l.cfg.Logger.Errorf("failed default snapshot image for snapshot %d: %v", snapshot.ID, err)
_ = l.cfg.Fs.Remove(newPassive)
sErr := l.cfg.Fs.Symlink(fmt.Sprintf("%d/%s", l.activeSnapshotID, loopDeviceImgName), activeSnap)
if sErr != nil {
l.cfg.Logger.Warnf("could not restore previous active link")
Expand All @@ -290,7 +276,6 @@ func (l *LoopDevice) CloseTransaction(snapshot *v1.Snapshot) (err error) {
// DeleteSnapshot deletes the snapshot of the given ID. It cannot delete an snapshot that is actually booted.
func (l *LoopDevice) DeleteSnapshot(id int) error {
var err error
var snapLink string

l.cfg.Logger.Infof("Deleting snapshot %d", id)
inUse, err := l.isSnapshotInUse(id)
Expand Down Expand Up @@ -321,15 +306,12 @@ func (l *LoopDevice) DeleteSnapshot(id int) error {
}

if l.activeSnapshotID == id {
snapLink = filepath.Join(l.rootDir, loopDeviceSnapsPath, constants.ActiveSnapshot)
} else {
snapLink = filepath.Join(l.rootDir, loopDevicePassivePath, fmt.Sprintf(constants.PassiveSnapshot, id))
}

err = l.cfg.Fs.Remove(snapLink)
if err != nil {
l.cfg.Logger.Errorf("failed removing snapshot link %s: %v", snapLink, err)
return err
snapLink := filepath.Join(l.rootDir, loopDeviceSnapsPath, constants.ActiveSnapshot)
err = l.cfg.Fs.Remove(snapLink)
if err != nil {
l.cfg.Logger.Errorf("failed removing snapshot link %s: %v", snapLink, err)
return err
}
}

snapDir := filepath.Join(l.rootDir, loopDeviceSnapsPath, strconv.Itoa(id))
Expand All @@ -344,20 +326,30 @@ func (l *LoopDevice) DeleteSnapshot(id int) error {
func (l *LoopDevice) GetSnapshots() ([]int, error) {
var ids []int

ids, err := l.getPassiveSnapshots()
if err != nil {
return nil, err
}

id, err := l.getActiveSnapshot()
if err != nil {
return nil, err
}

if id > 0 {
return append(ids, id), nil
snapsPath := filepath.Join(l.rootDir, loopDeviceSnapsPath)
r := regexp.MustCompile(`^\d+$`)
if ok, _ := utils.Exists(l.cfg.Fs, snapsPath); ok {
dirs, err := l.cfg.Fs.ReadDir(snapsPath)
if err != nil {
l.cfg.Logger.Errorf("failed reading %s contents", snapsPath)
return ids, err
}
for _, dir := range dirs {
// Find snapshots based numeric directory names
if !r.MatchString(dir.Name()) {
continue
}
id, err := strconv.Atoi(dir.Name())
if err != nil {
continue
}
ids = append(ids, id)
}
l.cfg.Logger.Debugf("Found snapshots: %v", ids)
return ids, nil
}
return ids, nil
l.cfg.Logger.Errorf("path %s does not exist", snapsPath)
return ids, fmt.Errorf("cannot determine snapshots, initate snapshotter first")
}

// SnapshotImageToSource converts the given snapshot into an ImageSource. This is useful to deploy a system
Expand Down Expand Up @@ -518,38 +510,27 @@ func (l *LoopDevice) setBootloader() error {

// getPassiveSnapshots returns a list of available passive snapshots
func (l *LoopDevice) getPassiveSnapshots() ([]int, error) {
var ids []int
allIDs, err := l.GetSnapshots()
if err != nil {
l.cfg.Logger.Errorf("failed processing available snapshots list: %s", err.Error())
return nil, err
}

snapsPath := filepath.Join(l.rootDir, loopDevicePassivePath)
r := regexp.MustCompile(`passive_(\d+)`)
if ok, _ := utils.Exists(l.cfg.Fs, snapsPath); ok {
links, err := l.cfg.Fs.ReadDir(snapsPath)
if err != nil {
l.cfg.Logger.Errorf("failed reading %s contents", snapsPath)
return ids, err
}
for _, link := range links {
// Find snapshots based numeric directory names
if !r.MatchString(link.Name()) {
continue
}
matches := r.FindStringSubmatch(link.Name())
id, err := strconv.Atoi(matches[1])
if err != nil {
continue
}
linkPath := filepath.Join(snapsPath, link.Name())
if exists, _ := utils.Exists(l.cfg.Fs, linkPath); exists {
ids = append(ids, id)
} else {
l.cfg.Logger.Warnf("image for snapshot %d doesn't exist", id)
}
activeID, err := l.getActiveSnapshot()
if err != nil {
l.cfg.Logger.Errorf("failed processing current active snapshot: %s", err.Error())
return nil, err
}

passiveIDs := []int{}
for _, id := range allIDs {
if id == activeID {
continue
}
l.cfg.Logger.Debugf("Passive snapshots: %v", ids)
return ids, nil
passiveIDs = append(passiveIDs, id)
}
l.cfg.Logger.Errorf("path %s does not exist", snapsPath)
return ids, fmt.Errorf("cannot determine passive snapshots, initate snapshotter first")

return passiveIDs, nil
}

// legacyImageToSnapshot is method to migrate existing legacy passive.img or active.img as a new loop device snapshot
Expand All @@ -573,14 +554,6 @@ func (l *LoopDevice) legacyImageToSnapsot(image string) error {
l.cfg.Logger.Errorf("failed copying legacy image as snapshot: %v", err)
return err
}

passiveLink := fmt.Sprintf("../%d/%s", id, loopDeviceImgName)
newPassive := filepath.Join(l.rootDir, loopDevicePassivePath, fmt.Sprintf(constants.PassiveSnapshot, id))
err = l.cfg.Fs.Symlink(passiveLink, newPassive)
if err != nil {
l.cfg.Logger.Errorf("failed creating the passive link for legacy images: %v", err)
return err
}
}
return nil
}
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