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@@ -0,0 +1,90 @@
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+package worker
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+
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+import (
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+ "fmt"
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+ "os"
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+ "path/filepath"
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+
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+ "github.com/dennwc/btrfs"
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+)
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+
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+type btrfsSnapshotHook struct {
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+ provider mirrorProvider
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+ mirrorSnapshotPath string
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+}
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+
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+// the user who runs the jobs (typically `tunasync`) should be granted the permission to run btrfs commands
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+// TODO: check if the filesystem is Btrfs
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+func newBtrfsSnapshotHook(provider mirrorProvider, snapshotPath string, mirror mirrorConfig) *btrfsSnapshotHook {
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+ mirrorSnapshotPath := mirror.SnapshotPath
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+ if mirrorSnapshotPath == "" {
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+ mirrorSnapshotPath = filepath.Join(snapshotPath, provider.Name())
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+ }
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+ return &btrfsSnapshotHook{
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+ provider: provider,
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+ mirrorSnapshotPath: mirrorSnapshotPath,
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+ }
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+}
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+
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+// check if path `snapshotPath/providerName` exists
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+// Case 1: Not exists => create a new subvolume
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+// Case 2: Exists as a subvolume => nothing to do
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+// Case 3: Exists as a directory => error detected
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+func (h *btrfsSnapshotHook) preJob() error {
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+ path := h.provider.WorkingDir()
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+ if _, err := os.Stat(path); os.IsNotExist(err) {
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+ // create subvolume
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+ err := btrfs.CreateSubVolume(path)
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+ if err != nil {
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+ logger.Errorf("failed to create Btrfs subvolume %s: %s", path, err.Error())
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+ return err
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+ }
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+ logger.Noticef("created new Btrfs subvolume %s", path)
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+ } else {
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+ if is, err := btrfs.IsSubVolume(path); err != nil {
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+ return err
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+ } else if !is {
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+ return fmt.Errorf("path %s exists but isn't a Btrfs subvolume", path)
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+ }
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+ }
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+ return nil
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+}
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+
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+func (h *btrfsSnapshotHook) preExec() error {
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+ return nil
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+}
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+
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+func (h *btrfsSnapshotHook) postExec() error {
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+ return nil
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+}
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+
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+// delete old snapshot if exists, then create a new snapshot
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+func (h *btrfsSnapshotHook) postSuccess() error {
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+ if _, err := os.Stat(h.mirrorSnapshotPath); !os.IsNotExist(err) {
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+ isSubVol, err := btrfs.IsSubVolume(h.mirrorSnapshotPath)
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+ if err != nil {
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+ return err
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+ } else if !isSubVol {
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+ return fmt.Errorf("path %s exists and isn't a Btrfs snapshot", h.mirrorSnapshotPath)
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+ }
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+ // is old snapshot => delete it
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+ if err := btrfs.DeleteSubVolume(h.mirrorSnapshotPath); err != nil {
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+ logger.Errorf("failed to delete old Btrfs snapshot %s", h.mirrorSnapshotPath)
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+ return err
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+ }
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+ logger.Noticef("deleted old snapshot %s", h.mirrorSnapshotPath)
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+ }
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+ // create a new writable snapshot
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+ // (the snapshot is writable so that it can be deleted easily)
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+ if err := btrfs.SnapshotSubVolume(h.provider.WorkingDir(), h.mirrorSnapshotPath, false); err != nil {
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+ logger.Errorf("failed to create new Btrfs snapshot %s", h.mirrorSnapshotPath)
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+ return err
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+ }
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+ logger.Noticef("created new Btrfs snapshot %s", h.mirrorSnapshotPath)
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+ return nil
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+}
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+
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+// keep the old snapshot => nothing to do
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+func (h *btrfsSnapshotHook) postFail() error {
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+ return nil
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+}
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