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surgeon.go
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surgeon.go
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package surgeon
import (
"fmt"
"os"
"go.etcd.io/bbolt/internal/guts_cli"
)
func CopyPage(path string, srcPage guts_cli.Pgid, target guts_cli.Pgid) error {
p1, d1, err1 := guts_cli.ReadPage(path, uint64(srcPage))
if err1 != nil {
return err1
}
p1.SetId(target)
return WritePage(path, d1)
}
func WritePage(path string, pageBuf []byte) error {
page := guts_cli.LoadPage(pageBuf)
pageSize, _, err := guts_cli.ReadPageAndHWMSize(path)
if err != nil {
return err
}
if pageSize != uint64(len(pageBuf)) {
return fmt.Errorf("WritePage: len(buf)=%d != pageSize=%d", len(pageBuf), pageSize)
}
f, err := os.OpenFile(path, os.O_WRONLY, 0)
if err != nil {
return err
}
defer f.Close()
_, err = f.WriteAt(pageBuf, int64(page.Id())*int64(pageSize))
return err
}
// RevertMetaPage replaces the newer metadata page with the older.
// It usually means that one transaction is being lost. But frequently
// data corruption happens on the last transaction pages and the
// previous state is consistent.
func RevertMetaPage(path string) error {
_, activeMetaPage, err := guts_cli.GetRootPage(path)
if err != nil {
return err
}
if activeMetaPage == 0 {
return CopyPage(path, 1, 0)
} else {
return CopyPage(path, 0, 1)
}
}