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authorJakob Unterwurzacher2018-07-01 19:14:00 +0200
committerJakob Unterwurzacher2018-07-01 21:48:51 +0200
commit2d68b06f9dab66b2a0a6c29c8d5450e2b1d43fae (patch)
tree77f1b55fca2cf58595b33e8d062cf6437f85f283
parente951043084937c42421debf457e33b3db3b5bac4 (diff)
fsck: handle sparse files efficiently, fix xfstests generic/285
If we encounter a 128KB block of zeros, try to skip to the next data section by calling File.SeekData(). This fixes xfstests generic/285, which creates a 17TB sparse file, and runs fsck afterwards. Without this optimization, fsck would take ages.
-rw-r--r--fsck.go11
-rw-r--r--tests/fsck/fsck_test.go40
2 files changed, 51 insertions, 0 deletions
diff --git a/fsck.go b/fsck.go
index 37157cb..59bb2f0 100644
--- a/fsck.go
+++ b/fsck.go
@@ -1,6 +1,7 @@
package main
import (
+ "bytes"
"fmt"
"os"
"path/filepath"
@@ -115,6 +116,7 @@ func (ck *fsckObj) file(path string) {
return
}
defer f.Release()
+ allZero := make([]byte, fuse.MAX_KERNEL_WRITE)
buf := make([]byte, fuse.MAX_KERNEL_WRITE)
var off int64
// Read() through the whole file and catch transparently mitigated corruptions
@@ -132,6 +134,15 @@ func (ck *fsckObj) file(path string) {
return
}
off += int64(result.Size())
+ // If we seem to be in the middle of a file hole, try to skip to the next
+ // data section.
+ if bytes.Equal(buf, allZero) {
+ f2 := f.(*fusefrontend.File)
+ nextOff, err := f2.SeekData(off)
+ if err == nil {
+ off = nextOff
+ }
+ }
}
}
diff --git a/tests/fsck/fsck_test.go b/tests/fsck/fsck_test.go
index 8e73cf7..5ece6cd 100644
--- a/tests/fsck/fsck_test.go
+++ b/tests/fsck/fsck_test.go
@@ -4,8 +4,10 @@ import (
"encoding/base64"
"os"
"os/exec"
+ "runtime"
"strings"
"testing"
+ "time"
"github.com/pkg/xattr"
@@ -84,3 +86,41 @@ func TestExampleFses(t *testing.T) {
}
}
}
+
+// TestTerabyteFile verifies that fsck does something intelligent when it hits
+// a 1-terabyte sparse file (trying to read the whole file is not intelligent).
+func TestTerabyteFile(t *testing.T) {
+ if runtime.GOOS != "linux" {
+ t.Skipf("Only linux supports SEEK_DATA")
+ }
+ cDir := test_helpers.InitFS(t)
+ pDir := cDir + ".mnt"
+ test_helpers.MountOrFatal(t, cDir, pDir, "-extpass", "echo test")
+ defer test_helpers.UnmountErr(pDir)
+ exabyteFile := pDir + "/exabyteFile"
+ fd, err := os.Create(exabyteFile)
+ if err != nil {
+ t.Fatal(err)
+ }
+ defer fd.Close()
+ var oneTiB int64 = 1024 * 1024 * 1024 * 1024
+ _, err = fd.WriteAt([]byte("foobar"), oneTiB)
+ if err != nil {
+ t.Fatal(err)
+ }
+ fi, err := fd.Stat()
+ if err != nil {
+ t.Fatal(err)
+ }
+ t.Logf("size=%d, running fsck", fi.Size())
+ cmd := exec.Command(test_helpers.GocryptfsBinary, "-fsck", "-extpass", "echo test", cDir)
+ cmd.Stderr = os.Stderr
+ cmd.Stdout = os.Stdout
+ cmd.Start()
+ timer := time.AfterFunc(10*time.Second, func() {
+ cmd.Process.Kill()
+ t.Fatalf("timeout")
+ })
+ cmd.Wait()
+ timer.Stop()
+}