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authorJakob Unterwurzacher2016-09-21 21:25:55 +0200
committerJakob Unterwurzacher2016-09-25 16:43:17 +0200
commitd76e7aadb48e5efd6af6ad42e9146f65f8e89fb8 (patch)
treea3ac9bbd25c01988ecd4170beddb268c3837a737 /internal
parent5f726aaa9d95be30ecfcb61637df3ccc133bf2ea (diff)
reverse: use dynamic inode numbers
...with stable mappings for hard-linked files.
Diffstat (limited to 'internal')
-rw-r--r--internal/fusefrontend_reverse/ino_map.go24
-rw-r--r--internal/fusefrontend_reverse/rfs.go59
2 files changed, 78 insertions, 5 deletions
diff --git a/internal/fusefrontend_reverse/ino_map.go b/internal/fusefrontend_reverse/ino_map.go
new file mode 100644
index 0000000..5217732
--- /dev/null
+++ b/internal/fusefrontend_reverse/ino_map.go
@@ -0,0 +1,24 @@
+package fusefrontend_reverse
+
+import (
+ "sync/atomic"
+)
+
+func NewInoGen() *inoGenT {
+ var ino uint64 = 1
+ return &inoGenT{&ino}
+}
+
+type inoGenT struct {
+ ino *uint64
+}
+
+// Get the next inode counter value
+func (i *inoGenT) next() uint64 {
+ return atomic.AddUint64(i.ino, 1)
+}
+
+type devIno struct {
+ dev uint64
+ ino uint64
+}
diff --git a/internal/fusefrontend_reverse/rfs.go b/internal/fusefrontend_reverse/rfs.go
index 4b04b86..4f516fd 100644
--- a/internal/fusefrontend_reverse/rfs.go
+++ b/internal/fusefrontend_reverse/rfs.go
@@ -4,6 +4,7 @@ import (
"fmt"
"os"
"path/filepath"
+ "sync"
"syscall"
"github.com/hanwen/go-fuse/fuse"
@@ -32,6 +33,12 @@ type reverseFS struct {
nameTransform *nametransform.NameTransform
// Content encryption helper
contentEnc *contentenc.ContentEnc
+ // Inode number generator
+ inoGen *inoGenT
+ // Maps backing files device+inode pairs to user-facing unique inode numbers
+ inoMap map[devIno]uint64
+ // Protects map access
+ inoMapLock sync.Mutex
}
// Encrypted FUSE overlay filesystem
@@ -47,6 +54,8 @@ func NewFS(args fusefrontend.Args) *reverseFS {
args: args,
nameTransform: nameTransform,
contentEnc: contentEnc,
+ inoGen: NewInoGen(),
+ inoMap: map[devIno]uint64{},
}
}
@@ -85,11 +94,11 @@ func (rfs *reverseFS) dirIVAttr(relPath string, context *fuse.Context) (*fuse.At
fmt.Printf("not exec")
return nil, fuse.EPERM
}
- // All good. Let's fake the file.
- // We use the inode number of the parent dir (can this cause problems?).
+ // All good. Let's fake the file. We use the timestamps from the parent dir.
a.Mode = DirIVMode
a.Size = nametransform.DirIVLen
a.Nlink = 1
+ a.Ino = rfs.inoGen.next()
return a, fuse.OK
}
@@ -99,10 +108,45 @@ func isDirIV(relPath string) bool {
return filepath.Base(relPath) == nametransform.DirIVFilename
}
+func (rfs *reverseFS) inoAwareStat(relPlainPath string) (*fuse.Attr, fuse.Status) {
+ absPath, err := rfs.abs(relPlainPath, nil)
+ if err != nil {
+ return nil, fuse.ToStatus(err)
+ }
+ var fi os.FileInfo
+ if relPlainPath == "" {
+ // Look through symlinks for the root dir
+ fi, err = os.Stat(absPath)
+ } else {
+ fi, err = os.Lstat(absPath)
+ }
+ if err != nil {
+ return nil, fuse.ToStatus(err)
+ }
+ st := fi.Sys().(*syscall.Stat_t)
+ // The file has hard links. We have to give it a stable inode number so
+ // tar or rsync can find them.
+ if fi.Mode().IsRegular() && st.Nlink > 1 {
+ di := devIno{st.Dev, st.Ino}
+ rfs.inoMapLock.Lock()
+ stableIno := rfs.inoMap[di]
+ if stableIno == 0 {
+ rfs.inoMap[di] = rfs.inoGen.next()
+ }
+ rfs.inoMapLock.Unlock()
+ st.Ino = stableIno
+ } else {
+ st.Ino = rfs.inoGen.next()
+ }
+ a := &fuse.Attr{}
+ a.FromStat(st)
+ return a, fuse.OK
+}
+
// GetAttr - FUSE call
func (rfs *reverseFS) GetAttr(relPath string, context *fuse.Context) (*fuse.Attr, fuse.Status) {
if relPath == configfile.ConfDefaultName {
- return rfs.loopbackfs.GetAttr(configfile.ConfReverseName, context)
+ return rfs.inoAwareStat(configfile.ConfReverseName)
}
if isDirIV(relPath) {
return rfs.dirIVAttr(relPath, context)
@@ -110,11 +154,11 @@ func (rfs *reverseFS) GetAttr(relPath string, context *fuse.Context) (*fuse.Attr
if rfs.isFiltered(relPath) {
return nil, fuse.EPERM
}
- relPath, err := rfs.decryptPath(relPath)
+ cPath, err := rfs.decryptPath(relPath)
if err != nil {
return nil, fuse.ToStatus(err)
}
- a, status := rfs.loopbackfs.GetAttr(relPath, context)
+ a, status := rfs.inoAwareStat(cPath)
if !status.Ok() {
return nil, status
}
@@ -189,3 +233,8 @@ func (rfs *reverseFS) OpenDir(cipherPath string, context *fuse.Context) ([]fuse.
return entries, fuse.OK
}
+
+// StatFs - FUSE call
+func (rfs *reverseFS) StatFs(name string) *fuse.StatfsOut {
+ return rfs.loopbackfs.StatFs(name)
+}