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Diffstat (limited to 'runsc/fsgofer/fsgofer.go')
-rw-r--r--runsc/fsgofer/fsgofer.go128
1 files changed, 88 insertions, 40 deletions
diff --git a/runsc/fsgofer/fsgofer.go b/runsc/fsgofer/fsgofer.go
index 1316dc618..b325afa63 100644
--- a/runsc/fsgofer/fsgofer.go
+++ b/runsc/fsgofer/fsgofer.go
@@ -91,14 +91,29 @@ type attachPoint struct {
prefix string
conf Config
- mu sync.Mutex
- attached bool
+ // attachedMu protects attached.
+ attachedMu sync.Mutex
+ attached bool
+
+ // deviceMu protects devices and nextDevice.
+ deviceMu sync.Mutex
+
+ // nextDevice is the next device id that will be allocated.
+ nextDevice uint8
+
+ // devices is a map from actual host devices to "small" integers that
+ // can be combined with host inode to form a unique virtual inode id.
+ devices map[uint64]uint8
}
// NewAttachPoint creates a new attacher that gives local file
// access to all files under 'prefix'.
func NewAttachPoint(prefix string, c Config) p9.Attacher {
- return &attachPoint{prefix: prefix, conf: c}
+ return &attachPoint{
+ prefix: prefix,
+ conf: c,
+ devices: make(map[uint64]uint8),
+ }
}
// Attach implements p9.Attacher.
@@ -131,21 +146,45 @@ func (a *attachPoint) Attach(appPath string) (p9.File, error) {
return nil, fmt.Errorf("failed to stat file %q, err: %v", root, err)
}
- a.mu.Lock()
- defer a.mu.Unlock()
+ a.attachedMu.Lock()
+ defer a.attachedMu.Unlock()
if a.attached {
f.Close()
return nil, fmt.Errorf("attach point already attached, prefix: %s", a.prefix)
}
a.attached = true
- return newLocalFile(a.conf, f, root, stat)
+ return newLocalFile(a, f, root, stat)
}
-func makeQID(stat syscall.Stat_t) p9.QID {
+// makeQID returns a unique QID for the given stat buffer.
+func (a *attachPoint) makeQID(stat syscall.Stat_t) p9.QID {
+ a.deviceMu.Lock()
+ defer a.deviceMu.Unlock()
+
+ // First map the host device id to a unique 8-bit integer.
+ dev, ok := a.devices[stat.Dev]
+ if !ok {
+ a.devices[stat.Dev] = a.nextDevice
+ dev = a.nextDevice
+ a.nextDevice++
+ if a.nextDevice < dev {
+ panic(fmt.Sprintf("device id overflow! map: %+v", a.devices))
+ }
+ }
+
+ // Construct a "virtual" inode id with the uint8 device number in the
+ // first 8 bits, and the rest of the bits from the host inode id.
+ maskedIno := stat.Ino & 0x00ffffffffffffff
+ if maskedIno != stat.Ino {
+ log.Warningf("first 8 bytes of host inode id %x will be truncated to construct virtual inode id", stat.Ino)
+ }
+ ino := uint64(dev)<<56 | maskedIno
+ log.Debugf("host inode %x on device %x mapped to virtual inode %x", stat.Ino, stat.Dev, ino)
+
return p9.QID{
Type: p9.FileMode(stat.Mode).QIDType(),
- Path: stat.Ino,
+ Path: ino,
}
}
@@ -193,6 +232,9 @@ func isNameValid(name string) bool {
type localFile struct {
p9.DefaultWalkGetAttr
+ // attachPoint is the attachPoint that serves this localFile.
+ attachPoint *attachPoint
+
// mu protects 'hostPath' when file is renamed.
mu sync.Mutex
@@ -213,8 +255,6 @@ type localFile struct {
ft fileType
- conf Config
-
// readDirMu protects against concurrent Readdir calls.
readDirMu sync.Mutex
}
@@ -228,7 +268,8 @@ func openAnyFile(parent *localFile, name string) (*os.File, string, error) {
symlinkIdx := len(modes) - 1
startIdx := 0
- if parent.conf.ROMount || parent.conf.LazyOpenForWrite {
+ conf := parent.attachPoint.conf
+ if conf.ROMount || conf.LazyOpenForWrite {
// Skip attempt to open in RDWR based on configuration.
startIdx = 1
}
@@ -269,7 +310,7 @@ func openAnyFile(parent *localFile, name string) (*os.File, string, error) {
return os.NewFile(uintptr(fd), newPath), newPath, nil
}
-func newLocalFile(conf Config, file *os.File, path string, stat syscall.Stat_t) (*localFile, error) {
+func newLocalFile(a *attachPoint, file *os.File, path string, stat syscall.Stat_t) (*localFile, error) {
var ft fileType
switch stat.Mode & syscall.S_IFMT {
case syscall.S_IFREG:
@@ -282,9 +323,9 @@ func newLocalFile(conf Config, file *os.File, path string, stat syscall.Stat_t)
return nil, syscall.EINVAL
}
return &localFile{
+ attachPoint: a,
hostPath: path,
controlFile: file,
- conf: conf,
mode: invalidMode,
ft: ft,
}, nil
@@ -338,7 +379,7 @@ func (l *localFile) Open(mode p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) {
// Check if control file can be used or if a new open must be created.
var newFile *os.File
- if mode == p9.ReadOnly || !l.conf.LazyOpenForWrite {
+ if mode == p9.ReadOnly || !l.attachPoint.conf.LazyOpenForWrite {
log.Debugf("Open reusing control file, mode: %v, %q", mode, l.controlFile.Name())
newFile = l.controlFile
} else {
@@ -372,13 +413,14 @@ func (l *localFile) Open(mode p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) {
// Set fields on success
l.openedFile = newFile
l.mode = mode
- return fd, makeQID(stat), 0, nil
+ return fd, l.attachPoint.makeQID(stat), 0, nil
}
// Create implements p9.File.
func (l *localFile) Create(name string, mode p9.OpenFlags, perm p9.FileMode, uid p9.UID, gid p9.GID) (*fd.FD, p9.File, p9.QID, uint32, error) {
- if l.conf.ROMount {
- if l.conf.PanicOnWrite {
+ conf := l.attachPoint.conf
+ if conf.ROMount {
+ if conf.PanicOnWrite {
panic("attempt to write to RO mount")
}
return nil, nil, p9.QID{}, 0, syscall.EBADF
@@ -423,19 +465,20 @@ func (l *localFile) Create(name string, mode p9.OpenFlags, perm p9.FileMode, uid
cPath := path.Join(l.hostPath, name)
f := os.NewFile(uintptr(fd), cPath)
c := &localFile{
+ attachPoint: l.attachPoint,
hostPath: cPath,
controlFile: f,
openedFile: f,
mode: mode,
- conf: l.conf,
}
- return newFDMaybe(c.openedFile), c, makeQID(stat), 0, nil
+ return newFDMaybe(c.openedFile), c, l.attachPoint.makeQID(stat), 0, nil
}
// Mkdir implements p9.File.
func (l *localFile) Mkdir(name string, perm p9.FileMode, uid p9.UID, gid p9.GID) (p9.QID, error) {
- if l.conf.ROMount {
- if l.conf.PanicOnWrite {
+ conf := l.attachPoint.conf
+ if conf.ROMount {
+ if conf.PanicOnWrite {
panic("attempt to write to RO mount")
}
return p9.QID{}, syscall.EBADF
@@ -464,7 +507,7 @@ func (l *localFile) Mkdir(name string, perm p9.FileMode, uid p9.UID, gid p9.GID)
if err != nil {
return p9.QID{}, extractErrno(err)
}
- return makeQID(stat), nil
+ return l.attachPoint.makeQID(stat), nil
}
// Walk implements p9.File.
@@ -485,12 +528,12 @@ func (l *localFile) Walk(names []string) ([]p9.QID, p9.File, error) {
defer l.mu.Unlock()
c := &localFile{
+ attachPoint: l.attachPoint,
hostPath: l.hostPath,
controlFile: os.NewFile(uintptr(newFd), l.hostPath),
mode: invalidMode,
- conf: l.conf,
}
- return []p9.QID{makeQID(stat)}, c, nil
+ return []p9.QID{l.attachPoint.makeQID(stat)}, c, nil
}
var qids []p9.QID
@@ -508,12 +551,12 @@ func (l *localFile) Walk(names []string) ([]p9.QID, p9.File, error) {
if err != nil {
return nil, nil, extractErrno(err)
}
- c, err := newLocalFile(last.conf, f, path, stat)
+ c, err := newLocalFile(last.attachPoint, f, path, stat)
if err != nil {
return nil, nil, extractErrno(err)
}
- qids = append(qids, makeQID(stat))
+ qids = append(qids, l.attachPoint.makeQID(stat))
last = c
}
return qids, last, nil
@@ -586,15 +629,16 @@ func (l *localFile) GetAttr(_ p9.AttrMask) (p9.QID, p9.AttrMask, p9.Attr, error)
CTime: true,
}
- return makeQID(stat), valid, attr, nil
+ return l.attachPoint.makeQID(stat), valid, attr, nil
}
// SetAttr implements p9.File. Due to mismatch in file API, options
// cannot be changed atomicaly and user may see partial changes when
// an error happens.
func (l *localFile) SetAttr(valid p9.SetAttrMask, attr p9.SetAttr) error {
- if l.conf.ROMount {
- if l.conf.PanicOnWrite {
+ conf := l.attachPoint.conf
+ if conf.ROMount {
+ if conf.PanicOnWrite {
panic("attempt to write to RO mount")
}
return syscall.EBADF
@@ -624,7 +668,7 @@ func (l *localFile) SetAttr(valid p9.SetAttrMask, attr p9.SetAttr) error {
}
fd := l.controlFD()
- if l.conf.LazyOpenForWrite && l.ft == regular {
+ if conf.LazyOpenForWrite && l.ft == regular {
// Regular files are opened in RO mode when lazy open is set.
// Thus it needs to be reopened here for write.
f, err := os.OpenFile(l.hostPath, openFlags|os.O_WRONLY, 0)
@@ -733,8 +777,9 @@ func (*localFile) Remove() error {
// Rename implements p9.File.
func (l *localFile) Rename(directory p9.File, name string) error {
- if l.conf.ROMount {
- if l.conf.PanicOnWrite {
+ conf := l.attachPoint.conf
+ if conf.ROMount {
+ if conf.PanicOnWrite {
panic("attempt to write to RO mount")
}
return syscall.EBADF
@@ -803,8 +848,9 @@ func (l *localFile) WriteAt(p []byte, offset uint64) (int, error) {
// Symlink implements p9.File.
func (l *localFile) Symlink(target, newName string, uid p9.UID, gid p9.GID) (p9.QID, error) {
- if l.conf.ROMount {
- if l.conf.PanicOnWrite {
+ conf := l.attachPoint.conf
+ if conf.ROMount {
+ if conf.PanicOnWrite {
panic("attempt to write to RO mount")
}
return p9.QID{}, syscall.EBADF
@@ -831,13 +877,14 @@ func (l *localFile) Symlink(target, newName string, uid p9.UID, gid p9.GID) (p9.
if err != nil {
return p9.QID{}, extractErrno(err)
}
- return makeQID(stat), nil
+ return l.attachPoint.makeQID(stat), nil
}
// Link implements p9.File.
func (l *localFile) Link(target p9.File, newName string) error {
- if l.conf.ROMount {
- if l.conf.PanicOnWrite {
+ conf := l.attachPoint.conf
+ if conf.ROMount {
+ if conf.PanicOnWrite {
panic("attempt to write to RO mount")
}
return syscall.EBADF
@@ -862,8 +909,9 @@ func (*localFile) Mknod(_ string, _ p9.FileMode, _ uint32, _ uint32, _ p9.UID, _
// UnlinkAt implements p9.File.
func (l *localFile) UnlinkAt(name string, flags uint32) error {
- if l.conf.ROMount {
- if l.conf.PanicOnWrite {
+ conf := l.attachPoint.conf
+ if conf.ROMount {
+ if conf.PanicOnWrite {
panic("attempt to write to RO mount")
}
return syscall.EBADF
@@ -906,7 +954,7 @@ func (l *localFile) Readdir(offset uint64, count uint32) ([]p9.Dirent, error) {
if err != nil {
continue
}
- qid := makeQID(stat)
+ qid := l.attachPoint.makeQID(stat)
dirents = append(dirents, p9.Dirent{
QID: qid,
Type: qid.Type,
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-02 18:16:01 +0000