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authorJakob Unterwurzacher2016-04-10 19:32:10 +0200
committerJakob Unterwurzacher2016-04-10 21:31:08 +0200
commitdb72fcea41f01f24ac3edb1cbf86d6b0be60f137 (patch)
treee65cc7c44b4c23bdee191015bfbbba1101370cd4 /internal/fusefrontend/fs_dir.go
parent63d3e517349a6c4774a3f75f2fa039c780eaf5f9 (diff)
longnames: fix fsstress failure, use dirfd
Using dirfd-relative operations allows safe lockless handling of the ".name" files.
Diffstat (limited to 'internal/fusefrontend/fs_dir.go')
-rw-r--r--internal/fusefrontend/fs_dir.go184
1 files changed, 111 insertions, 73 deletions
diff --git a/internal/fusefrontend/fs_dir.go b/internal/fusefrontend/fs_dir.go
index bcb93af..41e2101 100644
--- a/internal/fusefrontend/fs_dir.go
+++ b/internal/fusefrontend/fs_dir.go
@@ -16,50 +16,74 @@ import (
"github.com/rfjakob/gocryptfs/internal/toggledlog"
)
-func (fs *FS) Mkdir(relPath string, mode uint32, context *fuse.Context) (code fuse.Status) {
- if fs.isFiltered(relPath) {
+func (fs *FS) mkdirWithIv(cPath string, mode uint32) error {
+ // Between the creation of the directory and the creation of gocryptfs.diriv
+ // the directory is inconsistent. Take the lock to prevent other readers.
+ fs.dirIVLock.Lock()
+ // The new directory may take the place of an older one that is still in the cache
+ fs.nameTransform.DirIVCache.Clear()
+ defer fs.dirIVLock.Unlock()
+ err := os.Mkdir(cPath, os.FileMode(mode))
+ if err != nil {
+ return err
+ }
+ // Create gocryptfs.diriv
+ err = nametransform.WriteDirIV(cPath)
+ if err != nil {
+ err2 := syscall.Rmdir(cPath)
+ if err2 != nil {
+ toggledlog.Warn.Printf("mkdirWithIv: rollback failed: %v", err2)
+ }
+ }
+ return err
+}
+
+func (fs *FS) Mkdir(newPath string, mode uint32, context *fuse.Context) (code fuse.Status) {
+ if fs.isFiltered(newPath) {
return fuse.EPERM
}
- encPath, err := fs.getBackingPath(relPath)
+ cPath, err := fs.getBackingPath(newPath)
if err != nil {
return fuse.ToStatus(err)
}
if !fs.args.DirIV {
- return fuse.ToStatus(os.Mkdir(encPath, os.FileMode(mode)))
+ return fuse.ToStatus(os.Mkdir(cPath, os.FileMode(mode)))
}
-
// We need write and execute permissions to create gocryptfs.diriv
origMode := mode
mode = mode | 0300
- // Create .name file to store the long file name if needed
- err = fs.nameTransform.WriteLongName(encPath, relPath)
- if err != nil {
- return fuse.ToStatus(err)
- }
- // The new directory may take the place of an older one that is still in the cache
- fs.nameTransform.DirIVCache.Clear()
- // Create directory
- fs.dirIVLock.Lock()
- defer fs.dirIVLock.Unlock()
- err = os.Mkdir(encPath, os.FileMode(mode))
- if err != nil {
- return fuse.ToStatus(err)
- }
- // Create gocryptfs.diriv inside
- err = nametransform.WriteDirIV(encPath)
- if err != nil {
- // This should not happen
- toggledlog.Warn.Printf("Mkdir: WriteDirIV failed: %v", err)
- err2 := syscall.Rmdir(encPath)
- if err2 != nil {
- toggledlog.Warn.Printf("Mkdir: Rmdir rollback failed: %v", err2)
+
+ // Handle long file name
+ cName := filepath.Base(cPath)
+ if nametransform.IsLongContent(cName) {
+ dirfd, err := os.Open(filepath.Dir(cPath))
+ if err != nil {
+ return fuse.ToStatus(err)
+ }
+ defer dirfd.Close()
+
+ // Create ".name"
+ err = fs.nameTransform.WriteLongName(dirfd, cName, newPath)
+ if err != nil {
+ return fuse.ToStatus(err)
+ }
+
+ // Create directory
+ err = fs.mkdirWithIv(cPath, mode)
+ if err != nil {
+ nametransform.DeleteLongName(dirfd, cName)
+ return fuse.ToStatus(err)
+ }
+ } else {
+ err = fs.mkdirWithIv(cPath, mode)
+ if err != nil {
+ return fuse.ToStatus(err)
}
- return fuse.ToStatus(err)
}
// Set permissions back to what the user wanted
if origMode != mode {
- err = os.Chmod(encPath, os.FileMode(origMode))
+ err = os.Chmod(cPath, os.FileMode(origMode))
if err != nil {
toggledlog.Warn.Printf("Mkdir: Chmod failed: %v", err)
}
@@ -68,97 +92,111 @@ func (fs *FS) Mkdir(relPath string, mode uint32, context *fuse.Context) (code fu
return fuse.OK
}
-func (fs *FS) Rmdir(name string, context *fuse.Context) (code fuse.Status) {
- encPath, err := fs.getBackingPath(name)
+func (fs *FS) Rmdir(path string, context *fuse.Context) (code fuse.Status) {
+ cPath, err := fs.getBackingPath(path)
if err != nil {
return fuse.ToStatus(err)
}
if !fs.args.DirIV {
- return fuse.ToStatus(syscall.Rmdir(encPath))
+ return fuse.ToStatus(syscall.Rmdir(cPath))
}
- // If the directory is not empty besides gocryptfs.diriv, do not even
- // attempt the dance around gocryptfs.diriv.
- fd, err := os.Open(encPath)
- if perr, ok := err.(*os.PathError); ok && perr.Err == syscall.EACCES {
+ parentDir := filepath.Dir(cPath)
+ parentDirFd, err := os.Open(parentDir)
+ if err != nil {
+ return fuse.ToStatus(err)
+ }
+ defer parentDirFd.Close()
+
+ cName := filepath.Base(cPath)
+ dirfdRaw, err := syscall.Openat(int(parentDirFd.Fd()), cName,
+ syscall.O_RDONLY, 0)
+ if err == syscall.EACCES {
// We need permission to read and modify the directory
toggledlog.Debug.Printf("Rmdir: handling EACCESS")
- fi, err2 := os.Stat(encPath)
- if err2 != nil {
- toggledlog.Debug.Printf("Rmdir: Stat: %v", err2)
- return fuse.ToStatus(err2)
+ // TODO use syscall.Fstatat once it is available in Go
+ var fi os.FileInfo
+ fi, err = os.Lstat(cPath)
+ if err != nil {
+ toggledlog.Debug.Printf("Rmdir: Stat: %v", err)
+ return fuse.ToStatus(err)
}
origMode := fi.Mode()
- newMode := origMode | 0700
- err2 = os.Chmod(encPath, newMode)
- if err2 != nil {
- toggledlog.Debug.Printf("Rmdir: Chmod failed: %v", err2)
+ // TODO use syscall.Chmodat once it is available in Go
+ err = os.Chmod(cPath, origMode|0700)
+ if err != nil {
+ toggledlog.Debug.Printf("Rmdir: Chmod failed: %v", err)
return fuse.ToStatus(err)
}
+ // Retry open
+ var st syscall.Stat_t
+ syscall.Lstat(cPath, &st)
+ dirfdRaw, err = syscall.Openat(int(parentDirFd.Fd()), cName,
+ syscall.O_RDONLY, 0)
+ // Undo the chmod if removing the directory failed
defer func() {
if code != fuse.OK {
- // Undo the chmod if removing the directory failed
- err3 := os.Chmod(encPath, origMode)
- if err3 != nil {
- toggledlog.Warn.Printf("Rmdir: Chmod rollback failed: %v", err2)
+ err := os.Chmod(cPath, origMode)
+ if err != nil {
+ toggledlog.Warn.Printf("Rmdir: Chmod rollback failed: %v", err)
}
}
}()
- // Retry open
- fd, err = os.Open(encPath)
}
if err != nil {
toggledlog.Debug.Printf("Rmdir: Open: %v", err)
return fuse.ToStatus(err)
}
- list, err := fd.Readdirnames(10)
- fd.Close()
+ dirfd := os.NewFile(uintptr(dirfdRaw), cName)
+ defer dirfd.Close()
+
+ children, err := dirfd.Readdirnames(10)
if err != nil {
- toggledlog.Debug.Printf("Rmdir: Readdirnames: %v", err)
+ toggledlog.Warn.Printf("Rmdir: Readdirnames: %v", err)
return fuse.ToStatus(err)
}
- if len(list) > 1 {
+ // If the directory is not empty besides gocryptfs.diriv, do not even
+ // attempt the dance around gocryptfs.diriv.
+ if len(children) > 1 {
return fuse.ToStatus(syscall.ENOTEMPTY)
- } else if len(list) == 0 {
- toggledlog.Warn.Printf("Rmdir: gocryptfs.diriv missing, allowing deletion")
- return fuse.ToStatus(syscall.Rmdir(encPath))
}
// Move "gocryptfs.diriv" to the parent dir as "gocryptfs.diriv.rmdir.XYZ"
- dirivPath := filepath.Join(encPath, nametransform.DirIVFilename)
- parentDir := filepath.Dir(encPath)
tmpName := fmt.Sprintf("gocryptfs.diriv.rmdir.%d", cryptocore.RandUint64())
- tmpDirivPath := filepath.Join(parentDir, tmpName)
- toggledlog.Debug.Printf("Rmdir: Renaming %s to %s", nametransform.DirIVFilename, tmpDirivPath)
- // The directory is in an inconsistent state between rename and rmdir. Protect against
- // concurrent readers.
+ toggledlog.Debug.Printf("Rmdir: Renaming %s to %s", nametransform.DirIVFilename, tmpName)
+ // The directory is in an inconsistent state between rename and rmdir.
+ // Protect against concurrent readers.
fs.dirIVLock.Lock()
defer fs.dirIVLock.Unlock()
- err = os.Rename(dirivPath, tmpDirivPath)
+ err = syscall.Renameat(int(dirfd.Fd()), nametransform.DirIVFilename,
+ int(parentDirFd.Fd()), tmpName)
if err != nil {
toggledlog.Warn.Printf("Rmdir: Renaming %s to %s failed: %v",
- nametransform.DirIVFilename, tmpDirivPath, err)
+ nametransform.DirIVFilename, tmpName, err)
return fuse.ToStatus(err)
}
// Actual Rmdir
- err = syscall.Rmdir(encPath)
+ // TODO Use syscall.Unlinkat with the AT_REMOVEDIR flag once it is available
+ // in Go
+ err = syscall.Rmdir(cPath)
if err != nil {
// This can happen if another file in the directory was created in the
// meantime, undo the rename
- err2 := os.Rename(tmpDirivPath, dirivPath)
- if err2 != nil {
+ err2 := syscall.Renameat(int(parentDirFd.Fd()), tmpName,
+ int(dirfd.Fd()), nametransform.DirIVFilename)
+ if err != nil {
toggledlog.Warn.Printf("Rmdir: Rename rollback failed: %v", err2)
}
return fuse.ToStatus(err)
}
// Delete "gocryptfs.diriv.rmdir.INODENUMBER"
- err = syscall.Unlink(tmpDirivPath)
+ err = syscall.Unlinkat(int(parentDirFd.Fd()), tmpName)
if err != nil {
toggledlog.Warn.Printf("Rmdir: Could not clean up %s: %v", tmpName, err)
}
- err = nametransform.DeleteLongName(encPath)
- if err != nil {
- toggledlog.Warn.Printf("Rmdir: Could not delete long name file: %v", err)
+ // Delete .name file
+ if nametransform.IsLongContent(cName) {
+ nametransform.DeleteLongName(parentDirFd, cName)
}
// The now-deleted directory may have been in the DirIV cache. Clear it.
fs.nameTransform.DirIVCache.Clear()
@@ -206,7 +244,7 @@ func (fs *FS) OpenDir(dirName string, context *fuse.Context) ([]fuse.DirEntry, f
}
if fs.args.LongNames {
- isLong := nametransform.IsLongName(cName)
+ isLong := nametransform.NameType(cName)
if isLong == nametransform.LongNameContent {
cNameLong, err := nametransform.ReadLongName(filepath.Join(cDirAbsPath, cName))
if err != nil {