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-rw-r--r--internal/fusefrontend/file_allocate_truncate.go49
1 files changed, 41 insertions, 8 deletions
diff --git a/internal/fusefrontend/file_allocate_truncate.go b/internal/fusefrontend/file_allocate_truncate.go
index cae796e..4a3deb1 100644
--- a/internal/fusefrontend/file_allocate_truncate.go
+++ b/internal/fusefrontend/file_allocate_truncate.go
@@ -9,6 +9,8 @@ import (
"sync"
"syscall"
+ "github.com/rfjakob/gocryptfs/v2/internal/contentenc"
+
"github.com/hanwen/go-fuse/v2/fs"
"github.com/rfjakob/gocryptfs/v2/internal/syscallcompat"
@@ -92,20 +94,51 @@ func (f *File) Allocate(ctx context.Context, off uint64, sz uint64, mode uint32)
return f.truncateGrowFile(oldPlainSz, newPlainSz)
}
-// truncate - called from Setattr.
+// truncate - called from node.Setattr and file.Setattr.
func (f *File) truncate(newSize uint64) (errno syscall.Errno) {
var err error
// Common case first: Truncate to zero
if newSize == 0 {
- err = syscall.Ftruncate(int(f.fd.Fd()), 0)
- if err != nil {
- tlog.Warn.Printf("ino%d fh%d: Ftruncate(fd, 0) returned error: %v", f.qIno.Ino, f.intFd(), err)
- return fs.ToErrno(err)
+ if !f.rootNode.args.SharedStorage {
+ err = syscall.Ftruncate(int(f.fd.Fd()), 0)
+ if err != nil {
+ tlog.Warn.Printf("ino%d fh%d: Ftruncate(fd, 0) returned error: %v", f.qIno.Ino, f.intFd(), err)
+ return fs.ToErrno(err)
+ }
+ // Truncate to zero kills the file header
+ f.fileTableEntry.ID = nil
+ return 0
+ } else {
+ // With -sharedstorage, we keep the on-disk file header.
+ // Other mounts may have the file ID cached so we cannot mess with it.
+
+ // The file must have a header if we have the file ID cached,
+ // so we can blindly truncate.
+ if f.fileTableEntry.ID != nil {
+ return fs.ToErrno(syscall.Ftruncate(int(f.fd.Fd()), contentenc.HeaderLen))
+ }
+ // We don't have the file ID cached, so the file may be empty on disk.
+ // We dont't want to grow it, as this will create an all-zero header.
+ fi, err := f.fd.Stat()
+ if err != nil {
+ return fs.ToErrno(err)
+ }
+ if fi.Size() == 0 {
+ // nothing to do
+ return 0
+ }
+ if fi.Size() == contentenc.HeaderLen {
+ // nothing to do
+ return 0
+ } else if fi.Size() > contentenc.HeaderLen {
+ return fs.ToErrno(syscall.Ftruncate(int(f.fd.Fd()), contentenc.HeaderLen))
+ } else {
+ tlog.Warn.Printf("truncate i%d: partial header, size=%d", f.qIno.Ino, fi.Size())
+ return syscall.EIO
+ }
}
- // Truncate to zero kills the file header
- f.fileTableEntry.ID = nil
- return 0
}
+
// We need the old file size to determine if we are growing or shrinking
// the file
oldSize, err := f.statPlainSize()