From c1c41d279a33afdeb930009bdd305c39a9920dcf Mon Sep 17 00:00:00 2001 From: Jakob Unterwurzacher Date: Mon, 5 Jun 2023 14:22:21 +0200 Subject: fusefrontend: sharedstorage: keep file header on truncate With -sharedstorage, we keep the on-disk file header. Other mounts may have the file ID cached so we cannot mess with it. This makes TestOpenTruncate pass. --- internal/fusefrontend/file_allocate_truncate.go | 49 +++++++++++++++++++++---- 1 file 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() -- cgit v1.2.3