support write once read many

fix https://github.com/seaweedfs/seaweedfs/issues/5954

weed/command/mount.go

@@ -33,6 +33,7 @@ type MountOptions struct {
 	localSocket        *string
 	disableXAttr       *bool
 	extraOptions       []string
+	writeOnceReadMany  *bool
 }
 
 var (
@@ -70,6 +71,7 @@ func init() {
 	mountOptions.debugPort = cmdMount.Flag.Int("debug.port", 6061, "http port for debugging")
 	mountOptions.localSocket = cmdMount.Flag.String("localSocket", "", "default to /tmp/seaweedfs-mount-<mount_dir_hash>.sock")
 	mountOptions.disableXAttr = cmdMount.Flag.Bool("disableXAttr", false, "disable xattr")
+	mountOptions.writeOnceReadMany = cmdMount.Flag.Bool("writeOnceReadMany", false, "write once, read many times")
 
 	mountCpuProfile = cmdMount.Flag.String("cpuprofile", "", "cpu profile output file")
 	mountMemProfile = cmdMount.Flag.String("memprofile", "", "memory profile output file")

weed/command/mount_std.go

@@ -247,6 +247,7 @@ func RunMount(option *MountOptions, umask os.FileMode) bool {
 		Cipher:             cipher,
 		UidGidMapper:       uidGidMapper,
 		DisableXAttr:       *option.disableXAttr,
+		WriteOnceReadMany:  *option.writeOnceReadMany,
 	})
 
 	// create mount root

weed/mount/weedfs.go

@@ -46,6 +46,8 @@ type Option struct {
 	Quota              int64
 	DisableXAttr       bool
 
+	WriteOnceReadMany bool
+
 	MountUid         uint32
 	MountGid         uint32
 	MountMode        os.FileMode

weed/mount/weedfs_file_io.go

@@ -62,7 +62,7 @@ import (
 */
 func (wfs *WFS) Open(cancel <-chan struct{}, in *fuse.OpenIn, out *fuse.OpenOut) (status fuse.Status) {
 	var fileHandle *FileHandle
-	fileHandle, status = wfs.AcquireHandle(in.NodeId, in.Uid, in.Gid)
+	fileHandle, status = wfs.AcquireHandle(in.NodeId, in.Flags, in.Uid, in.Gid)
 	if status == fuse.OK {
 		out.Fh = uint64(fileHandle.fh)
 		// TODO https://github.com/libfuse/libfuse/blob/master/include/fuse_common.h#L64

weed/mount/weedfs_filehandle.go

@@ -3,12 +3,20 @@ package mount
 import (
 	"github.com/hanwen/go-fuse/v2/fuse"
 	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
+	"time"
 )
 
-func (wfs *WFS) AcquireHandle(inode uint64, uid, gid uint32) (fileHandle *FileHandle, status fuse.Status) {
+func (wfs *WFS) AcquireHandle(inode uint64, flags, uid, gid uint32) (fileHandle *FileHandle, status fuse.Status) {
 	var entry *filer_pb.Entry
 	_, _, entry, status = wfs.maybeReadEntry(inode)
 	if status == fuse.OK {
+		if entry != nil && wfs.option.WriteOnceReadMany {
+			if entry.Attributes.Mtime+10 < time.Now().Unix() {
+				if flags&fuse.O_ANYWRITE != 0 {
+					return nil, fuse.EPERM
+				}
+			}
+		}
 		// need to AcquireFileHandle again to ensure correct handle counter
 		fileHandle = wfs.fhmap.AcquireFileHandle(wfs, inode, entry)
 	}