add open release, refactor

weed/mount/weedfs_file_sync.go

@@ -0,0 +1,70 @@
+package mount
+
+import (
+	"github.com/hanwen/go-fuse/v2/fuse"
+)
+
+/**
+ * Flush method
+ *
+ * This is called on each close() of the opened file.
+ *
+ * Since file descriptors can be duplicated (dup, dup2, fork), for
+ * one open call there may be many flush calls.
+ *
+ * Filesystems shouldn't assume that flush will always be called
+ * after some writes, or that if will be called at all.
+ *
+ * fi->fh will contain the value set by the open method, or will
+ * be undefined if the open method didn't set any value.
+ *
+ * NOTE: the name of the method is misleading, since (unlike
+ * fsync) the filesystem is not forced to flush pending writes.
+ * One reason to flush data is if the filesystem wants to return
+ * write errors during close.  However, such use is non-portable
+ * because POSIX does not require [close] to wait for delayed I/O to
+ * complete.
+ *
+ * If the filesystem supports file locking operations (setlk,
+ * getlk) it should remove all locks belonging to 'fi->owner'.
+ *
+ * If this request is answered with an error code of ENOSYS,
+ * this is treated as success and future calls to flush() will
+ * succeed automatically without being send to the filesystem
+ * process.
+ *
+ * Valid replies:
+ *   fuse_reply_err
+ *
+ * @param req request handle
+ * @param ino the inode number
+ * @param fi file information
+ *
+ * [close]: http://pubs.opengroup.org/onlinepubs/9699919799/functions/close.html
+ */
+func (wfs *WFS) Flush(cancel <-chan struct{}, in *fuse.FlushIn) fuse.Status {
+	return fuse.ENOSYS
+}
+
+/**
+ * Synchronize file contents
+ *
+ * If the datasync parameter is non-zero, then only the user data
+ * should be flushed, not the meta data.
+ *
+ * If this request is answered with an error code of ENOSYS,
+ * this is treated as success and future calls to fsync() will
+ * succeed automatically without being send to the filesystem
+ * process.
+ *
+ * Valid replies:
+ *   fuse_reply_err
+ *
+ * @param req request handle
+ * @param ino the inode number
+ * @param datasync flag indicating if only data should be flushed
+ * @param fi file information
+ */
+func (wfs *WFS) Fsync(cancel <-chan struct{}, in *fuse.FsyncIn) (code fuse.Status) {
+	return fuse.ENOSYS
+}