Now I start the server with -D flag and try ''echo hello >>foo" on Linux. The server side on Plan 9 say:
<-5- Twalk tag 1 fid 408 newfid 437 nwname 1 0:foo -5-> Rwalk tag 1 nwqid 1 0:(0000000000000000 0 ) <-5- Tstat tag 1 fid 437 -5-> Rstat tag 1 stat 'foo' 'bootes' 'bootes' 'unknown' q (0000000000000000 0 ) m 0666 at 1325748319 mt 1325748319 l 0 t 0 d 0 <-5- Tclunk tag 1 fid 437 -5-> Rclunk tag 1 <-5- Twalk tag 2 fid 408 newfid 437 nwname 1 0:foo -5-> Rwalk tag 2 nwqid 1 0:(0000000000000000 0 ) <-5- Tstat tag 2 fid 437 -5-> Rstat tag 2 stat 'foo' 'bootes' 'bootes' 'unknown' q (0000000000000000 0 ) m 0666 at 1325748319 mt 1325748319 l 0 t 0 d 0 <-5- Tclunk tag 2 fid 437 -5-> Rclunk tag 2 <-5- Twalk tag 2 fid 408 newfid 438 nwname 1 0:foo -5-> Rwalk tag 2 nwqid 1 0:(0000000000000000 0 ) <-5- Topen tag 2 fid 438 mode 1 fid mode is 0x1 -5-> Ropen tag 2 qid (0000000000000000 0 ) iounit 0 <-5- Tstat tag 2 fid 438 -5-> Rstat tag 2 stat 'foo' 'bootes' 'bootes' 'unknown' q (0000000000000000 0 ) m 0666 at 1325748319 mt 1325748319 l 0 t 0 d 0 <-5- Twrite tag 6 fid 438 offset 0 count 6 'hello' -5-> Rwrite tag 6 count 6 <-5- Tclunk tag 6 fid 438 -5-> Rclunk tag 6 I will read more 9P examples in order to implement a wstat. Thank you Yaroslav and Andrey, it is worth to learn from you.