9ns: --name and /mnt/9p/<name> mounts, qid.path as inode number, interrupts as Tflush

- --name NAME (default derived from the transport: socket basename, tcp-IP-PORT,
  spawned command, fdN) mounts at /mnt/9p/<name>; --mount still overrides.
  ensureMountpoint walks down and creates missing components, shadowing the
  deepest unwritable ancestor. NINE_MOUNT is the only exported variable.
- The inode number reported to the kernel is the 9P qid.path for every node,
  root included; a server handing qid.path 1 to a file (Pardes /self) no
  longer collides with the root.
- FUSE_INTERRUPT for the request in flight becomes Tflush; a blocked read
  returns EINTR when the server answers the flush, chunked transfers return
  short counts, other requests arriving meanwhile are stashed and served
  next. Servers ignoring Tflush still block until they answer.
- 9ns-test now covers nine/bridge/fuse; new adv_bridge_interrupt suite (28);
  9ns-itest grows to 88 checks.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

1 files changed, 10 insertions, 1 deletions

diff --git a/9ns/test/adv_bridge_hostile.py b/9ns/test/adv_bridge_hostile.py
index d353541..f676d2f 100755
--- a/9ns/test/adv_bridge_hostile.py
+++ b/9ns/test/adv_bridge_hostile.py
@@ -62,7 +62,8 @@ name_huge       / has an entry with a 60000-byte name
 name_dots       / lists "." and ".." too
 rerror_big      Twalk to nope: Rerror with 65535 bytes of text
 extra_reply     Rread on /f: an unsolicited Rclunk (tag 9) precedes the real reply
-never           Tread on /f: never reply (hang)
+never           Tread on /f: never reply (hang); the server stops reading, so a Tflush is never seen
+never_flush     Tread on /f: never reply, but keep serving: log every Tflush and answer Rflush
 close_mid       Tread on /f: close the socket without replying
 renegotiate     Tread on /f: an unsolicited Rversion precedes the real reply
 length_max      Tstat on /f: length = 2**64-1
@@ -142,6 +143,9 @@ class Server:
         parent.children[name] = n
         return n
 
+    def log(self, text):
+        print(text, flush=True)
+
     # -- framing ---------------------------------------------------------
     def frame(self, typ, tag, body):
         return s32(7 + len(body)) + s8(typ) + s16(tag) + body
@@ -196,6 +200,8 @@ class Server:
             self.fids[fid] = [self.root, False]
             return self.frame(Rattach, tag, self.root.qid(self))
         if typ == Tflush:
+            oldtag = r.u16()
+            self.log('Tflush tag=%d oldtag=%d' % (tag, oldtag))
             return self.frame(Rflush, tag, b'')
         if typ == Twalk:
             fid, newfid, nw = r.u32(), r.u32(), r.u16()
@@ -292,6 +298,9 @@ class Server:
                 if m == 'never':
                     time.sleep(3600)
                     return None
+                if m == 'never_flush':
+                    self.log('Tread tag=%d fid=%d hang' % (tag, fid))
+                    return b''
                 if m == 'close_mid':
                     return None
                 if m == 'renegotiate':