Expose API for modifying fuse_conn_info.max_read

src/_pyfuse3.py

@@ -9,6 +9,7 @@
 the terms of the GNU LGPL.
 '''
 
+from dataclasses import dataclass
 import errno
 import functools
 import logging
@@ -44,6 +45,15 @@ async def wrapper(*args, **kwargs):  # type: ignore
     return wrapper
 
 
+@dataclass
+class ConnInfo:
+    '''
+    Instances of this class store information about the fuse connection.
+    The attributes correspond to the elements of the ``fuse_conn_info`` struct.
+    '''
+    max_read: int
+
+
 class Operations:
     '''
     This class defines the request handler methods that an pyfuse3 file system
@@ -65,12 +75,17 @@ class Operations:
     enable_writeback_cache: bool = False
     enable_acl: bool = False
 
-    def init(self) -> None:
+    def init(self, conn_info: ConnInfo) -> None:
         '''Initialize operations.
 
         This method will be called just before the file system starts handling
         requests. It must not raise any exceptions (not even `FUSEError`), since
         it is not handling a particular client request.
+
+        *conn_info* will be an instance of `ConnInfo`, containing fuse connection information.
+        Handler may modify some of its members in place. After the handler finishes
+        values stored will be read by libfuse. See `fuse_conn_info` struct reference.
+        Currently only `max_read` is supported.
         '''
 
         pass

src/handlers.pxi

@@ -45,9 +45,11 @@ cdef void fuse_init (void *userdata, fuse_conn_info *conn):
         conn.capable & FUSE_CAP_POSIX_ACL):
         conn.want |= FUSE_CAP_POSIX_ACL
 
-    # Blocking rather than async, in case we decide to let the
-    # init hander modify `conn` in the future.
-    operations.init()
+    cdef object conn_obj = ConnInfo(max_read=conn.max_read)
+    # Blocking rather than async, to let the init hander modify `conn_obj`.
+    operations.init(conn_obj)
+    conn.max_read = conn_obj.max_read
+
 
 cdef void fuse_lookup (fuse_req_t req, fuse_ino_t parent,
                        const_char *name):

src/pyfuse3.pyx

@@ -72,7 +72,7 @@ import typing
 import _pyfuse3
 _pyfuse3.FUSEError = FUSEError
 
-from _pyfuse3 import Operations, async_wrapper
+from _pyfuse3 import Operations, async_wrapper, ConnInfo
 
 if typing.TYPE_CHECKING:
     from _pyfuse3 import FileHandleT, FileNameT, FlagT, InodeT, ModeT

test/test_fs.py

@@ -166,6 +166,9 @@ def __init__(self, cross_process):
         self.status.entry_timeout = 99999
         self.status.attr_timeout = 99999
 
+    def init(self, conn_info):
+        conn_info.max_read = 4096
+
     async def getattr(self, inode, ctx=None):
         entry = pyfuse3.EntryAttributes()
         if inode == pyfuse3.ROOT_INODE:
@@ -268,6 +271,7 @@ def run_fs(mountpoint, cross_process):
     testfs = Fs(cross_process)
     fuse_options = set(pyfuse3.default_options)
     fuse_options.add('fsname=pyfuse3_testfs')
+    fuse_options.add('max_read=4096')
     pyfuse3.init(testfs, mountpoint, fuse_options)
     try:
         trio.run(pyfuse3.main)