NAS-131762 / 25.04 / Add private NFS method to clear rmtab or selecte…

…d entries. (#15276)


Make call to clear rmtab from nfs.setup_directories.
Cannot use middleware setup hook because /var/db/system/nfs is not yet available at that point.

src/middlewared/middlewared/plugins/nfs.py

@@ -188,6 +188,12 @@ def setup_directories(self):
             except Exception:
                 self.logger.error('Unexpected failure initializing %r', path, exc_info=True)
 
+        # Clear rmtab on boot.
+        # We call this here because /var/db/system/nfs is not yet available
+        # in a middleware 'setup' hook.  See NAS-131762
+        if not self.middleware.call_sync('system.ready'):
+            self.middleware.call_sync('nfs.clear_nfs3_rmtab')
+
     @private
     async def nfs_extend(self, nfs):
         keytab_has_nfs = await self.middleware.call("kerberos.keytab.has_nfs_principal")

src/middlewared/middlewared/plugins/nfs_/status.py

@@ -1,12 +1,13 @@
+import os
+import tempfile
+import yaml
+
+from contextlib import suppress
 from middlewared.plugins.nfs import NFSServicePathInfo
 from middlewared.schema import accepts, Int, returns, Str, Dict
 from middlewared.service import Service, private, filterable, filterable_returns
-from middlewared.utils import filter_list
 from middlewared.service_exception import CallError
-from contextlib import suppress
-
-import yaml
-import os
+from middlewared.utils import filter_list
 
 
 class NFSService(Service):
@@ -31,6 +32,39 @@ def get_rmtab(self):
 
         return entries
 
+    @private
+    def clear_nfs3_rmtab(self, ip_to_clear=["all"]):
+        """
+        Clear some or all NFSv3 client entries in rmtab.
+        rmtab can become clogged with stale entries, this provides a
+        method to clear all or selected entries.
+        Optional input: list of ip to remove, e.g. ip_to_clear=["a.b.c.d"]
+        DEFAULT: Clear all entries
+        """
+        rmtab = os.path.join(NFSServicePathInfo.STATEDIR.path(), "rmtab")
+        with suppress(FileNotFoundError):
+            # Handle default:  clear all
+            if "all" in ip_to_clear:
+                with open(rmtab, "w"):
+                    # Use 'w' open to truncate
+                    pass
+            else:
+                # Replace rmtab excluding ip_to_clear
+                with tempfile.NamedTemporaryFile(
+                    mode='wt',
+                    dir=NFSServicePathInfo.STATEDIR.path(),
+                    delete=False
+                ) as outf:
+                    with open(rmtab, "r") as inf:
+                        for entry in inf:
+                            if entry.split(':')[0] in ip_to_clear:
+                                continue
+                            else:
+                                outf.write(entry)
+                    outf.flush()
+                    os.fsync(outf.fileno())
+                    os.rename(outf.name, rmtab)
+
     # NFS_WRITE because this exposes hostnames and IP addresses
     # READONLY is considered administrative-level permission
     @filterable(roles=['READONLY_ADMIN', 'SHARING_NFS_WRITE'])