Ignore redirection for nested mount

Summary: Currently eden redirection list will list all redirections include its nested mounts and redirection in the nested mounts. It is better to ignore the nested mounts and redirection in the nested mounts if list redirection from its ancestor mount.

Reviewed By: chadaustin

Differential Revision: D34156017

fbshipit-source-id: ba3ed5e6b5c79b4a62034f5f8563705cf886a44d

eden/fs/cli/doctor/check_redirections.py

@@ -22,7 +22,7 @@ def check_redirections(
     checkout: EdenCheckout,
     mount_table: mtab.MountTable,
 ) -> None:
-    redirs = get_effective_redirections(checkout, mount_table)
+    redirs = get_effective_redirections(checkout, mount_table, instance)
 
     for redir in redirs.values():
         if redir.state == RedirectionState.MATCHES_CONFIGURATION:

eden/fs/cli/main.py

@@ -244,7 +244,7 @@ files outside the repo rather than to ignore and clean them up.\n""",
 
         for mount in mounts:
             instance, checkout, _rel_path = require_checkout(args, mount)
-            self.usage_for_redirections(checkout, all_redirections, clean)
+            self.usage_for_redirections(checkout, all_redirections, clean, instance)
 
         if not all_redirections:
             self.writeln_ui("No redirection")
@@ -461,9 +461,15 @@ space by running:
             )
 
     def usage_for_redirections(
-        self, checkout: EdenCheckout, redirection_repos: Set[str], clean: bool
+        self,
+        checkout: EdenCheckout,
+        redirection_repos: Set[str],
+        clean: bool,
+        instance: EdenInstance,
     ) -> None:
-        redirections = redirect_mod.get_effective_redirections(checkout, mtab.new())
+        redirections = redirect_mod.get_effective_redirections(
+            checkout, mtab.new(), instance
+        )
         seen_paths = set()
         if len(redirections) > 0:
             for redir in redirections.values():
@@ -1287,7 +1293,7 @@ class ChownCmd(Subcmd):
 
         if not args.skip_redirection:
             for redir in redirect_mod.get_effective_redirections(
-                checkout, mtab.new()
+                checkout, mtab.new(), instance
             ).values():
                 target = redir.expand_target_abspath(checkout)
                 print(f"Chowning redirection: {redir.repo_path}...", end="", flush=True)

eden/fs/cli/rage.py

@@ -335,7 +335,7 @@ def print_eden_redirections(instance: EdenInstance, out: IO[bytes]) -> None:
         checkouts = instance.get_checkouts()
         for checkout in checkouts:
             out.write(bytes(checkout.path) + b"\n")
-            output = redirect_mod.prepare_redirection_list(checkout)
+            output = redirect_mod.prepare_redirection_list(checkout, instance)
             # append a tab at the beginning of every new line to indent
             output = output.replace("\n", "\n\t")
             out.write(b"\t" + output.encode() + b"\n")

eden/fs/cli/redirect.py

@@ -16,7 +16,7 @@ import stat
 import subprocess
 import sys
 from pathlib import Path
-from typing import Dict, Iterable, Optional
+from typing import Set, Dict, Iterable, Optional
 
 from thrift.Thrift import TApplicationException
 
@@ -493,8 +493,34 @@ def get_configured_redirections(checkout: EdenCheckout) -> Dict[str, Redirection
     return redirs
 
 
+def is_strict_subdir(base: bytes, sub_dir: bytes) -> bool:
+    return base != sub_dir and sub_dir.startswith(base)
+
+
+def get_nested_mounts(instance: EdenInstance, checkout_path_bytes: bytes) -> Set[bytes]:
+    """
+    Find out nested EdenFS mounts in the checkout path
+    """
+    nested_mounts = set()
+
+    for eden_mount in instance.get_mount_paths():
+        eden_mount_path_byte = bytes(Path(eden_mount)) + b"/"
+        if is_strict_subdir(checkout_path_bytes, eden_mount_path_byte):
+            nested_mounts.add(eden_mount_path_byte)
+    return nested_mounts
+
+
+def in_nested_mount(nested_mounts: Set[bytes], mount_point: bytes) -> bool:
+    for nested_mount in nested_mounts:
+        if os.path.realpath(nested_mount) == os.path.realpath(
+            mount_point
+        ) or mount_point.startswith(nested_mount):
+            return True
+    return False
+
+
 def get_effective_redirections(
-    checkout: EdenCheckout, mount_table: mtab.MountTable
+    checkout: EdenCheckout, mount_table: mtab.MountTable, instance: EdenInstance
 ) -> Dict[str, Redirection]:
     """Computes the complete set of redirections that are currently in effect.
     This is based on the explicitly configured settings but also factors in
@@ -502,32 +528,40 @@ def get_effective_redirections(
     """
     redirs = {}
     checkout_path_bytes = bytes(checkout.path) + b"/"
+
+    nested_mounts = get_nested_mounts(instance, checkout_path_bytes)
+
     for mount_info in mount_table.read():
         mount_point = mount_info.mount_point
-        if mount_point.startswith(checkout_path_bytes):
-            rel_path = os.fsdecode(mount_point[len(checkout_path_bytes) :])
-            # The is_bind_mount test may appear to be redundant but it is
-            # possible for mounts to layer such that we have:
-            #
-            # /my/repo    <-- fuse at the top of the vfs
-            # /my/repo/buck-out
-            # /my/repo    <-- earlier generation fuse at bottom
-            #
-            # The buck-out bind mount in the middle is visible in the
-            # mount table but is not visible via the VFS because there
-            # is a different /my/repo mounted over the top.
-            #
-            # We test whether we can see a mount point at that location
-            # before recording it in the effective redirection list so
-            # that we don't falsely believe that the bind mount is up.
-            if rel_path and is_bind_mount(Path(os.fsdecode(mount_point))):
-                redirs[rel_path] = Redirection(
-                    repo_path=Path(rel_path),
-                    redir_type=RedirectionType.UNKNOWN,
-                    target=None,
-                    source="mount",
-                    state=RedirectionState.UNKNOWN_MOUNT,
-                )
+        if not mount_point.startswith(checkout_path_bytes) or in_nested_mount(
+            nested_mounts, mount_point
+        ):
+            continue
+
+        rel_path = os.fsdecode(mount_point[len(checkout_path_bytes) :])
+
+        # The is_bind_mount test may appear to be redundant but it is
+        # possible for mounts to layer such that we have:
+        #
+        # /my/repo    <-- fuse at the top of the vfs
+        # /my/repo/buck-out
+        # /my/repo    <-- earlier generation fuse at bottom
+        #
+        # The buck-out bind mount in the middle is visible in the
+        # mount table but is not visible via the VFS because there
+        # is a different /my/repo mounted over the top.
+        #
+        # We test whether we can see a mount point at that location
+        # before recording it in the effective redirection list so
+        # that we don't falsely believe that the bind mount is up.
+        if rel_path and is_bind_mount(Path(os.fsdecode(mount_point))):
+            redirs[rel_path] = Redirection(
+                repo_path=Path(rel_path),
+                redir_type=RedirectionType.UNKNOWN,
+                target=None,
+                source="mount",
+                state=RedirectionState.UNKNOWN_MOUNT,
+            )
 
     for rel_path, redir in get_configured_redirections(checkout).items():
         is_in_mount_table = rel_path in redirs
@@ -630,9 +664,9 @@ def is_empty_dir(path: Path) -> bool:
     return True
 
 
-def prepare_redirection_list(checkout: EdenCheckout) -> str:
+def prepare_redirection_list(checkout: EdenCheckout, instance: EdenInstance) -> str:
     mount_table = mtab.new()
-    redirs = get_effective_redirections(checkout, mount_table)
+    redirs = get_effective_redirections(checkout, mount_table, instance)
     return create_redirection_configs(checkout, redirs.values(), False)
 
 
@@ -671,7 +705,7 @@ class ListCmd(Subcmd):
         instance, checkout, _rel_path = cmd_util.require_checkout(args, args.mount)
 
         mount_table = mtab.new()
-        redirs = get_effective_redirections(checkout, mount_table)
+        redirs = get_effective_redirections(checkout, mount_table, instance)
         print_redirection_configs(checkout, redirs.values(), args.json)
         return 0
 
@@ -745,7 +779,7 @@ class UnmountCmd(Subcmd):
     def run(self, args: argparse.Namespace) -> int:
         instance, checkout, _rel_path = cmd_util.require_checkout(args, args.mount)
         mount_table = mtab.new()
-        redirs = get_effective_redirections(checkout, mount_table)
+        redirs = get_effective_redirections(checkout, mount_table, instance)
 
         for redir in redirs.values():
             redir.remove_existing(checkout)
@@ -753,7 +787,7 @@ class UnmountCmd(Subcmd):
                 continue
 
         # recompute and display the current state
-        redirs = get_effective_redirections(checkout, mount_table)
+        redirs = get_effective_redirections(checkout, mount_table, instance)
         ok = True
         for redir in redirs.values():
             if redir.state == RedirectionState.MATCHES_CONFIGURATION:
@@ -794,9 +828,9 @@ class FixupCmd(Subcmd):
         )
 
     def run(self, args: argparse.Namespace) -> int:
-        _instance, checkout, _rel_path = cmd_util.require_checkout(args, args.mount)
+        instance, checkout, _rel_path = cmd_util.require_checkout(args, args.mount)
         mount_table = mtab.new()
-        redirs = get_effective_redirections(checkout, mount_table)
+        redirs = get_effective_redirections(checkout, mount_table, instance)
         for redir in redirs.values():
             if redir.state == RedirectionState.MATCHES_CONFIGURATION and not (
                 args.force_remount_bind_mounts and redir.type == RedirectionType.BIND
@@ -813,7 +847,7 @@ class FixupCmd(Subcmd):
             redir.apply(checkout)
 
         # recompute and display the current state
-        redirs = get_effective_redirections(checkout, mount_table)
+        redirs = get_effective_redirections(checkout, mount_table, instance)
         ok = True
         for redir in redirs.values():
             if redir.state != RedirectionState.MATCHES_CONFIGURATION:
@@ -984,7 +1018,7 @@ class AddCmd(Subcmd):
         # bring the redirection back online.
         # However, we keep this separate from the `redirs` list below for
         # the reasons stated in the comment above.
-        effective_redirs = get_effective_redirections(checkout, mtab.new())
+        effective_redirs = get_effective_redirections(checkout, mtab.new(), instance)
 
         try:
             args.repo_path = str(
@@ -1078,7 +1112,7 @@ class DelCmd(Subcmd):
             checkout.save_config(config)
             return 0
 
-        redirs = get_effective_redirections(checkout, mtab.new())
+        redirs = get_effective_redirections(checkout, mtab.new(), instance)
         redir = redirs.get(args.repo_path)
         if redir:
             # This path isn't possible to trigger until we add profiles,