Accessing ZFS snapshots over SMB

[Ralph Böhme]

Hi!

https://bugzilla.samba.org/show_bug.cgi?id=13175

Currently trying to access ZFS snapshot directories over SMB fails:

$ bin/smbclient -U slow%x //localhost/test
Try "help" to get a list of possible commands.
smb: \> ls
  .                                   D        0  Tue Dec  5 09:05:27 2017
  ..                                  D        0  Tue Dec  5 08:49:27 2017
  .zfs                               DH        0  Tue Dec  5 08:49:27 2017
  test                                D        0  Tue Dec  5 09:06:06 2017

                1949611 blocks of size 1024. 1949578 blocks available
smb: \> ls .zfs/*
NT_STATUS_NOT_SUPPORTED listing \.zfs\*

This happens because the acl() library call fails with ENOTSUP on the snapshot
directories. This could be easily fixed by synthesizing an ACL based on the
POSIX mode, much like the getfacl() command on FreeBSD does. The attached WIP
patch implements this.

Question: do we want this?

-slow

-- 
Ralph Boehme, Samba Team       https://samba.org/
Samba Developer, SerNet GmbH   https://sernet.de/en/samba/
-------------- next part --------------
From 7d72b5dcf2634f355213eb17003de0777479c0a3 Mon Sep 17 00:00:00 2001
From: Ralph Boehme <slow at samba.org>
Date: Tue, 5 Dec 2017 08:28:28 +0100
Subject: [PATCH] vfs_zfsacl: return synthesized ACL when ZFS return ENOTSUP

This allows accessing the ZFS .snapshots directory where ZFS returns
ENOTSUP when calling acl(".snapshots").
---
 source3/modules/vfs_zfsacl.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/source3/modules/vfs_zfsacl.c b/source3/modules/vfs_zfsacl.c
index 2e277c67a24..6ca638eee6f 100644
--- a/source3/modules/vfs_zfsacl.c
+++ b/source3/modules/vfs_zfsacl.c
@@ -238,6 +238,14 @@ static NTSTATUS zfsacl_fget_nt_acl(struct vfs_handle_struct *handle,
 				       fsp->fsp_name, &pacl);
 	if (!NT_STATUS_IS_OK(status)) {
 		TALLOC_FREE(frame);
+		if (!NT_STATUS_EQUAL(status, NT_STATUS_NOT_SUPPORTED)) {
+			return status;
+		}
+		status = make_default_filesystem_acl(mem_ctx,
+						     DEFAULT_ACL_POSIX,
+						     fsp->fsp_name->base_name,
+						     &fsp->fsp_name->st,
+						     ppdesc);
 		return status;
 	}
 
@@ -259,7 +267,25 @@ static NTSTATUS zfsacl_get_nt_acl(struct vfs_handle_struct *handle,
 
 	status = zfs_get_nt_acl_common(handle->conn, frame, smb_fname, &pacl);
 	if (!NT_STATUS_IS_OK(status)) {
+		SMB_STRUCT_STAT st;
+
 		TALLOC_FREE(frame);
+		if (!NT_STATUS_EQUAL(status, NT_STATUS_NOT_SUPPORTED)) {
+			return status;
+		}
+
+		if (!VALID_STAT(smb_fname->st)) {
+			DBG_ERR("No stat info for [%s]\n",
+				smb_fname_str_dbg(smb_fname));
+			return NT_STATUS_INTERNAL_ERROR;
+		}
+		st = smb_fname->st;
+
+		status = make_default_filesystem_acl(mem_ctx,
+						     DEFAULT_ACL_POSIX,
+						     smb_fname->base_name,
+						     &st,
+						     ppdesc);
 		return status;
 	}
 
-- 
2.14.1