Posix ACL Support

This change adds support for Posix ACLs by storing them as an xattr
which is common practice for many Linux file systems.  Since the
Posix ACL is stored as an xattr it will not overwrite any existing
ZFS/NFSv4 ACLs which may have been set.  The Posix ACL will also
be non-functional on other platforms although it may be visible
as an xattr if that platform understands SA based xattrs.

By default Posix ACLs are disabled but they may be enabled with
the new 'aclmode=noacl|posixacl' property.  Set the property to
'posixacl' to enable them.  If ZFS/NFSv4 ACL support is ever added
an appropriate acltype will be added.

This change passes the POSIX Test Suite cleanly with the exception
of xacl/00.t test 45 which is incorrect for Linux (Ext4 fails too).

  http://www.tuxera.com/community/posix-test-suite/

Signed-off-by: Massimo Maggi <[email protected]>
Signed-off-by: Richard Yao <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #170

1 files changed, 31 insertions, 11 deletions

diff --git a/module/zfs/zpl_super.c b/module/zfs/zpl_super.c
index eee4a50e0..72859ac5c 100644
--- a/module/zfs/zpl_super.c
+++ b/module/zfs/zpl_super.c
@@ -179,28 +179,48 @@ zpl_umount_begin(struct super_block *sb)
 }
 
 /*
- * The Linux VFS automatically handles the following flags:
- * MNT_NOSUID, MNT_NODEV, MNT_NOEXEC, MNT_NOATIME, MNT_READONLY
+ * ZFS specific features must be explicitly handled here, the VFS will
+ * automatically handled the following generic functionality.
+ *
+ *   MNT_NOSUID,
+ *   MNT_NODEV,
+ *   MNT_NOEXEC,
+ *   MNT_NOATIME,
+ *   MNT_NODIRATIME,
+ *   MNT_READONLY,
+ *   MNT_STRICTATIME,
+ *   MS_SYNCHRONOUS,
+ *   MS_DIRSYNC,
+ *   MS_MANDLOCK.
  */
-#ifdef HAVE_SHOW_OPTIONS_WITH_DENTRY
 static int
-zpl_show_options(struct seq_file *seq, struct dentry *root)
+__zpl_show_options(struct seq_file *seq, zfs_sb_t *zsb)
 {
-	zfs_sb_t *zsb = root->d_sb->s_fs_info;
-
 	seq_printf(seq, ",%s", zsb->z_flags & ZSB_XATTR ? "xattr" : "noxattr");
 
+	switch (zsb->z_acl_type) {
+	case ZFS_ACLTYPE_POSIXACL:
+		seq_puts(seq, ",posixacl");
+		break;
+	default:
+		seq_puts(seq, ",noacl");
+		break;
+	}
+
 	return (0);
 }
+
+#ifdef HAVE_SHOW_OPTIONS_WITH_DENTRY
+static int
+zpl_show_options(struct seq_file *seq, struct dentry *root)
+{
+	return __zpl_show_options(seq, root->d_sb->s_fs_info);
+}
 #else
 static int
 zpl_show_options(struct seq_file *seq, struct vfsmount *vfsp)
 {
-	zfs_sb_t *zsb = vfsp->mnt_sb->s_fs_info;
-
-	seq_printf(seq, ",%s", zsb->z_flags & ZSB_XATTR ? "xattr" : "noxattr");
-
-	return (0);
+	return __zpl_show_options(seq, vfsp->mnt_sb->s_fs_info);
 }
 #endif /* HAVE_SHOW_OPTIONS_WITH_DENTRY */