Add support for FreeBSD's Solaris style extended attribute interface

include/os/freebsd/spl/sys/vnode_impl.h

@@ -227,6 +227,7 @@ struct taskq;
 #define	LOOKUP_XATTR		0x02	/* lookup up extended attr dir */
 #define	CREATE_XATTR_DIR	0x04	/* Create extended attr dir */
 #define	LOOKUP_HAVE_SYSATTR_DIR	0x08	/* Already created virtual GFS dir */
+#define	LOOKUP_NAMED_ATTR	0x10	/* Lookup a named attribute */
 
 /*
  * Public vnode manipulation functions.

include/sys/xvattr.h

@@ -311,6 +311,7 @@ xva_getxoptattr(xvattr_t *xvap)
  */
 #define	V_ACE_MASK	0x1	/* mask represents  NFSv4 ACE permissions */
 #define	V_APPEND	0x2	/* want to do append only check */
+#define	V_NAMEDATTR	0x4	/* is a named attribute check */
 
 /*
  * Structure used on VOP_GETSECATTR and VOP_SETSECATTR operations

module/os/freebsd/zfs/zfs_acl.c

@@ -2357,10 +2357,42 @@ zfs_zaccess(znode_t *zp, int mode, int flags, boolean_t skipaclchk, cred_t *cr,
 	 * In FreeBSD, we don't care about permissions of individual ADS.
 	 * Note that not checking them is not just an optimization - without
 	 * this shortcut, EA operations may bogusly fail with EACCES.
+	 *
+	 * If this is a named attribute lookup, do the checks.
 	 */
+#if __FreeBSD_version >= 1500040
+	if ((zp->z_pflags & ZFS_XATTR) && (flags & V_NAMEDATTR) == 0)
+#else
 	if (zp->z_pflags & ZFS_XATTR)
+#endif
 		return (0);
 
+	/*
+	 * If a named attribute directory then validate against base file
+	 */
+	if (is_attr) {
+		if ((error = zfs_zget(ZTOZSB(zp),
+		    zp->z_xattr_parent, &xzp)) != 0) {
+			return (error);
+		}
+
+		check_zp = xzp;
+
+		/*
+		 * fixup mode to map to xattr perms
+		 */
+
+		if (mode & (ACE_WRITE_DATA|ACE_APPEND_DATA)) {
+			mode &= ~(ACE_WRITE_DATA|ACE_APPEND_DATA);
+			mode |= ACE_WRITE_NAMED_ATTRS;
+		}
+
+		if (mode & (ACE_READ_DATA|ACE_EXECUTE)) {
+			mode &= ~(ACE_READ_DATA|ACE_EXECUTE);
+			mode |= ACE_READ_NAMED_ATTRS;
+		}
+	}
+
 	owner = zfs_fuid_map_id(zp->z_zfsvfs, zp->z_uid, cr, ZFS_OWNER);
 
 	/*

module/os/freebsd/zfs/zfs_vfsops.c

@@ -1209,6 +1209,8 @@ zfs_set_fuid_feature(zfsvfs_t *zfsvfs)
 	zfsvfs->z_use_sa = USE_SA(zfsvfs->z_version, zfsvfs->z_os);
 }
 
+extern int zfs_xattr_compat;
+
 static int
 zfs_domount(vfs_t *vfsp, char *osname)
 {
@@ -1289,6 +1291,16 @@ zfs_domount(vfs_t *vfsp, char *osname)
 			goto out;
 	}
 
+#if __FreeBSD_version >= 1500040
+	/*
+	 * Named attributes can only work if the xattr property is set to
+	 * on/dir and not sa.  Also, zfs_xattr_compat must be set.
+	 */
+	if ((zfsvfs->z_flags & ZSB_XATTR) != 0 && !zfsvfs->z_xattr_sa &&
+	    zfs_xattr_compat)
+		vfsp->mnt_flag |= MNT_NAMEDATTR;
+#endif
+
 	vfs_mountedfrom(vfsp, osname);
 
 	if (!zfsvfs->z_issnap)
@@ -1812,6 +1824,14 @@ zfs_vget(vfs_t *vfsp, ino_t ino, int flags, vnode_t **vpp)
 		err = vn_lock(*vpp, flags);
 		if (err != 0)
 			vrele(*vpp);
+#if __FreeBSD_version >= 1500040
+		else if ((zp->z_pflags & ZFS_XATTR) != 0) {
+			if ((*vpp)->v_type == VDIR)
+				vn_irflag_set_cond(*vpp, VIRF_NAMEDDIR);
+			else
+				vn_irflag_set_cond(*vpp, VIRF_NAMEDATTR);
+		}
+#endif
 	}
 	if (err != 0)
 		*vpp = NULL;
@@ -1964,9 +1984,17 @@ zfs_fhtovp(vfs_t *vfsp, fid_t *fidp, int flags, vnode_t **vpp)
 	*vpp = ZTOV(zp);
 	zfs_exit(zfsvfs, FTAG);
 	err = vn_lock(*vpp, flags);
-	if (err == 0)
+	if (err == 0) {
 		vnode_create_vobject(*vpp, zp->z_size, curthread);
-	else
+#if __FreeBSD_version >= 1500040
+		if ((zp->z_pflags & ZFS_XATTR) != 0) {
+			if ((*vpp)->v_type == VDIR)
+				vn_irflag_set_cond(*vpp, VIRF_NAMEDDIR);
+			else
+				vn_irflag_set_cond(*vpp, VIRF_NAMEDATTR);
+		}
+#endif
+	} else
 		*vpp = NULL;
 	return (err);
 }