v4.19.13 snapshot.
diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
new file mode 100644
index 0000000..3b66c95
--- /dev/null
+++ b/fs/btrfs/acl.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007 Red Hat. All rights reserved.
+ */
+
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/posix_acl.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include "ctree.h"
+#include "btrfs_inode.h"
+#include "xattr.h"
+
+struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
+{
+ int size;
+ const char *name;
+ char *value = NULL;
+ struct posix_acl *acl;
+
+ switch (type) {
+ case ACL_TYPE_ACCESS:
+ name = XATTR_NAME_POSIX_ACL_ACCESS;
+ break;
+ case ACL_TYPE_DEFAULT:
+ name = XATTR_NAME_POSIX_ACL_DEFAULT;
+ break;
+ default:
+ return ERR_PTR(-EINVAL);
+ }
+
+ size = btrfs_getxattr(inode, name, NULL, 0);
+ if (size > 0) {
+ value = kzalloc(size, GFP_KERNEL);
+ if (!value)
+ return ERR_PTR(-ENOMEM);
+ size = btrfs_getxattr(inode, name, value, size);
+ }
+ if (size > 0)
+ acl = posix_acl_from_xattr(&init_user_ns, value, size);
+ else if (size == -ENODATA || size == 0)
+ acl = NULL;
+ else
+ acl = ERR_PTR(size);
+ kfree(value);
+
+ return acl;
+}
+
+static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
+ struct inode *inode, struct posix_acl *acl, int type)
+{
+ int ret, size = 0;
+ const char *name;
+ char *value = NULL;
+
+ switch (type) {
+ case ACL_TYPE_ACCESS:
+ name = XATTR_NAME_POSIX_ACL_ACCESS;
+ break;
+ case ACL_TYPE_DEFAULT:
+ if (!S_ISDIR(inode->i_mode))
+ return acl ? -EINVAL : 0;
+ name = XATTR_NAME_POSIX_ACL_DEFAULT;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (acl) {
+ size = posix_acl_xattr_size(acl->a_count);
+ value = kmalloc(size, GFP_KERNEL);
+ if (!value) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
+ if (ret < 0)
+ goto out;
+ }
+
+ ret = btrfs_setxattr(trans, inode, name, value, size, 0);
+out:
+ kfree(value);
+
+ if (!ret)
+ set_cached_acl(inode, type, acl);
+
+ return ret;
+}
+
+int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+ int ret;
+ umode_t old_mode = inode->i_mode;
+
+ if (type == ACL_TYPE_ACCESS && acl) {
+ ret = posix_acl_update_mode(inode, &inode->i_mode, &acl);
+ if (ret)
+ return ret;
+ }
+ ret = __btrfs_set_acl(NULL, inode, acl, type);
+ if (ret)
+ inode->i_mode = old_mode;
+ return ret;
+}
+
+int btrfs_init_acl(struct btrfs_trans_handle *trans,
+ struct inode *inode, struct inode *dir)
+{
+ struct posix_acl *default_acl, *acl;
+ int ret = 0;
+
+ /* this happens with subvols */
+ if (!dir)
+ return 0;
+
+ ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
+ if (ret)
+ return ret;
+
+ if (default_acl) {
+ ret = __btrfs_set_acl(trans, inode, default_acl,
+ ACL_TYPE_DEFAULT);
+ posix_acl_release(default_acl);
+ }
+
+ if (acl) {
+ if (!ret)
+ ret = __btrfs_set_acl(trans, inode, acl,
+ ACL_TYPE_ACCESS);
+ posix_acl_release(acl);
+ }
+
+ if (!default_acl && !acl)
+ cache_no_acl(inode);
+ return ret;
+}