1 files changed, 152 insertions, 0 deletions
diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
new file mode 100644
index 000000000..5810463dc
--- /dev/null
+++ b/fs/btrfs/acl.c
@@ -0,0 +1,152 @@
+// 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/sched/mm.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) {
+		unsigned int nofs_flag;
+
+		size = posix_acl_xattr_size(acl->a_count);
+		/*
+		 * We're holding a transaction handle, so use a NOFS memory
+		 * allocation context to avoid deadlock if reclaim happens.
+		 */
+		nofs_flag = memalloc_nofs_save();
+		value = kmalloc(size, GFP_KERNEL);
+		memalloc_nofs_restore(nofs_flag);
+		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;
+}