eulerfs: add file_operations for dir inode

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I40JRR
CVE: NA

--------------------------------------

Impelement file_operations for dir inode.
Signed-off-by: NMingkai Dong <dongmingkai1@huawei.com>
Signed-off-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NZhikang Zhang <zhangzhikang1@huawei.com>
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/eulerfs/dir.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021. Huawei Technologies Co., Ltd. All rights reserved.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include "euler.h"
+#include "dht.h"
+
+#define DT2IF(dt) (((dt) << 12) & S_IFMT)
+#define IF2DT(sif) (((sif)&S_IFMT) >> 12)
+
+static int dir_emitter(void *privdata, const struct nv_dict_entry *de)
+{
+	struct dir_scan_data *data = (struct dir_scan_data *)privdata;
+	struct eufs_inode *pi;
+	int namelen;
+	const char *name;
+	char *page;
+	int r;
+
+	pi = s2p(data->sb, de->inode);
+	pi = EUFS_FRESH_PI(pi);
+	name = de->name;
+	namelen = HASHLEN_LEN(de->hv);
+
+	eufs_dbg("!de=%px, de->pi=%px, de->nextname=%llx, namelen=%d\n", de,
+		  pi, de->nextname, namelen);
+	if (likely(namelen <= FIRST_LEN)) {
+		eufs_dbg("%s found name: %*s len: %d inode: %px\n",
+			  __func__, namelen, name, namelen, pi);
+
+		r = dir_emit(data->ctx, name, namelen, le64_to_cpu(de->inode),
+			     IF2DT(eufs_iread_mode(pi)));
+		if (!r)
+			return -EINVAL;
+		return 0;
+	}
+	if (eufs_ptr_fast_check_b(de->nextname)) {
+		eufs_info("!de=%px, de->pi=%px, de->nextname=%llx, namelen=%d\n",
+			  de, pi, de->nextname, namelen);
+		BUG();
+	}
+	page = eufs_alloc_name_copy(data->sb, name, namelen,
+				     s2p(data->sb, de->nextname));
+	eufs_dbg("%s found name: %*s len: %d inode: %px\n", __func__, namelen,
+		  page, namelen, pi);
+
+	r = dir_emit(data->ctx, page, namelen, le64_to_cpu(de->inode),
+		     IF2DT(eufs_iread_mode(pi)));
+	eufs_free_page(page);
+	if (!r)
+		return -EINVAL;
+	return 0;
+}
+
+static int eufs_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
+	struct eufs_inode *pi = EUFS_PI(inode);
+	struct dir_scan_data data = { .sb = inode->i_sb, .ctx = ctx };
+
+	if (ctx->pos == EUFS_DIR_EODIR)
+		return 0;
+	if (ctx->pos == 0) {
+		if (!dir_emit(ctx, ".", 1, (u64)eufs_pi2ino(inode->i_sb, pi),
+			      IF2DT(inode->i_mode))) {
+			return -EINVAL;
+		}
+		ctx->pos = EUFS_DIR_DOT;
+	}
+
+	if (ctx->pos == EUFS_DIR_DOT) {
+		struct eufs_inode *dotdot = o2p(
+			inode->i_sb, eufs_iread_dotdot(EUFS_FRESH_PI(pi)));
+
+		if (!dir_emit(ctx, "..", 2,
+			      (u64)eufs_pi2ino(inode->i_sb, dotdot),
+			      IF2DT(eufs_iread_mode(dotdot))))
+			return -EINVAL;
+		ctx->pos = EUFS_DIR_DOTDOT;
+	}
+
+	if (!inode->i_size) {
+		ctx->pos = EUFS_DIR_EODIR;
+		return 0;
+	}
+	eufs_dbg("In Readdir! ctx->pos=%llx  inode=%px, pi=%px\n", ctx->pos,
+		  inode, pi);
+
+	nv_dict_scan_via_ptr(inode, ctx->pos, dir_emitter, (void *)&data);
+
+	eufs_dbg("Out Readdir! ctx->pos=%llx\n", ctx->pos);
+	return 0;
+}
+
+static loff_t eufs_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct inode *inode = file_inode(file);
+	loff_t retval;
+
+	inode_lock(inode);
+	switch (whence) {
+	case SEEK_END:
+		/* TODO */
+		retval = -EINVAL;
+		goto out;
+	case SEEK_CUR:
+		/* TODO */
+		retval = -EINVAL;
+		goto out;
+	case SEEK_SET:
+		break;
+	}
+	if (offset != file->f_pos) {
+		file->f_pos = offset;
+		file->f_version = 0;
+	}
+	retval = offset;
+out:
+	inode_unlock(inode);
+	return retval;
+}
+
+const struct file_operations eufs_dir_operations = {
+	.llseek = eufs_dir_llseek,
+	.read = generic_read_dir,
+	.iterate = eufs_readdir,
+	.fsync = eufs_fsync,
+};