fsck.ubifs: Load filesystem information from UBI volume

Load filesystem information from UBI volume (Similar to UBIFS mounting
process), initialize kinds of buffers and read superblock. This is the
base step for both fsck and rebuild_fs. Subsequent pacthes will complete
this step by adding more steps(eg. read master, replay journal, etc.)
which are only used in fsck.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 127 insertions, 0 deletions

diff --git a/ubifs-utils/fsck.ubifs/load_fs.c b/ubifs-utils/fsck.ubifs/load_fs.c
new file mode 100644
index 0000000..4a06b4c
--- /dev/null
+++ b/ubifs-utils/fsck.ubifs/load_fs.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024, Huawei Technologies Co, Ltd.
+ *
+ * Authors: Zhihao Cheng <chengzhihao1@huawei.com>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "bitops.h"
+#include "kmem.h"
+#include "ubifs.h"
+#include "defs.h"
+#include "debug.h"
+#include "key.h"
+#include "misc.h"
+#include "fsck.ubifs.h"
+
+int ubifs_load_filesystem(struct ubifs_info *c)
+{
+	int err;
+	size_t sz;
+
+	err = init_constants_early(c);
+	if (err) {
+		exit_code |= FSCK_ERROR;
+		return err;
+	}
+
+	err = check_volume_empty(c);
+	if (err <= 0) {
+		exit_code |= FSCK_ERROR;
+		log_err(c, 0, "%s UBI volume!", err < 0 ? "bad" : "empty");
+		return -EINVAL;
+	}
+
+	if (c->ro_media && !c->ro_mount) {
+		exit_code |= FSCK_ERROR;
+		log_err(c, 0, "cannot read-write on read-only media");
+		return -EROFS;
+	}
+
+	err = -ENOMEM;
+	c->bottom_up_buf = kmalloc_array(BOTTOM_UP_HEIGHT, sizeof(int),
+					 GFP_KERNEL);
+	if (!c->bottom_up_buf) {
+		exit_code |= FSCK_ERROR;
+		log_err(c, errno, "cannot allocate bottom_up_buf");
+		goto out_free;
+	}
+
+	c->sbuf = vmalloc(c->leb_size);
+	if (!c->sbuf) {
+		exit_code |= FSCK_ERROR;
+		log_err(c, errno, "cannot allocate sbuf");
+		goto out_free;
+	}
+
+	if (!c->ro_mount) {
+		c->ileb_buf = vmalloc(c->leb_size);
+		if (!c->ileb_buf) {
+			exit_code |= FSCK_ERROR;
+			log_err(c, errno, "cannot allocate ileb_buf");
+			goto out_free;
+		}
+	}
+
+	c->mounting = 1;
+
+	log_out(c, "Read superblock");
+	err = ubifs_read_superblock(c);
+	if (err) {
+		if (test_and_clear_failure_reason_callback(c, FR_DATA_CORRUPTED))
+			fix_problem(c, SB_CORRUPTED);
+		exit_code |= FSCK_ERROR;
+		goto out_mounting;
+	}
+
+	err = init_constants_sb(c);
+	if (err) {
+		exit_code |= FSCK_ERROR;
+		goto out_mounting;
+	}
+
+	sz = ALIGN(c->max_idx_node_sz, c->min_io_size) * 2;
+	c->cbuf = kmalloc(sz, GFP_NOFS);
+	if (!c->cbuf) {
+		err = -ENOMEM;
+		exit_code |= FSCK_ERROR;
+		log_err(c, errno, "cannot allocate cbuf");
+		goto out_mounting;
+	}
+
+	err = alloc_wbufs(c);
+	if (err) {
+		exit_code |= FSCK_ERROR;
+		log_err(c, 0, "cannot allocate wbuf");
+		goto out_mounting;
+	}
+
+	c->mounting = 0;
+
+	return 0;
+
+out_mounting:
+	c->mounting = 0;
+out_free:
+	kfree(c->cbuf);
+	kfree(c->ileb_buf);
+	kfree(c->sbuf);
+	kfree(c->bottom_up_buf);
+	kfree(c->sup_node);
+
+	return err;
+}
+
+void ubifs_destroy_filesystem(struct ubifs_info *c)
+{
+	free_wbufs(c);
+
+	kfree(c->cbuf);
+	kfree(c->ileb_buf);
+	kfree(c->sbuf);
+	kfree(c->bottom_up_buf);
+	kfree(c->sup_node);
+}