fsck.ubifs: Add fsck support

Add basic process code for fsck.ubifs. There are following modes for fsck:
 1. normal mode: Check the filesystem, ask user whether or not to fix
    the problem as long as inconsistent data is found during fs checking.
 2. safe mode: Check and safely repair the filesystem, if there are any
    data dropping operations needed by fixing, fsck will fail.
 3. danger mode: Answer 'yes' to all questions. There two sub modes:
    a) Check and repair the filesystem according to TNC, data dropping
       will be reported. If TNC/master/log is corrupted, fsck will fail.
    b) Check and forcedly repair the filesystem according to TNC, turns
       to rebuild filesystem if TNC/master/log is corrupted. Always make
       fsck succeed.
 4. check mode: Make no changes to the filesystem, only check the
    filesystem.
 5. rebuild mode: Scan entire UBI volume to find all nodes, and rebuild
    filesystem, always make fsck success.

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

4 files changed, 67 insertions, 3 deletions

diff --git a/ubifs-utils/libubifs/budget.c b/ubifs-utils/libubifs/budget.c
index 54392a9..5550c9a 100644
--- a/ubifs-utils/libubifs/budget.c
+++ b/ubifs-utils/libubifs/budget.c
@@ -201,7 +201,7 @@ long long ubifs_calc_available(const struct ubifs_info *c, int min_idx_lebs)
 static int can_use_rp(__unused struct ubifs_info *c)
 {
 	/* Fsck can always use reserved pool. */
-	return c->program_type != MKFS_PROGRAM_TYPE;
+	return c->program_type == FSCK_PROGRAM_TYPE;
 }
 
 /**
diff --git a/ubifs-utils/libubifs/debug.c b/ubifs-utils/libubifs/debug.c
index a210990..94928da 100644
--- a/ubifs-utils/libubifs/debug.c
+++ b/ubifs-utils/libubifs/debug.c
@@ -1021,7 +1021,11 @@ void ubifs_assert_failed(struct ubifs_info *c, const char *expr,
 
 	/*
 	 * Different from linux kernel.
-	 * There is only one action(readonly) when assertion is failed.
+	 * Invoke callback function if there is one, otherwise make filesystem
+	 * readonly when assertion is failed.
 	 */
-	ubifs_ro_mode(c, -EINVAL);
+	if (c->assert_failed_cb)
+		c->assert_failed_cb(c);
+	else
+		ubifs_ro_mode(c, -EINVAL);
 }
diff --git a/ubifs-utils/libubifs/super.c b/ubifs-utils/libubifs/super.c
index 9fa366f..155489d 100644
--- a/ubifs-utils/libubifs/super.c
+++ b/ubifs-utils/libubifs/super.c
@@ -138,6 +138,53 @@ int close_target(struct ubifs_info *c)
 }
 
 /**
+ * ubifs_open_volume - open UBI volume.
+ * @c: the UBIFS file-system description object
+ * @volume_name: the UBI volume name
+ *
+ * Open ubi volume. This function is implemented by open_ubi + open_target.
+ *
+ * Returns %0 in case of success and a negative error code in case of failure.
+ */
+int ubifs_open_volume(struct ubifs_info *c, const char *volume_name)
+{
+	int err;
+
+	err = open_ubi(c, volume_name);
+	if (err) {
+		ubifs_err(c, "cannot open libubi. %s", strerror(errno));
+		return err;
+	}
+
+	err = open_target(c);
+	if (err)
+		close_ubi(c);
+
+	return err;
+}
+
+/**
+ * ubifs_close_volume - close UBI volume.
+ * @c: the UBIFS file-system description object
+ *
+ * Close ubi volume. This function is implemented by close_target + close_ubi.
+ *
+ * Returns %0 in case of success and a negative error code in case of failure.
+ */
+int ubifs_close_volume(struct ubifs_info *c)
+{
+	int err;
+
+	err = close_target(c);
+	if (err)
+		return err;
+
+	close_ubi(c);
+
+	return 0;
+}
+
+/**
  * check_volume_empty - check if the UBI volume is empty.
  * @c: the UBIFS file-system description object
  *
@@ -197,6 +244,11 @@ void init_ubifs_info(struct ubifs_info *c, int program_type)
 	case MKFS_PROGRAM_TYPE:
 		c->program_name = MKFS_PROGRAM_NAME;
 		break;
+	case FSCK_PROGRAM_TYPE:
+		c->program_name = FSCK_PROGRAM_NAME;
+		/* Always check crc for data node. */
+		c->no_chk_data_crc = 0;
+		break;
 	default:
 		assert(0);
 		break;
diff --git a/ubifs-utils/libubifs/ubifs.h b/ubifs-utils/libubifs/ubifs.h
index 2af9d87..babaae8 100644
--- a/ubifs-utils/libubifs/ubifs.h
+++ b/ubifs-utils/libubifs/ubifs.h
@@ -1026,6 +1026,9 @@ struct ubifs_budg_info {
  *
  * @new_ihead_lnum: used by debugging to check @c->ihead_lnum
  * @new_ihead_offs: used by debugging to check @c->ihead_offs
+ *
+ * @private: private information related to specific situation, eg. fsck.
+ * @assert_failed_cb: callback function to handle assertion failure
  */
 struct ubifs_info {
 	struct ubifs_sb_node *sup_node;
@@ -1248,6 +1251,9 @@ struct ubifs_info {
 
 	int new_ihead_lnum;
 	int new_ihead_offs;
+
+	void *private;
+	void (*assert_failed_cb)(const struct ubifs_info *c);
 };
 
 extern atomic_long_t ubifs_clean_zn_cnt;
@@ -1684,6 +1690,8 @@ int open_ubi(struct ubifs_info *c, const char *node);
 void close_ubi(struct ubifs_info *c);
 int open_target(struct ubifs_info *c);
 int close_target(struct ubifs_info *c);
+int ubifs_open_volume(struct ubifs_info *c, const char *volume_name);
+int ubifs_close_volume(struct ubifs_info *c);
 int check_volume_empty(struct ubifs_info *c);
 void init_ubifs_info(struct ubifs_info *c, int program_type);
 int init_constants_early(struct ubifs_info *c);