[RFC 1/1] ubi: An interface is added for dump the mapping between LEBs and PEBs

[Zhihao Cheng]

在 2023/7/22 18:23, ZhaoLong Wang 写道:
> A debugfs interface named "detailed_eba_table_info" is added to view
> the PEB and LEB mapping information of all volumes on a UBI device.
> 
> $ cat /sys/kernel/debug/ubi/ubi1/detailed_eba_table_info
> 
> =========   vol_name:"test_volA",id:2   ========
> logical_block_number    physical_block_number
> 0                        274
> 1                        275
> 2                        276
> 3                        277
> 4                        278
> ......
> =========   vol_name:"test_volB",id:3   ========
> logical_block_number    physical_block_number
> 0                        619
> 1                        613
> 2                        614
> 3                       (unmaped)
> 4                        622
> ......
> 
> Signed-off-by: ZhaoLong Wang <wangzhaolong1 at huawei.com>
> ---
>   drivers/mtd/ubi/debug.c | 104 ++++++++++++++++++++++++++++++++++++++++
>   drivers/mtd/ubi/eba.c   |  24 ----------
>   drivers/mtd/ubi/ubi.h   |  24 ++++++++++
>   3 files changed, 128 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
> index 27168f511d6d..c6be9450b509 100644
> --- a/drivers/mtd/ubi/debug.c
> +++ b/drivers/mtd/ubi/debug.c
> @@ -386,6 +386,7 @@ static const struct file_operations dfs_fops = {
>   	.owner  = THIS_MODULE,
>   };
>   
> +
>   /* As long as the position is less then that total number of erase blocks,
>    * we still have more to print.
>    */
> @@ -493,6 +494,106 @@ static const struct file_operations eraseblk_count_fops = {
>   	.release = eraseblk_count_release,
>   };
>   
> +static void *eba_table_seq_start(struct seq_file *s, loff_t *pos)
> +{
> +	int volumes_length = UBI_MAX_VOLUMES + UBI_INT_VOL_COUNT;
> +
> +	if (*pos >= 0 && *pos < volumes_length)
> +		return pos;
> +
> +	return NULL;
> +}
> +
> +static void *eba_table_seq_next(struct seq_file *s, void *v, loff_t *pos)
> +{
> +	int volumes_length = UBI_MAX_VOLUMES + UBI_INT_VOL_COUNT;
> +
> +	(*pos)++;
> +
> +	if (*pos >= 0 && *pos < volumes_length)
> +		return pos;
> +
> +	return NULL;
> +}
> +
> +static void eba_table_seq_stop(struct seq_file *s, void *v)
> +{
> +}
> +
> +static int eba_table_seq_show(struct seq_file *s, void *iter)
> +{
> +	struct ubi_device *ubi = s->private;
> +	int *vol_idx  = iter;
> +	struct ubi_volume *vol;
> +	int lnum, pnum, vol_id;
> +
> +	vol = ubi->volumes[*vol_idx];
> +	if (vol == NULL)
> +		return 0;
> +
> +	vol_id = vol->vol_id;
> +	seq_printf(s, "=========   vol_name:\"%s\",id:%d   ========\n", vol->name, vol_id);
> +	seq_puts(s, "logical_block_number\tphysical_block_number\n");
> +	spin_lock(&ubi->volumes_lock);
> +	for (lnum = 0; lnum < vol->reserved_pebs; ++lnum) {
> +		pnum = vol->eba_tbl->entries[lnum].pnum;
> +		if (pnum >= 0)
> +			seq_printf(s, "%-22d\t %-11d\n", lnum, pnum);
> +		else
> +			seq_printf(s, "%-22d\t(unmaped)\n", lnum);
> +	}
> +	spin_unlock(&ubi->volumes_lock);
> +
> +	return 0;
> +}

Mote, this traversal of 'vol->eba_tbl->entries' depends on 
https://patchwork.ozlabs.org/project/linux-mtd/patch/20230504025354.3595768-1-wangzhaolong1@huawei.com/.

Reviewed-by: Zhihao Cheng <chengzhihao1 at huawei.com>

> +
> +static const struct seq_operations eba_table_seq_ops = {
> +	.start = eba_table_seq_start,
> +	.next = eba_table_seq_next,
> +	.stop = eba_table_seq_stop,
> +	.show = eba_table_seq_show
> +};
> +
> +static int eba_table_open(struct inode *inode, struct file *f)
> +{
> +	struct seq_file *s;
> +	int err;
> +
> +	err = seq_open(f, &eba_table_seq_ops);
> +	if (err)
> +		return err;
> +
> +	s = f->private_data;
> +	s->private = ubi_get_device((unsigned long)inode->i_private);
> +
> +	if (!s->private)
> +		return -ENODEV;
> +	else
> +		return 0;
> +}
> +
> +static int eba_table_release(struct inode *inode, struct file *f)
> +{
> +	struct seq_file *s = f->private_data;
> +	struct ubi_device *ubi = s->private;
> +
> +	ubi_put_device(ubi);
> +
> +	return seq_release(inode, f);
> +}
> +
> +/* File operations for UBI debugfs files which to read
> + * eba_tbl to help developer get the map status of ubi
> + * volumes
> + */
> +static const struct file_operations eba_table_fops = {
> +	.owner = THIS_MODULE,
> +	.open = eba_table_open,
> +	.read = seq_read,
> +	.llseek = no_llseek,
> +	.release = eba_table_release,
> +};
> +
>   /**
>    * ubi_debugfs_init_dev - initialize debugfs for an UBI device.
>    * @ubi: UBI device description object
> @@ -556,6 +657,9 @@ int ubi_debugfs_init_dev(struct ubi_device *ubi)
>   						   mode, d->dfs_dir,
>   						   (void *)ubi_num, &dfs_fops);
>   
> +	debugfs_create_file("detailed_eba_table_info", S_IRUSR, d->dfs_dir,
> +			    (void *)ubi_num, &eba_table_fops);
> +
>   	debugfs_create_file("detailed_erase_block_info", S_IRUSR, d->dfs_dir,
>   			    (void *)ubi_num, &eraseblk_count_fops);
>   
> diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
> index 655ff41863e2..c856ea73a67c 100644
> --- a/drivers/mtd/ubi/eba.c
> +++ b/drivers/mtd/ubi/eba.c
> @@ -36,30 +36,6 @@
>   /* Number of physical eraseblocks reserved for atomic LEB change operation */
>   #define EBA_RESERVED_PEBS 1
>   
> -/**
> - * struct ubi_eba_entry - structure encoding a single LEB -> PEB association
> - * @pnum: the physical eraseblock number attached to the LEB
> - *
> - * This structure is encoding a LEB -> PEB association. Note that the LEB
> - * number is not stored here, because it is the index used to access the
> - * entries table.
> - */
> -struct ubi_eba_entry {
> -	int pnum;
> -};
> -
> -/**
> - * struct ubi_eba_table - LEB -> PEB association information
> - * @entries: the LEB to PEB mapping (one entry per LEB).
> - *
> - * This structure is private to the EBA logic and should be kept here.
> - * It is encoding the LEB to PEB association table, and is subject to
> - * changes.
> - */
> -struct ubi_eba_table {
> -	struct ubi_eba_entry *entries;
> -};
> -
>   /**
>    * ubi_next_sqnum - get next sequence number.
>    * @ubi: UBI device description object
> diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
> index c8f1bd4fa100..1457657901df 100644
> --- a/drivers/mtd/ubi/ubi.h
> +++ b/drivers/mtd/ubi/ubi.h
> @@ -153,6 +153,30 @@ enum {
>   	POWER_CUT_VID_WRITE = 0x02,
>   };
>   
> +/**
> + * struct ubi_eba_entry - structure encoding a single LEB -> PEB association
> + * @pnum: the physical eraseblock number attached to the LEB
> + *
> + * This structure is encoding a LEB -> PEB association. Note that the LEB
> + * number is not stored here, because it is the index used to access the
> + * entries table.
> + */
> +struct ubi_eba_entry {
> +	int pnum;
> +};
> +
> +/**
> + * struct ubi_eba_table - LEB -> PEB association information
> + * @entries: the LEB to PEB mapping (one entry per LEB).
> + *
> + * This structure is private to the EBA logic and should be kept here.
> + * It is encoding the LEB to PEB association table, and is subject to
> + * changes.
> + */
> +struct ubi_eba_table {
> +	struct ubi_eba_entry *entries;
> +};
> +
>   /**
>    * struct ubi_vid_io_buf - VID buffer used to read/write VID info to/from the
>    *			   flash.
>