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[PATCH] UBI: add debugfs file for tracking PEB state

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  [PATCH] UBI: add debugfs file for tracking PEB state Zach Brown <zach.brown@ni.com> - 2016-09-19 20:50 +0200
    Re: [PATCH] UBI: add debugfs file for tracking PEB state Richard Weinberger <richard@nod.at> - 2016-09-19 21:10 +0200
    Re: [PATCH] UBI: add debugfs file for tracking PEB state kbuild test robot <lkp@intel.com> - 2016-09-19 21:50 +0200

#1486761 — [PATCH] UBI: add debugfs file for tracking PEB state

From: Ben Shelton <ben.shelton@ni.com>

Add a file under debugfs to allow easy access to the erase count for
each physical erase block on an UBI device.  This is useful when
debugging data integrity issues with UBIFS on NAND flash devices.

Signed-off-by: Ben Shelton <ben.shelton@ni.com>
Signed-off-by: Zach Brown <zach.brown@ni.com>
---
 drivers/mtd/ubi/debug.c | 151 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 150 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
index f101a49..09eaab6 100644
--- a/drivers/mtd/ubi/debug.c
+++ b/drivers/mtd/ubi/debug.c
@@ -22,6 +22,7 @@
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/module.h>
+#include <linux/seq_file.h>
 
 
 /**
@@ -386,7 +387,9 @@ out:
 	return count;
 }
 
-/* File operations for all UBI debugfs files */
+/* File operations for all UBI debugfs files except
+ * detailed_erase_block_info
+ */
 static const struct file_operations dfs_fops = {
 	.read   = dfs_file_read,
 	.write  = dfs_file_write,
@@ -395,6 +398,146 @@ 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.
+ */
+static void *eraseblk_count_seq_start(struct seq_file *s, loff_t *pos)
+{
+	struct ubi_device *ubi = s->private;
+
+	if (*pos == 0)
+		return SEQ_START_TOKEN;
+
+	if (*pos < ubi->peb_count)
+		return pos;
+
+	return NULL;
+}
+
+/* Since we are using the position as the iterator, we just need to check if we
+ * are done and increment the position.
+ */
+static void *eraseblk_count_seq_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	struct ubi_device *ubi = s->private;
+
+	if (v == SEQ_START_TOKEN)
+		return pos;
+	(*pos)++;
+
+	if (*pos < ubi->peb_count)
+		return pos;
+
+	return NULL;
+}
+
+static void eraseblk_count_seq_stop(struct seq_file *s, void *v)
+{
+}
+
+enum block_status {
+	BLOCK_STATUS_OK,
+	BLOCK_STATUS_BAD_BLOCK,
+	BLOCK_STATUS_ERASE_COUNT_BEYOND_MAX
+};
+
+static char const *block_status_names[] = {"OK", "marked_bad",
+					   "erase_count_beyond_max"};
+
+enum read_status {
+	READ_STATUS_OK,
+	READ_STATUS_ERR_READING_BLOCK,
+	READ_STATUS_ERR_READING_ERASE_COUNT
+};
+
+static char const *read_status_names[] = {"OK", "err_reading_block",
+					  "err_reading_erase_count"};
+
+static int eraseblk_count_seq_show(struct seq_file *s, void *iter)
+{
+	struct ubi_device *ubi = s->private;
+	int *block_number = iter;
+	int erase_count = -1;
+	enum block_status b_sts = BLOCK_STATUS_OK;
+	enum read_status r_sts = READ_STATUS_OK;
+	int err;
+
+	/* If this is the start, print a header */
+	if (iter == SEQ_START_TOKEN) {
+		seq_puts(s,
+			 "physical_block_number\terase_count\tblock_status\tread_status\n");
+		return 0;
+	}
+
+	err = ubi_io_is_bad(ubi, *block_number);
+	if (err) {
+		if (err < 0)
+			r_sts = READ_STATUS_ERR_READING_BLOCK;
+		else
+			b_sts = BLOCK_STATUS_BAD_BLOCK;
+	} else {
+		struct ubi_ec_hdr erase_count_header;
+
+		err = ubi_io_read_ec_hdr(ubi, *block_number,
+					 &erase_count_header, 0);
+		if (err && err != UBI_IO_BITFLIPS)
+			r_sts = READ_STATUS_ERR_READING_ERASE_COUNT;
+		else {
+			erase_count = be64_to_cpu(erase_count_header.ec);
+			if (erase_count > UBI_MAX_ERASECOUNTER)
+				b_sts = BLOCK_STATUS_ERASE_COUNT_BEYOND_MAX;
+		}
+	}
+
+	seq_printf(s, "%-22d\t%-11d\t%-12s\t%-12s\n", *block_number,
+		   erase_count, block_status_names[b_sts],
+		   read_status_names[r_sts]);
+	return 0;
+}
+
+static const struct seq_operations eraseblk_count_seq_ops = {
+	.start = eraseblk_count_seq_start,
+	.next = eraseblk_count_seq_next,
+	.stop = eraseblk_count_seq_stop,
+	.show = eraseblk_count_seq_show
+};
+
+static int eraseblk_count_open(struct inode *inode, struct file *f)
+{
+	struct seq_file *s;
+	int err;
+
+	err = seq_open(f, &eraseblk_count_seq_ops);
+	if (err)
+		return err;
+
+	s = f->private_data;
+	s->private = ubi_get_device((int)inode->i_private);
+
+	if (!s->private)
+		return -ENODEV;
+	else
+		return 0;
+}
+
+static int eraseblk_count_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);
+}
+
+static const struct file_operations eraseblk_count_fops = {
+	.owner = THIS_MODULE,
+	.open = eraseblk_count_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = eraseblk_count_release,
+};
+
 /**
  * ubi_debugfs_init_dev - initialize debugfs for an UBI device.
  * @ubi: UBI device description object
@@ -491,6 +634,12 @@ int ubi_debugfs_init_dev(struct ubi_device *ubi)
 		goto out_remove;
 	d->dfs_power_cut_max = dent;
 
+	fname = "detailed_erase_block_info";
+	dent = debugfs_create_file(fname, S_IRUSR, d->dfs_dir, (void *)ubi_num,
+				   &eraseblk_count_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+
 	return 0;
 
 out_remove:
-- 
2.7.4

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#1486775

Zach,

On 19.09.2016 20:47, Zach Brown wrote:
> +	} else {
> +		struct ubi_ec_hdr erase_count_header;
> +
> +		err = ubi_io_read_ec_hdr(ubi, *block_number,
> +					 &erase_count_header, 0);
> +		if (err && err != UBI_IO_BITFLIPS)
> +			r_sts = READ_STATUS_ERR_READING_ERASE_COUNT;
> +		else {
> +			erase_count = be64_to_cpu(erase_count_header.ec);
> +			if (erase_count > UBI_MAX_ERASECOUNTER)
> +				b_sts = BLOCK_STATUS_ERASE_COUNT_BEYOND_MAX;

Hmm, why don't you use ubi->lookuptbl[] to get a ubi_wl_entry object, it knows
the erase counter. That way you don't have to read from the flash. If you read
you have to deal with all kind of read errors, including bitflips.

Thanks,
//richard

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#1486803

[Multipart message — attachments visible in raw view] — view raw

Hi Ben,

[auto build test WARNING on mtd/master]
[also build test WARNING on v4.8-rc7 next-20160919]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
[Suggest to use git(>=2.9.0) format-patch --base=<commit> (or --base=auto for convenience) to record what (public, well-known) commit your patch series was built on]
[Check https://git-scm.com/docs/git-format-patch for more information]

url:    https://github.com/0day-ci/linux/commits/Zach-Brown/UBI-add-debugfs-file-for-tracking-PEB-state/20160920-025147
base:   git://git.infradead.org/linux-mtd.git master
config: x86_64-randconfig-i0-201638 (attached as .config)
compiler: gcc-4.9 (Debian 4.9.4-2) 4.9.4
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   drivers/mtd/ubi/debug.c: In function 'eraseblk_count_open':
>> drivers/mtd/ubi/debug.c:515:30: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
     s->private = ubi_get_device((int)inode->i_private);
                                 ^

vim +515 drivers/mtd/ubi/debug.c

   499		.start = eraseblk_count_seq_start,
   500		.next = eraseblk_count_seq_next,
   501		.stop = eraseblk_count_seq_stop,
   502		.show = eraseblk_count_seq_show
   503	};
   504	
   505	static int eraseblk_count_open(struct inode *inode, struct file *f)
   506	{
   507		struct seq_file *s;
   508		int err;
   509	
   510		err = seq_open(f, &eraseblk_count_seq_ops);
   511		if (err)
   512			return err;
   513	
   514		s = f->private_data;
 > 515		s->private = ubi_get_device((int)inode->i_private);
   516	
   517		if (!s->private)
   518			return -ENODEV;
   519		else
   520			return 0;
   521	}
   522	
   523	static int eraseblk_count_release(struct inode *inode, struct file *f)

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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