Commit 109e3765 authored by NeilBrown's avatar NeilBrown Committed by Shaohua Li
Browse files

md: add block tracing for bio_remapping 



The block tracing infrastructure (accessed with blktrace/blkparse)
supports the tracing of mapping bios from one device to another.
This is currently used when a bio in a partition is mapped to the
whole device, when bios are mapped by dm, and for mapping in md/raid5.
Other md personalities do not include this tracing yet, so add it.

When a read-error is detected we redirect the request to a different device.
This could justifiably be seen as a new mapping for the originial bio,
or a secondary mapping for the bio that errors.  This patch uses
the second option.

When md is used under dm-raid, the mappings are not traced as we do
not have access to the block device number of the parent.

Signed-off-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 354b445b

drivers/md/linear.c

+12 −6
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/seq_file.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <trace/events/block.h>

#include "md.h"

#include "linear.h"
@@ -227,22 +228,22 @@ static void linear_make_request(struct mddev *mddev, struct bio *bio) 
	}



	do {

		tmp_dev = which_dev(mddev, bio->bi_iter.bi_sector);

		sector_t bio_sector = bio->bi_iter.bi_sector;

		tmp_dev = which_dev(mddev, bio_sector);

		start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;

		end_sector = tmp_dev->end_sector;

		data_offset = tmp_dev->rdev->data_offset;

		bio->bi_bdev = tmp_dev->rdev->bdev;



		if (unlikely(bio->bi_iter.bi_sector >= end_sector ||

			     bio->bi_iter.bi_sector < start_sector))

		if (unlikely(bio_sector >= end_sector ||

			     bio_sector < start_sector))

			goto out_of_bounds;



		if (unlikely(bio_end_sector(bio) > end_sector)) {

			/* This bio crosses a device boundary, so we have to

			 * split it.

			 */

			split = bio_split(bio, end_sector -

					  bio->bi_iter.bi_sector,

			split = bio_split(bio, end_sector - bio_sector,

					  GFP_NOIO, fs_bio_set);

			bio_chain(split, bio);

		} else {
@@ -256,8 +257,13 @@ static void linear_make_request(struct mddev *mddev, struct bio *bio) 
			 !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) {

			/* Just ignore it */

			bio_endio(split);

		} else

		} else {

			if (mddev->gendisk)

				trace_block_bio_remap(bdev_get_queue(split->bi_bdev),

						      split, disk_devt(mddev->gendisk),

						      bio_sector);

			generic_make_request(split);

		}

	} while (split != bio);

	return;

drivers/md/raid0.c

+10 −3
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/seq_file.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <trace/events/block.h>

#include "md.h"

#include "raid0.h"

#include "raid5.h"
@@ -463,7 +464,8 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio) 
	}



	do {

		sector_t sector = bio->bi_iter.bi_sector;

		sector_t bio_sector = bio->bi_iter.bi_sector;

		sector_t sector = bio_sector;

		unsigned chunk_sects = mddev->chunk_sectors;



		unsigned sectors = chunk_sects -
@@ -472,7 +474,7 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio) 
			 : sector_div(sector, chunk_sects));



		/* Restore due to sector_div */

		sector = bio->bi_iter.bi_sector;

		sector = bio_sector;



		if (sectors < bio_sectors(bio)) {

			split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set);
@@ -491,8 +493,13 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio) 
			 !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) {

			/* Just ignore it */

			bio_endio(split);

		} else

		} else {

			if (mddev->gendisk)

				trace_block_bio_remap(bdev_get_queue(split->bi_bdev),

						      split, disk_devt(mddev->gendisk),

						      bio_sector);

			generic_make_request(split);

		}

	} while (split != bio);

}

drivers/md/raid1.c

+24 −2
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include <linux/module.h>

#include <linux/seq_file.h>

#include <linux/ratelimit.h>

#include <trace/events/block.h>

#include "md.h"

#include "raid1.h"

#include "bitmap.h"
@@ -1162,6 +1163,11 @@ read_again: 
		bio_set_op_attrs(read_bio, op, do_sync);

		read_bio->bi_private = r1_bio;



		if (mddev->gendisk)

			trace_block_bio_remap(bdev_get_queue(read_bio->bi_bdev),

					      read_bio, disk_devt(mddev->gendisk),

					      r1_bio->sector);



		if (max_sectors < r1_bio->sectors) {

			/* could not read all from this device, so we will

			 * need another r1_bio.
@@ -1367,13 +1373,20 @@ read_again: 


		mbio->bi_iter.bi_sector	= (r1_bio->sector +

				   conf->mirrors[i].rdev->data_offset);

		mbio->bi_bdev = (void*)conf->mirrors[i].rdev;

		mbio->bi_bdev = conf->mirrors[i].rdev->bdev;

		mbio->bi_end_io	= raid1_end_write_request;

		bio_set_op_attrs(mbio, op, do_flush_fua | do_sync);

		mbio->bi_private = r1_bio;



		atomic_inc(&r1_bio->remaining);



		if (mddev->gendisk)

			trace_block_bio_remap(bdev_get_queue(mbio->bi_bdev),

					      mbio, disk_devt(mddev->gendisk),

					      r1_bio->sector);

		/* flush_pending_writes() needs access to the rdev so...*/

		mbio->bi_bdev = (void*)conf->mirrors[i].rdev;



		cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));

		if (cb)

			plug = container_of(cb, struct raid1_plug_cb, cb);
@@ -2290,6 +2303,8 @@ static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio) 
	struct bio *bio;

	char b[BDEVNAME_SIZE];

	struct md_rdev *rdev;

	dev_t bio_dev;

	sector_t bio_sector;



	clear_bit(R1BIO_ReadError, &r1_bio->state);

	/* we got a read error. Maybe the drive is bad.  Maybe just
@@ -2303,6 +2318,8 @@ static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio) 


	bio = r1_bio->bios[r1_bio->read_disk];

	bdevname(bio->bi_bdev, b);

	bio_dev = bio->bi_bdev->bd_dev;

	bio_sector = conf->mirrors[r1_bio->read_disk].rdev->data_offset + r1_bio->sector;

	bio_put(bio);

	r1_bio->bios[r1_bio->read_disk] = NULL;
@@ -2353,6 +2370,8 @@ read_more: 
			else

				mbio->bi_phys_segments++;

			spin_unlock_irq(&conf->device_lock);

			trace_block_bio_remap(bdev_get_queue(bio->bi_bdev),

					      bio, bio_dev, bio_sector);

			generic_make_request(bio);

			bio = NULL;
@@ -2367,10 +2386,13 @@ read_more: 
				sectors_handled;



			goto read_more;

		} else

		} else {

			trace_block_bio_remap(bdev_get_queue(bio->bi_bdev),

					      bio, bio_dev, bio_sector);

			generic_make_request(bio);

		}

	}

}



static void raid1d(struct md_thread *thread)

{

drivers/md/raid10.c

+29 −2
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/seq_file.h>

#include <linux/ratelimit.h>

#include <linux/kthread.h>

#include <trace/events/block.h>

#include "md.h"

#include "raid10.h"

#include "raid0.h"
@@ -1165,6 +1166,10 @@ read_again: 
		bio_set_op_attrs(read_bio, op, do_sync);

		read_bio->bi_private = r10_bio;



		if (mddev->gendisk)

			trace_block_bio_remap(bdev_get_queue(read_bio->bi_bdev),

					      read_bio, disk_devt(mddev->gendisk),

					      r10_bio->sector);

		if (max_sectors < r10_bio->sectors) {

			/* Could not read all from this device, so we will

			 * need another r10_bio.
@@ -1367,11 +1372,18 @@ retry_write: 
			mbio->bi_iter.bi_sector	= (r10_bio->devs[i].addr+

					   choose_data_offset(r10_bio,

							      rdev));

			mbio->bi_bdev = (void*)rdev;

			mbio->bi_bdev = rdev->bdev;

			mbio->bi_end_io	= raid10_end_write_request;

			bio_set_op_attrs(mbio, op, do_sync | do_fua);

			mbio->bi_private = r10_bio;



			if (conf->mddev->gendisk)

				trace_block_bio_remap(bdev_get_queue(mbio->bi_bdev),

						      mbio, disk_devt(conf->mddev->gendisk),

						      r10_bio->sector);

			/* flush_pending_writes() needs access to the rdev so...*/

			mbio->bi_bdev = (void*)rdev;



			atomic_inc(&r10_bio->remaining);



			cb = blk_check_plugged(raid10_unplug, mddev,
@@ -1409,11 +1421,18 @@ retry_write: 
			mbio->bi_iter.bi_sector	= (r10_bio->devs[i].addr +

					   choose_data_offset(

						   r10_bio, rdev));

			mbio->bi_bdev = (void*)rdev;

			mbio->bi_bdev = rdev->bdev;

			mbio->bi_end_io	= raid10_end_write_request;

			bio_set_op_attrs(mbio, op, do_sync | do_fua);

			mbio->bi_private = r10_bio;



			if (conf->mddev->gendisk)

				trace_block_bio_remap(bdev_get_queue(mbio->bi_bdev),

						      mbio, disk_devt(conf->mddev->gendisk),

						      r10_bio->sector);

			/* flush_pending_writes() needs access to the rdev so...*/

			mbio->bi_bdev = (void*)rdev;



			atomic_inc(&r10_bio->remaining);

			spin_lock_irqsave(&conf->device_lock, flags);

			bio_list_add(&conf->pending_bio_list, mbio);
@@ -2496,6 +2515,8 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio) 
	char b[BDEVNAME_SIZE];

	unsigned long do_sync;

	int max_sectors;

	dev_t bio_dev;

	sector_t bio_last_sector;



	/* we got a read error. Maybe the drive is bad.  Maybe just

	 * the block and we can fix it.
@@ -2507,6 +2528,8 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio) 
	 */

	bio = r10_bio->devs[slot].bio;

	bdevname(bio->bi_bdev, b);

	bio_dev = bio->bi_bdev->bd_dev;

	bio_last_sector = r10_bio->devs[slot].addr + rdev->data_offset + r10_bio->sectors;

	bio_put(bio);

	r10_bio->devs[slot].bio = NULL;
@@ -2546,6 +2569,10 @@ read_more: 
	bio_set_op_attrs(bio, REQ_OP_READ, do_sync);

	bio->bi_private = r10_bio;

	bio->bi_end_io = raid10_end_read_request;

	trace_block_bio_remap(bdev_get_queue(bio->bi_bdev),

			      bio, bio_dev,

			      bio_last_sector - r10_bio->sectors);



	if (max_sectors < r10_bio->sectors) {

		/* Drat - have to split this up more */

		struct bio *mbio = r10_bio->master_bio;

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