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: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 9ac61cd..2dc193492 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -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 @@ static void raid1_make_request(struct mddev *mddev, struct bio * bio)
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 @@ static void raid1_make_request(struct mddev *mddev, struct bio * bio)
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 @@ static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
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;
@@ -2367,8 +2386,11 @@ static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
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);
+ }
}
}