btrfs: scrub: fix incorrectly reported logical/physical address

[BUG]
Scrub is not reporting the correct logical/physical address, it can be
verified by the following script:

 # mkfs.btrfs -f $dev1
 # mount $dev1 $mnt
 # xfs_io -f -c "pwrite -S 0xaa 0 128k" $mnt/file1
 # umount $mnt
 # xfs_io -f -c "pwrite -S 0xff 13647872 4k" $dev1
 # mount $dev1 $mnt
 # btrfs scrub start -fB $mnt
 # umount $mnt

Note above 13647872 is the physical address for logical 13631488 + 4K.

Scrub would report the following error:

 BTRFS error (device dm-2): unable to fixup (regular) error at logical 13631488 on dev /dev/mapper/test-scratch1 physical 13631488
 BTRFS warning (device dm-2): checksum error at logical 13631488 on dev /dev/mapper/test-scratch1, physical 13631488, root 5, inode 257, offset 0, length 4096, links 1 (path: file1)

On the other hand, "btrfs check --check-data-csum" is reporting the
correct logical/physical address:

 Checking filesystem on /dev/test/scratch1
 UUID: db2eb621-b09d-4f24-8199-da17dc7b3201
 [5/7] checking csums against data
 mirror 1 bytenr 13647872 csum 0x13fec125 expected csum 0x656bd64e
 ERROR: errors found in csum tree

[CAUSE]
In the function scrub_stripe_report_errors(), we always use the
stripe->logical and its physical address to print the error message, not
taking the sector number into consideration at all.

[FIX]
Fix the error reporting function by calculating logical/physical with
the sector number.

Now the scrub report is correct:

 BTRFS error (device dm-2): unable to fixup (regular) error at logical 13647872 on dev /dev/mapper/test-scratch1 physical 13647872
 BTRFS warning (device dm-2): checksum error at logical 13647872 on dev /dev/mapper/test-scratch1, physical 13647872, root 5, inode 257, offset 16384, length 4096, links 1 (path: file1)

Fixes: 0096580 ("btrfs: scrub: introduce error reporting functionality for scrub_stripe")
CC: [email protected] #6.4+
Reviewed-by: Anand Jain <[email protected]>
Reviewed-by: Filipe Manana <[email protected]>
Signed-off-by: Qu Wenruo <[email protected]>
Signed-off-by: David Sterba <[email protected]>

fs/btrfs/scrub.c

@@ -870,7 +870,7 @@ static void scrub_stripe_report_errors(struct scrub_ctx *sctx,
 				      DEFAULT_RATELIMIT_BURST);
 	struct btrfs_fs_info *fs_info = sctx->fs_info;
 	struct btrfs_device *dev = NULL;
-	u64 physical = 0;
+	u64 stripe_physical = stripe->physical;
 	int nr_data_sectors = 0;
 	int nr_meta_sectors = 0;
 	int nr_nodatacsum_sectors = 0;
@@ -903,13 +903,17 @@ static void scrub_stripe_report_errors(struct scrub_ctx *sctx,
 		 */
 		if (ret < 0)
 			goto skip;
-		physical = bioc->stripes[stripe_index].physical;
+		stripe_physical = bioc->stripes[stripe_index].physical;
 		dev = bioc->stripes[stripe_index].dev;
 		btrfs_put_bioc(bioc);
 	}
 
 skip:
 	for_each_set_bit(sector_nr, &stripe->extent_sector_bitmap, stripe->nr_sectors) {
+		const u64 logical = stripe->logical +
+				    (sector_nr << fs_info->sectorsize_bits);
+		const u64 physical = stripe_physical +
+				     (sector_nr << fs_info->sectorsize_bits);
 		bool repaired = false;
 
 		if (stripe->sectors[sector_nr].is_metadata) {
@@ -938,12 +942,12 @@ static void scrub_stripe_report_errors(struct scrub_ctx *sctx,
 			if (dev) {
 				btrfs_err_rl_in_rcu(fs_info,
 			"fixed up error at logical %llu on dev %s physical %llu",
-					    stripe->logical, btrfs_dev_name(dev),
+					    logical, btrfs_dev_name(dev),
 					    physical);
 			} else {
 				btrfs_err_rl_in_rcu(fs_info,
 			"fixed up error at logical %llu on mirror %u",
-					    stripe->logical, stripe->mirror_num);
+					    logical, stripe->mirror_num);
 			}
 			continue;
 		}
@@ -952,26 +956,26 @@ static void scrub_stripe_report_errors(struct scrub_ctx *sctx,
 		if (dev) {
 			btrfs_err_rl_in_rcu(fs_info,
 	"unable to fixup (regular) error at logical %llu on dev %s physical %llu",
-					    stripe->logical, btrfs_dev_name(dev),
+					    logical, btrfs_dev_name(dev),
 					    physical);
 		} else {
 			btrfs_err_rl_in_rcu(fs_info,
 	"unable to fixup (regular) error at logical %llu on mirror %u",
-					    stripe->logical, stripe->mirror_num);
+					    logical, stripe->mirror_num);
 		}
 
 		if (test_bit(sector_nr, &stripe->io_error_bitmap))
 			if (__ratelimit(&rs) && dev)
 				scrub_print_common_warning("i/o error", dev, false,
-						     stripe->logical, physical);
+						     logical, physical);
 		if (test_bit(sector_nr, &stripe->csum_error_bitmap))
 			if (__ratelimit(&rs) && dev)
 				scrub_print_common_warning("checksum error", dev, false,
-						     stripe->logical, physical);
+						     logical, physical);
 		if (test_bit(sector_nr, &stripe->meta_error_bitmap))
 			if (__ratelimit(&rs) && dev)
 				scrub_print_common_warning("header error", dev, false,
-						     stripe->logical, physical);
+						     logical, physical);
 	}
 
 	spin_lock(&sctx->stat_lock);