btrfs: output mirror number for bad metadata

When handling a real world transid mismatch image, it's hard to know
which copy is corrupted, as the error messages just look like this:

  BTRFS warning (device dm-3): checksum verify failed on 30408704 wanted 0xcdcdcdcd found 0x3c0adc8e level 0
  BTRFS warning (device dm-3): checksum verify failed on 30408704 wanted 0xcdcdcdcd found 0x3c0adc8e level 0
  BTRFS warning (device dm-3): checksum verify failed on 30408704 wanted 0xcdcdcdcd found 0x3c0adc8e level 0
  BTRFS warning (device dm-3): checksum verify failed on 30408704 wanted 0xcdcdcdcd found 0x3c0adc8e level 0

We don't even know if the retry is caused by btrfs or the VFS retry.

To make things a little easier to read, add mirror number for all
related tree block read errors.

So the above messages would look like this:

  BTRFS warning (device dm-3): checksum verify failed on logical 30408704 mirror 1 wanted 0xcdcdcdcd found 0x3c0adc8e level 0
  BTRFS warning (device dm-3): checksum verify failed on logical 30408704 mirror 2 wanted 0xcdcdcdcd found 0x3c0adc8e level 0
  BTRFS warning (device dm-3): checksum verify failed on logical 30408704 mirror 1 wanted 0xcdcdcdcd found 0x3c0adc8e level 0
  BTRFS warning (device dm-3): checksum verify failed on logical 30408704 mirror 2 wanted 0xcdcdcdcd found 0x3c0adc8e level 0
Signed-off-by: Qu Wenruo <wqu@suse.com>
[ update messages, add "logical" ]
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

@@ -221,8 +221,8 @@ static int verify_parent_transid(struct extent_io_tree *io_tree,
 		goto out;
 	}
 	btrfs_err_rl(eb->fs_info,
-		"parent transid verify failed on %llu wanted %llu found %llu",
-			eb->start,
+"parent transid verify failed on logical %llu mirror %u wanted %llu found %llu",
+			eb->start, eb->read_mirror,
 			parent_transid, btrfs_header_generation(eb));
 	ret = 1;
 	clear_extent_buffer_uptodate(eb);
@@ -552,21 +552,23 @@ static int validate_extent_buffer(struct extent_buffer *eb)
 
 	found_start = btrfs_header_bytenr(eb);
 	if (found_start != eb->start) {
-		btrfs_err_rl(fs_info, "bad tree block start, want %llu have %llu",
-			     eb->start, found_start);
+		btrfs_err_rl(fs_info,
+			"bad tree block start, mirror %u want %llu have %llu",
+			     eb->read_mirror, eb->start, found_start);
 		ret = -EIO;
 		goto out;
 	}
 	if (check_tree_block_fsid(eb)) {
-		btrfs_err_rl(fs_info, "bad fsid on block %llu",
-			     eb->start);
+		btrfs_err_rl(fs_info, "bad fsid on logical %llu mirror %u",
+			     eb->start, eb->read_mirror);
 		ret = -EIO;
 		goto out;
 	}
 	found_level = btrfs_header_level(eb);
 	if (found_level >= BTRFS_MAX_LEVEL) {
-		btrfs_err(fs_info, "bad tree block level %d on %llu",
-			  (int)btrfs_header_level(eb), eb->start);
+		btrfs_err(fs_info,
+			"bad tree block level, mirror %u level %d on logical %llu",
+			eb->read_mirror, btrfs_header_level(eb), eb->start);
 		ret = -EIO;
 		goto out;
 	}
@@ -577,8 +579,8 @@ static int validate_extent_buffer(struct extent_buffer *eb)
 
 	if (memcmp(result, header_csum, csum_size) != 0) {
 		btrfs_warn_rl(fs_info,
-	"checksum verify failed on %llu wanted " CSUM_FMT " found " CSUM_FMT " level %d",
-			      eb->start,
+"checksum verify failed on logical %llu mirror %u wanted " CSUM_FMT " found " CSUM_FMT " level %d",
+			      eb->start, eb->read_mirror,
 			      CSUM_FMT_VALUE(csum_size, header_csum),
 			      CSUM_FMT_VALUE(csum_size, result),
 			      btrfs_header_level(eb));
@@ -603,8 +605,8 @@ static int validate_extent_buffer(struct extent_buffer *eb)
 		set_extent_buffer_uptodate(eb);
 	else
 		btrfs_err(fs_info,
-			  "block=%llu read time tree block corruption detected",
-			  eb->start);
+		"read time tree block corruption detected on logical %llu mirror %u",
+			  eb->start, eb->read_mirror);
 out:
 	return ret;
 }