[PATCH v5 4/4] btrfs-progs: image: fix restored image size misalignment

[Qu Wenruo <wqu@suse.com>]

[BUG]
There is a small device size misalignment between the super block device
size and the device extent size:
total_bytes             10737418240 	<<<
bytes_used              15097856
dev_item.total_bytes    10737418240
dev_item.bytes_used     1094713344

        item 0 key (DEV_ITEMS DEV_ITEM 1) itemoff 16185 itemsize 98
                devid 1 total_bytes 1095761920 bytes_used 1094713344
				    ^^^^^^^^^^

[CAUSE]
In fixup_device_size(), we only reset superblock device item size, which
will be overwritten in write_dev_supers() using
btrfs_device::total_bytes.

And it doesn't touch btrfs_superblock::total_bytes either.

[FIX]
So fix the small mismatch by also resetting btrfs_device::total_bytes,
btrfs_device::bytes_used and btrfs_superblock::total_bytes.

Thankfully since commit 73dd4e3c87c9 ("btrfs-progs: image: Don't modify
the chunk and device tree if the source dump is single device") single
device dump won't have such problem, but it's still worthy for
multi-device dump.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 image/main.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/image/main.c b/image/main.c
index 5fa6fa5aba17..42564b1d2f44 100644
--- a/image/main.c
+++ b/image/main.c
@@ -2374,6 +2374,7 @@ static int fixup_device_size(struct btrfs_trans_handle *trans,
 	struct btrfs_fs_info *fs_info = trans->fs_info;
 	struct btrfs_dev_item *dev_item;
 	struct btrfs_dev_extent *dev_ext;
+	struct btrfs_device *dev;
 	struct btrfs_path path;
 	struct extent_buffer *leaf;
 	struct btrfs_root *root = fs_info->chunk_root;
@@ -2392,6 +2393,8 @@ static int fixup_device_size(struct btrfs_trans_handle *trans,
 	key.type = BTRFS_DEV_EXTENT_KEY;
 	key.offset = (u64)-1;
 
+	dev = list_first_entry(&fs_info->fs_devices->devices,
+				struct btrfs_device, dev_list);
 	ret = btrfs_search_slot(NULL, fs_info->dev_root, &key, &path, 0, 0);
 	if (ret < 0) {
 		errno = -ret;
@@ -2425,6 +2428,9 @@ static int fixup_device_size(struct btrfs_trans_handle *trans,
 
 	btrfs_set_stack_device_total_bytes(dev_item, dev_size);
 	btrfs_set_stack_device_bytes_used(dev_item, mdres->alloced_chunks);
+	dev->total_bytes = dev_size;
+	dev->bytes_used = mdres->alloced_chunks;
+	btrfs_set_super_total_bytes(fs_info->super_copy, dev_size);
 	ret = fstat(out_fd, &buf);
 	if (ret < 0) {
 		error("failed to stat result image: %m");
-- 
2.29.2