+static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
+{
+ char b[BDEVNAME_SIZE];
+
+ if (uptodate) {
+ set_buffer_uptodate(bh);
+ } else {
+ if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
+ printk(KERN_WARNING "lost page write due to "
+ "I/O error on %s\n",
+ bdevname(bh->b_bdev, b));
+ }
+ /* note, we dont' set_buffer_write_io_error because we have
+ * our own ways of dealing with the IO errors
+ */
+ clear_buffer_uptodate(bh);
+ }
+ unlock_buffer(bh);
+ put_bh(bh);
+}
+
+int write_all_supers(struct btrfs_root *root)
+{
+ struct list_head *cur;
+ struct list_head *head = &root->fs_info->fs_devices->devices;
+ struct btrfs_device *dev;
+ struct btrfs_super_block *sb;
+ struct btrfs_dev_item *dev_item;
+ struct buffer_head *bh;
+ int ret;
+ int do_barriers;
+ int max_errors;
+ int total_errors = 0;
+ u32 crc;
+ u64 flags;
+
+ max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
+ do_barriers = !btrfs_test_opt(root, NOBARRIER);
+
+ sb = &root->fs_info->super_for_commit;
+ dev_item = &sb->dev_item;
+ list_for_each(cur, head) {
+ dev = list_entry(cur, struct btrfs_device, dev_list);
+ if (!dev->bdev) {
+ total_errors++;
+ continue;
+ }
+ if (!dev->in_fs_metadata)
+ continue;
+
+ btrfs_set_stack_device_type(dev_item, dev->type);
+ btrfs_set_stack_device_id(dev_item, dev->devid);
+ btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
+ btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
+ btrfs_set_stack_device_io_align(dev_item, dev->io_align);
+ btrfs_set_stack_device_io_width(dev_item, dev->io_width);
+ btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
+ memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
+ flags = btrfs_super_flags(sb);
+ btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
+
+
+ crc = ~(u32)0;
+ crc = btrfs_csum_data(root, (char *)sb + BTRFS_CSUM_SIZE, crc,
+ BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
+ btrfs_csum_final(crc, sb->csum);
+
+ bh = __getblk(dev->bdev, BTRFS_SUPER_INFO_OFFSET / 4096,
+ BTRFS_SUPER_INFO_SIZE);
+
+ memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
+ dev->pending_io = bh;
+
+ get_bh(bh);
+ set_buffer_uptodate(bh);
+ lock_buffer(bh);
+ bh->b_end_io = btrfs_end_buffer_write_sync;
+
+ if (do_barriers && dev->barriers) {
+ ret = submit_bh(WRITE_BARRIER, bh);
+ if (ret == -EOPNOTSUPP) {
+ printk("btrfs: disabling barriers on dev %s\n",
+ dev->name);
+ set_buffer_uptodate(bh);
+ dev->barriers = 0;
+ get_bh(bh);
+ lock_buffer(bh);
+ ret = submit_bh(WRITE, bh);
+ }
+ } else {
+ ret = submit_bh(WRITE, bh);
+ }
+ if (ret)
+ total_errors++;
+ }
+ if (total_errors > max_errors) {
+ printk("btrfs: %d errors while writing supers\n", total_errors);
+ BUG();
+ }
+ total_errors = 0;
+
+ list_for_each(cur, head) {
+ dev = list_entry(cur, struct btrfs_device, dev_list);
+ if (!dev->bdev)
+ continue;
+ if (!dev->in_fs_metadata)
+ continue;
+
+ BUG_ON(!dev->pending_io);
+ bh = dev->pending_io;
+ wait_on_buffer(bh);
+ if (!buffer_uptodate(dev->pending_io)) {
+ if (do_barriers && dev->barriers) {
+ printk("btrfs: disabling barriers on dev %s\n",
+ dev->name);
+ set_buffer_uptodate(bh);
+ get_bh(bh);
+ lock_buffer(bh);
+ dev->barriers = 0;
+ ret = submit_bh(WRITE, bh);
+ BUG_ON(ret);
+ wait_on_buffer(bh);
+ if (!buffer_uptodate(bh))
+ total_errors++;
+ } else {
+ total_errors++;
+ }
+
+ }
+ dev->pending_io = NULL;
+ brelse(bh);
+ }
+ if (total_errors > max_errors) {
+ printk("btrfs: %d errors while writing supers\n", total_errors);
+ BUG();
+ }
+ return 0;
+}
+