Hi,
I've noticed that Arne's scrub patches add scrub variables directly
into the fs_info structure, while you have a separate struct.
I was wondering whether it would be better to put items of
btrfs_balance_info to fs_info too, balance state is a global info.
Although fs_info is a huge structure now, 9402 bytes on 86_64, there is
no space saving in this case.
On Sun, Apr 10, 2011 at 10:06:04PM +0100, Hugo Mills wrote:
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 7f78cc7..17c7ecc 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -865,6 +865,11 @@ struct btrfs_block_group_cache {
> struct list_head cluster_list;
> };
>
> +struct btrfs_balance_info {
> + u32 expected;
> + u32 completed;
two u32 make one u64
> +};
> +
> struct reloc_control;
> struct btrfs_device;
> struct btrfs_fs_devices;
> @@ -1078,6 +1083,10 @@ struct btrfs_fs_info {
>
> /* filesystem state */
> u64 fs_state;
> +
> + /* Keep track of any rebalance operations on this FS */
> + spinlock_t balance_info_lock;
> + struct btrfs_balance_info *balance_info;
a pointer is a u64 too
> };
>
> /*
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index dd13eb8..bb2ffed 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -2051,6 +2052,20 @@ int btrfs_balance(struct btrfs_root *dev_root)
> mutex_lock(&dev_root->fs_info->volume_mutex);
> dev_root = dev_root->fs_info->dev_root;
>
> + bal_info = kmalloc(
> + sizeof(struct btrfs_balance_info),
> + GFP_NOFS);
... drop
> + if (!bal_info) {
> + ret = -ENOMEM;
> + goto error_no_status;
> + }
> + spin_lock(&dev_root->fs_info->balance_info_lock);
> + dev_root->fs_info->balance_info = bal_info;
> + bal_info->expected = -1; /* One less than actually counted,
> + because chunk 0 is special */
> + bal_info->completed = 0;
> + spin_unlock(&dev_root->fs_info->balance_info_lock);
> +
> /* step one make some room on all the devices */
> list_for_each_entry(device, devices, dev_list) {
> old_size = device->total_bytes;
> @@ -2115,10 +2157,20 @@ int btrfs_balance(struct btrfs_root *dev_root)
> found_key.offset);
> BUG_ON(ret && ret != -ENOSPC);
> key.offset = found_key.offset - 1;
> + spin_lock(&dev_root->fs_info->balance_info_lock);
> + bal_info->completed++;
> + spin_unlock(&dev_root->fs_info->balance_info_lock);
> + printk(KERN_INFO "btrfs: balance: %llu/%llu block groups completed\n",
> + bal_info->completed, bal_info->expected);
> }
> ret = 0;
> error:
> btrfs_free_path(path);
> + spin_lock(&dev_root->fs_info->balance_info_lock);
> + kfree(dev_root->fs_info->balance_info);
... drop
> + dev_root->fs_info->balance_info = NULL;
> + spin_unlock(&dev_root->fs_info->balance_info_lock);
> +error_no_status:
> mutex_unlock(&dev_root->fs_info->volume_mutex);
> return ret;
> }
> --
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