Lots of quotation removed. All removed comments accepted.
On 16.06.2011 23:27, David Sterba wrote:
> On Mon, Jun 13, 2011 at 09:10:39PM +0200, Jan Schmidt wrote:
>> +struct scrub_fixup_nodatasum {
>> + struct scrub_dev *sdev;
>> + u64 logical;
>> + struct btrfs_root *root;
>> + struct btrfs_work work;
>> + u64 mirror_num;
>
> int should be enough and is used elsewhere but scrub_page, uses u64 as well;
> that's a bit too much IMO
You are right. scrub.c should be changed to use int mirror_num all over.
I'll integrate a cleanup patch in my next patch series as patch 6/7 and
this one can become a clean 7/7 then.
>> +};
>> +
>> struct scrub_warning {
>> struct btrfs_path *path;
>> u64 extent_item_size;
>> @@ -195,12 +205,13 @@ struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
>>
>> if (i != SCRUB_BIOS_PER_DEV-1)
>> sdev->bios[i]->next_free = i + 1;
>> - else
>> + else
>> sdev->bios[i]->next_free = -1;
>> }
>> sdev->first_free = 0;
>> sdev->curr = -1;
>> atomic_set(&sdev->in_flight, 0);
>> + atomic_set(&sdev->fixup, 0);
>> atomic_set(&sdev->cancel_req, 0);
>> sdev->csum_size = btrfs_super_csum_size(&fs_info->super_copy);
>> INIT_LIST_HEAD(&sdev->csum_list);
>> @@ -330,6 +341,141 @@ out:
>> kfree(swarn.msg_buf);
>> }
>>
>> +static int scrub_fixup_readpage(u64 inum, loff_t offset, void *ctx)
>> +{
>> + struct page *page;
>> + unsigned long index;
>> + struct scrub_fixup_nodatasum *fixup = ctx;
>> + int ret;
>> + int corrected;
>> + struct btrfs_key key;
>> + struct inode *inode;
>> + int end = offset + PAGE_SIZE - 1;
>
> loff_t to int?
>
>> +
>> + key.type = BTRFS_INODE_ITEM_KEY;
>> + key.objectid = inum;
>> + key.offset = 0;
>> + inode = btrfs_iget(fixup->root->fs_info->sb, &key,
>> + fixup->root->fs_info->fs_root, NULL);
>> + if (IS_ERR(inode))
>> + return -1;
>
> needs better error code
>
>> +
>> + ret = set_extent_bit(&BTRFS_I(inode)->io_tree, offset, end,
>> + EXTENT_DAMAGED, 0, NULL, NULL, GFP_NOFS);
>> + if (ret)
>> + return ret < 0 ? ret : -1;
>
> needs better error code
Hum. That one is tricky. set_extent_bit can in theory return anything,
as there is at least one hook that can be called. If it returns
non-zero, that will become the return value of set_extent_bit. As far as
I see, that hook will always return 0 at the moment. In case that hook
decides to return something >0, I still want iterate_extent_inodes() to
terminate iteration. I think adding a WARN_ON for that and returning
-EFAULT is an option.
>> /*
>> - * nodatasum, don't try to fix anything
>> - * FIXME: we can do better, open the inode and trigger a
>> - * writeback
>> + * increment scrubs_running to prevent cancel requests from
>> + * completing as long as a fixup worker is running. we must also
>> + * increment scrubs_paused to prevent deadlocking on pause
>> + * requests used for transactions commits (as the worker uses a
>> + * transaction context). it is safe to regard the fixup worker
>> + * as paused for all matters practical. effectively, we only
>> + * avoid cancellation requests from completing.
>
> from a rather brief look, this works as advertised
>
>> */
Bonus points for thinking about that :-)
Thanks!
Jan
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