Re: [PATCH 1/4] Btrfs: fix wrong send_in_progress accounting

[Wang Shilong <wangsl.fnst@cn.fujitsu.com>]

On 01/07/2014 12:30 AM, David Sterba wrote:
> On Mon, Jan 06, 2014 at 05:25:06PM +0800, Wang Shilong wrote:
>> Steps to reproduce:
>>
>>   # mkfs.btrfs -f /dev/sda8
>>   # mount /dev/sda8 /mnt
>>   # btrfs sub snapshot -r /mnt /mnt/snap1
>>   # btrfs sub snapshot -r /mnt /mnt/snap2
>>   # btrfs send /mnt/snap2 -p /mnt/snap1
>>
>> As @send_root will also add into clone_sources, and we should
>> take care not to decrease its count twice.
> Yes, send_root is appended to the clone_roots but the
> clone_sources_to_rollback does not track this, it's not updated after
> it's added in
>
>    sctx->clone_roots[sctx->clone_roots_cnt++].root = sctx->send_root;
>
> so send->root->send_in_progress is not modified in the loop that
> decrements all clone_root's counters again.
>
> I don't see the warning that should catch negative values of the counter
> in btrfs_root_dec_send_in_progress. Am I missing something?
just run 'dmesg' after the above commands.

Thanks,
Wang
>
>
> david
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