On 2020/5/1 上午9:05, Stephen Rothwell wrote:
> Hi all,
>
> On Fri, 1 May 2020 10:24:53 +1000 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>>
>> Today's linux-next merge of the btrfs tree got a conflict in:
>>
>> fs/btrfs/transaction.c
>>
>> between commit:
>>
>> fcc99734d1d4 ("btrfs: transaction: Avoid deadlock due to bad initialization timing of fs_info::journal_info")
>>
>> from the btrfs-fixes tree and commit:
>>
>> f12ca53a6fd6 ("btrfs: force chunk allocation if our global rsv is larger than metadata")
>>
>> from the btrfs tree.
>>
>> I fixed it up (see below) and can carry the fix as necessary. This
>> is now fixed as far as linux-next is concerned, but any non trivial
>> conflicts should be mentioned to your upstream maintainer when your tree
>> is submitted for merging. You may also want to consider cooperating
>> with the maintainer of the conflicting tree to minimise any particularly
>> complex conflicts.
>>
>> --
>> Cheers,
>> Stephen Rothwell
>>
>> diff --cc fs/btrfs/transaction.c
>> index 2d5498136e5e,e4dbd8e3c641..000000000000
>> --- a/fs/btrfs/transaction.c
>> +++ b/fs/btrfs/transaction.c
>> @@@ -666,15 -674,17 +672,26 @@@ got_it
>> current->journal_info = h;
>>
>> /*
>> + * btrfs_record_root_in_trans() needs to alloc new extents, and may
>> + * call btrfs_join_transaction() while we're also starting a
>> + * transaction.
>> + *
>> + * Thus it need to be called after current->journal_info initialized,
>> + * or we can deadlock.
>> + */
>> + btrfs_record_root_in_trans(h, root);
>> +
>> + * If the space_info is marked ALLOC_FORCE then we'll get upgraded to
>> + * ALLOC_FORCE the first run through, and then we won't allocate for
>> + * anybody else who races in later. We don't care about the return
>> + * value here.
>> + */
>> + if (do_chunk_alloc && num_bytes) {
>> + u64 flags = h->block_rsv->space_info->flags;
>> + btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags),
>> + CHUNK_ALLOC_NO_FORCE);
>> + }
>> +
>> return h;
The proper fix has landed in David's misc-next branch, which puts
btrfs_record_root_in_trans(); after the if () {} code block.
By that, btrfs_record_root_in_trans() has lesser chance to hit ENOSPC.
Thanks,
Qu
>>
>> join_fail:
>
>
> I fixed the missing comment start in my resolution ...
>
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