On 8/2/16 6:42 PM, Dave Chinner wrote:
> On Sun, Jul 31, 2016 at 09:19:00PM +0200, Christoph Hellwig wrote:
>> Now after spending this much time I've started wondering why we even
>> reserve blocks in xfs_iomap_write_allocate - after all we've reserved
>> space for the actual data blocks and the indlen worst case in
>> xfs_bmapi_reserve_delalloc. And in fact a little hack to drop that
>> reservation seems to solve both the root cause (depleted reserved pool)
>> and the cleanup mess. I just haven't spend enought time to convince
>> myself that it's actually safe, and in fact looking at the allocator
>> makes me thing it only works by accident currently despite generally
>> postive test results.
>>
>> Here is the quick patch if anyone wants to chime in:
>>
>> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
>> index 620fc91..67c317f 100644
>> --- a/fs/xfs/xfs_iomap.c
>> +++ b/fs/xfs/xfs_iomap.c
>> @@ -717,7 +717,7 @@ xfs_iomap_write_allocate(
>>
>> nimaps = 0;
>> while (nimaps == 0) {
>> - nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
>> + nres = 0; // XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
>>
>> error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, nres,
>> 0, XFS_TRANS_RESERVE, &tp);
>>
>
> This solves the problem for me, and from history appears to be the
> right thing to do. Christoph, can you send a proper patch for this?
Did anything ever come of this? I don't think I saw a patch, and it looks
like it is not upstream.
Thanks,
-Eric
> Cheers,
>
> Dave.
>
