Re: [PATCH 0/3] introduce type based delalloc metadata reserve to fix some false enospc issues

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

Hi Stefan,

I'm trying to push it to for-next (will be v4.11), but no response yet.

It would be quite nice for you to test the following git pull and give 
some feedback, so that we can merge it faster.

https://mail-archive.com/linux-btrfs@vger.kernel.org/msg60418.html

Thanks,
Qu

On 12/31/2016 03:31 PM, Stefan Priebe - Profihost AG wrote:
> Any news on this series? I can't see it in 4.9 nor in 4.10-rc
>
> Stefan
>
> Am 11.11.2016 um 09:39 schrieb Wang Xiaoguang:
>> When having compression enabled, Stefan Priebe ofen got enospc errors
>> though fs still has much free space. Qu Wenruo also has submitted a
>> fstests test case which can reproduce this bug steadily, please see
>> url: https://patchwork.kernel.org/patch/9420527
>>
>> First patch[1/3] "btrfs: improve inode's outstanding_extents computation" is to
>> fix outstanding_extents and reserved_extents account issues. This issue was revealed
>> by modifying BTRFS_MAX_EXTENT_SIZE(128MB) to 64KB, When modifying
>> BTRFS_MAX_EXTENT_SIZE(128MB) to 64KB, fsstress test often gets these warnings from
>> btrfs_destroy_inode():
>>         WARN_ON(BTRFS_I(inode)->outstanding_extents);
>>         WARN_ON(BTRFS_I(inode)->reserved_extents);
>> Please see this patch's commit message for detailed info, and this patch is
>> necessary to patch2 and patch3.
>>
>> For false enospc, the root reasson is that for compression, its max extent size will
>> be 128k, not 128MB. If we still use 128MB as max extent size to reserve metadata for
>> compression, obviously it's not appropriate. In patch "btrfs: Introduce COMPRESS
>> reserve type to fix false enospc for compression" commit message,
>> we explain why false enospc error occurs, please see it for detailed info.
>>
>> To fix this issue, we introduce a new enum type:
>> 	enum btrfs_metadata_reserve_type {
>> 		BTRFS_RESERVE_NORMAL,
>>         	BTRFS_RESERVE_COMPRESS,
>> 	};
>> For btrfs_delalloc_[reserve|release]_metadata() and
>> btrfs_delalloc_[reserve|release]_space(), we introce a new btrfs_metadata_reserve_type
>> argument, then if a path needs to go compression, we pass BTRFS_RESERVE_COMPRESS,
>> otherwise pass BTRFS_RESERVE_NORMAL.
>>
>> With these patchs, Stefan no longer saw such false enospc errors, and Qu Wenruo's
>> fstests test case will also pass. I have also run whole fstests multiple times,
>> no regression occurs, thanks.
>>
>> Wang Xiaoguang (3):
>>   btrfs: improve inode's outstanding_extents computation
>>   btrfs: introduce type based delalloc metadata reserve
>>   btrfs: Introduce COMPRESS reserve type to fix false enospc for
>>     compression
>>
>>  fs/btrfs/ctree.h             |  36 +++++--
>>  fs/btrfs/extent-tree.c       |  52 ++++++---
>>  fs/btrfs/extent_io.c         |  61 ++++++++++-
>>  fs/btrfs/extent_io.h         |   5 +
>>  fs/btrfs/file.c              |  25 +++--
>>  fs/btrfs/free-space-cache.c  |   6 +-
>>  fs/btrfs/inode-map.c         |   6 +-
>>  fs/btrfs/inode.c             | 246 ++++++++++++++++++++++++++++++++++---------
>>  fs/btrfs/ioctl.c             |  16 +--
>>  fs/btrfs/relocation.c        |  14 ++-
>>  fs/btrfs/tests/inode-tests.c |  15 +--
>>  11 files changed, 381 insertions(+), 101 deletions(-)
>>
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