Messages in this thread | | | Subject | Re: [f2fs-dev] [PATCH v4] f2fs: introduce fragment allocation mode mount option | From | Chao Yu <> | Date | Fri, 10 Sep 2021 07:50:57 +0800 |
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On 2021/9/8 2:12, Daeho Jeong wrote: > On Fri, Sep 3, 2021 at 11:45 PM Chao Yu <chao@kernel.org> wrote: >> >> On 2021/9/4 12:40, Daeho Jeong wrote: >>>> As a per curseg field. >>>> >>>>> Maybe, we run into the same race condition issue you told before for >>>>> fragment_remained_chunk. >>>>> Could you clarify this more? >>>> >>>> e.g. >>>> >>>> F2FS_OPTION(sbi).fs_mode = FS_MODE_FRAGMENT_FIXED_BLK >>>> fragment_chunk_size = 384 >>>> fragment_hole_size = 384 >>>> >>>> When creating hole: >>>> >>>> - f2fs_allocate_data_block >>>> - __refresh_next_blkoff >>>> chunk locates in [0, 383] of current segment >>>> seg->next_blkoff = 384 >>>> sbi->fragment_remained_chunk = 0 >>>> then we will reset sbi->fragment_remained_chunk to 384 >>>> and move seg->next_blkoff forward to 768 (384 + 384) >>>> - __has_curseg_space() returns false >>>> - allocate_segment() allocates new current segment >>>> >>>> So, for such case that hole may cross two segments, hole size may be truncated >>>> to left size of previous segment. >>> >>> First, sbi->fragment_remained_chunk should be seg->fragment_remained_chunk. >> >> Oh, correct. >> >>> I understand what you mean, so you mean we need to take the leftover >>> "hole" size over to the next segment? >>> In the example, the leftover hole size will be (384 - (512-384)). Do >>> you want to take this over to the next segment? >> >> Yes, the left 256 block-sized hole should be created before next chunk >> in next opened segment. >> > > Chao, > > Do you have any decent idea to pass the left hole size to the next > segment which will be allocated?
Daeho,
I guess we can record left hole size in seg->fragment_remained_hole.
Thanks,
> > Thanks, > >> Thanks, >> >>>
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