Messages in this thread | | | From | Daeho Jeong <> | Date | Tue, 7 Sep 2021 11:12:21 -0700 | Subject | Re: [f2fs-dev] [PATCH v4] f2fs: introduce fragment allocation mode mount option |
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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?
Thanks,
> Thanks, > > >
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