Messages in this thread | | | Subject | Re: [f2fs-dev] [PATCH v4] f2fs: introduce fragment allocation mode mount option | From | Chao Yu <> | Date | Sat, 4 Sep 2021 14:45:09 +0800 |
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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.
Thanks,
>
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