Hi Yunlong, I think you have changed original implication of the function, IMO, it would be more accurate to use user_free_segment_blocks instead of free_user_blocks. Thanks, On 2017/8/18 18:02, Yunlong Song wrote: > ping... > > On 2017/8/15 15:14, Yunlong Song wrote: >> The part (overprovision_segments - reserved_segments) can still be used for LFS >> in some case, e.g., there are lots of invalid block from dirty segments, then >> the part (overprovision_segments - reserved_segments) can be safely used. So >> free_use_blocks should use reserved_segments instead, rather than directly use >> overprovision_segments. BTW, we also add the constraint of sbi->reserved_blocks. >> >> Signed-off-by: Yunlong Song <yunlong.song@xxxxxxxxxx> >> --- >> fs/f2fs/gc.h | 18 +++++++++++++++--- >> 1 file changed, 15 insertions(+), 3 deletions(-) >> >> diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h >> index 9325191..542612a 100644 >> --- a/fs/f2fs/gc.h >> +++ b/fs/f2fs/gc.h >> @@ -49,11 +49,23 @@ struct gc_inode_list { >> */ >> static inline block_t free_user_blocks(struct f2fs_sb_info *sbi) >> { >> - if (free_segments(sbi) < overprovision_segments(sbi)) >> + block_t avail_user_block_count, free_blocks, avail_free_blocks; >> + block_t reserved_blocks; >> + >> + avail_user_block_count = sbi->user_block_count - sbi->reserved_blocks; >> + >> + if (unlikely(sbi->total_valid_block_count > avail_user_block_count)) >> + return 0; >> + >> + free_blocks = free_segments(sbi) << sbi->log_blocks_per_seg; >> + avail_free_blocks = min(free_blocks, avail_user_block_count - >> + sbi->total_valid_block_count); >> + reserved_blocks = reserved_segments(sbi) << sbi->log_blocks_per_seg; >> + >> + if (avail_free_blocks < reserved_blocks) >> return 0; >> else >> - return (free_segments(sbi) - overprovision_segments(sbi)) >> - << sbi->log_blocks_per_seg; >> + return avail_free_blocks - reserved_blocks; >> } >> static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info *sbi) >