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f2fs: fix to avoid touching checkpointed data in get_victim()

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[ Upstream commit 61461fc921b756ae16e64243f72af2bfc2e620db ]

In CP disabling mode, there are two issues when using LFS or SSR | AT_SSR
mode to select victim:

1. LFS is set to find source section during GC, the victim should have
no checkpointed data, since after GC, section could not be set free for
reuse.

Previously, we only check valid chpt blocks in current segment rather
than section, fix it.

2. SSR | AT_SSR are set to find target segment for writes which can be
fully filled by checkpointed and newly written blocks, we should never
select such segment, otherwise it can cause panic or data corruption
during allocation, potential case is described as below:

 a) target segment has 'n' (n < 512) ckpt valid blocks
 b) GC migrates 'n' valid blocks to other segment (segment is still
    in dirty list)
 c) GC migrates '512 - n' blocks to target segment (segment has 'n'
    cp_vblocks and '512 - n' vblocks)
 d) If GC selects target segment via {AT,}SSR allocator, however there
    is no free space in targe segment.

Fixes: 4354994f09 ("f2fs: checkpoint disabling")
Fixes: 093749e296 ("f2fs: support age threshold based garbage collection")
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Chao Yu
2021-03-24 11:18:28 +08:00
committed by Greg Kroah-Hartman
parent bbed83d706
commit 105155a814
4 changed files with 55 additions and 24 deletions
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14
fs/f2fs/segment.h
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@@ -361,8 +361,20 @@ static inline unsigned int get_valid_blocks(struct f2fs_sb_info *sbi,
}
static inline unsigned int get_ckpt_valid_blocks(struct f2fs_sb_info *sbi,
unsigned int segno)
unsigned int segno, bool use_section)
{
if (use_section && __is_large_section(sbi)) {
unsigned int start_segno = START_SEGNO(segno);
unsigned int blocks = 0;
int i;
for (i = 0; i < sbi->segs_per_sec; i++, start_segno++) {
struct seg_entry *se = get_seg_entry(sbi, start_segno);
blocks += se->ckpt_valid_blocks;
}
return blocks;
}
return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
}