diff options
| author | Chao Yu <yuchao0@huawei.com> | 2018-04-25 19:38:17 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-22 11:45:15 +0200 |
| commit | 2a18f941bccbb3669e3f8f7262f15d7f5267aa0f (patch) | |
| tree | 184e48da8f82e91abcdba2aeeffe51a9f4eea484 /fs | |
| parent | fd2c76451453747d6bdcf7e45c90c1ffe931861c (diff) | |
f2fs: fix potential overflow
commit a9af3fdcc4258af406879eca63d82e9d6baa892e upstream.
In build_sit_entries(), if valid_blocks in SIT block is smaller than
valid_blocks in journal, for below calculation:
sbi->discard_blks += old_valid_blocks - se->valid_blocks;
There will be two times potential overflow:
- old_valid_blocks - se->valid_blocks will overflow, and be a very
large number.
- sbi->discard_blks += result will overflow again, comes out a correct
result accidently.
Anyway, it should be fixed.
Fixes: d600af236da5 ("f2fs: avoid unneeded loop in build_sit_entries")
Fixes: 1f43e2ad7bff ("f2fs: introduce CP_TRIMMED_FLAG to avoid unneeded discard")
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/f2fs/segment.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 2cd0d126ef8f..4307f8db6c8f 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -3337,14 +3337,17 @@ static int build_sit_entries(struct f2fs_sb_info *sbi) } else { memcpy(se->discard_map, se->cur_valid_map, SIT_VBLOCK_MAP_SIZE); - sbi->discard_blks += old_valid_blocks - - se->valid_blocks; + sbi->discard_blks += old_valid_blocks; + sbi->discard_blks -= se->valid_blocks; } } - if (sbi->segs_per_sec > 1) + if (sbi->segs_per_sec > 1) { get_sec_entry(sbi, start)->valid_blocks += - se->valid_blocks - old_valid_blocks; + se->valid_blocks; + get_sec_entry(sbi, start)->valid_blocks -= + old_valid_blocks; + } } up_read(&curseg->journal_rwsem); |