On 02/12, guoweichao wrote: > > > On 2018/2/12 10:32, Jaegeuk Kim wrote: > > On 02/12, guoweichao wrote: > >> Hi Jaegeuk, > >> > >> On 2018/2/12 7:32, Jaegeuk Kim wrote: > >>> On 02/06, Weichao Guo wrote: > >>>> There is a potential inconsistent metadata case due to a cp block > >>>> crc invalid in the latest checkpoint caused by hardware issues: > >>>> 1) write nodes into segment x; > >>>> 2) write checkpoint A; > >>>> 3) remove nodes in segment x; > >>>> 4) write checkpoint B; > >>>> 5) issue discard or write datas into segment x; > >>>> 6) sudden power-cut; > >>>> 7) use checkpoint A after reboot as checkpoint B is invalid > >>>> > >>>> This inconsistency may be found after several reboots long time later > >>>> and the kernel log about cp block crc invalid has disappeared. This > >>>> makes the root cause of the inconsistency is hard to locate. Let us > >>>> separate such other part issues from f2fs logical bugs in debug version. > >>>> > >>>> Signed-off-by: Weichao Guo <guoweic...@huawei.com> > >>>> --- > >>>> fs/f2fs/checkpoint.c | 8 ++++++-- > >>>> 1 file changed, 6 insertions(+), 2 deletions(-) > >>>> > >>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > >>>> index 8b0945b..16ba96a 100644 > >>>> --- a/fs/f2fs/checkpoint.c > >>>> +++ b/fs/f2fs/checkpoint.c > >>>> @@ -737,13 +737,17 @@ static int get_checkpoint_version(struct > >>>> f2fs_sb_info *sbi, block_t cp_addr, > >>>> crc_offset = le32_to_cpu((*cp_block)->checksum_offset); > >>>> if (crc_offset > (blk_size - sizeof(__le32))) { > >>>> f2fs_msg(sbi->sb, KERN_WARNING, > >>>> - "invalid crc_offset: %zu", crc_offset); > >>>> + "invalid crc_offset: %zu at blk_addr: 0x%x", > >>>> + crc_offset, cp_addr); > >>>> + f2fs_bug_on(sbi, 1); > >>> > >>> I don't think we can use bug_on here, since we're easily getting this when > >>> power-cut happened in the middle of checkpoint pack writes, which is an > >>> expected > >>> behavior. Hmm, we need to consider another way to detect that. > >> We only check CP block crc here. The two CP blocks may have different CP > >> versions when > >> power-cut happened, but their crc value should be valid. IMO, this patch > >> will trigger a > >> bug_on only when some external issues cause CP block crc invalid as one 4K > >> page is > >> persisted atomically. > > > > Huh? This checks crc_offset, not crc? Unfortunately, my simple fault > > injection > > test gave this bug_on within a day. The below bug_on seems what you're > > saying > > about tho. > oh sorry, I didn't notice the code line carefully. But which fault injection > trigger > this bug_on? The crc_offset is also parts of the CP block, it seems power-cut > happened > in middle of writing checkpoint should not produce an invalid crc_offset.
The second cp block can have stale data used by previous part of checkpoint. > > Thanks, > > > > >> > >> Thanks, > >>> > >>> Thanks, > >>> > >>>> return -EINVAL; > >>>> } > >>>> > >>>> crc = cur_cp_crc(*cp_block); > >>>> if (!f2fs_crc_valid(sbi, crc, *cp_block, crc_offset)) { > >>>> - f2fs_msg(sbi->sb, KERN_WARNING, "invalid crc value"); > >>>> + f2fs_msg(sbi->sb, KERN_WARNING, > >>>> + "invalid crc value at blk_addr: 0x%x", cp_addr); > >>>> + f2fs_bug_on(sbi, 1); > >>>> return -EINVAL; > >>>> } > >>>> > >>>> -- > >>>> 2.10.1 > >>> > >>> . > >>> > > > > . > > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel