Hi Yunlong, On 2017/8/2 0:59, Yunlong Song wrote: > Hi Chao, > I think there is no need to test mirror bitmap when original bitmap's check > get passed, it is an instruction waste for "test". By the way, previous patch > uses WARN to skip trigger panic when the memory is flipped, I think it is proper > to not trigger panic in this situation, because it is not code bug at all in > such case. Original idea is trying to use bitmap mirror to detect bitmap corruption caused by memory overflow or bit-transition of cache. So if we encounter inconsistency in between original bitmap and mirror bitmap, there may be memory overflow or cache bit-transition, we need to detect that; another case is that both bitmap is consistent, but we are trying to reuse valid block address or free invalid block address, indeed that is a bug. Below modification can cover above two cases, which make original idea of introducing mirror bitmap check working correctly. Thanks, > On 08/01/2017 23:44, Chao Yu <mailto:chao@xxxxxxxxxx> wrote: > > Hi Yunlong, > > How about checking consistence in between original and mirror bitmap all > the time as below? > > --- > fs/f2fs/segment.c | 41 +++++++++++++++++++++++++++-------------- > 1 file changed, 27 insertions(+), 14 deletions(-) > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index a26c24dae70c..f32a19cf486a 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -1510,6 +1510,7 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, > block_t blkaddr, int del) > struct seg_entry *se; > unsigned int segno, offset; > long int new_vblocks; > + bool exist, mir_exist; > > segno = GET_SEGNO(sbi, blkaddr); > > @@ -1526,17 +1527,23 @@ static void update_sit_entry(struct f2fs_sb_info > *sbi, block_t blkaddr, int del) > > /* Update valid block bitmap */ > if (del > 0) { > - if (f2fs_test_and_set_bit(offset, se->cur_valid_map)) { > + exist = f2fs_test_and_set_bit(offset, se->cur_valid_map); > #ifdef CONFIG_F2FS_CHECK_FS > - if (f2fs_test_and_set_bit(offset, > - se->cur_valid_map_mir)) > - f2fs_bug_on(sbi, 1); > - else > - WARN_ON(1); > -#else > + mir_exist = f2fs_test_and_set_bit(offset, > + se->cur_valid_map_mir); > + if (exist != mir_exist) { > + f2fs_msg(sbi->sb, KERN_ERR, "Inconsistent error " > + "when setting bitmap, blk:%u, old bit:%d", > + blkaddr, exist); > f2fs_bug_on(sbi, 1); > + } > #endif > + if (exist) { > + f2fs_msg(sbi->sb, KERN_ERR, > + "Bitmap was set, blk:%u", blkaddr); > + f2fs_bug_on(sbi, 1); > } > + > if (f2fs_discard_en(sbi) && > !f2fs_test_and_set_bit(offset, se->discard_map)) > sbi->discard_blks--; > @@ -1547,17 +1554,23 @@ static void update_sit_entry(struct f2fs_sb_info > *sbi, block_t blkaddr, int del) > se->ckpt_valid_blocks++; > } > } else { > - if (!f2fs_test_and_clear_bit(offset, se->cur_valid_map)) { > + exist = f2fs_test_and_clear_bit(offset, se->cur_valid_map); > #ifdef CONFIG_F2FS_CHECK_FS > - if (!f2fs_test_and_clear_bit(offset, > - se->cur_valid_map_mir)) > - f2fs_bug_on(sbi, 1); > - else > - WARN_ON(1); > -#else > + mir_exist = f2fs_test_and_clear_bit(offset, > + se->cur_valid_map_mir); > + if (exist != mir_exist) { > + f2fs_msg(sbi->sb, KERN_ERR, "Inconsistent error " > + "when clearing bitmap, blk:%u, old bit:%d", > + blkaddr, exist); > f2fs_bug_on(sbi, 1); > + } > #endif > + if (!exist) { > + f2fs_msg(sbi->sb, KERN_ERR, > + "Bitmap was cleared, blk:%u", blkaddr); > + f2fs_bug_on(sbi, 1); > } > + > if (f2fs_discard_en(sbi) && > f2fs_test_and_clear_bit(offset, se->discard_map)) > sbi->discard_blks++; > -- > 2.13.0.90.g1eb437020 > > On 2017/8/1 15:56, Yunlong Song wrote: > > When cur_valid_map passes the f2fs_test_and_set(,clear)_bit test, > > cur_valid_map_mir update is skipped unlikely, so fix it. > > > > Signed-off-by: Yunlong Song <yunlong.song@xxxxxxxxxx> > > --- > > fs/f2fs/segment.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > > index 151968e..6f7731a 100644 > > --- a/fs/f2fs/segment.c > > +++ b/fs/f2fs/segment.c > > @@ -1535,6 +1535,10 @@ static void update_sit_entry(struct f2fs_sb_info > *sbi, block_t blkaddr, int del) > > f2fs_bug_on(sbi, 1); > > #endif > > } > > +#ifdef CONFIG_F2FS_CHECK_FS > > + else > > + f2fs_set_bit(offset, se->cur_valid_map_mir); > > +#endif > > if (f2fs_discard_en(sbi) && > > !f2fs_test_and_set_bit(offset, se->discard_map)) > > sbi->discard_blks--; > > @@ -1556,6 +1560,10 @@ static void update_sit_entry(struct f2fs_sb_info > *sbi, block_t blkaddr, int del) > > f2fs_bug_on(sbi, 1); > > #endif > > } > > +#ifdef CONFIG_F2FS_CHECK_FS > > + else > > + f2fs_clear_bit(offset, se->cur_valid_map_mir); > > +#endif > > if (f2fs_discard_en(sbi) && > > f2fs_test_and_clear_bit(offset, se->discard_map)) > > sbi->discard_blks++; > > >
