On 05/30, Chao Yu wrote: > On 2020/5/30 6:34, Jaegeuk Kim wrote: > > On 05/29, Chao Yu wrote: > >> Under heavy fsstress, we may triggle panic while issuing discard, > >> because __check_sit_bitmap() detects that discard command may earse > >> valid data blocks, the root cause is as below race stack described, > >> since we removed lock when flushing quota data, quota data writeback > >> may race with write_checkpoint(), so that it causes inconsistency in > >> between cached discard entry and segment bitmap. > >> > >> - f2fs_write_checkpoint > >> - block_operations > >> - set_sbi_flag(sbi, SBI_QUOTA_SKIP_FLUSH) > >> - f2fs_flush_sit_entries > >> - add_discard_addrs > >> - __set_bit_le(i, (void *)de->discard_map); > >> - f2fs_write_data_pages > >> - f2fs_write_single_data_page > >> : inode is quota one, > >> cp_rwsem won't be locked > >> - f2fs_do_write_data_page > >> - f2fs_allocate_data_block > >> - f2fs_wait_discard_bio > >> : discard entry has not > >> been added yet. > >> - update_sit_entry > >> - f2fs_clear_prefree_segments > >> - f2fs_issue_discard > >> : add discard entry > >> > >> This patch fixes this issue by reverting 435cbab95e39 ("f2fs: fix > >> quota_sync > >> failure due to f2fs_lock_op"). > >> > >> Fixes: 435cbab95e39 ("f2fs: fix quota_sync failure due to f2fs_lock_op") > > > > The previous patch fixes quota_sync gets EAGAIN all the time. > > How about this? It seems this works for fsstress test. > >
Then this? --- fs/f2fs/segment.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index ebbadde6cbced..ed11dcf2d69ed 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -3107,6 +3107,14 @@ void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page, type = CURSEG_COLD_DATA; } + /* + * We need to wait for node_write to avoid block allocation during + * checkpoint. This can only happen to quota writes which can cause + * the below discard race condition. + */ + if (IS_DATASEG(type)) + down_write(&sbi->node_write); + down_read(&SM_I(sbi)->curseg_lock); mutex_lock(&curseg->curseg_mutex); @@ -3174,6 +3182,9 @@ void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page, if (put_pin_sem) up_read(&sbi->pin_sem); + + if (IS_DATASEG(type)) + up_write(&sbi->node_write); } static void update_device_state(struct f2fs_io_info *fio) -- 2.27.0.rc0.183.gde8f92d652-goog