On 09/09, Chao Yu wrote: > On 2019/9/9 16:01, Jaegeuk Kim wrote: > > On 09/09, Chao Yu wrote: > >> On 2019/9/9 15:30, Jaegeuk Kim wrote: > >>> On 09/09, Chao Yu wrote: > >>>> On 2019/9/9 9:25, Jaegeuk Kim wrote: > >>>>> If committing atomic pages is failed when doing f2fs_do_sync_file(), we > >>>>> can > >>>>> get commited pages but atomic_file being still set like: > >>>>> > >>>>> - inmem: 0, atomic IO: 4 (Max. 10), volatile IO: 0 (Max. > >>>>> 0) > >>>>> > >>>>> If GC selects this block, we can get an infinite loop like this: > >>>>> > >>>>> f2fs_submit_page_bio: dev = (253,7), ino = 2, page_index = 0x2359a8, > >>>>> oldaddr = 0x2359a8, newaddr = 0x2359a8, rw = READ(), type = COLD_DATA > >>>>> f2fs_submit_read_bio: dev = (253,7)/(253,7), rw = READ(), DATA, sector > >>>>> = 18533696, size = 4096 > >>>>> f2fs_get_victim: dev = (253,7), type = No TYPE, policy = (Foreground > >>>>> GC, LFS-mode, Greedy), victim = 4355, cost = 1, ofs_unit = 1, > >>>>> pre_victim_secno = 4355, prefree = 0, free = 234 > >>>>> f2fs_iget: dev = (253,7), ino = 6247, pino = 5845, i_mode = 0x81b0, > >>>>> i_size = 319488, i_nlink = 1, i_blocks = 624, i_advise = 0x2c > >>>>> f2fs_submit_page_bio: dev = (253,7), ino = 2, page_index = 0x2359a8, > >>>>> oldaddr = 0x2359a8, newaddr = 0x2359a8, rw = READ(), type = COLD_DATA > >>>>> f2fs_submit_read_bio: dev = (253,7)/(253,7), rw = READ(), DATA, sector > >>>>> = 18533696, size = 4096 > >>>>> f2fs_get_victim: dev = (253,7), type = No TYPE, policy = (Foreground > >>>>> GC, LFS-mode, Greedy), victim = 4355, cost = 1, ofs_unit = 1, > >>>>> pre_victim_secno = 4355, prefree = 0, free = 234 > >>>>> f2fs_iget: dev = (253,7), ino = 6247, pino = 5845, i_mode = 0x81b0, > >>>>> i_size = 319488, i_nlink = 1, i_blocks = 624, i_advise = 0x2c > >>>>> > >>>>> In that moment, we can observe: > >>>>> > >>>>> [Before] > >>>>> Try to move 5084219 blocks (BG: 384508) > >>>>> - data blocks : 4962373 (274483) > >>>>> - node blocks : 121846 (110025) > >>>>> Skipped : atomic write 4534686 (10) > >>>>> > >>>>> [After] > >>>>> Try to move 5088973 blocks (BG: 384508) > >>>>> - data blocks : 4967127 (274483) > >>>>> - node blocks : 121846 (110025) > >>>>> Skipped : atomic write 4539440 (10) > >>>>> > >>>>> Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org> > >>>>> --- > >>>>> fs/f2fs/file.c | 10 +++++----- > >>>>> 1 file changed, 5 insertions(+), 5 deletions(-) > >>>>> > >>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > >>>>> index 7ae2f3bd8c2f..68b6da734e5f 100644 > >>>>> --- a/fs/f2fs/file.c > >>>>> +++ b/fs/f2fs/file.c > >>>>> @@ -1997,11 +1997,11 @@ static int f2fs_ioc_commit_atomic_write(struct > >>>>> file *filp) > >>>>> goto err_out; > >>>>> > >>>>> ret = f2fs_do_sync_file(filp, 0, LLONG_MAX, 0, true); > >>>>> - if (!ret) { > >>>>> - clear_inode_flag(inode, FI_ATOMIC_FILE); > >>>>> - F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC] > >>>>> = 0; > >>>>> - stat_dec_atomic_write(inode); > >>>>> - } > >>>>> + > >>>>> + /* doesn't need to check error */ > >>>>> + clear_inode_flag(inode, FI_ATOMIC_FILE); > >>>>> + F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC] = 0; > >>>>> + stat_dec_atomic_write(inode); > >>>> > >>>> If there are still valid atomic write pages linked in .inmem_pages, it > >>>> may cause > >>>> memory leak when we just clear FI_ATOMIC_FILE flag. > >>> > >>> f2fs_commit_inmem_pages() should have flushed them. > >> > >> Oh, we failed to flush its nodes. > >> > >> However we won't clear such info if we failed to flush inmen pages, it > >> looks > >> inconsistent. > >> > >> Any interface needed to drop inmem pages or clear ATOMIC_FILE flag in that > >> two > >> error path? I'm not very clear how sqlite handle such error. > > > > f2fs_drop_inmem_pages() did that, but not in this case. > > What I mean is, for any error returned from atomic_commit() interface, should > userspace application handle it with consistent way, like trigger > f2fs_drop_inmem_pages(), so we don't need to handle it inside atomic_commit().
f2fs_ioc_abort_volatile_write() will be triggered. > > > > >> > >> Thanks, > >> > >>> > >>>> > >>>> So my question is why below logic didn't handle such condition well? > >>>> > >>>> f2fs_gc() > >>>> > >>>> if (has_not_enough_free_secs(sbi, sec_freed, 0)) { > >>>> if (skipped_round <= MAX_SKIP_GC_COUNT || > >>>> skipped_round * 2 < round) { > >>>> segno = NULL_SEGNO; > >>>> goto gc_more; > >>>> } > >>>> > >>>> if (first_skipped < last_skipped && > >>>> (last_skipped - first_skipped) > > >>>> sbi->skipped_gc_rwsem) { > >>>> f2fs_drop_inmem_pages_all(sbi, true); > >>> > >>> This is doing nothing, since f2fs_commit_inmem_pages() removed the inode > >>> from inmem list. > >>> > >>>> segno = NULL_SEGNO; > >>>> goto gc_more; > >>>> } > >>>> if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED)) > >>>> ret = f2fs_write_checkpoint(sbi, &cpc); > >>>> } > >>>> > >>>>> } else { > >>>>> ret = f2fs_do_sync_file(filp, 0, LLONG_MAX, 1, false); > >>>>> } > >>>>> > >>> . > >>> > > . > >