On 07/05, Chao Yu wrote: > On 2017/7/1 22:27, Jaegeuk Kim wrote: > > On 07/01, Chao Yu wrote: > >> On 2017/7/1 15:28, Jaegeuk Kim wrote: > >>> On 06/26, Chao Yu wrote: > >>>> Hi Jaegeuk, > >>>> > >>>> On 2017/6/26 22:54, Jaegeuk Kim wrote: > >>>>> Hi Chao, > >>>>> > >>>>> On 06/26, Chao Yu wrote: > >>>>>> Hi Jaegeuk, > >>>>>> > >>>>>> On 2017/6/25 0:25, Jaegeuk Kim wrote: > >>>>>>> - punch_hole > >>>>>>> - fill_zero > >>>>>>> - f2fs_lock_op > >>>>>>> - get_new_data_page > >>>>>>> - lock_page > >>>>>>> > >>>>>>> - f2fs_write_data_pages > >>>>>>> - lock_page > >>>>>>> - do_write_data_page > >>>>>>> - f2fs_lock_op > >>>>>> > >>>>>> Good catch! > >>>>>> > >>>>>> With this implementation, page writeback can fail due to concurrent checkpoint, > >>>>>> this will make fsync/atomic_commit which trigger synchronous write failed randomly. > >>>>>> > >>>>>> How about unifying the lock order in punch_hole as one in writepages for regular > >>>>>> inode? We can add one more parameter in get_new_data_page to indicate whether > >>>>>> callee needs to lock cp_rwsem. > >>>>> > >>>>> Currently, there would be some places to keep cp_rwsem -> page.lock, which seems > >>>>> not simple to change the lock order with page.lock -> cp_rwsem. IMO, we can retry > >>>>> flushing data in f2fs_sync_file, once it gets -EAGAIN. > >>>>> > >>>>> Any thoughts? > >>>> > >>>> What about adding inode_lock in f2fs_sync_file to exclude other > >>>> foreground operation which have reversed lock order? Atomic_commit is OK > >>>> since it has inode_lock in its path. > >>> > >>> I have concerned about performance regression, if we do that. > >> > >> I think fsync vs write or fsync vs fsync scenarios are unusual, so is > >> there any usecase? > > > > Well, that'd be common to call multiple fsync calls at the same time. > > Like dbench or tiotest? > > Do you have test numbers of dbench/tiotest with inode:lock in fsync? No, do we need? > > Thanks, > > > > >> > >> Thanks, > >> > >>> > >>>> > >>>> Thanks, > >>>> > >>>>> > >>>>>> > >>>>>> Thanks, > >>>>>> > >>>>>>> > >>>>>>> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> > >>>>>>> --- > >>>>>>> fs/f2fs/data.c | 5 +++-- > >>>>>>> 1 file changed, 3 insertions(+), 2 deletions(-) > >>>>>>> > >>>>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > >>>>>>> index 7d3af48d34a9..9141bd19a902 100644 > >>>>>>> --- a/fs/f2fs/data.c > >>>>>>> +++ b/fs/f2fs/data.c > >>>>>>> @@ -1404,8 +1404,9 @@ int do_write_data_page(struct f2fs_io_info *fio) > >>>>>>> } > >>>>>>> } > >>>>>>> > >>>>>>> - if (fio->need_lock == LOCK_REQ) > >>>>>>> - f2fs_lock_op(fio->sbi); > >>>>>>> + /* Deadlock due to between page->lock and f2fs_lock_op */ > >>>>>>> + if (fio->need_lock == LOCK_REQ && !f2fs_trylock_op(fio->sbi)) > >>>>>>> + return -EAGAIN; > >>>>>>> > >>>>>>> err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE); > >>>>>>> if (err) > >>>>>>> > >>>>> > >>>>> ------------------------------------------------------------------------------ > >>>>> 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@xxxxxxxxxxxxxxxxxxxxx > >>>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > >>>>>
