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? 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 >>>>>
