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. > > Thanks, > > > > >> > >> Thanks, > >> > >>> > >>> Signed-off-by: Jaegeuk Kim <[email protected]> > >>> --- > >>> 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 > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > >
