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. 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 >
