f2fs: avoid hungtask problem caused by losing wake_up

The D state of wait_on_all_pages_writeback should be waken by
function f2fs_write_end_io when all writeback pages have been
succesfully written to device. It's possible that wake_up comes
between get_pages and io_schedule. Maybe in this case it will
lost wake_up and still in D state even if all pages have been
write back to device, and finally, the whole system will be into
the hungtask state.

                if (!get_pages(sbi, F2FS_WRITEBACK))
                         break;
					<---------  wake_up
                io_schedule();

Signed-off-by: Yunlei He <heyunlei@huawei.com>
Signed-off-by: Biao He <hebiao6@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 2bac8a1..f55355d 100644 (file)
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -920,7 +920,7 @@ static void wait_on_all_pages_writeback(struct f2fs_sb_info *sbi)
                if (!get_pages(sbi, F2FS_WRITEBACK))
                        break;
 
-               io_schedule();
+               io_schedule_timeout(5*HZ);
        }
        finish_wait(&sbi->cp_wait, &wait);
 }