> I've accidentally mounted one overlayfs over another and got obvious > warning from lockdep: i_mutex lockdep classes are per-fs-type. > > # mount -t overlay overlay 1 -o > upperdir=1_upper,workdir=1_work,lowerdir=1_lower > # mount -t overlay overlay 2 -o upperdir=2_upper,workdir=2_work,lowerdir=1 > # ls 2 This reporting is positive, we are not in deadlock situation actually. The "2" dir of overlayfs will call iterate_dir->"1" dir of overlayfs->iterate_dir, and the nest iterate_dir happened on the same file system, so the warning came out. We'd better make the lower and upper in different fs instance, and this warning will disappear. And this lockdep warning happened when the nest iterate_dir call of same fs(I mean the same super block). The function check_deadlock in lockdep.c will report the nest lock of same process. If we make the 2_upper and 2_work in a different fs, no warning comes out. Thanks, -- George Wang 王旭 Kernel Quantity Engineer Red Hat Software (Beijing) Co.,Ltd IRC:xuw Tel:+86-010-62608041 Phone:15901231579 9/F, Tower C, Raycom -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
