ext4: Fix use after free issues with journalled data

Jan Kara
2020-04-21T08:54:50Z

Hello,

this series of patches fixes possible use-after-free issues resulting from
freed inode being still in writeback list. One partner was able to trigger
this using fsstress on filesystem on pmem device. The first patch fixes
mostly a theoretical issue, the third patch fixes a real issue happening
in the wild and leading to kernel crashing.

Honza