Saving error information during journal replay, as in the kernel,prevents information loss from making problems difficult to locate.We save these error information until someone uses e2fsck to checkfor and fix possible errors.

If the file system is mounted, the superblock can be changing whileresize2fs is trying to read the superblock, resulting in checksumfailures. One way of avoiding this problem is read the superblockusing Direct I/O, since the kernel makes sure that what gets writtento disk is self-consistent.
Suggested-by: Krister JohansenSigned-off-by: Theodore Ts'o