Hi,

In short:
e2fsck is unable to repair the file system with above error message.

The details:
After todays boot e2fsck aborted with the above error message. I then
ran:

# e2fsck -y    /dev/sdb1
e2fsck 1.42.13 (17-May-2015)
scratch: recovering journal
Superblock needs_recovery flag is clear, but journal has data.
Run journal anyway? yes

e2fsck: unable to set superblock flags on scratch

and also with a backup superblock:

# e2fsck -f  -y  -b 4096000  /dev/sdb1
e2fsck 1.42.13 (17-May-2015)
Superblock needs_recovery flag is clear, but journal has data.
Recovery flag not set in backup superblock, so running journal anyway.
scratch: recovering journal
Superblock needs_recovery flag is clear, but journal has data.
Recovery flag not set in backup superblock, so running journal anyway.
Superblock needs_recovery flag is clear, but journal has data.
Recovery flag not set in backup superblock, so running journal anyway.
e2fsck: unable to set superblock flags on scratch


scratch: ***** FILE SYSTEM WAS MODIFIED *****

scratch: ********** WARNING: Filesystem still has errors **********

So no filesystem check is being run. Afterwards I can mount the
filesystem but when doing some operations I see:

  [43462.717467] EXT4-fs error (device sdb1): __ext4_new_inode:1015: comm http: failed to insert inode 3407: doubly allocated?

so I can't bring the filesystem back into a consistent state.

Cheers,
 -- Guido