In the Linux kernel, the following vulnerability has been resolved:
nfsd: add fh_want_write() for early-verified SETATTR in nfsd_proc_setattr()
The BOTH_TIME_SET branch calls fh_verify() early so setattr_prepare()
can inspect the dentry. This causes nfsd_setattr() to skip
fh_want_write(), so notify_change() runs without a mount write
reference.
Add the missing fh_want_write() call after the early fh_verify().
