On Tue, May 29, 2018 at 04:43:06PM +0200, Miklos Szeredi wrote: > This is needed by overlayfs to be able to copy up a file from a read-only > lower layer to a writable layer when being mapped shared. When copying up, > overlayfs takes VFS locks that would violate locking order when nested > inside mmap_sem. > > Add a new f_op->pre_mmap method, which is called before taking mmap_sem. NAK. We really should not add multiple methods for mmap, and everytime this came up we found a better way to solve the problem instead. Most recent example was the socket zero copy receive code.
