On Wed, Jun 13, 2018 at 11:21:30AM +0200, Miklos Szeredi wrote: > On Tue, Jun 12, 2018 at 8:31 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > On Tue, Jun 12, 2018 at 07:24:23PM +0100, Al Viro wrote: > > >> I hate it, but... consider path_open() objections withdrawn for now. > > Is that an ACK for the pull if I follow up with fixes for mmap botch, etc? Yes. > >> Uses of ->vm_file (and rules for those) are too convoluted to untangle > >> at the moment. I still would love to get that straightened out, but > >> it's not this cycle fodder, more's the pity... > > Looked at some other options... What coda mmap does looks very > dubious. It only sets f_mapping, not vm_file. That's going to get > into all sorts of trouble when underlying fs tries to look at > file_inode() or worse, ->private_data. Looks like that should be > converted to what overlayfs does, to have a remote chance of actually > not crashing on most filesystems. Does anybody actually use coda > still? Keep in mind that coda is using the local fs only as cache; IOW, its needs are much more limited than those of overlayfs - local r/w filesystem, disk-backed or tmpfs, used pretty much as a scratch space. > > PS: conversion of ->f_path.dentry is easy and that can probably go this > > cycle - it's a fairly trivial change, with no functional changes unless > > overlayfs is used with <filesystem>, fixing really bad shit if it ever > > gets used thus. I'm not asking to put that into overlayfs pull *and* > > it's independent from the "want to kill that fucking kludge" stuff. > > The latter is too hard for this cycle, unfortunately. > > So this is about adding a file_dentry_check() (or whatever we want to > call it) helper to be used by all filesystems when dereferecing > f_path.dentry, right? file_dentry(), and some of the users should be converted to file_inode(). There's also a missing helper for debugfs uses - more or less a combination of file_dentry() and debugfs_file_get() (if not a conversion of debugfs_file_get() to taking struct file - almost all users are of that form, if not entirely all of them). I've some of that done in local branch... -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
