Re: [patch 01/10] vfs: add path_create() and path_mknod()

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 6 May 2008 05:24:26 +0100 Al Viro <viro@ZenIV.linux.org.uk> wrote:

> On Mon, May 05, 2008 at 09:12:51PM -0700, Andrew Morton wrote:
> > On Mon, 05 May 2008 12:16:22 +0200 Miklos Szeredi <miklos@szeredi.hu> wrote:
> > 
> > > R/O bind mounts require operations which modify the filesystem to be
> > > wrapped in mnt_want_write()/mnt_drop_write().  Create helpers which do
> > > this, so callers won't need to bother, and more importantly, cannot
> > > forget!  Call these path_*, analogous to vfs_*.  Since there are no
> > > callers of vfs_* left, make them static.
> > 
> > ooh, yum.  This appears to address my main complaint about the r-o-bind-mount
> > stuff: fragility.
> > 
> > > Overall this patchset is just 23 lines in the red, but at the same
> > > time it fixes several places in nfsd and the whole of ecryptfs, where
> > > the mnt_want_write/drop_write() calls were missing.
> > 
> > Yeah, like that.
> 
> Except that it fixes nothing in nfsd, as we'd already figured out and
> "solution" for ecryptfs is more than slightly dubious.  Not that nfsd
> one wasn't...

Well OK.  But those open-coded mnt_want_write() calls all over the place
still stink.