Messages in this thread | | | Date | Wed, 28 Aug 2013 00:08:27 +0100 | From | Al Viro <> | Subject | Re: [RFC PATCH] fs: Add user_file_or_path_at and use it for truncate |
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On Tue, Aug 27, 2013 at 12:16:34PM -0700, Andy Lutomirski wrote: > This is an experiment to see if we can get nice semantics for all syscalls > that either follow symlinks or allow AT_EMPTY_PATH without jumping through > enormous hoops. This converts truncate (although you can't tell using > truncate from coreutils, because it actually uses open + ftruncate). > > The basic idea is that there's a new helper function > user_file_or_path_at. It takes an fd and a path and, depending on > flags, the emptiness of the path, and whether path is a magic /proc > symlink (or a symlink to a magic /proc/symlink), it returns either a > struct path or a struct file *.
No.
> + path_get(&nd->path); > + if (nd->flags & LOOKUP_FILE) { > + if (nd->last_symlink_file) > + fput(nd->last_symlink_file); > + nd->last_symlink_file = file;
This is ugly (and costs quite a bit of overhead)
> -static int proc_cwd_link(struct dentry *dentry, struct path *path) > +static int proc_cwd_link(struct dentry *dentry, struct file_or_path *link)
... and this is even more vile. Vetoed, for being too ugly to live.
I think I've a saner approach, not involving anything that ugly; I'll post a writeup later tonight.
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