Messages in this thread | | | From | David Howells <> | Subject | Re: [PATCH 2/2] afs: Add metadata xattrs | Date | Thu, 06 Jul 2017 17:14:11 +0100 |
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Christoph Hellwig <hch@infradead.org> wrote:
> NAK. Don't overload xattrs with magic behavior just to avoid the need > to do proper syscalls or ioctls.
How? This has to work on non-files, files you can't open and mountpoints. You can't do an ioctl() on a file opened O_PATH:
if (unlikely(f->f_flags & O_PATH)) { f->f_mode = FMODE_PATH; f->f_op = &empty_fops; return 0; }
and you can't specify AT_NO_AUTOMOUNT or AT_NO_FOLLOW to openat(), so ioctl() is of no use here.
Do you advocate introducing a pioctl() call? Linus was dead-set against that as I recall.
I could invent a bunch of AFS-specific syscalls, but I'd rather not do that or I suppose bring my fsinfo() patches up to scratch - but you didn't like those either.
Note that using xattrs for fs info is not without precedent in Linux - cifs, for example.
David
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