lkml.org 
[lkml]   [2013]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [RFC PATCH] vfs: add permute operation
From
On Tue, May 28, 2013 at 7:36 PM, Zach Brown <zab@redhat.com> wrote:
> Some quick thoughts:
>
>> Permute the location of files. E.g. 'permute(A, B, C)' is equivalent to A->B,
>> B->C and C->A. This is essentially a series of renames done as a single atomic
>> operation.
>
> Hmm. Can we choose a more specific name than 'permute'? To me,
> ->permute() tells me just as much about the operation as
> ->do_something(). {multi,bulk,mass}_rename()? renamev()?

It's not just plain muti-rename, but a cyclic one. Maybe cyclic_rename()?

>> +static void sort_parents3(struct dentry **p)
>> +void sort_parents(struct dentry **p, unsigned *nump)
>
> Yikes, that's a bunch of fiddly code. Is it *really* worth all that to
> avoid calling the generic sort helpers?

AFAICS, I cannot make the compare function transitive, e.g.: A is
descendant of C but B is unrelated. Then what should cmp(A, B) and
cmp(B, C) return?

>
>> + if (WARN_ON(num > PERMUTE_MAX) ||
>> + WARN_ON(num < 2))
>> + return -EINVAL;
>
> And in other places this is a BUG? Why not, like the syscall, limit the
> arguments to three if we're serious about that limitation?

I could be more consistent with the BUGs. Doing it with 3 args is not
necessarily good, since then we can't do loops and the chance of a
copy-paste error is increased.

Thanks,
Miklos


\
 
 \ /
  Last update: 2013-05-29 10:41    [W:0.134 / U:0.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site