Re: [PATCH for testing] cow behaviour for hard links
From: Jörn Engel
Date: Fri Mar 12 2004 - 13:31:26 EST
This is assuming we keep current design.
On Fri, 12 March 2004 18:48:57 +0100, Sytse Wielinga wrote:
>
> I have made some pretty thorough changes to your patch though. You can find
> the patch attached to this email.
> Things I've changed:
>
> - moved break_cow_link from dentry_open in open.c to get_write_access in
> namei.c. Putting it in dentry_open thoroughly breaks things, as it's too late
> to save files from being truncated, for example.
True, good catch.
> - made something from the mess you made of ext2/ext3 inode flags :-P
Good. Both variants of my mess worked, so I left it for the moment.
> - removed inheritance, as it's not useful in any way, not expected and breaks
> linking of files with S_COWLINK set.
Not useful? Without inheritance, I have to manually add the flag for
every file/directory I add. Each time I forget, writes go to both
files and I notice the mess weeks later. Naa, that's where we're now
and why I created the patch in the first place.
What we do need, though, is a new errno. -EMLINK is close, but still
wrong.
> - made a go at supporting reiserfs, but failed... my changes are in the
> patch, could somebody please have a look and tell me what I've missed?
No clue, don't care. :)
> - fcntl_setcow now spins a spinlock
Not the only lock I missed. Good.
Jörn
--
He who knows that enough is enough will always have enough.
-- Lao Tsu
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