Re: New copyfile system call - discuss before LSF?

Myklebust, Trond
2013-03-30T21:57:10Z

On Mar 30, 2013, at 5:45 PM, Pavel Machek <pavel@ucw.cz>
wrote:

> On Sat 2013-03-30 13:08:39, Andreas Dilger wrote:
>> On 2013-03-30, at 12:49 PM, Pavel Machek wrote:
>>> Hmm, really? AFAICT it would be simple to provide an
>>> open_deleted_file("directory") syscall. You'd open_deleted_file(),
>>> copy source file into it, then fsync(), then link it into filesystem.
>>>
>>> That should have atomicity properties reflected.
>>
>> Actually, the open_deleted_file() syscall is quite useful for many
>> different things all by itself. Lots of applications need to create
>> temporary files that are unlinked at application failure (without a
>> race if app crashes after creating the file, but before unlinking).
>> It also avoids exposing temporary files into the namespace if other
>> applications are accessing the directory.
>
> Hmm. open_deleted_file() will still need to get a directory... so it
> will still need a path. Perhaps open("/foo/bar/mnt", O_DELETED) would
> be acceptable interface?
> Pavel

...and what's the big plan to make this work on anything other than ext4 and btrfs?

Cheers,
Trond