Re: [RFC PATCH] fs: introduce mkdirat2 syscall for atomic mkdir

On Sat Feb 27, 2021 at 11:03 PM EST, Matthew Wilcox wrote:

quoted

1. Program A creates a directory
2. Program A is pre-empted
3. Program B deletes the directory
4. Program A creates a file in that directory
5. RIP

umm ... program B deletes the directory. program A opens it in order to
use openat(). program A gets ENOENT and exits, confused. that's the
race you're removing here -- and it seems fairly insignificant to me.

Yes, that is the race being eliminated here. Instead of this, program A
has an fd which holds a reference to the directory, so it just works. A
race is a race. It's an oversight in the API.