On Thu, Jun 25, 2020 at 11:19 AM Jan Kara <jack@xxxxxxx> wrote:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git fsnotify_for_v5.8-rc3
>
> to get a performance improvement to reduce impact of fsnotify for inodes
> where it isn't used.
Pulled.
I do note that there's some commonality here with commit ef1548adada5
("proc: Use new_inode not new_inode_pseudo") and the discussion there
around "maybe new_inode_pseudo should disable fsnotify instead".
See
https://lore.kernel.org/lkml/CAHk-=wh7nZNf81QPcgpDh-0jzt2sOF3rdUEB0UcZvYFHDiMNkw@xxxxxxxxxxxxxx/
and in particular the comment there:
I do wonder if we should have kept the new_inode_pseudo(),
and instead just make fsnotify say "you can't notify on an inode that
isn't on the superblock list"
which is kind of similar to this alloc_file_pseudo() change..
There it wasn't so much about performance, as about an actual bug
(quoting from that commit):
Recently syzbot reported that unmounting proc when there is an ongoing
inotify watch on the root directory of proc could result in a use
after free when the watch is removed after the unmount of proc
when the watcher exits.
but the fnsotify connection and the "pseudo files/inodes can't be
notified about" is the same.
Comments?
Linus
