Re: [PATCH v3] fs: let backing files inherit FMODE_NONOTIFY from the user file

[Christian Brauner]

On Thu, 29 Oct 2026 22:18:40 +0100, Edvard Conrad wrote:
> When fanotify reports a permission event, copy_event_to_user() creates
> the event fd with dentry_open_nonotify(), so that the listener's use of
> that fd does not generate further events. If the event's path is on a
> stacked filesystem, the stacked filesystem's ->open() opens the real
> file with backing_file_open(). Since commit ebe559609d78 ("fs: get rid
> of __FMODE_NONOTIFY kludge"), FMODE_NONOTIFY lives in f_mode only and
> the backing file does not inherit it: it is allocated with the default
> fsnotify mode, and fsnotify_open_perm_and_set_mode() raises FS_OPEN_PERM
> on the real path if the backing filesystem has permission event
> watchers.
> 
> [...]

Applied to the vfs.fixes branch of the vfs/vfs.git tree.
Patches in the vfs.fixes branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.fixes

[1/1] fs: let backing files inherit FMODE_NONOTIFY from the user file
      https://git.kernel.org/vfs/vfs/c/c3d355f427ce