tree c7932f522ec05e2fcc83e6b4b460abeb2e75a59e
parent 62d53c4a1dfe347bd87ede46ffad38c9a3870338
author Amir Goldstein <amir73il@gmail.com> 1686828149 +0300
committer Christian Brauner <brauner@kernel.org> 1687191484 +0200
gpgsig -----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZJB/vQAKCRCRxhvAZXjc
 ovWgAPsH1iOLOtG2JWRvGg5YhkapmY8xcjKOHCm0nsSDRrIBvgD9FvEi/cCAy9VB
 2oqvMrhNLTPQNeDfoMQRPXIigj5fhAQ=
 =GsxF
 -----END PGP SIGNATURE-----

ovl: enable fsnotify events on underlying real files

Overlayfs creates the real underlying files with fake f_path, whose
f_inode is on the underlying fs and f_path on overlayfs.

Those real files were open with FMODE_NONOTIFY, because fsnotify code was
not prapared to handle fsnotify hooks on files with fake path correctly
and fanotify would report unexpected event->fd with fake overlayfs path,
when the underlying fs was being watched.

Teach fsnotify to handle events on the real files, and do not set real
files to FMODE_NONOTIFY to allow operations on real file (e.g. open,
access, modify, close) to generate async and permission events.

Because fsnotify does not have notifications on address space
operations, we do not need to worry about ->vm_file not reporting
events to a watched overlayfs when users are accessing a mapped
overlayfs file.

Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Message-Id: <20230615112229.2143178-6-amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>