Unverified Commit 711f9b8f authored by Amir Goldstein's avatar Amir Goldstein Committed by Christian Brauner
Browse files

fsnotify: disable pre-content and permission events by default 



After introducing pre-content events, we had a regression related to
disabling huge faults on files that should never have pre-content events
enabled.

This happened because the default f_mode of allocated files (0) does
not disable pre-content events.

Pre-content events are disabled in file_set_fsnotify_mode_by_watchers()
but internal files may not get to call this helper.

Initialize f_mode to disable permission and pre-content events for all
files and if needed they will be enabled for the callers of
file_set_fsnotify_mode_by_watchers().

Fixes: 20bf82a8 ("mm: don't allow huge faults for files with pre content watches")
Reported-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Closes: https://lore.kernel.org/linux-fsdevel/20250131121703.1e4d00a7.alex.williamson@redhat.com/


Tested-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20250203223205.861346-4-amir73il@gmail.com


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 2a42754b

fs/file_table.c

+5 −0
Original line number Diff line number Diff line
@@ -194,6 +194,11 @@ static int init_file(struct file *f, int flags, const struct cred *cred) 
	 * refcount bumps we should reinitialize the reused file first.

	 */

	file_ref_init(&f->f_ref, 1);

	/*

	 * Disable permission and pre-content events for all files by default.

	 * They may be enabled later by file_set_fsnotify_mode_from_watchers().

	 */

	file_set_fsnotify_mode(f, FMODE_NONOTIFY_PERM);

	return 0;

}