On Fri, Oct 15, 2021 at 12:39 AM Gabriel Krisman Bertazi
<krisman@xxxxxxxxxxxxx> wrote:
>
> Since FAN_FS_ERROR memory must be pre-allocated, limit a single group
> from watching too many file systems at once. The current scheme
> guarantees 1 slot per filesystem, so limit the number of marks with
> FAN_FS_ERROR per group.
>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
> ---
> fs/notify/fanotify/fanotify_user.c | 10 ++++++++++
> include/linux/fsnotify_backend.h | 1 +
> 2 files changed, 11 insertions(+)
>
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index f1cf863d6f9f..5324890500fc 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -959,6 +959,10 @@ static int fanotify_remove_mark(struct fsnotify_group *group,
>
> removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags,
> umask, &destroy_mark);
> +
> + if (removed & FAN_FS_ERROR)
> + group->fanotify_data.error_event_marks--;
> +
> if (removed & fsnotify_conn_mask(fsn_mark->connector))
> fsnotify_recalc_mask(fsn_mark->connector);
> if (destroy_mark)
> @@ -1057,6 +1061,9 @@ static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group,
>
> static int fanotify_group_init_error_pool(struct fsnotify_group *group)
> {
> + if (group->fanotify_data.error_event_marks >= FANOTIFY_DEFAULT_FEE_POOL)
> + return -ENOMEM;
Why not try to mempool_resize()?
Also, I did not read the rest of the patches yet, but don't we need two
slots per mark? one for alloc-pre-enqueue and one for free-post-dequeue?
Thanks,
Amir.
