From 5dd03f55fd2f21916ce248bb2e68bbfb39d94fe5 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 28 Oct 2010 17:21:57 -0400 Subject: [PATCH] fanotify: allow userspace to override max queue depth fanotify has a defualt max queue depth. This patch allows processes which explicitly request it to have an 'unlimited' queue depth. These processes need to be very careful to make sure they cannot fall far enough behind that they OOM the box. Thus this flag is gated on CAP_SYS_ADMIN. Signed-off-by: Eric Paris --- fs/notify/fanotify/fanotify_user.c | 9 ++++++++- include/linux/fanotify.h | 5 +++-- 2 files changed, 11 insertions(+), 3 deletions(-) diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 04f2fe47b66..43d66d9b2ef 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -691,7 +691,14 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) goto out_put_group; } - group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS; + if (flags & FAN_UNLIMITED_QUEUE) { + fd = -EPERM; + if (!capable(CAP_SYS_ADMIN)) + goto out_put_group; + group->max_events = UINT_MAX; + } else { + group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS; + } fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); if (fd < 0) diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h index ed479b6fef7..e37f559c95e 100644 --- a/include/linux/fanotify.h +++ b/include/linux/fanotify.h @@ -28,12 +28,13 @@ #define FAN_CLASS_NOTIF 0x00000000 #define FAN_CLASS_CONTENT 0x00000004 #define FAN_CLASS_PRE_CONTENT 0x00000008 - #define FAN_ALL_CLASS_BITS (FAN_CLASS_NOTIF | FAN_CLASS_CONTENT | \ FAN_CLASS_PRE_CONTENT) +#define FAN_UNLIMITED_QUEUE 0x00000010 + #define FAN_ALL_INIT_FLAGS (FAN_CLOEXEC | FAN_NONBLOCK | \ - FAN_ALL_CLASS_BITS) + FAN_ALL_CLASS_BITS | FAN_UNLIMITED_QUEUE) /* flags used for fanotify_modify_mark() */ #define FAN_MARK_ADD 0x00000001 -- 2.39.3