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authorEric Paris <eparis@redhat.com>2010-10-28 17:21:57 -0400
committerEric Paris <eparis@redhat.com>2010-10-28 17:22:14 -0400
commit5dd03f55fd2f21916ce248bb2e68bbfb39d94fe5 (patch)
tree3d4446ce07126b9983849a41670542c69bb400bd
parent2529a0df0f64dab1f60ae08e038b89c53a6b4c02 (diff)
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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 <eparis@redhat.com>
-rw-r--r--fs/notify/fanotify/fanotify_user.c9
-rw-r--r--include/linux/fanotify.h5
2 files changed, 11 insertions, 3 deletions
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 04f2fe4..43d66d9 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 ed479b6..e37f559 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