path: root/kernel/audit_tree.c
diff options
authorJan Kara <>2014-01-21 15:48:14 -0800
committerLinus Torvalds <>2014-01-21 16:19:41 -0800
commit7053aee26a3548ebaba046ae2e52396ccf56ac6c (patch)
tree1d21fa9409fede7b908ac08df2984766120448db /kernel/audit_tree.c
parente9fe69045bd648d75d8d8099b8658a4ee005a8e5 (diff)
fsnotify: do not share events between notification groups
Currently fsnotify framework creates one event structure for each notification event and links this event into all interested notification groups. This is done so that we save memory when several notification groups are interested in the event. However the need for event structure shared between inotify & fanotify bloats the event structure so the result is often higher memory consumption. Another problem is that fsnotify framework keeps path references with outstanding events so that fanotify can return open file descriptors with its events. This has the undesirable effect that filesystem cannot be unmounted while there are outstanding events - a regression for inotify compared to a situation before it was converted to fsnotify framework. For fanotify this problem is hard to avoid and users of fanotify should kind of expect this behavior when they ask for file descriptors from notified files. This patch changes fsnotify and its users to create separate event structure for each group. This allows for much simpler code (~400 lines removed by this patch) and also smaller event structures. For example on 64-bit system original struct fsnotify_event consumes 120 bytes, plus additional space for file name, additional 24 bytes for second and each subsequent group linking the event, and additional 32 bytes for each inotify group for private data. After the conversion inotify event consumes 48 bytes plus space for file name which is considerably less memory unless file names are long and there are several groups interested in the events (both of which are uncommon). Fanotify event fits in 56 bytes after the conversion (fanotify doesn't care about file names so its events don't have to have it allocated). A win unless there are four or more fanotify groups interested in the event. The conversion also solves the problem with unmount when only inotify is used as we don't have to grab path references for inotify events. [ fanotify: fix corruption preventing startup] Signed-off-by: Jan Kara <> Reviewed-by: Christoph Hellwig <> Cc: Eric Paris <> Cc: Al Viro <> Signed-off-by: Hugh Dickins <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'kernel/audit_tree.c')
1 files changed, 5 insertions, 3 deletions
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index 43c307dc9453..bcc0b1821227 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -912,9 +912,11 @@ static void evict_chunk(struct audit_chunk *chunk)
static int audit_tree_handle_event(struct fsnotify_group *group,
+ struct inode *to_tell,
struct fsnotify_mark *inode_mark,
- struct fsnotify_mark *vfsmonut_mark,
- struct fsnotify_event *event)
+ struct fsnotify_mark *vfsmount_mark,
+ u32 mask, void *data, int data_type,
+ const unsigned char *file_name)
@@ -945,7 +947,7 @@ static const struct fsnotify_ops audit_tree_ops = {
.handle_event = audit_tree_handle_event,
.should_send_event = audit_tree_send_event,
.free_group_priv = NULL,
- .free_event_priv = NULL,
+ .free_event = NULL,
.freeing_mark = audit_tree_freeing_mark,