[PATCH] inotify: fix event loss on hardlinked files

People have run into a problem when they do this:

watch (file1, all_events);
watch (file2, some_events);

if file2 is a hard link to file1, some events will be missed because by
default we replace the mask.  The patch below adds a flag IN_MASK_ADD which
will cause inotify to add to the existing mask if present.

Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/inotify.h b/include/linux/inotify.h
index 93bb3afe646..ee5b239092e 100644
--- a/include/linux/inotify.h
+++ b/include/linux/inotify.h
@@ -47,6 +47,7 @@ struct inotify_event {
 #define IN_MOVE                 (IN_MOVED_FROM | IN_MOVED_TO) /* moves */
 
 /* special flags */
+#define IN_MASK_ADD             0x20000000      /* add to the mask of an already existing watch */
 #define IN_ISDIR                0x40000000      /* event occurred against dir */
 #define IN_ONESHOT              0x80000000      /* only send event once */