commit ece95912db94d98e202cbedb8f35206deb29d83d
Author: Jan Kara <jack@suse.cz>
Date:   Wed Feb 6 01:37:13 2008 -0800

    inotify: send IN_ATTRIB events when link count changes
    
    Currently, no notification event has been sent when inode's link count
    changed.  This is inconvenient for the application in some cases:
    
    Suppose you have the following directory structure
    
        foo/test
        bar/
    
    and you watch test.  If someone does "mv foo/test bar/", you get event
    IN_MOVE_SELF and you know something has happened with the file "test".
    However if someone does "ln foo/test bar/test" and "rm foo/test" you get no
    inotify event for the file "test" (only directories "foo" and "bar" receive
    events).
    
    Furthermore it could be argued that link count belongs to file's metadata and
    thus IN_ATTRIB should be sent when it changes.
    
    The following patch implements sending of IN_ATTRIB inotify events when link
    count of the inode changes, i.e., when a hardlink to the inode is created or
    when it is removed.  This event is sent in addition to all the events sent so
    far.  In particular, when a last link to a file is removed, IN_ATTRIB event is
    sent in addition to IN_DELETE_SELF event.
    
    Signed-off-by: Jan Kara <jack@suse.cz>
    Acked-by: Morten Welinder <mwelinder@gmail.com>
    Cc: Robert Love <rlove@google.com>
    Cc: John McCutchan <ttb@tentacle.dhs.org>
    Cc: Steven French <sfrench@us.ibm.com>
    Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/namei.c b/fs/namei.c
index 73e2e66..241cff4 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2188,6 +2188,7 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry)
 
 	/* We don't d_delete() NFS sillyrenamed files--they still exist. */
 	if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) {
+		fsnotify_link_count(dentry->d_inode);
 		d_delete(dentry);
 	}
 
@@ -2360,7 +2361,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
 	error = dir->i_op->link(old_dentry, dir, new_dentry);
 	mutex_unlock(&old_dentry->d_inode->i_mutex);
 	if (!error)
-		fsnotify_create(dir, new_dentry);
+		fsnotify_link(dir, old_dentry->d_inode, new_dentry);
 	return error;
 }
 
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 2bd31fa..d4b7c4a 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -92,6 +92,14 @@ static inline void fsnotify_inoderemove(struct inode *inode)
 }
 
 /*
+ * fsnotify_link_count - inode's link count changed
+ */
+static inline void fsnotify_link_count(struct inode *inode)
+{
+	inotify_inode_queue_event(inode, IN_ATTRIB, 0, NULL, NULL);
+}
+
+/*
  * fsnotify_create - 'name' was linked in
  */
 static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
@@ -103,6 +111,20 @@ static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
 }
 
 /*
+ * fsnotify_link - new hardlink in 'inode' directory
+ * Note: We have to pass also the linked inode ptr as some filesystems leave
+ *   new_dentry->d_inode NULL and instantiate inode pointer later
+ */
+static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct dentry *new_dentry)
+{
+	inode_dir_notify(dir, DN_CREATE);
+	inotify_inode_queue_event(dir, IN_CREATE, 0, new_dentry->d_name.name,
+				  inode);
+	fsnotify_link_count(inode);
+	audit_inode_child(new_dentry->d_name.name, new_dentry, dir);
+}
+
+/*
  * fsnotify_mkdir - directory 'name' was created
  */
 static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)