[RFC][PATCH 2/4] fsnotify: add empty fsnotify_remove() hook

[Amir Goldstein <amir73il@gmail.com>]

We would like to move fsnotify_nameremove() calls from d_delete()
into a higher layer where the hook makes more sense and so we can
consider every d_delete() call site individually.

Start by creating an empty hook called fsnotify_remove() and place
it in the proper VFS call sites.  After all d_delete() call sites
will be converted to use the new hook, it will replace the old
fsnotify_nameremove() hook in d_delete().

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/libfs.c               |  5 ++++-
 fs/namei.c               |  2 ++
 include/linux/fsnotify.h | 13 +++++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/fs/libfs.c b/fs/libfs.c
index 030e67c52b5f..0dd676fc9272 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -10,6 +10,7 @@
 #include <linux/cred.h>
 #include <linux/mount.h>
 #include <linux/vfs.h>
+#include <linux/fsnotify.h>
 #include <linux/quotaops.h>
 #include <linux/mutex.h>
 #include <linux/namei.h>
@@ -367,8 +368,10 @@ int simple_remove(struct inode *dir, struct dentry *dentry)
 	else
 		ret = simple_unlink(dir, dentry);
 
-	if (!ret)
+	if (!ret) {
+		fsnotify_remove(dir, dentry);
 		d_delete(dentry);
+	}
 	dput(dentry);
 
 	return ret;
diff --git a/fs/namei.c b/fs/namei.c
index 20831c2fbb34..c9eda9cc5d43 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3883,6 +3883,7 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry)
 	dentry->d_inode->i_flags |= S_DEAD;
 	dont_mount(dentry);
 	detach_mounts(dentry);
+	fsnotify_remove(dir, dentry);
 
 out:
 	inode_unlock(dentry->d_inode);
@@ -3999,6 +4000,7 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegate
 			if (!error) {
 				dont_mount(dentry);
 				detach_mounts(dentry);
+				fsnotify_remove(dir, dentry);
 			}
 		}
 	}
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 94972e8eb6d1..455dff82595e 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -151,6 +151,19 @@ static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
 	__fsnotify_vfsmount_delete(mnt);
 }
 
+/*
+ * fsnotify_remove - a filename was removed from a directory
+ *
+ * Caller must make sure that dentry->d_name is stable.
+ */
+static inline void fsnotify_remove(struct inode *dir, struct dentry *dentry)
+{
+	/* Expected to be called before d_delete() */
+	WARN_ON_ONCE(d_is_negative(dentry));
+
+	/* TODO: call fsnotify_dirent() */
+}
+
 /*
  * fsnotify_inoderemove - an inode is going away
  */
-- 
2.17.1