[PATCH v2 03/14] fsnotify: add empty fsnotify_{unlink,rmdir}() hooks

[Amir Goldstein <amir73il@xxxxxxxxx>]

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 empty hook fsnotify_{unlink,rmdir}() and place
them in the proper VFS call sites.  After all d_delete() call sites
will be converted to use the new hook, the new hook will generate the
delete events and fsnotify_nameremove() hook will be removed.

Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
 fs/libfs.c               | 11 ++++++++---
 fs/namei.c               |  2 ++
 include/linux/fsnotify.h | 26 ++++++++++++++++++++++++++
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/fs/libfs.c b/fs/libfs.c
index ca1132f1d5c6..4db61ca8cc94 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>
@@ -367,11 +368,15 @@ int simple_remove(struct inode *dir, struct dentry *dentry)
 	 * protect d_delete() from accessing a freed dentry.
 	 */
 	dget(dentry);
-	if (d_is_dir(dentry))
+	if (d_is_dir(dentry)) {
 		ret = simple_rmdir(dir, dentry);
-	else
+		if (!ret)
+			fsnotify_rmdir(dir, dentry);
+	} else {
 		ret = simple_unlink(dir, dentry);
-
+		if (!ret)
+			fsnotify_unlink(dir, dentry);
+	}
 	if (!ret)
 		d_delete(dentry);
 	dput(dentry);
diff --git a/fs/namei.c b/fs/namei.c
index 20831c2fbb34..209c51a5226c 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_rmdir(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_unlink(dir, dentry);
 			}
 		}
 	}
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 94972e8eb6d1..7f23eddefcd0 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -188,6 +188,19 @@ static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct
 	fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, &new_dentry->d_name, 0);
 }
 
+/*
+ * fsnotify_unlink - 'name' was unlinked
+ *
+ * Caller must make sure that dentry->d_name is stable.
+ */
+static inline void fsnotify_unlink(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_mkdir - directory 'name' was created
  */
@@ -198,6 +211,19 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 	fsnotify_dirent(inode, dentry, FS_CREATE | FS_ISDIR);
 }
 
+/*
+ * fsnotify_rmdir - directory 'name' was removed
+ *
+ * Caller must make sure that dentry->d_name is stable.
+ */
+static inline void fsnotify_rmdir(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_access - file was read
  */
-- 
2.17.1