dnotify: reimplement dnotify using fsnotify

Reimplement dnotify using fsnotify.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

MAINTAINERS

@@ -1802,10 +1802,10 @@ F:	drivers/char/epca*
 F:	drivers/char/digi*
 
 DIRECTORY NOTIFICATION (DNOTIFY)
-P:	Stephen Rothwell
-M:	sfr@canb.auug.org.au
+P:	Eric Paris
+M:	eparis@parisplace.org
 L:	linux-kernel@vger.kernel.org
-S:	Supported
+S:	Maintained
 F:	Documentation/filesystems/dnotify.txt
 F:	fs/notify/dnotify/
 F:	include/linux/dnotify.h

fs/notify/dnotify/Kconfig

 config DNOTIFY
 	bool "Dnotify support"
+	depends on FSNOTIFY
 	default y
 	help
 	  Dnotify is a directory-based per-fd file change notification system

include/linux/dnotify.h

@@ -10,7 +10,7 @@
 
 struct dnotify_struct {
 	struct dnotify_struct *	dn_next;
-	unsigned long		dn_mask;
+	__u32			dn_mask;
 	int			dn_fd;
 	struct file *		dn_filp;
 	fl_owner_t		dn_owner;
@@ -21,23 +21,18 @@ struct dnotify_struct {
 
 #ifdef CONFIG_DNOTIFY
 
-extern void __inode_dir_notify(struct inode *, unsigned long);
+#define DNOTIFY_ALL_EVENTS (FS_DELETE | FS_DELETE_CHILD |\
+			    FS_MODIFY | FS_MODIFY_CHILD |\
+			    FS_ACCESS | FS_ACCESS_CHILD |\
+			    FS_ATTRIB | FS_ATTRIB_CHILD |\
+			    FS_CREATE | FS_DN_RENAME |\
+			    FS_MOVED_FROM | FS_MOVED_TO)
+
 extern void dnotify_flush(struct file *, fl_owner_t);
 extern int fcntl_dirnotify(int, struct file *, unsigned long);
-extern void dnotify_parent(struct dentry *, unsigned long);
-
-static inline void inode_dir_notify(struct inode *inode, unsigned long event)
-{
-	if (inode->i_dnotify_mask & (event))
-		__inode_dir_notify(inode, event);
-}
 
 #else
 
-static inline void __inode_dir_notify(struct inode *inode, unsigned long event)
-{
-}
-
 static inline void dnotify_flush(struct file *filp, fl_owner_t id)
 {
 }
@@ -47,14 +42,6 @@ static inline int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
 	return -EINVAL;
 }
 
-static inline void dnotify_parent(struct dentry *dentry, unsigned long event)
-{
-}
-
-static inline void inode_dir_notify(struct inode *inode, unsigned long event)
-{
-}
-
 #endif /* CONFIG_DNOTIFY */
 
 #endif /* __KERNEL __ */

include/linux/fs.h

@@ -760,11 +760,6 @@ struct inode {
 	struct hlist_head	i_fsnotify_mark_entries; /* fsnotify mark entries */
 #endif
 
-#ifdef CONFIG_DNOTIFY
-	unsigned long		i_dnotify_mask; /* Directory notify events */
-	struct dnotify_struct	*i_dnotify; /* for directory notifications */
-#endif
-
 #ifdef CONFIG_INOTIFY
 	struct list_head	inotify_watches; /* watches on this inode */
 	struct mutex		inotify_mutex;	/* protects the watches list */

include/linux/fsnotify.h

@@ -74,13 +74,7 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
 	__u32 new_dir_mask = 0;
 
 	if (old_dir == new_dir) {
-		inode_dir_notify(old_dir, DN_RENAME);
 		old_dir_mask = FS_DN_RENAME;
-	} else {
-		inode_dir_notify(old_dir, DN_DELETE);
-		old_dir_mask = FS_DELETE;
-		inode_dir_notify(new_dir, DN_CREATE);
-		new_dir_mask = FS_CREATE;
 	}
 
 	if (isdir) {
@@ -132,7 +126,6 @@ static inline void fsnotify_nameremove(struct dentry *dentry, int isdir)
 
 	if (isdir)
 		mask |= FS_IN_ISDIR;
-	dnotify_parent(dentry, DN_DELETE);
 
 	fsnotify_parent(dentry, mask);
 }
@@ -154,7 +147,6 @@ static inline void fsnotify_inoderemove(struct inode *inode)
  */
 static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
 {
-	inode_dir_notify(inode, DN_CREATE);
 	inotify_inode_queue_event(inode, IN_CREATE, 0, dentry->d_name.name,
 				  dentry->d_inode);
 	audit_inode_child(dentry->d_name.name, dentry, inode);
@@ -169,7 +161,6 @@ static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
  */
 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);
@@ -186,7 +177,6 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 	__u32 mask = (FS_CREATE | FS_IN_ISDIR);
 	struct inode *d_inode = dentry->d_inode;
 
-	inode_dir_notify(inode, DN_CREATE);
 	inotify_inode_queue_event(inode, mask, 0, dentry->d_name.name, d_inode);
 	audit_inode_child(dentry->d_name.name, dentry, inode);
 
@@ -204,7 +194,6 @@ static inline void fsnotify_access(struct dentry *dentry)
 	if (S_ISDIR(inode->i_mode))
 		mask |= FS_IN_ISDIR;
 
-	dnotify_parent(dentry, DN_ACCESS);
 	inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
 
 	fsnotify_parent(dentry, mask);
@@ -222,7 +211,6 @@ static inline void fsnotify_modify(struct dentry *dentry)
 	if (S_ISDIR(inode->i_mode))
 		mask |= FS_IN_ISDIR;
 
-	dnotify_parent(dentry, DN_MODIFY);
 	inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
 
 	fsnotify_parent(dentry, mask);
@@ -289,47 +277,33 @@ static inline void fsnotify_xattr(struct dentry *dentry)
 static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
 {
 	struct inode *inode = dentry->d_inode;
-	int dn_mask = 0;
-	__u32 in_mask = 0;
+	__u32 mask = 0;
+
+	if (ia_valid & ATTR_UID)
+		mask |= FS_ATTRIB;
+	if (ia_valid & ATTR_GID)
+		mask |= FS_ATTRIB;
+	if (ia_valid & ATTR_SIZE)
+		mask |= FS_MODIFY;
 
-	if (ia_valid & ATTR_UID) {
-		in_mask |= FS_ATTRIB;
-		dn_mask |= DN_ATTRIB;
-	}
-	if (ia_valid & ATTR_GID) {
-		in_mask |= FS_ATTRIB;
-		dn_mask |= DN_ATTRIB;
-	}
-	if (ia_valid & ATTR_SIZE) {
-		in_mask |= FS_MODIFY;
-		dn_mask |= DN_MODIFY;
-	}
 	/* both times implies a utime(s) call */
 	if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
-	{
-		in_mask |= FS_ATTRIB;
-		dn_mask |= DN_ATTRIB;
-	} else if (ia_valid & ATTR_ATIME) {
-		in_mask |= FS_ACCESS;
-		dn_mask |= DN_ACCESS;
-	} else if (ia_valid & ATTR_MTIME) {
-		in_mask |= FS_MODIFY;
-		dn_mask |= DN_MODIFY;
-	}
-	if (ia_valid & ATTR_MODE) {
-		in_mask |= FS_ATTRIB;
-		dn_mask |= DN_ATTRIB;
-	}
+		mask |= FS_ATTRIB;
+	else if (ia_valid & ATTR_ATIME)
+		mask |= FS_ACCESS;
+	else if (ia_valid & ATTR_MTIME)
+		mask |= FS_MODIFY;
 
-	if (dn_mask)
-		dnotify_parent(dentry, dn_mask);
-	if (in_mask) {
+	if (ia_valid & ATTR_MODE)
+		mask |= FS_ATTRIB;
+
+	if (mask) {
 		if (S_ISDIR(inode->i_mode))
-			in_mask |= FS_IN_ISDIR;
-		inotify_inode_queue_event(inode, in_mask, 0, NULL, NULL);
+			mask |= FS_IN_ISDIR;
+		inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
 
-		fsnotify_parent(dentry, in_mask);
-		fsnotify(inode, in_mask, inode, FSNOTIFY_EVENT_INODE);
+		fsnotify_parent(dentry, mask);
+		fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE);
 	}
 }
 

include/linux/fsnotify_backend.h

@@ -57,6 +57,9 @@
 				   FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\
 				   FS_DELETE)
 
+/* listeners that hard code group numbers near the top */
+#define DNOTIFY_GROUP_NUM	UINT_MAX
+
 struct fsnotify_group;
 struct fsnotify_event;
 struct fsnotify_mark_entry;