2 files changed, 257 insertions, 35 deletions

diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 00fbd5b245c9..6c9ebefdac8e 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -13,6 +13,7 @@
 
 #include <linux/dnotify.h>
 #include <linux/inotify.h>
+#include <linux/fsnotify_backend.h>
 #include <linux/audit.h>
 
 /*
@@ -35,6 +36,16 @@ static inline void fsnotify_d_move(struct dentry *entry)
 }
 
 /*
+ * 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(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE);
+}
+
+/*
  * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
  */
 static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
@@ -43,28 +54,47 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
 {
         struct inode *source = moved->d_inode;
         u32 cookie = inotify_get_cookie();
+        __u32 old_dir_mask = 0;
+        __u32 new_dir_mask = 0;
 
-        if (old_dir == new_dir)
+        if (old_dir == new_dir) {
                 inode_dir_notify(old_dir, DN_RENAME);
-        else {
+                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)
+        if (isdir) {
                 isdir = IN_ISDIR;
+                old_dir_mask |= FS_IN_ISDIR;
+                new_dir_mask |= FS_IN_ISDIR;
+        }
+
+        old_dir_mask |= FS_MOVED_FROM;
+        new_dir_mask |= FS_MOVED_TO;
+
         inotify_inode_queue_event(old_dir, IN_MOVED_FROM|isdir,cookie,old_name,
                                   source);
         inotify_inode_queue_event(new_dir, IN_MOVED_TO|isdir, cookie, new_name,
                                   source);
 
+        fsnotify(old_dir, old_dir_mask, old_dir, FSNOTIFY_EVENT_INODE);
+        fsnotify(new_dir, new_dir_mask, new_dir, FSNOTIFY_EVENT_INODE);
+
         if (target) {
                 inotify_inode_queue_event(target, IN_DELETE_SELF, 0, NULL, NULL);
                 inotify_inode_is_dead(target);
+
+                /* this is really a link_count change not a removal */
+                fsnotify_link_count(target);
         }
 
         if (source) {
                 inotify_inode_queue_event(source, IN_MOVE_SELF, 0, NULL, NULL);
+                fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE);
         }
         audit_inode_child(new_name, moved, new_dir);
 }
@@ -74,10 +104,12 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
  */
 static inline void fsnotify_nameremove(struct dentry *dentry, int isdir)
 {
+        __u32 mask = FS_DELETE;
+
         if (isdir)
-                isdir = IN_ISDIR;
+                mask |= FS_IN_ISDIR;
         dnotify_parent(dentry, DN_DELETE);
-        inotify_dentry_parent_queue_event(dentry, IN_DELETE|isdir, 0, dentry->d_name.name);
+        inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
 }
 
 /*
@@ -87,14 +119,8 @@ static inline void fsnotify_inoderemove(struct inode *inode)
 {
         inotify_inode_queue_event(inode, IN_DELETE_SELF, 0, NULL, NULL);
         inotify_inode_is_dead(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(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE);
 }
 
 /*
@@ -106,6 +132,8 @@ static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
         inotify_inode_queue_event(inode, IN_CREATE, 0, dentry->d_name.name,
                                   dentry->d_inode);
         audit_inode_child(dentry->d_name.name, dentry, inode);
+
+        fsnotify(inode, FS_CREATE, dentry->d_inode, FSNOTIFY_EVENT_INODE);
 }
 
 /*
@@ -120,6 +148,8 @@ static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct
                                   inode);
         fsnotify_link_count(inode);
         audit_inode_child(new_dentry->d_name.name, new_dentry, dir);
+
+        fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE);
 }
 
 /*
@@ -127,10 +157,14 @@ static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct
  */
 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, IN_CREATE | IN_ISDIR, 0, 
-                                  dentry->d_name.name, dentry->d_inode);
+        inotify_inode_queue_event(inode, mask, 0, dentry->d_name.name, d_inode);
         audit_inode_child(dentry->d_name.name, dentry, inode);
+
+        fsnotify(inode, mask, d_inode, FSNOTIFY_EVENT_INODE);
 }
 
 /*
@@ -139,14 +173,16 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 static inline void fsnotify_access(struct dentry *dentry)
 {
         struct inode *inode = dentry->d_inode;
-        u32 mask = IN_ACCESS;
+        __u32 mask = FS_ACCESS;
 
         if (S_ISDIR(inode->i_mode))
-                mask |= IN_ISDIR;
+                mask |= FS_IN_ISDIR;
 
         dnotify_parent(dentry, DN_ACCESS);
         inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
         inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+        fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE);
 }
 
 /*
@@ -155,14 +191,16 @@ static inline void fsnotify_access(struct dentry *dentry)
 static inline void fsnotify_modify(struct dentry *dentry)
 {
         struct inode *inode = dentry->d_inode;
-        u32 mask = IN_MODIFY;
+        __u32 mask = FS_MODIFY;
 
         if (S_ISDIR(inode->i_mode))
-                mask |= IN_ISDIR;
+                mask |= FS_IN_ISDIR;
 
         dnotify_parent(dentry, DN_MODIFY);
         inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
         inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+        fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE);
 }
 
 /*
@@ -171,13 +209,15 @@ static inline void fsnotify_modify(struct dentry *dentry)
 static inline void fsnotify_open(struct dentry *dentry)
 {
         struct inode *inode = dentry->d_inode;
-        u32 mask = IN_OPEN;
+        __u32 mask = FS_OPEN;
 
         if (S_ISDIR(inode->i_mode))
-                mask |= IN_ISDIR;
+                mask |= FS_IN_ISDIR;
 
         inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
         inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+        fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE);
 }
 
 /*
@@ -189,13 +229,15 @@ static inline void fsnotify_close(struct file *file)
         struct inode *inode = dentry->d_inode;
         const char *name = dentry->d_name.name;
         fmode_t mode = file->f_mode;
-        u32 mask = (mode & FMODE_WRITE) ? IN_CLOSE_WRITE : IN_CLOSE_NOWRITE;
+        __u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
 
         if (S_ISDIR(inode->i_mode))
-                mask |= IN_ISDIR;
+                mask |= FS_IN_ISDIR;
 
         inotify_dentry_parent_queue_event(dentry, mask, 0, name);
         inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+        fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE);
 }
 
 /*
@@ -204,13 +246,15 @@ static inline void fsnotify_close(struct file *file)
 static inline void fsnotify_xattr(struct dentry *dentry)
 {
         struct inode *inode = dentry->d_inode;
-        u32 mask = IN_ATTRIB;
+        __u32 mask = FS_ATTRIB;
 
         if (S_ISDIR(inode->i_mode))
-                mask |= IN_ISDIR;
+                mask |= FS_IN_ISDIR;
 
         inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
         inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+        fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE);
 }
 
 /*
@@ -221,34 +265,34 @@ 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 in_mask = 0;
 
         if (ia_valid & ATTR_UID) {
-                in_mask |= IN_ATTRIB;
+                in_mask |= FS_ATTRIB;
                 dn_mask |= DN_ATTRIB;
         }
         if (ia_valid & ATTR_GID) {
-                in_mask |= IN_ATTRIB;
+                in_mask |= FS_ATTRIB;
                 dn_mask |= DN_ATTRIB;
         }
         if (ia_valid & ATTR_SIZE) {
-                in_mask |= IN_MODIFY;
+                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 |= IN_ATTRIB;
+                in_mask |= FS_ATTRIB;
                 dn_mask |= DN_ATTRIB;
         } else if (ia_valid & ATTR_ATIME) {
-                in_mask |= IN_ACCESS;
+                in_mask |= FS_ACCESS;
                 dn_mask |= DN_ACCESS;
         } else if (ia_valid & ATTR_MTIME) {
-                in_mask |= IN_MODIFY;
+                in_mask |= FS_MODIFY;
                 dn_mask |= DN_MODIFY;
         }
         if (ia_valid & ATTR_MODE) {
-                in_mask |= IN_ATTRIB;
+                in_mask |= FS_ATTRIB;
                 dn_mask |= DN_ATTRIB;
         }
 
@@ -256,14 +300,15 @@ static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
                 dnotify_parent(dentry, dn_mask);
         if (in_mask) {
                 if (S_ISDIR(inode->i_mode))
-                        in_mask |= IN_ISDIR;
+                        in_mask |= FS_IN_ISDIR;
                 inotify_inode_queue_event(inode, in_mask, 0, NULL, NULL);
                 inotify_dentry_parent_queue_event(dentry, in_mask, 0,
                                                   dentry->d_name.name);
+                fsnotify(inode, in_mask, inode, FSNOTIFY_EVENT_INODE);
         }
 }
 
-#ifdef CONFIG_INOTIFY   /* inotify helpers */
+#if defined(CONFIG_INOTIFY) || defined(CONFIG_FSNOTIFY) /* notify helpers */
 
 /*
  * fsnotify_oldname_init - save off the old filename before we change it
@@ -281,7 +326,7 @@ static inline void fsnotify_oldname_free(const char *old_name)
         kfree(old_name);
 }
 
-#else   /* CONFIG_INOTIFY */
+#else   /* CONFIG_INOTIFY || CONFIG_FSNOTIFY */
 
 static inline const char *fsnotify_oldname_init(const char *name)
 {
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
new file mode 100644
index 000000000000..1a55718b38aa
--- /dev/null
+++ b/include/linux/fsnotify_backend.h
@@ -0,0 +1,177 @@
+/*
+ * Filesystem access notification for Linux
+ *
+ *  Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
+ */
+
+#ifndef __LINUX_FSNOTIFY_BACKEND_H
+#define __LINUX_FSNOTIFY_BACKEND_H
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h> /* struct inode */
+#include <linux/list.h>
+#include <linux/path.h> /* struct path */
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#include <asm/atomic.h>
+
+/*
+ * IN_* from inotfy.h lines up EXACTLY with FS_*, this is so we can easily
+ * convert between them.  dnotify only needs conversion at watch creation
+ * so no perf loss there.  fanotify isn't defined yet, so it can use the
+ * wholes if it needs more events.
+ */
+#define FS_ACCESS               0x00000001      /* File was accessed */
+#define FS_MODIFY               0x00000002      /* File was modified */
+#define FS_ATTRIB               0x00000004      /* Metadata changed */
+#define FS_CLOSE_WRITE          0x00000008      /* Writtable file was closed */
+#define FS_CLOSE_NOWRITE        0x00000010      /* Unwrittable file closed */
+#define FS_OPEN                 0x00000020      /* File was opened */
+#define FS_MOVED_FROM           0x00000040      /* File was moved from X */
+#define FS_MOVED_TO             0x00000080      /* File was moved to Y */
+#define FS_CREATE               0x00000100      /* Subfile was created */
+#define FS_DELETE               0x00000200      /* Subfile was deleted */
+#define FS_DELETE_SELF          0x00000400      /* Self was deleted */
+#define FS_MOVE_SELF            0x00000800      /* Self was moved */
+
+#define FS_UNMOUNT              0x00002000      /* inode on umount fs */
+#define FS_Q_OVERFLOW           0x00004000      /* Event queued overflowed */
+#define FS_IN_IGNORED           0x00008000      /* last inotify event here */
+
+#define FS_IN_ISDIR             0x40000000      /* event occurred against dir */
+#define FS_IN_ONESHOT           0x80000000      /* only send event once */
+
+#define FS_DN_RENAME            0x10000000      /* file renamed */
+#define FS_DN_MULTISHOT         0x20000000      /* dnotify multishot */
+
+struct fsnotify_group;
+struct fsnotify_event;
+
+/*
+ * Each group much define these ops.  The fsnotify infrastructure will call
+ * these operations for each relevant group.
+ *
+ * handle_event - main call for a group to handle an fs event
+ * free_group_priv - called when a group refcnt hits 0 to clean up the private union
+ */
+struct fsnotify_ops {
+        int (*handle_event)(struct fsnotify_group *group, struct fsnotify_event *event);
+        void (*free_group_priv)(struct fsnotify_group *group);
+};
+
+/*
+ * A group is a "thing" that wants to receive notification about filesystem
+ * events.  The mask holds the subset of event types this group cares about.
+ * refcnt on a group is up to the implementor and at any moment if it goes 0
+ * everything will be cleaned up.
+ */
+struct fsnotify_group {
+        /*
+         * global list of all groups receiving events from fsnotify.
+         * anchored by fsnotify_groups and protected by either fsnotify_grp_mutex
+         * or fsnotify_grp_srcu depending on write vs read.
+         */
+        struct list_head group_list;
+
+        /*
+         * Defines all of the event types in which this group is interested.
+         * This mask is a bitwise OR of the FS_* events from above.  Each time
+         * this mask changes for a group (if it changes) the correct functions
+         * must be called to update the global structures which indicate global
+         * interest in event types.
+         */
+        __u32 mask;
+
+        /*
+         * How the refcnt is used is up to each group.  When the refcnt hits 0
+         * fsnotify will clean up all of the resources associated with this group.
+         * As an example, the dnotify group will always have a refcnt=1 and that
+         * will never change.  Inotify, on the other hand, has a group per
+         * inotify_init() and the refcnt will hit 0 only when that fd has been
+         * closed.
+         */
+        atomic_t refcnt;                /* things with interest in this group */
+        unsigned int group_num;         /* simply prevents accidental group collision */
+
+        const struct fsnotify_ops *ops; /* how this group handles things */
+
+        /* prevents double list_del of group_list.  protected by global fsnotify_gr_mutex */
+        bool on_group_list;
+
+        /* groups can define private fields here or use the void *private */
+        union {
+                void *private;
+        };
+};
+
+/*
+ * all of the information about the original object we want to now send to
+ * a group.  If you want to carry more info from the accessing task to the
+ * listener this structure is where you need to be adding fields.
+ */
+struct fsnotify_event {
+        spinlock_t lock;        /* protection for the associated event_holder and private_list */
+        /* to_tell may ONLY be dereferenced during handle_event(). */
+        struct inode *to_tell;  /* either the inode the event happened to or its parent */
+        /*
+         * depending on the event type we should have either a path or inode
+         * We hold a reference on path, but NOT on inode.  Since we have the ref on
+         * the path, it may be dereferenced at any point during this object's
+         * lifetime.  That reference is dropped when this object's refcnt hits
+         * 0.  If this event contains an inode instead of a path, the inode may
+         * ONLY be used during handle_event().
+         */
+        union {
+                struct path path;
+                struct inode *inode;
+        };
+/* when calling fsnotify tell it if the data is a path or inode */
+#define FSNOTIFY_EVENT_NONE     0
+#define FSNOTIFY_EVENT_PATH     1
+#define FSNOTIFY_EVENT_INODE    2
+#define FSNOTIFY_EVENT_FILE     3
+        int data_type;          /* which of the above union we have */
+        atomic_t refcnt;        /* how many groups still are using/need to send this event */
+        __u32 mask;             /* the type of access, bitwise OR for FS_* event types */
+};
+
+#ifdef CONFIG_FSNOTIFY
+
+/* called from the vfs helpers */
+
+/* main fsnotify call to send events */
+extern void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is);
+
+
+/* called from fsnotify listeners, such as fanotify or dnotify */
+
+/* must call when a group changes its ->mask */
+extern void fsnotify_recalc_global_mask(void);
+/* get a reference to an existing or create a new group */
+extern struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num,
+                                                    __u32 mask,
+                                                    const struct fsnotify_ops *ops);
+/* drop reference on a group from fsnotify_obtain_group */
+extern void fsnotify_put_group(struct fsnotify_group *group);
+
+/* take a reference to an event */
+extern void fsnotify_get_event(struct fsnotify_event *event);
+extern void fsnotify_put_event(struct fsnotify_event *event);
+/* find private data previously attached to an event */
+extern struct fsnotify_event_private_data *fsnotify_get_priv_from_event(struct fsnotify_group *group,
+                                                                        struct fsnotify_event *event);
+
+/* put here because inotify does some weird stuff when destroying watches */
+extern struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
+                                                    void *data, int data_is);
+#else
+
+static inline void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is)
+{}
+#endif  /* CONFIG_FSNOTIFY */
+
+#endif  /* __KERNEL __ */
+
+#endif  /* __LINUX_FSNOTIFY_BACKEND_H */