1 files changed, 102 insertions, 14 deletions

diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index ea05b8a401e7..68b30504284c 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -2,26 +2,112 @@
 #include <linux/fsnotify_backend.h>
 #include <linux/path.h>
 #include <linux/slab.h>
+#include <linux/exportfs.h>
 
 extern struct kmem_cache *fanotify_mark_cache;
 extern struct kmem_cache *fanotify_event_cachep;
 extern struct kmem_cache *fanotify_perm_event_cachep;
 
+/* Possible states of the permission event */
+enum {
+	FAN_EVENT_INIT,
+	FAN_EVENT_REPORTED,
+	FAN_EVENT_ANSWERED,
+	FAN_EVENT_CANCELED,
+};
+
+/*
+ * 3 dwords are sufficient for most local fs (64bit ino, 32bit generation).
+ * For 32bit arch, fid increases the size of fanotify_event by 12 bytes and
+ * fh_* fields increase the size of fanotify_event by another 4 bytes.
+ * For 64bit arch, fid increases the size of fanotify_fid by 8 bytes and
+ * fh_* fields are packed in a hole after mask.
+ */
+#if BITS_PER_LONG == 32
+#define FANOTIFY_INLINE_FH_LEN	(3 << 2)
+#else
+#define FANOTIFY_INLINE_FH_LEN	(4 << 2)
+#endif
+
+struct fanotify_fid {
+	__kernel_fsid_t fsid;
+	union {
+		unsigned char fh[FANOTIFY_INLINE_FH_LEN];
+		unsigned char *ext_fh;
+	};
+};
+
+static inline void *fanotify_fid_fh(struct fanotify_fid *fid,
+				    unsigned int fh_len)
+{
+	return fh_len <= FANOTIFY_INLINE_FH_LEN ? fid->fh : fid->ext_fh;
+}
+
+static inline bool fanotify_fid_equal(struct fanotify_fid *fid1,
+				      struct fanotify_fid *fid2,
+				      unsigned int fh_len)
+{
+	return fid1->fsid.val[0] == fid2->fsid.val[0] &&
+		fid1->fsid.val[1] == fid2->fsid.val[1] &&
+		!memcmp(fanotify_fid_fh(fid1, fh_len),
+			fanotify_fid_fh(fid2, fh_len), fh_len);
+}
+
 /*
  * Structure for normal fanotify events. It gets allocated in
  * fanotify_handle_event() and freed when the information is retrieved by
  * userspace
  */
-struct fanotify_event_info {
+struct fanotify_event {
 	struct fsnotify_event fse;
+	u32 mask;
 	/*
-	 * We hold ref to this path so it may be dereferenced at any point
-	 * during this object's lifetime
+	 * Those fields are outside fanotify_fid to pack fanotify_event nicely
+	 * on 64bit arch and to use fh_type as an indication of whether path
+	 * or fid are used in the union:
+	 * FILEID_ROOT (0) for path, > 0 for fid, FILEID_INVALID for neither.
 	 */
-	struct path path;
+	u8 fh_type;
+	u8 fh_len;
+	u16 pad;
+	union {
+		/*
+		 * We hold ref to this path so it may be dereferenced at any
+		 * point during this object's lifetime
+		 */
+		struct path path;
+		/*
+		 * With FAN_REPORT_FID, we do not hold any reference on the
+		 * victim object. Instead we store its NFS file handle and its
+		 * filesystem's fsid as a unique identifier.
+		 */
+		struct fanotify_fid fid;
+	};
 	struct pid *pid;
 };
 
+static inline bool fanotify_event_has_path(struct fanotify_event *event)
+{
+	return event->fh_type == FILEID_ROOT;
+}
+
+static inline bool fanotify_event_has_fid(struct fanotify_event *event)
+{
+	return event->fh_type != FILEID_ROOT &&
+		event->fh_type != FILEID_INVALID;
+}
+
+static inline bool fanotify_event_has_ext_fh(struct fanotify_event *event)
+{
+	return fanotify_event_has_fid(event) &&
+		event->fh_len > FANOTIFY_INLINE_FH_LEN;
+}
+
+static inline void *fanotify_event_fh(struct fanotify_event *event)
+{
+	return fanotify_fid_fh(&event->fid, event->fh_len);
+}
+
 /*
  * Structure for permission fanotify events. It gets allocated and freed in
  * fanotify_handle_event() since we wait there for user response. When the
@@ -29,16 +115,17 @@ struct fanotify_event_info {
  * group->notification_list to group->fanotify_data.access_list to wait for
  * user response.
  */
-struct fanotify_perm_event_info {
-	struct fanotify_event_info fae;
-	int response;	/* userspace answer to question */
+struct fanotify_perm_event {
+	struct fanotify_event fae;
+	unsigned short response;	/* userspace answer to the event */
+	unsigned short state;		/* state of the event */
 	int fd;		/* fd we passed to userspace for this event */
 };
 
-static inline struct fanotify_perm_event_info *
+static inline struct fanotify_perm_event *
 FANOTIFY_PE(struct fsnotify_event *fse)
 {
-	return container_of(fse, struct fanotify_perm_event_info, fae.fse);
+	return container_of(fse, struct fanotify_perm_event, fae.fse);
 }
 
 static inline bool fanotify_is_perm_event(u32 mask)
@@ -47,11 +134,12 @@ static inline bool fanotify_is_perm_event(u32 mask)
 		mask & FANOTIFY_PERM_EVENTS;
 }
 
-static inline struct fanotify_event_info *FANOTIFY_E(struct fsnotify_event *fse)
+static inline struct fanotify_event *FANOTIFY_E(struct fsnotify_event *fse)
 {
-	return container_of(fse, struct fanotify_event_info, fse);
+	return container_of(fse, struct fanotify_event, fse);
 }
 
-struct fanotify_event_info *fanotify_alloc_event(struct fsnotify_group *group,
-						 struct inode *inode, u32 mask,
-						 const struct path *path);
+struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
+					    struct inode *inode, u32 mask,
+					    const void *data, int data_type,
+					    __kernel_fsid_t *fsid);