fanotify: limit reporting of event with non-decodeable file handles

[linux-2.6-microblaze.git] / fs / notify / fanotify / fanotify_user.c

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index f69c451..62fe0b6 100644 (file)
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1585,16 +1585,25 @@ static int fanotify_test_fsid(struct dentry *dentry, __kernel_fsid_t *fsid)
 }
 
 /* Check if filesystem can encode a unique fid */
-static int fanotify_test_fid(struct dentry *dentry)
+static int fanotify_test_fid(struct dentry *dentry, unsigned int flags)
 {
+       unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
+       const struct export_operations *nop = dentry->d_sb->s_export_op;
+
+       /*
+        * We need to make sure that the filesystem supports encoding of
+        * file handles so user can use name_to_handle_at() to compare fids
+        * reported with events to the file handle of watched objects.
+        */
+       if (!nop)
+               return -EOPNOTSUPP;
+
        /*
-        * We need to make sure that the file system supports at least
-        * encoding a file handle so user can use name_to_handle_at() to
-        * compare fid returned with event to the file handle of watched
-        * objects. However, even the relaxed AT_HANDLE_FID flag requires
-        * at least empty export_operations for ecoding unique file ids.
+        * For sb/mount mark, we also need to make sure that the filesystem
+        * supports decoding file handles, so user has a way to map back the
+        * reported fids to filesystem objects.
         */
-       if (!dentry->d_sb->s_export_op)
+       if (mark_type != FAN_MARK_INODE && !nop->fh_to_dentry)
                return -EOPNOTSUPP;
 
        return 0;
@@ -1812,7 +1821,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
                if (ret)
                        goto path_put_and_out;
 
-               ret = fanotify_test_fid(path.dentry);
+               ret = fanotify_test_fid(path.dentry, flags);
                if (ret)
                        goto path_put_and_out;