1 files changed, 65 insertions, 11 deletions

diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 6918b98faeb6..01620ebae1bd 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -606,6 +606,7 @@ static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
 {
 	int res;
 	struct dentry *dentry = path->dentry;
+	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
 	struct ovl_dir_cache *cache;
 
 	cache = ovl_dir_cache(d_inode(dentry));
@@ -632,7 +633,7 @@ static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
 		 * Removing the "impure" xattr is best effort.
 		 */
 		if (!ovl_want_write(dentry)) {
-			ovl_do_removexattr(ovl_dentry_upper(dentry),
+			ovl_do_removexattr(ofs, ovl_dentry_upper(dentry),
 					   OVL_XATTR_IMPURE);
 			ovl_drop_write(dentry);
 		}
@@ -839,7 +840,7 @@ out_unlock:
 	return res;
 }
 
-static struct file *ovl_dir_open_realfile(struct file *file,
+static struct file *ovl_dir_open_realfile(const struct file *file,
 					  struct path *realpath)
 {
 	struct file *res;
@@ -852,16 +853,22 @@ static struct file *ovl_dir_open_realfile(struct file *file,
 	return res;
 }
 
-static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
-			 int datasync)
+/*
+ * Like ovl_real_fdget(), returns upperfile if dir was copied up since open.
+ * Unlike ovl_real_fdget(), this caches upperfile in file->private_data.
+ *
+ * TODO: use same abstract type for file->private_data of dir and file so
+ * upperfile could also be cached for files as well.
+ */
+struct file *ovl_dir_real_file(const struct file *file, bool want_upper)
 {
+
 	struct ovl_dir_file *od = file->private_data;
 	struct dentry *dentry = file->f_path.dentry;
 	struct file *realfile = od->realfile;
 
-	/* Nothing to sync for lower */
 	if (!OVL_TYPE_UPPER(ovl_path_type(dentry)))
-		return 0;
+		return want_upper ? NULL : realfile;
 
 	/*
 	 * Need to check if we started out being a lower dir, but got copied up
@@ -880,7 +887,7 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
 			if (!od->upperfile) {
 				if (IS_ERR(realfile)) {
 					inode_unlock(inode);
-					return PTR_ERR(realfile);
+					return realfile;
 				}
 				smp_store_release(&od->upperfile, realfile);
 			} else {
@@ -893,6 +900,25 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
 		}
 	}
 
+	return realfile;
+}
+
+static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
+			 int datasync)
+{
+	struct file *realfile;
+	int err;
+
+	if (!ovl_should_sync(OVL_FS(file->f_path.dentry->d_sb)))
+		return 0;
+
+	realfile = ovl_dir_real_file(file, true);
+	err = PTR_ERR_OR_ZERO(realfile);
+
+	/* Nothing to sync for lower */
+	if (!realfile || err)
+		return err;
+
 	return vfs_fsync_range(realfile, start, end, datasync);
 }
 
@@ -945,6 +971,10 @@ const struct file_operations ovl_dir_operations = {
 	.llseek		= ovl_dir_llseek,
 	.fsync		= ovl_dir_fsync,
 	.release	= ovl_dir_release,
+	.unlocked_ioctl	= ovl_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ovl_compat_ioctl,
+#endif
 };
 
 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list)
@@ -1051,7 +1081,9 @@ int ovl_check_d_type_supported(struct path *realpath)
 	return rdd.d_type_supported;
 }
 
-static void ovl_workdir_cleanup_recurse(struct path *path, int level)
+#define OVL_INCOMPATDIR_NAME "incompat"
+
+static int ovl_workdir_cleanup_recurse(struct path *path, int level)
 {
 	int err;
 	struct inode *dir = path->dentry->d_inode;
@@ -1065,6 +1097,19 @@ static void ovl_workdir_cleanup_recurse(struct path *path, int level)
 		.root = &root,
 		.is_lowest = false,
 	};
+	bool incompat = false;
+
+	/*
+	 * The "work/incompat" directory is treated specially - if it is not
+	 * empty, instead of printing a generic error and mounting read-only,
+	 * we will error about incompat features and fail the mount.
+	 *
+	 * When called from ovl_indexdir_cleanup(), path->dentry->d_name.name
+	 * starts with '#'.
+	 */
+	if (level == 2 &&
+	    !strcmp(path->dentry->d_name.name, OVL_INCOMPATDIR_NAME))
+		incompat = true;
 
 	err = ovl_dir_read(path, &rdd);
 	if (err)
@@ -1079,17 +1124,25 @@ static void ovl_workdir_cleanup_recurse(struct path *path, int level)
 				continue;
 			if (p->len == 2 && p->name[1] == '.')
 				continue;
+		} else if (incompat) {
+			pr_err("overlay with incompat feature '%s' cannot be mounted\n",
+				p->name);
+			err = -EINVAL;
+			break;
 		}
 		dentry = lookup_one_len(p->name, path->dentry, p->len);
 		if (IS_ERR(dentry))
 			continue;
 		if (dentry->d_inode)
-			ovl_workdir_cleanup(dir, path->mnt, dentry, level);
+			err = ovl_workdir_cleanup(dir, path->mnt, dentry, level);
 		dput(dentry);
+		if (err)
+			break;
 	}
 	inode_unlock(dir);
 out:
 	ovl_cache_free(&list);
+	return err;
 }
 
 int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
@@ -1106,9 +1159,10 @@ int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
 		struct path path = { .mnt = mnt, .dentry = dentry };
 
 		inode_unlock(dir);
-		ovl_workdir_cleanup_recurse(&path, level + 1);
+		err = ovl_workdir_cleanup_recurse(&path, level + 1);
 		inode_lock_nested(dir, I_MUTEX_PARENT);
-		err = ovl_cleanup(dir, dentry);
+		if (!err)
+			err = ovl_cleanup(dir, dentry);
 	}
 
 	return err;