Merge branch 'work.gfs2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull gfs2 setattr updates from Al Viro:
 "Make it possible for filesystems to use a generic 'may_setattr()' and
  switch gfs2 to using it"

* 'work.gfs2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  gfs2: Switch to may_setattr in gfs2_setattr
  fs: Move notify_change permission checks into may_setattr

Author: torvalds

fs/attr.c

@@ -249,6 +249,34 @@ void setattr_copy(struct user_namespace *mnt_userns, struct inode *inode,
 }
 EXPORT_SYMBOL(setattr_copy);
 
+int may_setattr(struct user_namespace *mnt_userns, struct inode *inode,
+		unsigned int ia_valid)
+{
+	int error;
+
+	if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) {
+		if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
+			return -EPERM;
+	}
+
+	/*
+	 * If utimes(2) and friends are called with times == NULL (or both
+	 * times are UTIME_NOW), then we need to check for write permission
+	 */
+	if (ia_valid & ATTR_TOUCH) {
+		if (IS_IMMUTABLE(inode))
+			return -EPERM;
+
+		if (!inode_owner_or_capable(mnt_userns, inode)) {
+			error = inode_permission(mnt_userns, inode, MAY_WRITE);
+			if (error)
+				return error;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL(may_setattr);
+
 /**
  * notify_change - modify attributes of a filesytem object
  * @mnt_userns:	user namespace of the mount the inode was found from
@@ -290,25 +318,9 @@ int notify_change(struct user_namespace *mnt_userns, struct dentry *dentry,
 
 	WARN_ON_ONCE(!inode_is_locked(inode));
 
-	if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) {
-		if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
-			return -EPERM;
-	}
-
-	/*
-	 * If utimes(2) and friends are called with times == NULL (or both
-	 * times are UTIME_NOW), then we need to check for write permission
-	 */
-	if (ia_valid & ATTR_TOUCH) {
-		if (IS_IMMUTABLE(inode))
-			return -EPERM;
-
-		if (!inode_owner_or_capable(mnt_userns, inode)) {
-			error = inode_permission(mnt_userns, inode, MAY_WRITE);
-			if (error)
-				return error;
-		}
-	}
+	error = may_setattr(mnt_userns, inode, ia_valid);
+	if (error)
+		return error;
 
 	if ((ia_valid & ATTR_MODE)) {
 		umode_t amode = attr->ia_mode;

fs/gfs2/inode.c

@@ -1985,8 +1985,8 @@ static int gfs2_setattr(struct user_namespace *mnt_userns,
 	if (error)
 		goto out;
 
-	error = -EPERM;
-	if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
+	error = may_setattr(&init_user_ns, inode, attr->ia_valid);
+	if (error)
 		goto error;
 
 	error = setattr_prepare(&init_user_ns, dentry, attr);

include/linux/fs.h

@@ -3439,6 +3439,8 @@ extern int buffer_migrate_page_norefs(struct address_space *,
 #define buffer_migrate_page_norefs NULL
 #endif
 
+int may_setattr(struct user_namespace *mnt_userns, struct inode *inode,
+		unsigned int ia_valid);
 int setattr_prepare(struct user_namespace *, struct dentry *, struct iattr *);
 extern int inode_newsize_ok(const struct inode *, loff_t offset);
 void setattr_copy(struct user_namespace *, struct inode *inode,