---

yaml
---
r: 318833
b: refs/heads/master
c: 2bc5565
h: refs/heads/master
i:
  318831: 1e8ba6f
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 063849eafda03edf6872a3728b4a98dcc86290c7
+refs/heads/master: 2bc5565286121d2a77ccd728eb3484dff2035b58

trunk/fs/btrfs/inode.c

@@ -4518,6 +4518,11 @@ int btrfs_dirty_inode(struct inode *inode)
 static int btrfs_update_time(struct inode *inode, struct timespec *now,
 			     int flags)
 {
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+
+	if (btrfs_root_readonly(root))
+		return -EROFS;
+
 	if (flags & S_VERSION)
 		inode_inc_iversion(inode);
 	if (flags & S_CTIME)

trunk/fs/inode.c

@@ -1551,6 +1551,8 @@ void touch_atime(struct path *path)
 	 * Btrfs), but since we touch atime while walking down the path we
 	 * really don't care if we failed to update the atime of the file,
 	 * so just ignore the return value.
+	 * We may also fail on filesystems that have the ability to make parts
+	 * of the fs read only, e.g. subvolumes in Btrfs.
 	 */
 	update_time(inode, &now, S_ATIME);
 	mnt_drop_write(mnt);