2 files changed, 7 insertions, 0 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a7d1921ac76b..fcc65802f367 100644
--- a/fs/btrfs/inode.c
+++ b/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)
diff --git a/fs/inode.c b/fs/inode.c
index c99163b1b310..033529ecd242 100644
--- a/fs/inode.c
+++ b/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);