utimes: handle idmapped mounts

Enable the vfs_utimes() helper to handle idmapped mounts by passing down
the mount's user namespace. If the initial user namespace is passed
nothing changes so non-idmapped mounts will see identical behavior as
before.

Link: https://lore.kernel.org/r/20210121131959.646623-19-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/fs/utimes.c b/fs/utimes.c
index 4572b91..39f3560 100644 (file)
--- a/fs/utimes.c
+++ b/fs/utimes.c
@@ -62,7 +62,7 @@ int vfs_utimes(const struct path *path, struct timespec64 *times)
        }
 retry_deleg:
        inode_lock(inode);
-       error = notify_change(&init_user_ns, path->dentry, &newattrs,
+       error = notify_change(mnt_user_ns(path->mnt), path->dentry, &newattrs,
                              &delegated_inode);
        inode_unlock(inode);
        if (delegated_inode) {