ext4: switch to multigrain timestamps

Enable multigrain timestamps, which should ensure that there is an
apparent change to the timestamp whenever it has been written after
being actively observed via getattr.

For ext4, we only need to enable the FS_MGTIME flag.

Acked-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-12-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index b54c70e..cb1ff47 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -7279,7 +7279,7 @@ static struct file_system_type ext4_fs_type = {
        .init_fs_context        = ext4_init_fs_context,
        .parameters             = ext4_param_specs,
        .kill_sb                = kill_block_super,
-       .fs_flags               = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
+       .fs_flags               = FS_REQUIRES_DEV | FS_ALLOW_IDMAP | FS_MGTIME,
 };
 MODULE_ALIAS_FS("ext4");