Re: [man-pages RFC PATCH v4] statx, inode: document the new STATX_INO_VERSION field

From: Florian Weimer
Date: Mon Sep 12 2022 - 08:13:28 EST

* Jeff Layton:

> To do this we'd need 2 64-bit fields in the on-disk and in-memory
> superblocks for ext4, xfs and btrfs. On the first mount after a crash,
> the filesystem would need to bump s_version_max by the significant
> increment (2^40 bits or whatever). On a "clean" mount, it wouldn't need
> to do that.
> Would there be a way to ensure that the new s_version_max value has made
> it to disk? Bumping it by a large value and hoping for the best might be
> ok for most cases, but there are always outliers, so it might be
> worthwhile to make an i_version increment wait on that if necessary.

How common are unclean shutdowns in practice? Do ex64/XFS/btrfs keep
counters in the superblocks for journal replays that can be read easily?

Several useful i_version applications could be negatively impacted by
frequent i_version invalidation.