Hi all,
This is an initial prototype to improve XFS's prototype file
functionality in scenarios where FS reproducibility is important.
Currently, when populating a filesystem with a prototype file, all generated inodes
receive timestamps set to the creation time rather than preserving timestamps from
their source files.
This patchset extends the protofile handling to preserve original timestamps (atime,
mtime, ctime) across all inode types. The implementation is split into two parts:
- First patch extends xfs_protofile.in to track origin path references for directories,
character devices and symlinks, similar to what's already implemented for regular files.
- Second patch leverages these references to read timestamp metadata from source files
and populate it into the newly created inodes during filesystem creation.
At the moment, the new `xfs_protofile` generates a file that results
invalid for older `mkfs.xfs` implementations. Also this new implementation
is not compatible with older prototype files.
I can imagine that new protofiles not working with older `mkfs.xfs`
might not be a problem, but what about backward compatibility?
I didn't find references on prototype file compatibility, is a change
like this unwanted?
If so, what do you think of a versioned support for prototype files?
I was thinking something on the lines of:
- xfs_protofile
- if the new flag:
- set the first comment accordingly
- add the additional information
- else act as old one
- proto.c
- check if the doc starts with the comment `:origin-files enabled`
(for example)
- if so, this is the new format
- else old format
Eager to know your thoughts and ideas
Thanks
L.
Luca Di Maio (2):
xfs_proto: add origin also for directories, chardevs and symlinks
proto: read origin also for directories, chardevs and symlinks. copy
timestamps from origin.
mkfs/proto.c | 49 +++++++++++++++++++++++++++++++++++++++++++
mkfs/xfs_protofile.in | 12 +++++------
2 files changed, 55 insertions(+), 6 deletions(-)
--
2.49.0
