On 2024/3/12 21:14, Gael Donval wrote:
On Tue, 2024-03-12 at 20:43 +0800, Gao Xiang wrote:
...
Yes, but that needs a new version (maybe erofs-utils 1.8) though.
Of course!
Also I'm not sure how tar --xattrs works for "btrfs.compression",
does it also work in a relaxed mode? Could you give more inputs
& tries with "tar --xattrs"?
Tar just stores XATTRS as their own field. When I
$ tar --xattrs -cf foo.tar foo
and inspect the tar file it appears XATTRS are stored as arbitrary
SCHILY attributes:
./PaxHeaders/foo0000644000000000000000000000020114574033222010776
xustar0030 mtime=1710241426.458097911
30 atime=1710241426.458097911
30 ctime=1710241426.458097911
39 SCHILY.xattr.btrfs.compression=zstd
foo/0000755000175000017500000000000014574033222011551
5ustar00gdonvalgdonval
[...]
So tar blindly serializes everything.
Is there anything the BTRFS people could do to make their FS easier
to
work with?
Nope, I think it's unrelated to BTRFS but such xattrs are almost
meaningless for EROFS to keep (since they are their own xattrs.)
Ah that's interesting.
I suspect that in this instance the xattrs would not be useful at all
but other components like SELinux uses xattrs to perform MAC and who
knows what other xattrs-based schemes exist out there...
EROFS will keep common xattrs like selinux, but EROFS doesn't keep
btrfs. namespace (or other arbitrary xattr namespaces) like other
filesystems like ext4, xfs, f2fs, squashfs, etc. EROFS only supports
"user.", "trusted." and some "system." domains. In other words, If
EROFS has its own xattr namespace, I think other fses won't support
"erofs." too, also see:
https://lore.kernel.org/r/20230420092739.75464-1-o451686...@gmail.com
Because that is simple, you don't even know if the content in some
arbitrary namespace is static or dynamic. Or if it has some security
issue to keep them.
Would it make sense then to do what tar does and blindly serialize (and
expose) everything and provide a --xattrs-exclude=pattern in case
people want something more fine-grained?
As I said above.
Thanks,
Gao Xiang
The only main problem currently is that erofs tries to be smart about
xattrs and errors out when it does not know about something. It should
really be more graceful.>
Thanks,
Gaël
Thanks,
Gao Xiang
Gaël
Thanks,
Gao Xiang
Thanks for your help,
Gaël
