On 03/22/2018 01:15 PM, Austin S. Hemmelgarn wrote: > On 2018-03-21 16:38, Goffredo Baroncelli wrote: >> On 03/21/2018 12:47 PM, Austin S. Hemmelgarn wrote: >>> I agree as well, with the addendum that I'd love to see a new ioctl that does proper permissions checks. While letting rmdir(2) work for an empty subvolume with the appropriate permissions would be great (it will let rm -r work correctly), it doesn't address the usefulness of being able to just `btrfs subvolume delete` and not have to wait for the command to finish before you can reuse the name. >> >> How this could work ? >> >> If you want to check all the subvolumes files permissions, this will require some time: you need to traverse all the subvolume-filesystem; and only if all the checks are passed, you can delete the subvolume. >> >> Unfortunately I think that only two options exist: >> - don't check permissions, and you can quick remove a subvolume >> - check all the permissions, i.e. check all the files permissions, and only if all the permissions are OK, you can delete the subvolume. However this cannot be a "quick" subvolume delete > > Why exactly would you need to check everything? What I'm talking about is having behavior like `user_subvol_rm_allowed` be the default, with an additional check emulating the regular dentry removal check (namely that the user has appropriate permissions on the parent directory) so that people can't delete things like their own home directories. We're already _way_ beyond POSIX semantics here because we're debating the handling of permissions for an ioctl that takes a different fd than what it functionally operates on, so I see no reason whatsoever that we need to enforce POSIX semantics to that degree. > Why "user_subvol_rm_allowed" doesn't satisfy your needing ? Does not perform enough permission checking ? BR G.Baroncelli -- gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
