On 13/11/2018 01:23, Andy Grover wrote: > On 11/9/18 12:21 PM, Andy Grover wrote: >> As mentioned elsewhere in dm-integrity.txt, creating a new integrity >> device requires creating a small integrity device on top of the base >> device that formats the base device, reading the provided data sectors >> out of the superblock, and then recreating the integrity device with the >> correct size. For this, userspace must know the offset, length, and >> endianness of the provided_data_sectors field in the superblock. >> >> Document all fields mentioned in the txt to include this, based on struct >> superblock in dm-integrity.c. Extra fields in struct superblock not >> already mentioned in the txt remain undocumented.> > In 4.19 I just noticed provided_data_sectors is now included in dm > status. I'm assuming that is now the preferred way for userspace to > discover this value? Thus making reading it from the on-disk superblock > unnecessary, and thus *documenting* the superblock format unnecessary. > Sounds good. Yes, I think Mikulas added this for this reason. We still read superblock in integritysetup to be compatible with the older targets, but you should not need it with 4.19+. > So please disregard this patch, although some different documentation > changes are probably now needed. Actually, meta_device option is not documented at all, and new status line is undocumented as well (I can send patch for this later). Anyway, I have another page that describes dm-integrity options (maintaining this while adding options to integritysetup, similar page exists for DMcrypt and DMverity) https://gitlab.com/cryptsetup/cryptsetup/wikis/DMIntegrity m. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
