You can change it - though I expect that anyone who will want to parse the superblock will read the file dm-integrity.c anyway. There's also a new field recalc_sector that says where to resume automatic recalculation. Mikulas On Fri, 9 Nov 2018, 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. > > Signed-off-by: Andy Grover <agrover@xxxxxxxxxx> > --- > Documentation/device-mapper/dm-integrity.txt | 26 ++++++++++++-------- > 1 file changed, 16 insertions(+), 10 deletions(-) > > diff --git a/Documentation/device-mapper/dm-integrity.txt b/Documentation/device-mapper/dm-integrity.txt > index 297251b0d2d5..3d28328f16c1 100644 > --- a/Documentation/device-mapper/dm-integrity.txt > +++ b/Documentation/device-mapper/dm-integrity.txt > @@ -158,16 +158,22 @@ The layout of the formatted block device: > storing LUKS metadata or for other purpose), the size of the reserved > area is specified in the target arguments > * superblock (4kiB) > - * magic string - identifies that the device was formatted > - * version > - * log2(interleave sectors) > - * integrity tag size > - * the number of journal sections > - * provided data sectors - the number of sectors that this target > - provides (i.e. the size of the device minus the size of all > - metadata and padding). The user of this target should not send > - bios that access data beyond the "provided data sectors" limit. > - * flags - a flag is set if journal_mac is used > + > +offset and length in bytes. All values little-endian. > + > +offset length description > +0 8 magic string - identifies that the device was formatted > +8 1 version > +9 1 log2(interleave sectors) > +10 2 integrity tag size > +12 4 the number of journal sections > +16 8 provided data sectors - the number of sectors that this > + target provides (i.e. the size of the device minus the size of > + all metadata and padding). The user of this target should not > + send bios that access data beyond the "provided data sectors" > + limit. > +24 4 flags - a flag is set if journal_mac is used > + > * journal > The journal is divided into sections, each section contains: > * metadata area (4kiB), it contains journal entries > -- > 2.17.2 > -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
