labeled disk.
This is complicated by the fact that BBSIZE is greater than the
PAGE_SIZE limit ioctl inflicts on arguments which are automatically
copied in.
As long as we don't need access to userland memory (copyin/out) we
can deal with the ioctl using g_callme() which executes it from the
GEOM event thread.
Once we need copyin/out, we need to return the bio with EDIRIOCTL
in order to make geom_dev call us back in the original process context
where copyin will work.
Unfortunately, that results in us getting called with Giant, so
we have to DROP_GIANT/PICKUP_GIANT around the code where we diddle
GEOMs internals.
Sometimes you just can't win...
... But it does make geom_bsd.c an almost complete example of the
GEOM beastiarium.
some trick is necessary to prevent further BSD geoms from attaching to
that. Our old trick was to make sure we don't attach to a geom from
the "BSD" class, but this doesn't work if an intermediary geom obscures
this fact. Instead, calculate the MD5 checksum of the label we target
and ask if anybody below us loves that label. If they do we don't.
Coded by: gordon.
don't take the detour over the I/O path to discover them using getattr(),
we can just pick them out directly.
Do note though, that for now they are only valid after the first open
of the underlying disk device due compatibility with the old disk_create()
API. This will change in the future so they will always be valid.
Sponsored by: DARPA & NAI Labs.
that this will make people use this for their future copy&paste operations.
Rework the detection of raw-disk offsets in disklabels. This actually
unearthed a number of bugs in the (now) previous version.
Also accept labels which don't have a magic RAW_PART, provided they don't
confuse us too much.
Change the order of our sanity-checks on labels found on disks to be more
robust.
Check against MAXPARTITIONS in our sanity-check and reject disklabels
we cannot cope with.
Create new g_bsd_modify() function to implment disklabel modifying
ioctls.
Implement DIOCSDINFO and DIOCWDINFO with the provision that the latter
still not writes your change back to disk. I didn't have the nerves
for that yet.
In the start routine, use g_call_me() for complex ioctls to prevent
sleeping.
Sponsored by: DARPA & NAI Labs.
with support for trying, doing and forcing.
This will eventually replace g_slice_addslice() which gets changed from
grabbing topology to requing it in this commit as well.
Sponsored by: DARPA & NAI Labs.
the relevant classes.
Some methods may implement various "magic spaces", this is reserved
or magic areas on the disk, set a side for various and sundry purposes.
A good example is the BSD disklabel and boot code on i386 which occupies
a total of four magic spaces: boot1, the disklabel, the padding behind
the disklabel and boot2. The reason we don't simply tell people to
write the appropriate stuff on the underlying device is that (some of)
the magic spaces might be real-time modifiable. It is for instance
possible to change a disklabel while partitions are open, provided
the open partitions do not get trampled in the process.
Sponsored by: DARPA & NAI Labs.
test and play with this.
This is not yet production quality and should be run only on dedicated
test boxes.
For people who want to develop transformations for GEOM there exist a
set of shims to run geom in userland (ask phk@freebsd.org).
Reports of all kinds to: phk@freebsd.org
Please include in report:
dmesg
sysctl debug.geomdot
sysctl debug.geomconf
Known significant limitations:
no kernel dump facility.
ioctls severely restricted.
Sponsored by: DARPA, NAI Labs
