It creates very huge provider (41PB) /dev/gzero.
On BIO_READ request it zero-fills bio_data and on BIO_WRITE it does nothing.
You can also set kern.geom.zero.clear sysctl to 0 to do nothing even for
BIO_READ.
I'm using it for performance testing where it is very helpful.
MFC after: 3 days
the given providers. Without even one of the configured components there
should be no way to get the secret.
Supported by: WHEEL Sp. z o.o.
http://www.wheel.pl
features. The gmirror(8) utility should be used for control of this class.
There is no manual page yet, but I'm working on it with keramida@.
Many useful tests provided by: simon (thank you!)
Some ideas from: scottl, simon, phk
This class is used for detecting volume labels on file systems:
UFS, MSDOSFS (FAT12, FAT16, FAT32) and ISO9660.
It also provide native labelization (there is no need for file system).
g_label_ufs.c is based on geom_vol_ffs from Gordon Tetlow.
g_label_msdos.c and g_label_iso9660.c are probably hacks, I just found
where volume labels are stored and I use those offsets here,
but with this class it should be easy to do it as it should be done by
someone who know how.
Implementing volume labels detection for other file systems also should
be trivial.
New providers are created in those directories:
/dev/ufs/ (UFS1, UFS2)
/dev/msdosfs/ (FAT12, FAT16, FAT32)
/dev/iso9660/ (ISO9660)
/dev/label/ (native labels, configured with glabel(8))
Manual page cleanups and some comments inside were submitted by
Simon L. Nielsen, who was, as always, very helpful. Thanks!
- Connect geom_stripe and geom_nop modules to the build.
- Connect STRIPE and NOP classes to the LINT build.
- Disconnect gconcat(8) from the build.
Supported by: Wheel - Open Technologies - http://www.wheel.pl
redundant paths to the same device.
This class reacts to a label in the first sector of the device,
which is created the following way:
# "0123456789abcdef012345..."
# "<----magic-----><-id-...>
echo "GEOM::FOX someid" | dd of=/dev/da0 conv=sync
NB: Since the fact that multiple disk devices are in fact the same
device is not known to GEOM, the geom taste/spoil process cannot
fully catch all corner cases and this module can therefore be
confused if you do the right wrong things.
NB: The disk level drivers need to do the right thing for this to
be useful, and that is not by definition currently the case.
