any open vnodes before proceeding. Make autounmound(8) use this flag.
Without it, even an unsuccessfull unmount causes filesystem flush,
which interferes with normal operation.
Reviewed by: kib@
Approved by: re (gjb@)
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D7047
or several hops we have segmentation fault because we overwrite the same
structure to store information for host and gateway.
Submitted by: Maryse Levavasseur <maryse.levavasseur@stormshield.eu>
Reworked by: hrs
Approved by: re (hrs)
Differential Revision: https://reviews.freebsd.org/D6980
associated) instance.
The result is that the packet is dropped without an indication
that smaller MTU is advisable, which is not optimal, but better
than a NULL pointer deref.
Approved by: re (glebius)
Adopt the OpenBSD syntax for setting and filtering on VLAN PCP values. This
introduces two new keywords: 'set prio' to set the PCP value, and 'prio' to
filter on it.
Reviewed by: allanjude, araujo
Approved by: re (gjb)
Obtained from: OpenBSD (mostly)
Differential Revision: https://reviews.freebsd.org/D6786
which refers to IEEE 802.1p class of service and maps to the frame
priority level.
Values in order of priority are: 1 (Background (lowest)),
0 (Best effort (default)), 2 (Excellent effort),
3 (Critical applications), 4 (Video, < 100ms latency),
5 (Video, < 10ms latency), 6 (Internetwork control) and
7 (Network control (highest)).
Example of usage:
root# ifconfig em0.1 create
root# ifconfig em0.1 vlanpcp 3
Note:
The review D801 includes the pf(4) part, but as discussed with kristof,
we won't commit the pf(4) bits for now.
The credits of the original code is from rwatson.
Differential Revision: https://reviews.freebsd.org/D801
Reviewed by: gnn, adrian, loos
Discussed with: rwatson, glebius, kristof
Tested by: many including Matthew Grooms <mgrooms__shrew.net>
Obtained from: pfSense
Relnotes: Yes
Correct switch between current and previous line buffers when
encountering a carriage return in the input.
CID: 1305719
Obtained from: OpenBSD (CVS rev. 1.30)
MFC after: 3 days
specified by the -f flag or IFCONFIG_FORMAT environment variable, the user
can request that inet4 subnet masks be printed in CIDR or dotted-quad
notation, in addition to the traditional hex output.
inet6 prefixes can be printed in CIDR as well.
For more documentation see the ifconfig(8) man page.
PR: 169072
Requested by: seanc, marcel, brd, many others
Reviewed by: gnn, jhb (earlier version)
Relnotes: yes
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D2856
This change makes the code use the POSIX basename() function. It has the
advantage that (if implemented correctly), it also imposes no restrict
on the pathname length.
Notice that I haven't added any error handling to the strdup() call. It
looks like none of the other calls to strdup() and malloc() performed by
this utility do it either.
Reviewed by: hrs
Differential Revision: https://reviews.freebsd.org/D6626
Connect it to userland (libmd, libcrypt, sbin/md5) and kernel (crypto.ko)
Support for skein as a ZFS checksum algorithm was introduced in r289422
but is disconnected because FreeBSD lacked a Skein implementation.
A further commit will enable it in ZFS.
Reviewed by: cem
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D6166
This implements SHA-512/256, which generates a 256 bit hash by
calculating the SHA-512 then truncating the result. A different initial
value is used, making the result different from the first 256 bits of
the SHA-512 of the same input. SHA-512 is ~50% faster than SHA-256 on
64bit platforms, so the result is a faster 256 bit hash.
The main goal of this implementation is to enable support for this
faster hashing algorithm in ZFS. The feature was introduced into ZFS
in r289422, but is disconnected because SHA-512/256 support was missing.
A further commit will enable it in ZFS.
This is the follow on to r292782
Reviewed by: cem
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D6061
Centre for Advanced Internet Architectures
Implementing AQM in FreeBSD
* Overview <http://caia.swin.edu.au/freebsd/aqm/index.html>
* Articles, Papers and Presentations
<http://caia.swin.edu.au/freebsd/aqm/papers.html>
* Patches and Tools <http://caia.swin.edu.au/freebsd/aqm/downloads.html>
Overview
Recent years have seen a resurgence of interest in better managing
the depth of bottleneck queues in routers, switches and other places
that get congested. Solutions include transport protocol enhancements
at the end-hosts (such as delay-based or hybrid congestion control
schemes) and active queue management (AQM) schemes applied within
bottleneck queues.
The notion of AQM has been around since at least the late 1990s
(e.g. RFC 2309). In recent years the proliferation of oversized
buffers in all sorts of network devices (aka bufferbloat) has
stimulated keen community interest in four new AQM schemes -- CoDel,
FQ-CoDel, PIE and FQ-PIE.
The IETF AQM working group is looking to document these schemes,
and independent implementations are a corner-stone of the IETF's
process for confirming the clarity of publicly available protocol
descriptions. While significant development work on all three schemes
has occured in the Linux kernel, there is very little in FreeBSD.
Project Goals
This project began in late 2015, and aims to design and implement
functionally-correct versions of CoDel, FQ-CoDel, PIE and FQ_PIE
in FreeBSD (with code BSD-licensed as much as practical). We have
chosen to do this as extensions to FreeBSD's ipfw/dummynet firewall
and traffic shaper. Implementation of these AQM schemes in FreeBSD
will:
* Demonstrate whether the publicly available documentation is
sufficient to enable independent, functionally equivalent implementations
* Provide a broader suite of AQM options for sections the networking
community that rely on FreeBSD platforms
Program Members:
* Rasool Al Saadi (developer)
* Grenville Armitage (project lead)
Acknowledgements:
This project has been made possible in part by a gift from the
Comcast Innovation Fund.
Submitted by: Rasool Al-Saadi <ralsaadi@swin.edu.au>
X-No objection: core
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D6388
Change default regulatory domain from DEBUG (no limitations;
exposes all device channels) to FCC; as a result, newly created wireless
interface with default settings will have less chances to violate
country-specific regulations.
This change will not affect drivers with pre-initialized regdomain
structure (currentry ath(4) and mwl(4)); in that case, the default
channel list must correspond to the default regdomain / country setting.
You can switch to another regdomain / country via corresponding
ifconfig(8) options; the driver must implement ic_getradiocaps()
method to restore full channel list.
Full country / regdomain list may be obtained via
'ifconfig <iface> list countries' command.
Example: change country to Germany:
ifconfig wlan0 down # all wlans on the device must be down
ifconfig wlan0 country DE
ifconfig wlan0 up
# wpa_supplicant(8), dhclient(8) etc
At the creation time:
ifconfig wlan0 create wlandev wpi0 country DE
To make changes permanent add the following line to the rc.conf(5):
create_args_wlan0="country DE"
Tested with
- Intel 3945BG (wpi(4)).
- WUSB54GC (rum(4)).
Reviewed by: adrian
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D6228
defects. When shifting an unsigned byte into the upper 8 bits of
an int and the resulting value is greater than 0x7FFFFFF, the result
will be sign extended when converting to a 64 bit unsigned long.
Fix by casting to (uint64_t) before the shift.
Reported by: Coverity
CID: 1356044, 1356045
Reviewed by: ken
overflow defect. Use the new CCB_CLEAR_ALL_EXCEPT_HDR() macro
instead of the calling bzero() on the pointer to the header used
as an array and indexed by 1.
Don't leak a buffer after executing "goto restart_report" by
overwriting its pointer with the results of another calloc().
Be sure to clear the buffer before reusing it. (CID 1356042)
Reported by: Coverity
CID: 1356022, 1356034, 1356023, 1356035, 1356042
Reviewed by: ken
The currently used idiom for clearing the part of a ccb after its
header generates one or two Coverity errors for each time it is
used. All instances generate an Out-of-bounds access (ARRAY_VS_SINGLETON)
error because of the treatment of the header as a two element array,
with a pointer to the non-existent second element being passed as
the starting address to bzero(). Some instances also alsp generate
Out-of-bounds access (OVERRUN) errors, probably because the space
being cleared is larger than the sizeofstruct ccb_hdr).
In addition, this idiom is difficult for humans to understand and
it is error prone. The user has to chose the proper struct ccb_*
type (which does not appear in the surrounding code) for the sizeof()
in the length calculation. I found several instances where the
length was incorrect, which could cause either an actual out of
bounds write, or incompletely clear the ccb.
A better way is to write the code to clear the ccb itself starting
at sizeof(ccb_hdr) bytes from the start of the ccb, and calculate
the length based on the specific type of struct ccb_* being cleared
as specified by the union ccb member being used. The latter can
normally be seen in the nearby code. This is friendlier for Coverity
and other static analysis tools because they will see that the
intent is to clear the trailing part of the ccb.
Wrap all of the boilerplate code in a convenient macro that only
requires a pointer to the desired union ccb member (or a pointer
to the union ccb itself) as an argument.
Reported by: Coverity
CID: 1007578, 1008684, 1009724, 1009773, 1011304, 1011306
CID: 1011307, 1011308, 1011309, 1011310, 1011311, 1011312
CID: 1011313, 1011314, 1011315, 1011316, 1011317, 1011318
CID: 1011319, 1011320, 1011321, 1011322, 1011324, 1011325
CID: 1011326, 1011327, 1011328, 1011329, 1011330, 1011374
CID: 1011390, 1011391, 1011392, 1011393, 1011394, 1011395
CID: 1011396, 1011397, 1011398, 1011399, 1011400, 1011401
CID: 1011402, 1011403, 1011404, 1011405, 1011406, 1011408
CID: 1011409, 1011410, 1011411, 1011412, 1011413, 1011414
CID: 1017461, 1018387, 1086860, 1086874, 1194257, 1229897
CID: 1229968, 1306229, 1306234, 1331282, 1331283, 1331294
CID: 1331295, 1331535, 1331536, 1331539, 1331540, 1341623
CID: 1341624, 1341637, 1341638, 1355264, 1355324
Reviewed by: scottl, ken, delphij, imp
MFH: 1 month
Differential Revision: https://reviews.freebsd.org/D6496
This change includes support for SCSI SMR drives (which conform to the
Zoned Block Commands or ZBC spec) and ATA SMR drives (which conform to
the Zoned ATA Command Set or ZAC spec) behind SAS expanders.
This includes full management support through the GEOM BIO interface, and
through a new userland utility, zonectl(8), and through camcontrol(8).
This is now ready for filesystems to use to detect and manage zoned drives.
(There is no work in progress that I know of to use this for ZFS or UFS, if
anyone is interested, let me know and I may have some suggestions.)
Also, improve ATA command passthrough and dispatch support, both via ATA
and ATA passthrough over SCSI.
Also, add support to camcontrol(8) for the ATA Extended Power Conditions
feature set. You can now manage ATA device power states, and set various
idle time thresholds for a drive to enter lower power states.
Note that this change cannot be MFCed in full, because it depends on
changes to the struct bio API that break compatilibity. In order to
avoid breaking the stable API, only changes that don't touch or depend on
the struct bio changes can be merged. For example, the camcontrol(8)
changes don't depend on the new bio API, but zonectl(8) and the probe
changes to the da(4) and ada(4) drivers do depend on it.
Also note that the SMR changes have not yet been tested with an actual
SCSI ZBC device, or a SCSI to ATA translation layer (SAT) that supports
ZBC to ZAC translation. I have not yet gotten a suitable drive or SAT
layer, so any testing help would be appreciated. These changes have been
tested with Seagate Host Aware SATA drives attached to both SAS and SATA
controllers. Also, I do not have any SATA Host Managed devices, and I
suspect that it may take additional (hopefully minor) changes to support
them.
Thanks to Seagate for supplying the test hardware and answering questions.
sbin/camcontrol/Makefile:
Add epc.c and zone.c.
sbin/camcontrol/camcontrol.8:
Document the zone and epc subcommands.
sbin/camcontrol/camcontrol.c:
Add the zone and epc subcommands.
Add auxiliary register support to build_ata_cmd(). Make sure to
set the CAM_ATAIO_NEEDRESULT, CAM_ATAIO_DMA, and CAM_ATAIO_FPDMA
flags as appropriate for ATA commands.
Add a new get_ata_status() function to parse ATA result from SCSI
sense descriptors (for ATA passthrough over SCSI) and ATA I/O
requests.
sbin/camcontrol/camcontrol.h:
Update the build_ata_cmd() prototype
Add get_ata_status(), zone(), and epc().
sbin/camcontrol/epc.c:
Support for ATA Extended Power Conditions features. This includes
support for all features documented in the ACS-4 Revision 12
specification from t13.org (dated February 18, 2016).
The EPC feature set allows putting a drive into a power power mode
immediately, or setting timeouts so that the drive will
automatically enter progressively lower power states after various
idle times.
sbin/camcontrol/fwdownload.c:
Update the firmware download code for the new build_ata_cmd()
arguments.
sbin/camcontrol/zone.c:
Implement support for Shingled Magnetic Recording (SMR) drives
via SCSI Zoned Block Commands (ZBC) and ATA Zoned Device ATA
Command Set (ZAC).
These specs were developed in concert, and are functionally
identical. The primary differences are due to SCSI and ATA
differences. (SCSI is big endian, ATA is little endian, for
example.)
This includes support for all commands defined in the ZBC and
ZAC specs.
sys/cam/ata/ata_all.c:
Decode a number of additional ATA command names in ata_op_string().
Add a new CCB building function, ata_read_log().
Add ata_zac_mgmt_in() and ata_zac_mgmt_out() CCB building
functions. These support both DMA and NCQ encapsulation.
sys/cam/ata/ata_all.h:
Add prototypes for ata_read_log(), ata_zac_mgmt_out(), and
ata_zac_mgmt_in().
sys/cam/ata/ata_da.c:
Revamp the ada(4) driver to support zoned devices.
Add four new probe states to gather information needed for zone
support.
Add a new adasetflags() function to avoid duplication of large
blocks of flag setting between the async handler and register
functions.
Add new sysctl variables that describe zone support and paramters.
Add support for the new BIO_ZONE bio, and all of its subcommands:
DISK_ZONE_OPEN, DISK_ZONE_CLOSE, DISK_ZONE_FINISH, DISK_ZONE_RWP,
DISK_ZONE_REPORT_ZONES, and DISK_ZONE_GET_PARAMS.
sys/cam/scsi/scsi_all.c:
Add command descriptions for the ZBC IN/OUT commands.
Add descriptions for ZBC Host Managed devices.
Add a new function, scsi_ata_pass() to do ATA passthrough over
SCSI. This will eventually replace scsi_ata_pass_16() -- it
can create the 12, 16, and 32-byte variants of the ATA
PASS-THROUGH command, and supports setting all of the
registers defined as of SAT-4, Revision 5 (March 11, 2016).
Change scsi_ata_identify() to use scsi_ata_pass() instead of
scsi_ata_pass_16().
Add a new scsi_ata_read_log() function to facilitate reading
ATA logs via SCSI.
sys/cam/scsi/scsi_all.h:
Add the new ATA PASS-THROUGH(32) command CDB. Add extended and
variable CDB opcodes.
Add Zoned Block Device Characteristics VPD page.
Add ATA Return SCSI sense descriptor.
Add prototypes for scsi_ata_read_log() and scsi_ata_pass().
sys/cam/scsi/scsi_da.c:
Revamp the da(4) driver to support zoned devices.
Add five new probe states, four of which are needed for ATA
devices.
Add five new sysctl variables that describe zone support and
parameters.
The da(4) driver supports SCSI ZBC devices, as well as ATA ZAC
devices when they are attached via a SCSI to ATA Translation (SAT)
layer. Since ZBC -> ZAC translation is a new feature in the T10
SAT-4 spec, most SATA drives will be supported via ATA commands
sent via the SCSI ATA PASS-THROUGH command. The da(4) driver will
prefer the ZBC interface, if it is available, for performance
reasons, but will use the ATA PASS-THROUGH interface to the ZAC
command set if the SAT layer doesn't support translation yet.
As I mentioned above, ZBC command support is untested.
Add support for the new BIO_ZONE bio, and all of its subcommands:
DISK_ZONE_OPEN, DISK_ZONE_CLOSE, DISK_ZONE_FINISH, DISK_ZONE_RWP,
DISK_ZONE_REPORT_ZONES, and DISK_ZONE_GET_PARAMS.
Add scsi_zbc_in() and scsi_zbc_out() CCB building functions.
Add scsi_ata_zac_mgmt_out() and scsi_ata_zac_mgmt_in() CCB/CDB
building functions. Note that these have return values, unlike
almost all other CCB building functions in CAM. The reason is
that they can fail, depending upon the particular combination
of input parameters. The primary failure case is if the user
wants NCQ, but fails to specify additional CDB storage. NCQ
requires using the 32-byte version of the SCSI ATA PASS-THROUGH
command, and the current CAM CDB size is 16 bytes.
sys/cam/scsi/scsi_da.h:
Add ZBC IN and ZBC OUT CDBs and opcodes.
Add SCSI Report Zones data structures.
Add scsi_zbc_in(), scsi_zbc_out(), scsi_ata_zac_mgmt_out(), and
scsi_ata_zac_mgmt_in() prototypes.
sys/dev/ahci/ahci.c:
Fix SEND / RECEIVE FPDMA QUEUED in the ahci(4) driver.
ahci_setup_fis() previously set the top bits of the sector count
register in the FIS to 0 for FPDMA commands. This is okay for
read and write, because the PRIO field is in the only thing in
those bits, and we don't implement that further up the stack.
But, for SEND and RECEIVE FPDMA QUEUED, the subcommand is in that
byte, so it needs to be transmitted to the drive.
In ahci_setup_fis(), always set the the top 8 bits of the
sector count register. We need it in both the standard
and NCQ / FPDMA cases.
sys/geom/eli/g_eli.c:
Pass BIO_ZONE commands through the GELI class.
sys/geom/geom.h:
Add g_io_zonecmd() prototype.
sys/geom/geom_dev.c:
Add new DIOCZONECMD ioctl, which allows sending zone commands to
disks.
sys/geom/geom_disk.c:
Add support for BIO_ZONE commands.
sys/geom/geom_disk.h:
Add a new flag, DISKFLAG_CANZONE, that indicates that a given
GEOM disk client can handle BIO_ZONE commands.
sys/geom/geom_io.c:
Add a new function, g_io_zonecmd(), that handles execution of
BIO_ZONE commands.
Add permissions check for BIO_ZONE commands.
Add command decoding for BIO_ZONE commands.
sys/geom/geom_subr.c:
Add DDB command decoding for BIO_ZONE commands.
sys/kern/subr_devstat.c:
Record statistics for REPORT ZONES commands. Note that the
number of bytes transferred for REPORT ZONES won't quite match
what is received from the harware. This is because we're
necessarily counting bytes coming from the da(4) / ada(4) drivers,
which are using the disk_zone.h interface to communicate up
the stack. The structure sizes it uses are slightly different
than the SCSI and ATA structure sizes.
sys/sys/ata.h:
Add many bit and structure definitions for ZAC, NCQ, and EPC
command support.
sys/sys/bio.h:
Convert the bio_cmd field to a straight enumeration. This will
yield more space for additional commands in the future. After
change r297955 and other related changes, this is now possible.
Converting to an enumeration will also prevent use as a bitmask
in the future.
sys/sys/disk.h:
Define the DIOCZONECMD ioctl.
sys/sys/disk_zone.h:
Add a new API for managing zoned disks. This is very close to
the SCSI ZBC and ATA ZAC standards, but uses integers in native
byte order instead of big endian (SCSI) or little endian (ATA)
byte arrays.
This is intended to offer to the complete feature set of the ZBC
and ZAC disk management without requiring the application developer
to include SCSI or ATA headers. We also use one set of headers
for ioctl consumers and kernel bio-level consumers.
sys/sys/param.h:
Bump __FreeBSD_version for sys/bio.h command changes, and inclusion
of SMR support.
usr.sbin/Makefile:
Add the zonectl utility.
usr.sbin/diskinfo/diskinfo.c
Add disk zoning capability to the 'diskinfo -v' output.
usr.sbin/zonectl/Makefile:
Add zonectl makefile.
usr.sbin/zonectl/zonectl.8
zonectl(8) man page.
usr.sbin/zonectl/zonectl.c
The zonectl(8) utility. This allows managing SCSI or ATA zoned
disks via the disk_zone.h API. You can report zones, reset write
pointers, get parameters, etc.
Sponsored by: Spectra Logic
Differential Revision: https://reviews.freebsd.org/D6147
Reviewed by: wblock (documentation)
A DHCP client identifier is simply the hardware type (one byte) concatenated
with the hardware address (some variable number of bytes, but at most 16).
Limit the size of the temporary buffer to match and the rest of the
calculations shake out correctly.
This is a follow-up to the incorrect r299512, reverted in r300172.
CIDs: 1008682, 1305550
Sponsored by: EMC / Isilon Storage Division
It broke client identifiers because I misunderstood the intent of the code.
There is still a minor issue detected by Coverity (at least, I can't find where
the code proves it isn't an issue). I'll follow up with a better fix for the
CIDs.
Reported by: Ian FREISLICH
Sponsored by: EMC / Isilon Storage Division
objects with the same name in different sets.
Add optional manage_sets() callback to objects rewriting framework.
It is intended to implement handler for moving and swapping named
object's sets. Add ipfw_obj_manage_sets() function that implements
generic sets handler. Use new callback to implement sets support for
lookup tables.
External actions objects are global and they don't support sets.
Modify eaction_findbyname() to reflect this.
ipfw(8) now may fail to move rules or sets, because some named objects
in target set may have conflicting names.
Note that ipfw_obj_ntlv type was changed, but since lookup tables
actually didn't support sets, this change is harmless.
Obtained from: Yandex LLC
Sponsored by: Yandex LLC
that it is NUL terminated. Additional NUL padding is not required
for short names.
Use sizeof(destination) in a few places instead of IFNAMSIZ.
Cast afp->af_ridreq and afp->af_addreq to make the intent of
the code more obvious.
Reported by: Coverity
CID: 1009628, 1009630, 1009631, 1009632, 1009633, 1009635, 1009638
CID: 1009639, 1009640, 1009641, 1009642, 1009643, 1009644, 1009645
CID: 1009646, 1009647, 1010049, 1010050, 1010051, 1010052, 1010053
CID: 1010054, 1011293, 1011294, 1011295, 1011296, 1011297, 1011298
CID: 1011299, 1305821, 1351720, 1351721
MFC after: 1 week
Use arc4random_uniform() when the desired random number upper bound
is not a power of two.
While here, we don't need srandom() and friends anymore.
Obtained from: OpenBSD (CVS rev. 1.20)
The reports and fixes are straightforward but it's nice to be able
to confirm against NetBSD.
CID: 271080, 272306, 272307
Obtained from: NetBSD (CVS ref. 1.21 - 1.23)
MFC after: 2 weeks.
For the multihomed case, ifp be used after being freed. NULL the value
after freeing it and avoid getting into the branch without reassigning
a new value.
CID: 272671
Obtained from: NetBSD
MFC after: 2 weeks
There was some confusion about how to limit a hardware address to at most 16
bytes. In some cases it would overrun a byte off the end of the array.
Correct the types and rectify the overrun.
Reported by: Coverity
CIDs: 1008682, 1305550
Sponsored by: EMC / Isilon Storage Division
Maybe this case is impossible. Either way, when attempting to "/dev/"-prefix a
non-global device name, check that we do not overrun the f_mntfromname buffer.
In this case, truncating (with strlcpy or similar) would not be useful, since
the f_mntfromname result of getmntpt() is passed directly to open(2) later.
Reported by: Coverity
CID: 1006789
Sponsored by: EMC / Isilon Storage Division
it via kern.proc.pathname sysctl(2). In some cases - booting from NFS
or rerooting after replacing the init binary with a new one - the sysctl
would fail. In other cases - after upgrading, which moves the old init
to /sbin/init.bak - it would return /sbin/init.bak, which is the actual
path of the running init, instead of /sbin/init.
Reported by: Melissa Jenkins <melissa-freebsd at littlebluecar.co.uk>, jilles@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
this by myself, but apparently it sometimes happens when rerooting from
single user mode.
Reported by: jilles@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
to make the system "notice" the updated disk size.
(Relnotes, since I've forget to set it for "camcontrol reprobe", and
it's worth mentioning.)
MFC after: 1 month
Relnotes: yes
Sponsored by: The FreeBSD Foundation
This makes it possible to manually force updating capacity data
after the disk got resized. Without it it might be neccessary to
reboot before FreeBSD notices updated disk size under eg VMWare.
Discussed with: imp@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D6108
