The purpose of the PMBR is to have the disk appear in use to GPT
unaware utilities (like fdisk). However, if the PMBR has been changed
by a GPT unaware utlity then we must assume that this was deliberate
(as it involved removal of the special slice) and we should not treat
the unmodified GPT-specific sectors as being valid. By lowering the
probe priority in that case, the MBR scheme will take precedence and
the kernel will end up using the MBR and not the GPT. We will still
use the GPT if the kernel does not support the MBR scheme.
When safety requirements are met, it allows to avoid passing I/O requests
to GEOM g_up/g_down thread, executing them directly in the caller context.
That allows to avoid CPU bottlenecks in g_up/g_down threads, plus avoid
several context switches per I/O.
The defined now safety requirements are:
- caller should not hold any locks and should be reenterable;
- callee should not depend on GEOM dual-threaded concurency semantics;
- on the way down, if request is unmapped while callee doesn't support it,
the context should be sleepable;
- kernel thread stack usage should be below 50%.
To keep compatibility with GEOM classes not meeting above requirements
new provider and consumer flags added:
- G_CF_DIRECT_SEND -- consumer code meets caller requirements (request);
- G_CF_DIRECT_RECEIVE -- consumer code meets callee requirements (done);
- G_PF_DIRECT_SEND -- provider code meets caller requirements (done);
- G_PF_DIRECT_RECEIVE -- provider code meets callee requirements (request).
Capable GEOM class can set them, allowing direct dispatch in cases where
it is safe. If any of requirements are not met, request is queued to
g_up or g_down thread same as before.
Such GEOM classes were reviewed and updated to support direct dispatch:
CONCAT, DEV, DISK, GATE, MD, MIRROR, MULTIPATH, NOP, PART, RAID, STRIPE,
VFS, ZERO, ZFS::VDEV, ZFS::ZVOL, all classes based on g_slice KPI (LABEL,
MAP, FLASHMAP, etc).
To declare direct completion capability disk(9) KPI got new flag equivalent
to G_PF_DIRECT_SEND -- DISKFLAG_DIRECT_COMPLETION. da(4) and ada(4) disk
drivers got it set now thanks to earlier CAM locking work.
This change more then twice increases peak block storage performance on
systems with manu CPUs, together with earlier CAM locking changes reaching
more then 1 million IOPS (512 byte raw reads from 16 SATA SSDs on 4 HBAs to
256 user-level threads).
Sponsored by: iXsystems, Inc.
MFC after: 2 months
When parent provider has been resized, the scheme specific G_PART_RESIZE
method does an update of scheme's metadata. But all changes are not saved
to disk, until `gpart commit` will be called.
Discussed with: trasz
MFC after: 1 month
the GEOM_PART. Instead of just using number of entries from the GPT
header, calculate this limit based on the reserved space between
GPT header and first available LBA.
MFC after: 2 weeks
being defined in <sys/diskmbr.h>. Instead give the symbols here a
"PC98_" prefix. This way, both <sys/diskmbr.h> and <sys/diskpc98.h>
can be included in the same C source file.
The renaming is trivial. The only gotcha is that DOSBBSECTOR is
also redefined from 0 to 1. This because DOSBBSECTOR was always
used in conjunction with an addition of 1. The PC98_BBSECTOR symbol
is defined as 1 and the expression is simplified.
Note: it is not believed that ports are seriously impacted; or at
all for that matter.
Approved by: nyan@
This allows setting attributes on tables. One simply does not provide
an index in that case. Otherwise the entry corresponding the index has
the attribute set or unset.
Use this change to fix a relatively longstanding bug in our GPT scheme
that's the result of rev 198097 (relatively harmless) followed by rev
237057 (damaging). The damaging part being that our GPT scheme always
has the active flag set on the PMBR slice. This is in violation with
EFI. Existing EFI implementions for both x86 and ia64 reject the GPT.
As such, GPT disks created by us aren't usable under EFI because of
that.
After this change, GPT disks never have the active flag set on the PMBR
slice. In order to make the GPT disk bootable under some x86 BIOSes,
the reason of rev 198097, one must now set the active attribute on the
gpt table. The kernel will apply this to the PMBR slice For (S)ATA:
gpart set -a active ada0
To fix an existing GPT disk that has the active flag set in the PMBR,
and that does not need the flag, use (again for (S)ATA):
gpart unset -a active ada0
The EBR, MBR & PC98 schemes, which also impement at least 1 attribute,
now check to make sure the entry passed is valid. They do not have
attributes that apply to the table.
It includes three parts:
1) Modifications to CAM to detect media media changes and report them to
disk(9) layer. For modern SATA (and potentially UAS) devices it utilizes
Asynchronous Notification mechanism to receive events from hardware.
Active polling with TEST UNIT READY commands with 3 seconds period is used
for incapable hardware. After that both CD and DA drivers work the same way,
detecting two conditions: "NOT READY: Medium not present" after medium was
detected previously, and "UNIT ATTENTION: Not ready to ready change, medium
may have changed". First one reported to disk(9) as media removal, second
as media insert/change. To reliably receive second event new
AC_UNIT_ATTENTION async added to make UAs broadcasted to all periphs by
generic error handling code in cam_periph_error().
2) Modifications to GEOM core to handle media remove and change events.
Media removal handled by spoiling all consumers attached to the provider.
Media change event also schedules provider retaste after spoiling to probe
new media. New flag G_CF_ORPHAN was added to consumers to reflect that
consumer is in process of destruction. It allows retaste to create new
geom instance of the same class, while previous one is still dying.
3) Modifications to some GEOM classes: DEV -- to report media change
events to devd; VFS -- to handle spoiling same as orphan to prevent
accessing replaced media. PART class already handles spoiling alike to
orphan.
Reviewed by: silence on geom@ and scsi@
Tested by: avg
Sponsored by: iXsystems, Inc. / PC-BSD
MFC after: 2 months
KLD is preloaded with loader(8) and leads to infinity loops.
Also do not return EEXIST error code from MOD_LOAD handler, because
we have undocumented(?) ability replace kernel's module with preloaded one.
And if we have so, then preloaded module will be initialized first.
Thus error in MOD_LOAD handler will be triggered for the kernel.
PR: kern/165573
MFC after: 3 weeks
scheme. The LDM is a logical volume manager for MS Windows NT and it
is also known as dynamic volumes. It supports about 2000 partitions
and also provides the capability for software RAID implementations.
This version implements only partitioning scheme capability and based
on the linux-ntfs project documentation and several publications across
the Web. NOTE: JBOD, RAID0 and RAID5 volumes aren't supported.
An access to the LDM metadata is read-only. When LDM is on the disk
partitioned with MBR we can also destroy metadata. For the GPT
partitioned disks destroy action is not supported.
Reviewed by: ivoras (previous version)
MFC after: 1 month
It's not clear to a user what they should do after seeing the "geometry
does not match label" kernel message, and it does not appear to present
a problem in practice. Thus, just remove the messages.
Approved by: marcel
types 0x05 and 0x0f, but 0x05 is preferred and used when partition is
created with "gpart add -t ebr ...".
This should keep EBR partitions accessible after r231754 for those,
who have EBR on the partition with type 0x0f.
don't try probe and create EBR scheme when parent partition type
is not "ebr". This fixes error messages about corrupted EBR for
some partitions where is actually another partition scheme.
NOTE: if you have EBR on the partition with different than "ebr"
(0x05) type, then you will lost access to partitions until it will be
changed.
MFC after: 2 weeks
as the system dump device. This was already allowed for GPT. The Linux
swap metadata at the beginning of the partition should not be disturbed
because the crash dump is written at the end.
Reviewed by: alfred, pjd, marcel
MFC after: 2 weeks
have reserved free space in the APM area.
Also instead of one write request per each APM entry, use MAXPHY
sized writes when we are updating APM.
MFC after: 1 month
The SYSCTL_NODE macro defines a list that stores all child-elements of
that node. If there's no SYSCTL_DECL macro anywhere else, there's no
reason why it shouldn't be static.
providers and consumers will be destroyed. Before take some actions
with a geom, check that it is not destroyed at the moment.
Tested by: nwhitehorn
MFC after: 1 week
o Detect when Boot Camp is enabled (i.e. the MBR mirrors the GPT).
o When Boot Camp is enabled, update the MBR whenever we write the GPT.
o Creation of a Boot Camp enabled GPT is not supported.
o Automatically disable Boot Camp when the GPT has been changed so that
there's either no EFI partition or no HFS+ partition.
o The first 4 partitions (by index) get mirrored in the MBR.
Requested by, discussed with and tested by: kris@pcbsd.org
MFC after: 1 week
