MFC r314908: When chunking large DIOCGDELETE, do it on stripe edge.

MFC r300881, r302058 (by asomers):
Avoid issuing spa config updates for physical path when not necessary

ZFS's configuration needs to be updated whenever the physical path for a
device changes, but not when a new device is introduced. This is because new
devices necessarily cause config updates, but only if they are actually
accepted into the pool.

sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_geom.c
Split vdev_geom_set_physpath out of vdev_geom_attrchanged. When
setting the vdev's physical path, only request a config update if
the physical path has changed. Don't request it when opening a
device for the first time, because the config sync will happen
anyway upstack.

sys/geom/geom_dev.c
Split g_dev_set_physpath and g_dev_set_media out of
g_dev_attrchanged

MFC r291004:

Fix early kernel dump via dumpdev env

Sponsored by: Multiplay

MFC r288153:

Use kenv 'dumpdev' in the same way as etc/rc.d/dumpon

Sponsored by: Multiplay

MFC r274366:

Add missing privilege check when setting the dump device.

Approved by: pjd, secteam (both no objections)
Sponsored by: Multiplay

MFC r286283:

Fix panic triggered by code like this:
open("/dev/md0", O_EXEC);

Sponsored by: The FreeBSD Foundation

MFC r286237:

Fix panic that would happen on forcibly unmounting devfs (note that
as it is now, devfs ignores MNT_FORCE anyway, so it needs to be modified
to trigger the panic) with consumers still opened.

Note that this still results in a leak of r/w/e counters. It seems
to be harmless, though. If anyone knows a better way to approach
this - please tell.

Sponsored by: The FreeBSD Foundation

MFC 281310, 287567:

r287567 | imp | 2015-09-08 11:47:56 -0600 (Tue, 08 Sep 2015) | 16 lines

Mark the swap pager as direct dispatch compatible.

r281310 | mav | 2015-04-09 07:09:05 -0600 (Thu, 09 Apr 2015) | 4 lines

Remove sleeps from geom_up thread on device destruction.

MFC r277170:

Add devd(8) notifications for creation and destruction of GEOM devices.

Sponsored by: The FreeBSD Foundation

MFC r274154, r274163:
Add to CTL support for logical block provisioning threshold notifications.

For ZVOL-backed LUNs this allows to inform initiators if storage's used or
available spaces get above/below the configured thresholds.

Sponsored by: iXsystems, Inc.

MFC r272746:
Add an ability to set dumpdev via loader(8) tunable.

MFC r272747:
Revert r156046. We support setting dumpdev via loader tunable again.
Also change default disk name to ada.

MFC Alexander Motin's GEOM direct dispatch work:

r256603:
Introduce new function devstat_end_transaction_bio_bt(), adding new argument
to specify present time. Use this function to move binuptime() out of lock,
substantially reducing lock congestion when slow timecounter is used.

r256606:
Move g_io_deliver() out of the lock, as required for direct dispatch.
Move g_destroy_bio() out too to reduce lock scope even more.

r256607:
Fix passing uninitialized bio_resid argument to g_trace().

r256610:
Add unmapped I/O support to GEOM RAID.

r256830:
Restore BIO_UNMAPPED and BIO_TRANSIENT_MAPPING in biodonne() when unmapping
temporary mapped buffer. That fixes double unmap if biodone() called twice
for the same BIO (but with different done methods).

r256880:
Merge GEOM direct dispatch changes from the projects/camlock branch.

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.

r259247:
Fix bug introduced at r256607. We have to recalculate bp_resid here since
sizes of original and completed requests may differ due to end of media.

Testing of the stable/10 merge was done by Netflix, but all of the credit
goes to Alexander and iX Systems.

Submitted by: mav
Sponsored by: iX Systems

MFC 281310, 287567:

r287567 | imp | 2015-09-08 11:47:56 -0600 (Tue, 08 Sep 2015) | 16 lines

Mark the swap pager as direct dispatch compatible.

r281310 | mav | 2015-04-09 07:09:05 -0600 (Thu, 09 Apr 2015) | 4 lines

Remove sleeps from geom_up thread on device destruction.

MFC r277170:

Add devd(8) notifications for creation and destruction of GEOM devices.

Sponsored by: The FreeBSD Foundation

MFC r274154, r274163:
Add to CTL support for logical block provisioning threshold notifications.

For ZVOL-backed LUNs this allows to inform initiators if storage's used or
available spaces get above/below the configured thresholds.

Sponsored by: iXsystems, Inc.

MFC r272746:
Add an ability to set dumpdev via loader(8) tunable.

MFC r272747:
Revert r156046. We support setting dumpdev via loader tunable again.
Also change default disk name to ada.

MFC Alexander Motin's GEOM direct dispatch work:

r256603:
Introduce new function devstat_end_transaction_bio_bt(), adding new argument
to specify present time. Use this function to move binuptime() out of lock,
substantially reducing lock congestion when slow timecounter is used.

r256606:
Move g_io_deliver() out of the lock, as required for direct dispatch.
Move g_destroy_bio() out too to reduce lock scope even more.

r256607:
Fix passing uninitialized bio_resid argument to g_trace().

r256610:
Add unmapped I/O support to GEOM RAID.

r256830:
Restore BIO_UNMAPPED and BIO_TRANSIENT_MAPPING in biodonne() when unmapping
temporary mapped buffer. That fixes double unmap if biodone() called twice
for the same BIO (but with different done methods).

r256880:
Merge GEOM direct dispatch changes from the projects/camlock branch.

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.

r259247:
Fix bug introduced at r256607. We have to recalculate bp_resid here since
sizes of original and completed requests may differ due to end of media.

Testing of the stable/10 merge was done by Netflix, but all of the credit
goes to Alexander and iX Systems.

Submitted by: mav
Sponsored by: iX Systems