Commit Graph

2085 Commits

Author SHA1 Message Date
Mark Johnston
a4834289d6 Handle NULL entries in gmirror disk ds_bios arrays.
Entries may be removed and freed if an I/O error occurs during mirror
synchronization, so we cannot assume that all entries of ds_bios are
valid.

Also ensure that a synchronization BIO's array index is preserved after
a successful write.

Reported and tested by:	pho
MFC after:	2 weeks
Sponsored by:	Dell EMC Isilon
2017-04-10 17:15:59 +00:00
Allan Jude
ec5c0e5be9 Implement boot-time encryption key passing (keybuf)
This patch adds a general mechanism for providing encryption keys to the
kernel from the boot loader. This is intended to enable GELI support at
boot time, providing a better mechanism for passing keys to the kernel
than environment variables. It is designed to be extensible to other
applications, and can easily handle multiple encrypted volumes with
different keys.

This mechanism is currently used by the pending GELI EFI work.
Additionally, this mechanism can potentially be used to interface with
GRUB, opening up options for coreboot+GRUB configurations with completely
encrypted disks.

Another benefit over the existing system is that it does not require
re-deriving the user key from the password at each boot stage.

Most of this patch was written by Eric McCorkle. It was extended by
Allan Jude with a number of minor enhancements and extending the keybuf
feature into boot2.

GELI user keys are now derived once, in boot2, then passed to the loader,
which reuses the key, then passes it to the kernel, where the GELI module
destroys the keybuf after decrypting the volumes.

Submitted by:	Eric McCorkle <eric@metricspace.net> (Original Version)
Reviewed by:	oshogbo (earlier version), cem (earlier version)
MFC after:	3 weeks
Relnotes:	yes
Sponsored by:	ScaleEngine Inc.
Differential Revision:	https://reviews.freebsd.org/D9575
2017-04-01 05:05:22 +00:00
Allan Jude
39b7ca4533 sys/geom/eli: Switch bzero() to explicit_bzero() for sensitive data
In GELI, anywhere we are zeroing out possibly sensitive data, like
the metadata struct, the metadata sector (both contain the encrypted
master key), the user key, or the master key, use explicit_bzero.

Didn't touch the bzero() used to initialize structs.

Reviewed by:	delphij, oshogbo
Sponsored by:	ScaleEngine Inc.
Differential Revision:	https://reviews.freebsd.org/D9809
2017-03-31 00:07:03 +00:00
Mark Johnston
0d75d0dfbc Avoid sleeping when the mirror I/O queue is non-empty.
A request may be queued while the queue lock is dropped when the mirror is
being destroyed. The corresponding wakeup would be lost, possibly resulting
in an apparent hang of the mirror worker thread.

Tested by:	pho (part of a larger patch)
MFC after:	1 week
Sponsored by:	Dell EMC Isilon
2017-03-29 19:39:07 +00:00
Mark Johnston
c1ab409cba Remove an unneeded g_mirror_destroy_provider() call.
The worker thread will destroy the mirror provider as part of its teardown
sequence. The call made sense in the initial revision of gmirror, but
became unnecessary in r137248.

Tested by:	pho (part of a larger diff)
MFC afteR:	2 weeks
Sponsored by:	Dell EMC Isilon
2017-03-29 19:30:22 +00:00
Mark Johnston
819cd913f4 Refine r301173 a bit.
- Don't execute any of g_mirror_shutdown_post_sync() when panicking. We
  cannot safely idle the mirror or stop synchronization in that state, and
  the current attempts to do so complicate debugging of gmirror itself.
- Check for a non-NULL panicstr instead of using SCHEDULER_STOPPED(). The
  latter was added for use in the locking primitives.

Reviewed by:	mav, pjd
MFC after:	2 weeks
Sponsored by:	Dell EMC Isilon
2017-03-27 16:25:58 +00:00
Marcelo Araujo
7f5f84f08f After r315112 I broke the tests with eli, instead to pass 0, I should pass
M_NOWAIT to g_media_changed() that will call g_post_event() with this flag.

Reported by:	lwhsu, ngie and ae
2017-03-13 13:56:01 +00:00
Scott Long
d8474e52e3 Report disk flags via the sysctl tree 2017-03-13 11:09:17 +00:00
Marcelo Araujo
2ae0afa8ee Add the capability to refresh the gpart(8) label without need a reboot.
gpart(8) has functionality to change the label of an GPT partition.
This functionality works like it should, however, after a label change
the /dev/gpt/ entries remain unchanged. glabel(8) status output remains
unchanged. The change only takes effect after a reboot.

PR:		162690
Submitted by:	sub.mesa@gmail, Ben RUBSON <ben.rubson@gmail.com>, ae
Reviewed by:	allanjude, bapt, bcr
MFC after:	6 weeks.
Differential Revision:	https://reviews.freebsd.org/D9935
2017-03-12 04:15:56 +00:00
Alexander Motin
4d5832bc12 When chunking large DIOCGDELETE, do it on stripe edge.
MFC after:	2 weeks
2017-03-08 12:18:58 +00:00
Mariusz Zaborski
c27fb0b589 The kern.geom.part.auto_resize should be tunable. 2017-02-28 20:51:20 +00:00
Mariusz Zaborski
01ad653a81 Add sysctl to control auto resize of the GEOM metadata.
Reviewed by:	AllanJude
Differential Revision:	https://reviews.freebsd.org/D9603
2017-02-27 17:54:01 +00:00
Marius Strobl
4874af73c1 - Allow different slicers for different flash types to be registered
with geom_flashmap(4) and teach it about MMC for slicing enhanced
  user data area partitions. The FDT slicer still is the default for
  CFI, NAND and SPI flash on FDT-enabled platforms.
- In addition to a device_t, also pass the name of the GEOM provider
  in question to the slicers as a single device may provide more than
  provider.
- Build a geom_flashmap.ko.
- Use MODULE_VERSION() so other modules can depend on geom_flashmap(4).
- Remove redundant/superfluous GEOM routines that either do nothing
  or provide/just call default GEOM (slice) functionality.
- Trim/adjust includes

Submitted by:	jhibbits (RouterBoard bits)
Reviewed by:	jhibbits
2017-02-22 10:21:39 +00:00
Allan Jude
85c15ab853 improve PBKDF2 performance
The PBKDF2 in sys/geom/eli/pkcs5v2.c is around half the speed it could be

GELI's PBKDF2 uses a simple benchmark to determine a number of iterations
that will takes approximately 2 seconds. The security provided is actually
half what is expected, because an attacker could use the optimized
algorithm to brute force the key in half the expected time.

With this change, all newly generated GELI keys will be approximately 2x
as strong. Previously generated keys will talk half as long to calculate,
resulting in faster mounting of encrypted volumes. Users may choose to
rekey, to generate a new key with the larger default number of iterations
using the geli(8) setkey command.

Security of existing data is not compromised, as ~1 second per brute force
attempt is still a very high threshold.

PR:		202365
Original Research:	https://jbp.io/2015/08/11/pbkdf2-performance-matters/
Submitted by:	Joe Pixton <jpixton@gmail.com> (Original Version), jmg (Later Version)
Reviewed by:	ed, pjd, delphij
Approved by:	secteam, pjd (maintainer)
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D8236
2017-02-19 19:30:31 +00:00
John Baldwin
dcbe5188da Defer startup of gjournal switcher kproc.
Don't start switcher kproc until the first GEOM is created.

Reviewed by:	pjd
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D8576
2017-02-07 22:45:59 +00:00
Andrey V. Elsukov
9ef6004352 Check that primary GPT header is valid before wiping partitioning.
This allows safely destroy corrupted GPT when primary header was
rewritten by some data, that do not want to destroy.

MFC after:	1 week
2017-02-04 05:09:47 +00:00
Yoshihiro Takahashi
2b375b4edd Remove pc98 support completely.
I thank all developers and contributors for pc98.

Relnotes:	yes
2017-01-28 02:22:15 +00:00
Alexander Motin
d3fef0a092 Report disk addition errors on add or create subcommand.
MFC after:	1 week
2017-01-20 13:49:04 +00:00
Alexander Motin
17160457b4 Report random flash storage as non-rotating to GEOM_DISK.
While doing it, introduce respective constants in geom_disk.h.

MFC after:	1 week
2017-01-12 08:53:10 +00:00
Conrad Meyer
b28ea2c250 g_raid: Prevent tasters from attempting excessively large reads
Some g_raid tasters attempt metadata reads in multiples of the provider
sectorsize.  Reads larger than MAXPHYS are invalid, so detect and abort
in such situations.

Spiritually similar to r217305 / PR 147851.

PR:		214721
Sponsored by:	Dell EMC Isilon
2017-01-12 06:58:31 +00:00
Dimitry Andric
012039fd55 Fix logic error in gvinum's gv_set_sd_state()
With clang 4.0.0, I'm getting the following warnings:

    sys/geom/vinum/geom_vinum_state.c:186:7: error: logical not is only
    applied to the left hand side of this bitwise operator
    [-Werror,-Wlogical-not-parentheses]
                    if (!flags & GV_SETSTATE_FORCE)
                        ^      ~

The logical not operator should obiously be called after masking.

Reviewed by:	mav, pfg
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D9093
2017-01-08 17:56:54 +00:00
Sepherosa Ziehau
c22dceff9d build: Unbreak LINT
Sponsored by:	Microsoft
2016-12-21 01:39:11 +00:00
Konrad Witaszczyk
480f31c214 Add support for encrypted kernel crash dumps.
Changes include modifications in kernel crash dump routines, dumpon(8) and
savecore(8). A new tool called decryptcore(8) was added.

A new DIOCSKERNELDUMP I/O control was added to send a kernel crash dump
configuration in the diocskerneldump_arg structure to the kernel.
The old DIOCSKERNELDUMP I/O control was renamed to DIOCSKERNELDUMP_FREEBSD11 for
backward ABI compatibility.

dumpon(8) generates an one-time random symmetric key and encrypts it using
an RSA public key in capability mode. Currently only AES-256-CBC is supported
but EKCD was designed to implement support for other algorithms in the future.
The public key is chosen using the -k flag. The dumpon rc(8) script can do this
automatically during startup using the dumppubkey rc.conf(5) variable.  Once the
keys are calculated dumpon sends them to the kernel via DIOCSKERNELDUMP I/O
control.

When the kernel receives the DIOCSKERNELDUMP I/O control it generates a random
IV and sets up the key schedule for the specified algorithm. Each time the
kernel tries to write a crash dump to the dump device, the IV is replaced by
a SHA-256 hash of the previous value. This is intended to make a possible
differential cryptanalysis harder since it is possible to write multiple crash
dumps without reboot by repeating the following commands:
# sysctl debug.kdb.enter=1
db> call doadump(0)
db> continue
# savecore

A kernel dump key consists of an algorithm identifier, an IV and an encrypted
symmetric key. The kernel dump key size is included in a kernel dump header.
The size is an unsigned 32-bit integer and it is aligned to a block size.
The header structure has 512 bytes to match the block size so it was required to
make a panic string 4 bytes shorter to add a new field to the header structure.
If the kernel dump key size in the header is nonzero it is assumed that the
kernel dump key is placed after the first header on the dump device and the core
dump is encrypted.

Separate functions were implemented to write the kernel dump header and the
kernel dump key as they need to be unencrypted. The dump_write function encrypts
data if the kernel was compiled with the EKCD option. Encrypted kernel textdumps
are not supported due to the way they are constructed which makes it impossible
to use the CBC mode for encryption. It should be also noted that textdumps don't
contain sensitive data by design as a user decides what information should be
dumped.

savecore(8) writes the kernel dump key to a key.# file if its size in the header
is nonzero. # is the number of the current core dump.

decryptcore(8) decrypts the core dump using a private RSA key and the kernel
dump key. This is performed by a child process in capability mode.
If the decryption was not successful the parent process removes a partially
decrypted core dump.

Description on how to encrypt crash dumps was added to the decryptcore(8),
dumpon(8), rc.conf(5) and savecore(8) manual pages.

EKCD was tested on amd64 using bhyve and i386, mipsel and sparc64 using QEMU.
The feature still has to be tested on arm and arm64 as it wasn't possible to run
FreeBSD due to the problems with QEMU emulation and lack of hardware.

Designed by:	def, pjd
Reviewed by:	cem, oshogbo, pjd
Partial review:	delphij, emaste, jhb, kib
Approved by:	pjd (mentor)
Differential Revision:	https://reviews.freebsd.org/D4712
2016-12-10 16:20:39 +00:00
Alexander Motin
b6fe583c55 Add gmirror create subcommand, alike to gstripe, gconcat, etc.
It is quite specific mode of operation without storing on-disk metadata.
It can be useful in some cases in combination with some external control
tools handling mirror creation and disks hot-plug.

MFC after:	2 weeks
Sponsored by:	iXsystems, Inc.
2016-11-30 09:27:08 +00:00
Alexander Motin
dc399583ba Use providergone method to cover race between destroy and g_access().
Reviewed by:	markj
MFC after:	2 weeks
Sponsored by:	iXsystems, Inc.
2016-11-13 03:56:26 +00:00
Alexander Motin
80f0a89c62 Do not report error on close even if we have no paths left.
MFC after:	 2 weeks
2016-11-12 18:57:38 +00:00
Bryan Drewery
28323add09 Fix improper use of "its".
Sponsored by:	Dell EMC Isilon
2016-11-08 23:59:41 +00:00
Conrad Meyer
8532d381a9 Add BUF_TRACKING and FULL_BUF_TRACKING buffer debugging
Upstream the BUF_TRACKING and FULL_BUF_TRACKING buffer debugging code.
This can be handy in tracking down what code touched hung bios and bufs
last. The full history is especially useful, but adds enough bloat that
it shouldn't be enabled in release builds.

Function names (or arbitrary string constants) are tracked in a
fixed-size ring in bufs. Bios gain a pointer to the upper buf for
tracking. SCSI CCBs gain a pointer to the upper bio for tracking.

Reviewed by:	markj
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D8366
2016-10-31 23:09:52 +00:00
Ruslan Bukin
ae8b1f90fe Fix alignment issues on MIPS: align the pointers properly.
All the 5520 GEOM_ELI tests passed successfully on MIPS64EB.

Sponsored by:	DARPA, AFRL
Sponsored by:	HEIF5
Differential Revision:	https://reviews.freebsd.org/D7905
2016-10-31 16:55:14 +00:00
Mark Johnston
5c2ac5cf2a gmirror: Add a subroutine to free synchronization BIOs.
This addresses a memory leak that occurs upon an I/O error during a mirror
synchronization.

MFC after:	2 weeks
Sponsored by:	Dell EMC Isilon
2016-10-20 23:08:40 +00:00
Mark Johnston
b450976dc2 gmirror: Release pending regular requests when synchronization stops.
Normally gmirror allows colliding requests to proceed whenever a
synchronization request completes and advances to the next offset. However
if an I/O request collides with one of the final g_mirror_syncreqs, nothing
releases it once synchronization completes, resulting in an apparent I/O
hang. The same problem can occur if synchronization is aborted by an
I/O error. Therefore, be sure to requeue pending requests when
mirror synchronization is stopped for any reason.

While here, remove some dead code from g_mirror_regular_release().

MFC after:	2 weeks
Sponsored by:	Dell EMC Isilon
2016-10-20 23:02:30 +00:00
Alexander Motin
5a236b0ef9 Fix possible geom destruction before final provider close.
Introduce internal counter to track opens.  Using provider's counters is
not very successfull after calling g_wither_provider().

MFC after:	2 weeks
Sponsored by:	iXsystems, Inc.
2016-10-06 15:20:05 +00:00
Mark Johnston
4dea20be45 gmirror: Write an updated syncid before queuing writes.
When a syncid bump is pending, any write to the mirror results in the
updated syncid being written to each component's metadata block. However,
the update was only being performed after the writes to the mirror
componenents were queued. Instead, synchronously update the metadata block
first.

MFC after:	3 weeks
Sponsored by:	Dell EMC Isilon
2016-10-06 00:13:55 +00:00
Mark Johnston
903618cd65 gmirror: Bump the syncid if broken disks are found during startup.
Consider a mirror with two components, m1 and m2. Suppose a hardware error
results in the removal of m2, with m1's genid bumped. Suppose further that
a replacement mirror component m3 is created and synchronized, after which
the system is shut down uncleanly. During a subsequent bootup, if gmirror
tastes m1 and m2 first, m2 will be removed from the mirror because it is
broken, but the mirror will be started without bumping the syncid on m1
because all elements of the mirror are accounted for. Then m3 will be
added to the already-running mirror with the same syncid as m1, so the
components will not be synchronized despite the unclean shutdown.

Handle this scenario by bumping the syncid of healthy components if any
broken mirrors are discovered during mirror startup.

MFC after:	3 weeks
Sponsored by:	Dell EMC Isilon
2016-10-06 00:05:45 +00:00
Mark Johnston
fff048e4bc gmirror: Use bool instead of boolean_t.
MFC after:	1 week
Sponsored by:	Dell EMC Isilon
2016-10-05 23:55:01 +00:00
Adrian Chadd
85ab1aeccf [geom_redboot] Extend geom_redboot to handle non-zero fis offset.
Submitted by:	Mori Hiroki <yamori813@yahoo.co.jp>
Differential Revision:	https://reviews.freebsd.org/D7237
2016-10-04 16:35:38 +00:00
Alexander Motin
8b64f3ca6c Use g_wither_provider() where applicable.
It is just a helper function combining G_PF_WITHER setting with
g_orphan_provider().
2016-09-23 21:29:40 +00:00
Edward Tomasz Napierala
0c4440c3aa Follow up r305988 by removing g_bio_run_task and related code.
The g_io_schedule_up() gets its "if" condition swapped to make
it more similar to g_io_schedule_down().

Suggested by:	mav@
Reviewed by:	mav@
MFC after:	1 month
2016-09-20 09:18:33 +00:00
Edward Tomasz Napierala
bbdd6614bd Remove unused bio_taskqueue().
MFC after:	1 month
2016-09-19 17:46:15 +00:00
Mark Johnston
4bfb585351 Don't treat an error from g_mirror_clear_metadata() as fatal.
Such errors can occur as the result of a write error or because the disk
backing the mirror element was removed. They result in a generation ID bump
on all active elements of the mirror, so we can safely disconnect the mirror
component rather than destroy it.

MFC after:	2 weeks
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D7750
2016-09-06 23:42:59 +00:00
Mark Johnston
40c5032d32 Add some fail points to gmirror.
These are useful for testing changes to I/O error handling, and for
reproducing existing bugs in a controlled manner. The fail points are

    g_mirror_regular_request_read
    g_mirror_regular_request_write
    g_mirror_sync_request_read
    g_mirror_sync_request_write
    g_mirror_metadata_write

They all effectively allow one to inject an error value into the bio_error
field of a corresponding BIO request as it is being completed.

MFC after:	2 weeks
Sponsored by:	EMC / Isilon Storage Division
2016-09-06 23:35:48 +00:00
Andrey V. Elsukov
0428336393 Do not invoke resize event if initial disk size is zero. Some disks
report the size only after first opening.  And due to the events are
asynchronous, some consumers can receive this event too late and
this confuses them. This partially restores previous behaviour, and
at the same time this should fix the problem, when already opened
provider loses resize event.

PR:		211028
MFC after:	3 weeks
2016-08-01 20:54:54 +00:00
Andrey V. Elsukov
1f353a2315 Do not invoke resize method if geom is being withered.
PR:		211028
MFC after:	2 weeks
2016-07-25 09:12:08 +00:00
Andrey V. Elsukov
f1ff88cf8c Use g_resize_provider() to change the size of GEOM_DISK provider,
when it is being opened. This should fix the possible loss of a resize
event when disk capacity changed.

PR:		211028
Reported by:	Dexuan Cui <decui at microsoft dot com>
MFC after:	3 weeks
2016-07-19 05:36:21 +00:00
Maxim Sobolev
55f9588af4 Relax checking if the privider size matches size recorded in the
superblock, allowing provider to be bit bigger, i.e. have some
extra padding after the FS image. That in some cases might be
a side-effect of using CLOOP format which enforces certain block
size and trying to compress image that is not exactly the number
of those blocks in size. The UFS itself does not have any issues
mounting such padded file systems, so it's what GEOM_LABEL should
do.

Submitted by:	@mizhka_gmail.com
Differential Revision:	https://reviews.freebsd.org/D6208
2016-07-18 05:00:01 +00:00
Mark Johnston
7d31c3939a Move some gmirror metadata update messages to a higher debug level.
These can be printed quite frequently from a mostly-idle mirror, cluttering
the console.

MFC after:	1 week
2016-07-14 00:40:24 +00:00
Maxim Sobolev
74ba4047a3 1.Improve handling around last compressed block of the file, which is
necessary because CLOOP format lacks explicit EOF or length, so that
  in the presence of padding or when the CLOOP is put onto a larger
  partition upper level provider size may be larger. Bound amount
  of extra data that we might touch to the max length of the compressed
  block and detect zero-padding in the last cluster, which when
  sector is all-zero might cause us to emit bogus I/O error after
  decompression of that fails. To not make code any more complicated
  that it needs to be deal with it in lazy-manner, i.e. when we
  first access that specific cluster.

  This change also fixes stupid mistake in the LZMA code, inherited
  from geom_lzma, which does not share length of the output buffer
  buffer with the decompression routine, so that in the presence
  of corrupted or purposedly tailored data may easily cause heap
  overflow and kernel memory corruption.

  Beef up validation of the CLOOP TOC by checking that lengths of
  all but the last compressed clusters match upper limit set by
  the decompressor and improve some error diagnostic output while
  I am here.

2.Add kern.geom.uzip.attach_to tunable to artifically limit
  attaching uzip to certain devices in the dev tree only.

    For example the following only makes us attaching to the
    GPT labels:

    kern.geom.uzip.attach_to="gpt/*"

3.Add kern.geom.uzip.noattach_to, which does opposite to the (2)
  above, i.e. prevents geom_uzip from tasting / attaching to
  providers matching some pattern. By default we don't attach
  to our own kind, i.e. kern.geom.uzip.noattach_to="*.uzip".
  It saves us quite some CPU cycles, esp on low-end embedded
  systems.

Approved by:	re (gjb)
Differential Revision:	https://reviews.freebsd.org/D7013
2016-06-29 18:19:05 +00:00
Kenneth D. Merry
a02e196edd Switch geom_disk over to using a pool mutex.
The GEOM disk d_mtx is only acquired on disk creation and destruction.
It is a good candidate for replacement with a pool mutex.  This eliminates
the mutex initialization and teardown and the mutex and name variables
themselves from struct disk.

sys/geom/geom_disk.h:
	Take d_mtx and d_mtx_name out of struct disk.

sys/geom/geom_disk.c:
	Use mtx_pool_lock() and mtx_pool_unlock() to guard the disk
	initialization state instead of a dedicated mutex.

	This allows removing the initialization and destruction of
	d_mtx.

sys/sys/param.h:
	Bump __FreeBSD_version to 1100119 for the change to struct disk.

Suggested by:	jhb
Sponsored by:	Spectra Logic
Approved by:	re (gjb)
2016-06-23 20:05:59 +00:00
Mark Johnston
be20fc2e90 Do not complete pending gmirror BIOs when tearing down the provider.
This will result in lock recursion and is more generally incorrect since
the completion handlers will just reinsert the BIOs into the queue we're
trying to drain.

Reviewed by:	imp, ngie
Approved by:	re (gjb)
MFC after:	3 weeks
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D6908
2016-06-22 21:00:28 +00:00
Kenneth D. Merry
e5616d65d0 Fix a bug that caused da(4) peripheral drivers to not fully go away
after the underlying device went away.

The problem was that callers who queue the GEOM resize provider
event didn't check to make sure that the provider had not been
withered.  For the other equivalent case, g_new_provider_event(),
the code checks to see whether the provider has been withered
before queueing a g_new_provider_event() to the event thread.

In some cases, a resize provider event would come through after
the provider had been withered and all of the existing consumers
had been orphaned.  When the resize event triggered a taste of
the provider, that would attach a new consumer to the now
withered provider.  The wither washer (g_wither_washer() would
never be able to completely tear down the GEOM because of the
consumers that were hanging around.

The solution was to check the G_PF_WITHER provider flag before
queueing the g_resize_provider_event(), and add an assert to
g_resize_provider_event() to insure that it isn't called on a
withered provider.

sys/geom/geom_subr.c:
	In g_resize_provider(), don't try to continue if the
	G_PF_WITHER flag is set.

	In g_resize_provider_event(), add an assert that the
	G_PF_WITHER flag is not set.

	In g_access(), if a provider has an error, print out the
	name of the provider with the error.

Sponsored by:	Spectra Logic
Approved by:	re (marius)
MFC after:	3 days
2016-06-22 14:39:13 +00:00