4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
26 * Virtual Device Labels
27 * ---------------------
29 * The vdev label serves several distinct purposes:
31 * 1. Uniquely identify this device as part of a ZFS pool and confirm its
32 * identity within the pool.
34 * 2. Verify that all the devices given in a configuration are present
37 * 3. Determine the uberblock for the pool.
39 * 4. In case of an import operation, determine the configuration of the
40 * toplevel vdev of which it is a part.
42 * 5. If an import operation cannot find all the devices in the pool,
43 * provide enough information to the administrator to determine which
44 * devices are missing.
46 * It is important to note that while the kernel is responsible for writing the
47 * label, it only consumes the information in the first three cases. The
48 * latter information is only consumed in userland when determining the
49 * configuration to import a pool.
55 * Before describing the contents of the label, it's important to understand how
56 * the labels are written and updated with respect to the uberblock.
58 * When the pool configuration is altered, either because it was newly created
59 * or a device was added, we want to update all the labels such that we can deal
60 * with fatal failure at any point. To this end, each disk has two labels which
61 * are updated before and after the uberblock is synced. Assuming we have
62 * labels and an uberblock with the following transaction groups:
65 * +------+ +------+ +------+
67 * | t10 | | t10 | | t10 |
69 * +------+ +------+ +------+
71 * In this stable state, the labels and the uberblock were all updated within
72 * the same transaction group (10). Each label is mirrored and checksummed, so
73 * that we can detect when we fail partway through writing the label.
75 * In order to identify which labels are valid, the labels are written in the
78 * 1. For each vdev, update 'L1' to the new label
79 * 2. Update the uberblock
80 * 3. For each vdev, update 'L2' to the new label
82 * Given arbitrary failure, we can determine the correct label to use based on
83 * the transaction group. If we fail after updating L1 but before updating the
84 * UB, we will notice that L1's transaction group is greater than the uberblock,
85 * so L2 must be valid. If we fail after writing the uberblock but before
86 * writing L2, we will notice that L2's transaction group is less than L1, and
87 * therefore L1 is valid.
89 * Another added complexity is that not every label is updated when the config
90 * is synced. If we add a single device, we do not want to have to re-write
91 * every label for every device in the pool. This means that both L1 and L2 may
92 * be older than the pool uberblock, because the necessary information is stored
99 * The vdev label consists of two distinct parts, and is wrapped within the
100 * vdev_label_t structure. The label includes 8k of padding to permit legacy
101 * VTOC disk labels, but is otherwise ignored.
103 * The first half of the label is a packed nvlist which contains pool wide
104 * properties, per-vdev properties, and configuration information. It is
105 * described in more detail below.
107 * The latter half of the label consists of a redundant array of uberblocks.
108 * These uberblocks are updated whenever a transaction group is committed,
109 * or when the configuration is updated. When a pool is loaded, we scan each
110 * vdev for the 'best' uberblock.
113 * Configuration Information
114 * -------------------------
116 * The nvlist describing the pool and vdev contains the following elements:
118 * version ZFS on-disk version
121 * txg Transaction group in which this label was written
122 * pool_guid Unique identifier for this pool
123 * vdev_tree An nvlist describing vdev tree.
125 * Each leaf device label also contains the following:
127 * top_guid Unique ID for top-level vdev in which this is contained
128 * guid Unique ID for the leaf vdev
130 * The 'vs' configuration follows the format described in 'spa_config.c'.
133 #include <sys/zfs_context.h>
135 #include <sys/spa_impl.h>
138 #include <sys/vdev.h>
139 #include <sys/vdev_impl.h>
140 #include <sys/uberblock_impl.h>
141 #include <sys/metaslab.h>
143 #include <sys/dsl_scan.h>
144 #include <sys/fs/zfs.h>
147 * Basic routines to read and write from a vdev label.
148 * Used throughout the rest of this file.
151 vdev_label_offset(uint64_t psize
, int l
, uint64_t offset
)
153 ASSERT(offset
< sizeof (vdev_label_t
));
154 ASSERT(P2PHASE_TYPED(psize
, sizeof (vdev_label_t
), uint64_t) == 0);
156 return (offset
+ l
* sizeof (vdev_label_t
) + (l
< VDEV_LABELS
/ 2 ?
157 0 : psize
- VDEV_LABELS
* sizeof (vdev_label_t
)));
161 * Returns back the vdev label associated with the passed in offset.
164 vdev_label_number(uint64_t psize
, uint64_t offset
)
168 if (offset
>= psize
- VDEV_LABEL_END_SIZE
) {
169 offset
-= psize
- VDEV_LABEL_END_SIZE
;
170 offset
+= (VDEV_LABELS
/ 2) * sizeof (vdev_label_t
);
172 l
= offset
/ sizeof (vdev_label_t
);
173 return (l
< VDEV_LABELS
? l
: -1);
177 vdev_label_read(zio_t
*zio
, vdev_t
*vd
, int l
, void *buf
, uint64_t offset
,
178 uint64_t size
, zio_done_func_t
*done
, void *private, int flags
)
180 ASSERT(spa_config_held(zio
->io_spa
, SCL_STATE_ALL
, RW_WRITER
) ==
182 ASSERT(flags
& ZIO_FLAG_CONFIG_WRITER
);
184 zio_nowait(zio_read_phys(zio
, vd
,
185 vdev_label_offset(vd
->vdev_psize
, l
, offset
),
186 size
, buf
, ZIO_CHECKSUM_LABEL
, done
, private,
187 ZIO_PRIORITY_SYNC_READ
, flags
, B_TRUE
));
191 vdev_label_write(zio_t
*zio
, vdev_t
*vd
, int l
, void *buf
, uint64_t offset
,
192 uint64_t size
, zio_done_func_t
*done
, void *private, int flags
)
194 ASSERT(spa_config_held(zio
->io_spa
, SCL_ALL
, RW_WRITER
) == SCL_ALL
||
195 (spa_config_held(zio
->io_spa
, SCL_CONFIG
| SCL_STATE
, RW_READER
) ==
196 (SCL_CONFIG
| SCL_STATE
) &&
197 dsl_pool_sync_context(spa_get_dsl(zio
->io_spa
))));
198 ASSERT(flags
& ZIO_FLAG_CONFIG_WRITER
);
200 zio_nowait(zio_write_phys(zio
, vd
,
201 vdev_label_offset(vd
->vdev_psize
, l
, offset
),
202 size
, buf
, ZIO_CHECKSUM_LABEL
, done
, private,
203 ZIO_PRIORITY_SYNC_WRITE
, flags
, B_TRUE
));
207 * Generate the nvlist representing this vdev's config.
210 vdev_config_generate(spa_t
*spa
, vdev_t
*vd
, boolean_t getstats
,
211 vdev_config_flag_t flags
)
215 VERIFY(nvlist_alloc(&nv
, NV_UNIQUE_NAME
, KM_SLEEP
) == 0);
217 VERIFY(nvlist_add_string(nv
, ZPOOL_CONFIG_TYPE
,
218 vd
->vdev_ops
->vdev_op_type
) == 0);
219 if (!(flags
& (VDEV_CONFIG_SPARE
| VDEV_CONFIG_L2CACHE
)))
220 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_ID
, vd
->vdev_id
)
222 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_GUID
, vd
->vdev_guid
) == 0);
224 if (vd
->vdev_path
!= NULL
)
225 VERIFY(nvlist_add_string(nv
, ZPOOL_CONFIG_PATH
,
226 vd
->vdev_path
) == 0);
228 if (vd
->vdev_devid
!= NULL
)
229 VERIFY(nvlist_add_string(nv
, ZPOOL_CONFIG_DEVID
,
230 vd
->vdev_devid
) == 0);
232 if (vd
->vdev_physpath
!= NULL
)
233 VERIFY(nvlist_add_string(nv
, ZPOOL_CONFIG_PHYS_PATH
,
234 vd
->vdev_physpath
) == 0);
236 if (vd
->vdev_fru
!= NULL
)
237 VERIFY(nvlist_add_string(nv
, ZPOOL_CONFIG_FRU
,
240 if (vd
->vdev_nparity
!= 0) {
241 ASSERT(strcmp(vd
->vdev_ops
->vdev_op_type
,
242 VDEV_TYPE_RAIDZ
) == 0);
245 * Make sure someone hasn't managed to sneak a fancy new vdev
246 * into a crufty old storage pool.
248 ASSERT(vd
->vdev_nparity
== 1 ||
249 (vd
->vdev_nparity
<= 2 &&
250 spa_version(spa
) >= SPA_VERSION_RAIDZ2
) ||
251 (vd
->vdev_nparity
<= 3 &&
252 spa_version(spa
) >= SPA_VERSION_RAIDZ3
));
255 * Note that we'll add the nparity tag even on storage pools
256 * that only support a single parity device -- older software
257 * will just ignore it.
259 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_NPARITY
,
260 vd
->vdev_nparity
) == 0);
263 if (vd
->vdev_wholedisk
!= -1ULL)
264 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_WHOLE_DISK
,
265 vd
->vdev_wholedisk
) == 0);
267 if (vd
->vdev_not_present
)
268 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_NOT_PRESENT
, 1) == 0);
270 if (vd
->vdev_isspare
)
271 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_IS_SPARE
, 1) == 0);
273 if (!(flags
& (VDEV_CONFIG_SPARE
| VDEV_CONFIG_L2CACHE
)) &&
274 vd
== vd
->vdev_top
) {
275 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_METASLAB_ARRAY
,
276 vd
->vdev_ms_array
) == 0);
277 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_METASLAB_SHIFT
,
278 vd
->vdev_ms_shift
) == 0);
279 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_ASHIFT
,
280 vd
->vdev_ashift
) == 0);
281 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_ASIZE
,
282 vd
->vdev_asize
) == 0);
283 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_IS_LOG
,
284 vd
->vdev_islog
) == 0);
285 if (vd
->vdev_removing
)
286 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_REMOVING
,
287 vd
->vdev_removing
) == 0);
290 if (vd
->vdev_dtl_smo
.smo_object
!= 0)
291 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_DTL
,
292 vd
->vdev_dtl_smo
.smo_object
) == 0);
295 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_CREATE_TXG
,
296 vd
->vdev_crtxg
) == 0);
302 vdev_get_stats(vd
, &vs
);
303 VERIFY(nvlist_add_uint64_array(nv
, ZPOOL_CONFIG_VDEV_STATS
,
304 (uint64_t *)&vs
, sizeof (vs
) / sizeof (uint64_t)) == 0);
306 /* provide either current or previous scan information */
307 if (spa_scan_get_stats(spa
, &ps
) == 0) {
308 VERIFY(nvlist_add_uint64_array(nv
,
309 ZPOOL_CONFIG_SCAN_STATS
, (uint64_t *)&ps
,
310 sizeof (pool_scan_stat_t
) / sizeof (uint64_t))
315 if (!vd
->vdev_ops
->vdev_op_leaf
) {
319 ASSERT(!vd
->vdev_ishole
);
321 child
= kmem_alloc(vd
->vdev_children
* sizeof (nvlist_t
*),
324 for (c
= 0, idx
= 0; c
< vd
->vdev_children
; c
++) {
325 vdev_t
*cvd
= vd
->vdev_child
[c
];
328 * If we're generating an nvlist of removing
329 * vdevs then skip over any device which is
332 if ((flags
& VDEV_CONFIG_REMOVING
) &&
336 child
[idx
++] = vdev_config_generate(spa
, cvd
,
341 VERIFY(nvlist_add_nvlist_array(nv
,
342 ZPOOL_CONFIG_CHILDREN
, child
, idx
) == 0);
345 for (c
= 0; c
< idx
; c
++)
346 nvlist_free(child
[c
]);
348 kmem_free(child
, vd
->vdev_children
* sizeof (nvlist_t
*));
351 const char *aux
= NULL
;
353 if (vd
->vdev_offline
&& !vd
->vdev_tmpoffline
)
354 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_OFFLINE
,
356 if (vd
->vdev_faulted
)
357 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_FAULTED
,
359 if (vd
->vdev_degraded
)
360 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_DEGRADED
,
362 if (vd
->vdev_removed
)
363 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_REMOVED
,
365 if (vd
->vdev_unspare
)
366 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_UNSPARE
,
369 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_IS_HOLE
,
372 switch (vd
->vdev_stat
.vs_aux
) {
373 case VDEV_AUX_ERR_EXCEEDED
:
374 aux
= "err_exceeded";
377 case VDEV_AUX_EXTERNAL
:
383 VERIFY(nvlist_add_string(nv
, ZPOOL_CONFIG_AUX_STATE
,
386 if (vd
->vdev_splitting
&& vd
->vdev_orig_guid
!= 0LL) {
387 VERIFY(nvlist_add_uint64(nv
, ZPOOL_CONFIG_ORIG_GUID
,
388 vd
->vdev_orig_guid
) == 0);
396 * Generate a view of the top-level vdevs. If we currently have holes
397 * in the namespace, then generate an array which contains a list of holey
398 * vdevs. Additionally, add the number of top-level children that currently
402 vdev_top_config_generate(spa_t
*spa
, nvlist_t
*config
)
404 vdev_t
*rvd
= spa
->spa_root_vdev
;
408 array
= kmem_alloc(rvd
->vdev_children
* sizeof (uint64_t), KM_SLEEP
);
410 for (c
= 0, idx
= 0; c
< rvd
->vdev_children
; c
++) {
411 vdev_t
*tvd
= rvd
->vdev_child
[c
];
413 if (tvd
->vdev_ishole
)
418 VERIFY(nvlist_add_uint64_array(config
, ZPOOL_CONFIG_HOLE_ARRAY
,
422 VERIFY(nvlist_add_uint64(config
, ZPOOL_CONFIG_VDEV_CHILDREN
,
423 rvd
->vdev_children
) == 0);
425 kmem_free(array
, rvd
->vdev_children
* sizeof (uint64_t));
429 vdev_label_read_config(vdev_t
*vd
)
431 spa_t
*spa
= vd
->vdev_spa
;
432 nvlist_t
*config
= NULL
;
435 int flags
= ZIO_FLAG_CONFIG_WRITER
| ZIO_FLAG_CANFAIL
|
436 ZIO_FLAG_SPECULATIVE
;
438 ASSERT(spa_config_held(spa
, SCL_STATE_ALL
, RW_WRITER
) == SCL_STATE_ALL
);
440 if (!vdev_readable(vd
))
443 vp
= zio_buf_alloc(sizeof (vdev_phys_t
));
446 for (int l
= 0; l
< VDEV_LABELS
; l
++) {
448 zio
= zio_root(spa
, NULL
, NULL
, flags
);
450 vdev_label_read(zio
, vd
, l
, vp
,
451 offsetof(vdev_label_t
, vl_vdev_phys
),
452 sizeof (vdev_phys_t
), NULL
, NULL
, flags
);
454 if (zio_wait(zio
) == 0 &&
455 nvlist_unpack(vp
->vp_nvlist
, sizeof (vp
->vp_nvlist
),
459 if (config
!= NULL
) {
465 if (config
== NULL
&& !(flags
& ZIO_FLAG_TRYHARD
)) {
466 flags
|= ZIO_FLAG_TRYHARD
;
470 zio_buf_free(vp
, sizeof (vdev_phys_t
));
476 * Determine if a device is in use. The 'spare_guid' parameter will be filled
477 * in with the device guid if this spare is active elsewhere on the system.
480 vdev_inuse(vdev_t
*vd
, uint64_t crtxg
, vdev_labeltype_t reason
,
481 uint64_t *spare_guid
, uint64_t *l2cache_guid
)
483 spa_t
*spa
= vd
->vdev_spa
;
484 uint64_t state
, pool_guid
, device_guid
, txg
, spare_pool
;
491 *l2cache_guid
= 0ULL;
494 * Read the label, if any, and perform some basic sanity checks.
496 if ((label
= vdev_label_read_config(vd
)) == NULL
)
499 (void) nvlist_lookup_uint64(label
, ZPOOL_CONFIG_CREATE_TXG
,
502 if (nvlist_lookup_uint64(label
, ZPOOL_CONFIG_POOL_STATE
,
504 nvlist_lookup_uint64(label
, ZPOOL_CONFIG_GUID
,
505 &device_guid
) != 0) {
510 if (state
!= POOL_STATE_SPARE
&& state
!= POOL_STATE_L2CACHE
&&
511 (nvlist_lookup_uint64(label
, ZPOOL_CONFIG_POOL_GUID
,
513 nvlist_lookup_uint64(label
, ZPOOL_CONFIG_POOL_TXG
,
522 * Check to see if this device indeed belongs to the pool it claims to
523 * be a part of. The only way this is allowed is if the device is a hot
524 * spare (which we check for later on).
526 if (state
!= POOL_STATE_SPARE
&& state
!= POOL_STATE_L2CACHE
&&
527 !spa_guid_exists(pool_guid
, device_guid
) &&
528 !spa_spare_exists(device_guid
, NULL
, NULL
) &&
529 !spa_l2cache_exists(device_guid
, NULL
))
533 * If the transaction group is zero, then this an initialized (but
534 * unused) label. This is only an error if the create transaction
535 * on-disk is the same as the one we're using now, in which case the
536 * user has attempted to add the same vdev multiple times in the same
539 if (state
!= POOL_STATE_SPARE
&& state
!= POOL_STATE_L2CACHE
&&
540 txg
== 0 && vdtxg
== crtxg
)
544 * Check to see if this is a spare device. We do an explicit check for
545 * spa_has_spare() here because it may be on our pending list of spares
546 * to add. We also check if it is an l2cache device.
548 if (spa_spare_exists(device_guid
, &spare_pool
, NULL
) ||
549 spa_has_spare(spa
, device_guid
)) {
551 *spare_guid
= device_guid
;
554 case VDEV_LABEL_CREATE
:
555 case VDEV_LABEL_L2CACHE
:
558 case VDEV_LABEL_REPLACE
:
559 return (!spa_has_spare(spa
, device_guid
) ||
562 case VDEV_LABEL_SPARE
:
563 return (spa_has_spare(spa
, device_guid
));
568 * Check to see if this is an l2cache device.
570 if (spa_l2cache_exists(device_guid
, NULL
))
574 * If the device is marked ACTIVE, then this device is in use by another
575 * pool on the system.
577 return (state
== POOL_STATE_ACTIVE
);
581 * Initialize a vdev label. We check to make sure each leaf device is not in
582 * use, and writable. We put down an initial label which we will later
583 * overwrite with a complete label. Note that it's important to do this
584 * sequentially, not in parallel, so that we catch cases of multiple use of the
585 * same leaf vdev in the vdev we're creating -- e.g. mirroring a disk with
589 vdev_label_init(vdev_t
*vd
, uint64_t crtxg
, vdev_labeltype_t reason
)
591 spa_t
*spa
= vd
->vdev_spa
;
600 uint64_t spare_guid
, l2cache_guid
;
601 int flags
= ZIO_FLAG_CONFIG_WRITER
| ZIO_FLAG_CANFAIL
;
603 ASSERT(spa_config_held(spa
, SCL_ALL
, RW_WRITER
) == SCL_ALL
);
605 for (int c
= 0; c
< vd
->vdev_children
; c
++)
606 if ((error
= vdev_label_init(vd
->vdev_child
[c
],
607 crtxg
, reason
)) != 0)
610 /* Track the creation time for this vdev */
611 vd
->vdev_crtxg
= crtxg
;
613 if (!vd
->vdev_ops
->vdev_op_leaf
)
617 * Dead vdevs cannot be initialized.
619 if (vdev_is_dead(vd
))
623 * Determine if the vdev is in use.
625 if (reason
!= VDEV_LABEL_REMOVE
&& reason
!= VDEV_LABEL_SPLIT
&&
626 vdev_inuse(vd
, crtxg
, reason
, &spare_guid
, &l2cache_guid
))
630 * If this is a request to add or replace a spare or l2cache device
631 * that is in use elsewhere on the system, then we must update the
632 * guid (which was initialized to a random value) to reflect the
633 * actual GUID (which is shared between multiple pools).
635 if (reason
!= VDEV_LABEL_REMOVE
&& reason
!= VDEV_LABEL_L2CACHE
&&
636 spare_guid
!= 0ULL) {
637 uint64_t guid_delta
= spare_guid
- vd
->vdev_guid
;
639 vd
->vdev_guid
+= guid_delta
;
641 for (vdev_t
*pvd
= vd
; pvd
!= NULL
; pvd
= pvd
->vdev_parent
)
642 pvd
->vdev_guid_sum
+= guid_delta
;
645 * If this is a replacement, then we want to fallthrough to the
646 * rest of the code. If we're adding a spare, then it's already
647 * labeled appropriately and we can just return.
649 if (reason
== VDEV_LABEL_SPARE
)
651 ASSERT(reason
== VDEV_LABEL_REPLACE
||
652 reason
== VDEV_LABEL_SPLIT
);
655 if (reason
!= VDEV_LABEL_REMOVE
&& reason
!= VDEV_LABEL_SPARE
&&
656 l2cache_guid
!= 0ULL) {
657 uint64_t guid_delta
= l2cache_guid
- vd
->vdev_guid
;
659 vd
->vdev_guid
+= guid_delta
;
661 for (vdev_t
*pvd
= vd
; pvd
!= NULL
; pvd
= pvd
->vdev_parent
)
662 pvd
->vdev_guid_sum
+= guid_delta
;
665 * If this is a replacement, then we want to fallthrough to the
666 * rest of the code. If we're adding an l2cache, then it's
667 * already labeled appropriately and we can just return.
669 if (reason
== VDEV_LABEL_L2CACHE
)
671 ASSERT(reason
== VDEV_LABEL_REPLACE
);
675 * Initialize its label.
677 vp
= zio_buf_alloc(sizeof (vdev_phys_t
));
678 bzero(vp
, sizeof (vdev_phys_t
));
681 * Generate a label describing the pool and our top-level vdev.
682 * We mark it as being from txg 0 to indicate that it's not
683 * really part of an active pool just yet. The labels will
684 * be written again with a meaningful txg by spa_sync().
686 if (reason
== VDEV_LABEL_SPARE
||
687 (reason
== VDEV_LABEL_REMOVE
&& vd
->vdev_isspare
)) {
689 * For inactive hot spares, we generate a special label that
690 * identifies as a mutually shared hot spare. We write the
691 * label if we are adding a hot spare, or if we are removing an
692 * active hot spare (in which case we want to revert the
695 VERIFY(nvlist_alloc(&label
, NV_UNIQUE_NAME
, KM_SLEEP
) == 0);
697 VERIFY(nvlist_add_uint64(label
, ZPOOL_CONFIG_VERSION
,
698 spa_version(spa
)) == 0);
699 VERIFY(nvlist_add_uint64(label
, ZPOOL_CONFIG_POOL_STATE
,
700 POOL_STATE_SPARE
) == 0);
701 VERIFY(nvlist_add_uint64(label
, ZPOOL_CONFIG_GUID
,
702 vd
->vdev_guid
) == 0);
703 } else if (reason
== VDEV_LABEL_L2CACHE
||
704 (reason
== VDEV_LABEL_REMOVE
&& vd
->vdev_isl2cache
)) {
706 * For level 2 ARC devices, add a special label.
708 VERIFY(nvlist_alloc(&label
, NV_UNIQUE_NAME
, KM_SLEEP
) == 0);
710 VERIFY(nvlist_add_uint64(label
, ZPOOL_CONFIG_VERSION
,
711 spa_version(spa
)) == 0);
712 VERIFY(nvlist_add_uint64(label
, ZPOOL_CONFIG_POOL_STATE
,
713 POOL_STATE_L2CACHE
) == 0);
714 VERIFY(nvlist_add_uint64(label
, ZPOOL_CONFIG_GUID
,
715 vd
->vdev_guid
) == 0);
719 if (reason
== VDEV_LABEL_SPLIT
)
720 txg
= spa
->spa_uberblock
.ub_txg
;
721 label
= spa_config_generate(spa
, vd
, txg
, B_FALSE
);
724 * Add our creation time. This allows us to detect multiple
725 * vdev uses as described above, and automatically expires if we
728 VERIFY(nvlist_add_uint64(label
, ZPOOL_CONFIG_CREATE_TXG
,
733 buflen
= sizeof (vp
->vp_nvlist
);
735 error
= nvlist_pack(label
, &buf
, &buflen
, NV_ENCODE_XDR
, KM_SLEEP
);
738 zio_buf_free(vp
, sizeof (vdev_phys_t
));
739 /* EFAULT means nvlist_pack ran out of room */
740 return (error
== EFAULT
? ENAMETOOLONG
: EINVAL
);
744 * Initialize uberblock template.
746 ub
= zio_buf_alloc(VDEV_UBERBLOCK_RING
);
747 bzero(ub
, VDEV_UBERBLOCK_RING
);
748 *ub
= spa
->spa_uberblock
;
751 /* Initialize the 2nd padding area. */
752 pad2
= zio_buf_alloc(VDEV_PAD_SIZE
);
753 bzero(pad2
, VDEV_PAD_SIZE
);
756 * Write everything in parallel.
759 zio
= zio_root(spa
, NULL
, NULL
, flags
);
761 for (int l
= 0; l
< VDEV_LABELS
; l
++) {
763 vdev_label_write(zio
, vd
, l
, vp
,
764 offsetof(vdev_label_t
, vl_vdev_phys
),
765 sizeof (vdev_phys_t
), NULL
, NULL
, flags
);
768 * Skip the 1st padding area.
769 * Zero out the 2nd padding area where it might have
770 * left over data from previous filesystem format.
772 vdev_label_write(zio
, vd
, l
, pad2
,
773 offsetof(vdev_label_t
, vl_pad2
),
774 VDEV_PAD_SIZE
, NULL
, NULL
, flags
);
776 vdev_label_write(zio
, vd
, l
, ub
,
777 offsetof(vdev_label_t
, vl_uberblock
),
778 VDEV_UBERBLOCK_RING
, NULL
, NULL
, flags
);
781 error
= zio_wait(zio
);
783 if (error
!= 0 && !(flags
& ZIO_FLAG_TRYHARD
)) {
784 flags
|= ZIO_FLAG_TRYHARD
;
789 zio_buf_free(pad2
, VDEV_PAD_SIZE
);
790 zio_buf_free(ub
, VDEV_UBERBLOCK_RING
);
791 zio_buf_free(vp
, sizeof (vdev_phys_t
));
794 * If this vdev hasn't been previously identified as a spare, then we
795 * mark it as such only if a) we are labeling it as a spare, or b) it
796 * exists as a spare elsewhere in the system. Do the same for
797 * level 2 ARC devices.
799 if (error
== 0 && !vd
->vdev_isspare
&&
800 (reason
== VDEV_LABEL_SPARE
||
801 spa_spare_exists(vd
->vdev_guid
, NULL
, NULL
)))
804 if (error
== 0 && !vd
->vdev_isl2cache
&&
805 (reason
== VDEV_LABEL_L2CACHE
||
806 spa_l2cache_exists(vd
->vdev_guid
, NULL
)))
813 * ==========================================================================
814 * uberblock load/sync
815 * ==========================================================================
819 * Consider the following situation: txg is safely synced to disk. We've
820 * written the first uberblock for txg + 1, and then we lose power. When we
821 * come back up, we fail to see the uberblock for txg + 1 because, say,
822 * it was on a mirrored device and the replica to which we wrote txg + 1
823 * is now offline. If we then make some changes and sync txg + 1, and then
824 * the missing replica comes back, then for a new seconds we'll have two
825 * conflicting uberblocks on disk with the same txg. The solution is simple:
826 * among uberblocks with equal txg, choose the one with the latest timestamp.
829 vdev_uberblock_compare(uberblock_t
*ub1
, uberblock_t
*ub2
)
831 if (ub1
->ub_txg
< ub2
->ub_txg
)
833 if (ub1
->ub_txg
> ub2
->ub_txg
)
836 if (ub1
->ub_timestamp
< ub2
->ub_timestamp
)
838 if (ub1
->ub_timestamp
> ub2
->ub_timestamp
)
845 vdev_uberblock_load_done(zio_t
*zio
)
847 spa_t
*spa
= zio
->io_spa
;
848 zio_t
*rio
= zio
->io_private
;
849 uberblock_t
*ub
= zio
->io_data
;
850 uberblock_t
*ubbest
= rio
->io_private
;
852 ASSERT3U(zio
->io_size
, ==, VDEV_UBERBLOCK_SIZE(zio
->io_vd
));
854 if (zio
->io_error
== 0 && uberblock_verify(ub
) == 0) {
855 mutex_enter(&rio
->io_lock
);
856 if (ub
->ub_txg
<= spa
->spa_load_max_txg
&&
857 vdev_uberblock_compare(ub
, ubbest
) > 0)
859 mutex_exit(&rio
->io_lock
);
862 zio_buf_free(zio
->io_data
, zio
->io_size
);
866 vdev_uberblock_load(zio_t
*zio
, vdev_t
*vd
, uberblock_t
*ubbest
)
868 spa_t
*spa
= vd
->vdev_spa
;
869 vdev_t
*rvd
= spa
->spa_root_vdev
;
870 int flags
= ZIO_FLAG_CONFIG_WRITER
| ZIO_FLAG_CANFAIL
|
871 ZIO_FLAG_SPECULATIVE
| ZIO_FLAG_TRYHARD
;
875 spa_config_enter(spa
, SCL_ALL
, FTAG
, RW_WRITER
);
876 zio
= zio_root(spa
, NULL
, ubbest
, flags
);
877 bzero(ubbest
, sizeof (uberblock_t
));
882 for (int c
= 0; c
< vd
->vdev_children
; c
++)
883 vdev_uberblock_load(zio
, vd
->vdev_child
[c
], ubbest
);
885 if (vd
->vdev_ops
->vdev_op_leaf
&& vdev_readable(vd
)) {
886 for (int l
= 0; l
< VDEV_LABELS
; l
++) {
887 for (int n
= 0; n
< VDEV_UBERBLOCK_COUNT(vd
); n
++) {
888 vdev_label_read(zio
, vd
, l
,
889 zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd
)),
890 VDEV_UBERBLOCK_OFFSET(vd
, n
),
891 VDEV_UBERBLOCK_SIZE(vd
),
892 vdev_uberblock_load_done
, zio
, flags
);
898 (void) zio_wait(zio
);
899 spa_config_exit(spa
, SCL_ALL
, FTAG
);
904 * On success, increment root zio's count of good writes.
905 * We only get credit for writes to known-visible vdevs; see spa_vdev_add().
908 vdev_uberblock_sync_done(zio_t
*zio
)
910 uint64_t *good_writes
= zio
->io_private
;
912 if (zio
->io_error
== 0 && zio
->io_vd
->vdev_top
->vdev_ms_array
!= 0)
913 atomic_add_64(good_writes
, 1);
917 * Write the uberblock to all labels of all leaves of the specified vdev.
920 vdev_uberblock_sync(zio_t
*zio
, uberblock_t
*ub
, vdev_t
*vd
, int flags
)
925 for (int c
= 0; c
< vd
->vdev_children
; c
++)
926 vdev_uberblock_sync(zio
, ub
, vd
->vdev_child
[c
], flags
);
928 if (!vd
->vdev_ops
->vdev_op_leaf
)
931 if (!vdev_writeable(vd
))
934 n
= ub
->ub_txg
& (VDEV_UBERBLOCK_COUNT(vd
) - 1);
936 ubbuf
= zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd
));
937 bzero(ubbuf
, VDEV_UBERBLOCK_SIZE(vd
));
940 for (int l
= 0; l
< VDEV_LABELS
; l
++)
941 vdev_label_write(zio
, vd
, l
, ubbuf
,
942 VDEV_UBERBLOCK_OFFSET(vd
, n
), VDEV_UBERBLOCK_SIZE(vd
),
943 vdev_uberblock_sync_done
, zio
->io_private
,
944 flags
| ZIO_FLAG_DONT_PROPAGATE
);
946 zio_buf_free(ubbuf
, VDEV_UBERBLOCK_SIZE(vd
));
950 vdev_uberblock_sync_list(vdev_t
**svd
, int svdcount
, uberblock_t
*ub
, int flags
)
952 spa_t
*spa
= svd
[0]->vdev_spa
;
954 uint64_t good_writes
= 0;
956 zio
= zio_root(spa
, NULL
, &good_writes
, flags
);
958 for (int v
= 0; v
< svdcount
; v
++)
959 vdev_uberblock_sync(zio
, ub
, svd
[v
], flags
);
961 (void) zio_wait(zio
);
964 * Flush the uberblocks to disk. This ensures that the odd labels
965 * are no longer needed (because the new uberblocks and the even
966 * labels are safely on disk), so it is safe to overwrite them.
968 zio
= zio_root(spa
, NULL
, NULL
, flags
);
970 for (int v
= 0; v
< svdcount
; v
++)
971 zio_flush(zio
, svd
[v
]);
973 (void) zio_wait(zio
);
975 return (good_writes
>= 1 ? 0 : EIO
);
979 * On success, increment the count of good writes for our top-level vdev.
982 vdev_label_sync_done(zio_t
*zio
)
984 uint64_t *good_writes
= zio
->io_private
;
986 if (zio
->io_error
== 0)
987 atomic_add_64(good_writes
, 1);
991 * If there weren't enough good writes, indicate failure to the parent.
994 vdev_label_sync_top_done(zio_t
*zio
)
996 uint64_t *good_writes
= zio
->io_private
;
998 if (*good_writes
== 0)
1001 kmem_free(good_writes
, sizeof (uint64_t));
1005 * We ignore errors for log and cache devices, simply free the private data.
1008 vdev_label_sync_ignore_done(zio_t
*zio
)
1010 kmem_free(zio
->io_private
, sizeof (uint64_t));
1014 * Write all even or odd labels to all leaves of the specified vdev.
1017 vdev_label_sync(zio_t
*zio
, vdev_t
*vd
, int l
, uint64_t txg
, int flags
)
1024 for (int c
= 0; c
< vd
->vdev_children
; c
++)
1025 vdev_label_sync(zio
, vd
->vdev_child
[c
], l
, txg
, flags
);
1027 if (!vd
->vdev_ops
->vdev_op_leaf
)
1030 if (!vdev_writeable(vd
))
1034 * Generate a label describing the top-level config to which we belong.
1036 label
= spa_config_generate(vd
->vdev_spa
, vd
, txg
, B_FALSE
);
1038 vp
= zio_buf_alloc(sizeof (vdev_phys_t
));
1039 bzero(vp
, sizeof (vdev_phys_t
));
1041 buf
= vp
->vp_nvlist
;
1042 buflen
= sizeof (vp
->vp_nvlist
);
1044 if (nvlist_pack(label
, &buf
, &buflen
, NV_ENCODE_XDR
, KM_SLEEP
) == 0) {
1045 for (; l
< VDEV_LABELS
; l
+= 2) {
1046 vdev_label_write(zio
, vd
, l
, vp
,
1047 offsetof(vdev_label_t
, vl_vdev_phys
),
1048 sizeof (vdev_phys_t
),
1049 vdev_label_sync_done
, zio
->io_private
,
1050 flags
| ZIO_FLAG_DONT_PROPAGATE
);
1054 zio_buf_free(vp
, sizeof (vdev_phys_t
));
1059 vdev_label_sync_list(spa_t
*spa
, int l
, uint64_t txg
, int flags
)
1061 list_t
*dl
= &spa
->spa_config_dirty_list
;
1067 * Write the new labels to disk.
1069 zio
= zio_root(spa
, NULL
, NULL
, flags
);
1071 for (vd
= list_head(dl
); vd
!= NULL
; vd
= list_next(dl
, vd
)) {
1072 uint64_t *good_writes
= kmem_zalloc(sizeof (uint64_t),
1075 ASSERT(!vd
->vdev_ishole
);
1077 zio_t
*vio
= zio_null(zio
, spa
, NULL
,
1078 (vd
->vdev_islog
|| vd
->vdev_aux
!= NULL
) ?
1079 vdev_label_sync_ignore_done
: vdev_label_sync_top_done
,
1080 good_writes
, flags
);
1081 vdev_label_sync(vio
, vd
, l
, txg
, flags
);
1085 error
= zio_wait(zio
);
1088 * Flush the new labels to disk.
1090 zio
= zio_root(spa
, NULL
, NULL
, flags
);
1092 for (vd
= list_head(dl
); vd
!= NULL
; vd
= list_next(dl
, vd
))
1095 (void) zio_wait(zio
);
1101 * Sync the uberblock and any changes to the vdev configuration.
1103 * The order of operations is carefully crafted to ensure that
1104 * if the system panics or loses power at any time, the state on disk
1105 * is still transactionally consistent. The in-line comments below
1106 * describe the failure semantics at each stage.
1108 * Moreover, vdev_config_sync() is designed to be idempotent: if it fails
1109 * at any time, you can just call it again, and it will resume its work.
1112 vdev_config_sync(vdev_t
**svd
, int svdcount
, uint64_t txg
, boolean_t tryhard
)
1114 spa_t
*spa
= svd
[0]->vdev_spa
;
1115 uberblock_t
*ub
= &spa
->spa_uberblock
;
1119 int flags
= ZIO_FLAG_CONFIG_WRITER
| ZIO_FLAG_CANFAIL
;
1122 * Normally, we don't want to try too hard to write every label and
1123 * uberblock. If there is a flaky disk, we don't want the rest of the
1124 * sync process to block while we retry. But if we can't write a
1125 * single label out, we should retry with ZIO_FLAG_TRYHARD before
1126 * bailing out and declaring the pool faulted.
1129 flags
|= ZIO_FLAG_TRYHARD
;
1131 ASSERT(ub
->ub_txg
<= txg
);
1134 * If this isn't a resync due to I/O errors,
1135 * and nothing changed in this transaction group,
1136 * and the vdev configuration hasn't changed,
1137 * then there's nothing to do.
1139 if (ub
->ub_txg
< txg
&&
1140 uberblock_update(ub
, spa
->spa_root_vdev
, txg
) == B_FALSE
&&
1141 list_is_empty(&spa
->spa_config_dirty_list
))
1144 if (txg
> spa_freeze_txg(spa
))
1147 ASSERT(txg
<= spa
->spa_final_txg
);
1150 * Flush the write cache of every disk that's been written to
1151 * in this transaction group. This ensures that all blocks
1152 * written in this txg will be committed to stable storage
1153 * before any uberblock that references them.
1155 zio
= zio_root(spa
, NULL
, NULL
, flags
);
1157 for (vd
= txg_list_head(&spa
->spa_vdev_txg_list
, TXG_CLEAN(txg
)); vd
;
1158 vd
= txg_list_next(&spa
->spa_vdev_txg_list
, vd
, TXG_CLEAN(txg
)))
1161 (void) zio_wait(zio
);
1164 * Sync out the even labels (L0, L2) for every dirty vdev. If the
1165 * system dies in the middle of this process, that's OK: all of the
1166 * even labels that made it to disk will be newer than any uberblock,
1167 * and will therefore be considered invalid. The odd labels (L1, L3),
1168 * which have not yet been touched, will still be valid. We flush
1169 * the new labels to disk to ensure that all even-label updates
1170 * are committed to stable storage before the uberblock update.
1172 if ((error
= vdev_label_sync_list(spa
, 0, txg
, flags
)) != 0)
1176 * Sync the uberblocks to all vdevs in svd[].
1177 * If the system dies in the middle of this step, there are two cases
1178 * to consider, and the on-disk state is consistent either way:
1180 * (1) If none of the new uberblocks made it to disk, then the
1181 * previous uberblock will be the newest, and the odd labels
1182 * (which had not yet been touched) will be valid with respect
1183 * to that uberblock.
1185 * (2) If one or more new uberblocks made it to disk, then they
1186 * will be the newest, and the even labels (which had all
1187 * been successfully committed) will be valid with respect
1188 * to the new uberblocks.
1190 if ((error
= vdev_uberblock_sync_list(svd
, svdcount
, ub
, flags
)) != 0)
1194 * Sync out odd labels for every dirty vdev. If the system dies
1195 * in the middle of this process, the even labels and the new
1196 * uberblocks will suffice to open the pool. The next time
1197 * the pool is opened, the first thing we'll do -- before any
1198 * user data is modified -- is mark every vdev dirty so that
1199 * all labels will be brought up to date. We flush the new labels
1200 * to disk to ensure that all odd-label updates are committed to
1201 * stable storage before the next transaction group begins.
1203 return (vdev_label_sync_list(spa
, 1, txg
, flags
));