freebsd-nq/module/zfs/zfeature.c

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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2011, 2015 by Delphix. All rights reserved.
*/
#include <sys/zfs_context.h>
#include <sys/zfeature.h>
#include <sys/dmu.h>
#include <sys/nvpair.h>
#include <sys/zap.h>
#include <sys/dmu_tx.h>
#include "zfeature_common.h"
#include <sys/spa_impl.h>
/*
* ZFS Feature Flags
* -----------------
*
* ZFS feature flags are used to provide fine-grained versioning to the ZFS
* on-disk format. Once enabled on a pool feature flags replace the old
* spa_version() number.
*
* Each new on-disk format change will be given a uniquely identifying string
* GUID rather than a version number. This avoids the problem of different
* organizations creating new on-disk formats with the same version number. To
* keep feature GUIDs unique they should consist of the reverse dns name of the
* organization which implemented the feature and a short name for the feature,
* separated by a colon (e.g. com.delphix:async_destroy).
*
* Reference Counts
* ----------------
*
* Within each pool features can be in one of three states: disabled, enabled,
* or active. These states are differentiated by a reference count stored on
* disk for each feature:
*
* 1) If there is no reference count stored on disk the feature is disabled.
* 2) If the reference count is 0 a system administrator has enabled the
* feature, but the feature has not been used yet, so no on-disk
* format changes have been made.
* 3) If the reference count is greater than 0 the feature is active.
* The format changes required by the feature are currently on disk.
* Note that if the feature's format changes are reversed the feature
* may choose to set its reference count back to 0.
*
* Feature flags makes no differentiation between non-zero reference counts
* for an active feature (e.g. a reference count of 1 means the same thing as a
* reference count of 27834721), but feature implementations may choose to use
* the reference count to store meaningful information. For example, a new RAID
* implementation might set the reference count to the number of vdevs using
* it. If all those disks are removed from the pool the feature goes back to
* having a reference count of 0.
*
* It is the responsibility of the individual features to maintain a non-zero
* reference count as long as the feature's format changes are present on disk.
*
* Dependencies
* ------------
*
* Each feature may depend on other features. The only effect of this
* relationship is that when a feature is enabled all of its dependencies are
* automatically enabled as well. Any future work to support disabling of
* features would need to ensure that features cannot be disabled if other
* enabled features depend on them.
*
* On-disk Format
* --------------
*
* When feature flags are enabled spa_version() is set to SPA_VERSION_FEATURES
* (5000). In order for this to work the pool is automatically upgraded to
* SPA_VERSION_BEFORE_FEATURES (28) first, so all pre-feature flags on disk
* format changes will be in use.
*
* Information about features is stored in 3 ZAP objects in the pool's MOS.
* These objects are linked to by the following names in the pool directory
* object:
*
* 1) features_for_read: feature GUID -> reference count
* Features needed to open the pool for reading.
* 2) features_for_write: feature GUID -> reference count
* Features needed to open the pool for writing.
* 3) feature_descriptions: feature GUID -> descriptive string
* A human readable string.
*
* All enabled features appear in either features_for_read or
* features_for_write, but not both.
*
* To open a pool in read-only mode only the features listed in
* features_for_read need to be supported.
*
* To open the pool in read-write mode features in both features_for_read and
* features_for_write need to be supported.
*
* Some features may be required to read the ZAP objects containing feature
* information. To allow software to check for compatibility with these features
* before the pool is opened their names must be stored in the label in a
* new "features_for_read" entry (note that features that are only required
* to write to a pool never need to be stored in the label since the
* features_for_write ZAP object can be read before the pool is written to).
* To save space in the label features must be explicitly marked as needing to
* be written to the label. Also, reference counts are not stored in the label,
* instead any feature whose reference count drops to 0 is removed from the
* label.
*
* Adding New Features
* -------------------
*
* Features must be registered in zpool_feature_init() function in
* zfeature_common.c using the zfeature_register() function. This function
* has arguments to specify if the feature should be stored in the
* features_for_read or features_for_write ZAP object and if it needs to be
* written to the label when active.
*
* Once a feature is registered it will appear as a "feature@<feature name>"
* property which can be set by an administrator. Feature implementors should
* use the spa_feature_is_enabled() and spa_feature_is_active() functions to
* query the state of a feature and the spa_feature_incr() and
* spa_feature_decr() functions to change an enabled feature's reference count.
* Reference counts may only be updated in the syncing context.
*
* Features may not perform enable-time initialization. Instead, any such
* initialization should occur when the feature is first used. This design
* enforces that on-disk changes be made only when features are used. Code
* should only check if a feature is enabled using spa_feature_is_enabled(),
* not by relying on any feature specific metadata existing. If a feature is
* enabled, but the feature's metadata is not on disk yet then it should be
* created as needed.
*
* As an example, consider the com.delphix:async_destroy feature. This feature
* relies on the existence of a bptree in the MOS that store blocks for
* asynchronous freeing. This bptree is not created when async_destroy is
* enabled. Instead, when a dataset is destroyed spa_feature_is_enabled() is
* called to check if async_destroy is enabled. If it is and the bptree object
* does not exist yet, the bptree object is created as part of the dataset
* destroy and async_destroy's reference count is incremented to indicate it
* has made an on-disk format change. Later, after the destroyed dataset's
* blocks have all been asynchronously freed there is no longer any use for the
* bptree object, so it is destroyed and async_destroy's reference count is
* decremented back to 0 to indicate that it has undone its on-disk format
* changes.
*/
typedef enum {
FEATURE_ACTION_INCR,
FEATURE_ACTION_DECR,
} feature_action_t;
/*
* Checks that the active features in the pool are supported by
* this software. Adds each unsupported feature (name -> description) to
* the supplied nvlist.
*/
boolean_t
spa_features_check(spa_t *spa, boolean_t for_write,
nvlist_t *unsup_feat, nvlist_t *enabled_feat)
{
objset_t *os = spa->spa_meta_objset;
boolean_t supported;
zap_cursor_t *zc;
zap_attribute_t *za;
uint64_t obj = for_write ?
spa->spa_feat_for_write_obj : spa->spa_feat_for_read_obj;
char *buf;
zc = kmem_alloc(sizeof (zap_cursor_t), KM_SLEEP);
za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
buf = kmem_alloc(MAXPATHLEN, KM_SLEEP);
supported = B_TRUE;
for (zap_cursor_init(zc, os, obj);
zap_cursor_retrieve(zc, za) == 0;
zap_cursor_advance(zc)) {
ASSERT(za->za_integer_length == sizeof (uint64_t) &&
za->za_num_integers == 1);
if (NULL != enabled_feat) {
fnvlist_add_uint64(enabled_feat, za->za_name,
za->za_first_integer);
}
if (za->za_first_integer != 0 &&
!zfeature_is_supported(za->za_name)) {
supported = B_FALSE;
if (NULL != unsup_feat) {
char *desc = "";
if (zap_lookup(os, spa->spa_feat_desc_obj,
za->za_name, 1, MAXPATHLEN, buf) == 0)
desc = buf;
VERIFY(nvlist_add_string(unsup_feat,
za->za_name, desc) == 0);
}
}
}
zap_cursor_fini(zc);
kmem_free(buf, MAXPATHLEN);
kmem_free(za, sizeof (zap_attribute_t));
kmem_free(zc, sizeof (zap_cursor_t));
return (supported);
}
/*
* Use an in-memory cache of feature refcounts for quick retrieval.
*
* Note: well-designed features will not need to use this; they should
* use spa_feature_is_enabled() and spa_feature_is_active() instead.
* However, this is non-static for zdb, zhack, and spa_add_feature_stats().
*/
int
feature_get_refcount(spa_t *spa, zfeature_info_t *feature, uint64_t *res)
{
ASSERT(VALID_FEATURE_FID(feature->fi_feature));
if (spa->spa_feat_refcount_cache[feature->fi_feature] ==
SPA_FEATURE_DISABLED) {
return (SET_ERROR(ENOTSUP));
}
*res = spa->spa_feat_refcount_cache[feature->fi_feature];
return (0);
}
/*
* Note: well-designed features will not need to use this; they should
* use spa_feature_is_enabled() and spa_feature_is_active() instead.
* However, this is non-static for zdb and zhack.
*/
int
feature_get_refcount_from_disk(spa_t *spa, zfeature_info_t *feature,
uint64_t *res)
{
int err;
uint64_t refcount;
uint64_t zapobj = (feature->fi_flags & ZFEATURE_FLAG_READONLY_COMPAT) ?
spa->spa_feat_for_write_obj : spa->spa_feat_for_read_obj;
/*
* If the pool is currently being created, the feature objects may not
* have been allocated yet. Act as though all features are disabled.
*/
if (zapobj == 0)
return (SET_ERROR(ENOTSUP));
err = zap_lookup(spa->spa_meta_objset, zapobj,
feature->fi_guid, sizeof (uint64_t), 1, &refcount);
if (err != 0) {
if (err == ENOENT)
return (SET_ERROR(ENOTSUP));
else
return (err);
}
*res = refcount;
return (0);
}
static int
feature_get_enabled_txg(spa_t *spa, zfeature_info_t *feature, uint64_t *res)
{
uint64_t enabled_txg_obj __maybe_unused = spa->spa_feat_enabled_txg_obj;
ASSERT(zfeature_depends_on(feature->fi_feature,
SPA_FEATURE_ENABLED_TXG));
if (!spa_feature_is_enabled(spa, feature->fi_feature)) {
return (SET_ERROR(ENOTSUP));
}
ASSERT(enabled_txg_obj != 0);
VERIFY0(zap_lookup(spa->spa_meta_objset, spa->spa_feat_enabled_txg_obj,
feature->fi_guid, sizeof (uint64_t), 1, res));
return (0);
}
/*
* This function is non-static for zhack; it should otherwise not be used
* outside this file.
*/
void
feature_sync(spa_t *spa, zfeature_info_t *feature, uint64_t refcount,
dmu_tx_t *tx)
{
ASSERT(VALID_FEATURE_OR_NONE(feature->fi_feature));
uint64_t zapobj = (feature->fi_flags & ZFEATURE_FLAG_READONLY_COMPAT) ?
spa->spa_feat_for_write_obj : spa->spa_feat_for_read_obj;
VERIFY0(zap_update(spa->spa_meta_objset, zapobj, feature->fi_guid,
sizeof (uint64_t), 1, &refcount, tx));
/*
* feature_sync is called directly from zhack, allowing the
* creation of arbitrary features whose fi_feature field may
* be greater than SPA_FEATURES. When called from zhack, the
* zfeature_info_t object's fi_feature field will be set to
* SPA_FEATURE_NONE.
*/
if (feature->fi_feature != SPA_FEATURE_NONE) {
uint64_t *refcount_cache =
&spa->spa_feat_refcount_cache[feature->fi_feature];
VERIFY3U(*refcount_cache, ==,
atomic_swap_64(refcount_cache, refcount));
}
if (refcount == 0)
spa_deactivate_mos_feature(spa, feature->fi_guid);
else if (feature->fi_flags & ZFEATURE_FLAG_MOS)
spa_activate_mos_feature(spa, feature->fi_guid, tx);
}
/*
* This function is non-static for zhack; it should otherwise not be used
* outside this file.
*/
void
feature_enable_sync(spa_t *spa, zfeature_info_t *feature, dmu_tx_t *tx)
{
uint64_t initial_refcount =
(feature->fi_flags & ZFEATURE_FLAG_ACTIVATE_ON_ENABLE) ? 1 : 0;
uint64_t zapobj = (feature->fi_flags & ZFEATURE_FLAG_READONLY_COMPAT) ?
spa->spa_feat_for_write_obj : spa->spa_feat_for_read_obj;
ASSERT(0 != zapobj);
ASSERT(zfeature_is_valid_guid(feature->fi_guid));
ASSERT3U(spa_version(spa), >=, SPA_VERSION_FEATURES);
/*
* If the feature is already enabled, ignore the request.
*/
if (zap_contains(spa->spa_meta_objset, zapobj, feature->fi_guid) == 0)
return;
for (int i = 0; feature->fi_depends[i] != SPA_FEATURE_NONE; i++)
spa_feature_enable(spa, feature->fi_depends[i], tx);
VERIFY0(zap_update(spa->spa_meta_objset, spa->spa_feat_desc_obj,
feature->fi_guid, 1, strlen(feature->fi_desc) + 1,
feature->fi_desc, tx));
feature_sync(spa, feature, initial_refcount, tx);
if (spa_feature_is_enabled(spa, SPA_FEATURE_ENABLED_TXG)) {
uint64_t enabling_txg = dmu_tx_get_txg(tx);
if (spa->spa_feat_enabled_txg_obj == 0ULL) {
spa->spa_feat_enabled_txg_obj =
zap_create_link(spa->spa_meta_objset,
DMU_OTN_ZAP_METADATA, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_FEATURE_ENABLED_TXG, tx);
}
spa_feature_incr(spa, SPA_FEATURE_ENABLED_TXG, tx);
VERIFY0(zap_add(spa->spa_meta_objset,
spa->spa_feat_enabled_txg_obj, feature->fi_guid,
sizeof (uint64_t), 1, &enabling_txg, tx));
}
/*
* Errata #4 is mostly a problem with encrypted datasets, but it
* is also a problem where the old encryption feature did not
* depend on the bookmark_v2 feature. If the pool does not have
* any encrypted datasets we can resolve this issue simply by
* enabling this dependency.
*/
if (spa->spa_errata == ZPOOL_ERRATA_ZOL_8308_ENCRYPTION &&
spa_feature_is_enabled(spa, SPA_FEATURE_ENCRYPTION) &&
!spa_feature_is_active(spa, SPA_FEATURE_ENCRYPTION) &&
feature->fi_feature == SPA_FEATURE_BOOKMARK_V2)
spa->spa_errata = 0;
}
static void
feature_do_action(spa_t *spa, spa_feature_t fid, feature_action_t action,
dmu_tx_t *tx)
{
uint64_t refcount = 0;
zfeature_info_t *feature = &spa_feature_table[fid];
uint64_t zapobj __maybe_unused =
(feature->fi_flags & ZFEATURE_FLAG_READONLY_COMPAT) ?
spa->spa_feat_for_write_obj : spa->spa_feat_for_read_obj;
ASSERT(VALID_FEATURE_FID(fid));
ASSERT(0 != zapobj);
ASSERT(zfeature_is_valid_guid(feature->fi_guid));
ASSERT(dmu_tx_is_syncing(tx));
ASSERT3U(spa_version(spa), >=, SPA_VERSION_FEATURES);
VERIFY3U(feature_get_refcount(spa, feature, &refcount), !=, ENOTSUP);
switch (action) {
case FEATURE_ACTION_INCR:
VERIFY3U(refcount, !=, UINT64_MAX);
refcount++;
break;
case FEATURE_ACTION_DECR:
VERIFY3U(refcount, !=, 0);
refcount--;
break;
default:
ASSERT(0);
break;
}
feature_sync(spa, feature, refcount, tx);
}
void
spa_feature_create_zap_objects(spa_t *spa, dmu_tx_t *tx)
{
/*
* We create feature flags ZAP objects in two instances: during pool
* creation and during pool upgrade.
*/
Native Encryption for ZFS on Linux This change incorporates three major pieces: The first change is a keystore that manages wrapping and encryption keys for encrypted datasets. These commands mostly involve manipulating the new DSL Crypto Key ZAP Objects that live in the MOS. Each encrypted dataset has its own DSL Crypto Key that is protected with a user's key. This level of indirection allows users to change their keys without re-encrypting their entire datasets. The change implements the new subcommands "zfs load-key", "zfs unload-key" and "zfs change-key" which allow the user to manage their encryption keys and settings. In addition, several new flags and properties have been added to allow dataset creation and to make mounting and unmounting more convenient. The second piece of this patch provides the ability to encrypt, decyrpt, and authenticate protected datasets. Each object set maintains a Merkel tree of Message Authentication Codes that protect the lower layers, similarly to how checksums are maintained. This part impacts the zio layer, which handles the actual encryption and generation of MACs, as well as the ARC and DMU, which need to be able to handle encrypted buffers and protected data. The last addition is the ability to do raw, encrypted sends and receives. The idea here is to send raw encrypted and compressed data and receive it exactly as is on a backup system. This means that the dataset on the receiving system is protected using the same user key that is in use on the sending side. By doing so, datasets can be efficiently backed up to an untrusted system without fear of data being compromised. Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Jorgen Lundman <lundman@lundman.net> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #494 Closes #5769
2017-08-14 17:36:48 +00:00
ASSERT((!spa->spa_sync_on && tx->tx_txg == TXG_INITIAL) ||
dsl_pool_sync_context(spa_get_dsl(spa)));
spa->spa_feat_for_read_obj = zap_create_link(spa->spa_meta_objset,
DMU_OTN_ZAP_METADATA, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_FEATURES_FOR_READ, tx);
spa->spa_feat_for_write_obj = zap_create_link(spa->spa_meta_objset,
DMU_OTN_ZAP_METADATA, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_FEATURES_FOR_WRITE, tx);
spa->spa_feat_desc_obj = zap_create_link(spa->spa_meta_objset,
DMU_OTN_ZAP_METADATA, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_FEATURE_DESCRIPTIONS, tx);
}
/*
* Enable any required dependencies, then enable the requested feature.
*/
void
spa_feature_enable(spa_t *spa, spa_feature_t fid, dmu_tx_t *tx)
{
ASSERT3U(spa_version(spa), >=, SPA_VERSION_FEATURES);
ASSERT(VALID_FEATURE_FID(fid));
feature_enable_sync(spa, &spa_feature_table[fid], tx);
}
void
spa_feature_incr(spa_t *spa, spa_feature_t fid, dmu_tx_t *tx)
{
feature_do_action(spa, fid, FEATURE_ACTION_INCR, tx);
}
void
spa_feature_decr(spa_t *spa, spa_feature_t fid, dmu_tx_t *tx)
{
feature_do_action(spa, fid, FEATURE_ACTION_DECR, tx);
Illumos #4101, #4102, #4103, #4105, #4106 4101 metaslab_debug should allow for fine-grained control 4102 space_maps should store more information about themselves 4103 space map object blocksize should be increased 4105 removing a mirrored log device results in a leaked object 4106 asynchronously load metaslab Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: Adam Leventhal <ahl@delphix.com> Reviewed by: Sebastien Roy <seb@delphix.com> Approved by: Garrett D'Amore <garrett@damore.org> Prior to this patch, space_maps were preferred solely based on the amount of free space left in each. Unfortunately, this heuristic didn't contain any information about the make-up of that free space, which meant we could keep preferring and loading a highly fragmented space map that wouldn't actually have enough contiguous space to satisfy the allocation; then unloading that space_map and repeating the process. This change modifies the space_map's to store additional information about the contiguous space in the space_map, so that we can use this information to make a better decision about which space_map to load. This requires reallocating all space_map objects to increase their bonus buffer size sizes enough to fit the new metadata. The above feature can be enabled via a new feature flag introduced by this change: com.delphix:spacemap_histogram In addition to the above, this patch allows the space_map block size to be increase. Currently the block size is set to be 4K in size, which has certain implications including the following: * 4K sector devices will not see any compression benefit * large space_maps require more metadata on-disk * large space_maps require more time to load (typically random reads) Now the space_map block size can adjust as needed up to the maximum size set via the space_map_max_blksz variable. A bug was fixed which resulted in potentially leaking an object when removing a mirrored log device. The previous logic for vdev_remove() did not deal with removing top-level vdevs that are interior vdevs (i.e. mirror) correctly. The problem would occur when removing a mirrored log device, and result in the DTL space map object being leaked; because top-level vdevs don't have DTL space map objects associated with them. References: https://www.illumos.org/issues/4101 https://www.illumos.org/issues/4102 https://www.illumos.org/issues/4103 https://www.illumos.org/issues/4105 https://www.illumos.org/issues/4106 https://github.com/illumos/illumos-gate/commit/0713e23 Porting notes: A handful of kmem_alloc() calls were converted to kmem_zalloc(). Also, the KM_PUSHPAGE and TQ_PUSHPAGE flags were used as necessary. Ported-by: Tim Chase <tim@chase2k.com> Signed-off-by: Prakash Surya <surya1@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #2488
2013-10-01 21:25:53 +00:00
}
boolean_t
spa_feature_is_enabled(spa_t *spa, spa_feature_t fid)
{
int err;
uint64_t refcount = 0;
ASSERT(VALID_FEATURE_FID(fid));
if (spa_version(spa) < SPA_VERSION_FEATURES)
return (B_FALSE);
err = feature_get_refcount(spa, &spa_feature_table[fid], &refcount);
ASSERT(err == 0 || err == ENOTSUP);
return (err == 0);
}
boolean_t
spa_feature_is_active(spa_t *spa, spa_feature_t fid)
{
int err;
uint64_t refcount = 0;
ASSERT(VALID_FEATURE_FID(fid));
if (spa_version(spa) < SPA_VERSION_FEATURES)
return (B_FALSE);
err = feature_get_refcount(spa, &spa_feature_table[fid], &refcount);
ASSERT(err == 0 || err == ENOTSUP);
return (err == 0 && refcount > 0);
}
/*
* For the feature specified by fid (which must depend on
* SPA_FEATURE_ENABLED_TXG), return the TXG at which it was enabled in the
* OUT txg argument.
*
* Returns B_TRUE if the feature is enabled, in which case txg will be filled
* with the transaction group in which the specified feature was enabled.
* Returns B_FALSE otherwise (i.e. if the feature is not enabled).
*/
boolean_t
spa_feature_enabled_txg(spa_t *spa, spa_feature_t fid, uint64_t *txg)
{
int err;
ASSERT(VALID_FEATURE_FID(fid));
if (spa_version(spa) < SPA_VERSION_FEATURES)
return (B_FALSE);
err = feature_get_enabled_txg(spa, &spa_feature_table[fid], txg);
ASSERT(err == 0 || err == ENOTSUP);
return (err == 0);
}