Author: mav
Date: Thu Apr 25 15:31:35 2019
New Revision: 346676
URL: https://svnweb.freebsd.org/changeset/base/346676
Log:
MFC r337594 (by mmacy):
ZFS/MFV: Use cached feature info in spa_add_feature_stats()
commit 417104bdd3c7ce07ec58674dd078f9891c3bc780
Author: Ned Bass <ba...@llnl.gov>
Date: Thu Feb 26 12:24:11 2015 -0800
Use cached feature info in spa_add_feature_stats()
Avoid issuing I/O to the pool when retrieving feature flags information.
Trying to read the ZAPs from disk means that zpool clear would hang if
the pool is suspended and recovery would require a reboot. To keep the
feature stats resident in memory, we hang a cached nvlist off of the
spa. It is built up from disk the first time spa_add_feature_stats() is
called, and refreshed thereafter using the cached feature reference
counts. spa_add_feature_stats() gets called at pool import time so we
can be sure the cached nvlist will be available if the pool is later
suspended.
Signed-off-by: Ned Bass <ba...@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendo...@llnl.gov>
Closes #3082
Modified:
stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c
stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h
stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfeature.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
==============================================================================
--- stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c Thu Apr
25 15:09:21 2019 (r346675)
+++ stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c Thu Apr
25 15:31:35 2019 (r346676)
@@ -4372,18 +4372,14 @@ spa_add_l2cache(spa_t *spa, nvlist_t *config)
}
static void
-spa_add_feature_stats(spa_t *spa, nvlist_t *config)
+spa_feature_stats_from_disk(spa_t *spa, nvlist_t *features)
{
- nvlist_t *features;
zap_cursor_t zc;
zap_attribute_t za;
- ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER));
- VERIFY(nvlist_alloc(&features, NV_UNIQUE_NAME, KM_SLEEP) == 0);
-
/* We may be unable to read features if pool is suspended. */
if (spa_suspended(spa))
- goto out;
+ return;
if (spa->spa_feat_for_read_obj != 0) {
for (zap_cursor_init(&zc, spa->spa_meta_objset,
@@ -4392,7 +4388,7 @@ spa_add_feature_stats(spa_t *spa, nvlist_t *config)
zap_cursor_advance(&zc)) {
ASSERT(za.za_integer_length == sizeof (uint64_t) &&
za.za_num_integers == 1);
- VERIFY3U(0, ==, nvlist_add_uint64(features, za.za_name,
+ VERIFY0(nvlist_add_uint64(features, za.za_name,
za.za_first_integer));
}
zap_cursor_fini(&zc);
@@ -4405,16 +4401,62 @@ spa_add_feature_stats(spa_t *spa, nvlist_t *config)
zap_cursor_advance(&zc)) {
ASSERT(za.za_integer_length == sizeof (uint64_t) &&
za.za_num_integers == 1);
- VERIFY3U(0, ==, nvlist_add_uint64(features, za.za_name,
+ VERIFY0(nvlist_add_uint64(features, za.za_name,
za.za_first_integer));
}
zap_cursor_fini(&zc);
}
+}
-out:
- VERIFY(nvlist_add_nvlist(config, ZPOOL_CONFIG_FEATURE_STATS,
- features) == 0);
- nvlist_free(features);
+static void
+spa_feature_stats_from_cache(spa_t *spa, nvlist_t *features)
+{
+ int i;
+
+ for (i = 0; i < SPA_FEATURES; i++) {
+ zfeature_info_t feature = spa_feature_table[i];
+ uint64_t refcount;
+
+ if (feature_get_refcount(spa, &feature, &refcount) != 0)
+ continue;
+
+ VERIFY0(nvlist_add_uint64(features, feature.fi_guid, refcount));
+ }
+}
+
+/*
+ * Store a list of pool features and their reference counts in the
+ * config.
+ *
+ * The first time this is called on a spa, allocate a new nvlist, fetch
+ * the pool features and reference counts from disk, then save the list
+ * in the spa. In subsequent calls on the same spa use the saved nvlist
+ * and refresh its values from the cached reference counts. This
+ * ensures we don't block here on I/O on a suspended pool so 'zpool
+ * clear' can resume the pool.
+ */
+static void
+spa_add_feature_stats(spa_t *spa, nvlist_t *config)
+{
+ nvlist_t *features;
+
+ ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER));
+
+ mutex_enter(&spa->spa_feat_stats_lock);
+ features = spa->spa_feat_stats;
+
+ if (features != NULL) {
+ spa_feature_stats_from_cache(spa, features);
+ } else {
+ VERIFY0(nvlist_alloc(&features, NV_UNIQUE_NAME, KM_SLEEP));
+ spa->spa_feat_stats = features;
+ spa_feature_stats_from_disk(spa, features);
+ }
+
+ VERIFY0(nvlist_add_nvlist(config, ZPOOL_CONFIG_FEATURE_STATS,
+ features));
+
+ mutex_exit(&spa->spa_feat_stats_lock);
}
int
Modified: stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c
==============================================================================
--- stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c Thu Apr
25 15:09:21 2019 (r346675)
+++ stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c Thu Apr
25 15:31:35 2019 (r346676)
@@ -716,6 +716,7 @@ spa_add(const char *name, nvlist_t *config, const char
mutex_init(&spa->spa_scrub_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa->spa_suspend_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&spa->spa_vdev_top_lock, NULL, MUTEX_DEFAULT, NULL);
+ mutex_init(&spa->spa_feat_stats_lock, NULL, MUTEX_DEFAULT, NULL);
cv_init(&spa->spa_async_cv, NULL, CV_DEFAULT, NULL);
cv_init(&spa->spa_evicting_os_cv, NULL, CV_DEFAULT, NULL);
@@ -889,6 +890,7 @@ spa_remove(spa_t *spa)
nvlist_free(spa->spa_label_features);
nvlist_free(spa->spa_load_info);
+ nvlist_free(spa->spa_feat_stats);
spa_config_set(spa, NULL);
#ifdef illumos
@@ -930,6 +932,7 @@ spa_remove(spa_t *spa)
mutex_destroy(&spa->spa_scrub_lock);
mutex_destroy(&spa->spa_suspend_lock);
mutex_destroy(&spa->spa_vdev_top_lock);
+ mutex_destroy(&spa->spa_feat_stats_lock);
kmem_free(spa, sizeof (spa_t));
}
Modified:
stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h
==============================================================================
--- stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h
Thu Apr 25 15:09:21 2019 (r346675)
+++ stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h
Thu Apr 25 15:31:35 2019 (r346676)
@@ -360,6 +360,8 @@ struct spa {
uint64_t spa_feat_for_read_obj; /* required to read from pool */
uint64_t spa_feat_desc_obj; /* Feature descriptions */
uint64_t spa_feat_enabled_txg_obj; /* Feature enabled txg */
+ kmutex_t spa_feat_stats_lock; /* protects spa_feat_stats */
+ nvlist_t *spa_feat_stats; /* Cache of enabled features */
/* cache feature refcounts */
uint64_t spa_feat_refcount_cache[SPA_FEATURES];
#ifdef illumos
Modified: stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfeature.c
==============================================================================
--- stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfeature.c Thu Apr
25 15:09:21 2019 (r346675)
+++ stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfeature.c Thu Apr
25 15:31:35 2019 (r346676)
@@ -220,7 +220,7 @@ spa_features_check(spa_t *spa, boolean_t for_write,
*
* 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.
+ * 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)
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