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-rw-r--r--module/zfs/mmp.c110
-rw-r--r--module/zfs/spa_misc.c4
-rw-r--r--module/zfs/vdev.c13
3 files changed, 61 insertions, 66 deletions
diff --git a/module/zfs/mmp.c b/module/zfs/mmp.c
index 746ee0f77..16975dd98 100644
--- a/module/zfs/mmp.c
+++ b/module/zfs/mmp.c
@@ -205,80 +205,57 @@ typedef enum mmp_vdev_state_flag {
MMP_FAIL_WRITE_PENDING = (1 << 1),
} mmp_vdev_state_flag_t;
-static vdev_t *
-mmp_random_leaf_impl(vdev_t *vd, int *fail_mask)
-{
- int child_idx;
-
- if (vd->vdev_ops->vdev_op_leaf) {
- vdev_t *ret;
-
- if (!vdev_writeable(vd)) {
- *fail_mask |= MMP_FAIL_NOT_WRITABLE;
- ret = NULL;
- } else if (vd->vdev_mmp_pending != 0) {
- *fail_mask |= MMP_FAIL_WRITE_PENDING;
- ret = NULL;
- } else {
- ret = vd;
- }
-
- return (ret);
- }
-
- if (vd->vdev_children == 0)
- return (NULL);
-
- child_idx = spa_get_random(vd->vdev_children);
- for (int offset = vd->vdev_children; offset > 0; offset--) {
- vdev_t *leaf;
- vdev_t *child = vd->vdev_child[(child_idx + offset) %
- vd->vdev_children];
-
- leaf = mmp_random_leaf_impl(child, fail_mask);
- if (leaf)
- return (leaf);
- }
-
- return (NULL);
-}
-
/*
* Find a leaf vdev to write an MMP block to. It must not have an outstanding
* mmp write (if so a new write will also likely block). If there is no usable
- * leaf in the tree rooted at in_vd, a nonzero error value is returned, and
- * *out_vd is unchanged.
- *
- * The error value returned is a bit field.
- *
- * MMP_FAIL_WRITE_PENDING
- * If set, one or more leaf vdevs are writeable, but have an MMP write which has
- * not yet completed.
- *
- * MMP_FAIL_NOT_WRITABLE
- * If set, one or more vdevs are not writeable. The children of those vdevs
- * were not examined.
+ * leaf, a nonzero error value is returned. The error value returned is a bit
+ * field.
*
- * Assuming in_vd points to a tree, a random subtree will be chosen to start.
- * That subtree, and successive ones, will be walked until a usable leaf has
- * been found, or all subtrees have been examined (except that the children of
- * un-writeable vdevs are not examined).
- *
- * If the leaf vdevs in the tree are healthy, the distribution of returned leaf
- * vdevs will be even. If there are unhealthy leaves, the following leaves
- * (child_index % index_children) will be chosen more often.
+ * MMP_FAIL_WRITE_PENDING One or more leaf vdevs are writeable, but have an
+ * outstanding MMP write.
+ * MMP_FAIL_NOT_WRITABLE One or more leaf vdevs are not writeable.
*/
static int
-mmp_random_leaf(vdev_t *in_vd, vdev_t **out_vd)
+mmp_next_leaf(spa_t *spa)
{
- int error_mask = 0;
- vdev_t *vd = mmp_random_leaf_impl(in_vd, &error_mask);
+ vdev_t *leaf;
+ vdev_t *starting_leaf;
+ int fail_mask = 0;
+
+ ASSERT(MUTEX_HELD(&spa->spa_mmp.mmp_io_lock));
+ ASSERT(spa_config_held(spa, SCL_STATE, RW_READER));
+ ASSERT(list_link_active(&spa->spa_leaf_list.list_head) == B_TRUE);
+ ASSERT(!list_is_empty(&spa->spa_leaf_list));
+
+ if (spa->spa_mmp.mmp_leaf_last_gen != spa->spa_leaf_list_gen) {
+ spa->spa_mmp.mmp_last_leaf = list_head(&spa->spa_leaf_list);
+ spa->spa_mmp.mmp_leaf_last_gen = spa->spa_leaf_list_gen;
+ }
+
+ leaf = spa->spa_mmp.mmp_last_leaf;
+ if (leaf == NULL)
+ leaf = list_head(&spa->spa_leaf_list);
+ starting_leaf = leaf;
- if (error_mask == 0)
- *out_vd = vd;
+ do {
+ leaf = list_next(&spa->spa_leaf_list, leaf);
+ if (leaf == NULL)
+ leaf = list_head(&spa->spa_leaf_list);
- return (error_mask);
+ if (!vdev_writeable(leaf)) {
+ fail_mask |= MMP_FAIL_NOT_WRITABLE;
+ } else if (leaf->vdev_mmp_pending != 0) {
+ fail_mask |= MMP_FAIL_WRITE_PENDING;
+ } else {
+ spa->spa_mmp.mmp_last_leaf = leaf;
+ return (0);
+ }
+ } while (leaf != starting_leaf);
+
+ ASSERT(fail_mask);
+
+ return (fail_mask);
}
/*
@@ -398,10 +375,10 @@ mmp_write_uberblock(spa_t *spa)
zfs_dbgmsg("SCL_STATE acquisition took %llu ns\n",
(u_longlong_t)lock_acquire_time);
- error = mmp_random_leaf(spa->spa_root_vdev, &vd);
-
mutex_enter(&mmp->mmp_io_lock);
+ error = mmp_next_leaf(spa);
+
/*
* spa_mmp_history has two types of entries:
* Issued MMP write: records time issued, error status, etc.
@@ -425,6 +402,7 @@ mmp_write_uberblock(spa_t *spa)
return;
}
+ vd = spa->spa_mmp.mmp_last_leaf;
mmp->mmp_skip_error = 0;
if (mmp->mmp_zio_root == NULL)
diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c
index 0976cc49c..71221b21b 100644
--- a/module/zfs/spa_misc.c
+++ b/module/zfs/spa_misc.c
@@ -730,6 +730,9 @@ spa_add(const char *name, nvlist_t *config, const char *altroot)
spa->spa_feat_refcount_cache[i] = SPA_FEATURE_DISABLED;
}
+ list_create(&spa->spa_leaf_list, sizeof (vdev_t),
+ offsetof(vdev_t, vdev_leaf_node));
+
return (spa);
}
@@ -772,6 +775,7 @@ spa_remove(spa_t *spa)
sizeof (avl_tree_t));
list_destroy(&spa->spa_config_list);
+ list_destroy(&spa->spa_leaf_list);
nvlist_free(spa->spa_label_features);
nvlist_free(spa->spa_load_info);
diff --git a/module/zfs/vdev.c b/module/zfs/vdev.c
index 1332c720f..890bb1135 100644
--- a/module/zfs/vdev.c
+++ b/module/zfs/vdev.c
@@ -398,6 +398,11 @@ vdev_add_child(vdev_t *pvd, vdev_t *cvd)
*/
for (; pvd != NULL; pvd = pvd->vdev_parent)
pvd->vdev_guid_sum += cvd->vdev_guid_sum;
+
+ if (cvd->vdev_ops->vdev_op_leaf) {
+ list_insert_head(&cvd->vdev_spa->spa_leaf_list, cvd);
+ cvd->vdev_spa->spa_leaf_list_gen++;
+ }
}
void
@@ -427,6 +432,12 @@ vdev_remove_child(vdev_t *pvd, vdev_t *cvd)
pvd->vdev_children = 0;
}
+ if (cvd->vdev_ops->vdev_op_leaf) {
+ spa_t *spa = cvd->vdev_spa;
+ list_remove(&spa->spa_leaf_list, cvd);
+ spa->spa_leaf_list_gen++;
+ }
+
/*
* Walk up all ancestors to update guid sum.
*/
@@ -531,6 +542,7 @@ vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
list_link_init(&vd->vdev_config_dirty_node);
list_link_init(&vd->vdev_state_dirty_node);
list_link_init(&vd->vdev_initialize_node);
+ list_link_init(&vd->vdev_leaf_node);
mutex_init(&vd->vdev_dtl_lock, NULL, MUTEX_NOLOCKDEP, NULL);
mutex_init(&vd->vdev_stat_lock, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&vd->vdev_probe_lock, NULL, MUTEX_DEFAULT, NULL);
@@ -914,6 +926,7 @@ vdev_free(vdev_t *vd)
vdev_remove_child(vd->vdev_parent, vd);
ASSERT(vd->vdev_parent == NULL);
+ ASSERT(!list_link_active(&vd->vdev_leaf_node));
/*
* Clean up vdev structure.