Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3106 insertions, 0 deletions

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
new file mode 100644
index 0000000000..2950988738
--- /dev/null
+++ b/net/ceph/osdmap.c
@@ -0,0 +1,3106 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include <linux/ceph/libceph.h>
+#include <linux/ceph/osdmap.h>
+#include <linux/ceph/decode.h>
+#include <linux/crush/hash.h>
+#include <linux/crush/mapper.h>
+
+static __printf(2, 3)
+void osdmap_info(const struct ceph_osdmap *map, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	printk(KERN_INFO "%s (%pU e%u): %pV", KBUILD_MODNAME, &map->fsid,
+	       map->epoch, &vaf);
+
+	va_end(args);
+}
+
+char *ceph_osdmap_state_str(char *str, int len, u32 state)
+{
+	if (!len)
+		return str;
+
+	if ((state & CEPH_OSD_EXISTS) && (state & CEPH_OSD_UP))
+		snprintf(str, len, "exists, up");
+	else if (state & CEPH_OSD_EXISTS)
+		snprintf(str, len, "exists");
+	else if (state & CEPH_OSD_UP)
+		snprintf(str, len, "up");
+	else
+		snprintf(str, len, "doesn't exist");
+
+	return str;
+}
+
+/* maps */
+
+static int calc_bits_of(unsigned int t)
+{
+	int b = 0;
+	while (t) {
+		t = t >> 1;
+		b++;
+	}
+	return b;
+}
+
+/*
+ * the foo_mask is the smallest value 2^n-1 that is >= foo.
+ */
+static void calc_pg_masks(struct ceph_pg_pool_info *pi)
+{
+	pi->pg_num_mask = (1 << calc_bits_of(pi->pg_num-1)) - 1;
+	pi->pgp_num_mask = (1 << calc_bits_of(pi->pgp_num-1)) - 1;
+}
+
+/*
+ * decode crush map
+ */
+static int crush_decode_uniform_bucket(void **p, void *end,
+				       struct crush_bucket_uniform *b)
+{
+	dout("crush_decode_uniform_bucket %p to %p\n", *p, end);
+	ceph_decode_need(p, end, (1+b->h.size) * sizeof(u32), bad);
+	b->item_weight = ceph_decode_32(p);
+	return 0;
+bad:
+	return -EINVAL;
+}
+
+static int crush_decode_list_bucket(void **p, void *end,
+				    struct crush_bucket_list *b)
+{
+	int j;
+	dout("crush_decode_list_bucket %p to %p\n", *p, end);
+	b->item_weights = kcalloc(b->h.size, sizeof(u32), GFP_NOFS);
+	if (b->item_weights == NULL)
+		return -ENOMEM;
+	b->sum_weights = kcalloc(b->h.size, sizeof(u32), GFP_NOFS);
+	if (b->sum_weights == NULL)
+		return -ENOMEM;
+	ceph_decode_need(p, end, 2 * b->h.size * sizeof(u32), bad);
+	for (j = 0; j < b->h.size; j++) {
+		b->item_weights[j] = ceph_decode_32(p);
+		b->sum_weights[j] = ceph_decode_32(p);
+	}
+	return 0;
+bad:
+	return -EINVAL;
+}
+
+static int crush_decode_tree_bucket(void **p, void *end,
+				    struct crush_bucket_tree *b)
+{
+	int j;
+	dout("crush_decode_tree_bucket %p to %p\n", *p, end);
+	ceph_decode_8_safe(p, end, b->num_nodes, bad);
+	b->node_weights = kcalloc(b->num_nodes, sizeof(u32), GFP_NOFS);
+	if (b->node_weights == NULL)
+		return -ENOMEM;
+	ceph_decode_need(p, end, b->num_nodes * sizeof(u32), bad);
+	for (j = 0; j < b->num_nodes; j++)
+		b->node_weights[j] = ceph_decode_32(p);
+	return 0;
+bad:
+	return -EINVAL;
+}
+
+static int crush_decode_straw_bucket(void **p, void *end,
+				     struct crush_bucket_straw *b)
+{
+	int j;
+	dout("crush_decode_straw_bucket %p to %p\n", *p, end);
+	b->item_weights = kcalloc(b->h.size, sizeof(u32), GFP_NOFS);
+	if (b->item_weights == NULL)
+		return -ENOMEM;
+	b->straws = kcalloc(b->h.size, sizeof(u32), GFP_NOFS);
+	if (b->straws == NULL)
+		return -ENOMEM;
+	ceph_decode_need(p, end, 2 * b->h.size * sizeof(u32), bad);
+	for (j = 0; j < b->h.size; j++) {
+		b->item_weights[j] = ceph_decode_32(p);
+		b->straws[j] = ceph_decode_32(p);
+	}
+	return 0;
+bad:
+	return -EINVAL;
+}
+
+static int crush_decode_straw2_bucket(void **p, void *end,
+				      struct crush_bucket_straw2 *b)
+{
+	int j;
+	dout("crush_decode_straw2_bucket %p to %p\n", *p, end);
+	b->item_weights = kcalloc(b->h.size, sizeof(u32), GFP_NOFS);
+	if (b->item_weights == NULL)
+		return -ENOMEM;
+	ceph_decode_need(p, end, b->h.size * sizeof(u32), bad);
+	for (j = 0; j < b->h.size; j++)
+		b->item_weights[j] = ceph_decode_32(p);
+	return 0;
+bad:
+	return -EINVAL;
+}
+
+struct crush_name_node {
+	struct rb_node cn_node;
+	int cn_id;
+	char cn_name[];
+};
+
+static struct crush_name_node *alloc_crush_name(size_t name_len)
+{
+	struct crush_name_node *cn;
+
+	cn = kmalloc(sizeof(*cn) + name_len + 1, GFP_NOIO);
+	if (!cn)
+		return NULL;
+
+	RB_CLEAR_NODE(&cn->cn_node);
+	return cn;
+}
+
+static void free_crush_name(struct crush_name_node *cn)
+{
+	WARN_ON(!RB_EMPTY_NODE(&cn->cn_node));
+
+	kfree(cn);
+}
+
+DEFINE_RB_FUNCS(crush_name, struct crush_name_node, cn_id, cn_node)
+
+static int decode_crush_names(void **p, void *end, struct rb_root *root)
+{
+	u32 n;
+
+	ceph_decode_32_safe(p, end, n, e_inval);
+	while (n--) {
+		struct crush_name_node *cn;
+		int id;
+		u32 name_len;
+
+		ceph_decode_32_safe(p, end, id, e_inval);
+		ceph_decode_32_safe(p, end, name_len, e_inval);
+		ceph_decode_need(p, end, name_len, e_inval);
+
+		cn = alloc_crush_name(name_len);
+		if (!cn)
+			return -ENOMEM;
+
+		cn->cn_id = id;
+		memcpy(cn->cn_name, *p, name_len);
+		cn->cn_name[name_len] = '\0';
+		*p += name_len;
+
+		if (!__insert_crush_name(root, cn)) {
+			free_crush_name(cn);
+			return -EEXIST;
+		}
+	}
+
+	return 0;
+
+e_inval:
+	return -EINVAL;
+}
+
+void clear_crush_names(struct rb_root *root)
+{
+	while (!RB_EMPTY_ROOT(root)) {
+		struct crush_name_node *cn =
+		    rb_entry(rb_first(root), struct crush_name_node, cn_node);
+
+		erase_crush_name(root, cn);
+		free_crush_name(cn);
+	}
+}
+
+static struct crush_choose_arg_map *alloc_choose_arg_map(void)
+{
+	struct crush_choose_arg_map *arg_map;
+
+	arg_map = kzalloc(sizeof(*arg_map), GFP_NOIO);
+	if (!arg_map)
+		return NULL;
+
+	RB_CLEAR_NODE(&arg_map->node);
+	return arg_map;
+}
+
+static void free_choose_arg_map(struct crush_choose_arg_map *arg_map)
+{
+	if (arg_map) {
+		int i, j;
+
+		WARN_ON(!RB_EMPTY_NODE(&arg_map->node));
+
+		for (i = 0; i < arg_map->size; i++) {
+			struct crush_choose_arg *arg = &arg_map->args[i];
+
+			for (j = 0; j < arg->weight_set_size; j++)
+				kfree(arg->weight_set[j].weights);
+			kfree(arg->weight_set);
+			kfree(arg->ids);
+		}
+		kfree(arg_map->args);
+		kfree(arg_map);
+	}
+}
+
+DEFINE_RB_FUNCS(choose_arg_map, struct crush_choose_arg_map, choose_args_index,
+		node);
+
+void clear_choose_args(struct crush_map *c)
+{
+	while (!RB_EMPTY_ROOT(&c->choose_args)) {
+		struct crush_choose_arg_map *arg_map =
+		    rb_entry(rb_first(&c->choose_args),
+			     struct crush_choose_arg_map, node);
+
+		erase_choose_arg_map(&c->choose_args, arg_map);
+		free_choose_arg_map(arg_map);
+	}
+}
+
+static u32 *decode_array_32_alloc(void **p, void *end, u32 *plen)
+{
+	u32 *a = NULL;
+	u32 len;
+	int ret;
+
+	ceph_decode_32_safe(p, end, len, e_inval);
+	if (len) {
+		u32 i;
+
+		a = kmalloc_array(len, sizeof(u32), GFP_NOIO);
+		if (!a) {
+			ret = -ENOMEM;
+			goto fail;
+		}
+
+		ceph_decode_need(p, end, len * sizeof(u32), e_inval);
+		for (i = 0; i < len; i++)
+			a[i] = ceph_decode_32(p);
+	}
+
+	*plen = len;
+	return a;
+
+e_inval:
+	ret = -EINVAL;
+fail:
+	kfree(a);
+	return ERR_PTR(ret);
+}
+
+/*
+ * Assumes @arg is zero-initialized.
+ */
+static int decode_choose_arg(void **p, void *end, struct crush_choose_arg *arg)
+{
+	int ret;
+
+	ceph_decode_32_safe(p, end, arg->weight_set_size, e_inval);
+	if (arg->weight_set_size) {
+		u32 i;
+
+		arg->weight_set = kmalloc_array(arg->weight_set_size,
+						sizeof(*arg->weight_set),
+						GFP_NOIO);
+		if (!arg->weight_set)
+			return -ENOMEM;
+
+		for (i = 0; i < arg->weight_set_size; i++) {
+			struct crush_weight_set *w = &arg->weight_set[i];
+
+			w->weights = decode_array_32_alloc(p, end, &w->size);
+			if (IS_ERR(w->weights)) {
+				ret = PTR_ERR(w->weights);
+				w->weights = NULL;
+				return ret;
+			}
+		}
+	}
+
+	arg->ids = decode_array_32_alloc(p, end, &arg->ids_size);
+	if (IS_ERR(arg->ids)) {
+		ret = PTR_ERR(arg->ids);
+		arg->ids = NULL;
+		return ret;
+	}
+
+	return 0;
+
+e_inval:
+	return -EINVAL;
+}
+
+static int decode_choose_args(void **p, void *end, struct crush_map *c)
+{
+	struct crush_choose_arg_map *arg_map = NULL;
+	u32 num_choose_arg_maps, num_buckets;
+	int ret;
+
+	ceph_decode_32_safe(p, end, num_choose_arg_maps, e_inval);
+	while (num_choose_arg_maps--) {
+		arg_map = alloc_choose_arg_map();
+		if (!arg_map) {
+			ret = -ENOMEM;
+			goto fail;
+		}
+
+		ceph_decode_64_safe(p, end, arg_map->choose_args_index,
+				    e_inval);
+		arg_map->size = c->max_buckets;
+		arg_map->args = kcalloc(arg_map->size, sizeof(*arg_map->args),
+					GFP_NOIO);
+		if (!arg_map->args) {
+			ret = -ENOMEM;
+			goto fail;
+		}
+
+		ceph_decode_32_safe(p, end, num_buckets, e_inval);
+		while (num_buckets--) {
+			struct crush_choose_arg *arg;
+			u32 bucket_index;
+
+			ceph_decode_32_safe(p, end, bucket_index, e_inval);
+			if (bucket_index >= arg_map->size)
+				goto e_inval;
+
+			arg = &arg_map->args[bucket_index];
+			ret = decode_choose_arg(p, end, arg);
+			if (ret)
+				goto fail;
+
+			if (arg->ids_size &&
+			    arg->ids_size != c->buckets[bucket_index]->size)
+				goto e_inval;
+		}
+
+		insert_choose_arg_map(&c->choose_args, arg_map);
+	}
+
+	return 0;
+
+e_inval:
+	ret = -EINVAL;
+fail:
+	free_choose_arg_map(arg_map);
+	return ret;
+}
+
+static void crush_finalize(struct crush_map *c)
+{
+	__s32 b;
+
+	/* Space for the array of pointers to per-bucket workspace */
+	c->working_size = sizeof(struct crush_work) +
+	    c->max_buckets * sizeof(struct crush_work_bucket *);
+
+	for (b = 0; b < c->max_buckets; b++) {
+		if (!c->buckets[b])
+			continue;
+
+		switch (c->buckets[b]->alg) {
+		default:
+			/*
+			 * The base case, permutation variables and
+			 * the pointer to the permutation array.
+			 */
+			c->working_size += sizeof(struct crush_work_bucket);
+			break;
+		}
+		/* Every bucket has a permutation array. */
+		c->working_size += c->buckets[b]->size * sizeof(__u32);
+	}
+}
+
+static struct crush_map *crush_decode(void *pbyval, void *end)
+{
+	struct crush_map *c;
+	int err;
+	int i, j;
+	void **p = &pbyval;
+	void *start = pbyval;
+	u32 magic;
+
+	dout("crush_decode %p to %p len %d\n", *p, end, (int)(end - *p));
+
+	c = kzalloc(sizeof(*c), GFP_NOFS);
+	if (c == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	c->type_names = RB_ROOT;
+	c->names = RB_ROOT;
+	c->choose_args = RB_ROOT;
+
+        /* set tunables to default values */
+        c->choose_local_tries = 2;
+        c->choose_local_fallback_tries = 5;
+        c->choose_total_tries = 19;
+	c->chooseleaf_descend_once = 0;
+
+	ceph_decode_need(p, end, 4*sizeof(u32), bad);
+	magic = ceph_decode_32(p);
+	if (magic != CRUSH_MAGIC) {
+		pr_err("crush_decode magic %x != current %x\n",
+		       (unsigned int)magic, (unsigned int)CRUSH_MAGIC);
+		goto bad;
+	}
+	c->max_buckets = ceph_decode_32(p);
+	c->max_rules = ceph_decode_32(p);
+	c->max_devices = ceph_decode_32(p);
+
+	c->buckets = kcalloc(c->max_buckets, sizeof(*c->buckets), GFP_NOFS);
+	if (c->buckets == NULL)
+		goto badmem;
+	c->rules = kcalloc(c->max_rules, sizeof(*c->rules), GFP_NOFS);
+	if (c->rules == NULL)
+		goto badmem;
+
+	/* buckets */
+	for (i = 0; i < c->max_buckets; i++) {
+		int size = 0;
+		u32 alg;
+		struct crush_bucket *b;
+
+		ceph_decode_32_safe(p, end, alg, bad);
+		if (alg == 0) {
+			c->buckets[i] = NULL;
+			continue;
+		}
+		dout("crush_decode bucket %d off %x %p to %p\n",
+		     i, (int)(*p-start), *p, end);
+
+		switch (alg) {
+		case CRUSH_BUCKET_UNIFORM:
+			size = sizeof(struct crush_bucket_uniform);
+			break;
+		case CRUSH_BUCKET_LIST:
+			size = sizeof(struct crush_bucket_list);
+			break;
+		case CRUSH_BUCKET_TREE:
+			size = sizeof(struct crush_bucket_tree);
+			break;
+		case CRUSH_BUCKET_STRAW:
+			size = sizeof(struct crush_bucket_straw);
+			break;
+		case CRUSH_BUCKET_STRAW2:
+			size = sizeof(struct crush_bucket_straw2);
+			break;
+		default:
+			goto bad;
+		}
+		BUG_ON(size == 0);
+		b = c->buckets[i] = kzalloc(size, GFP_NOFS);
+		if (b == NULL)
+			goto badmem;
+
+		ceph_decode_need(p, end, 4*sizeof(u32), bad);
+		b->id = ceph_decode_32(p);
+		b->type = ceph_decode_16(p);
+		b->alg = ceph_decode_8(p);
+		b->hash = ceph_decode_8(p);
+		b->weight = ceph_decode_32(p);
+		b->size = ceph_decode_32(p);
+
+		dout("crush_decode bucket size %d off %x %p to %p\n",
+		     b->size, (int)(*p-start), *p, end);
+
+		b->items = kcalloc(b->size, sizeof(__s32), GFP_NOFS);
+		if (b->items == NULL)
+			goto badmem;
+
+		ceph_decode_need(p, end, b->size*sizeof(u32), bad);
+		for (j = 0; j < b->size; j++)
+			b->items[j] = ceph_decode_32(p);
+
+		switch (b->alg) {
+		case CRUSH_BUCKET_UNIFORM:
+			err = crush_decode_uniform_bucket(p, end,
+				  (struct crush_bucket_uniform *)b);
+			if (err < 0)
+				goto fail;
+			break;
+		case CRUSH_BUCKET_LIST:
+			err = crush_decode_list_bucket(p, end,
+			       (struct crush_bucket_list *)b);
+			if (err < 0)
+				goto fail;
+			break;
+		case CRUSH_BUCKET_TREE:
+			err = crush_decode_tree_bucket(p, end,
+				(struct crush_bucket_tree *)b);
+			if (err < 0)
+				goto fail;
+			break;
+		case CRUSH_BUCKET_STRAW:
+			err = crush_decode_straw_bucket(p, end,
+				(struct crush_bucket_straw *)b);
+			if (err < 0)
+				goto fail;
+			break;
+		case CRUSH_BUCKET_STRAW2:
+			err = crush_decode_straw2_bucket(p, end,
+				(struct crush_bucket_straw2 *)b);
+			if (err < 0)
+				goto fail;
+			break;
+		}
+	}
+
+	/* rules */
+	dout("rule vec is %p\n", c->rules);
+	for (i = 0; i < c->max_rules; i++) {
+		u32 yes;
+		struct crush_rule *r;
+
+		ceph_decode_32_safe(p, end, yes, bad);
+		if (!yes) {
+			dout("crush_decode NO rule %d off %x %p to %p\n",
+			     i, (int)(*p-start), *p, end);
+			c->rules[i] = NULL;
+			continue;
+		}
+
+		dout("crush_decode rule %d off %x %p to %p\n",
+		     i, (int)(*p-start), *p, end);
+
+		/* len */
+		ceph_decode_32_safe(p, end, yes, bad);
+#if BITS_PER_LONG == 32
+		if (yes > (ULONG_MAX - sizeof(*r))
+			  / sizeof(struct crush_rule_step))
+			goto bad;
+#endif
+		r = kmalloc(struct_size(r, steps, yes), GFP_NOFS);
+		if (r == NULL)
+			goto badmem;
+		dout(" rule %d is at %p\n", i, r);
+		c->rules[i] = r;
+		r->len = yes;
+		ceph_decode_copy_safe(p, end, &r->mask, 4, bad); /* 4 u8's */
+		ceph_decode_need(p, end, r->len*3*sizeof(u32), bad);
+		for (j = 0; j < r->len; j++) {
+			r->steps[j].op = ceph_decode_32(p);
+			r->steps[j].arg1 = ceph_decode_32(p);
+			r->steps[j].arg2 = ceph_decode_32(p);
+		}
+	}
+
+	err = decode_crush_names(p, end, &c->type_names);
+	if (err)
+		goto fail;
+
+	err = decode_crush_names(p, end, &c->names);
+	if (err)
+		goto fail;
+
+	ceph_decode_skip_map(p, end, 32, string, bad); /* rule_name_map */
+
+        /* tunables */
+        ceph_decode_need(p, end, 3*sizeof(u32), done);
+        c->choose_local_tries = ceph_decode_32(p);
+        c->choose_local_fallback_tries =  ceph_decode_32(p);
+        c->choose_total_tries = ceph_decode_32(p);
+        dout("crush decode tunable choose_local_tries = %d\n",
+             c->choose_local_tries);
+        dout("crush decode tunable choose_local_fallback_tries = %d\n",
+             c->choose_local_fallback_tries);
+        dout("crush decode tunable choose_total_tries = %d\n",
+             c->choose_total_tries);
+
+	ceph_decode_need(p, end, sizeof(u32), done);
+	c->chooseleaf_descend_once = ceph_decode_32(p);
+	dout("crush decode tunable chooseleaf_descend_once = %d\n",
+	     c->chooseleaf_descend_once);
+
+	ceph_decode_need(p, end, sizeof(u8), done);
+	c->chooseleaf_vary_r = ceph_decode_8(p);
+	dout("crush decode tunable chooseleaf_vary_r = %d\n",
+	     c->chooseleaf_vary_r);
+
+	/* skip straw_calc_version, allowed_bucket_algs */
+	ceph_decode_need(p, end, sizeof(u8) + sizeof(u32), done);
+	*p += sizeof(u8) + sizeof(u32);
+
+	ceph_decode_need(p, end, sizeof(u8), done);
+	c->chooseleaf_stable = ceph_decode_8(p);
+	dout("crush decode tunable chooseleaf_stable = %d\n",
+	     c->chooseleaf_stable);
+
+	if (*p != end) {
+		/* class_map */
+		ceph_decode_skip_map(p, end, 32, 32, bad);
+		/* class_name */
+		ceph_decode_skip_map(p, end, 32, string, bad);
+		/* class_bucket */
+		ceph_decode_skip_map_of_map(p, end, 32, 32, 32, bad);
+	}
+
+	if (*p != end) {
+		err = decode_choose_args(p, end, c);
+		if (err)
+			goto fail;
+	}
+
+done:
+	crush_finalize(c);
+	dout("crush_decode success\n");
+	return c;
+
+badmem:
+	err = -ENOMEM;
+fail:
+	dout("crush_decode fail %d\n", err);
+	crush_destroy(c);
+	return ERR_PTR(err);
+
+bad:
+	err = -EINVAL;
+	goto fail;
+}
+
+int ceph_pg_compare(const struct ceph_pg *lhs, const struct ceph_pg *rhs)
+{
+	if (lhs->pool < rhs->pool)
+		return -1;
+	if (lhs->pool > rhs->pool)
+		return 1;
+	if (lhs->seed < rhs->seed)
+		return -1;
+	if (lhs->seed > rhs->seed)
+		return 1;
+
+	return 0;
+}
+
+int ceph_spg_compare(const struct ceph_spg *lhs, const struct ceph_spg *rhs)
+{
+	int ret;
+
+	ret = ceph_pg_compare(&lhs->pgid, &rhs->pgid);
+	if (ret)
+		return ret;
+
+	if (lhs->shard < rhs->shard)
+		return -1;
+	if (lhs->shard > rhs->shard)
+		return 1;
+
+	return 0;
+}
+
+static struct ceph_pg_mapping *alloc_pg_mapping(size_t payload_len)
+{
+	struct ceph_pg_mapping *pg;
+
+	pg = kmalloc(sizeof(*pg) + payload_len, GFP_NOIO);
+	if (!pg)
+		return NULL;
+
+	RB_CLEAR_NODE(&pg->node);
+	return pg;
+}
+
+static void free_pg_mapping(struct ceph_pg_mapping *pg)
+{
+	WARN_ON(!RB_EMPTY_NODE(&pg->node));
+
+	kfree(pg);
+}
+
+/*
+ * rbtree of pg_mapping for handling pg_temp (explicit mapping of pgid
+ * to a set of osds) and primary_temp (explicit primary setting)
+ */
+DEFINE_RB_FUNCS2(pg_mapping, struct ceph_pg_mapping, pgid, ceph_pg_compare,
+		 RB_BYPTR, const struct ceph_pg *, node)
+
+/*
+ * rbtree of pg pool info
+ */
+DEFINE_RB_FUNCS(pg_pool, struct ceph_pg_pool_info, id, node)
+
+struct ceph_pg_pool_info *ceph_pg_pool_by_id(struct ceph_osdmap *map, u64 id)
+{
+	return lookup_pg_pool(&map->pg_pools, id);
+}
+
+const char *ceph_pg_pool_name_by_id(struct ceph_osdmap *map, u64 id)
+{
+	struct ceph_pg_pool_info *pi;
+
+	if (id == CEPH_NOPOOL)
+		return NULL;
+
+	if (WARN_ON_ONCE(id > (u64) INT_MAX))
+		return NULL;
+
+	pi = lookup_pg_pool(&map->pg_pools, id);
+	return pi ? pi->name : NULL;
+}
+EXPORT_SYMBOL(ceph_pg_pool_name_by_id);
+
+int ceph_pg_poolid_by_name(struct ceph_osdmap *map, const char *name)
+{
+	struct rb_node *rbp;
+
+	for (rbp = rb_first(&map->pg_pools); rbp; rbp = rb_next(rbp)) {
+		struct ceph_pg_pool_info *pi =
+			rb_entry(rbp, struct ceph_pg_pool_info, node);
+		if (pi->name && strcmp(pi->name, name) == 0)
+			return pi->id;
+	}
+	return -ENOENT;
+}
+EXPORT_SYMBOL(ceph_pg_poolid_by_name);
+
+u64 ceph_pg_pool_flags(struct ceph_osdmap *map, u64 id)
+{
+	struct ceph_pg_pool_info *pi;
+
+	pi = lookup_pg_pool(&map->pg_pools, id);
+	return pi ? pi->flags : 0;
+}
+EXPORT_SYMBOL(ceph_pg_pool_flags);
+
+static void __remove_pg_pool(struct rb_root *root, struct ceph_pg_pool_info *pi)
+{
+	erase_pg_pool(root, pi);
+	kfree(pi->name);
+	kfree(pi);
+}
+
+static int decode_pool(void **p, void *end, struct ceph_pg_pool_info *pi)
+{
+	u8 ev, cv;
+	unsigned len, num;
+	void *pool_end;
+
+	ceph_decode_need(p, end, 2 + 4, bad);
+	ev = ceph_decode_8(p);  /* encoding version */
+	cv = ceph_decode_8(p); /* compat version */
+	if (ev < 5) {
+		pr_warn("got v %d < 5 cv %d of ceph_pg_pool\n", ev, cv);
+		return -EINVAL;
+	}
+	if (cv > 9) {
+		pr_warn("got v %d cv %d > 9 of ceph_pg_pool\n", ev, cv);
+		return -EINVAL;
+	}
+	len = ceph_decode_32(p);
+	ceph_decode_need(p, end, len, bad);
+	pool_end = *p + len;
+
+	pi->type = ceph_decode_8(p);
+	pi->size = ceph_decode_8(p);
+	pi->crush_ruleset = ceph_decode_8(p);
+	pi->object_hash = ceph_decode_8(p);
+
+	pi->pg_num = ceph_decode_32(p);
+	pi->pgp_num = ceph_decode_32(p);
+
+	*p += 4 + 4;  /* skip lpg* */
+	*p += 4;      /* skip last_change */
+	*p += 8 + 4;  /* skip snap_seq, snap_epoch */
+
+	/* skip snaps */
+	num = ceph_decode_32(p);
+	while (num--) {
+		*p += 8;  /* snapid key */
+		*p += 1 + 1; /* versions */
+		len = ceph_decode_32(p);
+		*p += len;
+	}
+
+	/* skip removed_snaps */
+	num = ceph_decode_32(p);
+	*p += num * (8 + 8);
+
+	*p += 8;  /* skip auid */
+	pi->flags = ceph_decode_64(p);
+	*p += 4;  /* skip crash_replay_interval */
+
+	if (ev >= 7)
+		pi->min_size = ceph_decode_8(p);
+	else
+		pi->min_size = pi->size - pi->size / 2;
+
+	if (ev >= 8)
+		*p += 8 + 8;  /* skip quota_max_* */
+
+	if (ev >= 9) {
+		/* skip tiers */
+		num = ceph_decode_32(p);
+		*p += num * 8;
+
+		*p += 8;  /* skip tier_of */
+		*p += 1;  /* skip cache_mode */
+
+		pi->read_tier = ceph_decode_64(p);
+		pi->write_tier = ceph_decode_64(p);
+	} else {
+		pi->read_tier = -1;
+		pi->write_tier = -1;
+	}
+
+	if (ev >= 10) {
+		/* skip properties */
+		num = ceph_decode_32(p);
+		while (num--) {
+			len = ceph_decode_32(p);
+			*p += len; /* key */
+			len = ceph_decode_32(p);
+			*p += len; /* val */
+		}
+	}
+
+	if (ev >= 11) {
+		/* skip hit_set_params */
+		*p += 1 + 1; /* versions */
+		len = ceph_decode_32(p);
+		*p += len;
+
+		*p += 4; /* skip hit_set_period */
+		*p += 4; /* skip hit_set_count */
+	}
+
+	if (ev >= 12)
+		*p += 4; /* skip stripe_width */
+
+	if (ev >= 13) {
+		*p += 8; /* skip target_max_bytes */
+		*p += 8; /* skip target_max_objects */
+		*p += 4; /* skip cache_target_dirty_ratio_micro */
+		*p += 4; /* skip cache_target_full_ratio_micro */
+		*p += 4; /* skip cache_min_flush_age */
+		*p += 4; /* skip cache_min_evict_age */
+	}
+
+	if (ev >=  14) {
+		/* skip erasure_code_profile */
+		len = ceph_decode_32(p);
+		*p += len;
+	}
+
+	/*
+	 * last_force_op_resend_preluminous, will be overridden if the
+	 * map was encoded with RESEND_ON_SPLIT
+	 */
+	if (ev >= 15)
+		pi->last_force_request_resend = ceph_decode_32(p);
+	else
+		pi->last_force_request_resend = 0;
+
+	if (ev >= 16)
+		*p += 4; /* skip min_read_recency_for_promote */
+
+	if (ev >= 17)
+		*p += 8; /* skip expected_num_objects */
+
+	if (ev >= 19)
+		*p += 4; /* skip cache_target_dirty_high_ratio_micro */
+
+	if (ev >= 20)
+		*p += 4; /* skip min_write_recency_for_promote */
+
+	if (ev >= 21)
+		*p += 1; /* skip use_gmt_hitset */
+
+	if (ev >= 22)
+		*p += 1; /* skip fast_read */
+
+	if (ev >= 23) {
+		*p += 4; /* skip hit_set_grade_decay_rate */
+		*p += 4; /* skip hit_set_search_last_n */
+	}
+
+	if (ev >= 24) {
+		/* skip opts */
+		*p += 1 + 1; /* versions */
+		len = ceph_decode_32(p);
+		*p += len;
+	}
+
+	if (ev >= 25)
+		pi->last_force_request_resend = ceph_decode_32(p);
+
+	/* ignore the rest */
+
+	*p = pool_end;
+	calc_pg_masks(pi);
+	return 0;
+
+bad:
+	return -EINVAL;
+}
+
+static int decode_pool_names(void **p, void *end, struct ceph_osdmap *map)
+{
+	struct ceph_pg_pool_info *pi;
+	u32 num, len;
+	u64 pool;
+
+	ceph_decode_32_safe(p, end, num, bad);
+	dout(" %d pool names\n", num);
+	while (num--) {
+		ceph_decode_64_safe(p, end, pool, bad);
+		ceph_decode_32_safe(p, end, len, bad);
+		dout("  pool %llu len %d\n", pool, len);
+		ceph_decode_need(p, end, len, bad);
+		pi = lookup_pg_pool(&map->pg_pools, pool);
+		if (pi) {
+			char *name = kstrndup(*p, len, GFP_NOFS);
+
+			if (!name)
+				return -ENOMEM;
+			kfree(pi->name);
+			pi->name = name;
+			dout("  name is %s\n", pi->name);
+		}
+		*p += len;
+	}
+	return 0;
+
+bad:
+	return -EINVAL;
+}
+
+/*
+ * CRUSH workspaces
+ *
+ * workspace_manager framework borrowed from fs/btrfs/compression.c.
+ * Two simplifications: there is only one type of workspace and there
+ * is always at least one workspace.
+ */
+static struct crush_work *alloc_workspace(const struct crush_map *c)
+{
+	struct crush_work *work;
+	size_t work_size;
+
+	WARN_ON(!c->working_size);
+	work_size = crush_work_size(c, CEPH_PG_MAX_SIZE);
+	dout("%s work_size %zu bytes\n", __func__, work_size);
+
+	work = kvmalloc(work_size, GFP_NOIO);
+	if (!work)
+		return NULL;
+
+	INIT_LIST_HEAD(&work->item);
+	crush_init_workspace(c, work);
+	return work;
+}
+
+static void free_workspace(struct crush_work *work)
+{
+	WARN_ON(!list_empty(&work->item));
+	kvfree(work);
+}
+
+static void init_workspace_manager(struct workspace_manager *wsm)
+{
+	INIT_LIST_HEAD(&wsm->idle_ws);
+	spin_lock_init(&wsm->ws_lock);
+	atomic_set(&wsm->total_ws, 0);
+	wsm->free_ws = 0;
+	init_waitqueue_head(&wsm->ws_wait);
+}
+
+static void add_initial_workspace(struct workspace_manager *wsm,
+				  struct crush_work *work)
+{
+	WARN_ON(!list_empty(&wsm->idle_ws));
+
+	list_add(&work->item, &wsm->idle_ws);
+	atomic_set(&wsm->total_ws, 1);
+	wsm->free_ws = 1;
+}
+
+static void cleanup_workspace_manager(struct workspace_manager *wsm)
+{
+	struct crush_work *work;
+
+	while (!list_empty(&wsm->idle_ws)) {
+		work = list_first_entry(&wsm->idle_ws, struct crush_work,
+					item);
+		list_del_init(&work->item);
+		free_workspace(work);
+	}
+	atomic_set(&wsm->total_ws, 0);
+	wsm->free_ws = 0;
+}
+
+/*
+ * Finds an available workspace or allocates a new one.  If it's not
+ * possible to allocate a new one, waits until there is one.
+ */
+static struct crush_work *get_workspace(struct workspace_manager *wsm,
+					const struct crush_map *c)
+{
+	struct crush_work *work;
+	int cpus = num_online_cpus();
+
+again:
+	spin_lock(&wsm->ws_lock);
+	if (!list_empty(&wsm->idle_ws)) {
+		work = list_first_entry(&wsm->idle_ws, struct crush_work,
+					item);
+		list_del_init(&work->item);
+		wsm->free_ws--;
+		spin_unlock(&wsm->ws_lock);
+		return work;
+
+	}
+	if (atomic_read(&wsm->total_ws) > cpus) {
+		DEFINE_WAIT(wait);
+
+		spin_unlock(&wsm->ws_lock);
+		prepare_to_wait(&wsm->ws_wait, &wait, TASK_UNINTERRUPTIBLE);
+		if (atomic_read(&wsm->total_ws) > cpus && !wsm->free_ws)
+			schedule();
+		finish_wait(&wsm->ws_wait, &wait);
+		goto again;
+	}
+	atomic_inc(&wsm->total_ws);
+	spin_unlock(&wsm->ws_lock);
+
+	work = alloc_workspace(c);
+	if (!work) {
+		atomic_dec(&wsm->total_ws);
+		wake_up(&wsm->ws_wait);
+
+		/*
+		 * Do not return the error but go back to waiting.  We
+		 * have the initial workspace and the CRUSH computation
+		 * time is bounded so we will get it eventually.
+		 */
+		WARN_ON(atomic_read(&wsm->total_ws) < 1);
+		goto again;
+	}
+	return work;
+}
+
+/*
+ * Puts a workspace back on the list or frees it if we have enough
+ * idle ones sitting around.
+ */
+static void put_workspace(struct workspace_manager *wsm,
+			  struct crush_work *work)
+{
+	spin_lock(&wsm->ws_lock);
+	if (wsm->free_ws <= num_online_cpus()) {
+		list_add(&work->item, &wsm->idle_ws);
+		wsm->free_ws++;
+		spin_unlock(&wsm->ws_lock);
+		goto wake;
+	}
+	spin_unlock(&wsm->ws_lock);
+
+	free_workspace(work);
+	atomic_dec(&wsm->total_ws);
+wake:
+	if (wq_has_sleeper(&wsm->ws_wait))
+		wake_up(&wsm->ws_wait);
+}
+
+/*
+ * osd map
+ */
+struct ceph_osdmap *ceph_osdmap_alloc(void)
+{
+	struct ceph_osdmap *map;
+
+	map = kzalloc(sizeof(*map), GFP_NOIO);
+	if (!map)
+		return NULL;
+
+	map->pg_pools = RB_ROOT;
+	map->pool_max = -1;
+	map->pg_temp = RB_ROOT;
+	map->primary_temp = RB_ROOT;
+	map->pg_upmap = RB_ROOT;
+	map->pg_upmap_items = RB_ROOT;
+
+	init_workspace_manager(&map->crush_wsm);
+
+	return map;
+}
+
+void ceph_osdmap_destroy(struct ceph_osdmap *map)
+{
+	dout("osdmap_destroy %p\n", map);
+
+	if (map->crush)
+		crush_destroy(map->crush);
+	cleanup_workspace_manager(&map->crush_wsm);
+
+	while (!RB_EMPTY_ROOT(&map->pg_temp)) {
+		struct ceph_pg_mapping *pg =
+			rb_entry(rb_first(&map->pg_temp),
+				 struct ceph_pg_mapping, node);
+		erase_pg_mapping(&map->pg_temp, pg);
+		free_pg_mapping(pg);
+	}
+	while (!RB_EMPTY_ROOT(&map->primary_temp)) {
+		struct ceph_pg_mapping *pg =
+			rb_entry(rb_first(&map->primary_temp),
+				 struct ceph_pg_mapping, node);
+		erase_pg_mapping(&map->primary_temp, pg);
+		free_pg_mapping(pg);
+	}
+	while (!RB_EMPTY_ROOT(&map->pg_upmap)) {
+		struct ceph_pg_mapping *pg =
+			rb_entry(rb_first(&map->pg_upmap),
+				 struct ceph_pg_mapping, node);
+		rb_erase(&pg->node, &map->pg_upmap);
+		kfree(pg);
+	}
+	while (!RB_EMPTY_ROOT(&map->pg_upmap_items)) {
+		struct ceph_pg_mapping *pg =
+			rb_entry(rb_first(&map->pg_upmap_items),
+				 struct ceph_pg_mapping, node);
+		rb_erase(&pg->node, &map->pg_upmap_items);
+		kfree(pg);
+	}
+	while (!RB_EMPTY_ROOT(&map->pg_pools)) {
+		struct ceph_pg_pool_info *pi =
+			rb_entry(rb_first(&map->pg_pools),
+				 struct ceph_pg_pool_info, node);
+		__remove_pg_pool(&map->pg_pools, pi);
+	}
+	kvfree(map->osd_state);
+	kvfree(map->osd_weight);
+	kvfree(map->osd_addr);
+	kvfree(map->osd_primary_affinity);
+	kfree(map);
+}
+
+/*
+ * Adjust max_osd value, (re)allocate arrays.
+ *
+ * The new elements are properly initialized.
+ */
+static int osdmap_set_max_osd(struct ceph_osdmap *map, u32 max)
+{
+	u32 *state;
+	u32 *weight;
+	struct ceph_entity_addr *addr;
+	u32 to_copy;
+	int i;
+
+	dout("%s old %u new %u\n", __func__, map->max_osd, max);
+	if (max == map->max_osd)
+		return 0;
+
+	state = kvmalloc(array_size(max, sizeof(*state)), GFP_NOFS);
+	weight = kvmalloc(array_size(max, sizeof(*weight)), GFP_NOFS);
+	addr = kvmalloc(array_size(max, sizeof(*addr)), GFP_NOFS);
+	if (!state || !weight || !addr) {
+		kvfree(state);
+		kvfree(weight);
+		kvfree(addr);
+		return -ENOMEM;
+	}
+
+	to_copy = min(map->max_osd, max);
+	if (map->osd_state) {
+		memcpy(state, map->osd_state, to_copy * sizeof(*state));
+		memcpy(weight, map->osd_weight, to_copy * sizeof(*weight));
+		memcpy(addr, map->osd_addr, to_copy * sizeof(*addr));
+		kvfree(map->osd_state);
+		kvfree(map->osd_weight);
+		kvfree(map->osd_addr);
+	}
+
+	map->osd_state = state;
+	map->osd_weight = weight;
+	map->osd_addr = addr;
+	for (i = map->max_osd; i < max; i++) {
+		map->osd_state[i] = 0;
+		map->osd_weight[i] = CEPH_OSD_OUT;
+		memset(map->osd_addr + i, 0, sizeof(*map->osd_addr));
+	}
+
+	if (map->osd_primary_affinity) {
+		u32 *affinity;
+
+		affinity = kvmalloc(array_size(max, sizeof(*affinity)),
+					 GFP_NOFS);
+		if (!affinity)
+			return -ENOMEM;
+
+		memcpy(affinity, map->osd_primary_affinity,
+		       to_copy * sizeof(*affinity));
+		kvfree(map->osd_primary_affinity);
+
+		map->osd_primary_affinity = affinity;
+		for (i = map->max_osd; i < max; i++)
+			map->osd_primary_affinity[i] =
+			    CEPH_OSD_DEFAULT_PRIMARY_AFFINITY;
+	}
+
+	map->max_osd = max;
+
+	return 0;
+}
+
+static int osdmap_set_crush(struct ceph_osdmap *map, struct crush_map *crush)
+{
+	struct crush_work *work;
+
+	if (IS_ERR(crush))
+		return PTR_ERR(crush);
+
+	work = alloc_workspace(crush);
+	if (!work) {
+		crush_destroy(crush);
+		return -ENOMEM;
+	}
+
+	if (map->crush)
+		crush_destroy(map->crush);
+	cleanup_workspace_manager(&map->crush_wsm);
+	map->crush = crush;
+	add_initial_workspace(&map->crush_wsm, work);
+	return 0;
+}
+
+#define OSDMAP_WRAPPER_COMPAT_VER	7
+#define OSDMAP_CLIENT_DATA_COMPAT_VER	1
+
+/*
+ * Return 0 or error.  On success, *v is set to 0 for old (v6) osdmaps,
+ * to struct_v of the client_data section for new (v7 and above)
+ * osdmaps.
+ */
+static int get_osdmap_client_data_v(void **p, void *end,
+				    const char *prefix, u8 *v)
+{
+	u8 struct_v;
+
+	ceph_decode_8_safe(p, end, struct_v, e_inval);
+	if (struct_v >= 7) {
+		u8 struct_compat;
+
+		ceph_decode_8_safe(p, end, struct_compat, e_inval);
+		if (struct_compat > OSDMAP_WRAPPER_COMPAT_VER) {
+			pr_warn("got v %d cv %d > %d of %s ceph_osdmap\n",
+				struct_v, struct_compat,
+				OSDMAP_WRAPPER_COMPAT_VER, prefix);
+			return -EINVAL;
+		}
+		*p += 4; /* ignore wrapper struct_len */
+
+		ceph_decode_8_safe(p, end, struct_v, e_inval);
+		ceph_decode_8_safe(p, end, struct_compat, e_inval);
+		if (struct_compat > OSDMAP_CLIENT_DATA_COMPAT_VER) {
+			pr_warn("got v %d cv %d > %d of %s ceph_osdmap client data\n",
+				struct_v, struct_compat,
+				OSDMAP_CLIENT_DATA_COMPAT_VER, prefix);
+			return -EINVAL;
+		}
+		*p += 4; /* ignore client data struct_len */
+	} else {
+		u16 version;
+
+		*p -= 1;
+		ceph_decode_16_safe(p, end, version, e_inval);
+		if (version < 6) {
+			pr_warn("got v %d < 6 of %s ceph_osdmap\n",
+				version, prefix);
+			return -EINVAL;
+		}
+
+		/* old osdmap encoding */
+		struct_v = 0;
+	}
+
+	*v = struct_v;
+	return 0;
+
+e_inval:
+	return -EINVAL;
+}
+
+static int __decode_pools(void **p, void *end, struct ceph_osdmap *map,
+			  bool incremental)
+{
+	u32 n;
+
+	ceph_decode_32_safe(p, end, n, e_inval);
+	while (n--) {
+		struct ceph_pg_pool_info *pi;
+		u64 pool;
+		int ret;
+
+		ceph_decode_64_safe(p, end, pool, e_inval);
+
+		pi = lookup_pg_pool(&map->pg_pools, pool);
+		if (!incremental || !pi) {
+			pi = kzalloc(sizeof(*pi), GFP_NOFS);
+			if (!pi)
+				return -ENOMEM;
+
+			RB_CLEAR_NODE(&pi->node);
+			pi->id = pool;
+
+			if (!__insert_pg_pool(&map->pg_pools, pi)) {
+				kfree(pi);
+				return -EEXIST;
+			}
+		}
+
+		ret = decode_pool(p, end, pi);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+
+e_inval:
+	return -EINVAL;
+}
+
+static int decode_pools(void **p, void *end, struct ceph_osdmap *map)
+{
+	return __decode_pools(p, end, map, false);
+}
+
+static int decode_new_pools(void **p, void *end, struct ceph_osdmap *map)
+{
+	return __decode_pools(p, end, map, true);
+}
+
+typedef struct ceph_pg_mapping *(*decode_mapping_fn_t)(void **, void *, bool);
+
+static int decode_pg_mapping(void **p, void *end, struct rb_root *mapping_root,
+			     decode_mapping_fn_t fn, bool incremental)
+{
+	u32 n;
+
+	WARN_ON(!incremental && !fn);
+
+	ceph_decode_32_safe(p, end, n, e_inval);
+	while (n--) {
+		struct ceph_pg_mapping *pg;
+		struct ceph_pg pgid;
+		int ret;
+
+		ret = ceph_decode_pgid(p, end, &pgid);
+		if (ret)
+			return ret;
+
+		pg = lookup_pg_mapping(mapping_root, &pgid);
+		if (pg) {
+			WARN_ON(!incremental);
+			erase_pg_mapping(mapping_root, pg);
+			free_pg_mapping(pg);
+		}
+
+		if (fn) {
+			pg = fn(p, end, incremental);
+			if (IS_ERR(pg))
+				return PTR_ERR(pg);
+
+			if (pg) {
+				pg->pgid = pgid; /* struct */
+				insert_pg_mapping(mapping_root, pg);
+			}
+		}
+	}
+
+	return 0;
+
+e_inval:
+	return -EINVAL;
+}
+
+static struct ceph_pg_mapping *__decode_pg_temp(void **p, void *end,
+						bool incremental)
+{
+	struct ceph_pg_mapping *pg;
+	u32 len, i;
+
+	ceph_decode_32_safe(p, end, len, e_inval);
+	if (len == 0 && incremental)
+		return NULL;	/* new_pg_temp: [] to remove */
+	if (len > (SIZE_MAX - sizeof(*pg)) / sizeof(u32))
+		return ERR_PTR(-EINVAL);
+
+	ceph_decode_need(p, end, len * sizeof(u32), e_inval);
+	pg = alloc_pg_mapping(len * sizeof(u32));
+	if (!pg)
+		return ERR_PTR(-ENOMEM);
+
+	pg->pg_temp.len = len;
+	for (i = 0; i < len; i++)
+		pg->pg_temp.osds[i] = ceph_decode_32(p);
+
+	return pg;
+
+e_inval:
+	return ERR_PTR(-EINVAL);
+}
+
+static int decode_pg_temp(void **p, void *end, struct ceph_osdmap *map)
+{
+	return decode_pg_mapping(p, end, &map->pg_temp, __decode_pg_temp,
+				 false);
+}
+
+static int decode_new_pg_temp(void **p, void *end, struct ceph_osdmap *map)
+{
+	return decode_pg_mapping(p, end, &map->pg_temp, __decode_pg_temp,
+				 true);
+}
+
+static struct ceph_pg_mapping *__decode_primary_temp(void **p, void *end,
+						     bool incremental)
+{
+	struct ceph_pg_mapping *pg;
+	u32 osd;
+
+	ceph_decode_32_safe(p, end, osd, e_inval);
+	if (osd == (u32)-1 && incremental)
+		return NULL;	/* new_primary_temp: -1 to remove */
+
+	pg = alloc_pg_mapping(0);
+	if (!pg)
+		return ERR_PTR(-ENOMEM);
+
+	pg->primary_temp.osd = osd;
+	return pg;
+
+e_inval:
+	return ERR_PTR(-EINVAL);
+}
+
+static int decode_primary_temp(void **p, void *end, struct ceph_osdmap *map)
+{
+	return decode_pg_mapping(p, end, &map->primary_temp,
+				 __decode_primary_temp, false);
+}
+
+static int decode_new_primary_temp(void **p, void *end,
+				   struct ceph_osdmap *map)
+{
+	return decode_pg_mapping(p, end, &map->primary_temp,
+				 __decode_primary_temp, true);
+}
+
+u32 ceph_get_primary_affinity(struct ceph_osdmap *map, int osd)
+{
+	BUG_ON(osd >= map->max_osd);
+
+	if (!map->osd_primary_affinity)
+		return CEPH_OSD_DEFAULT_PRIMARY_AFFINITY;
+
+	return map->osd_primary_affinity[osd];
+}
+
+static int set_primary_affinity(struct ceph_osdmap *map, int osd, u32 aff)
+{
+	BUG_ON(osd >= map->max_osd);
+
+	if (!map->osd_primary_affinity) {
+		int i;
+
+		map->osd_primary_affinity = kvmalloc(
+		    array_size(map->max_osd, sizeof(*map->osd_primary_affinity)),
+		    GFP_NOFS);
+		if (!map->osd_primary_affinity)
+			return -ENOMEM;
+
+		for (i = 0; i < map->max_osd; i++)
+			map->osd_primary_affinity[i] =
+			    CEPH_OSD_DEFAULT_PRIMARY_AFFINITY;
+	}
+
+	map->osd_primary_affinity[osd] = aff;
+
+	return 0;
+}
+
+static int decode_primary_affinity(void **p, void *end,
+				   struct ceph_osdmap *map)
+{
+	u32 len, i;
+
+	ceph_decode_32_safe(p, end, len, e_inval);
+	if (len == 0) {
+		kvfree(map->osd_primary_affinity);
+		map->osd_primary_affinity = NULL;
+		return 0;
+	}
+	if (len != map->max_osd)
+		goto e_inval;
+
+	ceph_decode_need(p, end, map->max_osd*sizeof(u32), e_inval);
+
+	for (i = 0; i < map->max_osd; i++) {
+		int ret;
+
+		ret = set_primary_affinity(map, i, ceph_decode_32(p));
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+
+e_inval:
+	return -EINVAL;
+}
+
+static int decode_new_primary_affinity(void **p, void *end,
+				       struct ceph_osdmap *map)
+{
+	u32 n;
+
+	ceph_decode_32_safe(p, end, n, e_inval);
+	while (n--) {
+		u32 osd, aff;
+		int ret;
+
+		ceph_decode_32_safe(p, end, osd, e_inval);
+		ceph_decode_32_safe(p, end, aff, e_inval);
+
+		ret = set_primary_affinity(map, osd, aff);
+		if (ret)
+			return ret;
+
+		osdmap_info(map, "osd%d primary-affinity 0x%x\n", osd, aff);
+	}
+
+	return 0;
+
+e_inval:
+	return -EINVAL;
+}
+
+static struct ceph_pg_mapping *__decode_pg_upmap(void **p, void *end,
+						 bool __unused)
+{
+	return __decode_pg_temp(p, end, false);
+}
+
+static int decode_pg_upmap(void **p, void *end, struct ceph_osdmap *map)
+{
+	return decode_pg_mapping(p, end, &map->pg_upmap, __decode_pg_upmap,
+				 false);
+}
+
+static int decode_new_pg_upmap(void **p, void *end, struct ceph_osdmap *map)
+{
+	return decode_pg_mapping(p, end, &map->pg_upmap, __decode_pg_upmap,
+				 true);
+}
+
+static int decode_old_pg_upmap(void **p, void *end, struct ceph_osdmap *map)
+{
+	return decode_pg_mapping(p, end, &map->pg_upmap, NULL, true);
+}
+
+static struct ceph_pg_mapping *__decode_pg_upmap_items(void **p, void *end,
+						       bool __unused)
+{
+	struct ceph_pg_mapping *pg;
+	u32 len, i;
+
+	ceph_decode_32_safe(p, end, len, e_inval);
+	if (len > (SIZE_MAX - sizeof(*pg)) / (2 * sizeof(u32)))
+		return ERR_PTR(-EINVAL);
+
+	ceph_decode_need(p, end, 2 * len * sizeof(u32), e_inval);
+	pg = alloc_pg_mapping(2 * len * sizeof(u32));
+	if (!pg)
+		return ERR_PTR(-ENOMEM);
+
+	pg->pg_upmap_items.len = len;
+	for (i = 0; i < len; i++) {
+		pg->pg_upmap_items.from_to[i][0] = ceph_decode_32(p);
+		pg->pg_upmap_items.from_to[i][1] = ceph_decode_32(p);
+	}
+
+	return pg;
+
+e_inval:
+	return ERR_PTR(-EINVAL);
+}
+
+static int decode_pg_upmap_items(void **p, void *end, struct ceph_osdmap *map)
+{
+	return decode_pg_mapping(p, end, &map->pg_upmap_items,
+				 __decode_pg_upmap_items, false);
+}
+
+static int decode_new_pg_upmap_items(void **p, void *end,
+				     struct ceph_osdmap *map)
+{
+	return decode_pg_mapping(p, end, &map->pg_upmap_items,
+				 __decode_pg_upmap_items, true);
+}
+
+static int decode_old_pg_upmap_items(void **p, void *end,
+				     struct ceph_osdmap *map)
+{
+	return decode_pg_mapping(p, end, &map->pg_upmap_items, NULL, true);
+}
+
+/*
+ * decode a full map.
+ */
+static int osdmap_decode(void **p, void *end, bool msgr2,
+			 struct ceph_osdmap *map)
+{
+	u8 struct_v;
+	u32 epoch = 0;
+	void *start = *p;
+	u32 max;
+	u32 len, i;
+	int err;
+
+	dout("%s %p to %p len %d\n", __func__, *p, end, (int)(end - *p));
+
+	err = get_osdmap_client_data_v(p, end, "full", &struct_v);
+	if (err)
+		goto bad;
+
+	/* fsid, epoch, created, modified */
+	ceph_decode_need(p, end, sizeof(map->fsid) + sizeof(u32) +
+			 sizeof(map->created) + sizeof(map->modified), e_inval);
+	ceph_decode_copy(p, &map->fsid, sizeof(map->fsid));
+	epoch = map->epoch = ceph_decode_32(p);
+	ceph_decode_copy(p, &map->created, sizeof(map->created));
+	ceph_decode_copy(p, &map->modified, sizeof(map->modified));
+
+	/* pools */
+	err = decode_pools(p, end, map);
+	if (err)
+		goto bad;
+
+	/* pool_name */
+	err = decode_pool_names(p, end, map);
+	if (err)
+		goto bad;
+
+	ceph_decode_32_safe(p, end, map->pool_max, e_inval);
+
+	ceph_decode_32_safe(p, end, map->flags, e_inval);
+
+	/* max_osd */
+	ceph_decode_32_safe(p, end, max, e_inval);
+
+	/* (re)alloc osd arrays */
+	err = osdmap_set_max_osd(map, max);
+	if (err)
+		goto bad;
+
+	/* osd_state, osd_weight, osd_addrs->client_addr */
+	ceph_decode_need(p, end, 3*sizeof(u32) +
+			 map->max_osd*(struct_v >= 5 ? sizeof(u32) :
+						       sizeof(u8)) +
+				       sizeof(*map->osd_weight), e_inval);
+	if (ceph_decode_32(p) != map->max_osd)
+		goto e_inval;
+
+	if (struct_v >= 5) {
+		for (i = 0; i < map->max_osd; i++)
+			map->osd_state[i] = ceph_decode_32(p);
+	} else {
+		for (i = 0; i < map->max_osd; i++)
+			map->osd_state[i] = ceph_decode_8(p);
+	}
+
+	if (ceph_decode_32(p) != map->max_osd)
+		goto e_inval;
+
+	for (i = 0; i < map->max_osd; i++)
+		map->osd_weight[i] = ceph_decode_32(p);
+
+	if (ceph_decode_32(p) != map->max_osd)
+		goto e_inval;
+
+	for (i = 0; i < map->max_osd; i++) {
+		struct ceph_entity_addr *addr = &map->osd_addr[i];
+
+		if (struct_v >= 8)
+			err = ceph_decode_entity_addrvec(p, end, msgr2, addr);
+		else
+			err = ceph_decode_entity_addr(p, end, addr);
+		if (err)
+			goto bad;
+
+		dout("%s osd%d addr %s\n", __func__, i, ceph_pr_addr(addr));
+	}
+
+	/* pg_temp */
+	err = decode_pg_temp(p, end, map);
+	if (err)
+		goto bad;
+
+	/* primary_temp */
+	if (struct_v >= 1) {
+		err = decode_primary_temp(p, end, map);
+		if (err)
+			goto bad;
+	}
+
+	/* primary_affinity */
+	if (struct_v >= 2) {
+		err = decode_primary_affinity(p, end, map);
+		if (err)
+			goto bad;
+	} else {
+		WARN_ON(map->osd_primary_affinity);
+	}
+
+	/* crush */
+	ceph_decode_32_safe(p, end, len, e_inval);
+	err = osdmap_set_crush(map, crush_decode(*p, min(*p + len, end)));
+	if (err)
+		goto bad;
+
+	*p += len;
+	if (struct_v >= 3) {
+		/* erasure_code_profiles */
+		ceph_decode_skip_map_of_map(p, end, string, string, string,
+					    e_inval);
+	}
+
+	if (struct_v >= 4) {
+		err = decode_pg_upmap(p, end, map);
+		if (err)
+			goto bad;
+
+		err = decode_pg_upmap_items(p, end, map);
+		if (err)
+			goto bad;
+	} else {
+		WARN_ON(!RB_EMPTY_ROOT(&map->pg_upmap));
+		WARN_ON(!RB_EMPTY_ROOT(&map->pg_upmap_items));
+	}
+
+	/* ignore the rest */
+	*p = end;
+
+	dout("full osdmap epoch %d max_osd %d\n", map->epoch, map->max_osd);
+	return 0;
+
+e_inval:
+	err = -EINVAL;
+bad:
+	pr_err("corrupt full osdmap (%d) epoch %d off %d (%p of %p-%p)\n",
+	       err, epoch, (int)(*p - start), *p, start, end);
+	print_hex_dump(KERN_DEBUG, "osdmap: ",
+		       DUMP_PREFIX_OFFSET, 16, 1,
+		       start, end - start, true);
+	return err;
+}
+
+/*
+ * Allocate and decode a full map.
+ */
+struct ceph_osdmap *ceph_osdmap_decode(void **p, void *end, bool msgr2)
+{
+	struct ceph_osdmap *map;
+	int ret;
+
+	map = ceph_osdmap_alloc();
+	if (!map)
+		return ERR_PTR(-ENOMEM);
+
+	ret = osdmap_decode(p, end, msgr2, map);
+	if (ret) {
+		ceph_osdmap_destroy(map);
+		return ERR_PTR(ret);
+	}
+
+	return map;
+}
+
+/*
+ * Encoding order is (new_up_client, new_state, new_weight).  Need to
+ * apply in the (new_weight, new_state, new_up_client) order, because
+ * an incremental map may look like e.g.
+ *
+ *     new_up_client: { osd=6, addr=... } # set osd_state and addr
+ *     new_state: { osd=6, xorstate=EXISTS } # clear osd_state
+ */
+static int decode_new_up_state_weight(void **p, void *end, u8 struct_v,
+				      bool msgr2, struct ceph_osdmap *map)
+{
+	void *new_up_client;
+	void *new_state;
+	void *new_weight_end;
+	u32 len;
+	int ret;
+	int i;
+
+	new_up_client = *p;
+	ceph_decode_32_safe(p, end, len, e_inval);
+	for (i = 0; i < len; ++i) {
+		struct ceph_entity_addr addr;
+
+		ceph_decode_skip_32(p, end, e_inval);
+		if (struct_v >= 7)
+			ret = ceph_decode_entity_addrvec(p, end, msgr2, &addr);
+		else
+			ret = ceph_decode_entity_addr(p, end, &addr);
+		if (ret)
+			return ret;
+	}
+
+	new_state = *p;
+	ceph_decode_32_safe(p, end, len, e_inval);
+	len *= sizeof(u32) + (struct_v >= 5 ? sizeof(u32) : sizeof(u8));
+	ceph_decode_need(p, end, len, e_inval);
+	*p += len;
+
+	/* new_weight */
+	ceph_decode_32_safe(p, end, len, e_inval);
+	while (len--) {
+		s32 osd;
+		u32 w;
+
+		ceph_decode_need(p, end, 2*sizeof(u32), e_inval);
+		osd = ceph_decode_32(p);
+		w = ceph_decode_32(p);
+		BUG_ON(osd >= map->max_osd);
+		osdmap_info(map, "osd%d weight 0x%x %s\n", osd, w,
+			    w == CEPH_OSD_IN ? "(in)" :
+			    (w == CEPH_OSD_OUT ? "(out)" : ""));
+		map->osd_weight[osd] = w;
+
+		/*
+		 * If we are marking in, set the EXISTS, and clear the
+		 * AUTOOUT and NEW bits.
+		 */
+		if (w) {
+			map->osd_state[osd] |= CEPH_OSD_EXISTS;
+			map->osd_state[osd] &= ~(CEPH_OSD_AUTOOUT |
+						 CEPH_OSD_NEW);
+		}
+	}
+	new_weight_end = *p;
+
+	/* new_state (up/down) */
+	*p = new_state;
+	len = ceph_decode_32(p);
+	while (len--) {
+		s32 osd;
+		u32 xorstate;
+
+		osd = ceph_decode_32(p);
+		if (struct_v >= 5)
+			xorstate = ceph_decode_32(p);
+		else
+			xorstate = ceph_decode_8(p);
+		if (xorstate == 0)
+			xorstate = CEPH_OSD_UP;
+		BUG_ON(osd >= map->max_osd);
+		if ((map->osd_state[osd] & CEPH_OSD_UP) &&
+		    (xorstate & CEPH_OSD_UP))
+			osdmap_info(map, "osd%d down\n", osd);
+		if ((map->osd_state[osd] & CEPH_OSD_EXISTS) &&
+		    (xorstate & CEPH_OSD_EXISTS)) {
+			osdmap_info(map, "osd%d does not exist\n", osd);
+			ret = set_primary_affinity(map, osd,
+						   CEPH_OSD_DEFAULT_PRIMARY_AFFINITY);
+			if (ret)
+				return ret;
+			memset(map->osd_addr + osd, 0, sizeof(*map->osd_addr));
+			map->osd_state[osd] = 0;
+		} else {
+			map->osd_state[osd] ^= xorstate;
+		}
+	}
+
+	/* new_up_client */
+	*p = new_up_client;
+	len = ceph_decode_32(p);
+	while (len--) {
+		s32 osd;
+		struct ceph_entity_addr addr;
+
+		osd = ceph_decode_32(p);
+		BUG_ON(osd >= map->max_osd);
+		if (struct_v >= 7)
+			ret = ceph_decode_entity_addrvec(p, end, msgr2, &addr);
+		else
+			ret = ceph_decode_entity_addr(p, end, &addr);
+		if (ret)
+			return ret;
+
+		dout("%s osd%d addr %s\n", __func__, osd, ceph_pr_addr(&addr));
+
+		osdmap_info(map, "osd%d up\n", osd);
+		map->osd_state[osd] |= CEPH_OSD_EXISTS | CEPH_OSD_UP;
+		map->osd_addr[osd] = addr;
+	}
+
+	*p = new_weight_end;
+	return 0;
+
+e_inval:
+	return -EINVAL;
+}
+
+/*
+ * decode and apply an incremental map update.
+ */
+struct ceph_osdmap *osdmap_apply_incremental(void **p, void *end, bool msgr2,
+					     struct ceph_osdmap *map)
+{
+	struct ceph_fsid fsid;
+	u32 epoch = 0;
+	struct ceph_timespec modified;
+	s32 len;
+	u64 pool;
+	__s64 new_pool_max;
+	__s32 new_flags, max;
+	void *start = *p;
+	int err;
+	u8 struct_v;
+
+	dout("%s %p to %p len %d\n", __func__, *p, end, (int)(end - *p));
+
+	err = get_osdmap_client_data_v(p, end, "inc", &struct_v);
+	if (err)
+		goto bad;
+
+	/* fsid, epoch, modified, new_pool_max, new_flags */
+	ceph_decode_need(p, end, sizeof(fsid) + sizeof(u32) + sizeof(modified) +
+			 sizeof(u64) + sizeof(u32), e_inval);
+	ceph_decode_copy(p, &fsid, sizeof(fsid));
+	epoch = ceph_decode_32(p);
+	BUG_ON(epoch != map->epoch+1);
+	ceph_decode_copy(p, &modified, sizeof(modified));
+	new_pool_max = ceph_decode_64(p);
+	new_flags = ceph_decode_32(p);
+
+	/* full map? */
+	ceph_decode_32_safe(p, end, len, e_inval);
+	if (len > 0) {
+		dout("apply_incremental full map len %d, %p to %p\n",
+		     len, *p, end);
+		return ceph_osdmap_decode(p, min(*p+len, end), msgr2);
+	}
+
+	/* new crush? */
+	ceph_decode_32_safe(p, end, len, e_inval);
+	if (len > 0) {
+		err = osdmap_set_crush(map,
+				       crush_decode(*p, min(*p + len, end)));
+		if (err)
+			goto bad;
+		*p += len;
+	}
+
+	/* new flags? */
+	if (new_flags >= 0)
+		map->flags = new_flags;
+	if (new_pool_max >= 0)
+		map->pool_max = new_pool_max;
+
+	/* new max? */
+	ceph_decode_32_safe(p, end, max, e_inval);
+	if (max >= 0) {
+		err = osdmap_set_max_osd(map, max);
+		if (err)
+			goto bad;
+	}
+
+	map->epoch++;
+	map->modified = modified;
+
+	/* new_pools */
+	err = decode_new_pools(p, end, map);
+	if (err)
+		goto bad;
+
+	/* new_pool_names */
+	err = decode_pool_names(p, end, map);
+	if (err)
+		goto bad;
+
+	/* old_pool */
+	ceph_decode_32_safe(p, end, len, e_inval);
+	while (len--) {
+		struct ceph_pg_pool_info *pi;
+
+		ceph_decode_64_safe(p, end, pool, e_inval);
+		pi = lookup_pg_pool(&map->pg_pools, pool);
+		if (pi)
+			__remove_pg_pool(&map->pg_pools, pi);
+	}
+
+	/* new_up_client, new_state, new_weight */
+	err = decode_new_up_state_weight(p, end, struct_v, msgr2, map);
+	if (err)
+		goto bad;
+
+	/* new_pg_temp */
+	err = decode_new_pg_temp(p, end, map);
+	if (err)
+		goto bad;
+
+	/* new_primary_temp */
+	if (struct_v >= 1) {
+		err = decode_new_primary_temp(p, end, map);
+		if (err)
+			goto bad;
+	}
+
+	/* new_primary_affinity */
+	if (struct_v >= 2) {
+		err = decode_new_primary_affinity(p, end, map);
+		if (err)
+			goto bad;
+	}
+
+	if (struct_v >= 3) {
+		/* new_erasure_code_profiles */
+		ceph_decode_skip_map_of_map(p, end, string, string, string,
+					    e_inval);
+		/* old_erasure_code_profiles */
+		ceph_decode_skip_set(p, end, string, e_inval);
+	}
+
+	if (struct_v >= 4) {
+		err = decode_new_pg_upmap(p, end, map);
+		if (err)
+			goto bad;
+
+		err = decode_old_pg_upmap(p, end, map);
+		if (err)
+			goto bad;
+
+		err = decode_new_pg_upmap_items(p, end, map);
+		if (err)
+			goto bad;
+
+		err = decode_old_pg_upmap_items(p, end, map);
+		if (err)
+			goto bad;
+	}
+
+	/* ignore the rest */
+	*p = end;
+
+	dout("inc osdmap epoch %d max_osd %d\n", map->epoch, map->max_osd);
+	return map;
+
+e_inval:
+	err = -EINVAL;
+bad:
+	pr_err("corrupt inc osdmap (%d) epoch %d off %d (%p of %p-%p)\n",
+	       err, epoch, (int)(*p - start), *p, start, end);
+	print_hex_dump(KERN_DEBUG, "osdmap: ",
+		       DUMP_PREFIX_OFFSET, 16, 1,
+		       start, end - start, true);
+	return ERR_PTR(err);
+}
+
+void ceph_oloc_copy(struct ceph_object_locator *dest,
+		    const struct ceph_object_locator *src)
+{
+	ceph_oloc_destroy(dest);
+
+	dest->pool = src->pool;
+	if (src->pool_ns)
+		dest->pool_ns = ceph_get_string(src->pool_ns);
+	else
+		dest->pool_ns = NULL;
+}
+EXPORT_SYMBOL(ceph_oloc_copy);
+
+void ceph_oloc_destroy(struct ceph_object_locator *oloc)
+{
+	ceph_put_string(oloc->pool_ns);
+}
+EXPORT_SYMBOL(ceph_oloc_destroy);
+
+void ceph_oid_copy(struct ceph_object_id *dest,
+		   const struct ceph_object_id *src)
+{
+	ceph_oid_destroy(dest);
+
+	if (src->name != src->inline_name) {
+		/* very rare, see ceph_object_id definition */
+		dest->name = kmalloc(src->name_len + 1,
+				     GFP_NOIO | __GFP_NOFAIL);
+	} else {
+		dest->name = dest->inline_name;
+	}
+	memcpy(dest->name, src->name, src->name_len + 1);
+	dest->name_len = src->name_len;
+}
+EXPORT_SYMBOL(ceph_oid_copy);
+
+static __printf(2, 0)
+int oid_printf_vargs(struct ceph_object_id *oid, const char *fmt, va_list ap)
+{
+	int len;
+
+	WARN_ON(!ceph_oid_empty(oid));
+
+	len = vsnprintf(oid->inline_name, sizeof(oid->inline_name), fmt, ap);
+	if (len >= sizeof(oid->inline_name))
+		return len;
+
+	oid->name_len = len;
+	return 0;
+}
+
+/*
+ * If oid doesn't fit into inline buffer, BUG.
+ */
+void ceph_oid_printf(struct ceph_object_id *oid, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	BUG_ON(oid_printf_vargs(oid, fmt, ap));
+	va_end(ap);
+}
+EXPORT_SYMBOL(ceph_oid_printf);
+
+static __printf(3, 0)
+int oid_aprintf_vargs(struct ceph_object_id *oid, gfp_t gfp,
+		      const char *fmt, va_list ap)
+{
+	va_list aq;
+	int len;
+
+	va_copy(aq, ap);
+	len = oid_printf_vargs(oid, fmt, aq);
+	va_end(aq);
+
+	if (len) {
+		char *external_name;
+
+		external_name = kmalloc(len + 1, gfp);
+		if (!external_name)
+			return -ENOMEM;
+
+		oid->name = external_name;
+		WARN_ON(vsnprintf(oid->name, len + 1, fmt, ap) != len);
+		oid->name_len = len;
+	}
+
+	return 0;
+}
+
+/*
+ * If oid doesn't fit into inline buffer, allocate.
+ */
+int ceph_oid_aprintf(struct ceph_object_id *oid, gfp_t gfp,
+		     const char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, fmt);
+	ret = oid_aprintf_vargs(oid, gfp, fmt, ap);
+	va_end(ap);
+
+	return ret;
+}
+EXPORT_SYMBOL(ceph_oid_aprintf);
+
+void ceph_oid_destroy(struct ceph_object_id *oid)
+{
+	if (oid->name != oid->inline_name)
+		kfree(oid->name);
+}
+EXPORT_SYMBOL(ceph_oid_destroy);
+
+/*
+ * osds only
+ */
+static bool __osds_equal(const struct ceph_osds *lhs,
+			 const struct ceph_osds *rhs)
+{
+	if (lhs->size == rhs->size &&
+	    !memcmp(lhs->osds, rhs->osds, rhs->size * sizeof(rhs->osds[0])))
+		return true;
+
+	return false;
+}
+
+/*
+ * osds + primary
+ */
+static bool osds_equal(const struct ceph_osds *lhs,
+		       const struct ceph_osds *rhs)
+{
+	if (__osds_equal(lhs, rhs) &&
+	    lhs->primary == rhs->primary)
+		return true;
+
+	return false;
+}
+
+static bool osds_valid(const struct ceph_osds *set)
+{
+	/* non-empty set */
+	if (set->size > 0 && set->primary >= 0)
+		return true;
+
+	/* empty can_shift_osds set */
+	if (!set->size && set->primary == -1)
+		return true;
+
+	/* empty !can_shift_osds set - all NONE */
+	if (set->size > 0 && set->primary == -1) {
+		int i;
+
+		for (i = 0; i < set->size; i++) {
+			if (set->osds[i] != CRUSH_ITEM_NONE)
+				break;
+		}
+		if (i == set->size)
+			return true;
+	}
+
+	return false;
+}
+
+void ceph_osds_copy(struct ceph_osds *dest, const struct ceph_osds *src)
+{
+	memcpy(dest->osds, src->osds, src->size * sizeof(src->osds[0]));
+	dest->size = src->size;
+	dest->primary = src->primary;
+}
+
+bool ceph_pg_is_split(const struct ceph_pg *pgid, u32 old_pg_num,
+		      u32 new_pg_num)
+{
+	int old_bits = calc_bits_of(old_pg_num);
+	int old_mask = (1 << old_bits) - 1;
+	int n;
+
+	WARN_ON(pgid->seed >= old_pg_num);
+	if (new_pg_num <= old_pg_num)
+		return false;
+
+	for (n = 1; ; n++) {
+		int next_bit = n << (old_bits - 1);
+		u32 s = next_bit | pgid->seed;
+
+		if (s < old_pg_num || s == pgid->seed)
+			continue;
+		if (s >= new_pg_num)
+			break;
+
+		s = ceph_stable_mod(s, old_pg_num, old_mask);
+		if (s == pgid->seed)
+			return true;
+	}
+
+	return false;
+}
+
+bool ceph_is_new_interval(const struct ceph_osds *old_acting,
+			  const struct ceph_osds *new_acting,
+			  const struct ceph_osds *old_up,
+			  const struct ceph_osds *new_up,
+			  int old_size,
+			  int new_size,
+			  int old_min_size,
+			  int new_min_size,
+			  u32 old_pg_num,
+			  u32 new_pg_num,
+			  bool old_sort_bitwise,
+			  bool new_sort_bitwise,
+			  bool old_recovery_deletes,
+			  bool new_recovery_deletes,
+			  const struct ceph_pg *pgid)
+{
+	return !osds_equal(old_acting, new_acting) ||
+	       !osds_equal(old_up, new_up) ||
+	       old_size != new_size ||
+	       old_min_size != new_min_size ||
+	       ceph_pg_is_split(pgid, old_pg_num, new_pg_num) ||
+	       old_sort_bitwise != new_sort_bitwise ||
+	       old_recovery_deletes != new_recovery_deletes;
+}
+
+static int calc_pg_rank(int osd, const struct ceph_osds *acting)
+{
+	int i;
+
+	for (i = 0; i < acting->size; i++) {
+		if (acting->osds[i] == osd)
+			return i;
+	}
+
+	return -1;
+}
+
+static bool primary_changed(const struct ceph_osds *old_acting,
+			    const struct ceph_osds *new_acting)
+{
+	if (!old_acting->size && !new_acting->size)
+		return false; /* both still empty */
+
+	if (!old_acting->size ^ !new_acting->size)
+		return true; /* was empty, now not, or vice versa */
+
+	if (old_acting->primary != new_acting->primary)
+		return true; /* primary changed */
+
+	if (calc_pg_rank(old_acting->primary, old_acting) !=
+	    calc_pg_rank(new_acting->primary, new_acting))
+		return true;
+
+	return false; /* same primary (tho replicas may have changed) */
+}
+
+bool ceph_osds_changed(const struct ceph_osds *old_acting,
+		       const struct ceph_osds *new_acting,
+		       bool any_change)
+{
+	if (primary_changed(old_acting, new_acting))
+		return true;
+
+	if (any_change && !__osds_equal(old_acting, new_acting))
+		return true;
+
+	return false;
+}
+
+/*
+ * Map an object into a PG.
+ *
+ * Should only be called with target_oid and target_oloc (as opposed to
+ * base_oid and base_oloc), since tiering isn't taken into account.
+ */
+void __ceph_object_locator_to_pg(struct ceph_pg_pool_info *pi,
+				 const struct ceph_object_id *oid,
+				 const struct ceph_object_locator *oloc,
+				 struct ceph_pg *raw_pgid)
+{
+	WARN_ON(pi->id != oloc->pool);
+
+	if (!oloc->pool_ns) {
+		raw_pgid->pool = oloc->pool;
+		raw_pgid->seed = ceph_str_hash(pi->object_hash, oid->name,
+					     oid->name_len);
+		dout("%s %s -> raw_pgid %llu.%x\n", __func__, oid->name,
+		     raw_pgid->pool, raw_pgid->seed);
+	} else {
+		char stack_buf[256];
+		char *buf = stack_buf;
+		int nsl = oloc->pool_ns->len;
+		size_t total = nsl + 1 + oid->name_len;
+
+		if (total > sizeof(stack_buf))
+			buf = kmalloc(total, GFP_NOIO | __GFP_NOFAIL);
+		memcpy(buf, oloc->pool_ns->str, nsl);
+		buf[nsl] = '\037';
+		memcpy(buf + nsl + 1, oid->name, oid->name_len);
+		raw_pgid->pool = oloc->pool;
+		raw_pgid->seed = ceph_str_hash(pi->object_hash, buf, total);
+		if (buf != stack_buf)
+			kfree(buf);
+		dout("%s %s ns %.*s -> raw_pgid %llu.%x\n", __func__,
+		     oid->name, nsl, oloc->pool_ns->str,
+		     raw_pgid->pool, raw_pgid->seed);
+	}
+}
+
+int ceph_object_locator_to_pg(struct ceph_osdmap *osdmap,
+			      const struct ceph_object_id *oid,
+			      const struct ceph_object_locator *oloc,
+			      struct ceph_pg *raw_pgid)
+{
+	struct ceph_pg_pool_info *pi;
+
+	pi = ceph_pg_pool_by_id(osdmap, oloc->pool);
+	if (!pi)
+		return -ENOENT;
+
+	__ceph_object_locator_to_pg(pi, oid, oloc, raw_pgid);
+	return 0;
+}
+EXPORT_SYMBOL(ceph_object_locator_to_pg);
+
+/*
+ * Map a raw PG (full precision ps) into an actual PG.
+ */
+static void raw_pg_to_pg(struct ceph_pg_pool_info *pi,
+			 const struct ceph_pg *raw_pgid,
+			 struct ceph_pg *pgid)
+{
+	pgid->pool = raw_pgid->pool;
+	pgid->seed = ceph_stable_mod(raw_pgid->seed, pi->pg_num,
+				     pi->pg_num_mask);
+}
+
+/*
+ * Map a raw PG (full precision ps) into a placement ps (placement
+ * seed).  Include pool id in that value so that different pools don't
+ * use the same seeds.
+ */
+static u32 raw_pg_to_pps(struct ceph_pg_pool_info *pi,
+			 const struct ceph_pg *raw_pgid)
+{
+	if (pi->flags & CEPH_POOL_FLAG_HASHPSPOOL) {
+		/* hash pool id and seed so that pool PGs do not overlap */
+		return crush_hash32_2(CRUSH_HASH_RJENKINS1,
+				      ceph_stable_mod(raw_pgid->seed,
+						      pi->pgp_num,
+						      pi->pgp_num_mask),
+				      raw_pgid->pool);
+	} else {
+		/*
+		 * legacy behavior: add ps and pool together.  this is
+		 * not a great approach because the PGs from each pool
+		 * will overlap on top of each other: 0.5 == 1.4 ==
+		 * 2.3 == ...
+		 */
+		return ceph_stable_mod(raw_pgid->seed, pi->pgp_num,
+				       pi->pgp_num_mask) +
+		       (unsigned)raw_pgid->pool;
+	}
+}
+
+/*
+ * Magic value used for a "default" fallback choose_args, used if the
+ * crush_choose_arg_map passed to do_crush() does not exist.  If this
+ * also doesn't exist, fall back to canonical weights.
+ */
+#define CEPH_DEFAULT_CHOOSE_ARGS	-1
+
+static int do_crush(struct ceph_osdmap *map, int ruleno, int x,
+		    int *result, int result_max,
+		    const __u32 *weight, int weight_max,
+		    s64 choose_args_index)
+{
+	struct crush_choose_arg_map *arg_map;
+	struct crush_work *work;
+	int r;
+
+	BUG_ON(result_max > CEPH_PG_MAX_SIZE);
+
+	arg_map = lookup_choose_arg_map(&map->crush->choose_args,
+					choose_args_index);
+	if (!arg_map)
+		arg_map = lookup_choose_arg_map(&map->crush->choose_args,
+						CEPH_DEFAULT_CHOOSE_ARGS);
+
+	work = get_workspace(&map->crush_wsm, map->crush);
+	r = crush_do_rule(map->crush, ruleno, x, result, result_max,
+			  weight, weight_max, work,
+			  arg_map ? arg_map->args : NULL);
+	put_workspace(&map->crush_wsm, work);
+	return r;
+}
+
+static void remove_nonexistent_osds(struct ceph_osdmap *osdmap,
+				    struct ceph_pg_pool_info *pi,
+				    struct ceph_osds *set)
+{
+	int i;
+
+	if (ceph_can_shift_osds(pi)) {
+		int removed = 0;
+
+		/* shift left */
+		for (i = 0; i < set->size; i++) {
+			if (!ceph_osd_exists(osdmap, set->osds[i])) {
+				removed++;
+				continue;
+			}
+			if (removed)
+				set->osds[i - removed] = set->osds[i];
+		}
+		set->size -= removed;
+	} else {
+		/* set dne devices to NONE */
+		for (i = 0; i < set->size; i++) {
+			if (!ceph_osd_exists(osdmap, set->osds[i]))
+				set->osds[i] = CRUSH_ITEM_NONE;
+		}
+	}
+}
+
+/*
+ * Calculate raw set (CRUSH output) for given PG and filter out
+ * nonexistent OSDs.  ->primary is undefined for a raw set.
+ *
+ * Placement seed (CRUSH input) is returned through @ppps.
+ */
+static void pg_to_raw_osds(struct ceph_osdmap *osdmap,
+			   struct ceph_pg_pool_info *pi,
+			   const struct ceph_pg *raw_pgid,
+			   struct ceph_osds *raw,
+			   u32 *ppps)
+{
+	u32 pps = raw_pg_to_pps(pi, raw_pgid);
+	int ruleno;
+	int len;
+
+	ceph_osds_init(raw);
+	if (ppps)
+		*ppps = pps;
+
+	ruleno = crush_find_rule(osdmap->crush, pi->crush_ruleset, pi->type,
+				 pi->size);
+	if (ruleno < 0) {
+		pr_err("no crush rule: pool %lld ruleset %d type %d size %d\n",
+		       pi->id, pi->crush_ruleset, pi->type, pi->size);
+		return;
+	}
+
+	if (pi->size > ARRAY_SIZE(raw->osds)) {
+		pr_err_ratelimited("pool %lld ruleset %d type %d too wide: size %d > %zu\n",
+		       pi->id, pi->crush_ruleset, pi->type, pi->size,
+		       ARRAY_SIZE(raw->osds));
+		return;
+	}
+
+	len = do_crush(osdmap, ruleno, pps, raw->osds, pi->size,
+		       osdmap->osd_weight, osdmap->max_osd, pi->id);
+	if (len < 0) {
+		pr_err("error %d from crush rule %d: pool %lld ruleset %d type %d size %d\n",
+		       len, ruleno, pi->id, pi->crush_ruleset, pi->type,
+		       pi->size);
+		return;
+	}
+
+	raw->size = len;
+	remove_nonexistent_osds(osdmap, pi, raw);
+}
+
+/* apply pg_upmap[_items] mappings */
+static void apply_upmap(struct ceph_osdmap *osdmap,
+			const struct ceph_pg *pgid,
+			struct ceph_osds *raw)
+{
+	struct ceph_pg_mapping *pg;
+	int i, j;
+
+	pg = lookup_pg_mapping(&osdmap->pg_upmap, pgid);
+	if (pg) {
+		/* make sure targets aren't marked out */
+		for (i = 0; i < pg->pg_upmap.len; i++) {
+			int osd = pg->pg_upmap.osds[i];
+
+			if (osd != CRUSH_ITEM_NONE &&
+			    osd < osdmap->max_osd &&
+			    osdmap->osd_weight[osd] == 0) {
+				/* reject/ignore explicit mapping */
+				return;
+			}
+		}
+		for (i = 0; i < pg->pg_upmap.len; i++)
+			raw->osds[i] = pg->pg_upmap.osds[i];
+		raw->size = pg->pg_upmap.len;
+		/* check and apply pg_upmap_items, if any */
+	}
+
+	pg = lookup_pg_mapping(&osdmap->pg_upmap_items, pgid);
+	if (pg) {
+		/*
+		 * Note: this approach does not allow a bidirectional swap,
+		 * e.g., [[1,2],[2,1]] applied to [0,1,2] -> [0,2,1].
+		 */
+		for (i = 0; i < pg->pg_upmap_items.len; i++) {
+			int from = pg->pg_upmap_items.from_to[i][0];
+			int to = pg->pg_upmap_items.from_to[i][1];
+			int pos = -1;
+			bool exists = false;
+
+			/* make sure replacement doesn't already appear */
+			for (j = 0; j < raw->size; j++) {
+				int osd = raw->osds[j];
+
+				if (osd == to) {
+					exists = true;
+					break;
+				}
+				/* ignore mapping if target is marked out */
+				if (osd == from && pos < 0 &&
+				    !(to != CRUSH_ITEM_NONE &&
+				      to < osdmap->max_osd &&
+				      osdmap->osd_weight[to] == 0)) {
+					pos = j;
+				}
+			}
+			if (!exists && pos >= 0)
+				raw->osds[pos] = to;
+		}
+	}
+}
+
+/*
+ * Given raw set, calculate up set and up primary.  By definition of an
+ * up set, the result won't contain nonexistent or down OSDs.
+ *
+ * This is done in-place - on return @set is the up set.  If it's
+ * empty, ->primary will remain undefined.
+ */
+static void raw_to_up_osds(struct ceph_osdmap *osdmap,
+			   struct ceph_pg_pool_info *pi,
+			   struct ceph_osds *set)
+{
+	int i;
+
+	/* ->primary is undefined for a raw set */
+	BUG_ON(set->primary != -1);
+
+	if (ceph_can_shift_osds(pi)) {
+		int removed = 0;
+
+		/* shift left */
+		for (i = 0; i < set->size; i++) {
+			if (ceph_osd_is_down(osdmap, set->osds[i])) {
+				removed++;
+				continue;
+			}
+			if (removed)
+				set->osds[i - removed] = set->osds[i];
+		}
+		set->size -= removed;
+		if (set->size > 0)
+			set->primary = set->osds[0];
+	} else {
+		/* set down/dne devices to NONE */
+		for (i = set->size - 1; i >= 0; i--) {
+			if (ceph_osd_is_down(osdmap, set->osds[i]))
+				set->osds[i] = CRUSH_ITEM_NONE;
+			else
+				set->primary = set->osds[i];
+		}
+	}
+}
+
+static void apply_primary_affinity(struct ceph_osdmap *osdmap,
+				   struct ceph_pg_pool_info *pi,
+				   u32 pps,
+				   struct ceph_osds *up)
+{
+	int i;
+	int pos = -1;
+
+	/*
+	 * Do we have any non-default primary_affinity values for these
+	 * osds?
+	 */
+	if (!osdmap->osd_primary_affinity)
+		return;
+
+	for (i = 0; i < up->size; i++) {
+		int osd = up->osds[i];
+
+		if (osd != CRUSH_ITEM_NONE &&
+		    osdmap->osd_primary_affinity[osd] !=
+					CEPH_OSD_DEFAULT_PRIMARY_AFFINITY) {
+			break;
+		}
+	}
+	if (i == up->size)
+		return;
+
+	/*
+	 * Pick the primary.  Feed both the seed (for the pg) and the
+	 * osd into the hash/rng so that a proportional fraction of an
+	 * osd's pgs get rejected as primary.
+	 */
+	for (i = 0; i < up->size; i++) {
+		int osd = up->osds[i];
+		u32 aff;
+
+		if (osd == CRUSH_ITEM_NONE)
+			continue;
+
+		aff = osdmap->osd_primary_affinity[osd];
+		if (aff < CEPH_OSD_MAX_PRIMARY_AFFINITY &&
+		    (crush_hash32_2(CRUSH_HASH_RJENKINS1,
+				    pps, osd) >> 16) >= aff) {
+			/*
+			 * We chose not to use this primary.  Note it
+			 * anyway as a fallback in case we don't pick
+			 * anyone else, but keep looking.
+			 */
+			if (pos < 0)
+				pos = i;
+		} else {
+			pos = i;
+			break;
+		}
+	}
+	if (pos < 0)
+		return;
+
+	up->primary = up->osds[pos];
+
+	if (ceph_can_shift_osds(pi) && pos > 0) {
+		/* move the new primary to the front */
+		for (i = pos; i > 0; i--)
+			up->osds[i] = up->osds[i - 1];
+		up->osds[0] = up->primary;
+	}
+}
+
+/*
+ * Get pg_temp and primary_temp mappings for given PG.
+ *
+ * Note that a PG may have none, only pg_temp, only primary_temp or
+ * both pg_temp and primary_temp mappings.  This means @temp isn't
+ * always a valid OSD set on return: in the "only primary_temp" case,
+ * @temp will have its ->primary >= 0 but ->size == 0.
+ */
+static void get_temp_osds(struct ceph_osdmap *osdmap,
+			  struct ceph_pg_pool_info *pi,
+			  const struct ceph_pg *pgid,
+			  struct ceph_osds *temp)
+{
+	struct ceph_pg_mapping *pg;
+	int i;
+
+	ceph_osds_init(temp);
+
+	/* pg_temp? */
+	pg = lookup_pg_mapping(&osdmap->pg_temp, pgid);
+	if (pg) {
+		for (i = 0; i < pg->pg_temp.len; i++) {
+			if (ceph_osd_is_down(osdmap, pg->pg_temp.osds[i])) {
+				if (ceph_can_shift_osds(pi))
+					continue;
+
+				temp->osds[temp->size++] = CRUSH_ITEM_NONE;
+			} else {
+				temp->osds[temp->size++] = pg->pg_temp.osds[i];
+			}
+		}
+
+		/* apply pg_temp's primary */
+		for (i = 0; i < temp->size; i++) {
+			if (temp->osds[i] != CRUSH_ITEM_NONE) {
+				temp->primary = temp->osds[i];
+				break;
+			}
+		}
+	}
+
+	/* primary_temp? */
+	pg = lookup_pg_mapping(&osdmap->primary_temp, pgid);
+	if (pg)
+		temp->primary = pg->primary_temp.osd;
+}
+
+/*
+ * Map a PG to its acting set as well as its up set.
+ *
+ * Acting set is used for data mapping purposes, while up set can be
+ * recorded for detecting interval changes and deciding whether to
+ * resend a request.
+ */
+void ceph_pg_to_up_acting_osds(struct ceph_osdmap *osdmap,
+			       struct ceph_pg_pool_info *pi,
+			       const struct ceph_pg *raw_pgid,
+			       struct ceph_osds *up,
+			       struct ceph_osds *acting)
+{
+	struct ceph_pg pgid;
+	u32 pps;
+
+	WARN_ON(pi->id != raw_pgid->pool);
+	raw_pg_to_pg(pi, raw_pgid, &pgid);
+
+	pg_to_raw_osds(osdmap, pi, raw_pgid, up, &pps);
+	apply_upmap(osdmap, &pgid, up);
+	raw_to_up_osds(osdmap, pi, up);
+	apply_primary_affinity(osdmap, pi, pps, up);
+	get_temp_osds(osdmap, pi, &pgid, acting);
+	if (!acting->size) {
+		memcpy(acting->osds, up->osds, up->size * sizeof(up->osds[0]));
+		acting->size = up->size;
+		if (acting->primary == -1)
+			acting->primary = up->primary;
+	}
+	WARN_ON(!osds_valid(up) || !osds_valid(acting));
+}
+
+bool ceph_pg_to_primary_shard(struct ceph_osdmap *osdmap,
+			      struct ceph_pg_pool_info *pi,
+			      const struct ceph_pg *raw_pgid,
+			      struct ceph_spg *spgid)
+{
+	struct ceph_pg pgid;
+	struct ceph_osds up, acting;
+	int i;
+
+	WARN_ON(pi->id != raw_pgid->pool);
+	raw_pg_to_pg(pi, raw_pgid, &pgid);
+
+	if (ceph_can_shift_osds(pi)) {
+		spgid->pgid = pgid; /* struct */
+		spgid->shard = CEPH_SPG_NOSHARD;
+		return true;
+	}
+
+	ceph_pg_to_up_acting_osds(osdmap, pi, &pgid, &up, &acting);
+	for (i = 0; i < acting.size; i++) {
+		if (acting.osds[i] == acting.primary) {
+			spgid->pgid = pgid; /* struct */
+			spgid->shard = i;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+/*
+ * Return acting primary for given PG, or -1 if none.
+ */
+int ceph_pg_to_acting_primary(struct ceph_osdmap *osdmap,
+			      const struct ceph_pg *raw_pgid)
+{
+	struct ceph_pg_pool_info *pi;
+	struct ceph_osds up, acting;
+
+	pi = ceph_pg_pool_by_id(osdmap, raw_pgid->pool);
+	if (!pi)
+		return -1;
+
+	ceph_pg_to_up_acting_osds(osdmap, pi, raw_pgid, &up, &acting);
+	return acting.primary;
+}
+EXPORT_SYMBOL(ceph_pg_to_acting_primary);
+
+static struct crush_loc_node *alloc_crush_loc(size_t type_name_len,
+					      size_t name_len)
+{
+	struct crush_loc_node *loc;
+
+	loc = kmalloc(sizeof(*loc) + type_name_len + name_len + 2, GFP_NOIO);
+	if (!loc)
+		return NULL;
+
+	RB_CLEAR_NODE(&loc->cl_node);
+	return loc;
+}
+
+static void free_crush_loc(struct crush_loc_node *loc)
+{
+	WARN_ON(!RB_EMPTY_NODE(&loc->cl_node));
+
+	kfree(loc);
+}
+
+static int crush_loc_compare(const struct crush_loc *loc1,
+			     const struct crush_loc *loc2)
+{
+	return strcmp(loc1->cl_type_name, loc2->cl_type_name) ?:
+	       strcmp(loc1->cl_name, loc2->cl_name);
+}
+
+DEFINE_RB_FUNCS2(crush_loc, struct crush_loc_node, cl_loc, crush_loc_compare,
+		 RB_BYPTR, const struct crush_loc *, cl_node)
+
+/*
+ * Parses a set of <bucket type name>':'<bucket name> pairs separated
+ * by '|', e.g. "rack:foo1|rack:foo2|datacenter:bar".
+ *
+ * Note that @crush_location is modified by strsep().
+ */
+int ceph_parse_crush_location(char *crush_location, struct rb_root *locs)
+{
+	struct crush_loc_node *loc;
+	const char *type_name, *name, *colon;
+	size_t type_name_len, name_len;
+
+	dout("%s '%s'\n", __func__, crush_location);
+	while ((type_name = strsep(&crush_location, "|"))) {
+		colon = strchr(type_name, ':');
+		if (!colon)
+			return -EINVAL;
+
+		type_name_len = colon - type_name;
+		if (type_name_len == 0)
+			return -EINVAL;
+
+		name = colon + 1;
+		name_len = strlen(name);
+		if (name_len == 0)
+			return -EINVAL;
+
+		loc = alloc_crush_loc(type_name_len, name_len);
+		if (!loc)
+			return -ENOMEM;
+
+		loc->cl_loc.cl_type_name = loc->cl_data;
+		memcpy(loc->cl_loc.cl_type_name, type_name, type_name_len);
+		loc->cl_loc.cl_type_name[type_name_len] = '\0';
+
+		loc->cl_loc.cl_name = loc->cl_data + type_name_len + 1;
+		memcpy(loc->cl_loc.cl_name, name, name_len);
+		loc->cl_loc.cl_name[name_len] = '\0';
+
+		if (!__insert_crush_loc(locs, loc)) {
+			free_crush_loc(loc);
+			return -EEXIST;
+		}
+
+		dout("%s type_name '%s' name '%s'\n", __func__,
+		     loc->cl_loc.cl_type_name, loc->cl_loc.cl_name);
+	}
+
+	return 0;
+}
+
+int ceph_compare_crush_locs(struct rb_root *locs1, struct rb_root *locs2)
+{
+	struct rb_node *n1 = rb_first(locs1);
+	struct rb_node *n2 = rb_first(locs2);
+	int ret;
+
+	for ( ; n1 && n2; n1 = rb_next(n1), n2 = rb_next(n2)) {
+		struct crush_loc_node *loc1 =
+		    rb_entry(n1, struct crush_loc_node, cl_node);
+		struct crush_loc_node *loc2 =
+		    rb_entry(n2, struct crush_loc_node, cl_node);
+
+		ret = crush_loc_compare(&loc1->cl_loc, &loc2->cl_loc);
+		if (ret)
+			return ret;
+	}
+
+	if (!n1 && n2)
+		return -1;
+	if (n1 && !n2)
+		return 1;
+	return 0;
+}
+
+void ceph_clear_crush_locs(struct rb_root *locs)
+{
+	while (!RB_EMPTY_ROOT(locs)) {
+		struct crush_loc_node *loc =
+		    rb_entry(rb_first(locs), struct crush_loc_node, cl_node);
+
+		erase_crush_loc(locs, loc);
+		free_crush_loc(loc);
+	}
+}
+
+/*
+ * [a-zA-Z0-9-_.]+
+ */
+static bool is_valid_crush_name(const char *name)
+{
+	do {
+		if (!('a' <= *name && *name <= 'z') &&
+		    !('A' <= *name && *name <= 'Z') &&
+		    !('0' <= *name && *name <= '9') &&
+		    *name != '-' && *name != '_' && *name != '.')
+			return false;
+	} while (*++name != '\0');
+
+	return true;
+}
+
+/*
+ * Gets the parent of an item.  Returns its id (<0 because the
+ * parent is always a bucket), type id (>0 for the same reason,
+ * via @parent_type_id) and location (via @parent_loc).  If no
+ * parent, returns 0.
+ *
+ * Does a linear search, as there are no parent pointers of any
+ * kind.  Note that the result is ambiguous for items that occur
+ * multiple times in the map.
+ */
+static int get_immediate_parent(struct crush_map *c, int id,
+				u16 *parent_type_id,
+				struct crush_loc *parent_loc)
+{
+	struct crush_bucket *b;
+	struct crush_name_node *type_cn, *cn;
+	int i, j;
+
+	for (i = 0; i < c->max_buckets; i++) {
+		b = c->buckets[i];
+		if (!b)
+			continue;
+
+		/* ignore per-class shadow hierarchy */
+		cn = lookup_crush_name(&c->names, b->id);
+		if (!cn || !is_valid_crush_name(cn->cn_name))
+			continue;
+
+		for (j = 0; j < b->size; j++) {
+			if (b->items[j] != id)
+				continue;
+
+			*parent_type_id = b->type;
+			type_cn = lookup_crush_name(&c->type_names, b->type);
+			parent_loc->cl_type_name = type_cn->cn_name;
+			parent_loc->cl_name = cn->cn_name;
+			return b->id;
+		}
+	}
+
+	return 0;  /* no parent */
+}
+
+/*
+ * Calculates the locality/distance from an item to a client
+ * location expressed in terms of CRUSH hierarchy as a set of
+ * (bucket type name, bucket name) pairs.  Specifically, looks
+ * for the lowest-valued bucket type for which the location of
+ * @id matches one of the locations in @locs, so for standard
+ * bucket types (host = 1, rack = 3, datacenter = 8, zone = 9)
+ * a matching host is closer than a matching rack and a matching
+ * data center is closer than a matching zone.
+ *
+ * Specifying multiple locations (a "multipath" location) such
+ * as "rack=foo1 rack=foo2 datacenter=bar" is allowed -- @locs
+ * is a multimap.  The locality will be:
+ *
+ * - 3 for OSDs in racks foo1 and foo2
+ * - 8 for OSDs in data center bar
+ * - -1 for all other OSDs
+ *
+ * The lowest possible bucket type is 1, so the best locality
+ * for an OSD is 1 (i.e. a matching host).  Locality 0 would be
+ * the OSD itself.
+ */
+int ceph_get_crush_locality(struct ceph_osdmap *osdmap, int id,
+			    struct rb_root *locs)
+{
+	struct crush_loc loc;
+	u16 type_id;
+
+	/*
+	 * Instead of repeated get_immediate_parent() calls,
+	 * the location of @id could be obtained with a single
+	 * depth-first traversal.
+	 */
+	for (;;) {
+		id = get_immediate_parent(osdmap->crush, id, &type_id, &loc);
+		if (id >= 0)
+			return -1;  /* not local */
+
+		if (lookup_crush_loc(locs, &loc))
+			return type_id;
+	}
+}