Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1597 insertions, 0 deletions

diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c
new file mode 100644
index 000000000..c56457378
--- /dev/null
+++ b/net/ceph/mon_client.c
@@ -0,0 +1,1597 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+
+#include <linux/ceph/ceph_features.h>
+#include <linux/ceph/mon_client.h>
+#include <linux/ceph/libceph.h>
+#include <linux/ceph/debugfs.h>
+#include <linux/ceph/decode.h>
+#include <linux/ceph/auth.h>
+
+/*
+ * Interact with Ceph monitor cluster.  Handle requests for new map
+ * versions, and periodically resend as needed.  Also implement
+ * statfs() and umount().
+ *
+ * A small cluster of Ceph "monitors" are responsible for managing critical
+ * cluster configuration and state information.  An odd number (e.g., 3, 5)
+ * of cmon daemons use a modified version of the Paxos part-time parliament
+ * algorithm to manage the MDS map (mds cluster membership), OSD map, and
+ * list of clients who have mounted the file system.
+ *
+ * We maintain an open, active session with a monitor at all times in order to
+ * receive timely MDSMap updates.  We periodically send a keepalive byte on the
+ * TCP socket to ensure we detect a failure.  If the connection does break, we
+ * randomly hunt for a new monitor.  Once the connection is reestablished, we
+ * resend any outstanding requests.
+ */
+
+static const struct ceph_connection_operations mon_con_ops;
+
+static int __validate_auth(struct ceph_mon_client *monc);
+
+static int decode_mon_info(void **p, void *end, bool msgr2,
+			   struct ceph_entity_addr *addr)
+{
+	void *mon_info_end;
+	u32 struct_len;
+	u8 struct_v;
+	int ret;
+
+	ret = ceph_start_decoding(p, end, 1, "mon_info_t", &struct_v,
+				  &struct_len);
+	if (ret)
+		return ret;
+
+	mon_info_end = *p + struct_len;
+	ceph_decode_skip_string(p, end, e_inval);  /* skip mon name */
+	ret = ceph_decode_entity_addrvec(p, end, msgr2, addr);
+	if (ret)
+		return ret;
+
+	*p = mon_info_end;
+	return 0;
+
+e_inval:
+	return -EINVAL;
+}
+
+/*
+ * Decode a monmap blob (e.g., during mount).
+ *
+ * Assume MonMap v3 (i.e. encoding with MONNAMES and MONENC).
+ */
+static struct ceph_monmap *ceph_monmap_decode(void **p, void *end, bool msgr2)
+{
+	struct ceph_monmap *monmap = NULL;
+	struct ceph_fsid fsid;
+	u32 struct_len;
+	u32 blob_len;
+	u32 num_mon;
+	u8 struct_v;
+	u32 epoch;
+	int ret;
+	int i;
+
+	ceph_decode_32_safe(p, end, blob_len, e_inval);
+	ceph_decode_need(p, end, blob_len, e_inval);
+
+	ret = ceph_start_decoding(p, end, 6, "monmap", &struct_v, &struct_len);
+	if (ret)
+		goto fail;
+
+	dout("%s struct_v %d\n", __func__, struct_v);
+	ceph_decode_copy_safe(p, end, &fsid, sizeof(fsid), e_inval);
+	ceph_decode_32_safe(p, end, epoch, e_inval);
+	if (struct_v >= 6) {
+		u32 feat_struct_len;
+		u8 feat_struct_v;
+
+		*p += sizeof(struct ceph_timespec);  /* skip last_changed */
+		*p += sizeof(struct ceph_timespec);  /* skip created */
+
+		ret = ceph_start_decoding(p, end, 1, "mon_feature_t",
+					  &feat_struct_v, &feat_struct_len);
+		if (ret)
+			goto fail;
+
+		*p += feat_struct_len;  /* skip persistent_features */
+
+		ret = ceph_start_decoding(p, end, 1, "mon_feature_t",
+					  &feat_struct_v, &feat_struct_len);
+		if (ret)
+			goto fail;
+
+		*p += feat_struct_len;  /* skip optional_features */
+	}
+	ceph_decode_32_safe(p, end, num_mon, e_inval);
+
+	dout("%s fsid %pU epoch %u num_mon %u\n", __func__, &fsid, epoch,
+	     num_mon);
+	if (num_mon == 0 || num_mon > CEPH_MAX_MON)
+		goto e_inval;
+
+	monmap = kmalloc_flex(*monmap, mon_inst, num_mon, GFP_NOIO);
+	if (!monmap) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+	monmap->fsid = fsid;
+	monmap->epoch = epoch;
+	monmap->num_mon = num_mon;
+
+	/* legacy_mon_addr map or mon_info map */
+	for (i = 0; i < num_mon; i++) {
+		struct ceph_entity_inst *inst = &monmap->mon_inst[i];
+
+		ceph_decode_skip_string(p, end, e_inval);  /* skip mon name */
+		inst->name.type = CEPH_ENTITY_TYPE_MON;
+		inst->name.num = cpu_to_le64(i);
+
+		if (struct_v >= 6)
+			ret = decode_mon_info(p, end, msgr2, &inst->addr);
+		else
+			ret = ceph_decode_entity_addr(p, end, &inst->addr);
+		if (ret)
+			goto fail;
+
+		dout("%s mon%d addr %s\n", __func__, i,
+		     ceph_pr_addr(&inst->addr));
+	}
+
+	return monmap;
+
+e_inval:
+	ret = -EINVAL;
+fail:
+	kfree(monmap);
+	return ERR_PTR(ret);
+}
+
+/*
+ * return true if *addr is included in the monmap.
+ */
+int ceph_monmap_contains(struct ceph_monmap *m, struct ceph_entity_addr *addr)
+{
+	int i;
+
+	for (i = 0; i < m->num_mon; i++) {
+		if (ceph_addr_equal_no_type(addr, &m->mon_inst[i].addr))
+			return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * Send an auth request.
+ */
+static void __send_prepared_auth_request(struct ceph_mon_client *monc, int len)
+{
+	BUG_ON(len > monc->m_auth->front_alloc_len);
+
+	monc->pending_auth = 1;
+	monc->m_auth->front.iov_len = len;
+	monc->m_auth->hdr.front_len = cpu_to_le32(len);
+	ceph_msg_revoke(monc->m_auth);
+	ceph_msg_get(monc->m_auth);  /* keep our ref */
+	ceph_con_send(&monc->con, monc->m_auth);
+}
+
+/*
+ * Close monitor session, if any.
+ */
+static void __close_session(struct ceph_mon_client *monc)
+{
+	dout("__close_session closing mon%d\n", monc->cur_mon);
+	ceph_msg_revoke(monc->m_auth);
+	ceph_msg_revoke_incoming(monc->m_auth_reply);
+	ceph_msg_revoke(monc->m_subscribe);
+	ceph_msg_revoke_incoming(monc->m_subscribe_ack);
+	ceph_con_close(&monc->con);
+
+	monc->pending_auth = 0;
+	ceph_auth_reset(monc->auth);
+}
+
+/*
+ * Pick a new monitor at random and set cur_mon.  If we are repicking
+ * (i.e. cur_mon is already set), be sure to pick a different one.
+ */
+static void pick_new_mon(struct ceph_mon_client *monc)
+{
+	int old_mon = monc->cur_mon;
+
+	BUG_ON(monc->monmap->num_mon < 1);
+
+	if (monc->monmap->num_mon == 1) {
+		monc->cur_mon = 0;
+	} else {
+		int max = monc->monmap->num_mon;
+		int o = -1;
+		int n;
+
+		if (monc->cur_mon >= 0) {
+			if (monc->cur_mon < monc->monmap->num_mon)
+				o = monc->cur_mon;
+			if (o >= 0)
+				max--;
+		}
+
+		n = get_random_u32_below(max);
+		if (o >= 0 && n >= o)
+			n++;
+
+		monc->cur_mon = n;
+	}
+
+	dout("%s mon%d -> mon%d out of %d mons\n", __func__, old_mon,
+	     monc->cur_mon, monc->monmap->num_mon);
+}
+
+/*
+ * Open a session with a new monitor.
+ */
+static void __open_session(struct ceph_mon_client *monc)
+{
+	int ret;
+
+	pick_new_mon(monc);
+
+	monc->hunting = true;
+	if (monc->had_a_connection) {
+		monc->hunt_mult *= CEPH_MONC_HUNT_BACKOFF;
+		if (monc->hunt_mult > CEPH_MONC_HUNT_MAX_MULT)
+			monc->hunt_mult = CEPH_MONC_HUNT_MAX_MULT;
+	}
+
+	monc->sub_renew_after = jiffies; /* i.e., expired */
+	monc->sub_renew_sent = 0;
+
+	dout("%s opening mon%d\n", __func__, monc->cur_mon);
+	ceph_con_open(&monc->con, CEPH_ENTITY_TYPE_MON, monc->cur_mon,
+		      &monc->monmap->mon_inst[monc->cur_mon].addr);
+
+	/*
+	 * Queue a keepalive to ensure that in case of an early fault
+	 * the messenger doesn't put us into STANDBY state and instead
+	 * retries.  This also ensures that our timestamp is valid by
+	 * the time we finish hunting and delayed_work() checks it.
+	 */
+	ceph_con_keepalive(&monc->con);
+	if (ceph_msgr2(monc->client)) {
+		monc->pending_auth = 1;
+		return;
+	}
+
+	/* initiate authentication handshake */
+	ret = ceph_auth_build_hello(monc->auth,
+				    monc->m_auth->front.iov_base,
+				    monc->m_auth->front_alloc_len);
+	BUG_ON(ret <= 0);
+	__send_prepared_auth_request(monc, ret);
+}
+
+static void reopen_session(struct ceph_mon_client *monc)
+{
+	if (!monc->hunting)
+		pr_info("mon%d %s session lost, hunting for new mon\n",
+		    monc->cur_mon, ceph_pr_addr(&monc->con.peer_addr));
+
+	__close_session(monc);
+	__open_session(monc);
+}
+
+void ceph_monc_reopen_session(struct ceph_mon_client *monc)
+{
+	mutex_lock(&monc->mutex);
+	reopen_session(monc);
+	mutex_unlock(&monc->mutex);
+}
+
+static void un_backoff(struct ceph_mon_client *monc)
+{
+	monc->hunt_mult /= 2; /* reduce by 50% */
+	if (monc->hunt_mult < 1)
+		monc->hunt_mult = 1;
+	dout("%s hunt_mult now %d\n", __func__, monc->hunt_mult);
+}
+
+/*
+ * Reschedule delayed work timer.
+ */
+static void __schedule_delayed(struct ceph_mon_client *monc)
+{
+	unsigned long delay;
+
+	if (monc->hunting)
+		delay = CEPH_MONC_HUNT_INTERVAL * monc->hunt_mult;
+	else
+		delay = CEPH_MONC_PING_INTERVAL;
+
+	dout("__schedule_delayed after %lu\n", delay);
+	mod_delayed_work(system_percpu_wq, &monc->delayed_work,
+			 round_jiffies_relative(delay));
+}
+
+const char *ceph_sub_str[] = {
+	[CEPH_SUB_MONMAP] = "monmap",
+	[CEPH_SUB_OSDMAP] = "osdmap",
+	[CEPH_SUB_FSMAP]  = "fsmap.user",
+	[CEPH_SUB_MDSMAP] = "mdsmap",
+};
+
+/*
+ * Send subscribe request for one or more maps, according to
+ * monc->subs.
+ */
+static void __send_subscribe(struct ceph_mon_client *monc)
+{
+	struct ceph_msg *msg = monc->m_subscribe;
+	void *p = msg->front.iov_base;
+	void *const end = p + msg->front_alloc_len;
+	int num = 0;
+	int i;
+
+	dout("%s sent %lu\n", __func__, monc->sub_renew_sent);
+
+	BUG_ON(monc->cur_mon < 0);
+
+	if (!monc->sub_renew_sent)
+		monc->sub_renew_sent = jiffies | 1; /* never 0 */
+
+	msg->hdr.version = cpu_to_le16(2);
+
+	for (i = 0; i < ARRAY_SIZE(monc->subs); i++) {
+		if (monc->subs[i].want)
+			num++;
+	}
+	BUG_ON(num < 1); /* monmap sub is always there */
+	ceph_encode_32(&p, num);
+	for (i = 0; i < ARRAY_SIZE(monc->subs); i++) {
+		char buf[32];
+		int len;
+
+		if (!monc->subs[i].want)
+			continue;
+
+		len = sprintf(buf, "%s", ceph_sub_str[i]);
+		if (i == CEPH_SUB_MDSMAP &&
+		    monc->fs_cluster_id != CEPH_FS_CLUSTER_ID_NONE)
+			len += sprintf(buf + len, ".%d", monc->fs_cluster_id);
+
+		dout("%s %s start %llu flags 0x%x\n", __func__, buf,
+		     le64_to_cpu(monc->subs[i].item.start),
+		     monc->subs[i].item.flags);
+		ceph_encode_string(&p, end, buf, len);
+		memcpy(p, &monc->subs[i].item, sizeof(monc->subs[i].item));
+		p += sizeof(monc->subs[i].item);
+	}
+
+	BUG_ON(p > end);
+	msg->front.iov_len = p - msg->front.iov_base;
+	msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
+	ceph_msg_revoke(msg);
+	ceph_con_send(&monc->con, ceph_msg_get(msg));
+}
+
+static void handle_subscribe_ack(struct ceph_mon_client *monc,
+				 struct ceph_msg *msg)
+{
+	unsigned int seconds;
+	struct ceph_mon_subscribe_ack *h = msg->front.iov_base;
+
+	if (msg->front.iov_len < sizeof(*h))
+		goto bad;
+	seconds = le32_to_cpu(h->duration);
+
+	mutex_lock(&monc->mutex);
+	if (monc->sub_renew_sent) {
+		/*
+		 * This is only needed for legacy (infernalis or older)
+		 * MONs -- see delayed_work().
+		 */
+		monc->sub_renew_after = monc->sub_renew_sent +
+					    (seconds >> 1) * HZ - 1;
+		dout("%s sent %lu duration %d renew after %lu\n", __func__,
+		     monc->sub_renew_sent, seconds, monc->sub_renew_after);
+		monc->sub_renew_sent = 0;
+	} else {
+		dout("%s sent %lu renew after %lu, ignoring\n", __func__,
+		     monc->sub_renew_sent, monc->sub_renew_after);
+	}
+	mutex_unlock(&monc->mutex);
+	return;
+bad:
+	pr_err("got corrupt subscribe-ack msg\n");
+	ceph_msg_dump(msg);
+}
+
+/*
+ * Register interest in a map
+ *
+ * @sub: one of CEPH_SUB_*
+ * @epoch: X for "every map since X", or 0 for "just the latest"
+ */
+static bool __ceph_monc_want_map(struct ceph_mon_client *monc, int sub,
+				 u32 epoch, bool continuous)
+{
+	__le64 start = cpu_to_le64(epoch);
+	u8 flags = !continuous ? CEPH_SUBSCRIBE_ONETIME : 0;
+
+	dout("%s %s epoch %u continuous %d\n", __func__, ceph_sub_str[sub],
+	     epoch, continuous);
+
+	if (monc->subs[sub].want &&
+	    monc->subs[sub].item.start == start &&
+	    monc->subs[sub].item.flags == flags)
+		return false;
+
+	monc->subs[sub].item.start = start;
+	monc->subs[sub].item.flags = flags;
+	monc->subs[sub].want = true;
+
+	return true;
+}
+
+bool ceph_monc_want_map(struct ceph_mon_client *monc, int sub, u32 epoch,
+			bool continuous)
+{
+	bool need_request;
+
+	mutex_lock(&monc->mutex);
+	need_request = __ceph_monc_want_map(monc, sub, epoch, continuous);
+	mutex_unlock(&monc->mutex);
+
+	return need_request;
+}
+EXPORT_SYMBOL(ceph_monc_want_map);
+
+/*
+ * Keep track of which maps we have
+ *
+ * @sub: one of CEPH_SUB_*
+ */
+static void __ceph_monc_got_map(struct ceph_mon_client *monc, int sub,
+				u32 epoch)
+{
+	dout("%s %s epoch %u\n", __func__, ceph_sub_str[sub], epoch);
+
+	if (monc->subs[sub].want) {
+		if (monc->subs[sub].item.flags & CEPH_SUBSCRIBE_ONETIME)
+			monc->subs[sub].want = false;
+		else
+			monc->subs[sub].item.start = cpu_to_le64(epoch + 1);
+	}
+
+	monc->subs[sub].have = epoch;
+}
+
+void ceph_monc_got_map(struct ceph_mon_client *monc, int sub, u32 epoch)
+{
+	mutex_lock(&monc->mutex);
+	__ceph_monc_got_map(monc, sub, epoch);
+	mutex_unlock(&monc->mutex);
+}
+EXPORT_SYMBOL(ceph_monc_got_map);
+
+void ceph_monc_renew_subs(struct ceph_mon_client *monc)
+{
+	mutex_lock(&monc->mutex);
+	__send_subscribe(monc);
+	mutex_unlock(&monc->mutex);
+}
+EXPORT_SYMBOL(ceph_monc_renew_subs);
+
+/*
+ * Wait for an osdmap with a given epoch.
+ *
+ * @epoch: epoch to wait for
+ * @timeout: in jiffies, 0 means "wait forever"
+ */
+int ceph_monc_wait_osdmap(struct ceph_mon_client *monc, u32 epoch,
+			  unsigned long timeout)
+{
+	unsigned long started = jiffies;
+	long ret;
+
+	mutex_lock(&monc->mutex);
+	while (monc->subs[CEPH_SUB_OSDMAP].have < epoch) {
+		mutex_unlock(&monc->mutex);
+
+		if (timeout && time_after_eq(jiffies, started + timeout))
+			return -ETIMEDOUT;
+
+		ret = wait_event_interruptible_timeout(monc->client->auth_wq,
+				     monc->subs[CEPH_SUB_OSDMAP].have >= epoch,
+				     ceph_timeout_jiffies(timeout));
+		if (ret < 0)
+			return ret;
+
+		mutex_lock(&monc->mutex);
+	}
+
+	mutex_unlock(&monc->mutex);
+	return 0;
+}
+EXPORT_SYMBOL(ceph_monc_wait_osdmap);
+
+/*
+ * Open a session with a random monitor.  Request monmap and osdmap,
+ * which are waited upon in __ceph_open_session().
+ */
+int ceph_monc_open_session(struct ceph_mon_client *monc)
+{
+	mutex_lock(&monc->mutex);
+	__ceph_monc_want_map(monc, CEPH_SUB_MONMAP, 0, true);
+	__ceph_monc_want_map(monc, CEPH_SUB_OSDMAP, 0, false);
+	__open_session(monc);
+	__schedule_delayed(monc);
+	mutex_unlock(&monc->mutex);
+	return 0;
+}
+EXPORT_SYMBOL(ceph_monc_open_session);
+
+static void ceph_monc_handle_map(struct ceph_mon_client *monc,
+				 struct ceph_msg *msg)
+{
+	struct ceph_client *client = monc->client;
+	struct ceph_monmap *monmap;
+	void *p, *end;
+
+	mutex_lock(&monc->mutex);
+
+	dout("handle_monmap\n");
+	p = msg->front.iov_base;
+	end = p + msg->front.iov_len;
+
+	monmap = ceph_monmap_decode(&p, end, ceph_msgr2(client));
+	if (IS_ERR(monmap)) {
+		pr_err("problem decoding monmap, %d\n",
+		       (int)PTR_ERR(monmap));
+		ceph_msg_dump(msg);
+		goto out;
+	}
+
+	if (ceph_check_fsid(client, &monmap->fsid) < 0) {
+		kfree(monmap);
+		goto out;
+	}
+
+	kfree(monc->monmap);
+	monc->monmap = monmap;
+
+	__ceph_monc_got_map(monc, CEPH_SUB_MONMAP, monc->monmap->epoch);
+	client->have_fsid = true;
+
+out:
+	mutex_unlock(&monc->mutex);
+	wake_up_all(&client->auth_wq);
+}
+
+/*
+ * generic requests (currently statfs, mon_get_version)
+ */
+DEFINE_RB_FUNCS(generic_request, struct ceph_mon_generic_request, tid, node)
+
+static void release_generic_request(struct kref *kref)
+{
+	struct ceph_mon_generic_request *req =
+		container_of(kref, struct ceph_mon_generic_request, kref);
+
+	dout("%s greq %p request %p reply %p\n", __func__, req, req->request,
+	     req->reply);
+	WARN_ON(!RB_EMPTY_NODE(&req->node));
+
+	if (req->reply)
+		ceph_msg_put(req->reply);
+	if (req->request)
+		ceph_msg_put(req->request);
+
+	kfree(req);
+}
+
+static void put_generic_request(struct ceph_mon_generic_request *req)
+{
+	if (req)
+		kref_put(&req->kref, release_generic_request);
+}
+
+static void get_generic_request(struct ceph_mon_generic_request *req)
+{
+	kref_get(&req->kref);
+}
+
+static struct ceph_mon_generic_request *
+alloc_generic_request(struct ceph_mon_client *monc, gfp_t gfp)
+{
+	struct ceph_mon_generic_request *req;
+
+	req = kzalloc_obj(*req, gfp);
+	if (!req)
+		return NULL;
+
+	req->monc = monc;
+	kref_init(&req->kref);
+	RB_CLEAR_NODE(&req->node);
+	init_completion(&req->completion);
+
+	dout("%s greq %p\n", __func__, req);
+	return req;
+}
+
+static void register_generic_request(struct ceph_mon_generic_request *req)
+{
+	struct ceph_mon_client *monc = req->monc;
+
+	WARN_ON(req->tid);
+
+	get_generic_request(req);
+	req->tid = ++monc->last_tid;
+	insert_generic_request(&monc->generic_request_tree, req);
+}
+
+static void send_generic_request(struct ceph_mon_client *monc,
+				 struct ceph_mon_generic_request *req)
+{
+	WARN_ON(!req->tid);
+
+	dout("%s greq %p tid %llu\n", __func__, req, req->tid);
+	req->request->hdr.tid = cpu_to_le64(req->tid);
+	ceph_con_send(&monc->con, ceph_msg_get(req->request));
+}
+
+static void __finish_generic_request(struct ceph_mon_generic_request *req)
+{
+	struct ceph_mon_client *monc = req->monc;
+
+	dout("%s greq %p tid %llu\n", __func__, req, req->tid);
+	erase_generic_request(&monc->generic_request_tree, req);
+
+	ceph_msg_revoke(req->request);
+	ceph_msg_revoke_incoming(req->reply);
+}
+
+static void finish_generic_request(struct ceph_mon_generic_request *req)
+{
+	__finish_generic_request(req);
+	put_generic_request(req);
+}
+
+static void complete_generic_request(struct ceph_mon_generic_request *req)
+{
+	if (req->complete_cb)
+		req->complete_cb(req);
+	else
+		complete_all(&req->completion);
+	put_generic_request(req);
+}
+
+static void cancel_generic_request(struct ceph_mon_generic_request *req)
+{
+	struct ceph_mon_client *monc = req->monc;
+	struct ceph_mon_generic_request *lookup_req;
+
+	dout("%s greq %p tid %llu\n", __func__, req, req->tid);
+
+	mutex_lock(&monc->mutex);
+	lookup_req = lookup_generic_request(&monc->generic_request_tree,
+					    req->tid);
+	if (lookup_req) {
+		WARN_ON(lookup_req != req);
+		finish_generic_request(req);
+	}
+
+	mutex_unlock(&monc->mutex);
+}
+
+static int wait_generic_request(struct ceph_mon_generic_request *req)
+{
+	int ret;
+
+	dout("%s greq %p tid %llu\n", __func__, req, req->tid);
+	ret = wait_for_completion_interruptible(&req->completion);
+	if (ret)
+		cancel_generic_request(req);
+	else
+		ret = req->result; /* completed */
+
+	return ret;
+}
+
+static struct ceph_msg *get_generic_reply(struct ceph_connection *con,
+					 struct ceph_msg_header *hdr,
+					 int *skip)
+{
+	struct ceph_mon_client *monc = con->private;
+	struct ceph_mon_generic_request *req;
+	u64 tid = le64_to_cpu(hdr->tid);
+	struct ceph_msg *m;
+
+	mutex_lock(&monc->mutex);
+	req = lookup_generic_request(&monc->generic_request_tree, tid);
+	if (!req) {
+		dout("get_generic_reply %lld dne\n", tid);
+		*skip = 1;
+		m = NULL;
+	} else {
+		dout("get_generic_reply %lld got %p\n", tid, req->reply);
+		*skip = 0;
+		m = ceph_msg_get(req->reply);
+		/*
+		 * we don't need to track the connection reading into
+		 * this reply because we only have one open connection
+		 * at a time, ever.
+		 */
+	}
+	mutex_unlock(&monc->mutex);
+	return m;
+}
+
+/*
+ * statfs
+ */
+static void handle_statfs_reply(struct ceph_mon_client *monc,
+				struct ceph_msg *msg)
+{
+	struct ceph_mon_generic_request *req;
+	struct ceph_mon_statfs_reply *reply = msg->front.iov_base;
+	u64 tid = le64_to_cpu(msg->hdr.tid);
+
+	dout("%s msg %p tid %llu\n", __func__, msg, tid);
+
+	if (msg->front.iov_len != sizeof(*reply))
+		goto bad;
+
+	mutex_lock(&monc->mutex);
+	req = lookup_generic_request(&monc->generic_request_tree, tid);
+	if (!req) {
+		mutex_unlock(&monc->mutex);
+		return;
+	}
+
+	req->result = 0;
+	*req->u.st = reply->st; /* struct */
+	__finish_generic_request(req);
+	mutex_unlock(&monc->mutex);
+
+	complete_generic_request(req);
+	return;
+
+bad:
+	pr_err("corrupt statfs reply, tid %llu\n", tid);
+	ceph_msg_dump(msg);
+}
+
+/*
+ * Do a synchronous statfs().
+ */
+int ceph_monc_do_statfs(struct ceph_mon_client *monc, u64 data_pool,
+			struct ceph_statfs *buf)
+{
+	struct ceph_mon_generic_request *req;
+	struct ceph_mon_statfs *h;
+	int ret = -ENOMEM;
+
+	req = alloc_generic_request(monc, GFP_NOFS);
+	if (!req)
+		goto out;
+
+	req->request = ceph_msg_new(CEPH_MSG_STATFS, sizeof(*h), GFP_NOFS,
+				    true);
+	if (!req->request)
+		goto out;
+
+	req->reply = ceph_msg_new(CEPH_MSG_STATFS_REPLY, 64, GFP_NOFS, true);
+	if (!req->reply)
+		goto out;
+
+	req->u.st = buf;
+	req->request->hdr.version = cpu_to_le16(2);
+
+	mutex_lock(&monc->mutex);
+	register_generic_request(req);
+	/* fill out request */
+	h = req->request->front.iov_base;
+	h->monhdr.have_version = 0;
+	h->monhdr.session_mon = cpu_to_le16(-1);
+	h->monhdr.session_mon_tid = 0;
+	h->fsid = monc->monmap->fsid;
+	h->contains_data_pool = (data_pool != CEPH_NOPOOL);
+	h->data_pool = cpu_to_le64(data_pool);
+	send_generic_request(monc, req);
+	mutex_unlock(&monc->mutex);
+
+	ret = wait_generic_request(req);
+out:
+	put_generic_request(req);
+	return ret;
+}
+EXPORT_SYMBOL(ceph_monc_do_statfs);
+
+static void handle_get_version_reply(struct ceph_mon_client *monc,
+				     struct ceph_msg *msg)
+{
+	struct ceph_mon_generic_request *req;
+	u64 tid = le64_to_cpu(msg->hdr.tid);
+	void *p = msg->front.iov_base;
+	void *const end = p + msg->front.iov_len;
+	u64 handle;
+
+	dout("%s msg %p tid %llu\n", __func__, msg, tid);
+
+	ceph_decode_need(&p, end, 2*sizeof(u64), bad);
+	handle = ceph_decode_64(&p);
+	if (tid != 0 && tid != handle)
+		goto bad;
+
+	mutex_lock(&monc->mutex);
+	req = lookup_generic_request(&monc->generic_request_tree, handle);
+	if (!req) {
+		mutex_unlock(&monc->mutex);
+		return;
+	}
+
+	req->result = 0;
+	req->u.newest = ceph_decode_64(&p);
+	__finish_generic_request(req);
+	mutex_unlock(&monc->mutex);
+
+	complete_generic_request(req);
+	return;
+
+bad:
+	pr_err("corrupt mon_get_version reply, tid %llu\n", tid);
+	ceph_msg_dump(msg);
+}
+
+static struct ceph_mon_generic_request *
+__ceph_monc_get_version(struct ceph_mon_client *monc, const char *what,
+			ceph_monc_callback_t cb, u64 private_data)
+{
+	struct ceph_mon_generic_request *req;
+
+	req = alloc_generic_request(monc, GFP_NOIO);
+	if (!req)
+		goto err_put_req;
+
+	req->request = ceph_msg_new(CEPH_MSG_MON_GET_VERSION,
+				    sizeof(u64) + sizeof(u32) + strlen(what),
+				    GFP_NOIO, true);
+	if (!req->request)
+		goto err_put_req;
+
+	req->reply = ceph_msg_new(CEPH_MSG_MON_GET_VERSION_REPLY, 32, GFP_NOIO,
+				  true);
+	if (!req->reply)
+		goto err_put_req;
+
+	req->complete_cb = cb;
+	req->private_data = private_data;
+
+	mutex_lock(&monc->mutex);
+	register_generic_request(req);
+	{
+		void *p = req->request->front.iov_base;
+		void *const end = p + req->request->front_alloc_len;
+
+		ceph_encode_64(&p, req->tid); /* handle */
+		ceph_encode_string(&p, end, what, strlen(what));
+		WARN_ON(p != end);
+	}
+	send_generic_request(monc, req);
+	mutex_unlock(&monc->mutex);
+
+	return req;
+
+err_put_req:
+	put_generic_request(req);
+	return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * Send MMonGetVersion and wait for the reply.
+ *
+ * @what: one of "mdsmap", "osdmap" or "monmap"
+ */
+int ceph_monc_get_version(struct ceph_mon_client *monc, const char *what,
+			  u64 *newest)
+{
+	struct ceph_mon_generic_request *req;
+	int ret;
+
+	req = __ceph_monc_get_version(monc, what, NULL, 0);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	ret = wait_generic_request(req);
+	if (!ret)
+		*newest = req->u.newest;
+
+	put_generic_request(req);
+	return ret;
+}
+EXPORT_SYMBOL(ceph_monc_get_version);
+
+/*
+ * Send MMonGetVersion,
+ *
+ * @what: one of "mdsmap", "osdmap" or "monmap"
+ */
+int ceph_monc_get_version_async(struct ceph_mon_client *monc, const char *what,
+				ceph_monc_callback_t cb, u64 private_data)
+{
+	struct ceph_mon_generic_request *req;
+
+	req = __ceph_monc_get_version(monc, what, cb, private_data);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	put_generic_request(req);
+	return 0;
+}
+EXPORT_SYMBOL(ceph_monc_get_version_async);
+
+static void handle_command_ack(struct ceph_mon_client *monc,
+			       struct ceph_msg *msg)
+{
+	struct ceph_mon_generic_request *req;
+	void *p = msg->front.iov_base;
+	void *const end = p + msg->front_alloc_len;
+	u64 tid = le64_to_cpu(msg->hdr.tid);
+
+	dout("%s msg %p tid %llu\n", __func__, msg, tid);
+
+	ceph_decode_need(&p, end, sizeof(struct ceph_mon_request_header) +
+							    sizeof(u32), bad);
+	p += sizeof(struct ceph_mon_request_header);
+
+	mutex_lock(&monc->mutex);
+	req = lookup_generic_request(&monc->generic_request_tree, tid);
+	if (!req) {
+		mutex_unlock(&monc->mutex);
+		return;
+	}
+
+	req->result = ceph_decode_32(&p);
+	__finish_generic_request(req);
+	mutex_unlock(&monc->mutex);
+
+	complete_generic_request(req);
+	return;
+
+bad:
+	pr_err("corrupt mon_command ack, tid %llu\n", tid);
+	ceph_msg_dump(msg);
+}
+
+static __printf(2, 0)
+int do_mon_command_vargs(struct ceph_mon_client *monc, const char *fmt,
+			 va_list ap)
+{
+	struct ceph_mon_generic_request *req;
+	struct ceph_mon_command *h;
+	int ret = -ENOMEM;
+	int len;
+
+	req = alloc_generic_request(monc, GFP_NOIO);
+	if (!req)
+		goto out;
+
+	req->request = ceph_msg_new(CEPH_MSG_MON_COMMAND, 256, GFP_NOIO, true);
+	if (!req->request)
+		goto out;
+
+	req->reply = ceph_msg_new(CEPH_MSG_MON_COMMAND_ACK, 512, GFP_NOIO,
+				  true);
+	if (!req->reply)
+		goto out;
+
+	mutex_lock(&monc->mutex);
+	register_generic_request(req);
+	h = req->request->front.iov_base;
+	h->monhdr.have_version = 0;
+	h->monhdr.session_mon = cpu_to_le16(-1);
+	h->monhdr.session_mon_tid = 0;
+	h->fsid = monc->monmap->fsid;
+	h->num_strs = cpu_to_le32(1);
+	len = vsprintf(h->str, fmt, ap);
+	h->str_len = cpu_to_le32(len);
+	send_generic_request(monc, req);
+	mutex_unlock(&monc->mutex);
+
+	ret = wait_generic_request(req);
+out:
+	put_generic_request(req);
+	return ret;
+}
+
+static __printf(2, 3)
+int do_mon_command(struct ceph_mon_client *monc, const char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, fmt);
+	ret = do_mon_command_vargs(monc, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+int ceph_monc_blocklist_add(struct ceph_mon_client *monc,
+			    struct ceph_entity_addr *client_addr)
+{
+	int ret;
+
+	ret = do_mon_command(monc,
+			     "{ \"prefix\": \"osd blocklist\", \
+				\"blocklistop\": \"add\", \
+				\"addr\": \"%pISpc/%u\" }",
+			     &client_addr->in_addr,
+			     le32_to_cpu(client_addr->nonce));
+	if (ret == -EINVAL) {
+		/*
+		 * The monitor returns EINVAL on an unrecognized command.
+		 * Try the legacy command -- it is exactly the same except
+		 * for the name.
+		 */
+		ret = do_mon_command(monc,
+				     "{ \"prefix\": \"osd blacklist\", \
+					\"blacklistop\": \"add\", \
+					\"addr\": \"%pISpc/%u\" }",
+				     &client_addr->in_addr,
+				     le32_to_cpu(client_addr->nonce));
+	}
+	if (ret)
+		return ret;
+
+	/*
+	 * Make sure we have the osdmap that includes the blocklist
+	 * entry.  This is needed to ensure that the OSDs pick up the
+	 * new blocklist before processing any future requests from
+	 * this client.
+	 */
+	return ceph_wait_for_latest_osdmap(monc->client, 0);
+}
+EXPORT_SYMBOL(ceph_monc_blocklist_add);
+
+/*
+ * Resend pending generic requests.
+ */
+static void __resend_generic_request(struct ceph_mon_client *monc)
+{
+	struct ceph_mon_generic_request *req;
+	struct rb_node *p;
+
+	for (p = rb_first(&monc->generic_request_tree); p; p = rb_next(p)) {
+		req = rb_entry(p, struct ceph_mon_generic_request, node);
+		ceph_msg_revoke(req->request);
+		ceph_msg_revoke_incoming(req->reply);
+		ceph_con_send(&monc->con, ceph_msg_get(req->request));
+	}
+}
+
+/*
+ * Delayed work.  If we haven't mounted yet, retry.  Otherwise,
+ * renew/retry subscription as needed (in case it is timing out, or we
+ * got an ENOMEM).  And keep the monitor connection alive.
+ */
+static void delayed_work(struct work_struct *work)
+{
+	struct ceph_mon_client *monc =
+		container_of(work, struct ceph_mon_client, delayed_work.work);
+
+	mutex_lock(&monc->mutex);
+	dout("%s mon%d\n", __func__, monc->cur_mon);
+	if (monc->cur_mon < 0) {
+		goto out;
+	}
+
+	if (monc->hunting) {
+		dout("%s continuing hunt\n", __func__);
+		reopen_session(monc);
+	} else {
+		int is_auth = ceph_auth_is_authenticated(monc->auth);
+
+		dout("%s is_authed %d\n", __func__, is_auth);
+		if (ceph_con_keepalive_expired(&monc->con,
+					       CEPH_MONC_PING_TIMEOUT)) {
+			dout("monc keepalive timeout\n");
+			is_auth = 0;
+			reopen_session(monc);
+		}
+
+		if (!monc->hunting) {
+			ceph_con_keepalive(&monc->con);
+			__validate_auth(monc);
+			un_backoff(monc);
+		}
+
+		if (is_auth &&
+		    !(monc->con.peer_features & CEPH_FEATURE_MON_STATEFUL_SUB)) {
+			unsigned long now = jiffies;
+
+			dout("%s renew subs? now %lu renew after %lu\n",
+			     __func__, now, monc->sub_renew_after);
+			if (time_after_eq(now, monc->sub_renew_after))
+				__send_subscribe(monc);
+		}
+	}
+	__schedule_delayed(monc);
+
+out:
+	mutex_unlock(&monc->mutex);
+}
+
+/*
+ * On startup, we build a temporary monmap populated with the IPs
+ * provided by mount(2).
+ */
+static int build_initial_monmap(struct ceph_mon_client *monc)
+{
+	__le32 my_type = ceph_msgr2(monc->client) ?
+		CEPH_ENTITY_ADDR_TYPE_MSGR2 : CEPH_ENTITY_ADDR_TYPE_LEGACY;
+	struct ceph_options *opt = monc->client->options;
+	int num_mon = opt->num_mon;
+	int i;
+
+	/* build initial monmap */
+	monc->monmap = kzalloc_flex(*monc->monmap, mon_inst, num_mon);
+	if (!monc->monmap)
+		return -ENOMEM;
+	monc->monmap->num_mon = num_mon;
+
+	for (i = 0; i < num_mon; i++) {
+		struct ceph_entity_inst *inst = &monc->monmap->mon_inst[i];
+
+		memcpy(&inst->addr.in_addr, &opt->mon_addr[i].in_addr,
+		       sizeof(inst->addr.in_addr));
+		inst->addr.type = my_type;
+		inst->addr.nonce = 0;
+		inst->name.type = CEPH_ENTITY_TYPE_MON;
+		inst->name.num = cpu_to_le64(i);
+	}
+	return 0;
+}
+
+int ceph_monc_init(struct ceph_mon_client *monc, struct ceph_client *cl)
+{
+	int err;
+
+	dout("init\n");
+	memset(monc, 0, sizeof(*monc));
+	monc->client = cl;
+	mutex_init(&monc->mutex);
+
+	err = build_initial_monmap(monc);
+	if (err)
+		goto out;
+
+	/* connection */
+	/* authentication */
+	monc->auth = ceph_auth_init(cl->options->name, cl->options->key,
+				    cl->options->con_modes);
+	if (IS_ERR(monc->auth)) {
+		err = PTR_ERR(monc->auth);
+		goto out_monmap;
+	}
+	monc->auth->want_keys =
+		CEPH_ENTITY_TYPE_AUTH | CEPH_ENTITY_TYPE_MON |
+		CEPH_ENTITY_TYPE_OSD | CEPH_ENTITY_TYPE_MDS;
+
+	/* msgs */
+	err = -ENOMEM;
+	monc->m_subscribe_ack = ceph_msg_new(CEPH_MSG_MON_SUBSCRIBE_ACK,
+				     sizeof(struct ceph_mon_subscribe_ack),
+				     GFP_KERNEL, true);
+	if (!monc->m_subscribe_ack)
+		goto out_auth;
+
+	monc->m_subscribe = ceph_msg_new(CEPH_MSG_MON_SUBSCRIBE, 128,
+					 GFP_KERNEL, true);
+	if (!monc->m_subscribe)
+		goto out_subscribe_ack;
+
+	monc->m_auth_reply = ceph_msg_new(CEPH_MSG_AUTH_REPLY, 4096,
+					  GFP_KERNEL, true);
+	if (!monc->m_auth_reply)
+		goto out_subscribe;
+
+	monc->m_auth = ceph_msg_new(CEPH_MSG_AUTH, 4096, GFP_KERNEL, true);
+	monc->pending_auth = 0;
+	if (!monc->m_auth)
+		goto out_auth_reply;
+
+	ceph_con_init(&monc->con, monc, &mon_con_ops,
+		      &monc->client->msgr);
+
+	monc->cur_mon = -1;
+	monc->had_a_connection = false;
+	monc->hunt_mult = 1;
+
+	INIT_DELAYED_WORK(&monc->delayed_work, delayed_work);
+	monc->generic_request_tree = RB_ROOT;
+	monc->last_tid = 0;
+
+	monc->fs_cluster_id = CEPH_FS_CLUSTER_ID_NONE;
+
+	return 0;
+
+out_auth_reply:
+	ceph_msg_put(monc->m_auth_reply);
+out_subscribe:
+	ceph_msg_put(monc->m_subscribe);
+out_subscribe_ack:
+	ceph_msg_put(monc->m_subscribe_ack);
+out_auth:
+	ceph_auth_destroy(monc->auth);
+out_monmap:
+	kfree(monc->monmap);
+out:
+	return err;
+}
+EXPORT_SYMBOL(ceph_monc_init);
+
+void ceph_monc_stop(struct ceph_mon_client *monc)
+{
+	dout("stop\n");
+
+	mutex_lock(&monc->mutex);
+	__close_session(monc);
+	monc->hunting = false;
+	monc->cur_mon = -1;
+	mutex_unlock(&monc->mutex);
+
+	cancel_delayed_work_sync(&monc->delayed_work);
+
+	/*
+	 * flush msgr queue before we destroy ourselves to ensure that:
+	 *  - any work that references our embedded con is finished.
+	 *  - any osd_client or other work that may reference an authorizer
+	 *    finishes before we shut down the auth subsystem.
+	 */
+	ceph_msgr_flush();
+
+	ceph_auth_destroy(monc->auth);
+
+	WARN_ON(!RB_EMPTY_ROOT(&monc->generic_request_tree));
+
+	ceph_msg_put(monc->m_auth);
+	ceph_msg_put(monc->m_auth_reply);
+	ceph_msg_put(monc->m_subscribe);
+	ceph_msg_put(monc->m_subscribe_ack);
+
+	kfree(monc->monmap);
+}
+EXPORT_SYMBOL(ceph_monc_stop);
+
+static void finish_hunting(struct ceph_mon_client *monc)
+{
+	if (monc->hunting) {
+		dout("%s found mon%d\n", __func__, monc->cur_mon);
+		monc->hunting = false;
+		monc->had_a_connection = true;
+		un_backoff(monc);
+		__schedule_delayed(monc);
+	}
+}
+
+static void finish_auth(struct ceph_mon_client *monc, int auth_err,
+			bool was_authed)
+{
+	dout("%s auth_err %d was_authed %d\n", __func__, auth_err, was_authed);
+	WARN_ON(auth_err > 0);
+
+	monc->pending_auth = 0;
+	if (auth_err) {
+		monc->client->auth_err = auth_err;
+		wake_up_all(&monc->client->auth_wq);
+		return;
+	}
+
+	if (!was_authed && ceph_auth_is_authenticated(monc->auth)) {
+		dout("%s authenticated, starting session global_id %llu\n",
+		     __func__, monc->auth->global_id);
+
+		monc->client->msgr.inst.name.type = CEPH_ENTITY_TYPE_CLIENT;
+		monc->client->msgr.inst.name.num =
+					cpu_to_le64(monc->auth->global_id);
+
+		__send_subscribe(monc);
+		__resend_generic_request(monc);
+
+		pr_info("mon%d %s session established\n", monc->cur_mon,
+			ceph_pr_addr(&monc->con.peer_addr));
+	}
+}
+
+static void handle_auth_reply(struct ceph_mon_client *monc,
+			      struct ceph_msg *msg)
+{
+	bool was_authed;
+	int ret;
+
+	mutex_lock(&monc->mutex);
+	was_authed = ceph_auth_is_authenticated(monc->auth);
+	ret = ceph_handle_auth_reply(monc->auth, msg->front.iov_base,
+				     msg->front.iov_len,
+				     monc->m_auth->front.iov_base,
+				     monc->m_auth->front_alloc_len);
+	if (ret > 0) {
+		__send_prepared_auth_request(monc, ret);
+	} else {
+		finish_auth(monc, ret, was_authed);
+		finish_hunting(monc);
+	}
+	mutex_unlock(&monc->mutex);
+}
+
+static int __validate_auth(struct ceph_mon_client *monc)
+{
+	int ret;
+
+	if (monc->pending_auth)
+		return 0;
+
+	ret = ceph_build_auth(monc->auth, monc->m_auth->front.iov_base,
+			      monc->m_auth->front_alloc_len);
+	if (ret <= 0)
+		return ret; /* either an error, or no need to authenticate */
+	__send_prepared_auth_request(monc, ret);
+	return 0;
+}
+
+int ceph_monc_validate_auth(struct ceph_mon_client *monc)
+{
+	int ret;
+
+	mutex_lock(&monc->mutex);
+	ret = __validate_auth(monc);
+	mutex_unlock(&monc->mutex);
+	return ret;
+}
+EXPORT_SYMBOL(ceph_monc_validate_auth);
+
+static int mon_get_auth_request(struct ceph_connection *con,
+				void *buf, int *buf_len,
+				void **authorizer, int *authorizer_len)
+{
+	struct ceph_mon_client *monc = con->private;
+	int ret;
+
+	mutex_lock(&monc->mutex);
+	ret = ceph_auth_get_request(monc->auth, buf, *buf_len);
+	mutex_unlock(&monc->mutex);
+	if (ret < 0)
+		return ret;
+
+	*buf_len = ret;
+	*authorizer = NULL;
+	*authorizer_len = 0;
+	return 0;
+}
+
+static int mon_handle_auth_reply_more(struct ceph_connection *con,
+				      void *reply, int reply_len,
+				      void *buf, int *buf_len,
+				      void **authorizer, int *authorizer_len)
+{
+	struct ceph_mon_client *monc = con->private;
+	int ret;
+
+	mutex_lock(&monc->mutex);
+	ret = ceph_auth_handle_reply_more(monc->auth, reply, reply_len,
+					  buf, *buf_len);
+	mutex_unlock(&monc->mutex);
+	if (ret < 0)
+		return ret;
+
+	*buf_len = ret;
+	*authorizer = NULL;
+	*authorizer_len = 0;
+	return 0;
+}
+
+static int mon_handle_auth_done(struct ceph_connection *con,
+				u64 global_id, void *reply, int reply_len,
+				u8 *session_key, int *session_key_len,
+				u8 *con_secret, int *con_secret_len)
+{
+	struct ceph_mon_client *monc = con->private;
+	bool was_authed;
+	int ret;
+
+	mutex_lock(&monc->mutex);
+	WARN_ON(!monc->hunting);
+	was_authed = ceph_auth_is_authenticated(monc->auth);
+	ret = ceph_auth_handle_reply_done(monc->auth, global_id,
+					  reply, reply_len,
+					  session_key, session_key_len,
+					  con_secret, con_secret_len);
+	finish_auth(monc, ret, was_authed);
+	if (!ret)
+		finish_hunting(monc);
+	mutex_unlock(&monc->mutex);
+	return ret;
+}
+
+static int mon_handle_auth_bad_method(struct ceph_connection *con,
+				      int used_proto, int result,
+				      const int *allowed_protos, int proto_cnt,
+				      const int *allowed_modes, int mode_cnt)
+{
+	struct ceph_mon_client *monc = con->private;
+	bool was_authed;
+
+	mutex_lock(&monc->mutex);
+	WARN_ON(!monc->hunting);
+	was_authed = ceph_auth_is_authenticated(monc->auth);
+	ceph_auth_handle_bad_method(monc->auth, used_proto, result,
+				    allowed_protos, proto_cnt,
+				    allowed_modes, mode_cnt);
+	finish_auth(monc, -EACCES, was_authed);
+	mutex_unlock(&monc->mutex);
+	return 0;
+}
+
+/*
+ * handle incoming message
+ */
+static void mon_dispatch(struct ceph_connection *con, struct ceph_msg *msg)
+{
+	struct ceph_mon_client *monc = con->private;
+	int type = le16_to_cpu(msg->hdr.type);
+
+	switch (type) {
+	case CEPH_MSG_AUTH_REPLY:
+		handle_auth_reply(monc, msg);
+		break;
+
+	case CEPH_MSG_MON_SUBSCRIBE_ACK:
+		handle_subscribe_ack(monc, msg);
+		break;
+
+	case CEPH_MSG_STATFS_REPLY:
+		handle_statfs_reply(monc, msg);
+		break;
+
+	case CEPH_MSG_MON_GET_VERSION_REPLY:
+		handle_get_version_reply(monc, msg);
+		break;
+
+	case CEPH_MSG_MON_COMMAND_ACK:
+		handle_command_ack(monc, msg);
+		break;
+
+	case CEPH_MSG_MON_MAP:
+		ceph_monc_handle_map(monc, msg);
+		break;
+
+	case CEPH_MSG_OSD_MAP:
+		ceph_osdc_handle_map(&monc->client->osdc, msg);
+		break;
+
+	default:
+		/* can the chained handler handle it? */
+		if (monc->client->extra_mon_dispatch &&
+		    monc->client->extra_mon_dispatch(monc->client, msg) == 0)
+			break;
+
+		pr_err("received unknown message type %d %s\n", type,
+		       ceph_msg_type_name(type));
+	}
+	ceph_msg_put(msg);
+}
+
+/*
+ * Allocate memory for incoming message
+ */
+static struct ceph_msg *mon_alloc_msg(struct ceph_connection *con,
+				      struct ceph_msg_header *hdr,
+				      int *skip)
+{
+	struct ceph_mon_client *monc = con->private;
+	int type = le16_to_cpu(hdr->type);
+	int front_len = le32_to_cpu(hdr->front_len);
+	struct ceph_msg *m = NULL;
+
+	*skip = 0;
+
+	switch (type) {
+	case CEPH_MSG_MON_SUBSCRIBE_ACK:
+		m = ceph_msg_get(monc->m_subscribe_ack);
+		break;
+	case CEPH_MSG_STATFS_REPLY:
+	case CEPH_MSG_MON_COMMAND_ACK:
+		return get_generic_reply(con, hdr, skip);
+	case CEPH_MSG_AUTH_REPLY:
+		m = ceph_msg_get(monc->m_auth_reply);
+		break;
+	case CEPH_MSG_MON_GET_VERSION_REPLY:
+		if (le64_to_cpu(hdr->tid) != 0)
+			return get_generic_reply(con, hdr, skip);
+
+		/*
+		 * Older OSDs don't set reply tid even if the original
+		 * request had a non-zero tid.  Work around this weirdness
+		 * by allocating a new message.
+		 */
+		fallthrough;
+	case CEPH_MSG_MON_MAP:
+	case CEPH_MSG_MDS_MAP:
+	case CEPH_MSG_OSD_MAP:
+	case CEPH_MSG_FS_MAP_USER:
+		m = ceph_msg_new(type, front_len, GFP_NOFS, false);
+		if (!m)
+			return NULL;	/* ENOMEM--return skip == 0 */
+		break;
+	}
+
+	if (!m) {
+		pr_info("alloc_msg unknown type %d\n", type);
+		*skip = 1;
+	} else if (front_len > m->front_alloc_len) {
+		pr_warn("mon_alloc_msg front %d > prealloc %d (%u#%llu)\n",
+			front_len, m->front_alloc_len,
+			(unsigned int)con->peer_name.type,
+			le64_to_cpu(con->peer_name.num));
+		ceph_msg_put(m);
+		m = ceph_msg_new(type, front_len, GFP_NOFS, false);
+	}
+
+	return m;
+}
+
+/*
+ * If the monitor connection resets, pick a new monitor and resubmit
+ * any pending requests.
+ */
+static void mon_fault(struct ceph_connection *con)
+{
+	struct ceph_mon_client *monc = con->private;
+
+	mutex_lock(&monc->mutex);
+	dout("%s mon%d\n", __func__, monc->cur_mon);
+	if (monc->cur_mon >= 0) {
+		if (!monc->hunting) {
+			dout("%s hunting for new mon\n", __func__);
+			reopen_session(monc);
+			__schedule_delayed(monc);
+		} else {
+			dout("%s already hunting\n", __func__);
+		}
+	}
+	mutex_unlock(&monc->mutex);
+}
+
+/*
+ * We can ignore refcounting on the connection struct, as all references
+ * will come from the messenger workqueue, which is drained prior to
+ * mon_client destruction.
+ */
+static struct ceph_connection *mon_get_con(struct ceph_connection *con)
+{
+	return con;
+}
+
+static void mon_put_con(struct ceph_connection *con)
+{
+}
+
+static const struct ceph_connection_operations mon_con_ops = {
+	.get = mon_get_con,
+	.put = mon_put_con,
+	.alloc_msg = mon_alloc_msg,
+	.dispatch = mon_dispatch,
+	.fault = mon_fault,
+	.get_auth_request = mon_get_auth_request,
+	.handle_auth_reply_more = mon_handle_auth_reply_more,
+	.handle_auth_done = mon_handle_auth_done,
+	.handle_auth_bad_method = mon_handle_auth_bad_method,
+};