1 files changed, 565 insertions, 133 deletions

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 163fc74bf221..21c33ed048ed 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -20,6 +20,8 @@
 #include <linux/ceph/auth.h>
 #include <linux/ceph/debugfs.h>
 
+#define RECONNECT_MAX_SIZE (INT_MAX - PAGE_SIZE)
+
 /*
  * A cluster of MDS (metadata server) daemons is responsible for
  * managing the file system namespace (the directory hierarchy and
@@ -46,13 +48,17 @@
  */
 
 struct ceph_reconnect_state {
-	int nr_caps;
+	struct ceph_mds_session *session;
+	int nr_caps, nr_realms;
 	struct ceph_pagelist *pagelist;
 	unsigned msg_version;
+	bool allow_multi;
 };
 
 static void __wake_requests(struct ceph_mds_client *mdsc,
 			    struct list_head *head);
+static void ceph_cap_release_work(struct work_struct *work);
+static void ceph_cap_reclaim_work(struct work_struct *work);
 
 static const struct ceph_connection_operations mds_con_ops;
 
@@ -61,6 +67,29 @@ static const struct ceph_connection_operations mds_con_ops;
  * mds reply parsing
  */
 
+static int parse_reply_info_quota(void **p, void *end,
+				  struct ceph_mds_reply_info_in *info)
+{
+	u8 struct_v, struct_compat;
+	u32 struct_len;
+
+	ceph_decode_8_safe(p, end, struct_v, bad);
+	ceph_decode_8_safe(p, end, struct_compat, bad);
+	/* struct_v is expected to be >= 1. we only
+	 * understand encoding with struct_compat == 1. */
+	if (!struct_v || struct_compat != 1)
+		goto bad;
+	ceph_decode_32_safe(p, end, struct_len, bad);
+	ceph_decode_need(p, end, struct_len, bad);
+	end = *p + struct_len;
+	ceph_decode_64_safe(p, end, info->max_bytes, bad);
+	ceph_decode_64_safe(p, end, info->max_files, bad);
+	*p = end;
+	return 0;
+bad:
+	return -EIO;
+}
+
 /*
  * parse individual inode info
  */
@@ -68,8 +97,24 @@ static int parse_reply_info_in(void **p, void *end,
 			       struct ceph_mds_reply_info_in *info,
 			       u64 features)
 {
-	int err = -EIO;
+	int err = 0;
+	u8 struct_v = 0;
 
+	if (features == (u64)-1) {
+		u32 struct_len;
+		u8 struct_compat;
+		ceph_decode_8_safe(p, end, struct_v, bad);
+		ceph_decode_8_safe(p, end, struct_compat, bad);
+		/* struct_v is expected to be >= 1. we only understand
+		 * encoding with struct_compat == 1. */
+		if (!struct_v || struct_compat != 1)
+			goto bad;
+		ceph_decode_32_safe(p, end, struct_len, bad);
+		ceph_decode_need(p, end, struct_len, bad);
+		end = *p + struct_len;
+	}
+
+	ceph_decode_need(p, end, sizeof(struct ceph_mds_reply_inode), bad);
 	info->in = *p;
 	*p += sizeof(struct ceph_mds_reply_inode) +
 		sizeof(*info->in->fragtree.splits) *
@@ -87,49 +132,136 @@ static int parse_reply_info_in(void **p, void *end,
 	info->xattr_data = *p;
 	*p += info->xattr_len;
 
-	if (features & CEPH_FEATURE_MDS_INLINE_DATA) {
+	if (features == (u64)-1) {
+		/* inline data */
 		ceph_decode_64_safe(p, end, info->inline_version, bad);
 		ceph_decode_32_safe(p, end, info->inline_len, bad);
 		ceph_decode_need(p, end, info->inline_len, bad);
 		info->inline_data = *p;
 		*p += info->inline_len;
-	} else
-		info->inline_version = CEPH_INLINE_NONE;
+		/* quota */
+		err = parse_reply_info_quota(p, end, info);
+		if (err < 0)
+			goto out_bad;
+		/* pool namespace */
+		ceph_decode_32_safe(p, end, info->pool_ns_len, bad);
+		if (info->pool_ns_len > 0) {
+			ceph_decode_need(p, end, info->pool_ns_len, bad);
+			info->pool_ns_data = *p;
+			*p += info->pool_ns_len;
+		}
+		/* btime, change_attr */
+		{
+			struct ceph_timespec btime;
+			u64 change_attr;
+			ceph_decode_need(p, end, sizeof(btime), bad);
+			ceph_decode_copy(p, &btime, sizeof(btime));
+			ceph_decode_64_safe(p, end, change_attr, bad);
+		}
+
+		/* dir pin */
+		if (struct_v >= 2) {
+			ceph_decode_32_safe(p, end, info->dir_pin, bad);
+		} else {
+			info->dir_pin = -ENODATA;
+		}
+
+		*p = end;
+	} else {
+		if (features & CEPH_FEATURE_MDS_INLINE_DATA) {
+			ceph_decode_64_safe(p, end, info->inline_version, bad);
+			ceph_decode_32_safe(p, end, info->inline_len, bad);
+			ceph_decode_need(p, end, info->inline_len, bad);
+			info->inline_data = *p;
+			*p += info->inline_len;
+		} else
+			info->inline_version = CEPH_INLINE_NONE;
+
+		if (features & CEPH_FEATURE_MDS_QUOTA) {
+			err = parse_reply_info_quota(p, end, info);
+			if (err < 0)
+				goto out_bad;
+		} else {
+			info->max_bytes = 0;
+			info->max_files = 0;
+		}
+
+		info->pool_ns_len = 0;
+		info->pool_ns_data = NULL;
+		if (features & CEPH_FEATURE_FS_FILE_LAYOUT_V2) {
+			ceph_decode_32_safe(p, end, info->pool_ns_len, bad);
+			if (info->pool_ns_len > 0) {
+				ceph_decode_need(p, end, info->pool_ns_len, bad);
+				info->pool_ns_data = *p;
+				*p += info->pool_ns_len;
+			}
+		}
 
-	if (features & CEPH_FEATURE_MDS_QUOTA) {
+		info->dir_pin = -ENODATA;
+	}
+	return 0;
+bad:
+	err = -EIO;
+out_bad:
+	return err;
+}
+
+static int parse_reply_info_dir(void **p, void *end,
+				struct ceph_mds_reply_dirfrag **dirfrag,
+				u64 features)
+{
+	if (features == (u64)-1) {
 		u8 struct_v, struct_compat;
 		u32 struct_len;
-
-		/*
-		 * both struct_v and struct_compat are expected to be >= 1
-		 */
 		ceph_decode_8_safe(p, end, struct_v, bad);
 		ceph_decode_8_safe(p, end, struct_compat, bad);
-		if (!struct_v || !struct_compat)
+		/* struct_v is expected to be >= 1. we only understand
+		 * encoding whose struct_compat == 1. */
+		if (!struct_v || struct_compat != 1)
 			goto bad;
 		ceph_decode_32_safe(p, end, struct_len, bad);
 		ceph_decode_need(p, end, struct_len, bad);
-		ceph_decode_64_safe(p, end, info->max_bytes, bad);
-		ceph_decode_64_safe(p, end, info->max_files, bad);
-	} else {
-		info->max_bytes = 0;
-		info->max_files = 0;
+		end = *p + struct_len;
 	}
 
-	info->pool_ns_len = 0;
-	info->pool_ns_data = NULL;
-	if (features & CEPH_FEATURE_FS_FILE_LAYOUT_V2) {
-		ceph_decode_32_safe(p, end, info->pool_ns_len, bad);
-		if (info->pool_ns_len > 0) {
-			ceph_decode_need(p, end, info->pool_ns_len, bad);
-			info->pool_ns_data = *p;
-			*p += info->pool_ns_len;
-		}
+	ceph_decode_need(p, end, sizeof(**dirfrag), bad);
+	*dirfrag = *p;
+	*p += sizeof(**dirfrag) + sizeof(u32) * le32_to_cpu((*dirfrag)->ndist);
+	if (unlikely(*p > end))
+		goto bad;
+	if (features == (u64)-1)
+		*p = end;
+	return 0;
+bad:
+	return -EIO;
+}
+
+static int parse_reply_info_lease(void **p, void *end,
+				  struct ceph_mds_reply_lease **lease,
+				  u64 features)
+{
+	if (features == (u64)-1) {
+		u8 struct_v, struct_compat;
+		u32 struct_len;
+		ceph_decode_8_safe(p, end, struct_v, bad);
+		ceph_decode_8_safe(p, end, struct_compat, bad);
+		/* struct_v is expected to be >= 1. we only understand
+		 * encoding whose struct_compat == 1. */
+		if (!struct_v || struct_compat != 1)
+			goto bad;
+		ceph_decode_32_safe(p, end, struct_len, bad);
+		ceph_decode_need(p, end, struct_len, bad);
+		end = *p + struct_len;
 	}
 
+	ceph_decode_need(p, end, sizeof(**lease), bad);
+	*lease = *p;
+	*p += sizeof(**lease);
+	if (features == (u64)-1)
+		*p = end;
 	return 0;
 bad:
-	return err;
+	return -EIO;
 }
 
 /*
@@ -147,20 +279,18 @@ static int parse_reply_info_trace(void **p, void *end,
 		if (err < 0)
 			goto out_bad;
 
-		if (unlikely(*p + sizeof(*info->dirfrag) > end))
-			goto bad;
-		info->dirfrag = *p;
-		*p += sizeof(*info->dirfrag) +
-			sizeof(u32)*le32_to_cpu(info->dirfrag->ndist);
-		if (unlikely(*p > end))
-			goto bad;
+		err = parse_reply_info_dir(p, end, &info->dirfrag, features);
+		if (err < 0)
+			goto out_bad;
 
 		ceph_decode_32_safe(p, end, info->dname_len, bad);
 		ceph_decode_need(p, end, info->dname_len, bad);
 		info->dname = *p;
 		*p += info->dname_len;
-		info->dlease = *p;
-		*p += sizeof(*info->dlease);
+
+		err = parse_reply_info_lease(p, end, &info->dlease, features);
+		if (err < 0)
+			goto out_bad;
 	}
 
 	if (info->head->is_target) {
@@ -183,20 +313,16 @@ out_bad:
 /*
  * parse readdir results
  */
-static int parse_reply_info_dir(void **p, void *end,
+static int parse_reply_info_readdir(void **p, void *end,
 				struct ceph_mds_reply_info_parsed *info,
 				u64 features)
 {
 	u32 num, i = 0;
 	int err;
 
-	info->dir_dir = *p;
-	if (*p + sizeof(*info->dir_dir) > end)
-		goto bad;
-	*p += sizeof(*info->dir_dir) +
-		sizeof(u32)*le32_to_cpu(info->dir_dir->ndist);
-	if (*p > end)
-		goto bad;
+	err = parse_reply_info_dir(p, end, &info->dir_dir, features);
+	if (err < 0)
+		goto out_bad;
 
 	ceph_decode_need(p, end, sizeof(num) + 2, bad);
 	num = ceph_decode_32(p);
@@ -222,15 +348,16 @@ static int parse_reply_info_dir(void **p, void *end,
 	while (num) {
 		struct ceph_mds_reply_dir_entry *rde = info->dir_entries + i;
 		/* dentry */
-		ceph_decode_need(p, end, sizeof(u32)*2, bad);
-		rde->name_len = ceph_decode_32(p);
+		ceph_decode_32_safe(p, end, rde->name_len, bad);
 		ceph_decode_need(p, end, rde->name_len, bad);
 		rde->name = *p;
 		*p += rde->name_len;
 		dout("parsed dir dname '%.*s'\n", rde->name_len, rde->name);
-		rde->lease = *p;
-		*p += sizeof(struct ceph_mds_reply_lease);
 
+		/* dentry lease */
+		err = parse_reply_info_lease(p, end, &rde->lease, features);
+		if (err)
+			goto out_bad;
 		/* inode */
 		err = parse_reply_info_in(p, end, &rde->inode, features);
 		if (err < 0)
@@ -281,7 +408,8 @@ static int parse_reply_info_create(void **p, void *end,
 				  struct ceph_mds_reply_info_parsed *info,
 				  u64 features)
 {
-	if (features & CEPH_FEATURE_REPLY_CREATE_INODE) {
+	if (features == (u64)-1 ||
+	    (features & CEPH_FEATURE_REPLY_CREATE_INODE)) {
 		if (*p == end) {
 			info->has_create_ino = false;
 		} else {
@@ -310,7 +438,7 @@ static int parse_reply_info_extra(void **p, void *end,
 	if (op == CEPH_MDS_OP_GETFILELOCK)
 		return parse_reply_info_filelock(p, end, info, features);
 	else if (op == CEPH_MDS_OP_READDIR || op == CEPH_MDS_OP_LSSNAP)
-		return parse_reply_info_dir(p, end, info, features);
+		return parse_reply_info_readdir(p, end, info, features);
 	else if (op == CEPH_MDS_OP_CREATE)
 		return parse_reply_info_create(p, end, info, features);
 	else
@@ -494,7 +622,7 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
 	ceph_con_init(&s->s_con, s, &mds_con_ops, &mdsc->fsc->client->msgr);
 
 	spin_lock_init(&s->s_gen_ttl_lock);
-	s->s_cap_gen = 0;
+	s->s_cap_gen = 1;
 	s->s_cap_ttl = jiffies - 1;
 
 	spin_lock_init(&s->s_cap_lock);
@@ -510,6 +638,8 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
 	s->s_cap_reconnect = 0;
 	s->s_cap_iterator = NULL;
 	INIT_LIST_HEAD(&s->s_cap_releases);
+	INIT_WORK(&s->s_cap_release_work, ceph_cap_release_work);
+
 	INIT_LIST_HEAD(&s->s_cap_flushing);
 
 	mdsc->sessions[mds] = s;
@@ -535,6 +665,7 @@ static void __unregister_session(struct ceph_mds_client *mdsc,
 	dout("__unregister_session mds%d %p\n", s->s_mds, s);
 	BUG_ON(mdsc->sessions[s->s_mds] != s);
 	mdsc->sessions[s->s_mds] = NULL;
+	s->s_state = 0;
 	ceph_con_close(&s->s_con);
 	ceph_put_mds_session(s);
 	atomic_dec(&mdsc->num_sessions);
@@ -1197,13 +1328,10 @@ static int iterate_session_caps(struct ceph_mds_session *session,
 			cap->session = NULL;
 			list_del_init(&cap->session_caps);
 			session->s_nr_caps--;
-			if (cap->queue_release) {
-				list_add_tail(&cap->session_caps,
-					      &session->s_cap_releases);
-				session->s_num_cap_releases++;
-			} else {
+			if (cap->queue_release)
+				__ceph_queue_cap_release(session, cap);
+			else
 				old_cap = cap;  /* put_cap it w/o locks held */
-			}
 		}
 		if (ret < 0)
 			goto out;
@@ -1638,7 +1766,7 @@ int ceph_trim_caps(struct ceph_mds_client *mdsc,
 		session->s_trim_caps = 0;
 	}
 
-	ceph_send_cap_releases(mdsc, session);
+	ceph_flush_cap_releases(mdsc, session);
 	return 0;
 }
 
@@ -1681,8 +1809,8 @@ static void wait_caps_flush(struct ceph_mds_client *mdsc,
 /*
  * called under s_mutex
  */
-void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
-			    struct ceph_mds_session *session)
+static void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
+				   struct ceph_mds_session *session)
 {
 	struct ceph_msg *msg = NULL;
 	struct ceph_mds_cap_release *head;
@@ -1774,6 +1902,81 @@ out_err:
 	spin_unlock(&session->s_cap_lock);
 }
 
+static void ceph_cap_release_work(struct work_struct *work)
+{
+	struct ceph_mds_session *session =
+		container_of(work, struct ceph_mds_session, s_cap_release_work);
+
+	mutex_lock(&session->s_mutex);
+	if (session->s_state == CEPH_MDS_SESSION_OPEN ||
+	    session->s_state == CEPH_MDS_SESSION_HUNG)
+		ceph_send_cap_releases(session->s_mdsc, session);
+	mutex_unlock(&session->s_mutex);
+	ceph_put_mds_session(session);
+}
+
+void ceph_flush_cap_releases(struct ceph_mds_client *mdsc,
+		             struct ceph_mds_session *session)
+{
+	if (mdsc->stopping)
+		return;
+
+	get_session(session);
+	if (queue_work(mdsc->fsc->cap_wq,
+		       &session->s_cap_release_work)) {
+		dout("cap release work queued\n");
+	} else {
+		ceph_put_mds_session(session);
+		dout("failed to queue cap release work\n");
+	}
+}
+
+/*
+ * caller holds session->s_cap_lock
+ */
+void __ceph_queue_cap_release(struct ceph_mds_session *session,
+			      struct ceph_cap *cap)
+{
+	list_add_tail(&cap->session_caps, &session->s_cap_releases);
+	session->s_num_cap_releases++;
+
+	if (!(session->s_num_cap_releases % CEPH_CAPS_PER_RELEASE))
+		ceph_flush_cap_releases(session->s_mdsc, session);
+}
+
+static void ceph_cap_reclaim_work(struct work_struct *work)
+{
+	struct ceph_mds_client *mdsc =
+		container_of(work, struct ceph_mds_client, cap_reclaim_work);
+	int ret = ceph_trim_dentries(mdsc);
+	if (ret == -EAGAIN)
+		ceph_queue_cap_reclaim_work(mdsc);
+}
+
+void ceph_queue_cap_reclaim_work(struct ceph_mds_client *mdsc)
+{
+	if (mdsc->stopping)
+		return;
+
+        if (queue_work(mdsc->fsc->cap_wq, &mdsc->cap_reclaim_work)) {
+                dout("caps reclaim work queued\n");
+        } else {
+                dout("failed to queue caps release work\n");
+        }
+}
+
+void ceph_reclaim_caps_nr(struct ceph_mds_client *mdsc, int nr)
+{
+	int val;
+	if (!nr)
+		return;
+	val = atomic_add_return(nr, &mdsc->cap_reclaim_pending);
+	if (!(val % CEPH_CAPS_PER_RELEASE)) {
+		atomic_set(&mdsc->cap_reclaim_pending, 0);
+		ceph_queue_cap_reclaim_work(mdsc);
+	}
+}
+
 /*
  * requests
  */
@@ -2653,7 +2856,10 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 
 	dout("handle_reply tid %lld result %d\n", tid, result);
 	rinfo = &req->r_reply_info;
-	err = parse_reply_info(msg, rinfo, session->s_con.peer_features);
+	if (test_bit(CEPHFS_FEATURE_REPLY_ENCODING, &session->s_features))
+		err = parse_reply_info(msg, rinfo, (u64)-1);
+	else
+		err = parse_reply_info(msg, rinfo, session->s_con.peer_features);
 	mutex_unlock(&mdsc->mutex);
 
 	mutex_lock(&session->s_mutex);
@@ -2684,7 +2890,6 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 		if (result == 0 && (req->r_op == CEPH_MDS_OP_READDIR ||
 				    req->r_op == CEPH_MDS_OP_LSSNAP))
 			ceph_readdir_prepopulate(req, req->r_session);
-		ceph_unreserve_caps(mdsc, &req->r_caps_reservation);
 	}
 	current->journal_info = NULL;
 	mutex_unlock(&req->r_fill_mutex);
@@ -2693,12 +2898,18 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 	if (realm)
 		ceph_put_snap_realm(mdsc, realm);
 
-	if (err == 0 && req->r_target_inode &&
-	    test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
-		struct ceph_inode_info *ci = ceph_inode(req->r_target_inode);
-		spin_lock(&ci->i_unsafe_lock);
-		list_add_tail(&req->r_unsafe_target_item, &ci->i_unsafe_iops);
-		spin_unlock(&ci->i_unsafe_lock);
+	if (err == 0) {
+		if (req->r_target_inode &&
+		    test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
+			struct ceph_inode_info *ci =
+				ceph_inode(req->r_target_inode);
+			spin_lock(&ci->i_unsafe_lock);
+			list_add_tail(&req->r_unsafe_target_item,
+				      &ci->i_unsafe_iops);
+			spin_unlock(&ci->i_unsafe_lock);
+		}
+
+		ceph_unreserve_caps(mdsc, &req->r_caps_reservation);
 	}
 out_err:
 	mutex_lock(&mdsc->mutex);
@@ -2777,6 +2988,25 @@ bad:
 	pr_err("mdsc_handle_forward decode error err=%d\n", err);
 }
 
+static int __decode_and_drop_session_metadata(void **p, void *end)
+{
+	/* map<string,string> */
+	u32 n;
+	ceph_decode_32_safe(p, end, n, bad);
+	while (n-- > 0) {
+		u32 len;
+		ceph_decode_32_safe(p, end, len, bad);
+		ceph_decode_need(p, end, len, bad);
+		*p += len;
+		ceph_decode_32_safe(p, end, len, bad);
+		ceph_decode_need(p, end, len, bad);
+		*p += len;
+	}
+	return 0;
+bad:
+	return -1;
+}
+
 /*
  * handle a mds session control message
  */
@@ -2784,18 +3014,36 @@ static void handle_session(struct ceph_mds_session *session,
 			   struct ceph_msg *msg)
 {
 	struct ceph_mds_client *mdsc = session->s_mdsc;
+	int mds = session->s_mds;
+	int msg_version = le16_to_cpu(msg->hdr.version);
+	void *p = msg->front.iov_base;
+	void *end = p + msg->front.iov_len;
+	struct ceph_mds_session_head *h;
 	u32 op;
 	u64 seq;
-	int mds = session->s_mds;
-	struct ceph_mds_session_head *h = msg->front.iov_base;
+	unsigned long features = 0;
 	int wake = 0;
 
 	/* decode */
-	if (msg->front.iov_len < sizeof(*h))
-		goto bad;
+	ceph_decode_need(&p, end, sizeof(*h), bad);
+	h = p;
+	p += sizeof(*h);
+
 	op = le32_to_cpu(h->op);
 	seq = le64_to_cpu(h->seq);
 
+	if (msg_version >= 3) {
+		u32 len;
+		/* version >= 2, metadata */
+		if (__decode_and_drop_session_metadata(&p, end) < 0)
+			goto bad;
+		/* version >= 3, feature bits */
+		ceph_decode_32_safe(&p, end, len, bad);
+		ceph_decode_need(&p, end, len, bad);
+		memcpy(&features, p, min_t(size_t, len, sizeof(features)));
+		p += len;
+	}
+
 	mutex_lock(&mdsc->mutex);
 	if (op == CEPH_SESSION_CLOSE) {
 		get_session(session);
@@ -2821,6 +3069,7 @@ static void handle_session(struct ceph_mds_session *session,
 		if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
 			pr_info("mds%d reconnect success\n", session->s_mds);
 		session->s_state = CEPH_MDS_SESSION_OPEN;
+		session->s_features = features;
 		renewed_caps(mdsc, session, 0);
 		wake = 1;
 		if (mdsc->stopping)
@@ -2947,6 +3196,82 @@ static void replay_unsafe_requests(struct ceph_mds_client *mdsc,
 	mutex_unlock(&mdsc->mutex);
 }
 
+static int send_reconnect_partial(struct ceph_reconnect_state *recon_state)
+{
+	struct ceph_msg *reply;
+	struct ceph_pagelist *_pagelist;
+	struct page *page;
+	__le32 *addr;
+	int err = -ENOMEM;
+
+	if (!recon_state->allow_multi)
+		return -ENOSPC;
+
+	/* can't handle message that contains both caps and realm */
+	BUG_ON(!recon_state->nr_caps == !recon_state->nr_realms);
+
+	/* pre-allocate new pagelist */
+	_pagelist = ceph_pagelist_alloc(GFP_NOFS);
+	if (!_pagelist)
+		return -ENOMEM;
+
+	reply = ceph_msg_new2(CEPH_MSG_CLIENT_RECONNECT, 0, 1, GFP_NOFS, false);
+	if (!reply)
+		goto fail_msg;
+
+	/* placeholder for nr_caps */
+	err = ceph_pagelist_encode_32(_pagelist, 0);
+	if (err < 0)
+		goto fail;
+
+	if (recon_state->nr_caps) {
+		/* currently encoding caps */
+		err = ceph_pagelist_encode_32(recon_state->pagelist, 0);
+		if (err)
+			goto fail;
+	} else {
+		/* placeholder for nr_realms (currently encoding relams) */
+		err = ceph_pagelist_encode_32(_pagelist, 0);
+		if (err < 0)
+			goto fail;
+	}
+
+	err = ceph_pagelist_encode_8(recon_state->pagelist, 1);
+	if (err)
+		goto fail;
+
+	page = list_first_entry(&recon_state->pagelist->head, struct page, lru);
+	addr = kmap_atomic(page);
+	if (recon_state->nr_caps) {
+		/* currently encoding caps */
+		*addr = cpu_to_le32(recon_state->nr_caps);
+	} else {
+		/* currently encoding relams */
+		*(addr + 1) = cpu_to_le32(recon_state->nr_realms);
+	}
+	kunmap_atomic(addr);
+
+	reply->hdr.version = cpu_to_le16(5);
+	reply->hdr.compat_version = cpu_to_le16(4);
+
+	reply->hdr.data_len = cpu_to_le32(recon_state->pagelist->length);
+	ceph_msg_data_add_pagelist(reply, recon_state->pagelist);
+
+	ceph_con_send(&recon_state->session->s_con, reply);
+	ceph_pagelist_release(recon_state->pagelist);
+
+	recon_state->pagelist = _pagelist;
+	recon_state->nr_caps = 0;
+	recon_state->nr_realms = 0;
+	recon_state->msg_version = 5;
+	return 0;
+fail:
+	ceph_msg_put(reply);
+fail_msg:
+	ceph_pagelist_release(_pagelist);
+	return err;
+}
+
 /*
  * Encode information about a cap for a reconnect with the MDS.
  */
@@ -2966,9 +3291,6 @@ static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
 	dout(" adding %p ino %llx.%llx cap %p %lld %s\n",
 	     inode, ceph_vinop(inode), cap, cap->cap_id,
 	     ceph_cap_string(cap->issued));
-	err = ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
-	if (err)
-		return err;
 
 	spin_lock(&ci->i_ceph_lock);
 	cap->seq = 0;        /* reset cap seq */
@@ -3008,7 +3330,7 @@ static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
 	if (recon_state->msg_version >= 2) {
 		int num_fcntl_locks, num_flock_locks;
 		struct ceph_filelock *flocks = NULL;
-		size_t struct_len, total_len = 0;
+		size_t struct_len, total_len = sizeof(u64);
 		u8 struct_v = 0;
 
 encode_again:
@@ -3043,7 +3365,7 @@ encode_again:
 
 		if (recon_state->msg_version >= 3) {
 			/* version, compat_version and struct_len */
-			total_len = 2 * sizeof(u8) + sizeof(u32);
+			total_len += 2 * sizeof(u8) + sizeof(u32);
 			struct_v = 2;
 		}
 		/*
@@ -3060,12 +3382,19 @@ encode_again:
 			struct_len += sizeof(u64); /* snap_follows */
 
 		total_len += struct_len;
-		err = ceph_pagelist_reserve(pagelist, total_len);
-		if (err) {
-			kfree(flocks);
-			goto out_err;
+
+		if (pagelist->length + total_len > RECONNECT_MAX_SIZE) {
+			err = send_reconnect_partial(recon_state);
+			if (err)
+				goto out_freeflocks;
+			pagelist = recon_state->pagelist;
 		}
 
+		err = ceph_pagelist_reserve(pagelist, total_len);
+		if (err)
+			goto out_freeflocks;
+
+		ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
 		if (recon_state->msg_version >= 3) {
 			ceph_pagelist_encode_8(pagelist, struct_v);
 			ceph_pagelist_encode_8(pagelist, 1);
@@ -3077,7 +3406,7 @@ encode_again:
 				       num_fcntl_locks, num_flock_locks);
 		if (struct_v >= 2)
 			ceph_pagelist_encode_64(pagelist, snap_follows);
-
+out_freeflocks:
 		kfree(flocks);
 	} else {
 		u64 pathbase = 0;
@@ -3098,20 +3427,81 @@ encode_again:
 		}
 
 		err = ceph_pagelist_reserve(pagelist,
-				pathlen + sizeof(u32) + sizeof(rec.v1));
+					    sizeof(u64) + sizeof(u32) +
+					    pathlen + sizeof(rec.v1));
 		if (err) {
-			kfree(path);
-			goto out_err;
+			goto out_freepath;
 		}
 
+		ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
 		ceph_pagelist_encode_string(pagelist, path, pathlen);
 		ceph_pagelist_append(pagelist, &rec, sizeof(rec.v1));
-
+out_freepath:
 		kfree(path);
 	}
 
-	recon_state->nr_caps++;
 out_err:
+	if (err >= 0)
+		recon_state->nr_caps++;
+	return err;
+}
+
+static int encode_snap_realms(struct ceph_mds_client *mdsc,
+			      struct ceph_reconnect_state *recon_state)
+{
+	struct rb_node *p;
+	struct ceph_pagelist *pagelist = recon_state->pagelist;
+	int err = 0;
+
+	if (recon_state->msg_version >= 4) {
+		err = ceph_pagelist_encode_32(pagelist, mdsc->num_snap_realms);
+		if (err < 0)
+			goto fail;
+	}
+
+	/*
+	 * snaprealms.  we provide mds with the ino, seq (version), and
+	 * parent for all of our realms.  If the mds has any newer info,
+	 * it will tell us.
+	 */
+	for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
+		struct ceph_snap_realm *realm =
+		       rb_entry(p, struct ceph_snap_realm, node);
+		struct ceph_mds_snaprealm_reconnect sr_rec;
+
+		if (recon_state->msg_version >= 4) {
+			size_t need = sizeof(u8) * 2 + sizeof(u32) +
+				      sizeof(sr_rec);
+
+			if (pagelist->length + need > RECONNECT_MAX_SIZE) {
+				err = send_reconnect_partial(recon_state);
+				if (err)
+					goto fail;
+				pagelist = recon_state->pagelist;
+			}
+
+			err = ceph_pagelist_reserve(pagelist, need);
+			if (err)
+				goto fail;
+
+			ceph_pagelist_encode_8(pagelist, 1);
+			ceph_pagelist_encode_8(pagelist, 1);
+			ceph_pagelist_encode_32(pagelist, sizeof(sr_rec));
+		}
+
+		dout(" adding snap realm %llx seq %lld parent %llx\n",
+		     realm->ino, realm->seq, realm->parent_ino);
+		sr_rec.ino = cpu_to_le64(realm->ino);
+		sr_rec.seq = cpu_to_le64(realm->seq);
+		sr_rec.parent = cpu_to_le64(realm->parent_ino);
+
+		err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
+		if (err)
+			goto fail;
+
+		recon_state->nr_realms++;
+	}
+fail:
 	return err;
 }
 
@@ -3132,18 +3522,17 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc,
 			       struct ceph_mds_session *session)
 {
 	struct ceph_msg *reply;
-	struct rb_node *p;
 	int mds = session->s_mds;
 	int err = -ENOMEM;
-	int s_nr_caps;
-	struct ceph_pagelist *pagelist;
-	struct ceph_reconnect_state recon_state;
+	struct ceph_reconnect_state recon_state = {
+		.session = session,
+	};
 	LIST_HEAD(dispose);
 
 	pr_info("mds%d reconnect start\n", mds);
 
-	pagelist = ceph_pagelist_alloc(GFP_NOFS);
-	if (!pagelist)
+	recon_state.pagelist = ceph_pagelist_alloc(GFP_NOFS);
+	if (!recon_state.pagelist)
 		goto fail_nopagelist;
 
 	reply = ceph_msg_new2(CEPH_MSG_CLIENT_RECONNECT, 0, 1, GFP_NOFS, false);
@@ -3187,63 +3576,90 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc,
 	/* replay unsafe requests */
 	replay_unsafe_requests(mdsc, session);
 
+	ceph_early_kick_flushing_caps(mdsc, session);
+
 	down_read(&mdsc->snap_rwsem);
 
-	/* traverse this session's caps */
-	s_nr_caps = session->s_nr_caps;
-	err = ceph_pagelist_encode_32(pagelist, s_nr_caps);
+	/* placeholder for nr_caps */
+	err = ceph_pagelist_encode_32(recon_state.pagelist, 0);
 	if (err)
 		goto fail;
 
-	recon_state.nr_caps = 0;
-	recon_state.pagelist = pagelist;
-	if (session->s_con.peer_features & CEPH_FEATURE_MDSENC)
+	if (test_bit(CEPHFS_FEATURE_MULTI_RECONNECT, &session->s_features)) {
 		recon_state.msg_version = 3;
-	else
+		recon_state.allow_multi = true;
+	} else if (session->s_con.peer_features & CEPH_FEATURE_MDSENC) {
+		recon_state.msg_version = 3;
+	} else {
 		recon_state.msg_version = 2;
+	}
+	/* trsaverse this session's caps */
 	err = iterate_session_caps(session, encode_caps_cb, &recon_state);
-	if (err < 0)
-		goto fail;
 
 	spin_lock(&session->s_cap_lock);
 	session->s_cap_reconnect = 0;
 	spin_unlock(&session->s_cap_lock);
 
-	/*
-	 * snaprealms.  we provide mds with the ino, seq (version), and
-	 * parent for all of our realms.  If the mds has any newer info,
-	 * it will tell us.
-	 */
-	for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
-		struct ceph_snap_realm *realm =
-			rb_entry(p, struct ceph_snap_realm, node);
-		struct ceph_mds_snaprealm_reconnect sr_rec;
+	if (err < 0)
+		goto fail;
 
-		dout(" adding snap realm %llx seq %lld parent %llx\n",
-		     realm->ino, realm->seq, realm->parent_ino);
-		sr_rec.ino = cpu_to_le64(realm->ino);
-		sr_rec.seq = cpu_to_le64(realm->seq);
-		sr_rec.parent = cpu_to_le64(realm->parent_ino);
-		err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
-		if (err)
-			goto fail;
+	/* check if all realms can be encoded into current message */
+	if (mdsc->num_snap_realms) {
+		size_t total_len =
+			recon_state.pagelist->length +
+			mdsc->num_snap_realms *
+			sizeof(struct ceph_mds_snaprealm_reconnect);
+		if (recon_state.msg_version >= 4) {
+			/* number of realms */
+			total_len += sizeof(u32);
+			/* version, compat_version and struct_len */
+			total_len += mdsc->num_snap_realms *
+				     (2 * sizeof(u8) + sizeof(u32));
+		}
+		if (total_len > RECONNECT_MAX_SIZE) {
+			if (!recon_state.allow_multi) {
+				err = -ENOSPC;
+				goto fail;
+			}
+			if (recon_state.nr_caps) {
+				err = send_reconnect_partial(&recon_state);
+				if (err)
+					goto fail;
+			}
+			recon_state.msg_version = 5;
+		}
 	}
 
-	reply->hdr.version = cpu_to_le16(recon_state.msg_version);
+	err = encode_snap_realms(mdsc, &recon_state);
+	if (err < 0)
+		goto fail;
 
-	/* raced with cap release? */
-	if (s_nr_caps != recon_state.nr_caps) {
-		struct page *page = list_first_entry(&pagelist->head,
-						     struct page, lru);
+	if (recon_state.msg_version >= 5) {
+		err = ceph_pagelist_encode_8(recon_state.pagelist, 0);
+		if (err < 0)
+			goto fail;
+	}
+
+	if (recon_state.nr_caps || recon_state.nr_realms) {
+		struct page *page =
+			list_first_entry(&recon_state.pagelist->head,
+					struct page, lru);
 		__le32 *addr = kmap_atomic(page);
-		*addr = cpu_to_le32(recon_state.nr_caps);
+		if (recon_state.nr_caps) {
+			WARN_ON(recon_state.nr_realms != mdsc->num_snap_realms);
+			*addr = cpu_to_le32(recon_state.nr_caps);
+		} else if (recon_state.msg_version >= 4) {
+			*(addr + 1) = cpu_to_le32(recon_state.nr_realms);
+		}
 		kunmap_atomic(addr);
 	}
 
-	reply->hdr.data_len = cpu_to_le32(pagelist->length);
-	ceph_msg_data_add_pagelist(reply, pagelist);
+	reply->hdr.version = cpu_to_le16(recon_state.msg_version);
+	if (recon_state.msg_version >= 4)
+		reply->hdr.compat_version = cpu_to_le16(4);
 
-	ceph_early_kick_flushing_caps(mdsc, session);
+	reply->hdr.data_len = cpu_to_le32(recon_state.pagelist->length);
+	ceph_msg_data_add_pagelist(reply, recon_state.pagelist);
 
 	ceph_con_send(&session->s_con, reply);
 
@@ -3254,7 +3670,7 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc,
 	mutex_unlock(&mdsc->mutex);
 
 	up_read(&mdsc->snap_rwsem);
-	ceph_pagelist_release(pagelist);
+	ceph_pagelist_release(recon_state.pagelist);
 	return;
 
 fail:
@@ -3262,7 +3678,7 @@ fail:
 	up_read(&mdsc->snap_rwsem);
 	mutex_unlock(&session->s_mutex);
 fail_nomsg:
-	ceph_pagelist_release(pagelist);
+	ceph_pagelist_release(recon_state.pagelist);
 fail_nopagelist:
 	pr_err("error %d preparing reconnect for mds%d\n", err, mds);
 	return;
@@ -3580,7 +3996,6 @@ static void delayed_work(struct work_struct *work)
 	int renew_caps;
 
 	dout("mdsc delayed_work\n");
-	ceph_check_delayed_caps(mdsc);
 
 	mutex_lock(&mdsc->mutex);
 	renew_interval = mdsc->mdsmap->m_session_timeout >> 2;
@@ -3628,6 +4043,12 @@ static void delayed_work(struct work_struct *work)
 	}
 	mutex_unlock(&mdsc->mutex);
 
+	ceph_check_delayed_caps(mdsc);
+
+	ceph_queue_cap_reclaim_work(mdsc);
+
+	ceph_trim_snapid_map(mdsc);
+
 	schedule_delayed(mdsc);
 }
 
@@ -3660,6 +4081,7 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
 	init_rwsem(&mdsc->snap_rwsem);
 	mdsc->snap_realms = RB_ROOT;
 	INIT_LIST_HEAD(&mdsc->snap_empty);
+	mdsc->num_snap_realms = 0;
 	spin_lock_init(&mdsc->snap_empty_lock);
 	mdsc->last_tid = 0;
 	mdsc->oldest_tid = 0;
@@ -3677,11 +4099,19 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
 	mdsc->num_cap_flushing = 0;
 	spin_lock_init(&mdsc->cap_dirty_lock);
 	init_waitqueue_head(&mdsc->cap_flushing_wq);
-	spin_lock_init(&mdsc->dentry_lru_lock);
-	INIT_LIST_HEAD(&mdsc->dentry_lru);
+	INIT_WORK(&mdsc->cap_reclaim_work, ceph_cap_reclaim_work);
+	atomic_set(&mdsc->cap_reclaim_pending, 0);
+
+	spin_lock_init(&mdsc->dentry_list_lock);
+	INIT_LIST_HEAD(&mdsc->dentry_leases);
+	INIT_LIST_HEAD(&mdsc->dentry_dir_leases);
 
 	ceph_caps_init(mdsc);
-	ceph_adjust_min_caps(mdsc, fsc->min_caps);
+	ceph_adjust_caps_max_min(mdsc, fsc->mount_options);
+
+	spin_lock_init(&mdsc->snapid_map_lock);
+	mdsc->snapid_map_tree = RB_ROOT;
+	INIT_LIST_HEAD(&mdsc->snapid_map_lru);
 
 	init_rwsem(&mdsc->pool_perm_rwsem);
 	mdsc->pool_perm_tree = RB_ROOT;
@@ -3876,8 +4306,10 @@ void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
 	WARN_ON(!list_empty(&mdsc->cap_delay_list));
 	mutex_unlock(&mdsc->mutex);
 
+	ceph_cleanup_snapid_map(mdsc);
 	ceph_cleanup_empty_realms(mdsc);
 
+	cancel_work_sync(&mdsc->cap_reclaim_work);
 	cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
 
 	dout("stopped\n");