Merge remote branch 'ceph/for-next'

18 files changed, 2624 insertions, 153 deletions

diff --git a/fs/ceph/Kconfig b/fs/ceph/Kconfig
index 04b8280582a9..4c49d18303db 100644
--- a/fs/ceph/Kconfig
+++ b/fs/ceph/Kconfig
@@ -25,3 +25,13 @@ config CEPH_FS_PRETTYDEBUG
 
 	  If unsure, say N.
 
+config CEPH_RBD
+	bool "Rados block device (RBD)"
+	depends on CEPH_FS
+	select  CONFIG_BLOCK
+	default y
+	help
+	  If you say Y here, ceph will include rbd, the RADOS block
+	  device which stripes a block device over objects stored in
+	  the Ceph distributed object store.
+
diff --git a/fs/ceph/Makefile b/fs/ceph/Makefile
index 6a660e610be8..d2f6326c01dc 100644
--- a/fs/ceph/Makefile
+++ b/fs/ceph/Makefile
@@ -18,6 +18,8 @@ ceph-objs := super.o inode.o dir.o file.o addr.o ioctl.o \
 	auth_x.o \
 	ceph_fs.o ceph_strings.o ceph_hash.o ceph_frag.o
 
+obj-$(CONFIG_RBD) += rbd.o
+
 else
 #Otherwise we were called directly from the command
 # line; invoke the kernel build system.
diff --git a/fs/ceph/README b/fs/ceph/README
index 18352fab37c0..e2046ec8e54a 100644
--- a/fs/ceph/README
+++ b/fs/ceph/README
@@ -7,6 +7,7 @@ src/include/ceph_fs.h	    fs/ceph/ceph_fs.h
 src/include/ceph_fs.cc	    fs/ceph/ceph_fs.c
 src/include/msgr.h	    fs/ceph/msgr.h
 src/include/rados.h	    fs/ceph/rados.h
+src/include/rbd_types.h	    fs/ceph/rbd_types.h
 src/include/ceph_strings.cc fs/ceph/ceph_strings.c
 src/include/ceph_frag.h	    fs/ceph/ceph_frag.h
 src/include/ceph_frag.cc    fs/ceph/ceph_frag.c
diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index 3be33fb066cc..c5d6a01d1214 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -440,9 +440,14 @@ int ceph_debugfs_client_init(struct ceph_client *client)
 	if (!client->debugfs_congestion_kb)
 		goto out;
 
-	sprintf(name, "../../bdi/%s", dev_name(client->sb->s_bdi->dev));
-	client->debugfs_bdi = debugfs_create_symlink("bdi", client->debugfs_dir,
-						     name);
+	if (client->backing_dev_info.dev) {
+		sprintf(name, "../../bdi/%s",
+			dev_name(client->backing_dev_info.dev));
+		client->debugfs_bdi =
+			debugfs_create_symlink("bdi",
+					       client->debugfs_dir,
+					       name);
+	}
 
 	return 0;
 
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 6251a1574b94..4c21b51c833a 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -363,6 +363,52 @@ static int copy_user_to_page_vector(struct page **pages,
 	return len;
 }
 
+int ceph_copy_to_page_vector(struct page **pages,
+				    const char *data,
+				    loff_t off, size_t len)
+{
+	int i = 0;
+	size_t po = off & ~PAGE_CACHE_MASK;
+	size_t left = len;
+	size_t l;
+
+	while (left > 0) {
+		l = min_t(size_t, PAGE_CACHE_SIZE-po, left);
+		memcpy(page_address(pages[i]) + po, data, l);
+		data += l;
+		left -= l;
+		po += l;
+		if (po == PAGE_CACHE_SIZE) {
+			po = 0;
+			i++;
+		}
+	}
+	return len;
+}
+
+int ceph_copy_from_page_vector(struct page **pages,
+				    char *data,
+				    loff_t off, size_t len)
+{
+	int i = 0;
+	size_t po = off & ~PAGE_CACHE_MASK;
+	size_t left = len;
+	size_t l;
+
+	while (left > 0) {
+		l = min_t(size_t, PAGE_CACHE_SIZE-po, left);
+		memcpy(data, page_address(pages[i]) + po, l);
+		data += l;
+		left -= l;
+		po += l;
+		if (po == PAGE_CACHE_SIZE) {
+			po = 0;
+			i++;
+		}
+	}
+	return len;
+}
+
 /*
  * copy user data from a page vector into a user pointer
  */
diff --git a/fs/ceph/messenger.c b/fs/ceph/messenger.c
index 64b8b1f7863d..8785ca41becd 100644
--- a/fs/ceph/messenger.c
+++ b/fs/ceph/messenger.c
@@ -9,6 +9,8 @@
 #include <linux/slab.h>
 #include <linux/socket.h>
 #include <linux/string.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
 #include <net/tcp.h>
 
 #include "super.h"
@@ -539,8 +541,11 @@ static void prepare_write_message(struct ceph_connection *con)
 	if (le32_to_cpu(m->hdr.data_len) > 0) {
 		/* initialize page iterator */
 		con->out_msg_pos.page = 0;
-		con->out_msg_pos.page_pos =
-			le16_to_cpu(m->hdr.data_off) & ~PAGE_MASK;
+		if (m->pages)
+			con->out_msg_pos.page_pos =
+				le16_to_cpu(m->hdr.data_off) & ~PAGE_MASK;
+		else
+			con->out_msg_pos.page_pos = 0;
 		con->out_msg_pos.data_pos = 0;
 		con->out_msg_pos.did_page_crc = 0;
 		con->out_more = 1;  /* data + footer will follow */
@@ -722,6 +727,31 @@ out:
 	return ret;  /* done! */
 }
 
+#ifdef CONFIG_BLOCK
+static void init_bio_iter(struct bio *bio, struct bio **iter, int *seg)
+{
+	if (!bio) {
+		*iter = NULL;
+		*seg = 0;
+		return;
+	}
+	*iter = bio;
+	*seg = bio->bi_idx;
+}
+
+static void iter_bio_next(struct bio **bio_iter, int *seg)
+{
+	if (*bio_iter == NULL)
+		return;
+
+	BUG_ON(*seg >= (*bio_iter)->bi_vcnt);
+
+	(*seg)++;
+	if (*seg == (*bio_iter)->bi_vcnt)
+		init_bio_iter((*bio_iter)->bi_next, bio_iter, seg);
+}
+#endif
+
 /*
  * Write as much message data payload as we can.  If we finish, queue
  * up the footer.
@@ -741,9 +771,16 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 	     con, con->out_msg, con->out_msg_pos.page, con->out_msg->nr_pages,
 	     con->out_msg_pos.page_pos);
 
-	while (con->out_msg_pos.page < con->out_msg->nr_pages) {
+#ifdef CONFIG_BLOCK
+	if (msg->bio && !msg->bio_iter)
+		init_bio_iter(msg->bio, &msg->bio_iter, &msg->bio_seg);
+#endif
+
+	while (data_len - con->out_msg_pos.data_pos > 0) {
 		struct page *page = NULL;
 		void *kaddr = NULL;
+		int max_write = PAGE_SIZE;
+		int page_shift = 0;
 
 		/*
 		 * if we are calculating the data crc (the default), we need
@@ -759,13 +796,24 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 						struct page, lru);
 			if (crc)
 				kaddr = kmap(page);
+#ifdef CONFIG_BLOCK
+		} else if (msg->bio) {
+			struct bio_vec *bv;
+
+			bv = bio_iovec_idx(msg->bio_iter, msg->bio_seg);
+			page = bv->bv_page;
+			page_shift = bv->bv_offset;
+			if (crc)
+				kaddr = kmap(page) + page_shift;
+			max_write = bv->bv_len;
+#endif
 		} else {
 			page = con->msgr->zero_page;
 			if (crc)
 				kaddr = page_address(con->msgr->zero_page);
 		}
-		len = min((int)(PAGE_SIZE - con->out_msg_pos.page_pos),
-			  (int)(data_len - con->out_msg_pos.data_pos));
+		len = min_t(int, max_write - con->out_msg_pos.page_pos,
+			    data_len - con->out_msg_pos.data_pos);
 		if (crc && !con->out_msg_pos.did_page_crc) {
 			void *base = kaddr + con->out_msg_pos.page_pos;
 			u32 tmpcrc = le32_to_cpu(con->out_msg->footer.data_crc);
@@ -777,11 +825,12 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 		}
 
 		ret = kernel_sendpage(con->sock, page,
-				      con->out_msg_pos.page_pos, len,
+				      con->out_msg_pos.page_pos + page_shift,
+				      len,
 				      MSG_DONTWAIT | MSG_NOSIGNAL |
 				      MSG_MORE);
 
-		if (crc && (msg->pages || msg->pagelist))
+		if (crc && (msg->pages || msg->pagelist || msg->bio))
 			kunmap(page);
 
 		if (ret <= 0)
@@ -796,6 +845,10 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 			if (msg->pagelist)
 				list_move_tail(&page->lru,
 					       &msg->pagelist->head);
+#ifdef CONFIG_BLOCK
+			if (msg->bio)
+				iter_bio_next(&msg->bio_iter, &msg->bio_seg);
+#endif
 		}
 	}
 
@@ -1302,8 +1355,7 @@ static int read_partial_message_section(struct ceph_connection *con,
 					struct kvec *section, unsigned int sec_len,
 					u32 *crc)
 {
-	int left;
-	int ret;
+	int ret, left;
 
 	BUG_ON(!section);
 
@@ -1326,13 +1378,83 @@ static int read_partial_message_section(struct ceph_connection *con,
 static struct ceph_msg *ceph_alloc_msg(struct ceph_connection *con,
 				struct ceph_msg_header *hdr,
 				int *skip);
+
+
+static int read_partial_message_pages(struct ceph_connection *con,
+				      struct page **pages,
+				      unsigned data_len, int datacrc)
+{
+	void *p;
+	int ret;
+	int left;
+
+	left = min((int)(data_len - con->in_msg_pos.data_pos),
+		   (int)(PAGE_SIZE - con->in_msg_pos.page_pos));
+	/* (page) data */
+	BUG_ON(pages == NULL);
+	p = kmap(pages[con->in_msg_pos.page]);
+	ret = ceph_tcp_recvmsg(con->sock, p + con->in_msg_pos.page_pos,
+			       left);
+	if (ret > 0 && datacrc)
+		con->in_data_crc =
+			crc32c(con->in_data_crc,
+				  p + con->in_msg_pos.page_pos, ret);
+	kunmap(pages[con->in_msg_pos.page]);
+	if (ret <= 0)
+		return ret;
+	con->in_msg_pos.data_pos += ret;
+	con->in_msg_pos.page_pos += ret;
+	if (con->in_msg_pos.page_pos == PAGE_SIZE) {
+		con->in_msg_pos.page_pos = 0;
+		con->in_msg_pos.page++;
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_BLOCK
+static int read_partial_message_bio(struct ceph_connection *con,
+				    struct bio **bio_iter, int *bio_seg,
+				    unsigned data_len, int datacrc)
+{
+	struct bio_vec *bv = bio_iovec_idx(*bio_iter, *bio_seg);
+	void *p;
+	int ret, left;
+
+	if (IS_ERR(bv))
+		return PTR_ERR(bv);
+
+	left = min((int)(data_len - con->in_msg_pos.data_pos),
+		   (int)(bv->bv_len - con->in_msg_pos.page_pos));
+
+	p = kmap(bv->bv_page) + bv->bv_offset;
+
+	ret = ceph_tcp_recvmsg(con->sock, p + con->in_msg_pos.page_pos,
+			       left);
+	if (ret > 0 && datacrc)
+		con->in_data_crc =
+			crc32c(con->in_data_crc,
+				  p + con->in_msg_pos.page_pos, ret);
+	kunmap(bv->bv_page);
+	if (ret <= 0)
+		return ret;
+	con->in_msg_pos.data_pos += ret;
+	con->in_msg_pos.page_pos += ret;
+	if (con->in_msg_pos.page_pos == bv->bv_len) {
+		con->in_msg_pos.page_pos = 0;
+		iter_bio_next(bio_iter, bio_seg);
+	}
+
+	return ret;
+}
+#endif
+
 /*
  * read (part of) a message.
  */
 static int read_partial_message(struct ceph_connection *con)
 {
 	struct ceph_msg *m = con->in_msg;
-	void *p;
 	int ret;
 	int to, left;
 	unsigned front_len, middle_len, data_len, data_off;
@@ -1417,7 +1539,10 @@ static int read_partial_message(struct ceph_connection *con)
 			m->middle->vec.iov_len = 0;
 
 		con->in_msg_pos.page = 0;
-		con->in_msg_pos.page_pos = data_off & ~PAGE_MASK;
+		if (m->pages)
+			con->in_msg_pos.page_pos = data_off & ~PAGE_MASK;
+		else
+			con->in_msg_pos.page_pos = 0;
 		con->in_msg_pos.data_pos = 0;
 	}
 
@@ -1434,27 +1559,29 @@ static int read_partial_message(struct ceph_connection *con)
 		if (ret <= 0)
 			return ret;
 	}
+#ifdef CONFIG_BLOCK
+	if (m->bio && !m->bio_iter)
+		init_bio_iter(m->bio, &m->bio_iter, &m->bio_seg);
+#endif
 
 	/* (page) data */
 	while (con->in_msg_pos.data_pos < data_len) {
-		left = min((int)(data_len - con->in_msg_pos.data_pos),
-			   (int)(PAGE_SIZE - con->in_msg_pos.page_pos));
-		BUG_ON(m->pages == NULL);
-		p = kmap(m->pages[con->in_msg_pos.page]);
-		ret = ceph_tcp_recvmsg(con->sock, p + con->in_msg_pos.page_pos,
-				       left);
-		if (ret > 0 && datacrc)
-			con->in_data_crc =
-				crc32c(con->in_data_crc,
-					  p + con->in_msg_pos.page_pos, ret);
-		kunmap(m->pages[con->in_msg_pos.page]);
-		if (ret <= 0)
-			return ret;
-		con->in_msg_pos.data_pos += ret;
-		con->in_msg_pos.page_pos += ret;
-		if (con->in_msg_pos.page_pos == PAGE_SIZE) {
-			con->in_msg_pos.page_pos = 0;
-			con->in_msg_pos.page++;
+		if (m->pages) {
+			ret = read_partial_message_pages(con, m->pages,
+						 data_len, datacrc);
+			if (ret <= 0)
+				return ret;
+#ifdef CONFIG_BLOCK
+		} else if (m->bio) {
+
+			ret = read_partial_message_bio(con,
+						 &m->bio_iter, &m->bio_seg,
+						 data_len, datacrc);
+			if (ret <= 0)
+				return ret;
+#endif
+		} else {
+			BUG_ON(1);
 		}
 	}
 
@@ -2130,6 +2257,9 @@ struct ceph_msg *ceph_msg_new(int type, int front_len, gfp_t flags)
 	m->nr_pages = 0;
 	m->pages = NULL;
 	m->pagelist = NULL;
+	m->bio = NULL;
+	m->bio_iter = NULL;
+	m->bio_seg = 0;
 
 	dout("ceph_msg_new %p front %d\n", m, front_len);
 	return m;
diff --git a/fs/ceph/messenger.h b/fs/ceph/messenger.h
index 76fbc957bc13..aea42b9fbee3 100644
--- a/fs/ceph/messenger.h
+++ b/fs/ceph/messenger.h
@@ -82,6 +82,9 @@ struct ceph_msg {
 	struct ceph_pagelist *pagelist; /* instead of pages */
 	struct list_head list_head;
 	struct kref kref;
+	struct bio  *bio;		/* instead of pages/pagelist */
+	struct bio  *bio_iter;		/* bio iterator */
+	int bio_seg;			/* current bio segment */
 	bool front_is_vmalloc;
 	bool more_to_follow;
 	bool needs_out_seq;
diff --git a/fs/ceph/mon_client.c b/fs/ceph/mon_client.c
index 21c62e9b7d1d..b319b91fb60a 100644
--- a/fs/ceph/mon_client.c
+++ b/fs/ceph/mon_client.c
@@ -349,7 +349,7 @@ out:
 }
 
 /*
- * statfs
+ * generic requests (e.g., statfs, poolop)
  */
 static struct ceph_mon_generic_request *__lookup_generic_req(
 	struct ceph_mon_client *monc, u64 tid)
@@ -440,6 +440,35 @@ static struct ceph_msg *get_generic_reply(struct ceph_connection *con,
 	return m;
 }
 
+static int do_generic_request(struct ceph_mon_client *monc,
+			      struct ceph_mon_generic_request *req)
+{
+	int err;
+
+	/* register request */
+	mutex_lock(&monc->mutex);
+	req->tid = ++monc->last_tid;
+	req->request->hdr.tid = cpu_to_le64(req->tid);
+	__insert_generic_request(monc, req);
+	monc->num_generic_requests++;
+	ceph_con_send(monc->con, ceph_msg_get(req->request));
+	mutex_unlock(&monc->mutex);
+
+	err = wait_for_completion_interruptible(&req->completion);
+
+	mutex_lock(&monc->mutex);
+	rb_erase(&req->node, &monc->generic_request_tree);
+	monc->num_generic_requests--;
+	mutex_unlock(&monc->mutex);
+
+	if (!err)
+		err = req->result;
+	return err;
+}
+
+/*
+ * statfs
+ */
 static void handle_statfs_reply(struct ceph_mon_client *monc,
 				struct ceph_msg *msg)
 {
@@ -466,7 +495,7 @@ static void handle_statfs_reply(struct ceph_mon_client *monc,
 	return;
 
 bad:
-	pr_err("corrupt generic reply, no tid\n");
+	pr_err("corrupt generic reply, tid %llu\n", tid);
 	ceph_msg_dump(msg);
 }
 
@@ -485,6 +514,7 @@ int ceph_monc_do_statfs(struct ceph_mon_client *monc, struct ceph_statfs *buf)
 
 	kref_init(&req->kref);
 	req->buf = buf;
+	req->buf_len = sizeof(*buf);
 	init_completion(&req->completion);
 
 	err = -ENOMEM;
@@ -502,33 +532,134 @@ int ceph_monc_do_statfs(struct ceph_mon_client *monc, struct ceph_statfs *buf)
 	h->monhdr.session_mon_tid = 0;
 	h->fsid = monc->monmap->fsid;
 
-	/* register request */
-	mutex_lock(&monc->mutex);
-	req->tid = ++monc->last_tid;
-	req->request->hdr.tid = cpu_to_le64(req->tid);
-	__insert_generic_request(monc, req);
-	monc->num_generic_requests++;
-	mutex_unlock(&monc->mutex);
+	err = do_generic_request(monc, req);
 
-	/* send request and wait */
-	ceph_con_send(monc->con, ceph_msg_get(req->request));
-	err = wait_for_completion_interruptible(&req->completion);
+out:
+	kref_put(&req->kref, release_generic_request);
+	return err;
+}
+
+/*
+ * pool ops
+ */
+static int get_poolop_reply_buf(const char *src, size_t src_len,
+				char *dst, size_t dst_len)
+{
+	u32 buf_len;
+
+	if (src_len != sizeof(u32) + dst_len)
+		return -EINVAL;
+
+	buf_len = le32_to_cpu(*(u32 *)src);
+	if (buf_len != dst_len)
+		return -EINVAL;
+
+	memcpy(dst, src + sizeof(u32), dst_len);
+	return 0;
+}
+
+static void handle_poolop_reply(struct ceph_mon_client *monc,
+				struct ceph_msg *msg)
+{
+	struct ceph_mon_generic_request *req;
+	struct ceph_mon_poolop_reply *reply = msg->front.iov_base;
+	u64 tid = le64_to_cpu(msg->hdr.tid);
+
+	if (msg->front.iov_len < sizeof(*reply))
+		goto bad;
+	dout("handle_poolop_reply %p tid %llu\n", msg, tid);
 
 	mutex_lock(&monc->mutex);
-	rb_erase(&req->node, &monc->generic_request_tree);
-	monc->num_generic_requests--;
+	req = __lookup_generic_req(monc, tid);
+	if (req) {
+		if (req->buf_len &&
+		    get_poolop_reply_buf(msg->front.iov_base + sizeof(*reply),
+				     msg->front.iov_len - sizeof(*reply),
+				     req->buf, req->buf_len) < 0) {
+			mutex_unlock(&monc->mutex);
+			goto bad;
+		}
+		req->result = le32_to_cpu(reply->reply_code);
+		get_generic_request(req);
+	}
 	mutex_unlock(&monc->mutex);
+	if (req) {
+		complete(&req->completion);
+		put_generic_request(req);
+	}
+	return;
 
-	if (!err)
-		err = req->result;
+bad:
+	pr_err("corrupt generic reply, tid %llu\n", tid);
+	ceph_msg_dump(msg);
+}
+
+/*
+ * Do a synchronous pool op.
+ */
+int ceph_monc_do_poolop(struct ceph_mon_client *monc, u32 op,
+			u32 pool, u64 snapid,
+			char *buf, int len)
+{
+	struct ceph_mon_generic_request *req;
+	struct ceph_mon_poolop *h;
+	int err;
+
+	req = kzalloc(sizeof(*req), GFP_NOFS);
+	if (!req)
+		return -ENOMEM;
+
+	kref_init(&req->kref);
+	req->buf = buf;
+	req->buf_len = len;
+	init_completion(&req->completion);
+
+	err = -ENOMEM;
+	req->request = ceph_msg_new(CEPH_MSG_POOLOP, sizeof(*h), GFP_NOFS);
+	if (!req->request)
+		goto out;
+	req->reply = ceph_msg_new(CEPH_MSG_POOLOP_REPLY, 1024, GFP_NOFS);
+	if (!req->reply)
+		goto out;
+
+	/* fill out request */
+	req->request->hdr.version = cpu_to_le16(2);
+	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->pool = cpu_to_le32(pool);
+	h->op = cpu_to_le32(op);
+	h->auid = 0;
+	h->snapid = cpu_to_le64(snapid);
+	h->name_len = 0;
+
+	err = do_generic_request(monc, req);
 
 out:
 	kref_put(&req->kref, release_generic_request);
 	return err;
 }
 
+int ceph_monc_create_snapid(struct ceph_mon_client *monc,
+			    u32 pool, u64 *snapid)
+{
+	return ceph_monc_do_poolop(monc,  POOL_OP_CREATE_UNMANAGED_SNAP,
+				   pool, 0, (char *)snapid, sizeof(*snapid));
+
+}
+
+int ceph_monc_delete_snapid(struct ceph_mon_client *monc,
+			    u32 pool, u64 snapid)
+{
+	return ceph_monc_do_poolop(monc,  POOL_OP_CREATE_UNMANAGED_SNAP,
+				   pool, snapid, 0, 0);
+
+}
+
 /*
- * Resend pending statfs requests.
+ * Resend pending generic requests.
  */
 static void __resend_generic_request(struct ceph_mon_client *monc)
 {
@@ -780,12 +911,17 @@ static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
 		handle_statfs_reply(monc, msg);
 		break;
 
+	case CEPH_MSG_POOLOP_REPLY:
+		handle_poolop_reply(monc, msg);
+		break;
+
 	case CEPH_MSG_MON_MAP:
 		ceph_monc_handle_map(monc, msg);
 		break;
 
 	case CEPH_MSG_MDS_MAP:
-		ceph_mdsc_handle_map(&monc->client->mdsc, msg);
+		if (monc->client->have_mdsc)
+			ceph_mdsc_handle_map(&monc->client->mdsc, msg);
 		break;
 
 	case CEPH_MSG_OSD_MAP:
@@ -817,6 +953,7 @@ static struct ceph_msg *mon_alloc_msg(struct ceph_connection *con,
 	case CEPH_MSG_MON_SUBSCRIBE_ACK:
 		m = ceph_msg_get(monc->m_subscribe_ack);
 		break;
+	case CEPH_MSG_POOLOP_REPLY:
 	case CEPH_MSG_STATFS_REPLY:
 		return get_generic_reply(con, hdr, skip);
 	case CEPH_MSG_AUTH_REPLY:
diff --git a/fs/ceph/mon_client.h b/fs/ceph/mon_client.h
index 174d794321d0..8e396f2c0963 100644
--- a/fs/ceph/mon_client.h
+++ b/fs/ceph/mon_client.h
@@ -50,6 +50,7 @@ struct ceph_mon_generic_request {
 	struct rb_node node;
 	int result;
 	void *buf;
+	int buf_len;
 	struct completion completion;
 	struct ceph_msg *request;  /* original request */
 	struct ceph_msg *reply;    /* and reply */
@@ -111,6 +112,10 @@ extern int ceph_monc_open_session(struct ceph_mon_client *monc);
 
 extern int ceph_monc_validate_auth(struct ceph_mon_client *monc);
 
+extern int ceph_monc_create_snapid(struct ceph_mon_client *monc,
+				   u32 pool, u64 *snapid);
 
+extern int ceph_monc_delete_snapid(struct ceph_mon_client *monc,
+				   u32 pool, u64 snapid);
 
 #endif
diff --git a/fs/ceph/osd_client.c b/fs/ceph/osd_client.c
index d25b4add85b4..d7515e89573f 100644
--- a/fs/ceph/osd_client.c
+++ b/fs/ceph/osd_client.c
@@ -6,6 +6,9 @@
 #include <linux/pagemap.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
+#ifdef CONFIG_BLOCK
+#include <linux/bio.h>
+#endif
 
 #include "super.h"
 #include "osd_client.h"
@@ -22,6 +25,35 @@ static int __kick_requests(struct ceph_osd_client *osdc,
 
 static void kick_requests(struct ceph_osd_client *osdc, struct ceph_osd *osd);
 
+void ceph_calc_raw_layout(struct ceph_osd_client *osdc,
+			struct ceph_file_layout *layout,
+			u64 snapid,
+			u64 off, u64 len, u64 *bno,
+			struct ceph_osd_request *req)
+{
+	struct ceph_osd_request_head *reqhead = req->r_request->front.iov_base;
+	struct ceph_osd_op *op = (void *)(reqhead + 1);
+	u64 orig_len = len;
+	u64 objoff, objlen;    /* extent in object */
+
+	reqhead->snapid = cpu_to_le64(snapid);
+
+	/* object extent? */
+	ceph_calc_file_object_mapping(layout, off, &len, bno,
+				      &objoff, &objlen);
+	if (len < orig_len)
+		dout(" skipping last %llu, final file extent %llu~%llu\n",
+		     orig_len - len, off, len);
+
+	op->extent.offset = cpu_to_le64(objoff);
+	op->extent.length = cpu_to_le64(objlen);
+	req->r_num_pages = calc_pages_for(off, len);
+
+	dout("calc_layout bno=%llx %llu~%llu (%d pages)\n",
+	     *bno, objoff, objlen, req->r_num_pages);
+
+}
+
 /*
  * Implement client access to distributed object storage cluster.
  *
@@ -48,34 +80,17 @@ static void kick_requests(struct ceph_osd_client *osdc, struct ceph_osd *osd);
  * fill osd op in request message.
  */
 static void calc_layout(struct ceph_osd_client *osdc,
-			struct ceph_vino vino, struct ceph_file_layout *layout,
+			struct ceph_vino vino,
+			struct ceph_file_layout *layout,
 			u64 off, u64 *plen,
 			struct ceph_osd_request *req)
 {
-	struct ceph_osd_request_head *reqhead = req->r_request->front.iov_base;
-	struct ceph_osd_op *op = (void *)(reqhead + 1);
-	u64 orig_len = *plen;
-	u64 objoff, objlen;    /* extent in object */
 	u64 bno;
 
-	reqhead->snapid = cpu_to_le64(vino.snap);
-
-	/* object extent? */
-	ceph_calc_file_object_mapping(layout, off, plen, &bno,
-				      &objoff, &objlen);
-	if (*plen < orig_len)
-		dout(" skipping last %llu, final file extent %llu~%llu\n",
-		     orig_len - *plen, off, *plen);
+	ceph_calc_raw_layout(osdc, layout, vino.snap, off, *plen, &bno, req);
 
 	sprintf(req->r_oid, "%llx.%08llx", vino.ino, bno);
 	req->r_oid_len = strlen(req->r_oid);
-
-	op->extent.offset = cpu_to_le64(objoff);
-	op->extent.length = cpu_to_le64(objlen);
-	req->r_num_pages = calc_pages_for(off, *plen);
-
-	dout("calc_layout %s (%d) %llu~%llu (%d pages)\n",
-	     req->r_oid, req->r_oid_len, objoff, objlen, req->r_num_pages);
 }
 
 /*
@@ -101,6 +116,10 @@ void ceph_osdc_release_request(struct kref *kref)
 	if (req->r_own_pages)
 		ceph_release_page_vector(req->r_pages,
 					 req->r_num_pages);
+#ifdef CONFIG_BLOCK
+	if (req->r_bio)
+		bio_put(req->r_bio);
+#endif
 	ceph_put_snap_context(req->r_snapc);
 	if (req->r_mempool)
 		mempool_free(req, req->r_osdc->req_mempool);
@@ -108,43 +127,35 @@ void ceph_osdc_release_request(struct kref *kref)
 		kfree(req);
 }
 
-/*
- * build new request AND message, calculate layout, and adjust file
- * extent as needed.
- *
- * if the file was recently truncated, we include information about its
- * old and new size so that the object can be updated appropriately.  (we
- * avoid synchronously deleting truncated objects because it's slow.)
- *
- * if @do_sync, include a 'startsync' command so that the osd will flush
- * data quickly.
- */
-struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
-					       struct ceph_file_layout *layout,
-					       struct ceph_vino vino,
-					       u64 off, u64 *plen,
-					       int opcode, int flags,
+struct ceph_osd_request *ceph_osdc_alloc_request(struct ceph_osd_client *osdc,
+					       int flags,
 					       struct ceph_snap_context *snapc,
 					       int do_sync,
-					       u32 truncate_seq,
-					       u64 truncate_size,
-					       struct timespec *mtime,
-					       bool use_mempool, int num_reply)
+					       bool use_mempool,
+					       gfp_t gfp_flags,
+					       struct page **pages,
+					       struct bio *bio)
 {
 	struct ceph_osd_request *req;
 	struct ceph_msg *msg;
-	struct ceph_osd_request_head *head;
-	struct ceph_osd_op *op;
-	void *p;
 	int num_op = 1 + do_sync;
-	size_t msg_size = sizeof(*head) + num_op*sizeof(*op);
-	int i;
+	size_t msg_size = sizeof(struct ceph_osd_request_head) +
+			  num_op*sizeof(struct ceph_osd_op);
+
+	if (use_mempool) {
+		req = mempool_alloc(osdc->req_mempool, gfp_flags);
+		memset(req, 0, sizeof(*req));
+	} else {
+		req = kzalloc(sizeof(*req), gfp_flags);
+	}
+	if (!req)
+		return NULL;
 
 	if (use_mempool) {
-		req = mempool_alloc(osdc->req_mempool, GFP_NOFS);
+		req = mempool_alloc(osdc->req_mempool, gfp_flags);
 		memset(req, 0, sizeof(*req));
 	} else {
-		req = kzalloc(sizeof(*req), GFP_NOFS);
+		req = kzalloc(sizeof(*req), gfp_flags);
 	}
 	if (req == NULL)
 		return NULL;
@@ -164,7 +175,7 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
 		msg = ceph_msgpool_get(&osdc->msgpool_op_reply, 0);
 	else
 		msg = ceph_msg_new(CEPH_MSG_OSD_OPREPLY,
-				   OSD_OPREPLY_FRONT_LEN, GFP_NOFS);
+				   OSD_OPREPLY_FRONT_LEN, gfp_flags);
 	if (!msg) {
 		ceph_osdc_put_request(req);
 		return NULL;
@@ -178,18 +189,54 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
 	if (use_mempool)
 		msg = ceph_msgpool_get(&osdc->msgpool_op, 0);
 	else
-		msg = ceph_msg_new(CEPH_MSG_OSD_OP, msg_size, GFP_NOFS);
+		msg = ceph_msg_new(CEPH_MSG_OSD_OP, msg_size, gfp_flags);
 	if (!msg) {
 		ceph_osdc_put_request(req);
 		return NULL;
 	}
 	msg->hdr.type = cpu_to_le16(CEPH_MSG_OSD_OP);
 	memset(msg->front.iov_base, 0, msg->front.iov_len);
+
+	req->r_request = msg;
+	req->r_pages = pages;
+#ifdef CONFIG_BLOCK
+	if (bio) {
+		req->r_bio = bio;
+		bio_get(req->r_bio);
+	}
+#endif
+
+	return req;
+}
+
+/*
+ * build new request AND message
+ *
+ */
+void ceph_osdc_build_request(struct ceph_osd_request *req,
+			    u64 off, u64 *plen,
+			    int opcode,
+			    struct ceph_snap_context *snapc,
+			    int do_sync,
+			    u32 truncate_seq,
+			    u64 truncate_size,
+			    struct timespec *mtime,
+			    const char *oid,
+			    int oid_len)
+{
+	struct ceph_msg *msg = req->r_request;
+	struct ceph_osd_request_head *head;
+	struct ceph_osd_op *op;
+	void *p;
+	int num_op = 1 + do_sync;
+	size_t msg_size = sizeof(*head) + num_op*sizeof(*op);
+	int i;
+	int flags = req->r_flags;
+
 	head = msg->front.iov_base;
 	op = (void *)(head + 1);
 	p = (void *)(op + num_op);
 
-	req->r_request = msg;
 	req->r_snapc = ceph_get_snap_context(snapc);
 
 	head->client_inc = cpu_to_le32(1); /* always, for now. */
@@ -199,10 +246,6 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
 	head->num_ops = cpu_to_le16(num_op);
 	op->op = cpu_to_le16(opcode);
 
-	/* calculate max write size */
-	calc_layout(osdc, vino, layout, off, plen, req);
-	req->r_file_layout = *layout;  /* keep a copy */
-
 	if (flags & CEPH_OSD_FLAG_WRITE) {
 		req->r_request->hdr.data_off = cpu_to_le16(off);
 		req->r_request->hdr.data_len = cpu_to_le32(*plen);
@@ -212,9 +255,9 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
 	op->extent.truncate_seq = cpu_to_le32(truncate_seq);
 
 	/* fill in oid */
-	head->object_len = cpu_to_le32(req->r_oid_len);
-	memcpy(p, req->r_oid, req->r_oid_len);
-	p += req->r_oid_len;
+	head->object_len = cpu_to_le32(oid_len);
+	memcpy(p, oid, oid_len);
+	p += oid_len;
 
 	if (do_sync) {
 		op++;
@@ -233,6 +276,50 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
 	msg_size = p - msg->front.iov_base;
 	msg->front.iov_len = msg_size;
 	msg->hdr.front_len = cpu_to_le32(msg_size);
+	return;
+}
+
+/*
+ * build new request AND message, calculate layout, and adjust file
+ * extent as needed.
+ *
+ * if the file was recently truncated, we include information about its
+ * old and new size so that the object can be updated appropriately.  (we
+ * avoid synchronously deleting truncated objects because it's slow.)
+ *
+ * if @do_sync, include a 'startsync' command so that the osd will flush
+ * data quickly.
+ */
+struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
+					       struct ceph_file_layout *layout,
+					       struct ceph_vino vino,
+					       u64 off, u64 *plen,
+					       int opcode, int flags,
+					       struct ceph_snap_context *snapc,
+					       int do_sync,
+					       u32 truncate_seq,
+					       u64 truncate_size,
+					       struct timespec *mtime,
+					       bool use_mempool, int num_reply)
+{
+	struct ceph_osd_request *req =
+		ceph_osdc_alloc_request(osdc, flags,
+					 snapc, do_sync,
+					 use_mempool,
+					 GFP_NOFS, NULL, NULL);
+	if (IS_ERR(req))
+		return req;
+
+	/* calculate max write size */
+	calc_layout(osdc, vino, layout, off, plen, req);
+	req->r_file_layout = *layout;  /* keep a copy */
+
+	ceph_osdc_build_request(req, off, plen, opcode,
+				snapc, do_sync,
+				truncate_seq, truncate_size,
+				mtime,
+				req->r_oid, req->r_oid_len);
+
 	return req;
 }
 
@@ -1104,6 +1191,9 @@ int ceph_osdc_start_request(struct ceph_osd_client *osdc,
 
 	req->r_request->pages = req->r_pages;
 	req->r_request->nr_pages = req->r_num_pages;
+#ifdef CONFIG_BLOCK
+	req->r_request->bio = req->r_bio;
+#endif
 
 	register_request(osdc, req);
 
@@ -1422,6 +1512,9 @@ static struct ceph_msg *get_reply(struct ceph_connection *con,
 		}
 		m->pages = req->r_pages;
 		m->nr_pages = req->r_num_pages;
+#ifdef CONFIG_BLOCK
+		m->bio = req->r_bio;
+#endif
 	}
 	*skip = 0;
 	req->r_con_filling_msg = ceph_con_get(con);
diff --git a/fs/ceph/osd_client.h b/fs/ceph/osd_client.h
index ce776989ef6a..2daa3fcae63e 100644
--- a/fs/ceph/osd_client.h
+++ b/fs/ceph/osd_client.h
@@ -68,6 +68,7 @@ struct ceph_osd_request {
 	struct list_head  r_unsafe_item;
 
 	struct inode *r_inode;         	      /* for use by callbacks */
+	void *r_priv;			      /* ditto */
 
 	char              r_oid[40];          /* object name */
 	int               r_oid_len;
@@ -80,6 +81,9 @@ struct ceph_osd_request {
 	struct page     **r_pages;            /* pages for data payload */
 	int               r_pages_from_pool;
 	int               r_own_pages;        /* if true, i own page list */
+#ifdef CONFIG_BLOCK
+	struct bio       *r_bio;	      /* instead of pages */
+#endif
 };
 
 struct ceph_osd_client {
@@ -119,6 +123,32 @@ extern void ceph_osdc_handle_reply(struct ceph_osd_client *osdc,
 extern void ceph_osdc_handle_map(struct ceph_osd_client *osdc,
 				 struct ceph_msg *msg);
 
+extern void ceph_calc_raw_layout(struct ceph_osd_client *osdc,
+			struct ceph_file_layout *layout,
+			u64 snapid,
+			u64 off, u64 len, u64 *bno,
+			struct ceph_osd_request *req);
+
+extern struct ceph_osd_request *ceph_osdc_alloc_request(struct ceph_osd_client *osdc,
+					       int flags,
+					       struct ceph_snap_context *snapc,
+					       int do_sync,
+					       bool use_mempool,
+					       gfp_t gfp_flags,
+					       struct page **pages,
+					       struct bio *bio);
+
+extern void ceph_osdc_build_request(struct ceph_osd_request *req,
+			    u64 off, u64 *plen,
+			    int opcode,
+			    struct ceph_snap_context *snapc,
+			    int do_sync,
+			    u32 truncate_seq,
+			    u64 truncate_size,
+			    struct timespec *mtime,
+			    const char *oid,
+			    int oid_len);
+
 extern struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *,
 				      struct ceph_file_layout *layout,
 				      struct ceph_vino vino,
diff --git a/fs/ceph/osdmap.c b/fs/ceph/osdmap.c
index ddc656fb5c05..11aac1c60943 100644
--- a/fs/ceph/osdmap.c
+++ b/fs/ceph/osdmap.c
@@ -417,6 +417,19 @@ static struct ceph_pg_pool_info *__lookup_pg_pool(struct rb_root *root, int id)
 	return NULL;
 }
 
+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;
+}
+
 static void __remove_pg_pool(struct rb_root *root, struct ceph_pg_pool_info *pi)
 {
 	rb_erase(&pi->node, root);
diff --git a/fs/ceph/osdmap.h b/fs/ceph/osdmap.h
index 970b547e510d..a592b211be39 100644
--- a/fs/ceph/osdmap.h
+++ b/fs/ceph/osdmap.h
@@ -125,4 +125,6 @@ extern int ceph_calc_pg_acting(struct ceph_osdmap *osdmap, struct ceph_pg pgid,
 extern int ceph_calc_pg_primary(struct ceph_osdmap *osdmap,
 				struct ceph_pg pgid);
 
+extern int ceph_pg_poolid_by_name(struct ceph_osdmap *map, const char *name);
+
 #endif
diff --git a/fs/ceph/rbd.c b/fs/ceph/rbd.c
new file mode 100644
index 000000000000..a745f3f3481c
--- /dev/null
+++ b/fs/ceph/rbd.c
@@ -0,0 +1,1803 @@
+/*
+   rbd.c -- Export ceph rados objects as a Linux block device
+
+
+   based on drivers/block/osdblk.c:
+
+   Copyright 2009 Red Hat, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; see the file COPYING.  If not, write to
+   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+
+
+   Instructions for use
+   --------------------
+
+   1) Map a Linux block device to an existing rbd image.
+
+      Usage: <mon ip addr> <options> <pool name> <rbd image name>
+
+      $ echo "192.168.0.1 name=admin rbd foo" > /sys/class/rbd/add
+
+
+   2) List all active blkdev<->object mappings.
+
+      In this example, we have performed step #1 twice, creating two blkdevs,
+      mapped to two separate rados objects in the rados rbd pool
+
+      $ cat /sys/class/rbd/list
+      0 254 rbd foo
+      1 253 rbd bar
+
+      The columns, in order, are:
+      - blkdev unique id
+      - blkdev assigned major
+      - rados pool name
+      - rados block device name
+
+
+   3) Remove an active blkdev<->rbd image mapping.
+
+      In this example, we remove the mapping with blkdev unique id 1.
+
+      $ echo 1 > /sys/class/rbd/remove
+
+
+   NOTE:  The actual creation and deletion of rados objects is outside the scope
+   of this driver.
+
+ */
+
+#include "super.h"
+#include "osd_client.h"
+#include "rbd_types.h"
+#include "mon_client.h"
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+
+#define DRV_NAME "rbd"
+#define DRV_NAME_LONG "rbd (rados block device)"
+
+enum {
+	RBD_MINORS_PER_MAJOR	= 256,		/* max minors per blkdev */
+};
+
+#define RBD_MAX_POOL_NAME_SIZE	64
+
+#define RBD_STRIPE_UNIT (1 << 22)
+
+#define RBD_MAX_OPT_LEN		1024
+#define RBD_MAX_SNAP_NAME_LEN	32
+
+#define RBD_SNAP_OP_CREATE	0x1
+#define RBD_SNAP_OP_SET		0x2
+
+#define RBD_SNAP_HEAD_NAME	"head"
+
+struct rbd_obj_header {
+	u64 image_size;
+	__u8 obj_order;
+	__u8 crypt_type;
+	__u8 comp_type;
+	struct rw_semaphore snap_rwsem;
+	struct ceph_snap_context *snapc;
+	size_t snap_names_len;
+	u32 snap_seq;
+	u32 total_snaps;
+
+	char *snap_names;
+	u64 *snap_sizes;
+};
+
+struct rbd_request {
+	struct request		*rq;		/* blk layer request */
+	struct bio		*bio;		/* cloned bio */
+	struct page		**pages;	/* list of used pages */
+	u64			len;
+};
+
+struct rbd_client_node {
+	struct ceph_client	*client;
+	const char		*opt;
+	struct kref		kref;
+	struct list_head	node;
+};
+
+#define DEV_NAME_LEN		32
+
+struct rbd_device {
+	int			id;		/* blkdev unique id */
+
+	int			major;		/* blkdev assigned major */
+	struct gendisk		*disk;		/* blkdev's gendisk and rq */
+	struct request_queue	*q;
+
+	struct ceph_client	*client;	/* associated OSD */
+
+	char			name[DEV_NAME_LEN]; /* blkdev name, e.g. rbd3 */
+
+	spinlock_t		lock;		/* queue lock */
+
+	struct rbd_obj_header	header;
+	char			obj[RBD_MAX_OBJ_NAME_SIZE]; /* rbd image name */
+	int			obj_len;
+	char			pool_name[RBD_MAX_POOL_NAME_SIZE];
+	int			poolid;
+
+	u32 cur_snap;	/* index+1 of current snapshot within snap context
+			   0 - for the head */
+	int read_only;
+
+	struct list_head	node;
+	struct rbd_client_node	*client_node;
+};
+
+static spinlock_t node_lock; /* protects client get/put */
+
+static struct class *class_rbd;		/* /sys/class/rbd */
+static DEFINE_MUTEX(ctl_mutex);	/* Serialize open/close/setup/teardown */
+static LIST_HEAD(rbddev_list);
+static LIST_HEAD(node_list);
+
+
+static int rbd_open(struct block_device *bdev, fmode_t mode)
+{
+	struct gendisk *disk = bdev->bd_disk;
+	struct rbd_device *rbd_dev = disk->private_data;
+
+	if (mode & FMODE_WRITE && rbd_dev->read_only)
+		return -EROFS;
+
+	return 0;
+}
+
+static const struct block_device_operations rbd_bd_ops = {
+	.owner			= THIS_MODULE,
+	.open			= rbd_open,
+};
+
+/*
+ * Initialize ceph client for a specific device.
+ */
+static int rbd_init_client(struct rbd_device *rbd_dev,
+			   struct ceph_mount_args *args)
+{
+	struct ceph_osd_client *osdc;
+	int ret;
+	dout("rbd_init_device\n");
+	rbd_dev->client = ceph_create_client(args, 0);
+	if (IS_ERR(rbd_dev->client))
+		return PTR_ERR(rbd_dev->client);
+
+	ret = ceph_open_session(rbd_dev->client);
+	if (ret < 0)
+		goto done_err;
+
+	osdc = &rbd_dev->client->osdc;
+	ret = ceph_pg_poolid_by_name(osdc->osdmap,
+				     rbd_dev->pool_name);
+	if (ret < 0)
+		goto done_err;
+
+	rbd_dev->poolid = ret;
+	return 0;
+
+done_err:
+	ceph_destroy_client(rbd_dev->client);
+	rbd_dev->client = NULL;
+	return ret;
+}
+
+/*
+ * Find a ceph client with specific addr and configuration.
+ */
+static struct rbd_client_node *__get_client_node(struct ceph_mount_args *args)
+{
+	struct rbd_client_node *client_node;
+
+	if (args->flags & CEPH_OPT_NOSHARE)
+		return NULL;
+
+	list_for_each_entry(client_node, &node_list, node)
+		if (ceph_compare_mount_args(args, client_node->client) == 0)
+			return client_node;
+	return NULL;
+}
+
+/*
+ * Get a ceph client with specific addr and configuration, if one does
+ * not exist create it.
+ */
+static int rbd_get_client(struct rbd_device *rbd_dev, const char *mon_addr,
+			  char *opt)
+{
+	struct rbd_client_node *client_node;
+	struct ceph_mount_args *args;
+	int ret;
+
+
+	args = parse_mount_args(0, opt, mon_addr, NULL);
+	if (IS_ERR(args))
+		return PTR_ERR(args);
+
+	spin_lock(&node_lock);
+
+	client_node = __get_client_node(args);
+	if (client_node) {
+		ceph_destroy_mount_args(args);
+
+		kref_get(&client_node->kref);
+		rbd_dev->client_node = client_node;
+		rbd_dev->client = client_node->client;
+		spin_unlock(&node_lock);
+		return 0;
+	}
+
+	spin_unlock(&node_lock);
+
+	ret = -ENOMEM;
+	client_node = kmalloc(sizeof(struct rbd_client_node), GFP_KERNEL);
+	if (!client_node)
+		goto out_args;
+
+	ret = rbd_init_client(rbd_dev, args);
+	if (ret < 0)
+		goto out_free;
+
+	client_node->client = rbd_dev->client;
+	client_node->opt = kstrdup(opt, GFP_KERNEL);
+	kref_init(&client_node->kref);
+	INIT_LIST_HEAD(&client_node->node);
+
+	rbd_dev->client_node = client_node;
+
+	spin_lock(&node_lock);
+	list_add_tail(&client_node->node, &node_list);
+	spin_unlock(&node_lock);
+
+	return 0;
+
+out_free:
+	kfree(client_node);
+out_args:
+	ceph_destroy_mount_args(args);
+	return ret;
+}
+
+/*
+ * Destroy ceph client
+ */
+static void rbd_release_client(struct kref *kref)
+{
+	struct rbd_client_node *node =
+			container_of(kref, struct rbd_client_node, kref);
+
+	dout("rbd_release_client\n");
+
+	spin_lock(&node_lock);
+	list_del(&node->node);
+	spin_unlock(&node_lock);
+
+	ceph_destroy_client(node->client);
+	kfree(node->opt);
+	kfree(node);
+}
+
+/*
+ * Drop reference to ceph client node. If it's not referenced anymore, release
+ * it.
+ */
+static void rbd_put_client(struct rbd_device *rbd_dev)
+{
+	if (!rbd_dev->client_node)
+		return;
+
+	kref_put(&rbd_dev->client_node->kref, rbd_release_client);
+	rbd_dev->client_node = NULL;
+}
+
+static int snap_index(struct rbd_obj_header *header, int snap_num)
+{
+	return header->total_snaps - snap_num;
+}
+
+static u64 cur_snap_id(struct rbd_device *rbd_dev)
+{
+	struct rbd_obj_header *header = &rbd_dev->header;
+
+	if (!rbd_dev->cur_snap)
+		return 0;
+
+	return header->snapc->snaps[snap_index(header, rbd_dev->cur_snap)];
+}
+
+
+/*
+ * Create a new header structure, translate header format from the on-disk
+ * header.
+ */
+static int rbd_header_from_disk(struct rbd_obj_header *header,
+				 struct rbd_obj_header_ondisk *ondisk,
+				 int allocated_snaps,
+				 gfp_t gfp_flags)
+{
+	int i;
+	u32 snap_count = le32_to_cpu(ondisk->snap_count);
+	int ret = -ENOMEM;
+
+	init_rwsem(&header->snap_rwsem);
+
+	header->snap_names_len = le64_to_cpu(ondisk->snap_names_len);
+	header->snapc = kmalloc(sizeof(struct ceph_snap_context) +
+				snap_count *
+					sizeof(struct rbd_obj_snap_ondisk),
+				gfp_flags);
+	if (!header->snapc)
+		return -ENOMEM;
+	if (snap_count) {
+		header->snap_names = kmalloc(header->snap_names_len,
+					     GFP_KERNEL);
+		if (!header->snap_names)
+			goto err_snapc;
+		header->snap_sizes = kmalloc(snap_count * sizeof(u64),
+					     GFP_KERNEL);
+		if (!header->snap_sizes)
+			goto err_names;
+	} else {
+		header->snap_names = NULL;
+		header->snap_sizes = NULL;
+	}
+
+	header->image_size = le64_to_cpu(ondisk->image_size);
+	header->obj_order = ondisk->obj_order;
+	header->crypt_type = ondisk->crypt_type;
+	header->comp_type = ondisk->comp_type;
+
+	atomic_set(&header->snapc->nref, 1);
+	header->snap_seq = le32_to_cpu(ondisk->snap_seq);
+	header->snapc->num_snaps = snap_count;
+	header->total_snaps = snap_count;
+
+	if (snap_count &&
+	    allocated_snaps == snap_count) {
+		for (i = 0; i < snap_count; i++) {
+			header->snapc->snaps[i] =
+				le64_to_cpu(ondisk->snaps[i].id);
+			header->snap_sizes[i] =
+				le64_to_cpu(ondisk->snaps[i].image_size);
+		}
+
+		/* copy snapshot names */
+		memcpy(header->snap_names, &ondisk->snaps[i],
+			header->snap_names_len);
+	}
+
+	return 0;
+
+err_names:
+	kfree(header->snap_names);
+err_snapc:
+	kfree(header->snapc);
+	return ret;
+}
+
+/*
+ * Create a new header structure, translate header format from the on-disk
+ * header.
+ */
+static int rbd_header_to_disk(struct rbd_obj_header_ondisk **ondisk,
+			      struct rbd_obj_header_ondisk *old_ondisk,
+			      struct rbd_obj_header *header,
+			      gfp_t gfp_flags)
+{
+	int i;
+
+	down_read(&header->snap_rwsem);
+	*ondisk = kmalloc(sizeof(struct rbd_obj_header_ondisk) +
+				header->snap_names_len +
+				header->total_snaps *
+					sizeof(struct rbd_obj_snap_ondisk),
+				gfp_flags);
+	if (!*ondisk)
+		return -ENOMEM;
+
+	memcpy(*ondisk, old_ondisk, sizeof(*old_ondisk));
+
+	(*ondisk)->snap_seq = cpu_to_le32(header->snap_seq);
+	(*ondisk)->snap_count = cpu_to_le32(header->total_snaps);
+	(*ondisk)->snap_names_len = cpu_to_le64(header->snap_names_len);
+
+	if (header->total_snaps) {
+		for (i = 0; i < header->total_snaps; i++) {
+			(*ondisk)->snaps[i].id =
+				cpu_to_le64(header->snapc->snaps[i]);
+			(*ondisk)->snaps[i].image_size =
+				cpu_to_le64(header->snap_sizes[i]);
+		}
+
+		/* copy snapshot names */
+		memcpy(&(*ondisk)->snaps[i], header->snap_names,
+			header->snap_names_len);
+	}
+	up_read(&header->snap_rwsem);
+
+	return 0;
+}
+
+static int rbd_header_add_snap(struct rbd_device *dev,
+			       const char *snap_name,
+			       gfp_t gfp_flags)
+{
+	struct rbd_obj_header *header = &dev->header;
+	struct ceph_snap_context *new_snapc;
+	char *p;
+	int name_len = strlen(snap_name);
+	u64 *snaps = header->snapc->snaps;
+	u64 *new_sizes;
+	char *new_names;
+	u64 new_snapid;
+	int i;
+	int ret = -EINVAL;
+
+	down_write(&header->snap_rwsem);
+
+	/* we can create a snapshot only if we're pointing at the head */
+	if (dev->cur_snap)
+		goto done;
+
+	ret = -EEXIST;
+	p = header->snap_names;
+	for (i = 0; i < header->total_snaps; i++, p += strlen(p) + 1) {
+		if (strcmp(snap_name, p) == 0)
+			goto done;
+	}
+
+	ret = -ENOMEM;
+	new_snapc = kmalloc(sizeof(struct rbd_obj_header) +
+			    (header->total_snaps + 1) * sizeof(u64),
+			    gfp_flags);
+	if (!new_snapc)
+		goto done;
+	new_names = kmalloc(header->snap_names_len + name_len + 1, gfp_flags);
+	if (!new_names)
+		goto err_snapc;
+	new_sizes = kmalloc((header->total_snaps + 1) * sizeof(u64),
+			    gfp_flags);
+	if (!new_sizes)
+		goto err_names;
+
+	atomic_set(&new_snapc->nref, 1);
+	new_snapc->num_snaps = header->total_snaps + 1;
+	if (header->total_snaps)
+		memcpy(&new_snapc->snaps[1], snaps,
+		       (header->total_snaps) * sizeof(u64));
+
+	ret = ceph_monc_create_snapid(&dev->client->monc, dev->poolid,
+				      &new_snapid);
+	dout("created snapid=%lld\n", new_snapid);
+	if (ret < 0)
+		goto err_sizes;
+
+	new_snapc->seq = new_snapid; /* we're still pointing at the head */
+	header->snap_seq = new_snapid;
+	new_snapc->snaps[0] = new_snapid;
+
+	/* copy snap names */
+	if (header->snap_names)
+		memcpy(new_names + name_len + 1, header->snap_names,
+		       header->snap_names_len);
+
+	memcpy(new_names, snap_name, name_len + 1);
+	header->snap_names_len += name_len + 1;
+
+	/* copy snap image sizes */
+	if (header->snap_sizes)
+		memcpy(new_sizes, header->snap_sizes,
+		       header->total_snaps * sizeof(u64));
+	new_sizes[new_snapc->num_snaps - 1] = header->image_size;
+
+	header->total_snaps = new_snapc->num_snaps;
+
+	kfree(header->snapc);
+	header->snapc = new_snapc;
+	kfree(header->snap_names);
+	header->snap_names = new_names;
+	kfree(header->snap_sizes);
+	header->snap_sizes = new_sizes;
+
+	ret = 0;
+done:
+	up_write(&header->snap_rwsem);
+	return ret;
+err_sizes:
+	kfree(new_sizes);
+err_names:
+	kfree(new_names);
+err_snapc:
+	kfree(new_snapc);
+	up_write(&header->snap_rwsem);
+	return ret;
+}
+
+static int rbd_header_set_snap(struct rbd_device *dev,
+			       const char *snap_name,
+			       u64 *size)
+{
+	struct rbd_obj_header *header = &dev->header;
+	struct ceph_snap_context *snapc = header->snapc;
+	char *p;
+	int i;
+	int ret = -ENOENT;
+
+	down_write(&header->snap_rwsem);
+
+	if (!snap_name ||
+	    !*snap_name ||
+	    strcmp(snap_name, "-") == 0 ||
+	    strcmp(snap_name, RBD_SNAP_HEAD_NAME) == 0) {
+		if (header->total_snaps)
+			snapc->seq = header->snap_seq;
+		else
+			snapc->seq = 0;
+		dev->cur_snap = 0;
+		dev->read_only = 0;
+		if (size)
+			*size = header->image_size;
+	} else {
+		p = header->snap_names;
+		for (i = 0; i < header->total_snaps; i++, p += strlen(p) + 1) {
+			if (strcmp(snap_name, p) == 0)
+				break;
+		}
+		if (i == header->total_snaps)
+			goto done;
+
+		snapc->seq = snapc->snaps[i];
+		dev->cur_snap = header->total_snaps - i;
+		dev->read_only = 1;
+		if (size)
+			*size = header->snap_sizes[i];
+	}
+
+	ret = 0;
+done:
+	up_write(&header->snap_rwsem);
+	return ret;
+}
+
+static void rbd_header_free(struct rbd_obj_header *header)
+{
+	kfree(header->snapc);
+	kfree(header->snap_names);
+	kfree(header->snap_sizes);
+}
+
+/*
+ * get the actual striped segment name, offset and length
+ */
+static u64 rbd_get_segment(struct rbd_obj_header *header,
+			   const char *obj_name,
+			   u64 ofs, u64 len,
+			   char *seg_name, u64 *segofs)
+{
+	u64 seg = ofs >> header->obj_order;
+
+	if (seg_name)
+		snprintf(seg_name, RBD_MAX_SEG_NAME_SIZE,
+			 "%s.%012llx", obj_name, seg);
+
+	ofs = ofs & ((1 << header->obj_order) - 1);
+	len = min_t(u64, len, (1 << header->obj_order) - ofs);
+
+	if (segofs)
+		*segofs = ofs;
+
+	return len;
+}
+
+static void bio_chain_put(struct bio *chain)
+{
+	struct bio *tmp;
+
+	while (chain) {
+		tmp = chain;
+		chain = chain->bi_next;
+
+		bio_put(tmp);
+	}
+}
+
+/*
+ * zeros a bio chain, starting at specific offset
+ */
+static void zero_bio_chain(struct bio *chain, int start_ofs)
+{
+	struct bio_vec *bv;
+	unsigned long flags;
+	void *buf;
+	int i;
+	int pos = 0;
+
+	while (chain) {
+		bio_for_each_segment(bv, chain, i) {
+			if (pos + bv->bv_len > start_ofs) {
+				int remainder = max(start_ofs - pos, 0);
+				buf = bvec_kmap_irq(bv, &flags);
+				memset(buf + remainder, 0,
+				       bv->bv_len - remainder);
+				bvec_kunmap_irq(bv, &flags);
+			}
+			pos += bv->bv_len;
+		}
+
+		chain = chain->bi_next;
+	}
+}
+
+/*
+ * bio_chain_clone - clone a chain of bios up to a certain length.
+ * might return a bio_pair that will need to be released.
+ */
+static struct bio *bio_chain_clone(struct bio **old, struct bio **next,
+				   struct bio_pair **bp,
+				   int len, gfp_t gfpmask)
+{
+	struct bio *tmp, *old_chain = *old, *new_chain = NULL, *tail = NULL;
+	int total = 0;
+
+	if (*bp) {
+		bio_pair_release(*bp);
+		*bp = NULL;
+	}
+
+	while (old_chain && (total < len)) {
+		tmp = bio_kmalloc(gfpmask, old_chain->bi_max_vecs);
+		if (!tmp)
+			goto err_out;
+
+		if (total + old_chain->bi_size > len) {
+			struct bio_pair *bp;
+
+			/*
+			 * this split can only happen with a single paged bio,
+			 * split_bio will BUG_ON if this is not the case
+			 */
+			dout("bio_chain_clone split! total=%d remaining=%d"
+			     "bi_size=%d\n",
+			     (int)total, (int)len-total,
+			     (int)old_chain->bi_size);
+
+			/* split the bio. We'll release it either in the next
+			   call, or it will have to be released outside */
+			bp = bio_split(old_chain, (len - total) / 512ULL);
+			if (!bp)
+				goto err_out;
+
+			__bio_clone(tmp, &bp->bio1);
+
+			*next = &bp->bio2;
+		} else {
+			__bio_clone(tmp, old_chain);
+			*next = old_chain->bi_next;
+		}
+
+		tmp->bi_bdev = NULL;
+		gfpmask &= ~__GFP_WAIT;
+		tmp->bi_next = NULL;
+
+		if (!new_chain) {
+			new_chain = tail = tmp;
+		} else {
+			tail->bi_next = tmp;
+			tail = tmp;
+		}
+		old_chain = old_chain->bi_next;
+
+		total += tmp->bi_size;
+	}
+
+	BUG_ON(total < len);
+
+	if (tail)
+		tail->bi_next = NULL;
+
+	*old = old_chain;
+
+	return new_chain;
+
+err_out:
+	dout("bio_chain_clone with err\n");
+	bio_chain_put(new_chain);
+	return NULL;
+}
+
+/*
+ * Send ceph osd request
+ */
+static int rbd_do_request(struct request *rq,
+			  struct rbd_device *dev,
+			  struct ceph_snap_context *snapc,
+			  u64 snapid,
+			  const char *obj, u64 ofs, u64 len,
+			  struct bio *bio,
+			  struct page **pages,
+			  int num_pages,
+			  int opcode, int flags,
+			  int num_reply,
+			  void (*rbd_cb)(struct ceph_osd_request *req,
+					 struct ceph_msg *msg))
+{
+	struct ceph_osd_request *req;
+	struct ceph_file_layout *layout;
+	int ret;
+	u64 bno;
+	struct timespec mtime = CURRENT_TIME;
+	struct rbd_request *req_data;
+	struct ceph_osd_request_head *reqhead;
+	struct rbd_obj_header *header = &dev->header;
+
+	ret = -ENOMEM;
+	req_data = kzalloc(sizeof(*req_data), GFP_NOFS);
+	if (!req_data)
+		goto done;
+
+	dout("rbd_do_request len=%lld ofs=%lld\n", len, ofs);
+
+	down_read(&header->snap_rwsem);
+
+	req = ceph_osdc_alloc_request(&dev->client->osdc, flags,
+				      snapc, 0,
+				      false,
+				      GFP_NOFS, pages, bio);
+	if (IS_ERR(req)) {
+		up_read(&header->snap_rwsem);
+		ret = PTR_ERR(req);
+		goto done_pages;
+	}
+
+	req->r_callback = rbd_cb;
+
+	req_data->rq = rq;
+	req_data->bio = bio;
+	req_data->pages = pages;
+	req_data->len = len;
+
+	req->r_priv = req_data;
+
+	reqhead = req->r_request->front.iov_base;
+	reqhead->snapid = cpu_to_le64(CEPH_NOSNAP);
+
+	strncpy(req->r_oid, obj, sizeof(req->r_oid));
+	req->r_oid_len = strlen(req->r_oid);
+
+	layout = &req->r_file_layout;
+	memset(layout, 0, sizeof(*layout));
+	layout->fl_stripe_unit = RBD_STRIPE_UNIT;
+	layout->fl_stripe_count = 1;
+	layout->fl_object_size = RBD_STRIPE_UNIT;
+	layout->fl_pg_preferred = -1;
+	layout->fl_pg_pool = dev->poolid;
+	ceph_calc_raw_layout(&dev->client->osdc, layout, snapid,
+			     ofs, len, &bno, req);
+
+	ceph_osdc_build_request(req, ofs, &len, opcode,
+				snapc, 0,
+				0, 0,
+				&mtime,
+				req->r_oid, req->r_oid_len);
+	up_read(&header->snap_rwsem);
+
+	ret = ceph_osdc_start_request(&dev->client->osdc, req, false);
+	if (ret < 0)
+		goto done_err;
+
+	if (!rbd_cb) {
+		ret = ceph_osdc_wait_request(&dev->client->osdc, req);
+		ceph_osdc_put_request(req);
+	}
+	return ret;
+
+done_err:
+	bio_chain_put(req_data->bio);
+	ceph_osdc_put_request(req);
+done_pages:
+	kfree(req_data);
+done:
+	if (rq)
+		blk_end_request(rq, ret, len);
+	return ret;
+}
+
+/*
+ * Ceph osd op callback
+ */
+static void rbd_req_cb(struct ceph_osd_request *req, struct ceph_msg *msg)
+{
+	struct rbd_request *req_data = req->r_priv;
+	struct ceph_osd_reply_head *replyhead;
+	struct ceph_osd_op *op;
+	__s32 rc;
+	u64 bytes;
+	int read_op;
+
+	/* parse reply */
+	replyhead = msg->front.iov_base;
+	WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
+	op = (void *)(replyhead + 1);
+	rc = le32_to_cpu(replyhead->result);
+	bytes = le64_to_cpu(op->extent.length);
+
+	dout("rbd_req_cb bytes=%lld rc=%d\n", bytes, rc);
+
+	read_op = (le32_to_cpu(op->op) == CEPH_OSD_OP_READ);
+
+	if (rc == -ENOENT && read_op) {
+		zero_bio_chain(req_data->bio, 0);
+		rc = 0;
+	} else if (rc == 0 && read_op && bytes < req_data->len) {
+		zero_bio_chain(req_data->bio, bytes);
+		bytes = req_data->len;
+	}
+
+	blk_end_request(req_data->rq, rc, bytes);
+
+	if (req_data->bio)
+		bio_chain_put(req_data->bio);
+
+	ceph_osdc_put_request(req);
+	kfree(req_data);
+}
+
+/*
+ * Do a synchronous ceph osd operation
+ */
+static int rbd_req_sync_op(struct rbd_device *dev,
+			   struct ceph_snap_context *snapc,
+			   u64 snapid,
+			   int opcode, int flags,
+			   int num_reply,
+			   const char *obj,
+			   u64 ofs, u64 len,
+			   char *buf)
+{
+	int ret;
+	struct page **pages;
+	int num_pages;
+
+	num_pages = calc_pages_for(ofs , len);
+	pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
+	if (!pages)
+		return -ENOMEM;
+
+	if (flags & CEPH_OSD_FLAG_WRITE) {
+		ret = ceph_copy_to_page_vector(pages, buf, ofs, len);
+		if (ret < 0)
+			goto done;
+	}
+
+	ret = rbd_do_request(NULL, dev, snapc, snapid,
+			  obj, ofs, len, NULL,
+			  pages, num_pages,
+			  opcode,
+			  flags,
+			  2,
+			  NULL);
+	if (ret < 0)
+		goto done;
+
+	if (flags & CEPH_OSD_FLAG_READ)
+		ret = ceph_copy_from_page_vector(pages, buf, ofs, ret);
+
+done:
+	ceph_release_page_vector(pages, num_pages);
+	return ret;
+}
+
+/*
+ * Do an asynchronous ceph osd operation
+ */
+static int rbd_do_op(struct request *rq,
+		     struct rbd_device *rbd_dev ,
+		     struct ceph_snap_context *snapc,
+		     u64 snapid,
+		     int opcode, int flags, int num_reply,
+		     u64 ofs, u64 len,
+		     struct bio *bio)
+{
+	char *seg_name;
+	u64 seg_ofs;
+	u64 seg_len;
+	int ret;
+
+	seg_name = kmalloc(RBD_MAX_SEG_NAME_SIZE + 1, GFP_NOIO);
+	if (!seg_name)
+		return -ENOMEM;
+
+	seg_len = rbd_get_segment(&rbd_dev->header,
+				  rbd_dev->obj,
+				  ofs, len,
+				  seg_name, &seg_ofs);
+	if (seg_len < 0)
+		return seg_len;
+
+	/* we've taken care of segment sizes earlier when we
+	   cloned the bios. We should never have a segment
+	   truncated at this point */
+	BUG_ON(seg_len < len);
+
+	ret = rbd_do_request(rq, rbd_dev, snapc, snapid,
+			     seg_name, seg_ofs, seg_len,
+			     bio,
+			     NULL, 0,
+			     opcode,
+			     flags,
+			     num_reply,
+			     rbd_req_cb);
+	kfree(seg_name);
+	return ret;
+}
+
+/*
+ * Request async osd write
+ */
+static int rbd_req_write(struct request *rq,
+			 struct rbd_device *rbd_dev,
+			 struct ceph_snap_context *snapc,
+			 u64 ofs, u64 len,
+			 struct bio *bio)
+{
+	return rbd_do_op(rq, rbd_dev, snapc, CEPH_NOSNAP,
+			 CEPH_OSD_OP_WRITE,
+			 CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
+			 2,
+			 ofs, len, bio);
+}
+
+/*
+ * Request sync osd write
+ */
+static int rbd_req_sync_write(struct rbd_device *dev,
+			  struct ceph_snap_context *snapc,
+			  u64 snapid,
+			  const char *obj,
+			  u64 ofs, u64 len,
+			  char *buf)
+{
+	return rbd_req_sync_op(dev, snapc, snapid,
+			       CEPH_OSD_OP_WRITE,
+			       CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
+			       2, obj, ofs, len, buf);
+}
+
+/*
+ * Request async osd read
+ */
+static int rbd_req_read(struct request *rq,
+			 struct rbd_device *rbd_dev,
+			 u64 snapid,
+			 u64 ofs, u64 len,
+			 struct bio *bio)
+{
+	return rbd_do_op(rq, rbd_dev, NULL,
+			 (snapid ? snapid : CEPH_NOSNAP),
+			 CEPH_OSD_OP_READ,
+			 CEPH_OSD_FLAG_READ,
+			 2,
+			 ofs, len, bio);
+}
+
+/*
+ * Request sync osd read
+ */
+static int rbd_req_sync_read(struct rbd_device *dev,
+			  struct ceph_snap_context *snapc,
+			  u64 snapid,
+			  const char *obj,
+			  u64 ofs, u64 len,
+			  char *buf)
+{
+	return rbd_req_sync_op(dev, NULL,
+			       (snapid ? snapid : CEPH_NOSNAP),
+			       CEPH_OSD_OP_READ,
+			       CEPH_OSD_FLAG_READ,
+			       1, obj, ofs, len, buf);
+}
+
+/*
+ * block device queue callback
+ */
+static void rbd_rq_fn(struct request_queue *q)
+{
+	struct rbd_device *rbd_dev = q->queuedata;
+	struct request *rq;
+	struct bio_pair *bp = NULL;
+
+	rq = blk_fetch_request(q);
+
+	while (1) {
+		struct bio *bio;
+		struct bio *rq_bio, *next_bio = NULL;
+		bool do_write;
+		int size, op_size = 0;
+		u64 ofs;
+
+		/* peek at request from block layer */
+		if (!rq)
+			break;
+
+		dout("fetched request\n");
+
+		/* filter out block requests we don't understand */
+		if (!blk_fs_request(rq) && !blk_barrier_rq(rq)) {
+			__blk_end_request_all(rq, 0);
+			goto next;
+		}
+
+		/* deduce our operation (read, write) */
+		do_write = (rq_data_dir(rq) == WRITE);
+
+		size = blk_rq_bytes(rq);
+		ofs = blk_rq_pos(rq) * 512ULL;
+		rq_bio = rq->bio;
+		if (do_write && rbd_dev->read_only) {
+			__blk_end_request_all(rq, -EROFS);
+			goto next;
+		}
+
+		spin_unlock_irq(q->queue_lock);
+
+		dout("%s 0x%x bytes at 0x%llx\n",
+		     do_write ? "write" : "read",
+		     size, blk_rq_pos(rq) * 512ULL);
+
+		do {
+			/* a bio clone to be passed down to OSD req */
+			dout("rq->bio->bi_vcnt=%d\n", rq->bio->bi_vcnt);
+			op_size = rbd_get_segment(&rbd_dev->header,
+						  rbd_dev->obj,
+						  ofs, size,
+						  NULL, NULL);
+			bio = bio_chain_clone(&rq_bio, &next_bio, &bp,
+					      op_size, GFP_ATOMIC);
+			if (!bio) {
+				spin_lock_irq(q->queue_lock);
+				__blk_end_request_all(rq, -ENOMEM);
+				goto next;
+			}
+
+			/* init OSD command: write or read */
+			if (do_write)
+				rbd_req_write(rq, rbd_dev,
+					      rbd_dev->header.snapc,
+					      ofs,
+					      op_size, bio);
+			else
+				rbd_req_read(rq, rbd_dev,
+					     cur_snap_id(rbd_dev),
+					     ofs,
+					     op_size, bio);
+
+			size -= op_size;
+			ofs += op_size;
+
+			rq_bio = next_bio;
+		} while (size > 0);
+
+		if (bp)
+			bio_pair_release(bp);
+
+		spin_lock_irq(q->queue_lock);
+next:
+		rq = blk_fetch_request(q);
+	}
+}
+
+/*
+ * a queue callback. Makes sure that we don't create a bio that spans across
+ * multiple osd objects. One exception would be with a single page bios,
+ * which we handle later at bio_chain_clone
+ */
+static int rbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bmd,
+			  struct bio_vec *bvec)
+{
+	sector_t sector = bmd->bi_sector + get_start_sect(bmd->bi_bdev);
+	unsigned int chunk_sectors = (RBD_STRIPE_UNIT >> 9);
+	unsigned int bio_sectors = bmd->bi_size >> 9;
+	int max;
+
+	max =  (chunk_sectors - ((sector & (chunk_sectors - 1))
+				 + bio_sectors)) << 9;
+	if (max < 0)
+		max = 0; /* bio_add cannot handle a negative return */
+	if (max <= bvec->bv_len && bio_sectors == 0)
+		return bvec->bv_len;
+	return max;
+}
+
+static void rbd_free_disk(struct rbd_device *rbd_dev)
+{
+	struct gendisk *disk = rbd_dev->disk;
+
+	if (!disk)
+		return;
+
+	rbd_header_free(&rbd_dev->header);
+
+	if (disk->flags & GENHD_FL_UP)
+		del_gendisk(disk);
+	if (disk->queue)
+		blk_cleanup_queue(disk->queue);
+	put_disk(disk);
+}
+
+static char *rbd_alloc_md_name(struct rbd_device *rbd_dev, gfp_t gfp_flags)
+{
+	char *obj_md_name = kmalloc(strlen(rbd_dev->obj) + sizeof(RBD_SUFFIX),
+			      gfp_flags);
+	if (!obj_md_name)
+		return NULL;
+	sprintf(obj_md_name, "%s%s", rbd_dev->obj, RBD_SUFFIX);
+
+	return obj_md_name;
+}
+
+static int rbd_read_header(struct rbd_device *rbd_dev,
+			   struct rbd_obj_header *header)
+{
+	ssize_t rc;
+	char *obj_md_name;
+	struct rbd_obj_header_ondisk *dh;
+	int snap_count = 0;
+	u64 snap_names_len = 0;
+
+	obj_md_name = rbd_alloc_md_name(rbd_dev, GFP_KERNEL);
+	if (!obj_md_name)
+		return -ENOMEM;
+
+	while (1) {
+		int len = sizeof(*dh) +
+			  snap_count * sizeof(struct rbd_obj_snap_ondisk) +
+			  snap_names_len;
+
+		rc = -ENOMEM;
+		dh = kmalloc(len, GFP_KERNEL);
+		if (!dh)
+			goto out_obj_md;
+
+		rc = rbd_req_sync_read(rbd_dev,
+				       NULL, CEPH_NOSNAP,
+				       obj_md_name,
+				       0, len,
+				       (char *)dh);
+		if (rc < 0)
+			goto out_dh;
+
+		rc = rbd_header_from_disk(header, dh, snap_count, GFP_KERNEL);
+		if (rc < 0)
+			goto out_dh;
+
+		if (snap_count != header->total_snaps) {
+			snap_count = header->total_snaps;
+			snap_names_len = header->snap_names_len;
+			rbd_header_free(header);
+			kfree(dh);
+			continue;
+		}
+		break;
+	}
+
+out_dh:
+	kfree(dh);
+out_obj_md:
+	kfree(obj_md_name);
+	return rc;
+}
+
+/*
+ * only read the first part of the ondisk header, without the snaps info
+ */
+static int rbd_read_ondisk_header_nosnap(struct rbd_device *rbd_dev,
+				  struct rbd_obj_header *header,
+				  struct rbd_obj_header_ondisk *dh)
+{
+	ssize_t rc;
+	char *obj_md_name;
+	int len;
+
+	obj_md_name = rbd_alloc_md_name(rbd_dev, GFP_KERNEL);
+	if (!obj_md_name)
+		return -ENOMEM;
+
+	len = sizeof(struct rbd_obj_header_ondisk);
+
+	rc = rbd_req_sync_read(rbd_dev,
+			       NULL, CEPH_NOSNAP,
+			       obj_md_name,
+			       0, len,
+			       (char *)dh);
+	if (rc > 0 && rc < len)
+		rc = -EIO;
+
+	kfree(obj_md_name);
+	return rc;
+}
+
+static int rbd_write_header(struct rbd_device *rbd_dev,
+			    struct rbd_obj_header_ondisk *dh,
+			    struct rbd_obj_header *header)
+{
+	ssize_t rc;
+	char *obj_md_name;
+	int snap_count = header->total_snaps;
+	u64 snap_names_len  = header->snap_names_len;
+	int len;
+
+	obj_md_name = rbd_alloc_md_name(rbd_dev, GFP_KERNEL);
+	if (!obj_md_name)
+		return -ENOMEM;
+
+	len = sizeof(*dh) +
+	      snap_count * sizeof(struct rbd_obj_snap_ondisk) +
+	      snap_names_len;
+
+	rc = rbd_req_sync_write(rbd_dev,
+			       NULL, CEPH_NOSNAP,
+			       obj_md_name,
+			       0, len,
+			       (char *)dh);
+	kfree(obj_md_name);
+	return rc;
+}
+
+static int rbd_update_snaps(struct rbd_device *rbd_dev)
+{
+	int ret;
+	struct rbd_obj_header h;
+
+	ret = rbd_read_header(rbd_dev, &h);
+	if (ret < 0)
+		return ret;
+
+	down_write(&rbd_dev->header.snap_rwsem);
+
+	kfree(rbd_dev->header.snapc);
+	kfree(rbd_dev->header.snap_names);
+	kfree(rbd_dev->header.snap_sizes);
+
+	rbd_dev->header.total_snaps = h.total_snaps;
+	rbd_dev->header.snapc = h.snapc;
+	rbd_dev->header.snap_names = h.snap_names;
+	rbd_dev->header.snap_sizes = h.snap_sizes;
+
+	up_write(&rbd_dev->header.snap_rwsem);
+
+	return 0;
+}
+
+static int rbd_init_disk(struct rbd_device *rbd_dev)
+{
+	struct gendisk *disk;
+	struct request_queue *q;
+	int rc;
+	u64 total_size;
+	const char *snap = NULL;
+
+	/* contact OSD, request size info about the object being mapped */
+	rc = rbd_read_header(rbd_dev, &rbd_dev->header);
+	if (rc)
+		return rc;
+
+	if (rbd_dev->client->mount_args)
+		snap = rbd_dev->client->mount_args->snap;
+	rc = rbd_header_set_snap(rbd_dev, snap, &total_size);
+	if (rc)
+		return rc;
+
+	/* create gendisk info */
+	rc = -ENOMEM;
+	disk = alloc_disk(RBD_MINORS_PER_MAJOR);
+	if (!disk)
+		goto out;
+
+	sprintf(disk->disk_name, DRV_NAME "%d", rbd_dev->id);
+	disk->major = rbd_dev->major;
+	disk->first_minor = 0;
+	disk->fops = &rbd_bd_ops;
+	disk->private_data = rbd_dev;
+
+	/* init rq */
+	rc = -ENOMEM;
+	q = blk_init_queue(rbd_rq_fn, &rbd_dev->lock);
+	if (!q)
+		goto out_disk;
+	blk_queue_merge_bvec(q, rbd_merge_bvec);
+	disk->queue = q;
+
+	q->queuedata = rbd_dev;
+
+	rbd_dev->disk = disk;
+	rbd_dev->q = q;
+
+	/* finally, announce the disk to the world */
+	set_capacity(disk, total_size / 512ULL);
+	add_disk(disk);
+
+	pr_info("%s: added with size 0x%llx\n",
+		disk->disk_name, (unsigned long long)total_size);
+	return 0;
+
+out_disk:
+	put_disk(disk);
+out:
+	return rc;
+}
+
+/********************************************************************
+ * /sys/class/rbd/
+ *                   add	map rados objects to blkdev
+ *                   remove	unmap rados objects
+ *                   list	show mappings
+ *******************************************************************/
+
+static void class_rbd_release(struct class *cls)
+{
+	kfree(cls);
+}
+
+static ssize_t class_rbd_list(struct class *c,
+			      struct class_attribute *attr,
+			      char *data)
+{
+	int n = 0;
+	struct list_head *tmp;
+
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+
+	list_for_each(tmp, &rbddev_list) {
+		struct rbd_device *rbd_dev;
+
+		rbd_dev = list_entry(tmp, struct rbd_device, node);
+		n += sprintf(data+n, "%d %d client%lld %s %s\n",
+			     rbd_dev->id,
+			     rbd_dev->major,
+			     ceph_client_id(rbd_dev->client),
+			     rbd_dev->pool_name,
+			     rbd_dev->obj);
+	}
+
+	mutex_unlock(&ctl_mutex);
+	return n;
+}
+
+static ssize_t class_rbd_add(struct class *c,
+			     struct class_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct rbd_device *rbd_dev;
+	ssize_t rc = -ENOMEM;
+	int irc, new_id = 0;
+	struct list_head *tmp;
+	char *mon_dev_name;
+	char *opt;
+
+	if (!try_module_get(THIS_MODULE))
+		return -ENODEV;
+
+	mon_dev_name = kmalloc(RBD_MAX_OPT_LEN, GFP_KERNEL);
+	if (!mon_dev_name)
+		goto err_out_mod;
+
+	opt = kmalloc(RBD_MAX_OPT_LEN, GFP_KERNEL);
+	if (!opt)
+		goto err_mon_dev;
+
+	/* new rbd_device object */
+	rbd_dev = kzalloc(sizeof(*rbd_dev), GFP_KERNEL);
+	if (!rbd_dev)
+		goto err_out_opt;
+
+	/* static rbd_device initialization */
+	spin_lock_init(&rbd_dev->lock);
+	INIT_LIST_HEAD(&rbd_dev->node);
+
+	/* generate unique id: find highest unique id, add one */
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+
+	list_for_each(tmp, &rbddev_list) {
+		struct rbd_device *rbd_dev;
+
+		rbd_dev = list_entry(tmp, struct rbd_device, node);
+		if (rbd_dev->id >= new_id)
+			new_id = rbd_dev->id + 1;
+	}
+
+	rbd_dev->id = new_id;
+
+	/* add to global list */
+	list_add_tail(&rbd_dev->node, &rbddev_list);
+
+	/* parse add command */
+	if (sscanf(buf, "%" __stringify(RBD_MAX_OPT_LEN) "s "
+		   "%" __stringify(RBD_MAX_OPT_LEN) "s "
+		   "%" __stringify(RBD_MAX_POOL_NAME_SIZE) "s "
+		   "%" __stringify(RBD_MAX_OBJ_NAME_SIZE) "s",
+		   mon_dev_name, opt, rbd_dev->pool_name,
+		   rbd_dev->obj) != 4) {
+		rc = -EINVAL;
+		goto err_out_slot;
+	}
+
+	rbd_dev->obj_len = strlen(rbd_dev->obj);
+
+	/* initialize rest of new object */
+	snprintf(rbd_dev->name, DEV_NAME_LEN, DRV_NAME "%d", rbd_dev->id);
+	rc = rbd_get_client(rbd_dev, mon_dev_name, opt);
+	if (rc < 0)
+		goto err_out_slot;
+
+	mutex_unlock(&ctl_mutex);
+	/* register our block device */
+	irc = register_blkdev(0, rbd_dev->name);
+	if (irc < 0) {
+		rc = irc;
+		goto err_out_client;
+	}
+	rbd_dev->major = irc;
+
+	/* set up and announce blkdev mapping */
+	rc = rbd_init_disk(rbd_dev);
+	if (rc)
+		goto err_out_blkdev;
+
+	return count;
+
+err_out_blkdev:
+	unregister_blkdev(rbd_dev->major, rbd_dev->name);
+err_out_client:
+	rbd_put_client(rbd_dev);
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+err_out_slot:
+	list_del_init(&rbd_dev->node);
+	mutex_unlock(&ctl_mutex);
+
+	kfree(rbd_dev);
+err_out_opt:
+	kfree(opt);
+err_mon_dev:
+	kfree(mon_dev_name);
+err_out_mod:
+	dout("Error adding device %s\n", buf);
+	module_put(THIS_MODULE);
+	return rc;
+}
+
+static struct rbd_device *__rbd_get_dev(unsigned long id)
+{
+	struct list_head *tmp;
+	struct rbd_device *rbd_dev = NULL;
+
+	list_for_each(tmp, &rbddev_list) {
+		rbd_dev = list_entry(tmp, struct rbd_device, node);
+		if (rbd_dev->id == id)
+			break;
+
+		rbd_dev = NULL;
+	}
+
+	return rbd_dev;
+}
+
+static ssize_t class_rbd_remove(struct class *c,
+				struct class_attribute *attr,
+				const char *buf,
+				size_t count)
+{
+	struct rbd_device *rbd_dev = NULL;
+	int target_id, rc;
+	unsigned long ul;
+
+	rc = strict_strtoul(buf, 10, &ul);
+	if (rc)
+		return rc;
+
+	/* convert to int; abort if we lost anything in the conversion */
+	target_id = (int) ul;
+	if (target_id != ul)
+		return -EINVAL;
+
+	/* remove object from list immediately */
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+
+	rbd_dev = __rbd_get_dev(target_id);
+	if (rbd_dev)
+		list_del_init(&rbd_dev->node);
+
+	mutex_unlock(&ctl_mutex);
+
+	if (!rbd_dev)
+		return -ENOENT;
+
+	rbd_put_client(rbd_dev);
+
+	/* clean up and free blkdev and associated OSD connection */
+	rbd_free_disk(rbd_dev);
+	unregister_blkdev(rbd_dev->major, rbd_dev->name);
+	kfree(rbd_dev);
+
+	/* release module ref */
+	module_put(THIS_MODULE);
+
+	return count;
+}
+
+static void get_size_and_suffix(u64 orig_size, u64 *size, char *suffix)
+{
+	if (orig_size >= 1024*1024*1024) {
+		*size = orig_size / (1024*1024*1024);
+		*suffix = 'G';
+	} else if (orig_size >= 1024*1024) {
+		*size = orig_size / (1024*1024);
+		*suffix = 'M';
+	} else if (orig_size >= 1024) {
+		*size = orig_size / 1024;
+		*suffix = 'K';
+	} else {
+		*size = orig_size;
+		*suffix = ' ';
+	}
+}
+
+static ssize_t class_rbd_snaps_list(struct class *c,
+			      struct class_attribute *attr,
+			      char *data)
+{
+	struct rbd_device *rbd_dev = NULL;
+	struct list_head *tmp;
+	struct rbd_obj_header *header;
+	char size_suffix;
+	u64 size;
+	int i, n = 0, max = PAGE_SIZE;
+	int ret;
+
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+
+	list_for_each(tmp, &rbddev_list) {
+		char *names, *p;
+		struct ceph_snap_context *snapc;
+
+		rbd_dev = list_entry(tmp, struct rbd_device, node);
+		header = &rbd_dev->header;
+		names = header->snap_names;
+		snapc = header->snapc;
+		n += snprintf(data + n, max - n,
+			      "snapshots for device id %d:\n",
+			      rbd_dev->id);
+		if (n == max)
+			break;
+
+		down_read(&header->snap_rwsem);
+
+		get_size_and_suffix(header->image_size, &size,
+				    &size_suffix);
+		n += snprintf(data + n, max - n, "%s\t%lld%c%s\n",
+				      RBD_SNAP_HEAD_NAME,
+				      size, size_suffix,
+				      (!rbd_dev->cur_snap ?
+				       " (*)" : ""));
+		if (n == max)
+			break;
+
+		p = names;
+		for (i = 0; i < header->total_snaps; i++, p += strlen(p) + 1) {
+			get_size_and_suffix(header->snap_sizes[i], &size,
+					    &size_suffix);
+			n += snprintf(data + n, max - n, "%s\t%lld%c%s\n",
+			      p, size, size_suffix,
+			      (rbd_dev->cur_snap &&
+			       (snap_index(header, i) == rbd_dev->cur_snap) ?
+			       " (*)" : ""));
+			if (n == max)
+				break;
+		}
+
+		up_read(&header->snap_rwsem);
+	}
+
+
+	ret = n;
+	mutex_unlock(&ctl_mutex);
+	return ret;
+}
+
+static ssize_t class_rbd_snaps_refresh(struct class *c,
+				struct class_attribute *attr,
+				const char *buf,
+				size_t count)
+{
+	struct rbd_device *rbd_dev = NULL;
+	int target_id, rc;
+	unsigned long ul;
+	int ret = count;
+
+	rc = strict_strtoul(buf, 10, &ul);
+	if (rc)
+		return rc;
+
+	/* convert to int; abort if we lost anything in the conversion */
+	target_id = (int) ul;
+	if (target_id != ul)
+		return -EINVAL;
+
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+
+	rbd_dev = __rbd_get_dev(target_id);
+	if (!rbd_dev) {
+		ret = -ENOENT;
+		goto done;
+	}
+
+	rc = rbd_update_snaps(rbd_dev);
+	if (rc < 0)
+		ret = rc;
+
+done:
+	mutex_unlock(&ctl_mutex);
+	return ret;
+}
+
+static ssize_t class_rbd_snaps_op(struct class *c,
+				struct class_attribute *attr,
+				const char *buf,
+				size_t count,
+				int snaps_op)
+{
+	struct rbd_device *rbd_dev = NULL;
+	int target_id, ret;
+	char *name;
+	struct rbd_obj_header_ondisk old_ondisk, *new_ondisk;
+
+	name = kmalloc(RBD_MAX_SNAP_NAME_LEN + 1, GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+
+	/* parse snaps add command */
+	if (sscanf(buf, "%d "
+		   "%" __stringify(RBD_MAX_SNAP_NAME_LEN) "s",
+		   &target_id,
+		   name) != 2) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+
+	rbd_dev = __rbd_get_dev(target_id);
+	if (!rbd_dev) {
+		ret = -ENOENT;
+		goto done_unlock;
+	}
+
+	ret = rbd_read_ondisk_header_nosnap(rbd_dev,
+					    &rbd_dev->header,
+					    &old_ondisk);
+	if (ret < 0)
+		goto done_unlock;
+
+	switch (snaps_op) {
+	case RBD_SNAP_OP_CREATE:
+		ret = rbd_header_add_snap(rbd_dev,
+					  name, GFP_KERNEL);
+		break;
+	case RBD_SNAP_OP_SET:
+		ret = rbd_header_set_snap(rbd_dev, name, NULL);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	if (ret < 0)
+		goto done_unlock;
+
+	ret = rbd_header_to_disk(&new_ondisk, &old_ondisk,
+			      &rbd_dev->header, GFP_KERNEL);
+	if (ret < 0)
+		goto done_unlock;
+
+	ret = rbd_write_header(rbd_dev, new_ondisk, &rbd_dev->header);
+	if (ret < 0)
+		goto done_unlock;
+
+	ret = count;
+done_unlock:
+	mutex_unlock(&ctl_mutex);
+done:
+	kfree(name);
+	return ret;
+}
+
+static ssize_t class_rbd_snap_create(struct class *c,
+				     struct class_attribute *attr,
+				     const char *buf,
+				     size_t count)
+{
+	return class_rbd_snaps_op(c, attr, buf, count,
+				  RBD_SNAP_OP_CREATE);
+}
+
+static struct class_attribute class_rbd_attrs[] = {
+	__ATTR(add,		0200, NULL, class_rbd_add),
+	__ATTR(remove,		0200, NULL, class_rbd_remove),
+	__ATTR(list,		0444, class_rbd_list, NULL),
+	__ATTR(snaps_refresh,	0200, NULL, class_rbd_snaps_refresh),
+	__ATTR(snap_create,	0200, NULL, class_rbd_snap_create),
+	__ATTR(snaps_list,	0444, class_rbd_snaps_list, NULL),
+	__ATTR_NULL
+};
+
+/*
+ * create control files in sysfs
+ * /sys/class/rbd/...
+ */
+static int rbd_sysfs_init(void)
+{
+	int ret = -ENOMEM;
+
+	class_rbd = kzalloc(sizeof(*class_rbd), GFP_KERNEL);
+	if (!class_rbd)
+		goto out;
+
+	class_rbd->name = DRV_NAME;
+	class_rbd->owner = THIS_MODULE;
+	class_rbd->class_release = class_rbd_release;
+	class_rbd->class_attrs = class_rbd_attrs;
+
+	ret = class_register(class_rbd);
+	if (ret)
+		goto out_class;
+	return 0;
+
+out_class:
+	kfree(class_rbd);
+	class_rbd = NULL;
+	pr_err(DRV_NAME ": failed to create class rbd\n");
+out:
+	return ret;
+}
+
+static void rbd_sysfs_cleanup(void)
+{
+	if (class_rbd)
+		class_destroy(class_rbd);
+	class_rbd = NULL;
+}
+
+int __init rbd_init(void)
+{
+	int rc;
+
+	rc = rbd_sysfs_init();
+	if (rc)
+		return rc;
+	spin_lock_init(&node_lock);
+	pr_info("loaded " DRV_NAME_LONG);
+	return 0;
+}
+
+void __exit rbd_exit(void)
+{
+	rbd_sysfs_cleanup();
+}
diff --git a/fs/ceph/rbd.h b/fs/ceph/rbd.h
new file mode 100644
index 000000000000..68e0a5c69dc8
--- /dev/null
+++ b/fs/ceph/rbd.h
@@ -0,0 +1,8 @@
+#ifndef _FS_CEPH_RBD
+#define _FS_CEPH_RBD
+
+extern void rbd_set_osdc(struct ceph_osd_client *o);
+extern int __init rbd_init(void);
+extern void __exit rbd_exit(void);
+
+#endif
diff --git a/fs/ceph/rbd_types.h b/fs/ceph/rbd_types.h
new file mode 100644
index 000000000000..b73ac12ad0d6
--- /dev/null
+++ b/fs/ceph/rbd_types.h
@@ -0,0 +1,48 @@
+#ifndef _FS_CEPH_RBD
+#define _FS_CEPH_RBD
+
+#include <linux/types.h>
+
+/*
+ * rbd image 'foo' consists of objects
+ *   foo.rbd      - image metadata
+ *   foo.00000000 
+ *   foo.00000001
+ *   ...          - data
+ */
+
+#define RBD_SUFFIX	 	".rbd"
+#define RBD_DIRECTORY           "rbd_directory"
+
+#define RBD_DEFAULT_OBJ_ORDER	22   /* 4MB */
+
+#define RBD_MAX_OBJ_NAME_SIZE	96
+#define RBD_MAX_SEG_NAME_SIZE	128
+
+#define RBD_COMP_NONE		0
+#define RBD_CRYPT_NONE		0
+
+static const char rbd_text[] = "<<< Rados Block Device Image >>>\n";
+static const char rbd_signature[] = "RBD";
+static const char rbd_version[] = "001.002";
+
+struct rbd_obj_snap_ondisk {
+	__le64 id;
+	__le64 image_size;
+} __attribute__((packed));
+
+struct rbd_obj_header_ondisk {
+	char text[64];
+	char signature[4];
+	char version[8];
+	__le64 image_size;
+	__u8 obj_order;
+	__u8 crypt_type;
+	__u8 comp_type;
+	__le64 snap_seq;
+	__le32 snap_count;
+	__le64 snap_names_len;
+	struct rbd_obj_snap_ondisk snaps[0];
+} __attribute__((packed));
+
+#endif
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 4e0bee240b9d..c14d2623c9b5 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -18,6 +18,7 @@
 #include "super.h"
 #include "mon_client.h"
 #include "auth.h"
+#include "rbd.h"
 
 /*
  * Ceph superblock operations
@@ -342,6 +343,7 @@ enum {
 	Opt_snapdirname,
 	Opt_name,
 	Opt_secret,
+	Opt_snap,
 	Opt_last_string,
 	/* string args above */
 	Opt_ip,
@@ -374,6 +376,7 @@ static match_table_t arg_tokens = {
 	{Opt_snapdirname, "snapdirname=%s"},
 	{Opt_name, "name=%s"},
 	{Opt_secret, "secret=%s"},
+	{Opt_snap, "snap=%s"},
 	/* string args above */
 	{Opt_ip, "ip=%s"},
 	{Opt_noshare, "noshare"},
@@ -387,14 +390,15 @@ static match_table_t arg_tokens = {
 };
 
 
-static struct ceph_mount_args *parse_mount_args(int flags, char *options,
-						const char *dev_name,
-						const char **path)
+struct ceph_mount_args *parse_mount_args(int flags, char *options,
+					 const char *dev_name,
+					 const char **path)
 {
 	struct ceph_mount_args *args;
 	const char *c;
 	int err = -ENOMEM;
 	substring_t argstr[MAX_OPT_ARGS];
+	const char *end_path;
 
 	args = kzalloc(sizeof(*args), GFP_KERNEL);
 	if (!args)
@@ -426,23 +430,29 @@ static struct ceph_mount_args *parse_mount_args(int flags, char *options,
 	err = -EINVAL;
 	if (!dev_name)
 		goto out;
-	*path = strstr(dev_name, ":/");
-	if (*path == NULL) {
-		pr_err("device name is missing path (no :/ in %s)\n",
-		       dev_name);
-		goto out;
+
+	if (path) {
+		*path = strstr(dev_name, ":/");
+		if (*path == NULL) {
+			pr_err("device name is missing path (no :/ in %s)\n",
+			       dev_name);
+			goto out;
+		}
+		end_path = *path;
+
+		/* path on server */
+		*path += 2;
+		dout("server path '%s'\n", *path);
+	} else {
+		end_path = dev_name + strlen(dev_name);
 	}
 
 	/* get mon ip(s) */
-	err = ceph_parse_ips(dev_name, *path, args->mon_addr,
+	err = ceph_parse_ips(dev_name, end_path, args->mon_addr,
 			     CEPH_MAX_MON, &args->num_mon);
 	if (err < 0)
 		goto out;
 
-	/* path on server */
-	*path += 2;
-	dout("server path '%s'\n", *path);
-
 	/* parse mount options */
 	while ((c = strsep(&options, ",")) != NULL) {
 		int token, intval, ret;
@@ -501,6 +511,11 @@ static struct ceph_mount_args *parse_mount_args(int flags, char *options,
 						argstr[0].to-argstr[0].from,
 						GFP_KERNEL);
 			break;
+		case Opt_snap:
+			args->snap = kstrndup(argstr[0].from,
+					      argstr[0].to-argstr[0].from,
+					      GFP_KERNEL);
+			break;
 
 			/* misc */
 		case Opt_wsize:
@@ -569,22 +584,70 @@ out:
 	return ERR_PTR(err);
 }
 
-static void destroy_mount_args(struct ceph_mount_args *args)
+void ceph_destroy_mount_args(struct ceph_mount_args *args)
 {
 	dout("destroy_mount_args %p\n", args);
 	kfree(args->snapdir_name);
-	args->snapdir_name = NULL;
 	kfree(args->name);
-	args->name = NULL;
 	kfree(args->secret);
-	args->secret = NULL;
+	kfree(args->snap);
 	kfree(args);
 }
 
+static int strcmp_null(const char *s1, const char *s2)
+{
+	if (!s1 && !s2)
+		return 0;
+	if (s1 && !s2)
+		return -1;
+	if (!s1 && s2)
+		return 1;
+	return strcmp(s1, s2);
+}
+
+int ceph_compare_mount_args(struct ceph_mount_args *new_args,
+			    struct ceph_client *client)
+{
+	struct ceph_mount_args *args1 = new_args;
+	struct ceph_mount_args *args2 = client->mount_args;
+	int ofs = offsetof(struct ceph_mount_args, mon_addr);
+	int i;
+	int ret;
+
+	ret = memcmp(args1, args2, ofs);
+	if (ret)
+		return ret;
+
+	ret = strcmp_null(args1->snapdir_name, args2->snapdir_name);
+	if (ret)
+		return ret;
+
+	ret = strcmp_null(args1->name, args2->name);
+	if (ret)
+		return ret;
+
+	ret = strcmp_null(args1->secret, args2->secret);
+	if (ret)
+		return ret;
+
+	ret = strcmp_null(args1->snap, args2->snap);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < args1->num_mon; i++) {
+		if (ceph_monmap_contains(client->monc.monmap,
+				 &args1->mon_addr[i]))
+			return 0;
+	}
+
+	return -1;
+}
+
 /*
  * create a fresh client instance
  */
-static struct ceph_client *ceph_create_client(struct ceph_mount_args *args)
+struct ceph_client *ceph_create_client(struct ceph_mount_args *args,
+				       int need_mdsc)
 {
 	struct ceph_client *client;
 	int err = -ENOMEM;
@@ -639,9 +702,13 @@ static struct ceph_client *ceph_create_client(struct ceph_mount_args *args)
 	err = ceph_osdc_init(&client->osdc, client);
 	if (err < 0)
 		goto fail_monc;
-	err = ceph_mdsc_init(&client->mdsc, client);
-	if (err < 0)
-		goto fail_osdc;
+	if (need_mdsc) {
+		err = ceph_mdsc_init(&client->mdsc, client);
+		if (err < 0)
+			goto fail_osdc;
+		client->have_mdsc = 1;
+	}
+
 	return client;
 
 fail_osdc:
@@ -663,7 +730,12 @@ fail:
 	return ERR_PTR(err);
 }
 
-static void ceph_destroy_client(struct ceph_client *client)
+u64 ceph_client_id(struct ceph_client *client)
+{
+	return client->monc.auth->global_id;
+}
+
+void ceph_destroy_client(struct ceph_client *client)
 {
 	dout("destroy_client %p\n", client);
 
@@ -693,7 +765,7 @@ static void ceph_destroy_client(struct ceph_client *client)
 		ceph_messenger_destroy(client->msgr);
 	mempool_destroy(client->wb_pagevec_pool);
 
-	destroy_mount_args(client->mount_args);
+	ceph_destroy_mount_args(client->mount_args);
 
 	kfree(client);
 	dout("destroy_client %p done\n", client);
@@ -712,7 +784,7 @@ int ceph_check_fsid(struct ceph_client *client, struct ceph_fsid *fsid)
 		}
 	} else {
 		pr_info("client%lld fsid " FSID_FORMAT "\n",
-			client->monc.auth->global_id, PR_FSID(fsid));
+			ceph_client_id(client), PR_FSID(fsid));
 		memcpy(&client->fsid, fsid, sizeof(*fsid));
 		ceph_debugfs_client_init(client);
 		client->have_fsid = true;
@@ -774,17 +846,12 @@ static struct dentry *open_root_dentry(struct ceph_client *client,
 /*
  * mount: join the ceph cluster, and open root directory.
  */
-static int ceph_mount(struct ceph_client *client, struct vfsmount *mnt,
-		      const char *path)
+static int __ceph_open_session(struct ceph_client *client,
+			       unsigned long started)
 {
 	struct ceph_entity_addr *myaddr = NULL;
 	int err;
 	unsigned long timeout = client->mount_args->mount_timeout * HZ;
-	unsigned long started = jiffies;  /* note the start time */
-	struct dentry *root;
-
-	dout("mount start\n");
-	mutex_lock(&client->mount_mutex);
 
 	/* initialize the messenger */
 	if (client->msgr == NULL) {
@@ -792,9 +859,8 @@ static int ceph_mount(struct ceph_client *client, struct vfsmount *mnt,
 			myaddr = &client->mount_args->my_addr;
 		client->msgr = ceph_messenger_create(myaddr);
 		if (IS_ERR(client->msgr)) {
-			err = PTR_ERR(client->msgr);
 			client->msgr = NULL;
-			goto out;
+			return PTR_ERR(client->msgr);
 		}
 		client->msgr->nocrc = ceph_test_opt(client, NOCRC);
 	}
@@ -802,26 +868,58 @@ static int ceph_mount(struct ceph_client *client, struct vfsmount *mnt,
 	/* open session, and wait for mon, mds, and osd maps */
 	err = ceph_monc_open_session(&client->monc);
 	if (err < 0)
-		goto out;
+		return err;
 
 	while (!have_mon_and_osd_map(client)) {
 		err = -EIO;
 		if (timeout && time_after_eq(jiffies, started + timeout))
-			goto out;
+			return err;
 
 		/* wait */
 		dout("mount waiting for mon_map\n");
 		err = wait_event_interruptible_timeout(client->auth_wq,
-		       have_mon_and_osd_map(client) || (client->auth_err < 0),
-		       timeout);
+			have_mon_and_osd_map(client) || (client->auth_err < 0),
+			timeout);
 		if (err == -EINTR || err == -ERESTARTSYS)
-			goto out;
-		if (client->auth_err < 0) {
-			err = client->auth_err;
-			goto out;
-		}
+			return err;
+		if (client->auth_err < 0)
+			return client->auth_err;
 	}
 
+	return 0;
+}
+
+int ceph_open_session(struct ceph_client *client)
+{
+	int ret;
+	unsigned long started = jiffies;  /* note the start time */
+
+	dout("open_session start\n");
+	mutex_lock(&client->mount_mutex);
+
+	ret = __ceph_open_session(client, started);
+
+	mutex_unlock(&client->mount_mutex);
+	return ret;
+}
+
+/*
+ * mount: join the ceph cluster, and open root directory.
+ */
+static int ceph_mount(struct ceph_client *client, struct vfsmount *mnt,
+		      const char *path)
+{
+	int err;
+	unsigned long started = jiffies;  /* note the start time */
+	struct dentry *root;
+
+	dout("mount start\n");
+	mutex_lock(&client->mount_mutex);
+
+	err = __ceph_open_session(client, started);
+	if (err < 0)
+		goto out;
+
 	dout("mount opening root\n");
 	root = open_root_dentry(client, "", started);
 	if (IS_ERR(root)) {
@@ -963,7 +1061,7 @@ static int ceph_get_sb(struct file_system_type *fs_type,
 	}
 
 	/* create client (which we may/may not use) */
-	client = ceph_create_client(args);
+	client = ceph_create_client(args, 1);
 	if (IS_ERR(client)) {
 		err = PTR_ERR(client);
 		goto out_final;
@@ -1053,8 +1151,14 @@ static int __init init_ceph(void)
 		CEPH_MONC_PROTOCOL, CEPH_MDSC_PROTOCOL, CEPH_OSDC_PROTOCOL,
 		CEPH_OSDMAP_VERSION, CEPH_OSDMAP_VERSION_EXT,
 		CEPH_OSDMAP_INC_VERSION, CEPH_OSDMAP_INC_VERSION_EXT);
+
+	ret = rbd_init();
+	if (ret)
+		goto out_fs;
 	return 0;
 
+out_fs:
+	unregister_filesystem(&ceph_fs_type);
 out_icache:
 	destroy_caches();
 out_msgr:
@@ -1068,6 +1172,7 @@ out:
 static void __exit exit_ceph(void)
 {
 	dout("exit_ceph\n");
+	rbd_exit();
 	unregister_filesystem(&ceph_fs_type);
 	ceph_caps_finalize();
 	destroy_caches();
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 10a4a406e887..b46de1f40ec9 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -48,14 +48,11 @@
 #define ceph_test_opt(client, opt) \
 	(!!((client)->mount_args->flags & CEPH_OPT_##opt))
 
-
 struct ceph_mount_args {
 	int sb_flags;
 	int flags;
 	struct ceph_fsid fsid;
 	struct ceph_entity_addr my_addr;
-	int num_mon;
-	struct ceph_entity_addr *mon_addr;
 	int mount_timeout;
 	int osd_idle_ttl;
 	int osd_timeout;
@@ -67,9 +64,17 @@ struct ceph_mount_args {
 	int cap_release_safety;
 	int max_readdir;       /* max readdir result (entires) */
 	int max_readdir_bytes; /* max readdir result (bytes) */
+
+	/* any type that can't be simply compared or doesn't need
+	   need to be compared should go beyond this point,
+	   ceph_compare_mount_args() should be updated accordingly */
+	struct ceph_entity_addr *mon_addr; /* should be the first
+					      pointer type of args */
+	int num_mon;
 	char *snapdir_name;   /* default ".snap" */
 	char *name;
 	char *secret;
+	char *snap;	/* rbd snapshot */
 };
 
 /*
@@ -139,6 +144,8 @@ struct ceph_client {
 
 	int min_caps;                  /* min caps i added */
 
+	int have_mdsc;
+
 	struct ceph_messenger *msgr;   /* messenger instance */
 	struct ceph_mon_client monc;
 	struct ceph_mds_client mdsc;
@@ -737,6 +744,17 @@ extern struct kmem_cache *ceph_file_cachep;
 
 extern const char *ceph_msg_type_name(int type);
 extern int ceph_check_fsid(struct ceph_client *client, struct ceph_fsid *fsid);
+extern struct ceph_mount_args *parse_mount_args(int flags, char *options,
+						const char *dev_name,
+						const char **path);
+extern void ceph_destroy_mount_args(struct ceph_mount_args *args);
+extern int ceph_compare_mount_args(struct ceph_mount_args *new_args,
+			    struct ceph_client *client);
+extern struct ceph_client *ceph_create_client(struct ceph_mount_args *args,
+					      int need_mdsc);
+extern u64 ceph_client_id(struct ceph_client *client);
+extern void ceph_destroy_client(struct ceph_client *client);
+extern int ceph_open_session(struct ceph_client *client);
 
 #define FSID_FORMAT "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-" \
 	"%02x%02x%02x%02x%02x%02x"
@@ -847,6 +865,13 @@ extern int ceph_mmap(struct file *file, struct vm_area_struct *vma);
 /* file.c */
 extern const struct file_operations ceph_file_fops;
 extern const struct address_space_operations ceph_aops;
+extern int ceph_copy_to_page_vector(struct page **pages,
+				    const char *data,
+				    loff_t off, size_t len);
+extern int ceph_copy_from_page_vector(struct page **pages,
+				    char *data,
+				    loff_t off, size_t len);
+extern struct page **ceph_alloc_page_vector(int num_pages, gfp_t flags);
 extern int ceph_open(struct inode *inode, struct file *file);
 extern struct dentry *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
 				       struct nameidata *nd, int mode,
@@ -896,4 +921,9 @@ static inline struct inode *get_dentry_parent_inode(struct dentry *dentry)
 	return NULL;
 }
 
+#ifndef CONFIG_RBD
+static inline int __init rbd_init(void) { return 0; }
+static inline void __exit rbd_exit(void) {}
+#endif
+
 #endif /* _FS_CEPH_SUPER_H */