From 00d7e0e572c0fbe3521a2d1ffb6cc704e1abd2eb Mon Sep 17 00:00:00 2001
Message-Id: <00d7e0e572c0fbe3521a2d1ffb6cc704e1abd2eb.1376495567.git.minovotn@redhat.com>
From: Kevin Wolf <kwolf@redhat.com>
Date: Wed, 14 Aug 2013 08:52:45 +0200
Subject: [PATCH 1/6] ceph/rbd block driver for qemu-kvm

RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <1376470370-32441-2-git-send-email-kwolf@redhat.com>
Patchwork-id: 53329
O-Subject: [RHEL-6.5 qemu-kvm PATCH 1/6] ceph/rbd block driver for qemu-kvm
Bugzilla: 988079
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

From: Christian Brunner <chb@muc.de>

Bugzilla: 988079

This imports the upstream rbd driver as of today with patches reverted
and small changes applied to supposedly make it build in the RHEL 6 tree
(this isn't actually tested because it won't be built anyway: the
check in configure will disable it)

The closest upstream state should be that of commit dc7588c1.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 Makefile.objs |    1 +
 block/rbd.c   | 1003 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 configure     |   52 +++
 3 files changed, 1056 insertions(+)
 create mode 100644 block/rbd.c

Signed-off-by: Michal Novotny <minovotn@redhat.com>
---
 Makefile.objs |    1 +
 block/rbd.c   | 1003 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 configure     |   52 +++
 3 files changed, 1056 insertions(+)
 create mode 100644 block/rbd.c

diff --git a/Makefile.objs b/Makefile.objs
index 2e9bdc3..d6815ef 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -32,6 +32,7 @@ block-nested-$(CONFIG_WIN32) += raw-win32.o
 block-nested-$(CONFIG_POSIX) += raw-posix.o
 block-nested-$(CONFIG_CURL) += curl.o
 block-nested-$(CONFIG_GLUSTERFS) += gluster.o
+block-nested-$(CONFIG_RBD) += rbd.o
 
 block-obj-y +=  $(addprefix block/, $(block-nested-y))
 
diff --git a/block/rbd.c b/block/rbd.c
new file mode 100644
index 0000000..448bed1
--- /dev/null
+++ b/block/rbd.c
@@ -0,0 +1,1003 @@
+/*
+ * QEMU Block driver for RADOS (Ceph)
+ *
+ * Copyright (C) 2010-2011 Christian Brunner <chb@muc.de>,
+ *                         Josh Durgin <josh.durgin@dreamhost.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ */
+
+#include <inttypes.h>
+
+#include "qemu-common.h"
+#include "qemu-error.h"
+#include "block_int.h"
+
+#include <rbd/librbd.h>
+
+/*
+ * When specifying the image filename use:
+ *
+ * rbd:poolname/devicename[@snapshotname][:option1=value1[:option2=value2...]]
+ *
+ * poolname must be the name of an existing rados pool.
+ *
+ * devicename is the name of the rbd image.
+ *
+ * Each option given is used to configure rados, and may be any valid
+ * Ceph option, "id", or "conf".
+ *
+ * The "id" option indicates what user we should authenticate as to
+ * the Ceph cluster.  If it is excluded we will use the Ceph default
+ * (normally 'admin').
+ *
+ * The "conf" option specifies a Ceph configuration file to read.  If
+ * it is not specified, we will read from the default Ceph locations
+ * (e.g., /etc/ceph/ceph.conf).  To avoid reading _any_ configuration
+ * file, specify conf=/dev/null.
+ *
+ * Configuration values containing :, @, or = can be escaped with a
+ * leading "\".
+ */
+
+/* rbd_aio_discard added in 0.1.2 */
+#if LIBRBD_VERSION_CODE >= LIBRBD_VERSION(0, 1, 2)
+#define LIBRBD_SUPPORTS_DISCARD
+#else
+#undef LIBRBD_SUPPORTS_DISCARD
+#endif
+
+#define OBJ_MAX_SIZE (1UL << OBJ_DEFAULT_OBJ_ORDER)
+
+#define RBD_MAX_CONF_NAME_SIZE 128
+#define RBD_MAX_CONF_VAL_SIZE 512
+#define RBD_MAX_CONF_SIZE 1024
+#define RBD_MAX_POOL_NAME_SIZE 128
+#define RBD_MAX_SNAP_NAME_SIZE 128
+#define RBD_MAX_SNAPS 100
+
+typedef enum {
+    RBD_AIO_READ,
+    RBD_AIO_WRITE,
+    RBD_AIO_DISCARD,
+    RBD_AIO_FLUSH
+} RBDAIOCmd;
+
+typedef struct RBDAIOCB {
+    BlockDriverAIOCB common;
+    QEMUBH *bh;
+    int64_t ret;
+    QEMUIOVector *qiov;
+    char *bounce;
+    RBDAIOCmd cmd;
+    int64_t sector_num;
+    int error;
+    struct BDRVRBDState *s;
+    int cancelled;
+    int status;
+} RBDAIOCB;
+
+typedef struct RADOSCB {
+    int rcbid;
+    RBDAIOCB *acb;
+    struct BDRVRBDState *s;
+    int done;
+    int64_t size;
+    char *buf;
+    int64_t ret;
+} RADOSCB;
+
+#define RBD_FD_READ 0
+#define RBD_FD_WRITE 1
+
+typedef struct BDRVRBDState {
+    int fds[2];
+    rados_t cluster;
+    rados_ioctx_t io_ctx;
+    rbd_image_t image;
+    char name[RBD_MAX_IMAGE_NAME_SIZE];
+    int qemu_aio_count;
+    char *snap;
+    int event_reader_pos;
+    RADOSCB *event_rcb;
+} BDRVRBDState;
+
+static void rbd_aio_bh_cb(void *opaque);
+
+static int qemu_rbd_next_tok(char *dst, int dst_len,
+                             char *src, char delim,
+                             const char *name,
+                             char **p)
+{
+    int l;
+    char *end;
+
+    *p = NULL;
+
+    if (delim != '\0') {
+        for (end = src; *end; ++end) {
+            if (*end == delim) {
+                break;
+            }
+            if (*end == '\\' && end[1] != '\0') {
+                end++;
+            }
+        }
+        if (*end == delim) {
+            *p = end + 1;
+            *end = '\0';
+        }
+    }
+    l = strlen(src);
+    if (l >= dst_len) {
+        error_report("%s too long", name);
+        return -EINVAL;
+    } else if (l == 0) {
+        error_report("%s too short", name);
+        return -EINVAL;
+    }
+
+    pstrcpy(dst, dst_len, src);
+
+    return 0;
+}
+
+static void qemu_rbd_unescape(char *src)
+{
+    char *p;
+
+    for (p = src; *src; ++src, ++p) {
+        if (*src == '\\' && src[1] != '\0') {
+            src++;
+        }
+        *p = *src;
+    }
+    *p = '\0';
+}
+
+static int qemu_rbd_parsename(const char *filename,
+                              char *pool, int pool_len,
+                              char *snap, int snap_len,
+                              char *name, int name_len,
+                              char *conf, int conf_len)
+{
+    const char *start;
+    char *p, *buf;
+    int ret;
+
+    if (!strstart(filename, "rbd:", &start)) {
+        return -EINVAL;
+    }
+
+    buf = g_strdup(start);
+    p = buf;
+    *snap = '\0';
+    *conf = '\0';
+
+    ret = qemu_rbd_next_tok(pool, pool_len, p, '/', "pool name", &p);
+    if (ret < 0 || !p) {
+        ret = -EINVAL;
+        goto done;
+    }
+    qemu_rbd_unescape(pool);
+
+    if (strchr(p, '@')) {
+        ret = qemu_rbd_next_tok(name, name_len, p, '@', "object name", &p);
+        if (ret < 0) {
+            goto done;
+        }
+        ret = qemu_rbd_next_tok(snap, snap_len, p, ':', "snap name", &p);
+        qemu_rbd_unescape(snap);
+    } else {
+        ret = qemu_rbd_next_tok(name, name_len, p, ':', "object name", &p);
+    }
+    qemu_rbd_unescape(name);
+    if (ret < 0 || !p) {
+        goto done;
+    }
+
+    ret = qemu_rbd_next_tok(conf, conf_len, p, '\0', "configuration", &p);
+
+done:
+    g_free(buf);
+    return ret;
+}
+
+static char *qemu_rbd_parse_clientname(const char *conf, char *clientname)
+{
+    const char *p = conf;
+
+    while (*p) {
+        int len;
+        const char *end = strchr(p, ':');
+
+        if (end) {
+            len = end - p;
+        } else {
+            len = strlen(p);
+        }
+
+        if (strncmp(p, "id=", 3) == 0) {
+            len -= 3;
+            strncpy(clientname, p + 3, len);
+            clientname[len] = '\0';
+            return clientname;
+        }
+        if (end == NULL) {
+            break;
+        }
+        p = end + 1;
+    }
+    return NULL;
+}
+
+static int qemu_rbd_set_conf(rados_t cluster, const char *conf)
+{
+    char *p, *buf;
+    char name[RBD_MAX_CONF_NAME_SIZE];
+    char value[RBD_MAX_CONF_VAL_SIZE];
+    int ret = 0;
+
+    buf = g_strdup(conf);
+    p = buf;
+
+    while (p) {
+        ret = qemu_rbd_next_tok(name, sizeof(name), p,
+                                '=', "conf option name", &p);
+        if (ret < 0) {
+            break;
+        }
+        qemu_rbd_unescape(name);
+
+        if (!p) {
+            error_report("conf option %s has no value", name);
+            ret = -EINVAL;
+            break;
+        }
+
+        ret = qemu_rbd_next_tok(value, sizeof(value), p,
+                                ':', "conf option value", &p);
+        if (ret < 0) {
+            break;
+        }
+        qemu_rbd_unescape(value);
+
+        if (strcmp(name, "conf") == 0) {
+            ret = rados_conf_read_file(cluster, value);
+            if (ret < 0) {
+                error_report("error reading conf file %s", value);
+                break;
+            }
+        } else if (strcmp(name, "id") == 0) {
+            /* ignore, this is parsed by qemu_rbd_parse_clientname() */
+        } else {
+            ret = rados_conf_set(cluster, name, value);
+            if (ret < 0) {
+                error_report("invalid conf option %s", name);
+                ret = -EINVAL;
+                break;
+            }
+        }
+    }
+
+    g_free(buf);
+    return ret;
+}
+
+static int qemu_rbd_create(const char *filename, QEMUOptionParameter *options)
+{
+    int64_t bytes = 0;
+    int64_t objsize;
+    int obj_order = 0;
+    char pool[RBD_MAX_POOL_NAME_SIZE];
+    char name[RBD_MAX_IMAGE_NAME_SIZE];
+    char snap_buf[RBD_MAX_SNAP_NAME_SIZE];
+    char conf[RBD_MAX_CONF_SIZE];
+    char clientname_buf[RBD_MAX_CONF_SIZE];
+    char *clientname;
+    rados_t cluster;
+    rados_ioctx_t io_ctx;
+    int ret;
+
+    if (qemu_rbd_parsename(filename, pool, sizeof(pool),
+                           snap_buf, sizeof(snap_buf),
+                           name, sizeof(name),
+                           conf, sizeof(conf)) < 0) {
+        return -EINVAL;
+    }
+
+    /* Read out options */
+    while (options && options->name) {
+        if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
+            bytes = options->value.n;
+        } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
+            if (options->value.n) {
+                objsize = options->value.n;
+                if ((objsize - 1) & objsize) {    /* not a power of 2? */
+                    error_report("obj size needs to be power of 2");
+                    return -EINVAL;
+                }
+                if (objsize < 4096) {
+                    error_report("obj size too small");
+                    return -EINVAL;
+                }
+                obj_order = ffs(objsize) - 1;
+            }
+        }
+        options++;
+    }
+
+    clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
+    if (rados_create(&cluster, clientname) < 0) {
+        error_report("error initializing");
+        return -EIO;
+    }
+
+    if (strstr(conf, "conf=") == NULL) {
+        /* try default location, but ignore failure */
+        rados_conf_read_file(cluster, NULL);
+    }
+
+    if (conf[0] != '\0' &&
+        qemu_rbd_set_conf(cluster, conf) < 0) {
+        error_report("error setting config options");
+        rados_shutdown(cluster);
+        return -EIO;
+    }
+
+    if (rados_connect(cluster) < 0) {
+        error_report("error connecting");
+        rados_shutdown(cluster);
+        return -EIO;
+    }
+
+    if (rados_ioctx_create(cluster, pool, &io_ctx) < 0) {
+        error_report("error opening pool %s", pool);
+        rados_shutdown(cluster);
+        return -EIO;
+    }
+
+    ret = rbd_create(io_ctx, name, bytes, &obj_order);
+    rados_ioctx_destroy(io_ctx);
+    rados_shutdown(cluster);
+
+    return ret;
+}
+
+/*
+ * This aio completion is being called from qemu_rbd_aio_event_reader()
+ * and runs in qemu context. It schedules a bh, but just in case the aio
+ * was not cancelled before.
+ */
+static void qemu_rbd_complete_aio(RADOSCB *rcb)
+{
+    RBDAIOCB *acb = rcb->acb;
+    int64_t r;
+
+    r = rcb->ret;
+
+    if (acb->cmd != RBD_AIO_READ) {
+        if (r < 0) {
+            acb->ret = r;
+            acb->error = 1;
+        } else if (!acb->error) {
+            acb->ret = rcb->size;
+        }
+    } else {
+        if (r < 0) {
+            memset(rcb->buf, 0, rcb->size);
+            acb->ret = r;
+            acb->error = 1;
+        } else if (r < rcb->size) {
+            memset(rcb->buf + r, 0, rcb->size - r);
+            if (!acb->error) {
+                acb->ret = rcb->size;
+            }
+        } else if (!acb->error) {
+            acb->ret = r;
+        }
+    }
+    /* Note that acb->bh can be NULL in case where the aio was cancelled */
+    acb->bh = qemu_bh_new(rbd_aio_bh_cb, acb);
+    qemu_bh_schedule(acb->bh);
+    g_free(rcb);
+}
+
+/*
+ * aio fd read handler. It runs in the qemu context and calls the
+ * completion handling of completed rados aio operations.
+ */
+static void qemu_rbd_aio_event_reader(void *opaque)
+{
+    BDRVRBDState *s = opaque;
+
+    ssize_t ret;
+
+    do {
+        char *p = (char *)&s->event_rcb;
+
+        /* now read the rcb pointer that was sent from a non qemu thread */
+        ret = read(s->fds[RBD_FD_READ], p + s->event_reader_pos,
+                   sizeof(s->event_rcb) - s->event_reader_pos);
+        if (ret > 0) {
+            s->event_reader_pos += ret;
+            if (s->event_reader_pos == sizeof(s->event_rcb)) {
+                s->event_reader_pos = 0;
+                qemu_rbd_complete_aio(s->event_rcb);
+                s->qemu_aio_count--;
+            }
+        }
+    } while (ret < 0 && errno == EINTR);
+}
+
+static int qemu_rbd_aio_flush_cb(void *opaque)
+{
+    BDRVRBDState *s = opaque;
+
+    return (s->qemu_aio_count > 0);
+}
+
+static int qemu_rbd_open(BlockDriverState *bs, const char *filename, int flags)
+{
+    BDRVRBDState *s = bs->opaque;
+    char pool[RBD_MAX_POOL_NAME_SIZE];
+    char snap_buf[RBD_MAX_SNAP_NAME_SIZE];
+    char conf[RBD_MAX_CONF_SIZE];
+    char clientname_buf[RBD_MAX_CONF_SIZE];
+    char *clientname;
+    int r;
+
+    if (qemu_rbd_parsename(filename, pool, sizeof(pool),
+                           snap_buf, sizeof(snap_buf),
+                           s->name, sizeof(s->name),
+                           conf, sizeof(conf)) < 0) {
+        return -EINVAL;
+    }
+
+    clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
+    r = rados_create(&s->cluster, clientname);
+    if (r < 0) {
+        error_report("error initializing");
+        return r;
+    }
+
+    s->snap = NULL;
+    if (snap_buf[0] != '\0') {
+        s->snap = g_strdup(snap_buf);
+    }
+
+    /*
+     * Fallback to more conservative semantics if setting cache
+     * options fails. Ignore errors from setting rbd_cache because the
+     * only possible error is that the option does not exist, and
+     * librbd defaults to no caching. If write through caching cannot
+     * be set up, fall back to no caching.
+     */
+    if (flags & BDRV_O_NOCACHE) {
+        rados_conf_set(s->cluster, "rbd_cache", "false");
+    } else {
+        rados_conf_set(s->cluster, "rbd_cache", "true");
+        if (!(flags & BDRV_O_CACHE_WB)) {
+            r = rados_conf_set(s->cluster, "rbd_cache_max_dirty", "0");
+            if (r < 0) {
+                rados_conf_set(s->cluster, "rbd_cache", "false");
+            }
+        }
+    }
+
+    if (strstr(conf, "conf=") == NULL) {
+        /* try default location, but ignore failure */
+        rados_conf_read_file(s->cluster, NULL);
+    }
+
+    if (conf[0] != '\0') {
+        r = qemu_rbd_set_conf(s->cluster, conf);
+        if (r < 0) {
+            error_report("error setting config options");
+            goto failed_shutdown;
+        }
+    }
+
+    r = rados_connect(s->cluster);
+    if (r < 0) {
+        error_report("error connecting");
+        goto failed_shutdown;
+    }
+
+    r = rados_ioctx_create(s->cluster, pool, &s->io_ctx);
+    if (r < 0) {
+        error_report("error opening pool %s", pool);
+        goto failed_shutdown;
+    }
+
+    r = rbd_open(s->io_ctx, s->name, &s->image, s->snap);
+    if (r < 0) {
+        error_report("error reading header from %s", s->name);
+        goto failed_open;
+    }
+
+    bs->read_only = (s->snap != NULL);
+
+    s->event_reader_pos = 0;
+    r = qemu_pipe(s->fds);
+    if (r < 0) {
+        error_report("error opening eventfd");
+        goto failed;
+    }
+    fcntl(s->fds[0], F_SETFL, O_NONBLOCK);
+    fcntl(s->fds[1], F_SETFL, O_NONBLOCK);
+    qemu_aio_set_fd_handler(s->fds[RBD_FD_READ], qemu_rbd_aio_event_reader,
+                            NULL, qemu_rbd_aio_flush_cb, NULL, s);
+
+
+    return 0;
+
+failed:
+    rbd_close(s->image);
+failed_open:
+    rados_ioctx_destroy(s->io_ctx);
+failed_shutdown:
+    rados_shutdown(s->cluster);
+    g_free(s->snap);
+    return r;
+}
+
+static void qemu_rbd_close(BlockDriverState *bs)
+{
+    BDRVRBDState *s = bs->opaque;
+
+    close(s->fds[0]);
+    close(s->fds[1]);
+    qemu_aio_set_fd_handler(s->fds[RBD_FD_READ], NULL, NULL, NULL, NULL, NULL);
+
+    rbd_close(s->image);
+    rados_ioctx_destroy(s->io_ctx);
+    g_free(s->snap);
+    rados_shutdown(s->cluster);
+}
+
+/*
+ * Cancel aio. Since we don't reference acb in a non qemu threads,
+ * it is safe to access it here.
+ */
+static void qemu_rbd_aio_cancel(BlockDriverAIOCB *blockacb)
+{
+    RBDAIOCB *acb = (RBDAIOCB *) blockacb;
+    acb->cancelled = 1;
+
+    while (acb->status == -EINPROGRESS) {
+        qemu_aio_wait();
+    }
+
+    qemu_aio_release(acb);
+}
+
+static AIOPool rbd_aiocb_info = {
+    .aiocb_size = sizeof(RBDAIOCB),
+    .cancel = qemu_rbd_aio_cancel,
+};
+
+static int qemu_rbd_send_pipe(BDRVRBDState *s, RADOSCB *rcb)
+{
+    int ret = 0;
+    while (1) {
+        fd_set wfd;
+        int fd = s->fds[RBD_FD_WRITE];
+
+        /* send the op pointer to the qemu thread that is responsible
+           for the aio/op completion. Must do it in a qemu thread context */
+        ret = write(fd, (void *)&rcb, sizeof(rcb));
+        if (ret >= 0) {
+            break;
+        }
+        if (errno == EINTR) {
+            continue;
+        }
+        if (errno != EAGAIN) {
+            break;
+        }
+
+        FD_ZERO(&wfd);
+        FD_SET(fd, &wfd);
+        do {
+            ret = select(fd + 1, NULL, &wfd, NULL, NULL);
+        } while (ret < 0 && errno == EINTR);
+    }
+
+    return ret;
+}
+
+/*
+ * This is the callback function for rbd_aio_read and _write
+ *
+ * Note: this function is being called from a non qemu thread so
+ * we need to be careful about what we do here. Generally we only
+ * write to the block notification pipe, and do the rest of the
+ * io completion handling from qemu_rbd_aio_event_reader() which
+ * runs in a qemu context.
+ */
+static void rbd_finish_aiocb(rbd_completion_t c, RADOSCB *rcb)
+{
+    int ret;
+    rcb->ret = rbd_aio_get_return_value(c);
+    rbd_aio_release(c);
+    ret = qemu_rbd_send_pipe(rcb->s, rcb);
+    if (ret < 0) {
+        error_report("failed writing to acb->s->fds");
+        g_free(rcb);
+    }
+}
+
+/* Callback when all queued rbd_aio requests are complete */
+
+static void rbd_aio_bh_cb(void *opaque)
+{
+    RBDAIOCB *acb = opaque;
+
+    if (acb->cmd == RBD_AIO_READ) {
+        qemu_iovec_from_buffer(acb->qiov, acb->bounce, acb->qiov->size);
+    }
+    qemu_vfree(acb->bounce);
+    acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
+    qemu_bh_delete(acb->bh);
+    acb->bh = NULL;
+    acb->status = 0;
+
+    if (!acb->cancelled) {
+        qemu_aio_release(acb);
+    }
+}
+
+static int rbd_aio_discard_wrapper(rbd_image_t image,
+                                   uint64_t off,
+                                   uint64_t len,
+                                   rbd_completion_t comp)
+{
+#ifdef LIBRBD_SUPPORTS_DISCARD
+    return rbd_aio_discard(image, off, len, comp);
+#else
+    return -ENOTSUP;
+#endif
+}
+
+static int rbd_aio_flush_wrapper(rbd_image_t image,
+                                 rbd_completion_t comp)
+{
+#ifdef LIBRBD_SUPPORTS_AIO_FLUSH
+    return rbd_aio_flush(image, comp);
+#else
+    return -ENOTSUP;
+#endif
+}
+
+static BlockDriverAIOCB *rbd_start_aio(BlockDriverState *bs,
+                                       int64_t sector_num,
+                                       QEMUIOVector *qiov,
+                                       int nb_sectors,
+                                       BlockDriverCompletionFunc *cb,
+                                       void *opaque,
+                                       RBDAIOCmd cmd)
+{
+    RBDAIOCB *acb;
+    RADOSCB *rcb;
+    rbd_completion_t c;
+    int64_t off, size;
+    char *buf;
+    int r;
+
+    BDRVRBDState *s = bs->opaque;
+
+    acb = qemu_aio_get(&rbd_aiocb_info, bs, cb, opaque);
+    acb->cmd = cmd;
+    acb->qiov = qiov;
+    if (cmd == RBD_AIO_DISCARD || cmd == RBD_AIO_FLUSH) {
+        acb->bounce = NULL;
+    } else {
+        acb->bounce = qemu_blockalign(bs, qiov->size);
+    }
+    acb->ret = 0;
+    acb->error = 0;
+    acb->s = s;
+    acb->cancelled = 0;
+    acb->bh = NULL;
+    acb->status = -EINPROGRESS;
+
+    if (cmd == RBD_AIO_WRITE) {
+        qemu_iovec_to_buffer(acb->qiov, acb->bounce);
+    }
+
+    buf = acb->bounce;
+
+    off = sector_num * BDRV_SECTOR_SIZE;
+    size = nb_sectors * BDRV_SECTOR_SIZE;
+
+    s->qemu_aio_count++; /* All the RADOSCB */
+
+    rcb = g_malloc(sizeof(RADOSCB));
+    rcb->done = 0;
+    rcb->acb = acb;
+    rcb->buf = buf;
+    rcb->s = acb->s;
+    rcb->size = size;
+    r = rbd_aio_create_completion(rcb, (rbd_callback_t) rbd_finish_aiocb, &c);
+    if (r < 0) {
+        goto failed;
+    }
+
+    switch (cmd) {
+    case RBD_AIO_WRITE:
+        r = rbd_aio_write(s->image, off, size, buf, c);
+        break;
+    case RBD_AIO_READ:
+        r = rbd_aio_read(s->image, off, size, buf, c);
+        break;
+    case RBD_AIO_DISCARD:
+        r = rbd_aio_discard_wrapper(s->image, off, size, c);
+        break;
+    case RBD_AIO_FLUSH:
+        r = rbd_aio_flush_wrapper(s->image, c);
+        break;
+    default:
+        r = -EINVAL;
+    }
+
+    if (r < 0) {
+        goto failed;
+    }
+
+    return &acb->common;
+
+failed:
+    g_free(rcb);
+    s->qemu_aio_count--;
+    qemu_aio_release(acb);
+    return NULL;
+}
+
+static BlockDriverAIOCB *qemu_rbd_aio_readv(BlockDriverState *bs,
+                                            int64_t sector_num,
+                                            QEMUIOVector *qiov,
+                                            int nb_sectors,
+                                            BlockDriverCompletionFunc *cb,
+                                            void *opaque)
+{
+    return rbd_start_aio(bs, sector_num, qiov, nb_sectors, cb, opaque,
+                         RBD_AIO_READ);
+}
+
+static BlockDriverAIOCB *qemu_rbd_aio_writev(BlockDriverState *bs,
+                                             int64_t sector_num,
+                                             QEMUIOVector *qiov,
+                                             int nb_sectors,
+                                             BlockDriverCompletionFunc *cb,
+                                             void *opaque)
+{
+    return rbd_start_aio(bs, sector_num, qiov, nb_sectors, cb, opaque,
+                         RBD_AIO_WRITE);
+}
+
+#ifdef LIBRBD_SUPPORTS_AIO_FLUSH
+static BlockDriverAIOCB *qemu_rbd_aio_flush(BlockDriverState *bs,
+                                            BlockDriverCompletionFunc *cb,
+                                            void *opaque)
+{
+    return rbd_start_aio(bs, 0, NULL, 0, cb, opaque, RBD_AIO_FLUSH);
+}
+
+#else
+
+static int qemu_rbd_co_flush(BlockDriverState *bs)
+{
+#if LIBRBD_VERSION_CODE >= LIBRBD_VERSION(0, 1, 1)
+    /* rbd_flush added in 0.1.1 */
+    BDRVRBDState *s = bs->opaque;
+    return rbd_flush(s->image);
+#else
+    return 0;
+#endif
+}
+#endif
+
+static int qemu_rbd_getinfo(BlockDriverState *bs, BlockDriverInfo *bdi)
+{
+    BDRVRBDState *s = bs->opaque;
+    rbd_image_info_t info;
+    int r;
+
+    r = rbd_stat(s->image, &info, sizeof(info));
+    if (r < 0) {
+        return r;
+    }
+
+    bdi->cluster_size = info.obj_size;
+    return 0;
+}
+
+static int64_t qemu_rbd_getlength(BlockDriverState *bs)
+{
+    BDRVRBDState *s = bs->opaque;
+    rbd_image_info_t info;
+    int r;
+
+    r = rbd_stat(s->image, &info, sizeof(info));
+    if (r < 0) {
+        return r;
+    }
+
+    return info.size;
+}
+
+static int qemu_rbd_truncate(BlockDriverState *bs, int64_t offset)
+{
+    BDRVRBDState *s = bs->opaque;
+    int r;
+
+    r = rbd_resize(s->image, offset);
+    if (r < 0) {
+        return r;
+    }
+
+    return 0;
+}
+
+static int qemu_rbd_snap_create(BlockDriverState *bs,
+                                QEMUSnapshotInfo *sn_info)
+{
+    BDRVRBDState *s = bs->opaque;
+    int r;
+
+    if (sn_info->name[0] == '\0') {
+        return -EINVAL; /* we need a name for rbd snapshots */
+    }
+
+    /*
+     * rbd snapshots are using the name as the user controlled unique identifier
+     * we can't use the rbd snapid for that purpose, as it can't be set
+     */
+    if (sn_info->id_str[0] != '\0' &&
+        strcmp(sn_info->id_str, sn_info->name) != 0) {
+        return -EINVAL;
+    }
+
+    if (strlen(sn_info->name) >= sizeof(sn_info->id_str)) {
+        return -ERANGE;
+    }
+
+    r = rbd_snap_create(s->image, sn_info->name);
+    if (r < 0) {
+        error_report("failed to create snap: %s", strerror(-r));
+        return r;
+    }
+
+    return 0;
+}
+
+static int qemu_rbd_snap_remove(BlockDriverState *bs,
+                                const char *snapshot_name)
+{
+    BDRVRBDState *s = bs->opaque;
+    int r;
+
+    r = rbd_snap_remove(s->image, snapshot_name);
+    return r;
+}
+
+static int qemu_rbd_snap_rollback(BlockDriverState *bs,
+                                  const char *snapshot_name)
+{
+    BDRVRBDState *s = bs->opaque;
+    int r;
+
+    r = rbd_snap_rollback(s->image, snapshot_name);
+    return r;
+}
+
+static int qemu_rbd_snap_list(BlockDriverState *bs,
+                              QEMUSnapshotInfo **psn_tab)
+{
+    BDRVRBDState *s = bs->opaque;
+    QEMUSnapshotInfo *sn_info, *sn_tab = NULL;
+    int i, snap_count;
+    rbd_snap_info_t *snaps;
+    int max_snaps = RBD_MAX_SNAPS;
+
+    do {
+        snaps = g_malloc(sizeof(*snaps) * max_snaps);
+        snap_count = rbd_snap_list(s->image, snaps, &max_snaps);
+        if (snap_count < 0) {
+            g_free(snaps);
+        }
+    } while (snap_count == -ERANGE);
+
+    if (snap_count <= 0) {
+        goto done;
+    }
+
+    sn_tab = g_malloc0(snap_count * sizeof(QEMUSnapshotInfo));
+
+    for (i = 0; i < snap_count; i++) {
+        const char *snap_name = snaps[i].name;
+
+        sn_info = sn_tab + i;
+        pstrcpy(sn_info->id_str, sizeof(sn_info->id_str), snap_name);
+        pstrcpy(sn_info->name, sizeof(sn_info->name), snap_name);
+
+        sn_info->vm_state_size = snaps[i].size;
+        sn_info->date_sec = 0;
+        sn_info->date_nsec = 0;
+        sn_info->vm_clock_nsec = 0;
+    }
+    rbd_snap_list_end(snaps);
+
+ done:
+    *psn_tab = sn_tab;
+    return snap_count;
+}
+
+#ifdef LIBRBD_SUPPORTS_DISCARD
+static BlockDriverAIOCB* qemu_rbd_aio_discard(BlockDriverState *bs,
+                                              int64_t sector_num,
+                                              int nb_sectors,
+                                              BlockDriverCompletionFunc *cb,
+                                              void *opaque)
+{
+    return rbd_start_aio(bs, sector_num, NULL, nb_sectors, cb, opaque,
+                         RBD_AIO_DISCARD);
+}
+#endif
+
+static QEMUOptionParameter qemu_rbd_create_options[] = {
+    {
+     .name = BLOCK_OPT_SIZE,
+     .type = OPT_SIZE,
+     .help = "Virtual disk size"
+    },
+    {
+     .name = BLOCK_OPT_CLUSTER_SIZE,
+     .type = OPT_SIZE,
+     .help = "RBD object size"
+    },
+    {NULL}
+};
+
+static BlockDriver bdrv_rbd = {
+    .format_name        = "rbd",
+    .instance_size      = sizeof(BDRVRBDState),
+    .bdrv_file_open     = qemu_rbd_open,
+    .bdrv_close         = qemu_rbd_close,
+    .bdrv_create        = qemu_rbd_create,
+    .bdrv_get_info      = qemu_rbd_getinfo,
+    .create_options     = qemu_rbd_create_options,
+    .bdrv_getlength     = qemu_rbd_getlength,
+    .bdrv_truncate      = qemu_rbd_truncate,
+    .protocol_name      = "rbd",
+
+    .bdrv_aio_readv         = qemu_rbd_aio_readv,
+    .bdrv_aio_writev        = qemu_rbd_aio_writev,
+
+#ifdef LIBRBD_SUPPORTS_AIO_FLUSH
+    .bdrv_aio_flush         = qemu_rbd_aio_flush,
+#else
+    .bdrv_co_flush          = qemu_rbd_co_flush,
+#endif
+
+#ifdef LIBRBD_SUPPORTS_DISCARD
+    .bdrv_aio_discard       = qemu_rbd_aio_discard,
+#endif
+
+    .bdrv_snapshot_create   = qemu_rbd_snap_create,
+    .bdrv_snapshot_delete   = qemu_rbd_snap_remove,
+    .bdrv_snapshot_list     = qemu_rbd_snap_list,
+    .bdrv_snapshot_goto     = qemu_rbd_snap_rollback,
+};
+
+static void bdrv_rbd_init(void)
+{
+    bdrv_register(&bdrv_rbd);
+}
+
+block_init(bdrv_rbd_init);
diff --git a/configure b/configure
index d9987f9..1f932d8 100755
--- a/configure
+++ b/configure
@@ -284,6 +284,7 @@ zero_malloc=""
 trace_backend="nop"
 fake_machine="no"
 spice=""
+rbd=""
 smartcard=""
 smartcard_nss=""
 live_snapshots="yes"
@@ -723,6 +724,10 @@ for opt do
   ;;
   --enable-glusterfs) glusterfs="yes"
   ;;
+  --disable-rbd) rbd="no"
+  ;;
+  --enable-rbd) rbd="yes"
+  ;;
   *) echo "ERROR: unknown option $opt"; show_help="yes"
   ;;
   esac
@@ -895,6 +900,7 @@ echo "  --disable-fake-machine   disable -fake-machine option"
 echo "  --enable-fake-machine    enable -fake-machine option"
 echo "  --disable-spice          disable spice"
 echo "  --enable-spice           enable spice"
+echo "  --enable-rbd             enable building the rados block device (rbd)"
 echo "  --disable-smartcard      disable smartcard support"
 echo "  --enable-smartcard       enable smartcard support"
 echo "  --disable-smartcard-nss  disable smartcard nss support"
@@ -1735,6 +1741,48 @@ if test "$mingw32" != yes -a "$pthread" = no; then
 fi
 
 ##########################################
+# rbd probe
+if test "$rbd" != "no" ; then
+  cat > $TMPC <<EOF
+#include <stdio.h>
+#include <rados/librados.h>
+int main(void) { rados_initialize(0, NULL); return 0; }
+EOF
+  rbd_libs="-lrados -lcrypto"
+  if compile_prog "" "$rbd_libs" ; then
+    librados_too_old=no
+    cat > $TMPC <<EOF
+#include <stdio.h>
+#include <rados/librados.h>
+#ifndef CEPH_OSD_TMAP_SET
+#error missing CEPH_OSD_TMAP_SET
+#endif
+int main(void) {
+    int (*func)(const rados_pool_t pool, uint64_t *snapid) = rados_selfmanaged_snap_create;
+    rados_initialize(0, NULL);
+    return 0;
+}
+EOF
+    if compile_prog "" "$rbd_libs" ; then
+      rbd=yes
+      libs_tools="$rbd_libs $libs_tools"
+      libs_softmmu="$rbd_libs $libs_softmmu"
+    else
+      rbd=no
+      librados_too_old=yes
+    fi
+  else
+    if test "$rbd" = "yes" ; then
+      feature_not_found "rados block device"
+    fi
+    rbd=no
+  fi
+  if test "$librados_too_old" = "yes" ; then
+    echo "-> Your librados version is too old - upgrade needed to have rbd support"
+  fi
+fi
+
+##########################################
 # linux-aio probe
 
 if test "$linux_aio" != "no" ; then
@@ -2375,6 +2423,7 @@ echo "vhost-net support $vhost_net"
 echo "-fake-machine     $fake_machine"
 echo "Trace backend     $trace_backend"
 echo "spice support     $spice ($spice_protocol_version/$spice_server_version)"
+echo "rbd support       $rbd"
 echo "nss used          $smartcard_nss"
 echo "Live snapshots    $live_snapshots"
 echo "Block streaming   $block_stream"
@@ -2666,6 +2715,9 @@ echo "CONFIG_UNAME_RELEASE=\"$uname_release\"" >> $config_host_mak
 if test "$zero_malloc" = "yes" ; then
   echo "CONFIG_ZERO_MALLOC=y" >> $config_host_mak
 fi
+if test "$rbd" = "yes" ; then
+  echo "CONFIG_RBD=y" >> $config_host_mak
+fi
 
 if test "$has_environ" = "yes" ; then
   echo "CONFIG_HAS_ENVIRON=y" >> $config_host_mak
-- 
1.7.11.7

