Add qemu 2.4.0

Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>

1 files changed, 967 insertions, 0 deletions

diff --git a/qemu/block/rbd.c b/qemu/block/rbd.c
new file mode 100644
index 000000000..a60a19d58
--- /dev/null
+++ b/qemu/block/rbd.c
@@ -0,0 +1,967 @@
+/*
+ * 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-report.h"
+#include "block/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 {
+    BlockAIOCB common;
+    QEMUBH *bh;
+    int64_t ret;
+    QEMUIOVector *qiov;
+    char *bounce;
+    RBDAIOCmd cmd;
+    int error;
+    struct BDRVRBDState *s;
+} RBDAIOCB;
+
+typedef struct RADOSCB {
+    RBDAIOCB *acb;
+    struct BDRVRBDState *s;
+    int64_t size;
+    char *buf;
+    int64_t ret;
+} RADOSCB;
+
+typedef struct BDRVRBDState {
+    rados_t cluster;
+    rados_ioctx_t io_ctx;
+    rbd_image_t image;
+    char name[RBD_MAX_IMAGE_NAME_SIZE];
+    char *snap;
+} BDRVRBDState;
+
+static int qemu_rbd_next_tok(char *dst, int dst_len,
+                             char *src, char delim,
+                             const char *name,
+                             char **p, Error **errp)
+{
+    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_setg(errp, "%s too long", name);
+        return -EINVAL;
+    } else if (l == 0) {
+        error_setg(errp, "%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,
+                              Error **errp)
+{
+    const char *start;
+    char *p, *buf;
+    int ret;
+
+    if (!strstart(filename, "rbd:", &start)) {
+        error_setg(errp, "File name must start with 'rbd:'");
+        return -EINVAL;
+    }
+
+    buf = g_strdup(start);
+    p = buf;
+    *snap = '\0';
+    *conf = '\0';
+
+    ret = qemu_rbd_next_tok(pool, pool_len, p,
+                            '/', "pool name", &p, errp);
+    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, errp);
+        if (ret < 0) {
+            goto done;
+        }
+        ret = qemu_rbd_next_tok(snap, snap_len, p,
+                                ':', "snap name", &p, errp);
+        qemu_rbd_unescape(snap);
+    } else {
+        ret = qemu_rbd_next_tok(name, name_len, p,
+                                ':', "object name", &p, errp);
+    }
+    qemu_rbd_unescape(name);
+    if (ret < 0 || !p) {
+        goto done;
+    }
+
+    ret = qemu_rbd_next_tok(conf, conf_len, p,
+                            '\0', "configuration", &p, errp);
+
+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,
+                             bool only_read_conf_file,
+                             Error **errp)
+{
+    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, errp);
+        if (ret < 0) {
+            break;
+        }
+        qemu_rbd_unescape(name);
+
+        if (!p) {
+            error_setg(errp, "conf option %s has no value", name);
+            ret = -EINVAL;
+            break;
+        }
+
+        ret = qemu_rbd_next_tok(value, sizeof(value), p,
+                                ':', "conf option value", &p, errp);
+        if (ret < 0) {
+            break;
+        }
+        qemu_rbd_unescape(value);
+
+        if (strcmp(name, "conf") == 0) {
+            /* read the conf file alone, so it doesn't override more
+               specific settings for a particular device */
+            if (only_read_conf_file) {
+                ret = rados_conf_read_file(cluster, value);
+                if (ret < 0) {
+                    error_setg(errp, "error reading conf file %s", value);
+                    break;
+                }
+            }
+        } else if (strcmp(name, "id") == 0) {
+            /* ignore, this is parsed by qemu_rbd_parse_clientname() */
+        } else if (!only_read_conf_file) {
+            ret = rados_conf_set(cluster, name, value);
+            if (ret < 0) {
+                error_setg(errp, "invalid conf option %s", name);
+                ret = -EINVAL;
+                break;
+            }
+        }
+    }
+
+    g_free(buf);
+    return ret;
+}
+
+static int qemu_rbd_create(const char *filename, QemuOpts *opts, Error **errp)
+{
+    Error *local_err = NULL;
+    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), &local_err) < 0) {
+        error_propagate(errp, local_err);
+        return -EINVAL;
+    }
+
+    /* Read out options */
+    bytes = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
+                     BDRV_SECTOR_SIZE);
+    objsize = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 0);
+    if (objsize) {
+        if ((objsize - 1) & objsize) {    /* not a power of 2? */
+            error_setg(errp, "obj size needs to be power of 2");
+            return -EINVAL;
+        }
+        if (objsize < 4096) {
+            error_setg(errp, "obj size too small");
+            return -EINVAL;
+        }
+        obj_order = ctz32(objsize);
+    }
+
+    clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
+    if (rados_create(&cluster, clientname) < 0) {
+        error_setg(errp, "error initializing");
+        return -EIO;
+    }
+
+    if (strstr(conf, "conf=") == NULL) {
+        /* try default location, but ignore failure */
+        rados_conf_read_file(cluster, NULL);
+    } else if (conf[0] != '\0' &&
+               qemu_rbd_set_conf(cluster, conf, true, &local_err) < 0) {
+        rados_shutdown(cluster);
+        error_propagate(errp, local_err);
+        return -EIO;
+    }
+
+    if (conf[0] != '\0' &&
+        qemu_rbd_set_conf(cluster, conf, false, &local_err) < 0) {
+        rados_shutdown(cluster);
+        error_propagate(errp, local_err);
+        return -EIO;
+    }
+
+    if (rados_connect(cluster) < 0) {
+        error_setg(errp, "error connecting");
+        rados_shutdown(cluster);
+        return -EIO;
+    }
+
+    if (rados_ioctx_create(cluster, pool, &io_ctx) < 0) {
+        error_setg(errp, "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 rbd_finish_bh() and runs in qemu
+ * BH context.
+ */
+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;
+        }
+    }
+
+    g_free(rcb);
+
+    if (acb->cmd == RBD_AIO_READ) {
+        qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size);
+    }
+    qemu_vfree(acb->bounce);
+    acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
+
+    qemu_aio_unref(acb);
+}
+
+/* TODO Convert to fine grained options */
+static QemuOptsList runtime_opts = {
+    .name = "rbd",
+    .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
+    .desc = {
+        {
+            .name = "filename",
+            .type = QEMU_OPT_STRING,
+            .help = "Specification of the rbd image",
+        },
+        { /* end of list */ }
+    },
+};
+
+static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
+                         Error **errp)
+{
+    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;
+    QemuOpts *opts;
+    Error *local_err = NULL;
+    const char *filename;
+    int r;
+
+    opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
+    qemu_opts_absorb_qdict(opts, options, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        qemu_opts_del(opts);
+        return -EINVAL;
+    }
+
+    filename = qemu_opt_get(opts, "filename");
+
+    if (qemu_rbd_parsename(filename, pool, sizeof(pool),
+                           snap_buf, sizeof(snap_buf),
+                           s->name, sizeof(s->name),
+                           conf, sizeof(conf), errp) < 0) {
+        r = -EINVAL;
+        goto failed_opts;
+    }
+
+    clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
+    r = rados_create(&s->cluster, clientname);
+    if (r < 0) {
+        error_setg(errp, "error initializing");
+        goto failed_opts;
+    }
+
+    s->snap = NULL;
+    if (snap_buf[0] != '\0') {
+        s->snap = g_strdup(snap_buf);
+    }
+
+    if (strstr(conf, "conf=") == NULL) {
+        /* try default location, but ignore failure */
+        rados_conf_read_file(s->cluster, NULL);
+    } else if (conf[0] != '\0') {
+        r = qemu_rbd_set_conf(s->cluster, conf, true, errp);
+        if (r < 0) {
+            goto failed_shutdown;
+        }
+    }
+
+    if (conf[0] != '\0') {
+        r = qemu_rbd_set_conf(s->cluster, conf, false, errp);
+        if (r < 0) {
+            goto failed_shutdown;
+        }
+    }
+
+    /*
+     * 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");
+    }
+
+    r = rados_connect(s->cluster);
+    if (r < 0) {
+        error_setg(errp, "error connecting");
+        goto failed_shutdown;
+    }
+
+    r = rados_ioctx_create(s->cluster, pool, &s->io_ctx);
+    if (r < 0) {
+        error_setg(errp, "error opening pool %s", pool);
+        goto failed_shutdown;
+    }
+
+    r = rbd_open(s->io_ctx, s->name, &s->image, s->snap);
+    if (r < 0) {
+        error_setg(errp, "error reading header from %s", s->name);
+        goto failed_open;
+    }
+
+    bs->read_only = (s->snap != NULL);
+
+    qemu_opts_del(opts);
+    return 0;
+
+failed_open:
+    rados_ioctx_destroy(s->io_ctx);
+failed_shutdown:
+    rados_shutdown(s->cluster);
+    g_free(s->snap);
+failed_opts:
+    qemu_opts_del(opts);
+    return r;
+}
+
+static void qemu_rbd_close(BlockDriverState *bs)
+{
+    BDRVRBDState *s = bs->opaque;
+
+    rbd_close(s->image);
+    rados_ioctx_destroy(s->io_ctx);
+    g_free(s->snap);
+    rados_shutdown(s->cluster);
+}
+
+static const AIOCBInfo rbd_aiocb_info = {
+    .aiocb_size = sizeof(RBDAIOCB),
+};
+
+static void rbd_finish_bh(void *opaque)
+{
+    RADOSCB *rcb = opaque;
+    qemu_bh_delete(rcb->acb->bh);
+    qemu_rbd_complete_aio(rcb);
+}
+
+/*
+ * 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
+ * schedule a BH, and do the rest of the io completion handling
+ * from rbd_finish_bh() which runs in a qemu context.
+ */
+static void rbd_finish_aiocb(rbd_completion_t c, RADOSCB *rcb)
+{
+    RBDAIOCB *acb = rcb->acb;
+
+    rcb->ret = rbd_aio_get_return_value(c);
+    rbd_aio_release(c);
+
+    acb->bh = aio_bh_new(bdrv_get_aio_context(acb->common.bs),
+                         rbd_finish_bh, rcb);
+    qemu_bh_schedule(acb->bh);
+}
+
+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 BlockAIOCB *rbd_start_aio(BlockDriverState *bs,
+                                 int64_t sector_num,
+                                 QEMUIOVector *qiov,
+                                 int nb_sectors,
+                                 BlockCompletionFunc *cb,
+                                 void *opaque,
+                                 RBDAIOCmd cmd)
+{
+    RBDAIOCB *acb;
+    RADOSCB *rcb = NULL;
+    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_try_blockalign(bs, qiov->size);
+        if (acb->bounce == NULL) {
+            goto failed;
+        }
+    }
+    acb->ret = 0;
+    acb->error = 0;
+    acb->s = s;
+    acb->bh = NULL;
+
+    if (cmd == RBD_AIO_WRITE) {
+        qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size);
+    }
+
+    buf = acb->bounce;
+
+    off = sector_num * BDRV_SECTOR_SIZE;
+    size = nb_sectors * BDRV_SECTOR_SIZE;
+
+    rcb = g_new(RADOSCB, 1);
+    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_completion;
+    }
+
+    return &acb->common;
+
+failed_completion:
+    rbd_aio_release(c);
+failed:
+    g_free(rcb);
+    qemu_vfree(acb->bounce);
+    qemu_aio_unref(acb);
+    return NULL;
+}
+
+static BlockAIOCB *qemu_rbd_aio_readv(BlockDriverState *bs,
+                                      int64_t sector_num,
+                                      QEMUIOVector *qiov,
+                                      int nb_sectors,
+                                      BlockCompletionFunc *cb,
+                                      void *opaque)
+{
+    return rbd_start_aio(bs, sector_num, qiov, nb_sectors, cb, opaque,
+                         RBD_AIO_READ);
+}
+
+static BlockAIOCB *qemu_rbd_aio_writev(BlockDriverState *bs,
+                                       int64_t sector_num,
+                                       QEMUIOVector *qiov,
+                                       int nb_sectors,
+                                       BlockCompletionFunc *cb,
+                                       void *opaque)
+{
+    return rbd_start_aio(bs, sector_num, qiov, nb_sectors, cb, opaque,
+                         RBD_AIO_WRITE);
+}
+
+#ifdef LIBRBD_SUPPORTS_AIO_FLUSH
+static BlockAIOCB *qemu_rbd_aio_flush(BlockDriverState *bs,
+                                      BlockCompletionFunc *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_id,
+                                const char *snapshot_name,
+                                Error **errp)
+{
+    BDRVRBDState *s = bs->opaque;
+    int r;
+
+    if (!snapshot_name) {
+        error_setg(errp, "rbd need a valid snapshot name");
+        return -EINVAL;
+    }
+
+    /* If snapshot_id is specified, it must be equal to name, see
+       qemu_rbd_snap_list() */
+    if (snapshot_id && strcmp(snapshot_id, snapshot_name)) {
+        error_setg(errp,
+                   "rbd do not support snapshot id, it should be NULL or "
+                   "equal to snapshot name");
+        return -EINVAL;
+    }
+
+    r = rbd_snap_remove(s->image, snapshot_name);
+    if (r < 0) {
+        error_setg_errno(errp, -r, "Failed to remove the snapshot");
+    }
+    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_new(rbd_snap_info_t, 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_new0(QEMUSnapshotInfo, snap_count);
+
+    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);
+    g_free(snaps);
+
+ done:
+    *psn_tab = sn_tab;
+    return snap_count;
+}
+
+#ifdef LIBRBD_SUPPORTS_DISCARD
+static BlockAIOCB* qemu_rbd_aio_discard(BlockDriverState *bs,
+                                        int64_t sector_num,
+                                        int nb_sectors,
+                                        BlockCompletionFunc *cb,
+                                        void *opaque)
+{
+    return rbd_start_aio(bs, sector_num, NULL, nb_sectors, cb, opaque,
+                         RBD_AIO_DISCARD);
+}
+#endif
+
+#ifdef LIBRBD_SUPPORTS_INVALIDATE
+static void qemu_rbd_invalidate_cache(BlockDriverState *bs,
+                                      Error **errp)
+{
+    BDRVRBDState *s = bs->opaque;
+    int r = rbd_invalidate_cache(s->image);
+    if (r < 0) {
+        error_setg_errno(errp, -r, "Failed to invalidate the cache");
+    }
+}
+#endif
+
+static QemuOptsList qemu_rbd_create_opts = {
+    .name = "rbd-create-opts",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_rbd_create_opts.head),
+    .desc = {
+        {
+            .name = BLOCK_OPT_SIZE,
+            .type = QEMU_OPT_SIZE,
+            .help = "Virtual disk size"
+        },
+        {
+            .name = BLOCK_OPT_CLUSTER_SIZE,
+            .type = QEMU_OPT_SIZE,
+            .help = "RBD object size"
+        },
+        { /* end of list */ }
+    }
+};
+
+static BlockDriver bdrv_rbd = {
+    .format_name        = "rbd",
+    .instance_size      = sizeof(BDRVRBDState),
+    .bdrv_needs_filename = true,
+    .bdrv_file_open     = qemu_rbd_open,
+    .bdrv_close         = qemu_rbd_close,
+    .bdrv_create        = qemu_rbd_create,
+    .bdrv_has_zero_init = bdrv_has_zero_init_1,
+    .bdrv_get_info      = qemu_rbd_getinfo,
+    .create_opts        = &qemu_rbd_create_opts,
+    .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_to_disk  = 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,
+#ifdef LIBRBD_SUPPORTS_INVALIDATE
+    .bdrv_invalidate_cache  = qemu_rbd_invalidate_cache,
+#endif
+};
+
+static void bdrv_rbd_init(void)
+{
+    bdrv_register(&bdrv_rbd);
+}
+
+block_init(bdrv_rbd_init);