qemu

gluster.c (52671B)

---

 /*
  * GlusterFS backend for QEMU
  *
  * Copyright (C) 2012 Bharata B Rao <bharata@linux.vnet.ibm.com>
  *
  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  * See the COPYING file in the top-level directory.
  *
  */
 
 #include "qemu/osdep.h"
 #include "qemu/units.h"
 #include <glusterfs/api/glfs.h>
 #include "block/block_int.h"
 #include "block/qdict.h"
 #include "qapi/error.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qerror.h"
 #include "qemu/uri.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
 #include "qemu/cutils.h"
 
 #ifdef CONFIG_GLUSTERFS_FTRUNCATE_HAS_STAT
 # define glfs_ftruncate(fd, offset) glfs_ftruncate(fd, offset, NULL, NULL)
 #endif
 
 #define GLUSTER_OPT_FILENAME        "filename"
 #define GLUSTER_OPT_VOLUME          "volume"
 #define GLUSTER_OPT_PATH            "path"
 #define GLUSTER_OPT_TYPE            "type"
 #define GLUSTER_OPT_SERVER_PATTERN  "server."
 #define GLUSTER_OPT_HOST            "host"
 #define GLUSTER_OPT_PORT            "port"
 #define GLUSTER_OPT_TO              "to"
 #define GLUSTER_OPT_IPV4            "ipv4"
 #define GLUSTER_OPT_IPV6            "ipv6"
 #define GLUSTER_OPT_SOCKET          "socket"
 #define GLUSTER_OPT_DEBUG           "debug"
 #define GLUSTER_DEFAULT_PORT        24007
 #define GLUSTER_DEBUG_DEFAULT       4
 #define GLUSTER_DEBUG_MAX           9
 #define GLUSTER_OPT_LOGFILE         "logfile"
 #define GLUSTER_LOGFILE_DEFAULT     "-" /* handled in libgfapi as /dev/stderr */
 /*
  * Several versions of GlusterFS (3.12? -> 6.0.1) fail when the transfer size
  * is greater or equal to 1024 MiB, so we are limiting the transfer size to 512
  * MiB to avoid this rare issue.
  */
 #define GLUSTER_MAX_TRANSFER        (512 * MiB)
 
 #define GERR_INDEX_HINT "hint: check in 'server' array index '%d'\n"
 
 typedef struct GlusterAIOCB {
     int64_t size;
     int ret;
     Coroutine *coroutine;
     AioContext *aio_context;
 } GlusterAIOCB;
 
 typedef struct BDRVGlusterState {
     struct glfs *glfs;
     struct glfs_fd *fd;
     char *logfile;
     bool supports_seek_data;
     int debug;
 } BDRVGlusterState;
 
 typedef struct BDRVGlusterReopenState {
     struct glfs *glfs;
     struct glfs_fd *fd;
 } BDRVGlusterReopenState;
 
 
 typedef struct GlfsPreopened {
     char *volume;
     glfs_t *fs;
     int ref;
 } GlfsPreopened;
 
 typedef struct ListElement {
     QLIST_ENTRY(ListElement) list;
     GlfsPreopened saved;
 } ListElement;
 
 static QLIST_HEAD(, ListElement) glfs_list;
 
 static QemuOptsList qemu_gluster_create_opts = {
     .name = "qemu-gluster-create-opts",
     .head = QTAILQ_HEAD_INITIALIZER(qemu_gluster_create_opts.head),
     .desc = {
         {
             .name = BLOCK_OPT_SIZE,
             .type = QEMU_OPT_SIZE,
             .help = "Virtual disk size"
         },
         {
             .name = BLOCK_OPT_PREALLOC,
             .type = QEMU_OPT_STRING,
             .help = "Preallocation mode (allowed values: off"
 #ifdef CONFIG_GLUSTERFS_FALLOCATE
                     ", falloc"
 #endif
 #ifdef CONFIG_GLUSTERFS_ZEROFILL
                     ", full"
 #endif
                     ")"
         },
         {
             .name = GLUSTER_OPT_DEBUG,
             .type = QEMU_OPT_NUMBER,
             .help = "Gluster log level, valid range is 0-9",
         },
         {
             .name = GLUSTER_OPT_LOGFILE,
             .type = QEMU_OPT_STRING,
             .help = "Logfile path of libgfapi",
         },
         { /* end of list */ }
     }
 };
 
 static QemuOptsList runtime_opts = {
     .name = "gluster",
     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
     .desc = {
         {
             .name = GLUSTER_OPT_FILENAME,
             .type = QEMU_OPT_STRING,
             .help = "URL to the gluster image",
         },
         {
             .name = GLUSTER_OPT_DEBUG,
             .type = QEMU_OPT_NUMBER,
             .help = "Gluster log level, valid range is 0-9",
         },
         {
             .name = GLUSTER_OPT_LOGFILE,
             .type = QEMU_OPT_STRING,
             .help = "Logfile path of libgfapi",
         },
         { /* end of list */ }
     },
 };
 
 static QemuOptsList runtime_json_opts = {
     .name = "gluster_json",
     .head = QTAILQ_HEAD_INITIALIZER(runtime_json_opts.head),
     .desc = {
         {
             .name = GLUSTER_OPT_VOLUME,
             .type = QEMU_OPT_STRING,
             .help = "name of gluster volume where VM image resides",
         },
         {
             .name = GLUSTER_OPT_PATH,
             .type = QEMU_OPT_STRING,
             .help = "absolute path to image file in gluster volume",
         },
         {
             .name = GLUSTER_OPT_DEBUG,
             .type = QEMU_OPT_NUMBER,
             .help = "Gluster log level, valid range is 0-9",
         },
         { /* end of list */ }
     },
 };
 
 static QemuOptsList runtime_type_opts = {
     .name = "gluster_type",
     .head = QTAILQ_HEAD_INITIALIZER(runtime_type_opts.head),
     .desc = {
         {
             .name = GLUSTER_OPT_TYPE,
             .type = QEMU_OPT_STRING,
             .help = "inet|unix",
         },
         { /* end of list */ }
     },
 };
 
 static QemuOptsList runtime_unix_opts = {
     .name = "gluster_unix",
     .head = QTAILQ_HEAD_INITIALIZER(runtime_unix_opts.head),
     .desc = {
         {
             .name = GLUSTER_OPT_SOCKET,
             .type = QEMU_OPT_STRING,
             .help = "socket file path (legacy)",
         },
         {
             .name = GLUSTER_OPT_PATH,
             .type = QEMU_OPT_STRING,
             .help = "socket file path (QAPI)",
         },
         { /* end of list */ }
     },
 };
 
 static QemuOptsList runtime_inet_opts = {
     .name = "gluster_inet",
     .head = QTAILQ_HEAD_INITIALIZER(runtime_inet_opts.head),
     .desc = {
         {
             .name = GLUSTER_OPT_TYPE,
             .type = QEMU_OPT_STRING,
             .help = "inet|unix",
         },
         {
             .name = GLUSTER_OPT_HOST,
             .type = QEMU_OPT_STRING,
             .help = "host address (hostname/ipv4/ipv6 addresses)",
         },
         {
             .name = GLUSTER_OPT_PORT,
             .type = QEMU_OPT_STRING,
             .help = "port number on which glusterd is listening (default 24007)",
         },
         {
             .name = "to",
             .type = QEMU_OPT_NUMBER,
             .help = "max port number, not supported by gluster",
         },
         {
             .name = "ipv4",
             .type = QEMU_OPT_BOOL,
             .help = "ipv4 bool value, not supported by gluster",
         },
         {
             .name = "ipv6",
             .type = QEMU_OPT_BOOL,
             .help = "ipv6 bool value, not supported by gluster",
         },
         { /* end of list */ }
     },
 };
 
 static void glfs_set_preopened(const char *volume, glfs_t *fs)
 {
     ListElement *entry = NULL;
 
     entry = g_new(ListElement, 1);
 
     entry->saved.volume = g_strdup(volume);
 
     entry->saved.fs = fs;
     entry->saved.ref = 1;
 
     QLIST_INSERT_HEAD(&glfs_list, entry, list);
 }
 
 static glfs_t *glfs_find_preopened(const char *volume)
 {
     ListElement *entry = NULL;
 
      QLIST_FOREACH(entry, &glfs_list, list) {
         if (strcmp(entry->saved.volume, volume) == 0) {
             entry->saved.ref++;
             return entry->saved.fs;
         }
      }
 
     return NULL;
 }
 
 static void glfs_clear_preopened(glfs_t *fs)
 {
     ListElement *entry = NULL;
     ListElement *next;
 
     if (fs == NULL) {
         return;
     }
 
     QLIST_FOREACH_SAFE(entry, &glfs_list, list, next) {
         if (entry->saved.fs == fs) {
             if (--entry->saved.ref) {
                 return;
             }
 
             QLIST_REMOVE(entry, list);
 
             glfs_fini(entry->saved.fs);
             g_free(entry->saved.volume);
             g_free(entry);
         }
     }
 }
 
 static int parse_volume_options(BlockdevOptionsGluster *gconf, char *path)
 {
     char *p, *q;
 
     if (!path) {
         return -EINVAL;
     }
 
     /* volume */
     p = q = path + strspn(path, "/");
     p += strcspn(p, "/");
     if (*p == '\0') {
         return -EINVAL;
     }
     gconf->volume = g_strndup(q, p - q);
 
     /* path */
     p += strspn(p, "/");
     if (*p == '\0') {
         return -EINVAL;
     }
     gconf->path = g_strdup(p);
     return 0;
 }
 
 /*
  * file=gluster[+transport]://[host[:port]]/volume/path[?socket=...]
  *
  * 'gluster' is the protocol.
  *
  * 'transport' specifies the transport type used to connect to gluster
  * management daemon (glusterd). Valid transport types are
  * tcp or unix. If a transport type isn't specified, then tcp type is assumed.
  *
  * 'host' specifies the host where the volume file specification for
  * the given volume resides. This can be either hostname or ipv4 address.
  * If transport type is 'unix', then 'host' field should not be specified.
  * The 'socket' field needs to be populated with the path to unix domain
  * socket.
  *
  * 'port' is the port number on which glusterd is listening. This is optional
  * and if not specified, QEMU will send 0 which will make gluster to use the
  * default port. If the transport type is unix, then 'port' should not be
  * specified.
  *
  * 'volume' is the name of the gluster volume which contains the VM image.
  *
  * 'path' is the path to the actual VM image that resides on gluster volume.
  *
  * Examples:
  *
  * file=gluster://1.2.3.4/testvol/a.img
  * file=gluster+tcp://1.2.3.4/testvol/a.img
  * file=gluster+tcp://1.2.3.4:24007/testvol/dir/a.img
  * file=gluster+tcp://host.domain.com:24007/testvol/dir/a.img
  * file=gluster+unix:///testvol/dir/a.img?socket=/tmp/glusterd.socket
  */
 static int qemu_gluster_parse_uri(BlockdevOptionsGluster *gconf,
                                   const char *filename)
 {
     SocketAddress *gsconf;
     URI *uri;
     QueryParams *qp = NULL;
     bool is_unix = false;
     int ret = 0;
 
     uri = uri_parse(filename);
     if (!uri) {
         return -EINVAL;
     }
 
     gsconf = g_new0(SocketAddress, 1);
     QAPI_LIST_PREPEND(gconf->server, gsconf);
 
     /* transport */
     if (!uri->scheme || !strcmp(uri->scheme, "gluster")) {
         gsconf->type = SOCKET_ADDRESS_TYPE_INET;
     } else if (!strcmp(uri->scheme, "gluster+tcp")) {
         gsconf->type = SOCKET_ADDRESS_TYPE_INET;
     } else if (!strcmp(uri->scheme, "gluster+unix")) {
         gsconf->type = SOCKET_ADDRESS_TYPE_UNIX;
         is_unix = true;
     } else if (!strcmp(uri->scheme, "gluster+rdma")) {
         gsconf->type = SOCKET_ADDRESS_TYPE_INET;
         warn_report("rdma feature is not supported, falling back to tcp");
     } else {
         ret = -EINVAL;
         goto out;
     }
 
     ret = parse_volume_options(gconf, uri->path);
     if (ret < 0) {
         goto out;
     }
 
     qp = query_params_parse(uri->query);
     if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
         ret = -EINVAL;
         goto out;
     }
 
     if (is_unix) {
         if (uri->server || uri->port) {
             ret = -EINVAL;
             goto out;
         }
         if (strcmp(qp->p[0].name, "socket")) {
             ret = -EINVAL;
             goto out;
         }
         gsconf->u.q_unix.path = g_strdup(qp->p[0].value);
     } else {
         gsconf->u.inet.host = g_strdup(uri->server ? uri->server : "localhost");
         if (uri->port) {
             gsconf->u.inet.port = g_strdup_printf("%d", uri->port);
         } else {
             gsconf->u.inet.port = g_strdup_printf("%d", GLUSTER_DEFAULT_PORT);
         }
     }
 
 out:
     if (qp) {
         query_params_free(qp);
     }
     uri_free(uri);
     return ret;
 }
 
 static struct glfs *qemu_gluster_glfs_init(BlockdevOptionsGluster *gconf,
                                            Error **errp)
 {
     struct glfs *glfs;
     int ret;
     int old_errno;
     SocketAddressList *server;
     unsigned long long port;
 
     glfs = glfs_find_preopened(gconf->volume);
     if (glfs) {
         return glfs;
     }
 
     glfs = glfs_new(gconf->volume);
     if (!glfs) {
         goto out;
     }
 
     glfs_set_preopened(gconf->volume, glfs);
 
     for (server = gconf->server; server; server = server->next) {
         switch (server->value->type) {
         case SOCKET_ADDRESS_TYPE_UNIX:
             ret = glfs_set_volfile_server(glfs, "unix",
                                    server->value->u.q_unix.path, 0);
             break;
         case SOCKET_ADDRESS_TYPE_INET:
             if (parse_uint_full(server->value->u.inet.port, &port, 10) < 0 ||
                 port > 65535) {
                 error_setg(errp, "'%s' is not a valid port number",
                            server->value->u.inet.port);
                 errno = EINVAL;
                 goto out;
             }
             ret = glfs_set_volfile_server(glfs, "tcp",
                                    server->value->u.inet.host,
                                    (int)port);
             break;
         case SOCKET_ADDRESS_TYPE_VSOCK:
         case SOCKET_ADDRESS_TYPE_FD:
         default:
             abort();
         }
 
         if (ret < 0) {
             goto out;
         }
     }
 
     ret = glfs_set_logging(glfs, gconf->logfile, gconf->debug);
     if (ret < 0) {
         goto out;
     }
 
     ret = glfs_init(glfs);
     if (ret) {
         error_setg(errp, "Gluster connection for volume %s, path %s failed"
                          " to connect", gconf->volume, gconf->path);
         for (server = gconf->server; server; server = server->next) {
             if (server->value->type  == SOCKET_ADDRESS_TYPE_UNIX) {
                 error_append_hint(errp, "hint: failed on socket %s ",
                                   server->value->u.q_unix.path);
             } else {
                 error_append_hint(errp, "hint: failed on host %s and port %s ",
                                   server->value->u.inet.host,
                                   server->value->u.inet.port);
             }
         }
 
         error_append_hint(errp, "Please refer to gluster logs for more info\n");
 
         /* glfs_init sometimes doesn't set errno although docs suggest that */
         if (errno == 0) {
             errno = EINVAL;
         }
 
         goto out;
     }
     return glfs;
 
 out:
     if (glfs) {
         old_errno = errno;
         glfs_clear_preopened(glfs);
         errno = old_errno;
     }
     return NULL;
 }
 
 /*
  * Convert the json formatted command line into qapi.
 */
 static int qemu_gluster_parse_json(BlockdevOptionsGluster *gconf,
                                   QDict *options, Error **errp)
 {
     QemuOpts *opts;
     SocketAddress *gsconf = NULL;
     SocketAddressList **tail;
     QDict *backing_options = NULL;
     Error *local_err = NULL;
     char *str = NULL;
     const char *ptr;
     int i, type, num_servers;
 
     /* create opts info from runtime_json_opts list */
     opts = qemu_opts_create(&runtime_json_opts, NULL, 0, &error_abort);
     if (!qemu_opts_absorb_qdict(opts, options, errp)) {
         goto out;
     }
 
     num_servers = qdict_array_entries(options, GLUSTER_OPT_SERVER_PATTERN);
     if (num_servers < 1) {
         error_setg(&local_err, QERR_MISSING_PARAMETER, "server");
         goto out;
     }
 
     ptr = qemu_opt_get(opts, GLUSTER_OPT_VOLUME);
     if (!ptr) {
         error_setg(&local_err, QERR_MISSING_PARAMETER, GLUSTER_OPT_VOLUME);
         goto out;
     }
     gconf->volume = g_strdup(ptr);
 
     ptr = qemu_opt_get(opts, GLUSTER_OPT_PATH);
     if (!ptr) {
         error_setg(&local_err, QERR_MISSING_PARAMETER, GLUSTER_OPT_PATH);
         goto out;
     }
     gconf->path = g_strdup(ptr);
     qemu_opts_del(opts);
     tail = &gconf->server;
 
     for (i = 0; i < num_servers; i++) {
         str = g_strdup_printf(GLUSTER_OPT_SERVER_PATTERN"%d.", i);
         qdict_extract_subqdict(options, &backing_options, str);
 
         /* create opts info from runtime_type_opts list */
         opts = qemu_opts_create(&runtime_type_opts, NULL, 0, &error_abort);
         if (!qemu_opts_absorb_qdict(opts, backing_options, errp)) {
             goto out;
         }
 
         ptr = qemu_opt_get(opts, GLUSTER_OPT_TYPE);
         if (!ptr) {
             error_setg(&local_err, QERR_MISSING_PARAMETER, GLUSTER_OPT_TYPE);
             error_append_hint(&local_err, GERR_INDEX_HINT, i);
             goto out;
 
         }
         gsconf = g_new0(SocketAddress, 1);
         if (!strcmp(ptr, "tcp")) {
             ptr = "inet";       /* accept legacy "tcp" */
         }
         type = qapi_enum_parse(&SocketAddressType_lookup, ptr, -1, NULL);
         if (type != SOCKET_ADDRESS_TYPE_INET
             && type != SOCKET_ADDRESS_TYPE_UNIX) {
             error_setg(&local_err,
                        "Parameter '%s' may be 'inet' or 'unix'",
                        GLUSTER_OPT_TYPE);
             error_append_hint(&local_err, GERR_INDEX_HINT, i);
             goto out;
         }
         gsconf->type = type;
         qemu_opts_del(opts);
 
         if (gsconf->type == SOCKET_ADDRESS_TYPE_INET) {
             /* create opts info from runtime_inet_opts list */
             opts = qemu_opts_create(&runtime_inet_opts, NULL, 0, &error_abort);
             if (!qemu_opts_absorb_qdict(opts, backing_options, errp)) {
                 goto out;
             }
 
             ptr = qemu_opt_get(opts, GLUSTER_OPT_HOST);
             if (!ptr) {
                 error_setg(&local_err, QERR_MISSING_PARAMETER,
                            GLUSTER_OPT_HOST);
                 error_append_hint(&local_err, GERR_INDEX_HINT, i);
                 goto out;
             }
             gsconf->u.inet.host = g_strdup(ptr);
             ptr = qemu_opt_get(opts, GLUSTER_OPT_PORT);
             if (!ptr) {
                 error_setg(&local_err, QERR_MISSING_PARAMETER,
                            GLUSTER_OPT_PORT);
                 error_append_hint(&local_err, GERR_INDEX_HINT, i);
                 goto out;
             }
             gsconf->u.inet.port = g_strdup(ptr);
 
             /* defend for unsupported fields in InetSocketAddress,
              * i.e. @ipv4, @ipv6  and @to
              */
             ptr = qemu_opt_get(opts, GLUSTER_OPT_TO);
             if (ptr) {
                 gsconf->u.inet.has_to = true;
             }
             ptr = qemu_opt_get(opts, GLUSTER_OPT_IPV4);
             if (ptr) {
                 gsconf->u.inet.has_ipv4 = true;
             }
             ptr = qemu_opt_get(opts, GLUSTER_OPT_IPV6);
             if (ptr) {
                 gsconf->u.inet.has_ipv6 = true;
             }
             if (gsconf->u.inet.has_to) {
                 error_setg(&local_err, "Parameter 'to' not supported");
                 goto out;
             }
             if (gsconf->u.inet.has_ipv4 || gsconf->u.inet.has_ipv6) {
                 error_setg(&local_err, "Parameters 'ipv4/ipv6' not supported");
                 goto out;
             }
             qemu_opts_del(opts);
         } else {
             /* create opts info from runtime_unix_opts list */
             opts = qemu_opts_create(&runtime_unix_opts, NULL, 0, &error_abort);
             if (!qemu_opts_absorb_qdict(opts, backing_options, errp)) {
                 goto out;
             }
 
             ptr = qemu_opt_get(opts, GLUSTER_OPT_PATH);
             if (!ptr) {
                 ptr = qemu_opt_get(opts, GLUSTER_OPT_SOCKET);
             } else if (qemu_opt_get(opts, GLUSTER_OPT_SOCKET)) {
                 error_setg(&local_err,
                            "Conflicting parameters 'path' and 'socket'");
                 error_append_hint(&local_err, GERR_INDEX_HINT, i);
                 goto out;
             }
             if (!ptr) {
                 error_setg(&local_err, QERR_MISSING_PARAMETER,
                            GLUSTER_OPT_PATH);
                 error_append_hint(&local_err, GERR_INDEX_HINT, i);
                 goto out;
             }
             gsconf->u.q_unix.path = g_strdup(ptr);
             qemu_opts_del(opts);
         }
 
         QAPI_LIST_APPEND(tail, gsconf);
         gsconf = NULL;
 
         qobject_unref(backing_options);
         backing_options = NULL;
         g_free(str);
         str = NULL;
     }
 
     return 0;
 
 out:
     error_propagate(errp, local_err);
     qapi_free_SocketAddress(gsconf);
     qemu_opts_del(opts);
     g_free(str);
     qobject_unref(backing_options);
     errno = EINVAL;
     return -errno;
 }
 
 /* Converts options given in @filename and the @options QDict into the QAPI
  * object @gconf. */
 static int qemu_gluster_parse(BlockdevOptionsGluster *gconf,
                               const char *filename,
                               QDict *options, Error **errp)
 {
     int ret;
     if (filename) {
         ret = qemu_gluster_parse_uri(gconf, filename);
         if (ret < 0) {
             error_setg(errp, "invalid URI %s", filename);
             error_append_hint(errp, "Usage: file=gluster[+transport]://"
                                     "[host[:port]]volume/path[?socket=...]"
                                     "[,file.debug=N]"
                                     "[,file.logfile=/path/filename.log]\n");
             return ret;
         }
     } else {
         ret = qemu_gluster_parse_json(gconf, options, errp);
         if (ret < 0) {
             error_append_hint(errp, "Usage: "
                              "-drive driver=qcow2,file.driver=gluster,"
                              "file.volume=testvol,file.path=/path/a.qcow2"
                              "[,file.debug=9]"
                              "[,file.logfile=/path/filename.log],"
                              "file.server.0.type=inet,"
                              "file.server.0.host=1.2.3.4,"
                              "file.server.0.port=24007,"
                              "file.server.1.transport=unix,"
                              "file.server.1.path=/var/run/glusterd.socket ..."
                              "\n");
             return ret;
         }
     }
 
     return 0;
 }
 
 static struct glfs *qemu_gluster_init(BlockdevOptionsGluster *gconf,
                                       const char *filename,
                                       QDict *options, Error **errp)
 {
     int ret;
 
     ret = qemu_gluster_parse(gconf, filename, options, errp);
     if (ret < 0) {
         errno = -ret;
         return NULL;
     }
 
     return qemu_gluster_glfs_init(gconf, errp);
 }
 
 /*
  * AIO callback routine called from GlusterFS thread.
  */
 static void gluster_finish_aiocb(struct glfs_fd *fd, ssize_t ret,
 #ifdef CONFIG_GLUSTERFS_IOCB_HAS_STAT
                                  struct glfs_stat *pre, struct glfs_stat *post,
 #endif
                                  void *arg)
 {
     GlusterAIOCB *acb = (GlusterAIOCB *)arg;
 
     if (!ret || ret == acb->size) {
         acb->ret = 0; /* Success */
     } else if (ret < 0) {
         acb->ret = -errno; /* Read/Write failed */
     } else {
         acb->ret = -EIO; /* Partial read/write - fail it */
     }
 
     aio_co_schedule(acb->aio_context, acb->coroutine);
 }
 
 static void qemu_gluster_parse_flags(int bdrv_flags, int *open_flags)
 {
     assert(open_flags != NULL);
 
     *open_flags |= O_BINARY;
 
     if (bdrv_flags & BDRV_O_RDWR) {
         *open_flags |= O_RDWR;
     } else {
         *open_flags |= O_RDONLY;
     }
 
     if ((bdrv_flags & BDRV_O_NOCACHE)) {
         *open_flags |= O_DIRECT;
     }
 }
 
 /*
  * Do SEEK_DATA/HOLE to detect if it is functional. Older broken versions of
  * gfapi incorrectly return the current offset when SEEK_DATA/HOLE is used.
  * - Corrected versions return -1 and set errno to EINVAL.
  * - Versions that support SEEK_DATA/HOLE correctly, will return -1 and set
  *   errno to ENXIO when SEEK_DATA is called with a position of EOF.
  */
 static bool qemu_gluster_test_seek(struct glfs_fd *fd)
 {
     off_t ret = 0;
 
 #if defined SEEK_HOLE && defined SEEK_DATA
     off_t eof;
 
     eof = glfs_lseek(fd, 0, SEEK_END);
     if (eof < 0) {
         /* this should never occur */
         return false;
     }
 
     /* this should always fail with ENXIO if SEEK_DATA is supported */
     ret = glfs_lseek(fd, eof, SEEK_DATA);
 #endif
 
     return (ret < 0) && (errno == ENXIO);
 }
 
 static int qemu_gluster_open(BlockDriverState *bs,  QDict *options,
                              int bdrv_flags, Error **errp)
 {
     BDRVGlusterState *s = bs->opaque;
     int open_flags = 0;
     int ret = 0;
     BlockdevOptionsGluster *gconf = NULL;
     QemuOpts *opts;
     const char *filename, *logfile;
 
     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
     if (!qemu_opts_absorb_qdict(opts, options, errp)) {
         ret = -EINVAL;
         goto out;
     }
 
     filename = qemu_opt_get(opts, GLUSTER_OPT_FILENAME);
 
     s->debug = qemu_opt_get_number(opts, GLUSTER_OPT_DEBUG,
                                    GLUSTER_DEBUG_DEFAULT);
     if (s->debug < 0) {
         s->debug = 0;
     } else if (s->debug > GLUSTER_DEBUG_MAX) {
         s->debug = GLUSTER_DEBUG_MAX;
     }
 
     gconf = g_new0(BlockdevOptionsGluster, 1);
     gconf->debug = s->debug;
     gconf->has_debug = true;
 
     logfile = qemu_opt_get(opts, GLUSTER_OPT_LOGFILE);
     s->logfile = g_strdup(logfile ? logfile : GLUSTER_LOGFILE_DEFAULT);
 
     gconf->logfile = g_strdup(s->logfile);
     gconf->has_logfile = true;
 
     s->glfs = qemu_gluster_init(gconf, filename, options, errp);
     if (!s->glfs) {
         ret = -errno;
         goto out;
     }
 
 #ifdef CONFIG_GLUSTERFS_XLATOR_OPT
     /* Without this, if fsync fails for a recoverable reason (for instance,
      * ENOSPC), gluster will dump its cache, preventing retries.  This means
      * almost certain data loss.  Not all gluster versions support the
      * 'resync-failed-syncs-after-fsync' key value, but there is no way to
      * discover during runtime if it is supported (this api returns success for
      * unknown key/value pairs) */
     ret = glfs_set_xlator_option(s->glfs, "*-write-behind",
                                           "resync-failed-syncs-after-fsync",
                                           "on");
     if (ret < 0) {
         error_setg_errno(errp, errno, "Unable to set xlator key/value pair");
         ret = -errno;
         goto out;
     }
 #endif
 
     qemu_gluster_parse_flags(bdrv_flags, &open_flags);
 
     s->fd = glfs_open(s->glfs, gconf->path, open_flags);
     ret = s->fd ? 0 : -errno;
 
     if (ret == -EACCES || ret == -EROFS) {
         /* Try to degrade to read-only, but if it doesn't work, still use the
          * normal error message. */
         if (bdrv_apply_auto_read_only(bs, NULL, NULL) == 0) {
             open_flags = (open_flags & ~O_RDWR) | O_RDONLY;
             s->fd = glfs_open(s->glfs, gconf->path, open_flags);
             ret = s->fd ? 0 : -errno;
         }
     }
 
     s->supports_seek_data = qemu_gluster_test_seek(s->fd);
 
 out:
     qemu_opts_del(opts);
     qapi_free_BlockdevOptionsGluster(gconf);
     if (!ret) {
         return ret;
     }
     g_free(s->logfile);
     if (s->fd) {
         glfs_close(s->fd);
     }
 
     glfs_clear_preopened(s->glfs);
 
     return ret;
 }
 
 static void qemu_gluster_refresh_limits(BlockDriverState *bs, Error **errp)
 {
     bs->bl.max_transfer = GLUSTER_MAX_TRANSFER;
     bs->bl.max_pdiscard = MIN(SIZE_MAX, INT64_MAX);
 }
 
 static int qemu_gluster_reopen_prepare(BDRVReopenState *state,
                                        BlockReopenQueue *queue, Error **errp)
 {
     int ret = 0;
     BDRVGlusterState *s;
     BDRVGlusterReopenState *reop_s;
     BlockdevOptionsGluster *gconf;
     int open_flags = 0;
 
     assert(state != NULL);
     assert(state->bs != NULL);
 
     s = state->bs->opaque;
 
     state->opaque = g_new0(BDRVGlusterReopenState, 1);
     reop_s = state->opaque;
 
     qemu_gluster_parse_flags(state->flags, &open_flags);
 
     gconf = g_new0(BlockdevOptionsGluster, 1);
     gconf->debug = s->debug;
     gconf->has_debug = true;
     gconf->logfile = g_strdup(s->logfile);
     gconf->has_logfile = true;
 
     /*
      * If 'state->bs->exact_filename' is empty, 'state->options' should contain
      * the JSON parameters already parsed.
      */
     if (state->bs->exact_filename[0] != '\0') {
         reop_s->glfs = qemu_gluster_init(gconf, state->bs->exact_filename, NULL,
                                          errp);
     } else {
         reop_s->glfs = qemu_gluster_init(gconf, NULL, state->options, errp);
     }
     if (reop_s->glfs == NULL) {
         ret = -errno;
         goto exit;
     }
 
 #ifdef CONFIG_GLUSTERFS_XLATOR_OPT
     ret = glfs_set_xlator_option(reop_s->glfs, "*-write-behind",
                                  "resync-failed-syncs-after-fsync", "on");
     if (ret < 0) {
         error_setg_errno(errp, errno, "Unable to set xlator key/value pair");
         ret = -errno;
         goto exit;
     }
 #endif
 
     reop_s->fd = glfs_open(reop_s->glfs, gconf->path, open_flags);
     if (reop_s->fd == NULL) {
         /* reops->glfs will be cleaned up in _abort */
         ret = -errno;
         goto exit;
     }
 
 exit:
     /* state->opaque will be freed in either the _abort or _commit */
     qapi_free_BlockdevOptionsGluster(gconf);
     return ret;
 }
 
 static void qemu_gluster_reopen_commit(BDRVReopenState *state)
 {
     BDRVGlusterReopenState *reop_s = state->opaque;
     BDRVGlusterState *s = state->bs->opaque;
 
 
     /* close the old */
     if (s->fd) {
         glfs_close(s->fd);
     }
 
     glfs_clear_preopened(s->glfs);
 
     /* use the newly opened image / connection */
     s->fd         = reop_s->fd;
     s->glfs       = reop_s->glfs;
 
     g_free(state->opaque);
     state->opaque = NULL;
 
     return;
 }
 
 
 static void qemu_gluster_reopen_abort(BDRVReopenState *state)
 {
     BDRVGlusterReopenState *reop_s = state->opaque;
 
     if (reop_s == NULL) {
         return;
     }
 
     if (reop_s->fd) {
         glfs_close(reop_s->fd);
     }
 
     glfs_clear_preopened(reop_s->glfs);
 
     g_free(state->opaque);
     state->opaque = NULL;
 
     return;
 }
 
 #ifdef CONFIG_GLUSTERFS_ZEROFILL
 static coroutine_fn int qemu_gluster_co_pwrite_zeroes(BlockDriverState *bs,
                                                       int64_t offset,
                                                       int64_t bytes,
                                                       BdrvRequestFlags flags)
 {
     int ret;
     GlusterAIOCB acb;
     BDRVGlusterState *s = bs->opaque;
 
     acb.size = bytes;
     acb.ret = 0;
     acb.coroutine = qemu_coroutine_self();
     acb.aio_context = bdrv_get_aio_context(bs);
 
     ret = glfs_zerofill_async(s->fd, offset, bytes, gluster_finish_aiocb, &acb);
     if (ret < 0) {
         return -errno;
     }
 
     qemu_coroutine_yield();
     return acb.ret;
 }
 #endif
 
 static int qemu_gluster_do_truncate(struct glfs_fd *fd, int64_t offset,
                                     PreallocMode prealloc, Error **errp)
 {
     int64_t current_length;
 
     current_length = glfs_lseek(fd, 0, SEEK_END);
     if (current_length < 0) {
         error_setg_errno(errp, errno, "Failed to determine current size");
         return -errno;
     }
 
     if (current_length > offset && prealloc != PREALLOC_MODE_OFF) {
         error_setg(errp, "Cannot use preallocation for shrinking files");
         return -ENOTSUP;
     }
 
     if (current_length == offset) {
         return 0;
     }
 
     switch (prealloc) {
 #ifdef CONFIG_GLUSTERFS_FALLOCATE
     case PREALLOC_MODE_FALLOC:
         if (glfs_fallocate(fd, 0, current_length, offset - current_length)) {
             error_setg_errno(errp, errno, "Could not preallocate data");
             return -errno;
         }
         break;
 #endif /* CONFIG_GLUSTERFS_FALLOCATE */
 #ifdef CONFIG_GLUSTERFS_ZEROFILL
     case PREALLOC_MODE_FULL:
         if (glfs_ftruncate(fd, offset)) {
             error_setg_errno(errp, errno, "Could not resize file");
             return -errno;
         }
         if (glfs_zerofill(fd, current_length, offset - current_length)) {
             error_setg_errno(errp, errno, "Could not zerofill the new area");
             return -errno;
         }
         break;
 #endif /* CONFIG_GLUSTERFS_ZEROFILL */
     case PREALLOC_MODE_OFF:
         if (glfs_ftruncate(fd, offset)) {
             error_setg_errno(errp, errno, "Could not resize file");
             return -errno;
         }
         break;
     default:
         error_setg(errp, "Unsupported preallocation mode: %s",
                    PreallocMode_str(prealloc));
         return -EINVAL;
     }
 
     return 0;
 }
 
 static int qemu_gluster_co_create(BlockdevCreateOptions *options,
                                   Error **errp)
 {
     BlockdevCreateOptionsGluster *opts = &options->u.gluster;
     struct glfs *glfs;
     struct glfs_fd *fd = NULL;
     int ret = 0;
 
     assert(options->driver == BLOCKDEV_DRIVER_GLUSTER);
 
     glfs = qemu_gluster_glfs_init(opts->location, errp);
     if (!glfs) {
         ret = -errno;
         goto out;
     }
 
     fd = glfs_creat(glfs, opts->location->path,
                     O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, S_IRUSR | S_IWUSR);
     if (!fd) {
         ret = -errno;
         goto out;
     }
 
     ret = qemu_gluster_do_truncate(fd, opts->size, opts->preallocation, errp);
 
 out:
     if (fd) {
         if (glfs_close(fd) != 0 && ret == 0) {
             ret = -errno;
         }
     }
     glfs_clear_preopened(glfs);
     return ret;
 }
 
 static int coroutine_fn qemu_gluster_co_create_opts(BlockDriver *drv,
                                                     const char *filename,
                                                     QemuOpts *opts,
                                                     Error **errp)
 {
     BlockdevCreateOptions *options;
     BlockdevCreateOptionsGluster *gopts;
     BlockdevOptionsGluster *gconf;
     char *tmp = NULL;
     Error *local_err = NULL;
     int ret;
 
     options = g_new0(BlockdevCreateOptions, 1);
     options->driver = BLOCKDEV_DRIVER_GLUSTER;
     gopts = &options->u.gluster;
 
     gconf = g_new0(BlockdevOptionsGluster, 1);
     gopts->location = gconf;
 
     gopts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
                            BDRV_SECTOR_SIZE);
 
     tmp = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
     gopts->preallocation = qapi_enum_parse(&PreallocMode_lookup, tmp,
                                            PREALLOC_MODE_OFF, &local_err);
     g_free(tmp);
     if (local_err) {
         error_propagate(errp, local_err);
         ret = -EINVAL;
         goto fail;
     }
 
     gconf->debug = qemu_opt_get_number_del(opts, GLUSTER_OPT_DEBUG,
                                            GLUSTER_DEBUG_DEFAULT);
     if (gconf->debug < 0) {
         gconf->debug = 0;
     } else if (gconf->debug > GLUSTER_DEBUG_MAX) {
         gconf->debug = GLUSTER_DEBUG_MAX;
     }
     gconf->has_debug = true;
 
     gconf->logfile = qemu_opt_get_del(opts, GLUSTER_OPT_LOGFILE);
     if (!gconf->logfile) {
         gconf->logfile = g_strdup(GLUSTER_LOGFILE_DEFAULT);
     }
     gconf->has_logfile = true;
 
     ret = qemu_gluster_parse(gconf, filename, NULL, errp);
     if (ret < 0) {
         goto fail;
     }
 
     ret = qemu_gluster_co_create(options, errp);
     if (ret < 0) {
         goto fail;
     }
 
     ret = 0;
 fail:
     qapi_free_BlockdevCreateOptions(options);
     return ret;
 }
 
 static coroutine_fn int qemu_gluster_co_rw(BlockDriverState *bs,
                                            int64_t sector_num, int nb_sectors,
                                            QEMUIOVector *qiov, int write)
 {
     int ret;
     GlusterAIOCB acb;
     BDRVGlusterState *s = bs->opaque;
     size_t size = nb_sectors * BDRV_SECTOR_SIZE;
     off_t offset = sector_num * BDRV_SECTOR_SIZE;
 
     acb.size = size;
     acb.ret = 0;
     acb.coroutine = qemu_coroutine_self();
     acb.aio_context = bdrv_get_aio_context(bs);
 
     if (write) {
         ret = glfs_pwritev_async(s->fd, qiov->iov, qiov->niov, offset, 0,
                                  gluster_finish_aiocb, &acb);
     } else {
         ret = glfs_preadv_async(s->fd, qiov->iov, qiov->niov, offset, 0,
                                 gluster_finish_aiocb, &acb);
     }
 
     if (ret < 0) {
         return -errno;
     }
 
     qemu_coroutine_yield();
     return acb.ret;
 }
 
 static coroutine_fn int qemu_gluster_co_truncate(BlockDriverState *bs,
                                                  int64_t offset,
                                                  bool exact,
                                                  PreallocMode prealloc,
                                                  BdrvRequestFlags flags,
                                                  Error **errp)
 {
     BDRVGlusterState *s = bs->opaque;
     return qemu_gluster_do_truncate(s->fd, offset, prealloc, errp);
 }
 
 static coroutine_fn int qemu_gluster_co_readv(BlockDriverState *bs,
                                               int64_t sector_num,
                                               int nb_sectors,
                                               QEMUIOVector *qiov)
 {
     return qemu_gluster_co_rw(bs, sector_num, nb_sectors, qiov, 0);
 }
 
 static coroutine_fn int qemu_gluster_co_writev(BlockDriverState *bs,
                                                int64_t sector_num,
                                                int nb_sectors,
                                                QEMUIOVector *qiov,
                                                int flags)
 {
     return qemu_gluster_co_rw(bs, sector_num, nb_sectors, qiov, 1);
 }
 
 static void qemu_gluster_close(BlockDriverState *bs)
 {
     BDRVGlusterState *s = bs->opaque;
 
     g_free(s->logfile);
     if (s->fd) {
         glfs_close(s->fd);
         s->fd = NULL;
     }
     glfs_clear_preopened(s->glfs);
 }
 
 static coroutine_fn int qemu_gluster_co_flush_to_disk(BlockDriverState *bs)
 {
     int ret;
     GlusterAIOCB acb;
     BDRVGlusterState *s = bs->opaque;
 
     acb.size = 0;
     acb.ret = 0;
     acb.coroutine = qemu_coroutine_self();
     acb.aio_context = bdrv_get_aio_context(bs);
 
     ret = glfs_fsync_async(s->fd, gluster_finish_aiocb, &acb);
     if (ret < 0) {
         ret = -errno;
         goto error;
     }
 
     qemu_coroutine_yield();
     if (acb.ret < 0) {
         ret = acb.ret;
         goto error;
     }
 
     return acb.ret;
 
 error:
     /* Some versions of Gluster (3.5.6 -> 3.5.8?) will not retain its cache
      * after a fsync failure, so we have no way of allowing the guest to safely
      * continue.  Gluster versions prior to 3.5.6 don't retain the cache
      * either, but will invalidate the fd on error, so this is again our only
      * option.
      *
      * The 'resync-failed-syncs-after-fsync' xlator option for the
      * write-behind cache will cause later gluster versions to retain its
      * cache after error, so long as the fd remains open.  However, we
      * currently have no way of knowing if this option is supported.
      *
      * TODO: Once gluster provides a way for us to determine if the option
      * is supported, bypass the closure and setting drv to NULL.  */
     qemu_gluster_close(bs);
     bs->drv = NULL;
     return ret;
 }
 
 #ifdef CONFIG_GLUSTERFS_DISCARD
 static coroutine_fn int qemu_gluster_co_pdiscard(BlockDriverState *bs,
                                                  int64_t offset, int64_t bytes)
 {
     int ret;
     GlusterAIOCB acb;
     BDRVGlusterState *s = bs->opaque;
 
     assert(bytes <= SIZE_MAX); /* rely on max_pdiscard */
 
     acb.size = 0;
     acb.ret = 0;
     acb.coroutine = qemu_coroutine_self();
     acb.aio_context = bdrv_get_aio_context(bs);
 
     ret = glfs_discard_async(s->fd, offset, bytes, gluster_finish_aiocb, &acb);
     if (ret < 0) {
         return -errno;
     }
 
     qemu_coroutine_yield();
     return acb.ret;
 }
 #endif
 
 static int64_t qemu_gluster_getlength(BlockDriverState *bs)
 {
     BDRVGlusterState *s = bs->opaque;
     int64_t ret;
 
     ret = glfs_lseek(s->fd, 0, SEEK_END);
     if (ret < 0) {
         return -errno;
     } else {
         return ret;
     }
 }
 
 static int64_t qemu_gluster_allocated_file_size(BlockDriverState *bs)
 {
     BDRVGlusterState *s = bs->opaque;
     struct stat st;
     int ret;
 
     ret = glfs_fstat(s->fd, &st);
     if (ret < 0) {
         return -errno;
     } else {
         return st.st_blocks * 512;
     }
 }
 
 /*
  * Find allocation range in @bs around offset @start.
  * May change underlying file descriptor's file offset.
  * If @start is not in a hole, store @start in @data, and the
  * beginning of the next hole in @hole, and return 0.
  * If @start is in a non-trailing hole, store @start in @hole and the
  * beginning of the next non-hole in @data, and return 0.
  * If @start is in a trailing hole or beyond EOF, return -ENXIO.
  * If we can't find out, return a negative errno other than -ENXIO.
  *
  * (Shamefully copied from file-posix.c, only minuscule adaptions.)
  */
 static int find_allocation(BlockDriverState *bs, off_t start,
                            off_t *data, off_t *hole)
 {
     BDRVGlusterState *s = bs->opaque;
 
     if (!s->supports_seek_data) {
         goto exit;
     }
 
 #if defined SEEK_HOLE && defined SEEK_DATA
     off_t offs;
 
     /*
      * SEEK_DATA cases:
      * D1. offs == start: start is in data
      * D2. offs > start: start is in a hole, next data at offs
      * D3. offs < 0, errno = ENXIO: either start is in a trailing hole
      *                              or start is beyond EOF
      *     If the latter happens, the file has been truncated behind
      *     our back since we opened it.  All bets are off then.
      *     Treating like a trailing hole is simplest.
      * D4. offs < 0, errno != ENXIO: we learned nothing
      */
     offs = glfs_lseek(s->fd, start, SEEK_DATA);
     if (offs < 0) {
         return -errno;          /* D3 or D4 */
     }
 
     if (offs < start) {
         /* This is not a valid return by lseek().  We are safe to just return
          * -EIO in this case, and we'll treat it like D4. Unfortunately some
          *  versions of gluster server will return offs < start, so an assert
          *  here will unnecessarily abort QEMU. */
         return -EIO;
     }
 
     if (offs > start) {
         /* D2: in hole, next data at offs */
         *hole = start;
         *data = offs;
         return 0;
     }
 
     /* D1: in data, end not yet known */
 
     /*
      * SEEK_HOLE cases:
      * H1. offs == start: start is in a hole
      *     If this happens here, a hole has been dug behind our back
      *     since the previous lseek().
      * H2. offs > start: either start is in data, next hole at offs,
      *                   or start is in trailing hole, EOF at offs
      *     Linux treats trailing holes like any other hole: offs ==
      *     start.  Solaris seeks to EOF instead: offs > start (blech).
      *     If that happens here, a hole has been dug behind our back
      *     since the previous lseek().
      * H3. offs < 0, errno = ENXIO: start is beyond EOF
      *     If this happens, the file has been truncated behind our
      *     back since we opened it.  Treat it like a trailing hole.
      * H4. offs < 0, errno != ENXIO: we learned nothing
      *     Pretend we know nothing at all, i.e. "forget" about D1.
      */
     offs = glfs_lseek(s->fd, start, SEEK_HOLE);
     if (offs < 0) {
         return -errno;          /* D1 and (H3 or H4) */
     }
 
     if (offs < start) {
         /* This is not a valid return by lseek().  We are safe to just return
          * -EIO in this case, and we'll treat it like H4. Unfortunately some
          *  versions of gluster server will return offs < start, so an assert
          *  here will unnecessarily abort QEMU. */
         return -EIO;
     }
 
     if (offs > start) {
         /*
          * D1 and H2: either in data, next hole at offs, or it was in
          * data but is now in a trailing hole.  In the latter case,
          * all bets are off.  Treating it as if it there was data all
          * the way to EOF is safe, so simply do that.
          */
         *data = start;
         *hole = offs;
         return 0;
     }
 
     /* D1 and H1 */
     return -EBUSY;
 #endif
 
 exit:
     return -ENOTSUP;
 }
 
 /*
  * Returns the allocation status of the specified offset.
  *
  * The block layer guarantees 'offset' and 'bytes' are within bounds.
  *
  * 'pnum' is set to the number of bytes (including and immediately following
  * the specified offset) that are known to be in the same
  * allocated/unallocated state.
  *
  * 'bytes' is a soft cap for 'pnum'.  If the information is free, 'pnum' may
  * well exceed it.
  *
  * (Based on raw_co_block_status() from file-posix.c.)
  */
 static int coroutine_fn qemu_gluster_co_block_status(BlockDriverState *bs,
                                                      bool want_zero,
                                                      int64_t offset,
                                                      int64_t bytes,
                                                      int64_t *pnum,
                                                      int64_t *map,
                                                      BlockDriverState **file)
 {
     BDRVGlusterState *s = bs->opaque;
     off_t data = 0, hole = 0;
     int ret = -EINVAL;
 
     assert(QEMU_IS_ALIGNED(offset | bytes, bs->bl.request_alignment));
 
     if (!s->fd) {
         return ret;
     }
 
     if (!want_zero) {
         *pnum = bytes;
         *map = offset;
         *file = bs;
         return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
     }
 
     ret = find_allocation(bs, offset, &data, &hole);
     if (ret == -ENXIO) {
         /* Trailing hole */
         *pnum = bytes;
         ret = BDRV_BLOCK_ZERO;
     } else if (ret < 0) {
         /* No info available, so pretend there are no holes */
         *pnum = bytes;
         ret = BDRV_BLOCK_DATA;
     } else if (data == offset) {
         /* On a data extent, compute bytes to the end of the extent,
          * possibly including a partial sector at EOF. */
         *pnum = hole - offset;
 
         /*
          * We are not allowed to return partial sectors, though, so
          * round up if necessary.
          */
         if (!QEMU_IS_ALIGNED(*pnum, bs->bl.request_alignment)) {
             int64_t file_length = qemu_gluster_getlength(bs);
             if (file_length > 0) {
                 /* Ignore errors, this is just a safeguard */
                 assert(hole == file_length);
             }
             *pnum = ROUND_UP(*pnum, bs->bl.request_alignment);
         }
 
         ret = BDRV_BLOCK_DATA;
     } else {
         /* On a hole, compute bytes to the beginning of the next extent.  */
         assert(hole == offset);
         *pnum = data - offset;
         ret = BDRV_BLOCK_ZERO;
     }
 
     *map = offset;
     *file = bs;
 
     return ret | BDRV_BLOCK_OFFSET_VALID;
 }
 
 
 static const char *const gluster_strong_open_opts[] = {
     GLUSTER_OPT_VOLUME,
     GLUSTER_OPT_PATH,
     GLUSTER_OPT_TYPE,
     GLUSTER_OPT_SERVER_PATTERN,
     GLUSTER_OPT_HOST,
     GLUSTER_OPT_PORT,
     GLUSTER_OPT_TO,
     GLUSTER_OPT_IPV4,
     GLUSTER_OPT_IPV6,
     GLUSTER_OPT_SOCKET,
 
     NULL
 };
 
 static BlockDriver bdrv_gluster = {
     .format_name                  = "gluster",
     .protocol_name                = "gluster",
     .instance_size                = sizeof(BDRVGlusterState),
     .bdrv_file_open               = qemu_gluster_open,
     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
     .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
     .bdrv_close                   = qemu_gluster_close,
     .bdrv_co_create               = qemu_gluster_co_create,
     .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
     .bdrv_getlength               = qemu_gluster_getlength,
     .bdrv_get_allocated_file_size = qemu_gluster_allocated_file_size,
     .bdrv_co_truncate             = qemu_gluster_co_truncate,
     .bdrv_co_readv                = qemu_gluster_co_readv,
     .bdrv_co_writev               = qemu_gluster_co_writev,
     .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
 #ifdef CONFIG_GLUSTERFS_DISCARD
     .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
 #endif
 #ifdef CONFIG_GLUSTERFS_ZEROFILL
     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
     .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
     .create_opts                  = &qemu_gluster_create_opts,
     .strong_runtime_opts          = gluster_strong_open_opts,
 };
 
 static BlockDriver bdrv_gluster_tcp = {
     .format_name                  = "gluster",
     .protocol_name                = "gluster+tcp",
     .instance_size                = sizeof(BDRVGlusterState),
     .bdrv_file_open               = qemu_gluster_open,
     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
     .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
     .bdrv_close                   = qemu_gluster_close,
     .bdrv_co_create               = qemu_gluster_co_create,
     .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
     .bdrv_getlength               = qemu_gluster_getlength,
     .bdrv_get_allocated_file_size = qemu_gluster_allocated_file_size,
     .bdrv_co_truncate             = qemu_gluster_co_truncate,
     .bdrv_co_readv                = qemu_gluster_co_readv,
     .bdrv_co_writev               = qemu_gluster_co_writev,
     .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
 #ifdef CONFIG_GLUSTERFS_DISCARD
     .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
 #endif
 #ifdef CONFIG_GLUSTERFS_ZEROFILL
     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
     .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
     .create_opts                  = &qemu_gluster_create_opts,
     .strong_runtime_opts          = gluster_strong_open_opts,
 };
 
 static BlockDriver bdrv_gluster_unix = {
     .format_name                  = "gluster",
     .protocol_name                = "gluster+unix",
     .instance_size                = sizeof(BDRVGlusterState),
     .bdrv_file_open               = qemu_gluster_open,
     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
     .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
     .bdrv_close                   = qemu_gluster_close,
     .bdrv_co_create               = qemu_gluster_co_create,
     .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
     .bdrv_getlength               = qemu_gluster_getlength,
     .bdrv_get_allocated_file_size = qemu_gluster_allocated_file_size,
     .bdrv_co_truncate             = qemu_gluster_co_truncate,
     .bdrv_co_readv                = qemu_gluster_co_readv,
     .bdrv_co_writev               = qemu_gluster_co_writev,
     .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
 #ifdef CONFIG_GLUSTERFS_DISCARD
     .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
 #endif
 #ifdef CONFIG_GLUSTERFS_ZEROFILL
     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
     .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
     .create_opts                  = &qemu_gluster_create_opts,
     .strong_runtime_opts          = gluster_strong_open_opts,
 };
 
 /* rdma is deprecated (actually never supported for volfile fetch).
  * Let's maintain it for the protocol compatibility, to make sure things
  * won't break immediately. For now, gluster+rdma will fall back to gluster+tcp
  * protocol with a warning.
  * TODO: remove gluster+rdma interface support
  */
 static BlockDriver bdrv_gluster_rdma = {
     .format_name                  = "gluster",
     .protocol_name                = "gluster+rdma",
     .instance_size                = sizeof(BDRVGlusterState),
     .bdrv_file_open               = qemu_gluster_open,
     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
     .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
     .bdrv_close                   = qemu_gluster_close,
     .bdrv_co_create               = qemu_gluster_co_create,
     .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
     .bdrv_getlength               = qemu_gluster_getlength,
     .bdrv_get_allocated_file_size = qemu_gluster_allocated_file_size,
     .bdrv_co_truncate             = qemu_gluster_co_truncate,
     .bdrv_co_readv                = qemu_gluster_co_readv,
     .bdrv_co_writev               = qemu_gluster_co_writev,
     .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
 #ifdef CONFIG_GLUSTERFS_DISCARD
     .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
 #endif
 #ifdef CONFIG_GLUSTERFS_ZEROFILL
     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
 #endif
     .bdrv_co_block_status         = qemu_gluster_co_block_status,
     .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
     .create_opts                  = &qemu_gluster_create_opts,
     .strong_runtime_opts          = gluster_strong_open_opts,
 };
 
 static void bdrv_gluster_init(void)
 {
     bdrv_register(&bdrv_gluster_rdma);
     bdrv_register(&bdrv_gluster_unix);
     bdrv_register(&bdrv_gluster_tcp);
     bdrv_register(&bdrv_gluster);
 }
 
 block_init(bdrv_gluster_init);