xref: /openbmc/qemu/block/gluster.c (revision 125062e791258c68109f3a59cb7aca3dadbdb5a3)
1  /*
2   * GlusterFS backend for QEMU
3   *
4   * Copyright (C) 2012 Bharata B Rao <bharata@linux.vnet.ibm.com>
5   *
6   * This work is licensed under the terms of the GNU GPL, version 2 or later.
7   * See the COPYING file in the top-level directory.
8   *
9   */
10  
11  #include "qemu/osdep.h"
12  #include "qemu/units.h"
13  #include <glusterfs/api/glfs.h>
14  #include "block/block-io.h"
15  #include "block/block_int.h"
16  #include "block/qdict.h"
17  #include "qapi/error.h"
18  #include "qapi/qmp/qdict.h"
19  #include "qapi/qmp/qerror.h"
20  #include "qemu/uri.h"
21  #include "qemu/error-report.h"
22  #include "qemu/module.h"
23  #include "qemu/option.h"
24  #include "qemu/cutils.h"
25  
26  #ifdef CONFIG_GLUSTERFS_FTRUNCATE_HAS_STAT
27  # define glfs_ftruncate(fd, offset) glfs_ftruncate(fd, offset, NULL, NULL)
28  #endif
29  
30  #define GLUSTER_OPT_FILENAME        "filename"
31  #define GLUSTER_OPT_VOLUME          "volume"
32  #define GLUSTER_OPT_PATH            "path"
33  #define GLUSTER_OPT_TYPE            "type"
34  #define GLUSTER_OPT_SERVER_PATTERN  "server."
35  #define GLUSTER_OPT_HOST            "host"
36  #define GLUSTER_OPT_PORT            "port"
37  #define GLUSTER_OPT_TO              "to"
38  #define GLUSTER_OPT_IPV4            "ipv4"
39  #define GLUSTER_OPT_IPV6            "ipv6"
40  #define GLUSTER_OPT_SOCKET          "socket"
41  #define GLUSTER_OPT_DEBUG           "debug"
42  #define GLUSTER_DEFAULT_PORT        24007
43  #define GLUSTER_DEBUG_DEFAULT       4
44  #define GLUSTER_DEBUG_MAX           9
45  #define GLUSTER_OPT_LOGFILE         "logfile"
46  #define GLUSTER_LOGFILE_DEFAULT     "-" /* handled in libgfapi as /dev/stderr */
47  /*
48   * Several versions of GlusterFS (3.12? -> 6.0.1) fail when the transfer size
49   * is greater or equal to 1024 MiB, so we are limiting the transfer size to 512
50   * MiB to avoid this rare issue.
51   */
52  #define GLUSTER_MAX_TRANSFER        (512 * MiB)
53  
54  #define GERR_INDEX_HINT "hint: check in 'server' array index '%d'\n"
55  
56  typedef struct GlusterAIOCB {
57      int64_t size;
58      int ret;
59      Coroutine *coroutine;
60      AioContext *aio_context;
61  } GlusterAIOCB;
62  
63  typedef struct BDRVGlusterState {
64      struct glfs *glfs;
65      struct glfs_fd *fd;
66      char *logfile;
67      bool supports_seek_data;
68      int debug;
69  } BDRVGlusterState;
70  
71  typedef struct BDRVGlusterReopenState {
72      struct glfs *glfs;
73      struct glfs_fd *fd;
74  } BDRVGlusterReopenState;
75  
76  
77  typedef struct GlfsPreopened {
78      char *volume;
79      glfs_t *fs;
80      int ref;
81  } GlfsPreopened;
82  
83  typedef struct ListElement {
84      QLIST_ENTRY(ListElement) list;
85      GlfsPreopened saved;
86  } ListElement;
87  
88  static QLIST_HEAD(, ListElement) glfs_list;
89  
90  static QemuOptsList qemu_gluster_create_opts = {
91      .name = "qemu-gluster-create-opts",
92      .head = QTAILQ_HEAD_INITIALIZER(qemu_gluster_create_opts.head),
93      .desc = {
94          {
95              .name = BLOCK_OPT_SIZE,
96              .type = QEMU_OPT_SIZE,
97              .help = "Virtual disk size"
98          },
99          {
100              .name = BLOCK_OPT_PREALLOC,
101              .type = QEMU_OPT_STRING,
102              .help = "Preallocation mode (allowed values: off"
103  #ifdef CONFIG_GLUSTERFS_FALLOCATE
104                      ", falloc"
105  #endif
106  #ifdef CONFIG_GLUSTERFS_ZEROFILL
107                      ", full"
108  #endif
109                      ")"
110          },
111          {
112              .name = GLUSTER_OPT_DEBUG,
113              .type = QEMU_OPT_NUMBER,
114              .help = "Gluster log level, valid range is 0-9",
115          },
116          {
117              .name = GLUSTER_OPT_LOGFILE,
118              .type = QEMU_OPT_STRING,
119              .help = "Logfile path of libgfapi",
120          },
121          { /* end of list */ }
122      }
123  };
124  
125  static QemuOptsList runtime_opts = {
126      .name = "gluster",
127      .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
128      .desc = {
129          {
130              .name = GLUSTER_OPT_FILENAME,
131              .type = QEMU_OPT_STRING,
132              .help = "URL to the gluster image",
133          },
134          {
135              .name = GLUSTER_OPT_DEBUG,
136              .type = QEMU_OPT_NUMBER,
137              .help = "Gluster log level, valid range is 0-9",
138          },
139          {
140              .name = GLUSTER_OPT_LOGFILE,
141              .type = QEMU_OPT_STRING,
142              .help = "Logfile path of libgfapi",
143          },
144          { /* end of list */ }
145      },
146  };
147  
148  static QemuOptsList runtime_json_opts = {
149      .name = "gluster_json",
150      .head = QTAILQ_HEAD_INITIALIZER(runtime_json_opts.head),
151      .desc = {
152          {
153              .name = GLUSTER_OPT_VOLUME,
154              .type = QEMU_OPT_STRING,
155              .help = "name of gluster volume where VM image resides",
156          },
157          {
158              .name = GLUSTER_OPT_PATH,
159              .type = QEMU_OPT_STRING,
160              .help = "absolute path to image file in gluster volume",
161          },
162          {
163              .name = GLUSTER_OPT_DEBUG,
164              .type = QEMU_OPT_NUMBER,
165              .help = "Gluster log level, valid range is 0-9",
166          },
167          { /* end of list */ }
168      },
169  };
170  
171  static QemuOptsList runtime_type_opts = {
172      .name = "gluster_type",
173      .head = QTAILQ_HEAD_INITIALIZER(runtime_type_opts.head),
174      .desc = {
175          {
176              .name = GLUSTER_OPT_TYPE,
177              .type = QEMU_OPT_STRING,
178              .help = "inet|unix",
179          },
180          { /* end of list */ }
181      },
182  };
183  
184  static QemuOptsList runtime_unix_opts = {
185      .name = "gluster_unix",
186      .head = QTAILQ_HEAD_INITIALIZER(runtime_unix_opts.head),
187      .desc = {
188          {
189              .name = GLUSTER_OPT_SOCKET,
190              .type = QEMU_OPT_STRING,
191              .help = "socket file path (legacy)",
192          },
193          {
194              .name = GLUSTER_OPT_PATH,
195              .type = QEMU_OPT_STRING,
196              .help = "socket file path (QAPI)",
197          },
198          { /* end of list */ }
199      },
200  };
201  
202  static QemuOptsList runtime_inet_opts = {
203      .name = "gluster_inet",
204      .head = QTAILQ_HEAD_INITIALIZER(runtime_inet_opts.head),
205      .desc = {
206          {
207              .name = GLUSTER_OPT_TYPE,
208              .type = QEMU_OPT_STRING,
209              .help = "inet|unix",
210          },
211          {
212              .name = GLUSTER_OPT_HOST,
213              .type = QEMU_OPT_STRING,
214              .help = "host address (hostname/ipv4/ipv6 addresses)",
215          },
216          {
217              .name = GLUSTER_OPT_PORT,
218              .type = QEMU_OPT_STRING,
219              .help = "port number on which glusterd is listening (default 24007)",
220          },
221          {
222              .name = "to",
223              .type = QEMU_OPT_NUMBER,
224              .help = "max port number, not supported by gluster",
225          },
226          {
227              .name = "ipv4",
228              .type = QEMU_OPT_BOOL,
229              .help = "ipv4 bool value, not supported by gluster",
230          },
231          {
232              .name = "ipv6",
233              .type = QEMU_OPT_BOOL,
234              .help = "ipv6 bool value, not supported by gluster",
235          },
236          { /* end of list */ }
237      },
238  };
239  
240  static void glfs_set_preopened(const char *volume, glfs_t *fs)
241  {
242      ListElement *entry = NULL;
243  
244      entry = g_new(ListElement, 1);
245  
246      entry->saved.volume = g_strdup(volume);
247  
248      entry->saved.fs = fs;
249      entry->saved.ref = 1;
250  
251      QLIST_INSERT_HEAD(&glfs_list, entry, list);
252  }
253  
254  static glfs_t *glfs_find_preopened(const char *volume)
255  {
256      ListElement *entry = NULL;
257  
258       QLIST_FOREACH(entry, &glfs_list, list) {
259          if (strcmp(entry->saved.volume, volume) == 0) {
260              entry->saved.ref++;
261              return entry->saved.fs;
262          }
263       }
264  
265      return NULL;
266  }
267  
268  static void glfs_clear_preopened(glfs_t *fs)
269  {
270      ListElement *entry = NULL;
271      ListElement *next;
272  
273      if (fs == NULL) {
274          return;
275      }
276  
277      QLIST_FOREACH_SAFE(entry, &glfs_list, list, next) {
278          if (entry->saved.fs == fs) {
279              if (--entry->saved.ref) {
280                  return;
281              }
282  
283              QLIST_REMOVE(entry, list);
284  
285              glfs_fini(entry->saved.fs);
286              g_free(entry->saved.volume);
287              g_free(entry);
288          }
289      }
290  }
291  
292  static int parse_volume_options(BlockdevOptionsGluster *gconf, char *path)
293  {
294      char *p, *q;
295  
296      if (!path) {
297          return -EINVAL;
298      }
299  
300      /* volume */
301      p = q = path + strspn(path, "/");
302      p += strcspn(p, "/");
303      if (*p == '\0') {
304          return -EINVAL;
305      }
306      gconf->volume = g_strndup(q, p - q);
307  
308      /* path */
309      p += strspn(p, "/");
310      if (*p == '\0') {
311          return -EINVAL;
312      }
313      gconf->path = g_strdup(p);
314      return 0;
315  }
316  
317  /*
318   * file=gluster[+transport]://[host[:port]]/volume/path[?socket=...]
319   *
320   * 'gluster' is the protocol.
321   *
322   * 'transport' specifies the transport type used to connect to gluster
323   * management daemon (glusterd). Valid transport types are
324   * tcp or unix. If a transport type isn't specified, then tcp type is assumed.
325   *
326   * 'host' specifies the host where the volume file specification for
327   * the given volume resides. This can be either hostname or ipv4 address.
328   * If transport type is 'unix', then 'host' field should not be specified.
329   * The 'socket' field needs to be populated with the path to unix domain
330   * socket.
331   *
332   * 'port' is the port number on which glusterd is listening. This is optional
333   * and if not specified, QEMU will send 0 which will make gluster to use the
334   * default port. If the transport type is unix, then 'port' should not be
335   * specified.
336   *
337   * 'volume' is the name of the gluster volume which contains the VM image.
338   *
339   * 'path' is the path to the actual VM image that resides on gluster volume.
340   *
341   * Examples:
342   *
343   * file=gluster://1.2.3.4/testvol/a.img
344   * file=gluster+tcp://1.2.3.4/testvol/a.img
345   * file=gluster+tcp://1.2.3.4:24007/testvol/dir/a.img
346   * file=gluster+tcp://host.domain.com:24007/testvol/dir/a.img
347   * file=gluster+unix:///testvol/dir/a.img?socket=/tmp/glusterd.socket
348   */
349  static int qemu_gluster_parse_uri(BlockdevOptionsGluster *gconf,
350                                    const char *filename)
351  {
352      SocketAddress *gsconf;
353      URI *uri;
354      QueryParams *qp = NULL;
355      bool is_unix = false;
356      int ret = 0;
357  
358      uri = uri_parse(filename);
359      if (!uri) {
360          return -EINVAL;
361      }
362  
363      gsconf = g_new0(SocketAddress, 1);
364      QAPI_LIST_PREPEND(gconf->server, gsconf);
365  
366      /* transport */
367      if (!uri->scheme || !strcmp(uri->scheme, "gluster")) {
368          gsconf->type = SOCKET_ADDRESS_TYPE_INET;
369      } else if (!strcmp(uri->scheme, "gluster+tcp")) {
370          gsconf->type = SOCKET_ADDRESS_TYPE_INET;
371      } else if (!strcmp(uri->scheme, "gluster+unix")) {
372          gsconf->type = SOCKET_ADDRESS_TYPE_UNIX;
373          is_unix = true;
374      } else if (!strcmp(uri->scheme, "gluster+rdma")) {
375          gsconf->type = SOCKET_ADDRESS_TYPE_INET;
376          warn_report("rdma feature is not supported, falling back to tcp");
377      } else {
378          ret = -EINVAL;
379          goto out;
380      }
381  
382      ret = parse_volume_options(gconf, uri->path);
383      if (ret < 0) {
384          goto out;
385      }
386  
387      qp = query_params_parse(uri->query);
388      if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
389          ret = -EINVAL;
390          goto out;
391      }
392  
393      if (is_unix) {
394          if (uri->server || uri->port) {
395              ret = -EINVAL;
396              goto out;
397          }
398          if (strcmp(qp->p[0].name, "socket")) {
399              ret = -EINVAL;
400              goto out;
401          }
402          gsconf->u.q_unix.path = g_strdup(qp->p[0].value);
403      } else {
404          gsconf->u.inet.host = g_strdup(uri->server ? uri->server : "localhost");
405          if (uri->port) {
406              gsconf->u.inet.port = g_strdup_printf("%d", uri->port);
407          } else {
408              gsconf->u.inet.port = g_strdup_printf("%d", GLUSTER_DEFAULT_PORT);
409          }
410      }
411  
412  out:
413      if (qp) {
414          query_params_free(qp);
415      }
416      uri_free(uri);
417      return ret;
418  }
419  
420  static struct glfs *qemu_gluster_glfs_init(BlockdevOptionsGluster *gconf,
421                                             Error **errp)
422  {
423      struct glfs *glfs;
424      int ret;
425      int old_errno;
426      SocketAddressList *server;
427      uint64_t port;
428  
429      glfs = glfs_find_preopened(gconf->volume);
430      if (glfs) {
431          return glfs;
432      }
433  
434      glfs = glfs_new(gconf->volume);
435      if (!glfs) {
436          goto out;
437      }
438  
439      glfs_set_preopened(gconf->volume, glfs);
440  
441      for (server = gconf->server; server; server = server->next) {
442          switch (server->value->type) {
443          case SOCKET_ADDRESS_TYPE_UNIX:
444              ret = glfs_set_volfile_server(glfs, "unix",
445                                     server->value->u.q_unix.path, 0);
446              break;
447          case SOCKET_ADDRESS_TYPE_INET:
448              if (parse_uint_full(server->value->u.inet.port, 10, &port) < 0 ||
449                  port > 65535) {
450                  error_setg(errp, "'%s' is not a valid port number",
451                             server->value->u.inet.port);
452                  errno = EINVAL;
453                  goto out;
454              }
455              ret = glfs_set_volfile_server(glfs, "tcp",
456                                     server->value->u.inet.host,
457                                     (int)port);
458              break;
459          case SOCKET_ADDRESS_TYPE_VSOCK:
460          case SOCKET_ADDRESS_TYPE_FD:
461          default:
462              abort();
463          }
464  
465          if (ret < 0) {
466              goto out;
467          }
468      }
469  
470      ret = glfs_set_logging(glfs, gconf->logfile, gconf->debug);
471      if (ret < 0) {
472          goto out;
473      }
474  
475      ret = glfs_init(glfs);
476      if (ret) {
477          error_setg(errp, "Gluster connection for volume %s, path %s failed"
478                           " to connect", gconf->volume, gconf->path);
479          for (server = gconf->server; server; server = server->next) {
480              if (server->value->type  == SOCKET_ADDRESS_TYPE_UNIX) {
481                  error_append_hint(errp, "hint: failed on socket %s ",
482                                    server->value->u.q_unix.path);
483              } else {
484                  error_append_hint(errp, "hint: failed on host %s and port %s ",
485                                    server->value->u.inet.host,
486                                    server->value->u.inet.port);
487              }
488          }
489  
490          error_append_hint(errp, "Please refer to gluster logs for more info\n");
491  
492          /* glfs_init sometimes doesn't set errno although docs suggest that */
493          if (errno == 0) {
494              errno = EINVAL;
495          }
496  
497          goto out;
498      }
499      return glfs;
500  
501  out:
502      if (glfs) {
503          old_errno = errno;
504          glfs_clear_preopened(glfs);
505          errno = old_errno;
506      }
507      return NULL;
508  }
509  
510  /*
511   * Convert the json formatted command line into qapi.
512  */
513  static int qemu_gluster_parse_json(BlockdevOptionsGluster *gconf,
514                                    QDict *options, Error **errp)
515  {
516      QemuOpts *opts;
517      SocketAddress *gsconf = NULL;
518      SocketAddressList **tail;
519      QDict *backing_options = NULL;
520      Error *local_err = NULL;
521      char *str = NULL;
522      const char *ptr;
523      int i, type, num_servers;
524  
525      /* create opts info from runtime_json_opts list */
526      opts = qemu_opts_create(&runtime_json_opts, NULL, 0, &error_abort);
527      if (!qemu_opts_absorb_qdict(opts, options, errp)) {
528          goto out;
529      }
530  
531      num_servers = qdict_array_entries(options, GLUSTER_OPT_SERVER_PATTERN);
532      if (num_servers < 1) {
533          error_setg(&local_err, QERR_MISSING_PARAMETER, "server");
534          goto out;
535      }
536  
537      ptr = qemu_opt_get(opts, GLUSTER_OPT_VOLUME);
538      if (!ptr) {
539          error_setg(&local_err, QERR_MISSING_PARAMETER, GLUSTER_OPT_VOLUME);
540          goto out;
541      }
542      gconf->volume = g_strdup(ptr);
543  
544      ptr = qemu_opt_get(opts, GLUSTER_OPT_PATH);
545      if (!ptr) {
546          error_setg(&local_err, QERR_MISSING_PARAMETER, GLUSTER_OPT_PATH);
547          goto out;
548      }
549      gconf->path = g_strdup(ptr);
550      qemu_opts_del(opts);
551      tail = &gconf->server;
552  
553      for (i = 0; i < num_servers; i++) {
554          str = g_strdup_printf(GLUSTER_OPT_SERVER_PATTERN"%d.", i);
555          qdict_extract_subqdict(options, &backing_options, str);
556  
557          /* create opts info from runtime_type_opts list */
558          opts = qemu_opts_create(&runtime_type_opts, NULL, 0, &error_abort);
559          if (!qemu_opts_absorb_qdict(opts, backing_options, errp)) {
560              goto out;
561          }
562  
563          ptr = qemu_opt_get(opts, GLUSTER_OPT_TYPE);
564          if (!ptr) {
565              error_setg(&local_err, QERR_MISSING_PARAMETER, GLUSTER_OPT_TYPE);
566              error_append_hint(&local_err, GERR_INDEX_HINT, i);
567              goto out;
568  
569          }
570          gsconf = g_new0(SocketAddress, 1);
571          if (!strcmp(ptr, "tcp")) {
572              ptr = "inet";       /* accept legacy "tcp" */
573          }
574          type = qapi_enum_parse(&SocketAddressType_lookup, ptr, -1, NULL);
575          if (type != SOCKET_ADDRESS_TYPE_INET
576              && type != SOCKET_ADDRESS_TYPE_UNIX) {
577              error_setg(&local_err,
578                         "Parameter '%s' may be 'inet' or 'unix'",
579                         GLUSTER_OPT_TYPE);
580              error_append_hint(&local_err, GERR_INDEX_HINT, i);
581              goto out;
582          }
583          gsconf->type = type;
584          qemu_opts_del(opts);
585  
586          if (gsconf->type == SOCKET_ADDRESS_TYPE_INET) {
587              /* create opts info from runtime_inet_opts list */
588              opts = qemu_opts_create(&runtime_inet_opts, NULL, 0, &error_abort);
589              if (!qemu_opts_absorb_qdict(opts, backing_options, errp)) {
590                  goto out;
591              }
592  
593              ptr = qemu_opt_get(opts, GLUSTER_OPT_HOST);
594              if (!ptr) {
595                  error_setg(&local_err, QERR_MISSING_PARAMETER,
596                             GLUSTER_OPT_HOST);
597                  error_append_hint(&local_err, GERR_INDEX_HINT, i);
598                  goto out;
599              }
600              gsconf->u.inet.host = g_strdup(ptr);
601              ptr = qemu_opt_get(opts, GLUSTER_OPT_PORT);
602              if (!ptr) {
603                  error_setg(&local_err, QERR_MISSING_PARAMETER,
604                             GLUSTER_OPT_PORT);
605                  error_append_hint(&local_err, GERR_INDEX_HINT, i);
606                  goto out;
607              }
608              gsconf->u.inet.port = g_strdup(ptr);
609  
610              /* defend for unsupported fields in InetSocketAddress,
611               * i.e. @ipv4, @ipv6  and @to
612               */
613              ptr = qemu_opt_get(opts, GLUSTER_OPT_TO);
614              if (ptr) {
615                  gsconf->u.inet.has_to = true;
616              }
617              ptr = qemu_opt_get(opts, GLUSTER_OPT_IPV4);
618              if (ptr) {
619                  gsconf->u.inet.has_ipv4 = true;
620              }
621              ptr = qemu_opt_get(opts, GLUSTER_OPT_IPV6);
622              if (ptr) {
623                  gsconf->u.inet.has_ipv6 = true;
624              }
625              if (gsconf->u.inet.has_to) {
626                  error_setg(&local_err, "Parameter 'to' not supported");
627                  goto out;
628              }
629              if (gsconf->u.inet.has_ipv4 || gsconf->u.inet.has_ipv6) {
630                  error_setg(&local_err, "Parameters 'ipv4/ipv6' not supported");
631                  goto out;
632              }
633              qemu_opts_del(opts);
634          } else {
635              /* create opts info from runtime_unix_opts list */
636              opts = qemu_opts_create(&runtime_unix_opts, NULL, 0, &error_abort);
637              if (!qemu_opts_absorb_qdict(opts, backing_options, errp)) {
638                  goto out;
639              }
640  
641              ptr = qemu_opt_get(opts, GLUSTER_OPT_PATH);
642              if (!ptr) {
643                  ptr = qemu_opt_get(opts, GLUSTER_OPT_SOCKET);
644              } else if (qemu_opt_get(opts, GLUSTER_OPT_SOCKET)) {
645                  error_setg(&local_err,
646                             "Conflicting parameters 'path' and 'socket'");
647                  error_append_hint(&local_err, GERR_INDEX_HINT, i);
648                  goto out;
649              }
650              if (!ptr) {
651                  error_setg(&local_err, QERR_MISSING_PARAMETER,
652                             GLUSTER_OPT_PATH);
653                  error_append_hint(&local_err, GERR_INDEX_HINT, i);
654                  goto out;
655              }
656              gsconf->u.q_unix.path = g_strdup(ptr);
657              qemu_opts_del(opts);
658          }
659  
660          QAPI_LIST_APPEND(tail, gsconf);
661          gsconf = NULL;
662  
663          qobject_unref(backing_options);
664          backing_options = NULL;
665          g_free(str);
666          str = NULL;
667      }
668  
669      return 0;
670  
671  out:
672      error_propagate(errp, local_err);
673      qapi_free_SocketAddress(gsconf);
674      qemu_opts_del(opts);
675      g_free(str);
676      qobject_unref(backing_options);
677      errno = EINVAL;
678      return -errno;
679  }
680  
681  /* Converts options given in @filename and the @options QDict into the QAPI
682   * object @gconf. */
683  static int qemu_gluster_parse(BlockdevOptionsGluster *gconf,
684                                const char *filename,
685                                QDict *options, Error **errp)
686  {
687      int ret;
688      if (filename) {
689          ret = qemu_gluster_parse_uri(gconf, filename);
690          if (ret < 0) {
691              error_setg(errp, "invalid URI %s", filename);
692              error_append_hint(errp, "Usage: file=gluster[+transport]://"
693                                      "[host[:port]]volume/path[?socket=...]"
694                                      "[,file.debug=N]"
695                                      "[,file.logfile=/path/filename.log]\n");
696              return ret;
697          }
698      } else {
699          ret = qemu_gluster_parse_json(gconf, options, errp);
700          if (ret < 0) {
701              error_append_hint(errp, "Usage: "
702                               "-drive driver=qcow2,file.driver=gluster,"
703                               "file.volume=testvol,file.path=/path/a.qcow2"
704                               "[,file.debug=9]"
705                               "[,file.logfile=/path/filename.log],"
706                               "file.server.0.type=inet,"
707                               "file.server.0.host=1.2.3.4,"
708                               "file.server.0.port=24007,"
709                               "file.server.1.transport=unix,"
710                               "file.server.1.path=/var/run/glusterd.socket ..."
711                               "\n");
712              return ret;
713          }
714      }
715  
716      return 0;
717  }
718  
719  static struct glfs *qemu_gluster_init(BlockdevOptionsGluster *gconf,
720                                        const char *filename,
721                                        QDict *options, Error **errp)
722  {
723      int ret;
724  
725      ret = qemu_gluster_parse(gconf, filename, options, errp);
726      if (ret < 0) {
727          errno = -ret;
728          return NULL;
729      }
730  
731      return qemu_gluster_glfs_init(gconf, errp);
732  }
733  
734  /*
735   * AIO callback routine called from GlusterFS thread.
736   */
737  static void gluster_finish_aiocb(struct glfs_fd *fd, ssize_t ret,
738  #ifdef CONFIG_GLUSTERFS_IOCB_HAS_STAT
739                                   struct glfs_stat *pre, struct glfs_stat *post,
740  #endif
741                                   void *arg)
742  {
743      GlusterAIOCB *acb = (GlusterAIOCB *)arg;
744  
745      if (!ret || ret == acb->size) {
746          acb->ret = 0; /* Success */
747      } else if (ret < 0) {
748          acb->ret = -errno; /* Read/Write failed */
749      } else {
750          acb->ret = -EIO; /* Partial read/write - fail it */
751      }
752  
753      aio_co_schedule(acb->aio_context, acb->coroutine);
754  }
755  
756  static void qemu_gluster_parse_flags(int bdrv_flags, int *open_flags)
757  {
758      assert(open_flags != NULL);
759  
760      *open_flags |= O_BINARY;
761  
762      if (bdrv_flags & BDRV_O_RDWR) {
763          *open_flags |= O_RDWR;
764      } else {
765          *open_flags |= O_RDONLY;
766      }
767  
768      if ((bdrv_flags & BDRV_O_NOCACHE)) {
769          *open_flags |= O_DIRECT;
770      }
771  }
772  
773  /*
774   * Do SEEK_DATA/HOLE to detect if it is functional. Older broken versions of
775   * gfapi incorrectly return the current offset when SEEK_DATA/HOLE is used.
776   * - Corrected versions return -1 and set errno to EINVAL.
777   * - Versions that support SEEK_DATA/HOLE correctly, will return -1 and set
778   *   errno to ENXIO when SEEK_DATA is called with a position of EOF.
779   */
780  static bool qemu_gluster_test_seek(struct glfs_fd *fd)
781  {
782      off_t ret = 0;
783  
784  #if defined SEEK_HOLE && defined SEEK_DATA
785      off_t eof;
786  
787      eof = glfs_lseek(fd, 0, SEEK_END);
788      if (eof < 0) {
789          /* this should never occur */
790          return false;
791      }
792  
793      /* this should always fail with ENXIO if SEEK_DATA is supported */
794      ret = glfs_lseek(fd, eof, SEEK_DATA);
795  #endif
796  
797      return (ret < 0) && (errno == ENXIO);
798  }
799  
800  static int qemu_gluster_open(BlockDriverState *bs,  QDict *options,
801                               int bdrv_flags, Error **errp)
802  {
803      BDRVGlusterState *s = bs->opaque;
804      int open_flags = 0;
805      int ret = 0;
806      BlockdevOptionsGluster *gconf = NULL;
807      QemuOpts *opts;
808      const char *filename, *logfile;
809  
810      opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
811      if (!qemu_opts_absorb_qdict(opts, options, errp)) {
812          ret = -EINVAL;
813          goto out;
814      }
815  
816      filename = qemu_opt_get(opts, GLUSTER_OPT_FILENAME);
817  
818      s->debug = qemu_opt_get_number(opts, GLUSTER_OPT_DEBUG,
819                                     GLUSTER_DEBUG_DEFAULT);
820      if (s->debug < 0) {
821          s->debug = 0;
822      } else if (s->debug > GLUSTER_DEBUG_MAX) {
823          s->debug = GLUSTER_DEBUG_MAX;
824      }
825  
826      gconf = g_new0(BlockdevOptionsGluster, 1);
827      gconf->debug = s->debug;
828      gconf->has_debug = true;
829  
830      logfile = qemu_opt_get(opts, GLUSTER_OPT_LOGFILE);
831      s->logfile = g_strdup(logfile ? logfile : GLUSTER_LOGFILE_DEFAULT);
832  
833      gconf->logfile = g_strdup(s->logfile);
834  
835      s->glfs = qemu_gluster_init(gconf, filename, options, errp);
836      if (!s->glfs) {
837          ret = -errno;
838          goto out;
839      }
840  
841  #ifdef CONFIG_GLUSTERFS_XLATOR_OPT
842      /* Without this, if fsync fails for a recoverable reason (for instance,
843       * ENOSPC), gluster will dump its cache, preventing retries.  This means
844       * almost certain data loss.  Not all gluster versions support the
845       * 'resync-failed-syncs-after-fsync' key value, but there is no way to
846       * discover during runtime if it is supported (this api returns success for
847       * unknown key/value pairs) */
848      ret = glfs_set_xlator_option(s->glfs, "*-write-behind",
849                                            "resync-failed-syncs-after-fsync",
850                                            "on");
851      if (ret < 0) {
852          error_setg_errno(errp, errno, "Unable to set xlator key/value pair");
853          ret = -errno;
854          goto out;
855      }
856  #endif
857  
858      qemu_gluster_parse_flags(bdrv_flags, &open_flags);
859  
860      s->fd = glfs_open(s->glfs, gconf->path, open_flags);
861      ret = s->fd ? 0 : -errno;
862  
863      if (ret == -EACCES || ret == -EROFS) {
864          /* Try to degrade to read-only, but if it doesn't work, still use the
865           * normal error message. */
866          bdrv_graph_rdlock_main_loop();
867          if (bdrv_apply_auto_read_only(bs, NULL, NULL) == 0) {
868              open_flags = (open_flags & ~O_RDWR) | O_RDONLY;
869              s->fd = glfs_open(s->glfs, gconf->path, open_flags);
870              ret = s->fd ? 0 : -errno;
871          }
872          bdrv_graph_rdunlock_main_loop();
873      }
874  
875      s->supports_seek_data = qemu_gluster_test_seek(s->fd);
876  
877  out:
878      qemu_opts_del(opts);
879      qapi_free_BlockdevOptionsGluster(gconf);
880      if (!ret) {
881          return ret;
882      }
883      g_free(s->logfile);
884      if (s->fd) {
885          glfs_close(s->fd);
886      }
887  
888      glfs_clear_preopened(s->glfs);
889  
890      return ret;
891  }
892  
893  static void qemu_gluster_refresh_limits(BlockDriverState *bs, Error **errp)
894  {
895      bs->bl.max_transfer = GLUSTER_MAX_TRANSFER;
896      bs->bl.max_pdiscard = MIN(SIZE_MAX, INT64_MAX);
897  }
898  
899  static int qemu_gluster_reopen_prepare(BDRVReopenState *state,
900                                         BlockReopenQueue *queue, Error **errp)
901  {
902      int ret = 0;
903      BDRVGlusterState *s;
904      BDRVGlusterReopenState *reop_s;
905      BlockdevOptionsGluster *gconf;
906      int open_flags = 0;
907  
908      assert(state != NULL);
909      assert(state->bs != NULL);
910  
911      s = state->bs->opaque;
912  
913      state->opaque = g_new0(BDRVGlusterReopenState, 1);
914      reop_s = state->opaque;
915  
916      qemu_gluster_parse_flags(state->flags, &open_flags);
917  
918      gconf = g_new0(BlockdevOptionsGluster, 1);
919      gconf->debug = s->debug;
920      gconf->has_debug = true;
921      gconf->logfile = g_strdup(s->logfile);
922  
923      /*
924       * If 'state->bs->exact_filename' is empty, 'state->options' should contain
925       * the JSON parameters already parsed.
926       */
927      if (state->bs->exact_filename[0] != '\0') {
928          reop_s->glfs = qemu_gluster_init(gconf, state->bs->exact_filename, NULL,
929                                           errp);
930      } else {
931          reop_s->glfs = qemu_gluster_init(gconf, NULL, state->options, errp);
932      }
933      if (reop_s->glfs == NULL) {
934          ret = -errno;
935          goto exit;
936      }
937  
938  #ifdef CONFIG_GLUSTERFS_XLATOR_OPT
939      ret = glfs_set_xlator_option(reop_s->glfs, "*-write-behind",
940                                   "resync-failed-syncs-after-fsync", "on");
941      if (ret < 0) {
942          error_setg_errno(errp, errno, "Unable to set xlator key/value pair");
943          ret = -errno;
944          goto exit;
945      }
946  #endif
947  
948      reop_s->fd = glfs_open(reop_s->glfs, gconf->path, open_flags);
949      if (reop_s->fd == NULL) {
950          /* reops->glfs will be cleaned up in _abort */
951          ret = -errno;
952          goto exit;
953      }
954  
955  exit:
956      /* state->opaque will be freed in either the _abort or _commit */
957      qapi_free_BlockdevOptionsGluster(gconf);
958      return ret;
959  }
960  
961  static void qemu_gluster_reopen_commit(BDRVReopenState *state)
962  {
963      BDRVGlusterReopenState *reop_s = state->opaque;
964      BDRVGlusterState *s = state->bs->opaque;
965  
966  
967      /* close the old */
968      if (s->fd) {
969          glfs_close(s->fd);
970      }
971  
972      glfs_clear_preopened(s->glfs);
973  
974      /* use the newly opened image / connection */
975      s->fd         = reop_s->fd;
976      s->glfs       = reop_s->glfs;
977  
978      g_free(state->opaque);
979      state->opaque = NULL;
980  
981      return;
982  }
983  
984  
985  static void qemu_gluster_reopen_abort(BDRVReopenState *state)
986  {
987      BDRVGlusterReopenState *reop_s = state->opaque;
988  
989      if (reop_s == NULL) {
990          return;
991      }
992  
993      if (reop_s->fd) {
994          glfs_close(reop_s->fd);
995      }
996  
997      glfs_clear_preopened(reop_s->glfs);
998  
999      g_free(state->opaque);
1000      state->opaque = NULL;
1001  
1002      return;
1003  }
1004  
1005  #ifdef CONFIG_GLUSTERFS_ZEROFILL
1006  static coroutine_fn int qemu_gluster_co_pwrite_zeroes(BlockDriverState *bs,
1007                                                        int64_t offset,
1008                                                        int64_t bytes,
1009                                                        BdrvRequestFlags flags)
1010  {
1011      int ret;
1012      GlusterAIOCB acb;
1013      BDRVGlusterState *s = bs->opaque;
1014  
1015      acb.size = bytes;
1016      acb.ret = 0;
1017      acb.coroutine = qemu_coroutine_self();
1018      acb.aio_context = bdrv_get_aio_context(bs);
1019  
1020      ret = glfs_zerofill_async(s->fd, offset, bytes, gluster_finish_aiocb, &acb);
1021      if (ret < 0) {
1022          return -errno;
1023      }
1024  
1025      qemu_coroutine_yield();
1026      return acb.ret;
1027  }
1028  #endif
1029  
1030  static int qemu_gluster_do_truncate(struct glfs_fd *fd, int64_t offset,
1031                                      PreallocMode prealloc, Error **errp)
1032  {
1033      int64_t current_length;
1034  
1035      current_length = glfs_lseek(fd, 0, SEEK_END);
1036      if (current_length < 0) {
1037          error_setg_errno(errp, errno, "Failed to determine current size");
1038          return -errno;
1039      }
1040  
1041      if (current_length > offset && prealloc != PREALLOC_MODE_OFF) {
1042          error_setg(errp, "Cannot use preallocation for shrinking files");
1043          return -ENOTSUP;
1044      }
1045  
1046      if (current_length == offset) {
1047          return 0;
1048      }
1049  
1050      switch (prealloc) {
1051  #ifdef CONFIG_GLUSTERFS_FALLOCATE
1052      case PREALLOC_MODE_FALLOC:
1053          if (glfs_fallocate(fd, 0, current_length, offset - current_length)) {
1054              error_setg_errno(errp, errno, "Could not preallocate data");
1055              return -errno;
1056          }
1057          break;
1058  #endif /* CONFIG_GLUSTERFS_FALLOCATE */
1059  #ifdef CONFIG_GLUSTERFS_ZEROFILL
1060      case PREALLOC_MODE_FULL:
1061          if (glfs_ftruncate(fd, offset)) {
1062              error_setg_errno(errp, errno, "Could not resize file");
1063              return -errno;
1064          }
1065          if (glfs_zerofill(fd, current_length, offset - current_length)) {
1066              error_setg_errno(errp, errno, "Could not zerofill the new area");
1067              return -errno;
1068          }
1069          break;
1070  #endif /* CONFIG_GLUSTERFS_ZEROFILL */
1071      case PREALLOC_MODE_OFF:
1072          if (glfs_ftruncate(fd, offset)) {
1073              error_setg_errno(errp, errno, "Could not resize file");
1074              return -errno;
1075          }
1076          break;
1077      default:
1078          error_setg(errp, "Unsupported preallocation mode: %s",
1079                     PreallocMode_str(prealloc));
1080          return -EINVAL;
1081      }
1082  
1083      return 0;
1084  }
1085  
1086  static int qemu_gluster_co_create(BlockdevCreateOptions *options,
1087                                    Error **errp)
1088  {
1089      BlockdevCreateOptionsGluster *opts = &options->u.gluster;
1090      struct glfs *glfs;
1091      struct glfs_fd *fd = NULL;
1092      int ret = 0;
1093  
1094      assert(options->driver == BLOCKDEV_DRIVER_GLUSTER);
1095  
1096      glfs = qemu_gluster_glfs_init(opts->location, errp);
1097      if (!glfs) {
1098          ret = -errno;
1099          goto out;
1100      }
1101  
1102      fd = glfs_creat(glfs, opts->location->path,
1103                      O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, S_IRUSR | S_IWUSR);
1104      if (!fd) {
1105          ret = -errno;
1106          goto out;
1107      }
1108  
1109      ret = qemu_gluster_do_truncate(fd, opts->size, opts->preallocation, errp);
1110  
1111  out:
1112      if (fd) {
1113          if (glfs_close(fd) != 0 && ret == 0) {
1114              ret = -errno;
1115          }
1116      }
1117      glfs_clear_preopened(glfs);
1118      return ret;
1119  }
1120  
1121  static int coroutine_fn qemu_gluster_co_create_opts(BlockDriver *drv,
1122                                                      const char *filename,
1123                                                      QemuOpts *opts,
1124                                                      Error **errp)
1125  {
1126      BlockdevCreateOptions *options;
1127      BlockdevCreateOptionsGluster *gopts;
1128      BlockdevOptionsGluster *gconf;
1129      char *tmp = NULL;
1130      Error *local_err = NULL;
1131      int ret;
1132  
1133      options = g_new0(BlockdevCreateOptions, 1);
1134      options->driver = BLOCKDEV_DRIVER_GLUSTER;
1135      gopts = &options->u.gluster;
1136  
1137      gconf = g_new0(BlockdevOptionsGluster, 1);
1138      gopts->location = gconf;
1139  
1140      gopts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
1141                             BDRV_SECTOR_SIZE);
1142  
1143      tmp = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
1144      gopts->preallocation = qapi_enum_parse(&PreallocMode_lookup, tmp,
1145                                             PREALLOC_MODE_OFF, &local_err);
1146      g_free(tmp);
1147      if (local_err) {
1148          error_propagate(errp, local_err);
1149          ret = -EINVAL;
1150          goto fail;
1151      }
1152  
1153      gconf->debug = qemu_opt_get_number_del(opts, GLUSTER_OPT_DEBUG,
1154                                             GLUSTER_DEBUG_DEFAULT);
1155      if (gconf->debug < 0) {
1156          gconf->debug = 0;
1157      } else if (gconf->debug > GLUSTER_DEBUG_MAX) {
1158          gconf->debug = GLUSTER_DEBUG_MAX;
1159      }
1160      gconf->has_debug = true;
1161  
1162      gconf->logfile = qemu_opt_get_del(opts, GLUSTER_OPT_LOGFILE);
1163      if (!gconf->logfile) {
1164          gconf->logfile = g_strdup(GLUSTER_LOGFILE_DEFAULT);
1165      }
1166  
1167      ret = qemu_gluster_parse(gconf, filename, NULL, errp);
1168      if (ret < 0) {
1169          goto fail;
1170      }
1171  
1172      ret = qemu_gluster_co_create(options, errp);
1173      if (ret < 0) {
1174          goto fail;
1175      }
1176  
1177      ret = 0;
1178  fail:
1179      qapi_free_BlockdevCreateOptions(options);
1180      return ret;
1181  }
1182  
1183  static coroutine_fn int qemu_gluster_co_rw(BlockDriverState *bs,
1184                                             int64_t sector_num, int nb_sectors,
1185                                             QEMUIOVector *qiov, int write)
1186  {
1187      int ret;
1188      GlusterAIOCB acb;
1189      BDRVGlusterState *s = bs->opaque;
1190      size_t size = nb_sectors * BDRV_SECTOR_SIZE;
1191      off_t offset = sector_num * BDRV_SECTOR_SIZE;
1192  
1193      acb.size = size;
1194      acb.ret = 0;
1195      acb.coroutine = qemu_coroutine_self();
1196      acb.aio_context = bdrv_get_aio_context(bs);
1197  
1198      if (write) {
1199          ret = glfs_pwritev_async(s->fd, qiov->iov, qiov->niov, offset, 0,
1200                                   gluster_finish_aiocb, &acb);
1201      } else {
1202          ret = glfs_preadv_async(s->fd, qiov->iov, qiov->niov, offset, 0,
1203                                  gluster_finish_aiocb, &acb);
1204      }
1205  
1206      if (ret < 0) {
1207          return -errno;
1208      }
1209  
1210      qemu_coroutine_yield();
1211      return acb.ret;
1212  }
1213  
1214  static coroutine_fn int qemu_gluster_co_truncate(BlockDriverState *bs,
1215                                                   int64_t offset,
1216                                                   bool exact,
1217                                                   PreallocMode prealloc,
1218                                                   BdrvRequestFlags flags,
1219                                                   Error **errp)
1220  {
1221      BDRVGlusterState *s = bs->opaque;
1222      return qemu_gluster_do_truncate(s->fd, offset, prealloc, errp);
1223  }
1224  
1225  static coroutine_fn int qemu_gluster_co_readv(BlockDriverState *bs,
1226                                                int64_t sector_num,
1227                                                int nb_sectors,
1228                                                QEMUIOVector *qiov)
1229  {
1230      return qemu_gluster_co_rw(bs, sector_num, nb_sectors, qiov, 0);
1231  }
1232  
1233  static coroutine_fn int qemu_gluster_co_writev(BlockDriverState *bs,
1234                                                 int64_t sector_num,
1235                                                 int nb_sectors,
1236                                                 QEMUIOVector *qiov,
1237                                                 int flags)
1238  {
1239      return qemu_gluster_co_rw(bs, sector_num, nb_sectors, qiov, 1);
1240  }
1241  
1242  static void qemu_gluster_close(BlockDriverState *bs)
1243  {
1244      BDRVGlusterState *s = bs->opaque;
1245  
1246      g_free(s->logfile);
1247      if (s->fd) {
1248          glfs_close(s->fd);
1249          s->fd = NULL;
1250      }
1251      glfs_clear_preopened(s->glfs);
1252  }
1253  
1254  static coroutine_fn int qemu_gluster_co_flush_to_disk(BlockDriverState *bs)
1255  {
1256      int ret;
1257      GlusterAIOCB acb;
1258      BDRVGlusterState *s = bs->opaque;
1259  
1260      acb.size = 0;
1261      acb.ret = 0;
1262      acb.coroutine = qemu_coroutine_self();
1263      acb.aio_context = bdrv_get_aio_context(bs);
1264  
1265      ret = glfs_fsync_async(s->fd, gluster_finish_aiocb, &acb);
1266      if (ret < 0) {
1267          ret = -errno;
1268          goto error;
1269      }
1270  
1271      qemu_coroutine_yield();
1272      if (acb.ret < 0) {
1273          ret = acb.ret;
1274          goto error;
1275      }
1276  
1277      return acb.ret;
1278  
1279  error:
1280      /* Some versions of Gluster (3.5.6 -> 3.5.8?) will not retain its cache
1281       * after a fsync failure, so we have no way of allowing the guest to safely
1282       * continue.  Gluster versions prior to 3.5.6 don't retain the cache
1283       * either, but will invalidate the fd on error, so this is again our only
1284       * option.
1285       *
1286       * The 'resync-failed-syncs-after-fsync' xlator option for the
1287       * write-behind cache will cause later gluster versions to retain its
1288       * cache after error, so long as the fd remains open.  However, we
1289       * currently have no way of knowing if this option is supported.
1290       *
1291       * TODO: Once gluster provides a way for us to determine if the option
1292       * is supported, bypass the closure and setting drv to NULL.  */
1293      qemu_gluster_close(bs);
1294      bs->drv = NULL;
1295      return ret;
1296  }
1297  
1298  #ifdef CONFIG_GLUSTERFS_DISCARD
1299  static coroutine_fn int qemu_gluster_co_pdiscard(BlockDriverState *bs,
1300                                                   int64_t offset, int64_t bytes)
1301  {
1302      int ret;
1303      GlusterAIOCB acb;
1304      BDRVGlusterState *s = bs->opaque;
1305  
1306      assert(bytes <= SIZE_MAX); /* rely on max_pdiscard */
1307  
1308      acb.size = 0;
1309      acb.ret = 0;
1310      acb.coroutine = qemu_coroutine_self();
1311      acb.aio_context = bdrv_get_aio_context(bs);
1312  
1313      ret = glfs_discard_async(s->fd, offset, bytes, gluster_finish_aiocb, &acb);
1314      if (ret < 0) {
1315          return -errno;
1316      }
1317  
1318      qemu_coroutine_yield();
1319      return acb.ret;
1320  }
1321  #endif
1322  
1323  static int64_t coroutine_fn qemu_gluster_co_getlength(BlockDriverState *bs)
1324  {
1325      BDRVGlusterState *s = bs->opaque;
1326      int64_t ret;
1327  
1328      ret = glfs_lseek(s->fd, 0, SEEK_END);
1329      if (ret < 0) {
1330          return -errno;
1331      } else {
1332          return ret;
1333      }
1334  }
1335  
1336  static int64_t coroutine_fn
1337  qemu_gluster_co_get_allocated_file_size(BlockDriverState *bs)
1338  {
1339      BDRVGlusterState *s = bs->opaque;
1340      struct stat st;
1341      int ret;
1342  
1343      ret = glfs_fstat(s->fd, &st);
1344      if (ret < 0) {
1345          return -errno;
1346      } else {
1347          return st.st_blocks * 512;
1348      }
1349  }
1350  
1351  /*
1352   * Find allocation range in @bs around offset @start.
1353   * May change underlying file descriptor's file offset.
1354   * If @start is not in a hole, store @start in @data, and the
1355   * beginning of the next hole in @hole, and return 0.
1356   * If @start is in a non-trailing hole, store @start in @hole and the
1357   * beginning of the next non-hole in @data, and return 0.
1358   * If @start is in a trailing hole or beyond EOF, return -ENXIO.
1359   * If we can't find out, return a negative errno other than -ENXIO.
1360   *
1361   * (Shamefully copied from file-posix.c, only minuscule adaptions.)
1362   */
1363  static int find_allocation(BlockDriverState *bs, off_t start,
1364                             off_t *data, off_t *hole)
1365  {
1366      BDRVGlusterState *s = bs->opaque;
1367  
1368      if (!s->supports_seek_data) {
1369          goto exit;
1370      }
1371  
1372  #if defined SEEK_HOLE && defined SEEK_DATA
1373      off_t offs;
1374  
1375      /*
1376       * SEEK_DATA cases:
1377       * D1. offs == start: start is in data
1378       * D2. offs > start: start is in a hole, next data at offs
1379       * D3. offs < 0, errno = ENXIO: either start is in a trailing hole
1380       *                              or start is beyond EOF
1381       *     If the latter happens, the file has been truncated behind
1382       *     our back since we opened it.  All bets are off then.
1383       *     Treating like a trailing hole is simplest.
1384       * D4. offs < 0, errno != ENXIO: we learned nothing
1385       */
1386      offs = glfs_lseek(s->fd, start, SEEK_DATA);
1387      if (offs < 0) {
1388          return -errno;          /* D3 or D4 */
1389      }
1390  
1391      if (offs < start) {
1392          /* This is not a valid return by lseek().  We are safe to just return
1393           * -EIO in this case, and we'll treat it like D4. Unfortunately some
1394           *  versions of gluster server will return offs < start, so an assert
1395           *  here will unnecessarily abort QEMU. */
1396          return -EIO;
1397      }
1398  
1399      if (offs > start) {
1400          /* D2: in hole, next data at offs */
1401          *hole = start;
1402          *data = offs;
1403          return 0;
1404      }
1405  
1406      /* D1: in data, end not yet known */
1407  
1408      /*
1409       * SEEK_HOLE cases:
1410       * H1. offs == start: start is in a hole
1411       *     If this happens here, a hole has been dug behind our back
1412       *     since the previous lseek().
1413       * H2. offs > start: either start is in data, next hole at offs,
1414       *                   or start is in trailing hole, EOF at offs
1415       *     Linux treats trailing holes like any other hole: offs ==
1416       *     start.  Solaris seeks to EOF instead: offs > start (blech).
1417       *     If that happens here, a hole has been dug behind our back
1418       *     since the previous lseek().
1419       * H3. offs < 0, errno = ENXIO: start is beyond EOF
1420       *     If this happens, the file has been truncated behind our
1421       *     back since we opened it.  Treat it like a trailing hole.
1422       * H4. offs < 0, errno != ENXIO: we learned nothing
1423       *     Pretend we know nothing at all, i.e. "forget" about D1.
1424       */
1425      offs = glfs_lseek(s->fd, start, SEEK_HOLE);
1426      if (offs < 0) {
1427          return -errno;          /* D1 and (H3 or H4) */
1428      }
1429  
1430      if (offs < start) {
1431          /* This is not a valid return by lseek().  We are safe to just return
1432           * -EIO in this case, and we'll treat it like H4. Unfortunately some
1433           *  versions of gluster server will return offs < start, so an assert
1434           *  here will unnecessarily abort QEMU. */
1435          return -EIO;
1436      }
1437  
1438      if (offs > start) {
1439          /*
1440           * D1 and H2: either in data, next hole at offs, or it was in
1441           * data but is now in a trailing hole.  In the latter case,
1442           * all bets are off.  Treating it as if it there was data all
1443           * the way to EOF is safe, so simply do that.
1444           */
1445          *data = start;
1446          *hole = offs;
1447          return 0;
1448      }
1449  
1450      /* D1 and H1 */
1451      return -EBUSY;
1452  #endif
1453  
1454  exit:
1455      return -ENOTSUP;
1456  }
1457  
1458  /*
1459   * Returns the allocation status of the specified offset.
1460   *
1461   * The block layer guarantees 'offset' and 'bytes' are within bounds.
1462   *
1463   * 'pnum' is set to the number of bytes (including and immediately following
1464   * the specified offset) that are known to be in the same
1465   * allocated/unallocated state.
1466   *
1467   * 'bytes' is a soft cap for 'pnum'.  If the information is free, 'pnum' may
1468   * well exceed it.
1469   *
1470   * (Based on raw_co_block_status() from file-posix.c.)
1471   */
1472  static int coroutine_fn qemu_gluster_co_block_status(BlockDriverState *bs,
1473                                                       bool want_zero,
1474                                                       int64_t offset,
1475                                                       int64_t bytes,
1476                                                       int64_t *pnum,
1477                                                       int64_t *map,
1478                                                       BlockDriverState **file)
1479  {
1480      BDRVGlusterState *s = bs->opaque;
1481      off_t data = 0, hole = 0;
1482      int ret = -EINVAL;
1483  
1484      assert(QEMU_IS_ALIGNED(offset | bytes, bs->bl.request_alignment));
1485  
1486      if (!s->fd) {
1487          return ret;
1488      }
1489  
1490      if (!want_zero) {
1491          *pnum = bytes;
1492          *map = offset;
1493          *file = bs;
1494          return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
1495      }
1496  
1497      ret = find_allocation(bs, offset, &data, &hole);
1498      if (ret == -ENXIO) {
1499          /* Trailing hole */
1500          *pnum = bytes;
1501          ret = BDRV_BLOCK_ZERO;
1502      } else if (ret < 0) {
1503          /* No info available, so pretend there are no holes */
1504          *pnum = bytes;
1505          ret = BDRV_BLOCK_DATA;
1506      } else if (data == offset) {
1507          /* On a data extent, compute bytes to the end of the extent,
1508           * possibly including a partial sector at EOF. */
1509          *pnum = hole - offset;
1510  
1511          /*
1512           * We are not allowed to return partial sectors, though, so
1513           * round up if necessary.
1514           */
1515          if (!QEMU_IS_ALIGNED(*pnum, bs->bl.request_alignment)) {
1516              int64_t file_length = qemu_gluster_co_getlength(bs);
1517              if (file_length > 0) {
1518                  /* Ignore errors, this is just a safeguard */
1519                  assert(hole == file_length);
1520              }
1521              *pnum = ROUND_UP(*pnum, bs->bl.request_alignment);
1522          }
1523  
1524          ret = BDRV_BLOCK_DATA;
1525      } else {
1526          /* On a hole, compute bytes to the beginning of the next extent.  */
1527          assert(hole == offset);
1528          *pnum = data - offset;
1529          ret = BDRV_BLOCK_ZERO;
1530      }
1531  
1532      *map = offset;
1533      *file = bs;
1534  
1535      return ret | BDRV_BLOCK_OFFSET_VALID;
1536  }
1537  
1538  
1539  static const char *const gluster_strong_open_opts[] = {
1540      GLUSTER_OPT_VOLUME,
1541      GLUSTER_OPT_PATH,
1542      GLUSTER_OPT_TYPE,
1543      GLUSTER_OPT_SERVER_PATTERN,
1544      GLUSTER_OPT_HOST,
1545      GLUSTER_OPT_PORT,
1546      GLUSTER_OPT_TO,
1547      GLUSTER_OPT_IPV4,
1548      GLUSTER_OPT_IPV6,
1549      GLUSTER_OPT_SOCKET,
1550  
1551      NULL
1552  };
1553  
1554  static BlockDriver bdrv_gluster = {
1555      .format_name                  = "gluster",
1556      .protocol_name                = "gluster",
1557      .instance_size                = sizeof(BDRVGlusterState),
1558      .bdrv_file_open               = qemu_gluster_open,
1559      .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
1560      .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
1561      .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
1562      .bdrv_close                   = qemu_gluster_close,
1563      .bdrv_co_create               = qemu_gluster_co_create,
1564      .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
1565      .bdrv_co_getlength            = qemu_gluster_co_getlength,
1566      .bdrv_co_get_allocated_file_size = qemu_gluster_co_get_allocated_file_size,
1567      .bdrv_co_truncate             = qemu_gluster_co_truncate,
1568      .bdrv_co_readv                = qemu_gluster_co_readv,
1569      .bdrv_co_writev               = qemu_gluster_co_writev,
1570      .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
1571  #ifdef CONFIG_GLUSTERFS_DISCARD
1572      .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
1573  #endif
1574  #ifdef CONFIG_GLUSTERFS_ZEROFILL
1575      .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
1576  #endif
1577      .bdrv_co_block_status         = qemu_gluster_co_block_status,
1578      .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
1579      .create_opts                  = &qemu_gluster_create_opts,
1580      .strong_runtime_opts          = gluster_strong_open_opts,
1581  };
1582  
1583  static BlockDriver bdrv_gluster_tcp = {
1584      .format_name                  = "gluster",
1585      .protocol_name                = "gluster+tcp",
1586      .instance_size                = sizeof(BDRVGlusterState),
1587      .bdrv_file_open               = qemu_gluster_open,
1588      .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
1589      .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
1590      .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
1591      .bdrv_close                   = qemu_gluster_close,
1592      .bdrv_co_create               = qemu_gluster_co_create,
1593      .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
1594      .bdrv_co_getlength            = qemu_gluster_co_getlength,
1595      .bdrv_co_get_allocated_file_size = qemu_gluster_co_get_allocated_file_size,
1596      .bdrv_co_truncate             = qemu_gluster_co_truncate,
1597      .bdrv_co_readv                = qemu_gluster_co_readv,
1598      .bdrv_co_writev               = qemu_gluster_co_writev,
1599      .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
1600  #ifdef CONFIG_GLUSTERFS_DISCARD
1601      .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
1602  #endif
1603  #ifdef CONFIG_GLUSTERFS_ZEROFILL
1604      .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
1605  #endif
1606      .bdrv_co_block_status         = qemu_gluster_co_block_status,
1607      .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
1608      .create_opts                  = &qemu_gluster_create_opts,
1609      .strong_runtime_opts          = gluster_strong_open_opts,
1610  };
1611  
1612  static BlockDriver bdrv_gluster_unix = {
1613      .format_name                  = "gluster",
1614      .protocol_name                = "gluster+unix",
1615      .instance_size                = sizeof(BDRVGlusterState),
1616      .bdrv_file_open               = qemu_gluster_open,
1617      .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
1618      .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
1619      .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
1620      .bdrv_close                   = qemu_gluster_close,
1621      .bdrv_co_create               = qemu_gluster_co_create,
1622      .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
1623      .bdrv_co_getlength            = qemu_gluster_co_getlength,
1624      .bdrv_co_get_allocated_file_size = qemu_gluster_co_get_allocated_file_size,
1625      .bdrv_co_truncate             = qemu_gluster_co_truncate,
1626      .bdrv_co_readv                = qemu_gluster_co_readv,
1627      .bdrv_co_writev               = qemu_gluster_co_writev,
1628      .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
1629  #ifdef CONFIG_GLUSTERFS_DISCARD
1630      .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
1631  #endif
1632  #ifdef CONFIG_GLUSTERFS_ZEROFILL
1633      .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
1634  #endif
1635      .bdrv_co_block_status         = qemu_gluster_co_block_status,
1636      .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
1637      .create_opts                  = &qemu_gluster_create_opts,
1638      .strong_runtime_opts          = gluster_strong_open_opts,
1639  };
1640  
1641  /* rdma is deprecated (actually never supported for volfile fetch).
1642   * Let's maintain it for the protocol compatibility, to make sure things
1643   * won't break immediately. For now, gluster+rdma will fall back to gluster+tcp
1644   * protocol with a warning.
1645   * TODO: remove gluster+rdma interface support
1646   */
1647  static BlockDriver bdrv_gluster_rdma = {
1648      .format_name                  = "gluster",
1649      .protocol_name                = "gluster+rdma",
1650      .instance_size                = sizeof(BDRVGlusterState),
1651      .bdrv_file_open               = qemu_gluster_open,
1652      .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
1653      .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
1654      .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
1655      .bdrv_close                   = qemu_gluster_close,
1656      .bdrv_co_create               = qemu_gluster_co_create,
1657      .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
1658      .bdrv_co_getlength            = qemu_gluster_co_getlength,
1659      .bdrv_co_get_allocated_file_size = qemu_gluster_co_get_allocated_file_size,
1660      .bdrv_co_truncate             = qemu_gluster_co_truncate,
1661      .bdrv_co_readv                = qemu_gluster_co_readv,
1662      .bdrv_co_writev               = qemu_gluster_co_writev,
1663      .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
1664  #ifdef CONFIG_GLUSTERFS_DISCARD
1665      .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
1666  #endif
1667  #ifdef CONFIG_GLUSTERFS_ZEROFILL
1668      .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
1669  #endif
1670      .bdrv_co_block_status         = qemu_gluster_co_block_status,
1671      .bdrv_refresh_limits          = qemu_gluster_refresh_limits,
1672      .create_opts                  = &qemu_gluster_create_opts,
1673      .strong_runtime_opts          = gluster_strong_open_opts,
1674  };
1675  
1676  static void bdrv_gluster_init(void)
1677  {
1678      bdrv_register(&bdrv_gluster_rdma);
1679      bdrv_register(&bdrv_gluster_unix);
1680      bdrv_register(&bdrv_gluster_tcp);
1681      bdrv_register(&bdrv_gluster);
1682  }
1683  
1684  block_init(bdrv_gluster_init);
1685