xref: /openbmc/qemu/block/gluster.c (revision 438c78da)
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 <glusterfs/api/glfs.h>
13 #include "block/block_int.h"
14 #include "block/qdict.h"
15 #include "qapi/error.h"
16 #include "qapi/qmp/qdict.h"
17 #include "qapi/qmp/qerror.h"
18 #include "qemu/uri.h"
19 #include "qemu/error-report.h"
20 #include "qemu/option.h"
21 #include "qemu/cutils.h"
22 
23 #define GLUSTER_OPT_FILENAME        "filename"
24 #define GLUSTER_OPT_VOLUME          "volume"
25 #define GLUSTER_OPT_PATH            "path"
26 #define GLUSTER_OPT_TYPE            "type"
27 #define GLUSTER_OPT_SERVER_PATTERN  "server."
28 #define GLUSTER_OPT_HOST            "host"
29 #define GLUSTER_OPT_PORT            "port"
30 #define GLUSTER_OPT_TO              "to"
31 #define GLUSTER_OPT_IPV4            "ipv4"
32 #define GLUSTER_OPT_IPV6            "ipv6"
33 #define GLUSTER_OPT_SOCKET          "socket"
34 #define GLUSTER_OPT_DEBUG           "debug"
35 #define GLUSTER_DEFAULT_PORT        24007
36 #define GLUSTER_DEBUG_DEFAULT       4
37 #define GLUSTER_DEBUG_MAX           9
38 #define GLUSTER_OPT_LOGFILE         "logfile"
39 #define GLUSTER_LOGFILE_DEFAULT     "-" /* handled in libgfapi as /dev/stderr */
40 
41 #define GERR_INDEX_HINT "hint: check in 'server' array index '%d'\n"
42 
43 typedef struct GlusterAIOCB {
44     int64_t size;
45     int ret;
46     Coroutine *coroutine;
47     AioContext *aio_context;
48 } GlusterAIOCB;
49 
50 typedef struct BDRVGlusterState {
51     struct glfs *glfs;
52     struct glfs_fd *fd;
53     char *logfile;
54     bool supports_seek_data;
55     int debug;
56 } BDRVGlusterState;
57 
58 typedef struct BDRVGlusterReopenState {
59     struct glfs *glfs;
60     struct glfs_fd *fd;
61 } BDRVGlusterReopenState;
62 
63 
64 typedef struct GlfsPreopened {
65     char *volume;
66     glfs_t *fs;
67     int ref;
68 } GlfsPreopened;
69 
70 typedef struct ListElement {
71     QLIST_ENTRY(ListElement) list;
72     GlfsPreopened saved;
73 } ListElement;
74 
75 static QLIST_HEAD(glfs_list, ListElement) glfs_list;
76 
77 static QemuOptsList qemu_gluster_create_opts = {
78     .name = "qemu-gluster-create-opts",
79     .head = QTAILQ_HEAD_INITIALIZER(qemu_gluster_create_opts.head),
80     .desc = {
81         {
82             .name = BLOCK_OPT_SIZE,
83             .type = QEMU_OPT_SIZE,
84             .help = "Virtual disk size"
85         },
86         {
87             .name = BLOCK_OPT_PREALLOC,
88             .type = QEMU_OPT_STRING,
89             .help = "Preallocation mode (allowed values: off, full)"
90         },
91         {
92             .name = GLUSTER_OPT_DEBUG,
93             .type = QEMU_OPT_NUMBER,
94             .help = "Gluster log level, valid range is 0-9",
95         },
96         {
97             .name = GLUSTER_OPT_LOGFILE,
98             .type = QEMU_OPT_STRING,
99             .help = "Logfile path of libgfapi",
100         },
101         { /* end of list */ }
102     }
103 };
104 
105 static QemuOptsList runtime_opts = {
106     .name = "gluster",
107     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
108     .desc = {
109         {
110             .name = GLUSTER_OPT_FILENAME,
111             .type = QEMU_OPT_STRING,
112             .help = "URL to the gluster image",
113         },
114         {
115             .name = GLUSTER_OPT_DEBUG,
116             .type = QEMU_OPT_NUMBER,
117             .help = "Gluster log level, valid range is 0-9",
118         },
119         {
120             .name = GLUSTER_OPT_LOGFILE,
121             .type = QEMU_OPT_STRING,
122             .help = "Logfile path of libgfapi",
123         },
124         { /* end of list */ }
125     },
126 };
127 
128 static QemuOptsList runtime_json_opts = {
129     .name = "gluster_json",
130     .head = QTAILQ_HEAD_INITIALIZER(runtime_json_opts.head),
131     .desc = {
132         {
133             .name = GLUSTER_OPT_VOLUME,
134             .type = QEMU_OPT_STRING,
135             .help = "name of gluster volume where VM image resides",
136         },
137         {
138             .name = GLUSTER_OPT_PATH,
139             .type = QEMU_OPT_STRING,
140             .help = "absolute path to image file in gluster volume",
141         },
142         {
143             .name = GLUSTER_OPT_DEBUG,
144             .type = QEMU_OPT_NUMBER,
145             .help = "Gluster log level, valid range is 0-9",
146         },
147         { /* end of list */ }
148     },
149 };
150 
151 static QemuOptsList runtime_type_opts = {
152     .name = "gluster_type",
153     .head = QTAILQ_HEAD_INITIALIZER(runtime_type_opts.head),
154     .desc = {
155         {
156             .name = GLUSTER_OPT_TYPE,
157             .type = QEMU_OPT_STRING,
158             .help = "inet|unix",
159         },
160         { /* end of list */ }
161     },
162 };
163 
164 static QemuOptsList runtime_unix_opts = {
165     .name = "gluster_unix",
166     .head = QTAILQ_HEAD_INITIALIZER(runtime_unix_opts.head),
167     .desc = {
168         {
169             .name = GLUSTER_OPT_SOCKET,
170             .type = QEMU_OPT_STRING,
171             .help = "socket file path (legacy)",
172         },
173         {
174             .name = GLUSTER_OPT_PATH,
175             .type = QEMU_OPT_STRING,
176             .help = "socket file path (QAPI)",
177         },
178         { /* end of list */ }
179     },
180 };
181 
182 static QemuOptsList runtime_inet_opts = {
183     .name = "gluster_inet",
184     .head = QTAILQ_HEAD_INITIALIZER(runtime_inet_opts.head),
185     .desc = {
186         {
187             .name = GLUSTER_OPT_TYPE,
188             .type = QEMU_OPT_STRING,
189             .help = "inet|unix",
190         },
191         {
192             .name = GLUSTER_OPT_HOST,
193             .type = QEMU_OPT_STRING,
194             .help = "host address (hostname/ipv4/ipv6 addresses)",
195         },
196         {
197             .name = GLUSTER_OPT_PORT,
198             .type = QEMU_OPT_STRING,
199             .help = "port number on which glusterd is listening (default 24007)",
200         },
201         {
202             .name = "to",
203             .type = QEMU_OPT_NUMBER,
204             .help = "max port number, not supported by gluster",
205         },
206         {
207             .name = "ipv4",
208             .type = QEMU_OPT_BOOL,
209             .help = "ipv4 bool value, not supported by gluster",
210         },
211         {
212             .name = "ipv6",
213             .type = QEMU_OPT_BOOL,
214             .help = "ipv6 bool value, not supported by gluster",
215         },
216         { /* end of list */ }
217     },
218 };
219 
220 static void glfs_set_preopened(const char *volume, glfs_t *fs)
221 {
222     ListElement *entry = NULL;
223 
224     entry = g_new(ListElement, 1);
225 
226     entry->saved.volume = g_strdup(volume);
227 
228     entry->saved.fs = fs;
229     entry->saved.ref = 1;
230 
231     QLIST_INSERT_HEAD(&glfs_list, entry, list);
232 }
233 
234 static glfs_t *glfs_find_preopened(const char *volume)
235 {
236     ListElement *entry = NULL;
237 
238      QLIST_FOREACH(entry, &glfs_list, list) {
239         if (strcmp(entry->saved.volume, volume) == 0) {
240             entry->saved.ref++;
241             return entry->saved.fs;
242         }
243      }
244 
245     return NULL;
246 }
247 
248 static void glfs_clear_preopened(glfs_t *fs)
249 {
250     ListElement *entry = NULL;
251     ListElement *next;
252 
253     if (fs == NULL) {
254         return;
255     }
256 
257     QLIST_FOREACH_SAFE(entry, &glfs_list, list, next) {
258         if (entry->saved.fs == fs) {
259             if (--entry->saved.ref) {
260                 return;
261             }
262 
263             QLIST_REMOVE(entry, list);
264 
265             glfs_fini(entry->saved.fs);
266             g_free(entry->saved.volume);
267             g_free(entry);
268         }
269     }
270 }
271 
272 static int parse_volume_options(BlockdevOptionsGluster *gconf, char *path)
273 {
274     char *p, *q;
275 
276     if (!path) {
277         return -EINVAL;
278     }
279 
280     /* volume */
281     p = q = path + strspn(path, "/");
282     p += strcspn(p, "/");
283     if (*p == '\0') {
284         return -EINVAL;
285     }
286     gconf->volume = g_strndup(q, p - q);
287 
288     /* path */
289     p += strspn(p, "/");
290     if (*p == '\0') {
291         return -EINVAL;
292     }
293     gconf->path = g_strdup(p);
294     return 0;
295 }
296 
297 /*
298  * file=gluster[+transport]://[host[:port]]/volume/path[?socket=...]
299  *
300  * 'gluster' is the protocol.
301  *
302  * 'transport' specifies the transport type used to connect to gluster
303  * management daemon (glusterd). Valid transport types are
304  * tcp or unix. If a transport type isn't specified, then tcp type is assumed.
305  *
306  * 'host' specifies the host where the volume file specification for
307  * the given volume resides. This can be either hostname or ipv4 address.
308  * If transport type is 'unix', then 'host' field should not be specified.
309  * The 'socket' field needs to be populated with the path to unix domain
310  * socket.
311  *
312  * 'port' is the port number on which glusterd is listening. This is optional
313  * and if not specified, QEMU will send 0 which will make gluster to use the
314  * default port. If the transport type is unix, then 'port' should not be
315  * specified.
316  *
317  * 'volume' is the name of the gluster volume which contains the VM image.
318  *
319  * 'path' is the path to the actual VM image that resides on gluster volume.
320  *
321  * Examples:
322  *
323  * file=gluster://1.2.3.4/testvol/a.img
324  * file=gluster+tcp://1.2.3.4/testvol/a.img
325  * file=gluster+tcp://1.2.3.4:24007/testvol/dir/a.img
326  * file=gluster+tcp://host.domain.com:24007/testvol/dir/a.img
327  * file=gluster+unix:///testvol/dir/a.img?socket=/tmp/glusterd.socket
328  */
329 static int qemu_gluster_parse_uri(BlockdevOptionsGluster *gconf,
330                                   const char *filename)
331 {
332     SocketAddress *gsconf;
333     URI *uri;
334     QueryParams *qp = NULL;
335     bool is_unix = false;
336     int ret = 0;
337 
338     uri = uri_parse(filename);
339     if (!uri) {
340         return -EINVAL;
341     }
342 
343     gconf->server = g_new0(SocketAddressList, 1);
344     gconf->server->value = gsconf = g_new0(SocketAddress, 1);
345 
346     /* transport */
347     if (!uri->scheme || !strcmp(uri->scheme, "gluster")) {
348         gsconf->type = SOCKET_ADDRESS_TYPE_INET;
349     } else if (!strcmp(uri->scheme, "gluster+tcp")) {
350         gsconf->type = SOCKET_ADDRESS_TYPE_INET;
351     } else if (!strcmp(uri->scheme, "gluster+unix")) {
352         gsconf->type = SOCKET_ADDRESS_TYPE_UNIX;
353         is_unix = true;
354     } else if (!strcmp(uri->scheme, "gluster+rdma")) {
355         gsconf->type = SOCKET_ADDRESS_TYPE_INET;
356         warn_report("rdma feature is not supported, falling back to tcp");
357     } else {
358         ret = -EINVAL;
359         goto out;
360     }
361 
362     ret = parse_volume_options(gconf, uri->path);
363     if (ret < 0) {
364         goto out;
365     }
366 
367     qp = query_params_parse(uri->query);
368     if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
369         ret = -EINVAL;
370         goto out;
371     }
372 
373     if (is_unix) {
374         if (uri->server || uri->port) {
375             ret = -EINVAL;
376             goto out;
377         }
378         if (strcmp(qp->p[0].name, "socket")) {
379             ret = -EINVAL;
380             goto out;
381         }
382         gsconf->u.q_unix.path = g_strdup(qp->p[0].value);
383     } else {
384         gsconf->u.inet.host = g_strdup(uri->server ? uri->server : "localhost");
385         if (uri->port) {
386             gsconf->u.inet.port = g_strdup_printf("%d", uri->port);
387         } else {
388             gsconf->u.inet.port = g_strdup_printf("%d", GLUSTER_DEFAULT_PORT);
389         }
390     }
391 
392 out:
393     if (qp) {
394         query_params_free(qp);
395     }
396     uri_free(uri);
397     return ret;
398 }
399 
400 static struct glfs *qemu_gluster_glfs_init(BlockdevOptionsGluster *gconf,
401                                            Error **errp)
402 {
403     struct glfs *glfs;
404     int ret;
405     int old_errno;
406     SocketAddressList *server;
407     unsigned long long port;
408 
409     glfs = glfs_find_preopened(gconf->volume);
410     if (glfs) {
411         return glfs;
412     }
413 
414     glfs = glfs_new(gconf->volume);
415     if (!glfs) {
416         goto out;
417     }
418 
419     glfs_set_preopened(gconf->volume, glfs);
420 
421     for (server = gconf->server; server; server = server->next) {
422         switch (server->value->type) {
423         case SOCKET_ADDRESS_TYPE_UNIX:
424             ret = glfs_set_volfile_server(glfs, "unix",
425                                    server->value->u.q_unix.path, 0);
426             break;
427         case SOCKET_ADDRESS_TYPE_INET:
428             if (parse_uint_full(server->value->u.inet.port, &port, 10) < 0 ||
429                 port > 65535) {
430                 error_setg(errp, "'%s' is not a valid port number",
431                            server->value->u.inet.port);
432                 errno = EINVAL;
433                 goto out;
434             }
435             ret = glfs_set_volfile_server(glfs, "tcp",
436                                    server->value->u.inet.host,
437                                    (int)port);
438             break;
439         case SOCKET_ADDRESS_TYPE_VSOCK:
440         case SOCKET_ADDRESS_TYPE_FD:
441         default:
442             abort();
443         }
444 
445         if (ret < 0) {
446             goto out;
447         }
448     }
449 
450     ret = glfs_set_logging(glfs, gconf->logfile, gconf->debug);
451     if (ret < 0) {
452         goto out;
453     }
454 
455     ret = glfs_init(glfs);
456     if (ret) {
457         error_setg(errp, "Gluster connection for volume %s, path %s failed"
458                          " to connect", gconf->volume, gconf->path);
459         for (server = gconf->server; server; server = server->next) {
460             if (server->value->type  == SOCKET_ADDRESS_TYPE_UNIX) {
461                 error_append_hint(errp, "hint: failed on socket %s ",
462                                   server->value->u.q_unix.path);
463             } else {
464                 error_append_hint(errp, "hint: failed on host %s and port %s ",
465                                   server->value->u.inet.host,
466                                   server->value->u.inet.port);
467             }
468         }
469 
470         error_append_hint(errp, "Please refer to gluster logs for more info\n");
471 
472         /* glfs_init sometimes doesn't set errno although docs suggest that */
473         if (errno == 0) {
474             errno = EINVAL;
475         }
476 
477         goto out;
478     }
479     return glfs;
480 
481 out:
482     if (glfs) {
483         old_errno = errno;
484         glfs_clear_preopened(glfs);
485         errno = old_errno;
486     }
487     return NULL;
488 }
489 
490 /*
491  * Convert the json formatted command line into qapi.
492 */
493 static int qemu_gluster_parse_json(BlockdevOptionsGluster *gconf,
494                                   QDict *options, Error **errp)
495 {
496     QemuOpts *opts;
497     SocketAddress *gsconf = NULL;
498     SocketAddressList *curr = NULL;
499     QDict *backing_options = NULL;
500     Error *local_err = NULL;
501     char *str = NULL;
502     const char *ptr;
503     int i, type, num_servers;
504 
505     /* create opts info from runtime_json_opts list */
506     opts = qemu_opts_create(&runtime_json_opts, NULL, 0, &error_abort);
507     qemu_opts_absorb_qdict(opts, options, &local_err);
508     if (local_err) {
509         goto out;
510     }
511 
512     num_servers = qdict_array_entries(options, GLUSTER_OPT_SERVER_PATTERN);
513     if (num_servers < 1) {
514         error_setg(&local_err, QERR_MISSING_PARAMETER, "server");
515         goto out;
516     }
517 
518     ptr = qemu_opt_get(opts, GLUSTER_OPT_VOLUME);
519     if (!ptr) {
520         error_setg(&local_err, QERR_MISSING_PARAMETER, GLUSTER_OPT_VOLUME);
521         goto out;
522     }
523     gconf->volume = g_strdup(ptr);
524 
525     ptr = qemu_opt_get(opts, GLUSTER_OPT_PATH);
526     if (!ptr) {
527         error_setg(&local_err, QERR_MISSING_PARAMETER, GLUSTER_OPT_PATH);
528         goto out;
529     }
530     gconf->path = g_strdup(ptr);
531     qemu_opts_del(opts);
532 
533     for (i = 0; i < num_servers; i++) {
534         str = g_strdup_printf(GLUSTER_OPT_SERVER_PATTERN"%d.", i);
535         qdict_extract_subqdict(options, &backing_options, str);
536 
537         /* create opts info from runtime_type_opts list */
538         opts = qemu_opts_create(&runtime_type_opts, NULL, 0, &error_abort);
539         qemu_opts_absorb_qdict(opts, backing_options, &local_err);
540         if (local_err) {
541             goto out;
542         }
543 
544         ptr = qemu_opt_get(opts, GLUSTER_OPT_TYPE);
545         if (!ptr) {
546             error_setg(&local_err, QERR_MISSING_PARAMETER, GLUSTER_OPT_TYPE);
547             error_append_hint(&local_err, GERR_INDEX_HINT, i);
548             goto out;
549 
550         }
551         gsconf = g_new0(SocketAddress, 1);
552         if (!strcmp(ptr, "tcp")) {
553             ptr = "inet";       /* accept legacy "tcp" */
554         }
555         type = qapi_enum_parse(&SocketAddressType_lookup, ptr, -1, NULL);
556         if (type != SOCKET_ADDRESS_TYPE_INET
557             && type != SOCKET_ADDRESS_TYPE_UNIX) {
558             error_setg(&local_err,
559                        "Parameter '%s' may be 'inet' or 'unix'",
560                        GLUSTER_OPT_TYPE);
561             error_append_hint(&local_err, GERR_INDEX_HINT, i);
562             goto out;
563         }
564         gsconf->type = type;
565         qemu_opts_del(opts);
566 
567         if (gsconf->type == SOCKET_ADDRESS_TYPE_INET) {
568             /* create opts info from runtime_inet_opts list */
569             opts = qemu_opts_create(&runtime_inet_opts, NULL, 0, &error_abort);
570             qemu_opts_absorb_qdict(opts, backing_options, &local_err);
571             if (local_err) {
572                 goto out;
573             }
574 
575             ptr = qemu_opt_get(opts, GLUSTER_OPT_HOST);
576             if (!ptr) {
577                 error_setg(&local_err, QERR_MISSING_PARAMETER,
578                            GLUSTER_OPT_HOST);
579                 error_append_hint(&local_err, GERR_INDEX_HINT, i);
580                 goto out;
581             }
582             gsconf->u.inet.host = g_strdup(ptr);
583             ptr = qemu_opt_get(opts, GLUSTER_OPT_PORT);
584             if (!ptr) {
585                 error_setg(&local_err, QERR_MISSING_PARAMETER,
586                            GLUSTER_OPT_PORT);
587                 error_append_hint(&local_err, GERR_INDEX_HINT, i);
588                 goto out;
589             }
590             gsconf->u.inet.port = g_strdup(ptr);
591 
592             /* defend for unsupported fields in InetSocketAddress,
593              * i.e. @ipv4, @ipv6  and @to
594              */
595             ptr = qemu_opt_get(opts, GLUSTER_OPT_TO);
596             if (ptr) {
597                 gsconf->u.inet.has_to = true;
598             }
599             ptr = qemu_opt_get(opts, GLUSTER_OPT_IPV4);
600             if (ptr) {
601                 gsconf->u.inet.has_ipv4 = true;
602             }
603             ptr = qemu_opt_get(opts, GLUSTER_OPT_IPV6);
604             if (ptr) {
605                 gsconf->u.inet.has_ipv6 = true;
606             }
607             if (gsconf->u.inet.has_to) {
608                 error_setg(&local_err, "Parameter 'to' not supported");
609                 goto out;
610             }
611             if (gsconf->u.inet.has_ipv4 || gsconf->u.inet.has_ipv6) {
612                 error_setg(&local_err, "Parameters 'ipv4/ipv6' not supported");
613                 goto out;
614             }
615             qemu_opts_del(opts);
616         } else {
617             /* create opts info from runtime_unix_opts list */
618             opts = qemu_opts_create(&runtime_unix_opts, NULL, 0, &error_abort);
619             qemu_opts_absorb_qdict(opts, backing_options, &local_err);
620             if (local_err) {
621                 goto out;
622             }
623 
624             ptr = qemu_opt_get(opts, GLUSTER_OPT_PATH);
625             if (!ptr) {
626                 ptr = qemu_opt_get(opts, GLUSTER_OPT_SOCKET);
627             } else if (qemu_opt_get(opts, GLUSTER_OPT_SOCKET)) {
628                 error_setg(&local_err,
629                            "Conflicting parameters 'path' and 'socket'");
630                 error_append_hint(&local_err, GERR_INDEX_HINT, i);
631                 goto out;
632             }
633             if (!ptr) {
634                 error_setg(&local_err, QERR_MISSING_PARAMETER,
635                            GLUSTER_OPT_PATH);
636                 error_append_hint(&local_err, GERR_INDEX_HINT, i);
637                 goto out;
638             }
639             gsconf->u.q_unix.path = g_strdup(ptr);
640             qemu_opts_del(opts);
641         }
642 
643         if (gconf->server == NULL) {
644             gconf->server = g_new0(SocketAddressList, 1);
645             gconf->server->value = gsconf;
646             curr = gconf->server;
647         } else {
648             curr->next = g_new0(SocketAddressList, 1);
649             curr->next->value = gsconf;
650             curr = curr->next;
651         }
652         gsconf = NULL;
653 
654         qobject_unref(backing_options);
655         backing_options = NULL;
656         g_free(str);
657         str = NULL;
658     }
659 
660     return 0;
661 
662 out:
663     error_propagate(errp, local_err);
664     qapi_free_SocketAddress(gsconf);
665     qemu_opts_del(opts);
666     g_free(str);
667     qobject_unref(backing_options);
668     errno = EINVAL;
669     return -errno;
670 }
671 
672 /* Converts options given in @filename and the @options QDict into the QAPI
673  * object @gconf. */
674 static int qemu_gluster_parse(BlockdevOptionsGluster *gconf,
675                               const char *filename,
676                               QDict *options, Error **errp)
677 {
678     int ret;
679     if (filename) {
680         ret = qemu_gluster_parse_uri(gconf, filename);
681         if (ret < 0) {
682             error_setg(errp, "invalid URI %s", filename);
683             error_append_hint(errp, "Usage: file=gluster[+transport]://"
684                                     "[host[:port]]volume/path[?socket=...]"
685                                     "[,file.debug=N]"
686                                     "[,file.logfile=/path/filename.log]\n");
687             return ret;
688         }
689     } else {
690         ret = qemu_gluster_parse_json(gconf, options, errp);
691         if (ret < 0) {
692             error_append_hint(errp, "Usage: "
693                              "-drive driver=qcow2,file.driver=gluster,"
694                              "file.volume=testvol,file.path=/path/a.qcow2"
695                              "[,file.debug=9]"
696                              "[,file.logfile=/path/filename.log],"
697                              "file.server.0.type=inet,"
698                              "file.server.0.host=1.2.3.4,"
699                              "file.server.0.port=24007,"
700                              "file.server.1.transport=unix,"
701                              "file.server.1.path=/var/run/glusterd.socket ..."
702                              "\n");
703             return ret;
704         }
705     }
706 
707     return 0;
708 }
709 
710 static struct glfs *qemu_gluster_init(BlockdevOptionsGluster *gconf,
711                                       const char *filename,
712                                       QDict *options, Error **errp)
713 {
714     int ret;
715 
716     ret = qemu_gluster_parse(gconf, filename, options, errp);
717     if (ret < 0) {
718         errno = -ret;
719         return NULL;
720     }
721 
722     return qemu_gluster_glfs_init(gconf, errp);
723 }
724 
725 /*
726  * AIO callback routine called from GlusterFS thread.
727  */
728 static void gluster_finish_aiocb(struct glfs_fd *fd, ssize_t ret, void *arg)
729 {
730     GlusterAIOCB *acb = (GlusterAIOCB *)arg;
731 
732     if (!ret || ret == acb->size) {
733         acb->ret = 0; /* Success */
734     } else if (ret < 0) {
735         acb->ret = -errno; /* Read/Write failed */
736     } else {
737         acb->ret = -EIO; /* Partial read/write - fail it */
738     }
739 
740     aio_co_schedule(acb->aio_context, acb->coroutine);
741 }
742 
743 static void qemu_gluster_parse_flags(int bdrv_flags, int *open_flags)
744 {
745     assert(open_flags != NULL);
746 
747     *open_flags |= O_BINARY;
748 
749     if (bdrv_flags & BDRV_O_RDWR) {
750         *open_flags |= O_RDWR;
751     } else {
752         *open_flags |= O_RDONLY;
753     }
754 
755     if ((bdrv_flags & BDRV_O_NOCACHE)) {
756         *open_flags |= O_DIRECT;
757     }
758 }
759 
760 /*
761  * Do SEEK_DATA/HOLE to detect if it is functional. Older broken versions of
762  * gfapi incorrectly return the current offset when SEEK_DATA/HOLE is used.
763  * - Corrected versions return -1 and set errno to EINVAL.
764  * - Versions that support SEEK_DATA/HOLE correctly, will return -1 and set
765  *   errno to ENXIO when SEEK_DATA is called with a position of EOF.
766  */
767 static bool qemu_gluster_test_seek(struct glfs_fd *fd)
768 {
769     off_t ret = 0;
770 
771 #if defined SEEK_HOLE && defined SEEK_DATA
772     off_t eof;
773 
774     eof = glfs_lseek(fd, 0, SEEK_END);
775     if (eof < 0) {
776         /* this should never occur */
777         return false;
778     }
779 
780     /* this should always fail with ENXIO if SEEK_DATA is supported */
781     ret = glfs_lseek(fd, eof, SEEK_DATA);
782 #endif
783 
784     return (ret < 0) && (errno == ENXIO);
785 }
786 
787 static int qemu_gluster_open(BlockDriverState *bs,  QDict *options,
788                              int bdrv_flags, Error **errp)
789 {
790     BDRVGlusterState *s = bs->opaque;
791     int open_flags = 0;
792     int ret = 0;
793     BlockdevOptionsGluster *gconf = NULL;
794     QemuOpts *opts;
795     Error *local_err = NULL;
796     const char *filename, *logfile;
797 
798     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
799     qemu_opts_absorb_qdict(opts, options, &local_err);
800     if (local_err) {
801         error_propagate(errp, local_err);
802         ret = -EINVAL;
803         goto out;
804     }
805 
806     filename = qemu_opt_get(opts, GLUSTER_OPT_FILENAME);
807 
808     s->debug = qemu_opt_get_number(opts, GLUSTER_OPT_DEBUG,
809                                    GLUSTER_DEBUG_DEFAULT);
810     if (s->debug < 0) {
811         s->debug = 0;
812     } else if (s->debug > GLUSTER_DEBUG_MAX) {
813         s->debug = GLUSTER_DEBUG_MAX;
814     }
815 
816     gconf = g_new0(BlockdevOptionsGluster, 1);
817     gconf->debug = s->debug;
818     gconf->has_debug = true;
819 
820     logfile = qemu_opt_get(opts, GLUSTER_OPT_LOGFILE);
821     s->logfile = g_strdup(logfile ? logfile : GLUSTER_LOGFILE_DEFAULT);
822 
823     gconf->logfile = g_strdup(s->logfile);
824     gconf->has_logfile = true;
825 
826     s->glfs = qemu_gluster_init(gconf, filename, options, errp);
827     if (!s->glfs) {
828         ret = -errno;
829         goto out;
830     }
831 
832 #ifdef CONFIG_GLUSTERFS_XLATOR_OPT
833     /* Without this, if fsync fails for a recoverable reason (for instance,
834      * ENOSPC), gluster will dump its cache, preventing retries.  This means
835      * almost certain data loss.  Not all gluster versions support the
836      * 'resync-failed-syncs-after-fsync' key value, but there is no way to
837      * discover during runtime if it is supported (this api returns success for
838      * unknown key/value pairs) */
839     ret = glfs_set_xlator_option(s->glfs, "*-write-behind",
840                                           "resync-failed-syncs-after-fsync",
841                                           "on");
842     if (ret < 0) {
843         error_setg_errno(errp, errno, "Unable to set xlator key/value pair");
844         ret = -errno;
845         goto out;
846     }
847 #endif
848 
849     qemu_gluster_parse_flags(bdrv_flags, &open_flags);
850 
851     s->fd = glfs_open(s->glfs, gconf->path, open_flags);
852     if (!s->fd) {
853         ret = -errno;
854     }
855 
856     s->supports_seek_data = qemu_gluster_test_seek(s->fd);
857 
858 out:
859     qemu_opts_del(opts);
860     qapi_free_BlockdevOptionsGluster(gconf);
861     if (!ret) {
862         return ret;
863     }
864     g_free(s->logfile);
865     if (s->fd) {
866         glfs_close(s->fd);
867     }
868 
869     glfs_clear_preopened(s->glfs);
870 
871     return ret;
872 }
873 
874 static int qemu_gluster_reopen_prepare(BDRVReopenState *state,
875                                        BlockReopenQueue *queue, Error **errp)
876 {
877     int ret = 0;
878     BDRVGlusterState *s;
879     BDRVGlusterReopenState *reop_s;
880     BlockdevOptionsGluster *gconf;
881     int open_flags = 0;
882 
883     assert(state != NULL);
884     assert(state->bs != NULL);
885 
886     s = state->bs->opaque;
887 
888     state->opaque = g_new0(BDRVGlusterReopenState, 1);
889     reop_s = state->opaque;
890 
891     qemu_gluster_parse_flags(state->flags, &open_flags);
892 
893     gconf = g_new0(BlockdevOptionsGluster, 1);
894     gconf->debug = s->debug;
895     gconf->has_debug = true;
896     gconf->logfile = g_strdup(s->logfile);
897     gconf->has_logfile = true;
898     reop_s->glfs = qemu_gluster_init(gconf, state->bs->filename, NULL, errp);
899     if (reop_s->glfs == NULL) {
900         ret = -errno;
901         goto exit;
902     }
903 
904 #ifdef CONFIG_GLUSTERFS_XLATOR_OPT
905     ret = glfs_set_xlator_option(reop_s->glfs, "*-write-behind",
906                                  "resync-failed-syncs-after-fsync", "on");
907     if (ret < 0) {
908         error_setg_errno(errp, errno, "Unable to set xlator key/value pair");
909         ret = -errno;
910         goto exit;
911     }
912 #endif
913 
914     reop_s->fd = glfs_open(reop_s->glfs, gconf->path, open_flags);
915     if (reop_s->fd == NULL) {
916         /* reops->glfs will be cleaned up in _abort */
917         ret = -errno;
918         goto exit;
919     }
920 
921 exit:
922     /* state->opaque will be freed in either the _abort or _commit */
923     qapi_free_BlockdevOptionsGluster(gconf);
924     return ret;
925 }
926 
927 static void qemu_gluster_reopen_commit(BDRVReopenState *state)
928 {
929     BDRVGlusterReopenState *reop_s = state->opaque;
930     BDRVGlusterState *s = state->bs->opaque;
931 
932 
933     /* close the old */
934     if (s->fd) {
935         glfs_close(s->fd);
936     }
937 
938     glfs_clear_preopened(s->glfs);
939 
940     /* use the newly opened image / connection */
941     s->fd         = reop_s->fd;
942     s->glfs       = reop_s->glfs;
943 
944     g_free(state->opaque);
945     state->opaque = NULL;
946 
947     return;
948 }
949 
950 
951 static void qemu_gluster_reopen_abort(BDRVReopenState *state)
952 {
953     BDRVGlusterReopenState *reop_s = state->opaque;
954 
955     if (reop_s == NULL) {
956         return;
957     }
958 
959     if (reop_s->fd) {
960         glfs_close(reop_s->fd);
961     }
962 
963     glfs_clear_preopened(reop_s->glfs);
964 
965     g_free(state->opaque);
966     state->opaque = NULL;
967 
968     return;
969 }
970 
971 #ifdef CONFIG_GLUSTERFS_ZEROFILL
972 static coroutine_fn int qemu_gluster_co_pwrite_zeroes(BlockDriverState *bs,
973                                                       int64_t offset,
974                                                       int size,
975                                                       BdrvRequestFlags flags)
976 {
977     int ret;
978     GlusterAIOCB acb;
979     BDRVGlusterState *s = bs->opaque;
980 
981     acb.size = size;
982     acb.ret = 0;
983     acb.coroutine = qemu_coroutine_self();
984     acb.aio_context = bdrv_get_aio_context(bs);
985 
986     ret = glfs_zerofill_async(s->fd, offset, size, gluster_finish_aiocb, &acb);
987     if (ret < 0) {
988         return -errno;
989     }
990 
991     qemu_coroutine_yield();
992     return acb.ret;
993 }
994 #endif
995 
996 static int qemu_gluster_do_truncate(struct glfs_fd *fd, int64_t offset,
997                                     PreallocMode prealloc, Error **errp)
998 {
999     int64_t current_length;
1000 
1001     current_length = glfs_lseek(fd, 0, SEEK_END);
1002     if (current_length < 0) {
1003         error_setg_errno(errp, errno, "Failed to determine current size");
1004         return -errno;
1005     }
1006 
1007     if (current_length > offset && prealloc != PREALLOC_MODE_OFF) {
1008         error_setg(errp, "Cannot use preallocation for shrinking files");
1009         return -ENOTSUP;
1010     }
1011 
1012     if (current_length == offset) {
1013         return 0;
1014     }
1015 
1016     switch (prealloc) {
1017 #ifdef CONFIG_GLUSTERFS_FALLOCATE
1018     case PREALLOC_MODE_FALLOC:
1019         if (glfs_fallocate(fd, 0, current_length, offset - current_length)) {
1020             error_setg_errno(errp, errno, "Could not preallocate data");
1021             return -errno;
1022         }
1023         break;
1024 #endif /* CONFIG_GLUSTERFS_FALLOCATE */
1025 #ifdef CONFIG_GLUSTERFS_ZEROFILL
1026     case PREALLOC_MODE_FULL:
1027         if (glfs_ftruncate(fd, offset)) {
1028             error_setg_errno(errp, errno, "Could not resize file");
1029             return -errno;
1030         }
1031         if (glfs_zerofill(fd, current_length, offset - current_length)) {
1032             error_setg_errno(errp, errno, "Could not zerofill the new area");
1033             return -errno;
1034         }
1035         break;
1036 #endif /* CONFIG_GLUSTERFS_ZEROFILL */
1037     case PREALLOC_MODE_OFF:
1038         if (glfs_ftruncate(fd, offset)) {
1039             error_setg_errno(errp, errno, "Could not resize file");
1040             return -errno;
1041         }
1042         break;
1043     default:
1044         error_setg(errp, "Unsupported preallocation mode: %s",
1045                    PreallocMode_str(prealloc));
1046         return -EINVAL;
1047     }
1048 
1049     return 0;
1050 }
1051 
1052 static int qemu_gluster_co_create(BlockdevCreateOptions *options,
1053                                   Error **errp)
1054 {
1055     BlockdevCreateOptionsGluster *opts = &options->u.gluster;
1056     struct glfs *glfs;
1057     struct glfs_fd *fd = NULL;
1058     int ret = 0;
1059 
1060     assert(options->driver == BLOCKDEV_DRIVER_GLUSTER);
1061 
1062     glfs = qemu_gluster_glfs_init(opts->location, errp);
1063     if (!glfs) {
1064         ret = -errno;
1065         goto out;
1066     }
1067 
1068     fd = glfs_creat(glfs, opts->location->path,
1069                     O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, S_IRUSR | S_IWUSR);
1070     if (!fd) {
1071         ret = -errno;
1072         goto out;
1073     }
1074 
1075     ret = qemu_gluster_do_truncate(fd, opts->size, opts->preallocation, errp);
1076 
1077 out:
1078     if (fd) {
1079         if (glfs_close(fd) != 0 && ret == 0) {
1080             ret = -errno;
1081         }
1082     }
1083     glfs_clear_preopened(glfs);
1084     return ret;
1085 }
1086 
1087 static int coroutine_fn qemu_gluster_co_create_opts(const char *filename,
1088                                                     QemuOpts *opts,
1089                                                     Error **errp)
1090 {
1091     BlockdevCreateOptions *options;
1092     BlockdevCreateOptionsGluster *gopts;
1093     BlockdevOptionsGluster *gconf;
1094     char *tmp = NULL;
1095     Error *local_err = NULL;
1096     int ret;
1097 
1098     options = g_new0(BlockdevCreateOptions, 1);
1099     options->driver = BLOCKDEV_DRIVER_GLUSTER;
1100     gopts = &options->u.gluster;
1101 
1102     gconf = g_new0(BlockdevOptionsGluster, 1);
1103     gopts->location = gconf;
1104 
1105     gopts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
1106                            BDRV_SECTOR_SIZE);
1107 
1108     tmp = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
1109     gopts->preallocation = qapi_enum_parse(&PreallocMode_lookup, tmp,
1110                                            PREALLOC_MODE_OFF, &local_err);
1111     g_free(tmp);
1112     if (local_err) {
1113         error_propagate(errp, local_err);
1114         ret = -EINVAL;
1115         goto fail;
1116     }
1117 
1118     gconf->debug = qemu_opt_get_number_del(opts, GLUSTER_OPT_DEBUG,
1119                                            GLUSTER_DEBUG_DEFAULT);
1120     if (gconf->debug < 0) {
1121         gconf->debug = 0;
1122     } else if (gconf->debug > GLUSTER_DEBUG_MAX) {
1123         gconf->debug = GLUSTER_DEBUG_MAX;
1124     }
1125     gconf->has_debug = true;
1126 
1127     gconf->logfile = qemu_opt_get_del(opts, GLUSTER_OPT_LOGFILE);
1128     if (!gconf->logfile) {
1129         gconf->logfile = g_strdup(GLUSTER_LOGFILE_DEFAULT);
1130     }
1131     gconf->has_logfile = true;
1132 
1133     ret = qemu_gluster_parse(gconf, filename, NULL, errp);
1134     if (ret < 0) {
1135         goto fail;
1136     }
1137 
1138     ret = qemu_gluster_co_create(options, errp);
1139     if (ret < 0) {
1140         goto fail;
1141     }
1142 
1143     ret = 0;
1144 fail:
1145     qapi_free_BlockdevCreateOptions(options);
1146     return ret;
1147 }
1148 
1149 static coroutine_fn int qemu_gluster_co_rw(BlockDriverState *bs,
1150                                            int64_t sector_num, int nb_sectors,
1151                                            QEMUIOVector *qiov, int write)
1152 {
1153     int ret;
1154     GlusterAIOCB acb;
1155     BDRVGlusterState *s = bs->opaque;
1156     size_t size = nb_sectors * BDRV_SECTOR_SIZE;
1157     off_t offset = sector_num * BDRV_SECTOR_SIZE;
1158 
1159     acb.size = size;
1160     acb.ret = 0;
1161     acb.coroutine = qemu_coroutine_self();
1162     acb.aio_context = bdrv_get_aio_context(bs);
1163 
1164     if (write) {
1165         ret = glfs_pwritev_async(s->fd, qiov->iov, qiov->niov, offset, 0,
1166                                  gluster_finish_aiocb, &acb);
1167     } else {
1168         ret = glfs_preadv_async(s->fd, qiov->iov, qiov->niov, offset, 0,
1169                                 gluster_finish_aiocb, &acb);
1170     }
1171 
1172     if (ret < 0) {
1173         return -errno;
1174     }
1175 
1176     qemu_coroutine_yield();
1177     return acb.ret;
1178 }
1179 
1180 static coroutine_fn int qemu_gluster_co_truncate(BlockDriverState *bs,
1181                                                  int64_t offset,
1182                                                  PreallocMode prealloc,
1183                                                  Error **errp)
1184 {
1185     BDRVGlusterState *s = bs->opaque;
1186     return qemu_gluster_do_truncate(s->fd, offset, prealloc, errp);
1187 }
1188 
1189 static coroutine_fn int qemu_gluster_co_readv(BlockDriverState *bs,
1190                                               int64_t sector_num,
1191                                               int nb_sectors,
1192                                               QEMUIOVector *qiov)
1193 {
1194     return qemu_gluster_co_rw(bs, sector_num, nb_sectors, qiov, 0);
1195 }
1196 
1197 static coroutine_fn int qemu_gluster_co_writev(BlockDriverState *bs,
1198                                                int64_t sector_num,
1199                                                int nb_sectors,
1200                                                QEMUIOVector *qiov,
1201                                                int flags)
1202 {
1203     assert(!flags);
1204     return qemu_gluster_co_rw(bs, sector_num, nb_sectors, qiov, 1);
1205 }
1206 
1207 static void qemu_gluster_close(BlockDriverState *bs)
1208 {
1209     BDRVGlusterState *s = bs->opaque;
1210 
1211     g_free(s->logfile);
1212     if (s->fd) {
1213         glfs_close(s->fd);
1214         s->fd = NULL;
1215     }
1216     glfs_clear_preopened(s->glfs);
1217 }
1218 
1219 static coroutine_fn int qemu_gluster_co_flush_to_disk(BlockDriverState *bs)
1220 {
1221     int ret;
1222     GlusterAIOCB acb;
1223     BDRVGlusterState *s = bs->opaque;
1224 
1225     acb.size = 0;
1226     acb.ret = 0;
1227     acb.coroutine = qemu_coroutine_self();
1228     acb.aio_context = bdrv_get_aio_context(bs);
1229 
1230     ret = glfs_fsync_async(s->fd, gluster_finish_aiocb, &acb);
1231     if (ret < 0) {
1232         ret = -errno;
1233         goto error;
1234     }
1235 
1236     qemu_coroutine_yield();
1237     if (acb.ret < 0) {
1238         ret = acb.ret;
1239         goto error;
1240     }
1241 
1242     return acb.ret;
1243 
1244 error:
1245     /* Some versions of Gluster (3.5.6 -> 3.5.8?) will not retain its cache
1246      * after a fsync failure, so we have no way of allowing the guest to safely
1247      * continue.  Gluster versions prior to 3.5.6 don't retain the cache
1248      * either, but will invalidate the fd on error, so this is again our only
1249      * option.
1250      *
1251      * The 'resync-failed-syncs-after-fsync' xlator option for the
1252      * write-behind cache will cause later gluster versions to retain its
1253      * cache after error, so long as the fd remains open.  However, we
1254      * currently have no way of knowing if this option is supported.
1255      *
1256      * TODO: Once gluster provides a way for us to determine if the option
1257      * is supported, bypass the closure and setting drv to NULL.  */
1258     qemu_gluster_close(bs);
1259     bs->drv = NULL;
1260     return ret;
1261 }
1262 
1263 #ifdef CONFIG_GLUSTERFS_DISCARD
1264 static coroutine_fn int qemu_gluster_co_pdiscard(BlockDriverState *bs,
1265                                                  int64_t offset, int size)
1266 {
1267     int ret;
1268     GlusterAIOCB acb;
1269     BDRVGlusterState *s = bs->opaque;
1270 
1271     acb.size = 0;
1272     acb.ret = 0;
1273     acb.coroutine = qemu_coroutine_self();
1274     acb.aio_context = bdrv_get_aio_context(bs);
1275 
1276     ret = glfs_discard_async(s->fd, offset, size, gluster_finish_aiocb, &acb);
1277     if (ret < 0) {
1278         return -errno;
1279     }
1280 
1281     qemu_coroutine_yield();
1282     return acb.ret;
1283 }
1284 #endif
1285 
1286 static int64_t qemu_gluster_getlength(BlockDriverState *bs)
1287 {
1288     BDRVGlusterState *s = bs->opaque;
1289     int64_t ret;
1290 
1291     ret = glfs_lseek(s->fd, 0, SEEK_END);
1292     if (ret < 0) {
1293         return -errno;
1294     } else {
1295         return ret;
1296     }
1297 }
1298 
1299 static int64_t qemu_gluster_allocated_file_size(BlockDriverState *bs)
1300 {
1301     BDRVGlusterState *s = bs->opaque;
1302     struct stat st;
1303     int ret;
1304 
1305     ret = glfs_fstat(s->fd, &st);
1306     if (ret < 0) {
1307         return -errno;
1308     } else {
1309         return st.st_blocks * 512;
1310     }
1311 }
1312 
1313 static int qemu_gluster_has_zero_init(BlockDriverState *bs)
1314 {
1315     /* GlusterFS volume could be backed by a block device */
1316     return 0;
1317 }
1318 
1319 /*
1320  * Find allocation range in @bs around offset @start.
1321  * May change underlying file descriptor's file offset.
1322  * If @start is not in a hole, store @start in @data, and the
1323  * beginning of the next hole in @hole, and return 0.
1324  * If @start is in a non-trailing hole, store @start in @hole and the
1325  * beginning of the next non-hole in @data, and return 0.
1326  * If @start is in a trailing hole or beyond EOF, return -ENXIO.
1327  * If we can't find out, return a negative errno other than -ENXIO.
1328  *
1329  * (Shamefully copied from file-posix.c, only minuscule adaptions.)
1330  */
1331 static int find_allocation(BlockDriverState *bs, off_t start,
1332                            off_t *data, off_t *hole)
1333 {
1334     BDRVGlusterState *s = bs->opaque;
1335 
1336     if (!s->supports_seek_data) {
1337         goto exit;
1338     }
1339 
1340 #if defined SEEK_HOLE && defined SEEK_DATA
1341     off_t offs;
1342 
1343     /*
1344      * SEEK_DATA cases:
1345      * D1. offs == start: start is in data
1346      * D2. offs > start: start is in a hole, next data at offs
1347      * D3. offs < 0, errno = ENXIO: either start is in a trailing hole
1348      *                              or start is beyond EOF
1349      *     If the latter happens, the file has been truncated behind
1350      *     our back since we opened it.  All bets are off then.
1351      *     Treating like a trailing hole is simplest.
1352      * D4. offs < 0, errno != ENXIO: we learned nothing
1353      */
1354     offs = glfs_lseek(s->fd, start, SEEK_DATA);
1355     if (offs < 0) {
1356         return -errno;          /* D3 or D4 */
1357     }
1358 
1359     if (offs < start) {
1360         /* This is not a valid return by lseek().  We are safe to just return
1361          * -EIO in this case, and we'll treat it like D4. Unfortunately some
1362          *  versions of gluster server will return offs < start, so an assert
1363          *  here will unnecessarily abort QEMU. */
1364         return -EIO;
1365     }
1366 
1367     if (offs > start) {
1368         /* D2: in hole, next data at offs */
1369         *hole = start;
1370         *data = offs;
1371         return 0;
1372     }
1373 
1374     /* D1: in data, end not yet known */
1375 
1376     /*
1377      * SEEK_HOLE cases:
1378      * H1. offs == start: start is in a hole
1379      *     If this happens here, a hole has been dug behind our back
1380      *     since the previous lseek().
1381      * H2. offs > start: either start is in data, next hole at offs,
1382      *                   or start is in trailing hole, EOF at offs
1383      *     Linux treats trailing holes like any other hole: offs ==
1384      *     start.  Solaris seeks to EOF instead: offs > start (blech).
1385      *     If that happens here, a hole has been dug behind our back
1386      *     since the previous lseek().
1387      * H3. offs < 0, errno = ENXIO: start is beyond EOF
1388      *     If this happens, the file has been truncated behind our
1389      *     back since we opened it.  Treat it like a trailing hole.
1390      * H4. offs < 0, errno != ENXIO: we learned nothing
1391      *     Pretend we know nothing at all, i.e. "forget" about D1.
1392      */
1393     offs = glfs_lseek(s->fd, start, SEEK_HOLE);
1394     if (offs < 0) {
1395         return -errno;          /* D1 and (H3 or H4) */
1396     }
1397 
1398     if (offs < start) {
1399         /* This is not a valid return by lseek().  We are safe to just return
1400          * -EIO in this case, and we'll treat it like H4. Unfortunately some
1401          *  versions of gluster server will return offs < start, so an assert
1402          *  here will unnecessarily abort QEMU. */
1403         return -EIO;
1404     }
1405 
1406     if (offs > start) {
1407         /*
1408          * D1 and H2: either in data, next hole at offs, or it was in
1409          * data but is now in a trailing hole.  In the latter case,
1410          * all bets are off.  Treating it as if it there was data all
1411          * the way to EOF is safe, so simply do that.
1412          */
1413         *data = start;
1414         *hole = offs;
1415         return 0;
1416     }
1417 
1418     /* D1 and H1 */
1419     return -EBUSY;
1420 #endif
1421 
1422 exit:
1423     return -ENOTSUP;
1424 }
1425 
1426 /*
1427  * Returns the allocation status of the specified offset.
1428  *
1429  * The block layer guarantees 'offset' and 'bytes' are within bounds.
1430  *
1431  * 'pnum' is set to the number of bytes (including and immediately following
1432  * the specified offset) that are known to be in the same
1433  * allocated/unallocated state.
1434  *
1435  * 'bytes' is the max value 'pnum' should be set to.
1436  *
1437  * (Based on raw_co_block_status() from file-posix.c.)
1438  */
1439 static int coroutine_fn qemu_gluster_co_block_status(BlockDriverState *bs,
1440                                                      bool want_zero,
1441                                                      int64_t offset,
1442                                                      int64_t bytes,
1443                                                      int64_t *pnum,
1444                                                      int64_t *map,
1445                                                      BlockDriverState **file)
1446 {
1447     BDRVGlusterState *s = bs->opaque;
1448     off_t data = 0, hole = 0;
1449     int ret = -EINVAL;
1450 
1451     if (!s->fd) {
1452         return ret;
1453     }
1454 
1455     if (!want_zero) {
1456         *pnum = bytes;
1457         *map = offset;
1458         *file = bs;
1459         return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
1460     }
1461 
1462     ret = find_allocation(bs, offset, &data, &hole);
1463     if (ret == -ENXIO) {
1464         /* Trailing hole */
1465         *pnum = bytes;
1466         ret = BDRV_BLOCK_ZERO;
1467     } else if (ret < 0) {
1468         /* No info available, so pretend there are no holes */
1469         *pnum = bytes;
1470         ret = BDRV_BLOCK_DATA;
1471     } else if (data == offset) {
1472         /* On a data extent, compute bytes to the end of the extent,
1473          * possibly including a partial sector at EOF. */
1474         *pnum = MIN(bytes, hole - offset);
1475         ret = BDRV_BLOCK_DATA;
1476     } else {
1477         /* On a hole, compute bytes to the beginning of the next extent.  */
1478         assert(hole == offset);
1479         *pnum = MIN(bytes, data - offset);
1480         ret = BDRV_BLOCK_ZERO;
1481     }
1482 
1483     *map = offset;
1484     *file = bs;
1485 
1486     return ret | BDRV_BLOCK_OFFSET_VALID;
1487 }
1488 
1489 
1490 static BlockDriver bdrv_gluster = {
1491     .format_name                  = "gluster",
1492     .protocol_name                = "gluster",
1493     .instance_size                = sizeof(BDRVGlusterState),
1494     .bdrv_needs_filename          = false,
1495     .bdrv_file_open               = qemu_gluster_open,
1496     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
1497     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
1498     .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
1499     .bdrv_close                   = qemu_gluster_close,
1500     .bdrv_co_create               = qemu_gluster_co_create,
1501     .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
1502     .bdrv_getlength               = qemu_gluster_getlength,
1503     .bdrv_get_allocated_file_size = qemu_gluster_allocated_file_size,
1504     .bdrv_co_truncate             = qemu_gluster_co_truncate,
1505     .bdrv_co_readv                = qemu_gluster_co_readv,
1506     .bdrv_co_writev               = qemu_gluster_co_writev,
1507     .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
1508     .bdrv_has_zero_init           = qemu_gluster_has_zero_init,
1509 #ifdef CONFIG_GLUSTERFS_DISCARD
1510     .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
1511 #endif
1512 #ifdef CONFIG_GLUSTERFS_ZEROFILL
1513     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
1514 #endif
1515     .bdrv_co_block_status         = qemu_gluster_co_block_status,
1516     .create_opts                  = &qemu_gluster_create_opts,
1517 };
1518 
1519 static BlockDriver bdrv_gluster_tcp = {
1520     .format_name                  = "gluster",
1521     .protocol_name                = "gluster+tcp",
1522     .instance_size                = sizeof(BDRVGlusterState),
1523     .bdrv_needs_filename          = false,
1524     .bdrv_file_open               = qemu_gluster_open,
1525     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
1526     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
1527     .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
1528     .bdrv_close                   = qemu_gluster_close,
1529     .bdrv_co_create               = qemu_gluster_co_create,
1530     .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
1531     .bdrv_getlength               = qemu_gluster_getlength,
1532     .bdrv_get_allocated_file_size = qemu_gluster_allocated_file_size,
1533     .bdrv_co_truncate             = qemu_gluster_co_truncate,
1534     .bdrv_co_readv                = qemu_gluster_co_readv,
1535     .bdrv_co_writev               = qemu_gluster_co_writev,
1536     .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
1537     .bdrv_has_zero_init           = qemu_gluster_has_zero_init,
1538 #ifdef CONFIG_GLUSTERFS_DISCARD
1539     .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
1540 #endif
1541 #ifdef CONFIG_GLUSTERFS_ZEROFILL
1542     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
1543 #endif
1544     .bdrv_co_block_status         = qemu_gluster_co_block_status,
1545     .create_opts                  = &qemu_gluster_create_opts,
1546 };
1547 
1548 static BlockDriver bdrv_gluster_unix = {
1549     .format_name                  = "gluster",
1550     .protocol_name                = "gluster+unix",
1551     .instance_size                = sizeof(BDRVGlusterState),
1552     .bdrv_needs_filename          = true,
1553     .bdrv_file_open               = qemu_gluster_open,
1554     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
1555     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
1556     .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
1557     .bdrv_close                   = qemu_gluster_close,
1558     .bdrv_co_create               = qemu_gluster_co_create,
1559     .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
1560     .bdrv_getlength               = qemu_gluster_getlength,
1561     .bdrv_get_allocated_file_size = qemu_gluster_allocated_file_size,
1562     .bdrv_co_truncate             = qemu_gluster_co_truncate,
1563     .bdrv_co_readv                = qemu_gluster_co_readv,
1564     .bdrv_co_writev               = qemu_gluster_co_writev,
1565     .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
1566     .bdrv_has_zero_init           = qemu_gluster_has_zero_init,
1567 #ifdef CONFIG_GLUSTERFS_DISCARD
1568     .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
1569 #endif
1570 #ifdef CONFIG_GLUSTERFS_ZEROFILL
1571     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
1572 #endif
1573     .bdrv_co_block_status         = qemu_gluster_co_block_status,
1574     .create_opts                  = &qemu_gluster_create_opts,
1575 };
1576 
1577 /* rdma is deprecated (actually never supported for volfile fetch).
1578  * Let's maintain it for the protocol compatibility, to make sure things
1579  * won't break immediately. For now, gluster+rdma will fall back to gluster+tcp
1580  * protocol with a warning.
1581  * TODO: remove gluster+rdma interface support
1582  */
1583 static BlockDriver bdrv_gluster_rdma = {
1584     .format_name                  = "gluster",
1585     .protocol_name                = "gluster+rdma",
1586     .instance_size                = sizeof(BDRVGlusterState),
1587     .bdrv_needs_filename          = true,
1588     .bdrv_file_open               = qemu_gluster_open,
1589     .bdrv_reopen_prepare          = qemu_gluster_reopen_prepare,
1590     .bdrv_reopen_commit           = qemu_gluster_reopen_commit,
1591     .bdrv_reopen_abort            = qemu_gluster_reopen_abort,
1592     .bdrv_close                   = qemu_gluster_close,
1593     .bdrv_co_create               = qemu_gluster_co_create,
1594     .bdrv_co_create_opts          = qemu_gluster_co_create_opts,
1595     .bdrv_getlength               = qemu_gluster_getlength,
1596     .bdrv_get_allocated_file_size = qemu_gluster_allocated_file_size,
1597     .bdrv_co_truncate             = qemu_gluster_co_truncate,
1598     .bdrv_co_readv                = qemu_gluster_co_readv,
1599     .bdrv_co_writev               = qemu_gluster_co_writev,
1600     .bdrv_co_flush_to_disk        = qemu_gluster_co_flush_to_disk,
1601     .bdrv_has_zero_init           = qemu_gluster_has_zero_init,
1602 #ifdef CONFIG_GLUSTERFS_DISCARD
1603     .bdrv_co_pdiscard             = qemu_gluster_co_pdiscard,
1604 #endif
1605 #ifdef CONFIG_GLUSTERFS_ZEROFILL
1606     .bdrv_co_pwrite_zeroes        = qemu_gluster_co_pwrite_zeroes,
1607 #endif
1608     .bdrv_co_block_status         = qemu_gluster_co_block_status,
1609     .create_opts                  = &qemu_gluster_create_opts,
1610 };
1611 
1612 static void bdrv_gluster_init(void)
1613 {
1614     bdrv_register(&bdrv_gluster_rdma);
1615     bdrv_register(&bdrv_gluster_unix);
1616     bdrv_register(&bdrv_gluster_tcp);
1617     bdrv_register(&bdrv_gluster);
1618 }
1619 
1620 block_init(bdrv_gluster_init);
1621