xref: /qemu/block/blkdebug.c (revision f505a4d74aae6fc8bb5502a6038b5f671aa97713)
1 /*
2  * Block protocol for I/O error injection
3  *
4  * Copyright (c) 2010 Kevin Wolf <kwolf@redhat.com>
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 
25 #include "qemu-common.h"
26 #include "qemu/config-file.h"
27 #include "block/block_int.h"
28 #include "qemu/module.h"
29 
30 typedef struct BDRVBlkdebugState {
31     int state;
32     int new_state;
33 
34     QLIST_HEAD(, BlkdebugRule) rules[BLKDBG_EVENT_MAX];
35     QSIMPLEQ_HEAD(, BlkdebugRule) active_rules;
36     QLIST_HEAD(, BlkdebugSuspendedReq) suspended_reqs;
37 } BDRVBlkdebugState;
38 
39 typedef struct BlkdebugAIOCB {
40     BlockDriverAIOCB common;
41     QEMUBH *bh;
42     int ret;
43 } BlkdebugAIOCB;
44 
45 typedef struct BlkdebugSuspendedReq {
46     Coroutine *co;
47     char *tag;
48     QLIST_ENTRY(BlkdebugSuspendedReq) next;
49 } BlkdebugSuspendedReq;
50 
51 static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb);
52 
53 static const AIOCBInfo blkdebug_aiocb_info = {
54     .aiocb_size = sizeof(BlkdebugAIOCB),
55     .cancel     = blkdebug_aio_cancel,
56 };
57 
58 enum {
59     ACTION_INJECT_ERROR,
60     ACTION_SET_STATE,
61     ACTION_SUSPEND,
62 };
63 
64 typedef struct BlkdebugRule {
65     BlkDebugEvent event;
66     int action;
67     int state;
68     union {
69         struct {
70             int error;
71             int immediately;
72             int once;
73             int64_t sector;
74         } inject;
75         struct {
76             int new_state;
77         } set_state;
78         struct {
79             char *tag;
80         } suspend;
81     } options;
82     QLIST_ENTRY(BlkdebugRule) next;
83     QSIMPLEQ_ENTRY(BlkdebugRule) active_next;
84 } BlkdebugRule;
85 
86 static QemuOptsList inject_error_opts = {
87     .name = "inject-error",
88     .head = QTAILQ_HEAD_INITIALIZER(inject_error_opts.head),
89     .desc = {
90         {
91             .name = "event",
92             .type = QEMU_OPT_STRING,
93         },
94         {
95             .name = "state",
96             .type = QEMU_OPT_NUMBER,
97         },
98         {
99             .name = "errno",
100             .type = QEMU_OPT_NUMBER,
101         },
102         {
103             .name = "sector",
104             .type = QEMU_OPT_NUMBER,
105         },
106         {
107             .name = "once",
108             .type = QEMU_OPT_BOOL,
109         },
110         {
111             .name = "immediately",
112             .type = QEMU_OPT_BOOL,
113         },
114         { /* end of list */ }
115     },
116 };
117 
118 static QemuOptsList set_state_opts = {
119     .name = "set-state",
120     .head = QTAILQ_HEAD_INITIALIZER(set_state_opts.head),
121     .desc = {
122         {
123             .name = "event",
124             .type = QEMU_OPT_STRING,
125         },
126         {
127             .name = "state",
128             .type = QEMU_OPT_NUMBER,
129         },
130         {
131             .name = "new_state",
132             .type = QEMU_OPT_NUMBER,
133         },
134         { /* end of list */ }
135     },
136 };
137 
138 static QemuOptsList *config_groups[] = {
139     &inject_error_opts,
140     &set_state_opts,
141     NULL
142 };
143 
144 static const char *event_names[BLKDBG_EVENT_MAX] = {
145     [BLKDBG_L1_UPDATE]                      = "l1_update",
146     [BLKDBG_L1_GROW_ALLOC_TABLE]            = "l1_grow.alloc_table",
147     [BLKDBG_L1_GROW_WRITE_TABLE]            = "l1_grow.write_table",
148     [BLKDBG_L1_GROW_ACTIVATE_TABLE]         = "l1_grow.activate_table",
149 
150     [BLKDBG_L2_LOAD]                        = "l2_load",
151     [BLKDBG_L2_UPDATE]                      = "l2_update",
152     [BLKDBG_L2_UPDATE_COMPRESSED]           = "l2_update_compressed",
153     [BLKDBG_L2_ALLOC_COW_READ]              = "l2_alloc.cow_read",
154     [BLKDBG_L2_ALLOC_WRITE]                 = "l2_alloc.write",
155 
156     [BLKDBG_READ_AIO]                       = "read_aio",
157     [BLKDBG_READ_BACKING_AIO]               = "read_backing_aio",
158     [BLKDBG_READ_COMPRESSED]                = "read_compressed",
159 
160     [BLKDBG_WRITE_AIO]                      = "write_aio",
161     [BLKDBG_WRITE_COMPRESSED]               = "write_compressed",
162 
163     [BLKDBG_VMSTATE_LOAD]                   = "vmstate_load",
164     [BLKDBG_VMSTATE_SAVE]                   = "vmstate_save",
165 
166     [BLKDBG_COW_READ]                       = "cow_read",
167     [BLKDBG_COW_WRITE]                      = "cow_write",
168 
169     [BLKDBG_REFTABLE_LOAD]                  = "reftable_load",
170     [BLKDBG_REFTABLE_GROW]                  = "reftable_grow",
171 
172     [BLKDBG_REFBLOCK_LOAD]                  = "refblock_load",
173     [BLKDBG_REFBLOCK_UPDATE]                = "refblock_update",
174     [BLKDBG_REFBLOCK_UPDATE_PART]           = "refblock_update_part",
175     [BLKDBG_REFBLOCK_ALLOC]                 = "refblock_alloc",
176     [BLKDBG_REFBLOCK_ALLOC_HOOKUP]          = "refblock_alloc.hookup",
177     [BLKDBG_REFBLOCK_ALLOC_WRITE]           = "refblock_alloc.write",
178     [BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS]    = "refblock_alloc.write_blocks",
179     [BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE]     = "refblock_alloc.write_table",
180     [BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE]    = "refblock_alloc.switch_table",
181 
182     [BLKDBG_CLUSTER_ALLOC]                  = "cluster_alloc",
183     [BLKDBG_CLUSTER_ALLOC_BYTES]            = "cluster_alloc_bytes",
184     [BLKDBG_CLUSTER_FREE]                   = "cluster_free",
185 };
186 
187 static int get_event_by_name(const char *name, BlkDebugEvent *event)
188 {
189     int i;
190 
191     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
192         if (!strcmp(event_names[i], name)) {
193             *event = i;
194             return 0;
195         }
196     }
197 
198     return -1;
199 }
200 
201 struct add_rule_data {
202     BDRVBlkdebugState *s;
203     int action;
204 };
205 
206 static int add_rule(QemuOpts *opts, void *opaque)
207 {
208     struct add_rule_data *d = opaque;
209     BDRVBlkdebugState *s = d->s;
210     const char* event_name;
211     BlkDebugEvent event;
212     struct BlkdebugRule *rule;
213 
214     /* Find the right event for the rule */
215     event_name = qemu_opt_get(opts, "event");
216     if (!event_name || get_event_by_name(event_name, &event) < 0) {
217         return -1;
218     }
219 
220     /* Set attributes common for all actions */
221     rule = g_malloc0(sizeof(*rule));
222     *rule = (struct BlkdebugRule) {
223         .event  = event,
224         .action = d->action,
225         .state  = qemu_opt_get_number(opts, "state", 0),
226     };
227 
228     /* Parse action-specific options */
229     switch (d->action) {
230     case ACTION_INJECT_ERROR:
231         rule->options.inject.error = qemu_opt_get_number(opts, "errno", EIO);
232         rule->options.inject.once  = qemu_opt_get_bool(opts, "once", 0);
233         rule->options.inject.immediately =
234             qemu_opt_get_bool(opts, "immediately", 0);
235         rule->options.inject.sector = qemu_opt_get_number(opts, "sector", -1);
236         break;
237 
238     case ACTION_SET_STATE:
239         rule->options.set_state.new_state =
240             qemu_opt_get_number(opts, "new_state", 0);
241         break;
242 
243     case ACTION_SUSPEND:
244         rule->options.suspend.tag =
245             g_strdup(qemu_opt_get(opts, "tag"));
246         break;
247     };
248 
249     /* Add the rule */
250     QLIST_INSERT_HEAD(&s->rules[event], rule, next);
251 
252     return 0;
253 }
254 
255 static void remove_rule(BlkdebugRule *rule)
256 {
257     switch (rule->action) {
258     case ACTION_INJECT_ERROR:
259     case ACTION_SET_STATE:
260         break;
261     case ACTION_SUSPEND:
262         g_free(rule->options.suspend.tag);
263         break;
264     }
265 
266     QLIST_REMOVE(rule, next);
267     g_free(rule);
268 }
269 
270 static int read_config(BDRVBlkdebugState *s, const char *filename)
271 {
272     FILE *f;
273     int ret;
274     struct add_rule_data d;
275 
276     /* Allow usage without config file */
277     if (!*filename) {
278         return 0;
279     }
280 
281     f = fopen(filename, "r");
282     if (f == NULL) {
283         return -errno;
284     }
285 
286     ret = qemu_config_parse(f, config_groups, filename);
287     if (ret < 0) {
288         goto fail;
289     }
290 
291     d.s = s;
292     d.action = ACTION_INJECT_ERROR;
293     qemu_opts_foreach(&inject_error_opts, add_rule, &d, 0);
294 
295     d.action = ACTION_SET_STATE;
296     qemu_opts_foreach(&set_state_opts, add_rule, &d, 0);
297 
298     ret = 0;
299 fail:
300     qemu_opts_reset(&inject_error_opts);
301     qemu_opts_reset(&set_state_opts);
302     fclose(f);
303     return ret;
304 }
305 
306 /* Valid blkdebug filenames look like blkdebug:path/to/config:path/to/image */
307 static int blkdebug_open(BlockDriverState *bs, const char *filename,
308                          QDict *options, int flags)
309 {
310     BDRVBlkdebugState *s = bs->opaque;
311     int ret;
312     char *config, *c;
313 
314     /* Parse the blkdebug: prefix */
315     if (strncmp(filename, "blkdebug:", strlen("blkdebug:"))) {
316         return -EINVAL;
317     }
318     filename += strlen("blkdebug:");
319 
320     /* Read rules from config file */
321     c = strchr(filename, ':');
322     if (c == NULL) {
323         return -EINVAL;
324     }
325 
326     config = g_strdup(filename);
327     config[c - filename] = '\0';
328     ret = read_config(s, config);
329     g_free(config);
330     if (ret < 0) {
331         return ret;
332     }
333     filename = c + 1;
334 
335     /* Set initial state */
336     s->state = 1;
337 
338     /* Open the backing file */
339     ret = bdrv_file_open(&bs->file, filename, NULL, flags);
340     if (ret < 0) {
341         return ret;
342     }
343 
344     return 0;
345 }
346 
347 static void error_callback_bh(void *opaque)
348 {
349     struct BlkdebugAIOCB *acb = opaque;
350     qemu_bh_delete(acb->bh);
351     acb->common.cb(acb->common.opaque, acb->ret);
352     qemu_aio_release(acb);
353 }
354 
355 static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb)
356 {
357     BlkdebugAIOCB *acb = container_of(blockacb, BlkdebugAIOCB, common);
358     qemu_aio_release(acb);
359 }
360 
361 static BlockDriverAIOCB *inject_error(BlockDriverState *bs,
362     BlockDriverCompletionFunc *cb, void *opaque, BlkdebugRule *rule)
363 {
364     BDRVBlkdebugState *s = bs->opaque;
365     int error = rule->options.inject.error;
366     struct BlkdebugAIOCB *acb;
367     QEMUBH *bh;
368 
369     if (rule->options.inject.once) {
370         QSIMPLEQ_INIT(&s->active_rules);
371     }
372 
373     if (rule->options.inject.immediately) {
374         return NULL;
375     }
376 
377     acb = qemu_aio_get(&blkdebug_aiocb_info, bs, cb, opaque);
378     acb->ret = -error;
379 
380     bh = qemu_bh_new(error_callback_bh, acb);
381     acb->bh = bh;
382     qemu_bh_schedule(bh);
383 
384     return &acb->common;
385 }
386 
387 static BlockDriverAIOCB *blkdebug_aio_readv(BlockDriverState *bs,
388     int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
389     BlockDriverCompletionFunc *cb, void *opaque)
390 {
391     BDRVBlkdebugState *s = bs->opaque;
392     BlkdebugRule *rule = NULL;
393 
394     QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
395         if (rule->options.inject.sector == -1 ||
396             (rule->options.inject.sector >= sector_num &&
397              rule->options.inject.sector < sector_num + nb_sectors)) {
398             break;
399         }
400     }
401 
402     if (rule && rule->options.inject.error) {
403         return inject_error(bs, cb, opaque, rule);
404     }
405 
406     return bdrv_aio_readv(bs->file, sector_num, qiov, nb_sectors, cb, opaque);
407 }
408 
409 static BlockDriverAIOCB *blkdebug_aio_writev(BlockDriverState *bs,
410     int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
411     BlockDriverCompletionFunc *cb, void *opaque)
412 {
413     BDRVBlkdebugState *s = bs->opaque;
414     BlkdebugRule *rule = NULL;
415 
416     QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
417         if (rule->options.inject.sector == -1 ||
418             (rule->options.inject.sector >= sector_num &&
419              rule->options.inject.sector < sector_num + nb_sectors)) {
420             break;
421         }
422     }
423 
424     if (rule && rule->options.inject.error) {
425         return inject_error(bs, cb, opaque, rule);
426     }
427 
428     return bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors, cb, opaque);
429 }
430 
431 
432 static void blkdebug_close(BlockDriverState *bs)
433 {
434     BDRVBlkdebugState *s = bs->opaque;
435     BlkdebugRule *rule, *next;
436     int i;
437 
438     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
439         QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {
440             remove_rule(rule);
441         }
442     }
443 }
444 
445 static void suspend_request(BlockDriverState *bs, BlkdebugRule *rule)
446 {
447     BDRVBlkdebugState *s = bs->opaque;
448     BlkdebugSuspendedReq r;
449 
450     r = (BlkdebugSuspendedReq) {
451         .co         = qemu_coroutine_self(),
452         .tag        = g_strdup(rule->options.suspend.tag),
453     };
454 
455     remove_rule(rule);
456     QLIST_INSERT_HEAD(&s->suspended_reqs, &r, next);
457 
458     printf("blkdebug: Suspended request '%s'\n", r.tag);
459     qemu_coroutine_yield();
460     printf("blkdebug: Resuming request '%s'\n", r.tag);
461 
462     QLIST_REMOVE(&r, next);
463     g_free(r.tag);
464 }
465 
466 static bool process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
467     bool injected)
468 {
469     BDRVBlkdebugState *s = bs->opaque;
470 
471     /* Only process rules for the current state */
472     if (rule->state && rule->state != s->state) {
473         return injected;
474     }
475 
476     /* Take the action */
477     switch (rule->action) {
478     case ACTION_INJECT_ERROR:
479         if (!injected) {
480             QSIMPLEQ_INIT(&s->active_rules);
481             injected = true;
482         }
483         QSIMPLEQ_INSERT_HEAD(&s->active_rules, rule, active_next);
484         break;
485 
486     case ACTION_SET_STATE:
487         s->new_state = rule->options.set_state.new_state;
488         break;
489 
490     case ACTION_SUSPEND:
491         suspend_request(bs, rule);
492         break;
493     }
494     return injected;
495 }
496 
497 static void blkdebug_debug_event(BlockDriverState *bs, BlkDebugEvent event)
498 {
499     BDRVBlkdebugState *s = bs->opaque;
500     struct BlkdebugRule *rule, *next;
501     bool injected;
502 
503     assert((int)event >= 0 && event < BLKDBG_EVENT_MAX);
504 
505     injected = false;
506     s->new_state = s->state;
507     QLIST_FOREACH_SAFE(rule, &s->rules[event], next, next) {
508         injected = process_rule(bs, rule, injected);
509     }
510     s->state = s->new_state;
511 }
512 
513 static int blkdebug_debug_breakpoint(BlockDriverState *bs, const char *event,
514                                      const char *tag)
515 {
516     BDRVBlkdebugState *s = bs->opaque;
517     struct BlkdebugRule *rule;
518     BlkDebugEvent blkdebug_event;
519 
520     if (get_event_by_name(event, &blkdebug_event) < 0) {
521         return -ENOENT;
522     }
523 
524 
525     rule = g_malloc(sizeof(*rule));
526     *rule = (struct BlkdebugRule) {
527         .event  = blkdebug_event,
528         .action = ACTION_SUSPEND,
529         .state  = 0,
530         .options.suspend.tag = g_strdup(tag),
531     };
532 
533     QLIST_INSERT_HEAD(&s->rules[blkdebug_event], rule, next);
534 
535     return 0;
536 }
537 
538 static int blkdebug_debug_resume(BlockDriverState *bs, const char *tag)
539 {
540     BDRVBlkdebugState *s = bs->opaque;
541     BlkdebugSuspendedReq *r;
542 
543     QLIST_FOREACH(r, &s->suspended_reqs, next) {
544         if (!strcmp(r->tag, tag)) {
545             qemu_coroutine_enter(r->co, NULL);
546             return 0;
547         }
548     }
549     return -ENOENT;
550 }
551 
552 
553 static bool blkdebug_debug_is_suspended(BlockDriverState *bs, const char *tag)
554 {
555     BDRVBlkdebugState *s = bs->opaque;
556     BlkdebugSuspendedReq *r;
557 
558     QLIST_FOREACH(r, &s->suspended_reqs, next) {
559         if (!strcmp(r->tag, tag)) {
560             return true;
561         }
562     }
563     return false;
564 }
565 
566 static int64_t blkdebug_getlength(BlockDriverState *bs)
567 {
568     return bdrv_getlength(bs->file);
569 }
570 
571 static BlockDriver bdrv_blkdebug = {
572     .format_name        = "blkdebug",
573     .protocol_name      = "blkdebug",
574 
575     .instance_size      = sizeof(BDRVBlkdebugState),
576 
577     .bdrv_file_open     = blkdebug_open,
578     .bdrv_close         = blkdebug_close,
579     .bdrv_getlength     = blkdebug_getlength,
580 
581     .bdrv_aio_readv     = blkdebug_aio_readv,
582     .bdrv_aio_writev    = blkdebug_aio_writev,
583 
584     .bdrv_debug_event           = blkdebug_debug_event,
585     .bdrv_debug_breakpoint      = blkdebug_debug_breakpoint,
586     .bdrv_debug_resume          = blkdebug_debug_resume,
587     .bdrv_debug_is_suspended    = blkdebug_debug_is_suspended,
588 };
589 
590 static void bdrv_blkdebug_init(void)
591 {
592     bdrv_register(&bdrv_blkdebug);
593 }
594 
595 block_init(bdrv_blkdebug_init);
596