xref: /openbmc/qemu/block/blkverify.c (revision 1f32989d)
1 /*
2  * Block protocol for block driver correctness testing
3  *
4  * Copyright (C) 2010 IBM, Corp.
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 #include <stdarg.h>
11 #include "qemu_socket.h" /* for EINPROGRESS on Windows */
12 #include "block_int.h"
13 
14 typedef struct {
15     BlockDriverState *test_file;
16 } BDRVBlkverifyState;
17 
18 typedef struct BlkverifyAIOCB BlkverifyAIOCB;
19 struct BlkverifyAIOCB {
20     BlockDriverAIOCB common;
21     QEMUBH *bh;
22 
23     /* Request metadata */
24     bool is_write;
25     int64_t sector_num;
26     int nb_sectors;
27 
28     int ret;                    /* first completed request's result */
29     unsigned int done;          /* completion counter */
30     bool *finished;             /* completion signal for cancel */
31 
32     QEMUIOVector *qiov;         /* user I/O vector */
33     QEMUIOVector raw_qiov;      /* cloned I/O vector for raw file */
34     void *buf;                  /* buffer for raw file I/O */
35 
36     void (*verify)(BlkverifyAIOCB *acb);
37 };
38 
39 static void blkverify_aio_cancel(BlockDriverAIOCB *blockacb)
40 {
41     BlkverifyAIOCB *acb = (BlkverifyAIOCB *)blockacb;
42     bool finished = false;
43 
44     /* Wait until request completes, invokes its callback, and frees itself */
45     acb->finished = &finished;
46     while (!finished) {
47         qemu_aio_wait();
48     }
49 }
50 
51 static const AIOCBInfo blkverify_aiocb_info = {
52     .aiocb_size         = sizeof(BlkverifyAIOCB),
53     .cancel             = blkverify_aio_cancel,
54 };
55 
56 static void GCC_FMT_ATTR(2, 3) blkverify_err(BlkverifyAIOCB *acb,
57                                              const char *fmt, ...)
58 {
59     va_list ap;
60 
61     va_start(ap, fmt);
62     fprintf(stderr, "blkverify: %s sector_num=%" PRId64 " nb_sectors=%d ",
63             acb->is_write ? "write" : "read", acb->sector_num,
64             acb->nb_sectors);
65     vfprintf(stderr, fmt, ap);
66     fprintf(stderr, "\n");
67     va_end(ap);
68     exit(1);
69 }
70 
71 /* Valid blkverify filenames look like blkverify:path/to/raw_image:path/to/image */
72 static int blkverify_open(BlockDriverState *bs, const char *filename, int flags)
73 {
74     BDRVBlkverifyState *s = bs->opaque;
75     int ret;
76     char *raw, *c;
77 
78     /* Parse the blkverify: prefix */
79     if (strncmp(filename, "blkverify:", strlen("blkverify:"))) {
80         return -EINVAL;
81     }
82     filename += strlen("blkverify:");
83 
84     /* Parse the raw image filename */
85     c = strchr(filename, ':');
86     if (c == NULL) {
87         return -EINVAL;
88     }
89 
90     raw = g_strdup(filename);
91     raw[c - filename] = '\0';
92     ret = bdrv_file_open(&bs->file, raw, flags);
93     g_free(raw);
94     if (ret < 0) {
95         return ret;
96     }
97     filename = c + 1;
98 
99     /* Open the test file */
100     s->test_file = bdrv_new("");
101     ret = bdrv_open(s->test_file, filename, flags, NULL);
102     if (ret < 0) {
103         bdrv_delete(s->test_file);
104         s->test_file = NULL;
105         return ret;
106     }
107 
108     return 0;
109 }
110 
111 static void blkverify_close(BlockDriverState *bs)
112 {
113     BDRVBlkverifyState *s = bs->opaque;
114 
115     bdrv_delete(s->test_file);
116     s->test_file = NULL;
117 }
118 
119 static int64_t blkverify_getlength(BlockDriverState *bs)
120 {
121     BDRVBlkverifyState *s = bs->opaque;
122 
123     return bdrv_getlength(s->test_file);
124 }
125 
126 /**
127  * Check that I/O vector contents are identical
128  *
129  * @a:          I/O vector
130  * @b:          I/O vector
131  * @ret:        Offset to first mismatching byte or -1 if match
132  */
133 static ssize_t blkverify_iovec_compare(QEMUIOVector *a, QEMUIOVector *b)
134 {
135     int i;
136     ssize_t offset = 0;
137 
138     assert(a->niov == b->niov);
139     for (i = 0; i < a->niov; i++) {
140         size_t len = 0;
141         uint8_t *p = (uint8_t *)a->iov[i].iov_base;
142         uint8_t *q = (uint8_t *)b->iov[i].iov_base;
143 
144         assert(a->iov[i].iov_len == b->iov[i].iov_len);
145         while (len < a->iov[i].iov_len && *p++ == *q++) {
146             len++;
147         }
148 
149         offset += len;
150 
151         if (len != a->iov[i].iov_len) {
152             return offset;
153         }
154     }
155     return -1;
156 }
157 
158 typedef struct {
159     int src_index;
160     struct iovec *src_iov;
161     void *dest_base;
162 } IOVectorSortElem;
163 
164 static int sortelem_cmp_src_base(const void *a, const void *b)
165 {
166     const IOVectorSortElem *elem_a = a;
167     const IOVectorSortElem *elem_b = b;
168 
169     /* Don't overflow */
170     if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) {
171         return -1;
172     } else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) {
173         return 1;
174     } else {
175         return 0;
176     }
177 }
178 
179 static int sortelem_cmp_src_index(const void *a, const void *b)
180 {
181     const IOVectorSortElem *elem_a = a;
182     const IOVectorSortElem *elem_b = b;
183 
184     return elem_a->src_index - elem_b->src_index;
185 }
186 
187 /**
188  * Copy contents of I/O vector
189  *
190  * The relative relationships of overlapping iovecs are preserved.  This is
191  * necessary to ensure identical semantics in the cloned I/O vector.
192  */
193 static void blkverify_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src,
194                                   void *buf)
195 {
196     IOVectorSortElem sortelems[src->niov];
197     void *last_end;
198     int i;
199 
200     /* Sort by source iovecs by base address */
201     for (i = 0; i < src->niov; i++) {
202         sortelems[i].src_index = i;
203         sortelems[i].src_iov = &src->iov[i];
204     }
205     qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base);
206 
207     /* Allocate buffer space taking into account overlapping iovecs */
208     last_end = NULL;
209     for (i = 0; i < src->niov; i++) {
210         struct iovec *cur = sortelems[i].src_iov;
211         ptrdiff_t rewind = 0;
212 
213         /* Detect overlap */
214         if (last_end && last_end > cur->iov_base) {
215             rewind = last_end - cur->iov_base;
216         }
217 
218         sortelems[i].dest_base = buf - rewind;
219         buf += cur->iov_len - MIN(rewind, cur->iov_len);
220         last_end = MAX(cur->iov_base + cur->iov_len, last_end);
221     }
222 
223     /* Sort by source iovec index and build destination iovec */
224     qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index);
225     for (i = 0; i < src->niov; i++) {
226         qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len);
227     }
228 }
229 
230 static BlkverifyAIOCB *blkverify_aio_get(BlockDriverState *bs, bool is_write,
231                                          int64_t sector_num, QEMUIOVector *qiov,
232                                          int nb_sectors,
233                                          BlockDriverCompletionFunc *cb,
234                                          void *opaque)
235 {
236     BlkverifyAIOCB *acb = qemu_aio_get(&blkverify_aiocb_info, bs, cb, opaque);
237 
238     acb->bh = NULL;
239     acb->is_write = is_write;
240     acb->sector_num = sector_num;
241     acb->nb_sectors = nb_sectors;
242     acb->ret = -EINPROGRESS;
243     acb->done = 0;
244     acb->qiov = qiov;
245     acb->buf = NULL;
246     acb->verify = NULL;
247     acb->finished = NULL;
248     return acb;
249 }
250 
251 static void blkverify_aio_bh(void *opaque)
252 {
253     BlkverifyAIOCB *acb = opaque;
254 
255     qemu_bh_delete(acb->bh);
256     if (acb->buf) {
257         qemu_iovec_destroy(&acb->raw_qiov);
258         qemu_vfree(acb->buf);
259     }
260     acb->common.cb(acb->common.opaque, acb->ret);
261     if (acb->finished) {
262         *acb->finished = true;
263     }
264     qemu_aio_release(acb);
265 }
266 
267 static void blkverify_aio_cb(void *opaque, int ret)
268 {
269     BlkverifyAIOCB *acb = opaque;
270 
271     switch (++acb->done) {
272     case 1:
273         acb->ret = ret;
274         break;
275 
276     case 2:
277         if (acb->ret != ret) {
278             blkverify_err(acb, "return value mismatch %d != %d", acb->ret, ret);
279         }
280 
281         if (acb->verify) {
282             acb->verify(acb);
283         }
284 
285         acb->bh = qemu_bh_new(blkverify_aio_bh, acb);
286         qemu_bh_schedule(acb->bh);
287         break;
288     }
289 }
290 
291 static void blkverify_verify_readv(BlkverifyAIOCB *acb)
292 {
293     ssize_t offset = blkverify_iovec_compare(acb->qiov, &acb->raw_qiov);
294     if (offset != -1) {
295         blkverify_err(acb, "contents mismatch in sector %" PRId64,
296                       acb->sector_num + (int64_t)(offset / BDRV_SECTOR_SIZE));
297     }
298 }
299 
300 static BlockDriverAIOCB *blkverify_aio_readv(BlockDriverState *bs,
301         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
302         BlockDriverCompletionFunc *cb, void *opaque)
303 {
304     BDRVBlkverifyState *s = bs->opaque;
305     BlkverifyAIOCB *acb = blkverify_aio_get(bs, false, sector_num, qiov,
306                                             nb_sectors, cb, opaque);
307 
308     acb->verify = blkverify_verify_readv;
309     acb->buf = qemu_blockalign(bs->file, qiov->size);
310     qemu_iovec_init(&acb->raw_qiov, acb->qiov->niov);
311     blkverify_iovec_clone(&acb->raw_qiov, qiov, acb->buf);
312 
313     bdrv_aio_readv(s->test_file, sector_num, qiov, nb_sectors,
314                    blkverify_aio_cb, acb);
315     bdrv_aio_readv(bs->file, sector_num, &acb->raw_qiov, nb_sectors,
316                    blkverify_aio_cb, acb);
317     return &acb->common;
318 }
319 
320 static BlockDriverAIOCB *blkverify_aio_writev(BlockDriverState *bs,
321         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
322         BlockDriverCompletionFunc *cb, void *opaque)
323 {
324     BDRVBlkverifyState *s = bs->opaque;
325     BlkverifyAIOCB *acb = blkverify_aio_get(bs, true, sector_num, qiov,
326                                             nb_sectors, cb, opaque);
327 
328     bdrv_aio_writev(s->test_file, sector_num, qiov, nb_sectors,
329                     blkverify_aio_cb, acb);
330     bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors,
331                     blkverify_aio_cb, acb);
332     return &acb->common;
333 }
334 
335 static BlockDriverAIOCB *blkverify_aio_flush(BlockDriverState *bs,
336                                              BlockDriverCompletionFunc *cb,
337                                              void *opaque)
338 {
339     BDRVBlkverifyState *s = bs->opaque;
340 
341     /* Only flush test file, the raw file is not important */
342     return bdrv_aio_flush(s->test_file, cb, opaque);
343 }
344 
345 static BlockDriver bdrv_blkverify = {
346     .format_name        = "blkverify",
347     .protocol_name      = "blkverify",
348 
349     .instance_size      = sizeof(BDRVBlkverifyState),
350 
351     .bdrv_getlength     = blkverify_getlength,
352 
353     .bdrv_file_open     = blkverify_open,
354     .bdrv_close         = blkverify_close,
355 
356     .bdrv_aio_readv     = blkverify_aio_readv,
357     .bdrv_aio_writev    = blkverify_aio_writev,
358     .bdrv_aio_flush     = blkverify_aio_flush,
359 };
360 
361 static void bdrv_blkverify_init(void)
362 {
363     bdrv_register(&bdrv_blkverify);
364 }
365 
366 block_init(bdrv_blkverify_init);
367