1
2
3
4
5
6
7
8
9
10
11
12#include "qemu/osdep.h"
13#include "qapi/error.h"
14#include "qemu/sockets.h"
15#include "block/block-io.h"
16#include "block/block_int.h"
17#include "qapi/qmp/qdict.h"
18#include "qapi/qmp/qstring.h"
19#include "qemu/cutils.h"
20#include "qemu/module.h"
21#include "qemu/option.h"
22
23
24
25#define LOG_FLUSH_FLAG (1 << 0)
26#define LOG_FUA_FLAG (1 << 1)
27#define LOG_DISCARD_FLAG (1 << 2)
28#define LOG_MARK_FLAG (1 << 3)
29#define LOG_FLAG_MASK (LOG_FLUSH_FLAG \
30 | LOG_FUA_FLAG \
31 | LOG_DISCARD_FLAG \
32 | LOG_MARK_FLAG)
33
34#define WRITE_LOG_VERSION 1ULL
35#define WRITE_LOG_MAGIC 0x6a736677736872ULL
36
37
38struct log_write_super {
39 uint64_t magic;
40 uint64_t version;
41 uint64_t nr_entries;
42 uint32_t sectorsize;
43} QEMU_PACKED;
44
45struct log_write_entry {
46 uint64_t sector;
47 uint64_t nr_sectors;
48 uint64_t flags;
49 uint64_t data_len;
50} QEMU_PACKED;
51
52
53
54typedef struct {
55 BdrvChild *log_file;
56 uint32_t sectorsize;
57 uint32_t sectorbits;
58 uint64_t cur_log_sector;
59 uint64_t nr_entries;
60 uint64_t update_interval;
61} BDRVBlkLogWritesState;
62
63static QemuOptsList runtime_opts = {
64 .name = "blklogwrites",
65 .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
66 .desc = {
67 {
68 .name = "log-append",
69 .type = QEMU_OPT_BOOL,
70 .help = "Append to an existing log",
71 },
72 {
73 .name = "log-sector-size",
74 .type = QEMU_OPT_SIZE,
75 .help = "Log sector size",
76 },
77 {
78 .name = "log-super-update-interval",
79 .type = QEMU_OPT_NUMBER,
80 .help = "Log superblock update interval (# of write requests)",
81 },
82 { }
83 },
84};
85
86static inline uint32_t blk_log_writes_log2(uint32_t value)
87{
88 assert(value > 0);
89 return 31 - clz32(value);
90}
91
92static inline bool blk_log_writes_sector_size_valid(uint32_t sector_size)
93{
94 return is_power_of_2(sector_size) &&
95 sector_size >= sizeof(struct log_write_super) &&
96 sector_size >= sizeof(struct log_write_entry) &&
97 sector_size < (1ull << 24);
98}
99
100static uint64_t blk_log_writes_find_cur_log_sector(BdrvChild *log,
101 uint32_t sector_size,
102 uint64_t nr_entries,
103 Error **errp)
104{
105 uint64_t cur_sector = 1;
106 uint64_t cur_idx = 0;
107 uint32_t sector_bits = blk_log_writes_log2(sector_size);
108 struct log_write_entry cur_entry;
109
110 while (cur_idx < nr_entries) {
111 int read_ret = bdrv_pread(log, cur_sector << sector_bits,
112 sizeof(cur_entry), &cur_entry, 0);
113 if (read_ret < 0) {
114 error_setg_errno(errp, -read_ret,
115 "Failed to read log entry %"PRIu64, cur_idx);
116 return (uint64_t)-1ull;
117 }
118
119 if (cur_entry.flags & ~cpu_to_le64(LOG_FLAG_MASK)) {
120 error_setg(errp, "Invalid flags 0x%"PRIx64" in log entry %"PRIu64,
121 le64_to_cpu(cur_entry.flags), cur_idx);
122 return (uint64_t)-1ull;
123 }
124
125
126 ++cur_sector;
127
128
129
130
131
132 if (!(cur_entry.flags & cpu_to_le64(LOG_DISCARD_FLAG))) {
133 cur_sector += le64_to_cpu(cur_entry.nr_sectors);
134 }
135
136 ++cur_idx;
137 }
138
139 return cur_sector;
140}
141
142static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags,
143 Error **errp)
144{
145 BDRVBlkLogWritesState *s = bs->opaque;
146 QemuOpts *opts;
147 Error *local_err = NULL;
148 int ret;
149 uint64_t log_sector_size;
150 bool log_append;
151
152 opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
153 if (!qemu_opts_absorb_qdict(opts, options, errp)) {
154 ret = -EINVAL;
155 goto fail;
156 }
157
158
159 ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
160 if (ret < 0) {
161 goto fail;
162 }
163
164
165 s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_of_bds,
166 BDRV_CHILD_METADATA, false, errp);
167 if (!s->log_file) {
168 ret = -EINVAL;
169 goto fail;
170 }
171
172 log_append = qemu_opt_get_bool(opts, "log-append", false);
173
174 if (log_append) {
175 struct log_write_super log_sb = { 0, 0, 0, 0 };
176
177 if (qemu_opt_find(opts, "log-sector-size")) {
178 ret = -EINVAL;
179 error_setg(errp, "log-append and log-sector-size are mutually "
180 "exclusive");
181 goto fail_log;
182 }
183
184
185 if (!bdrv_getlength(s->log_file->bs)) {
186 log_sb.magic = cpu_to_le64(WRITE_LOG_MAGIC);
187 log_sb.version = cpu_to_le64(WRITE_LOG_VERSION);
188 log_sb.nr_entries = cpu_to_le64(0);
189 log_sb.sectorsize = cpu_to_le32(BDRV_SECTOR_SIZE);
190 } else {
191 ret = bdrv_pread(s->log_file, 0, sizeof(log_sb), &log_sb, 0);
192 if (ret < 0) {
193 error_setg_errno(errp, -ret, "Could not read log superblock");
194 goto fail_log;
195 }
196 }
197
198 if (log_sb.magic != cpu_to_le64(WRITE_LOG_MAGIC)) {
199 ret = -EINVAL;
200 error_setg(errp, "Invalid log superblock magic");
201 goto fail_log;
202 }
203
204 if (log_sb.version != cpu_to_le64(WRITE_LOG_VERSION)) {
205 ret = -EINVAL;
206 error_setg(errp, "Unsupported log version %"PRIu64,
207 le64_to_cpu(log_sb.version));
208 goto fail_log;
209 }
210
211 log_sector_size = le32_to_cpu(log_sb.sectorsize);
212 s->cur_log_sector = 1;
213 s->nr_entries = 0;
214
215 if (blk_log_writes_sector_size_valid(log_sector_size)) {
216 s->cur_log_sector =
217 blk_log_writes_find_cur_log_sector(s->log_file, log_sector_size,
218 le64_to_cpu(log_sb.nr_entries), &local_err);
219 if (local_err) {
220 ret = -EINVAL;
221 error_propagate(errp, local_err);
222 goto fail_log;
223 }
224
225 s->nr_entries = le64_to_cpu(log_sb.nr_entries);
226 }
227 } else {
228 log_sector_size = qemu_opt_get_size(opts, "log-sector-size",
229 BDRV_SECTOR_SIZE);
230 s->cur_log_sector = 1;
231 s->nr_entries = 0;
232 }
233
234 if (!blk_log_writes_sector_size_valid(log_sector_size)) {
235 ret = -EINVAL;
236 error_setg(errp, "Invalid log sector size %"PRIu64, log_sector_size);
237 goto fail_log;
238 }
239
240 s->sectorsize = log_sector_size;
241 s->sectorbits = blk_log_writes_log2(log_sector_size);
242 s->update_interval = qemu_opt_get_number(opts, "log-super-update-interval",
243 4096);
244 if (!s->update_interval) {
245 ret = -EINVAL;
246 error_setg(errp, "Invalid log superblock update interval %"PRIu64,
247 s->update_interval);
248 goto fail_log;
249 }
250
251 ret = 0;
252fail_log:
253 if (ret < 0) {
254 bdrv_unref_child(bs, s->log_file);
255 s->log_file = NULL;
256 }
257fail:
258 qemu_opts_del(opts);
259 return ret;
260}
261
262static void blk_log_writes_close(BlockDriverState *bs)
263{
264 BDRVBlkLogWritesState *s = bs->opaque;
265
266 bdrv_unref_child(bs, s->log_file);
267 s->log_file = NULL;
268}
269
270static int64_t coroutine_fn GRAPH_RDLOCK
271blk_log_writes_co_getlength(BlockDriverState *bs)
272{
273 return bdrv_co_getlength(bs->file->bs);
274}
275
276static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c,
277 BdrvChildRole role,
278 BlockReopenQueue *ro_q,
279 uint64_t perm, uint64_t shrd,
280 uint64_t *nperm, uint64_t *nshrd)
281{
282 if (!c) {
283 *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
284 *nshrd = (shrd & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
285 return;
286 }
287
288 bdrv_default_perms(bs, c, role, ro_q, perm, shrd,
289 nperm, nshrd);
290}
291
292static void blk_log_writes_refresh_limits(BlockDriverState *bs, Error **errp)
293{
294 BDRVBlkLogWritesState *s = bs->opaque;
295 bs->bl.request_alignment = s->sectorsize;
296}
297
298static int coroutine_fn GRAPH_RDLOCK
299blk_log_writes_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
300 QEMUIOVector *qiov, BdrvRequestFlags flags)
301{
302 return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
303}
304
305typedef struct BlkLogWritesFileReq {
306 BlockDriverState *bs;
307 uint64_t offset;
308 uint64_t bytes;
309 int file_flags;
310 QEMUIOVector *qiov;
311 int GRAPH_RDLOCK_PTR (*func)(struct BlkLogWritesFileReq *r);
312 int file_ret;
313} BlkLogWritesFileReq;
314
315typedef struct {
316 BlockDriverState *bs;
317 QEMUIOVector *qiov;
318 struct log_write_entry entry;
319 uint64_t zero_size;
320 int log_ret;
321} BlkLogWritesLogReq;
322
323static void coroutine_fn GRAPH_RDLOCK
324blk_log_writes_co_do_log(BlkLogWritesLogReq *lr)
325{
326 BDRVBlkLogWritesState *s = lr->bs->opaque;
327 uint64_t cur_log_offset = s->cur_log_sector << s->sectorbits;
328
329 s->nr_entries++;
330 s->cur_log_sector +=
331 ROUND_UP(lr->qiov->size, s->sectorsize) >> s->sectorbits;
332
333 lr->log_ret = bdrv_co_pwritev(s->log_file, cur_log_offset, lr->qiov->size,
334 lr->qiov, 0);
335
336
337 if (lr->log_ret == 0 && lr->zero_size) {
338 cur_log_offset = s->cur_log_sector << s->sectorbits;
339 s->cur_log_sector +=
340 ROUND_UP(lr->zero_size, s->sectorsize) >> s->sectorbits;
341
342 lr->log_ret = bdrv_co_pwrite_zeroes(s->log_file, cur_log_offset,
343 lr->zero_size, 0);
344 }
345
346
347 if (lr->log_ret == 0 && ((lr->entry.flags & LOG_FLUSH_FLAG)
348 || (s->nr_entries % s->update_interval == 0)))
349 {
350 struct log_write_super super = {
351 .magic = cpu_to_le64(WRITE_LOG_MAGIC),
352 .version = cpu_to_le64(WRITE_LOG_VERSION),
353 .nr_entries = cpu_to_le64(s->nr_entries),
354 .sectorsize = cpu_to_le32(s->sectorsize),
355 };
356 void *zeroes = g_malloc0(s->sectorsize - sizeof(super));
357 QEMUIOVector qiov;
358
359 qemu_iovec_init(&qiov, 2);
360 qemu_iovec_add(&qiov, &super, sizeof(super));
361 qemu_iovec_add(&qiov, zeroes, s->sectorsize - sizeof(super));
362
363 lr->log_ret =
364 bdrv_co_pwritev(s->log_file, 0, s->sectorsize, &qiov, 0);
365 if (lr->log_ret == 0) {
366 lr->log_ret = bdrv_co_flush(s->log_file->bs);
367 }
368 qemu_iovec_destroy(&qiov);
369 g_free(zeroes);
370 }
371}
372
373static void coroutine_fn GRAPH_RDLOCK
374blk_log_writes_co_do_file(BlkLogWritesFileReq *fr)
375{
376 fr->file_ret = fr->func(fr);
377}
378
379static int coroutine_fn GRAPH_RDLOCK
380blk_log_writes_co_log(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
381 QEMUIOVector *qiov, int flags,
382 int (*file_func)(BlkLogWritesFileReq *r),
383 uint64_t entry_flags, bool is_zero_write)
384{
385 QEMUIOVector log_qiov;
386 size_t niov = qiov ? qiov->niov : 0;
387 BDRVBlkLogWritesState *s = bs->opaque;
388 BlkLogWritesFileReq fr = {
389 .bs = bs,
390 .offset = offset,
391 .bytes = bytes,
392 .file_flags = flags,
393 .qiov = qiov,
394 .func = file_func,
395 };
396 BlkLogWritesLogReq lr = {
397 .bs = bs,
398 .qiov = &log_qiov,
399 .entry = {
400 .sector = cpu_to_le64(offset >> s->sectorbits),
401 .nr_sectors = cpu_to_le64(bytes >> s->sectorbits),
402 .flags = cpu_to_le64(entry_flags),
403 .data_len = 0,
404 },
405 .zero_size = is_zero_write ? bytes : 0,
406 };
407 void *zeroes = g_malloc0(s->sectorsize - sizeof(lr.entry));
408
409 assert((1 << s->sectorbits) == s->sectorsize);
410 assert(bs->bl.request_alignment == s->sectorsize);
411 assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment));
412 assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment));
413
414 qemu_iovec_init(&log_qiov, niov + 2);
415 qemu_iovec_add(&log_qiov, &lr.entry, sizeof(lr.entry));
416 qemu_iovec_add(&log_qiov, zeroes, s->sectorsize - sizeof(lr.entry));
417 if (qiov) {
418 qemu_iovec_concat(&log_qiov, qiov, 0, qiov->size);
419 }
420
421 blk_log_writes_co_do_file(&fr);
422 blk_log_writes_co_do_log(&lr);
423
424 qemu_iovec_destroy(&log_qiov);
425 g_free(zeroes);
426
427 if (lr.log_ret < 0) {
428 return lr.log_ret;
429 }
430
431 return fr.file_ret;
432}
433
434static int coroutine_fn GRAPH_RDLOCK
435blk_log_writes_co_do_file_pwritev(BlkLogWritesFileReq *fr)
436{
437 return bdrv_co_pwritev(fr->bs->file, fr->offset, fr->bytes,
438 fr->qiov, fr->file_flags);
439}
440
441static int coroutine_fn GRAPH_RDLOCK
442blk_log_writes_co_do_file_pwrite_zeroes(BlkLogWritesFileReq *fr)
443{
444 return bdrv_co_pwrite_zeroes(fr->bs->file, fr->offset, fr->bytes,
445 fr->file_flags);
446}
447
448static int coroutine_fn GRAPH_RDLOCK
449blk_log_writes_co_do_file_flush(BlkLogWritesFileReq *fr)
450{
451 return bdrv_co_flush(fr->bs->file->bs);
452}
453
454static int coroutine_fn GRAPH_RDLOCK
455blk_log_writes_co_do_file_pdiscard(BlkLogWritesFileReq *fr)
456{
457 return bdrv_co_pdiscard(fr->bs->file, fr->offset, fr->bytes);
458}
459
460static int coroutine_fn GRAPH_RDLOCK
461blk_log_writes_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
462 QEMUIOVector *qiov, BdrvRequestFlags flags)
463{
464 return blk_log_writes_co_log(bs, offset, bytes, qiov, flags,
465 blk_log_writes_co_do_file_pwritev, 0, false);
466}
467
468static int coroutine_fn GRAPH_RDLOCK
469blk_log_writes_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
470 int64_t bytes, BdrvRequestFlags flags)
471{
472 return blk_log_writes_co_log(bs, offset, bytes, NULL, flags,
473 blk_log_writes_co_do_file_pwrite_zeroes, 0,
474 true);
475}
476
477static int coroutine_fn GRAPH_RDLOCK
478blk_log_writes_co_flush_to_disk(BlockDriverState *bs)
479{
480 return blk_log_writes_co_log(bs, 0, 0, NULL, 0,
481 blk_log_writes_co_do_file_flush,
482 LOG_FLUSH_FLAG, false);
483}
484
485static int coroutine_fn GRAPH_RDLOCK
486blk_log_writes_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes)
487{
488 return blk_log_writes_co_log(bs, offset, bytes, NULL, 0,
489 blk_log_writes_co_do_file_pdiscard,
490 LOG_DISCARD_FLAG, false);
491}
492
493static const char *const blk_log_writes_strong_runtime_opts[] = {
494 "log-append",
495 "log-sector-size",
496
497 NULL
498};
499
500static BlockDriver bdrv_blk_log_writes = {
501 .format_name = "blklogwrites",
502 .instance_size = sizeof(BDRVBlkLogWritesState),
503
504 .bdrv_open = blk_log_writes_open,
505 .bdrv_close = blk_log_writes_close,
506 .bdrv_co_getlength = blk_log_writes_co_getlength,
507 .bdrv_child_perm = blk_log_writes_child_perm,
508 .bdrv_refresh_limits = blk_log_writes_refresh_limits,
509
510 .bdrv_co_preadv = blk_log_writes_co_preadv,
511 .bdrv_co_pwritev = blk_log_writes_co_pwritev,
512 .bdrv_co_pwrite_zeroes = blk_log_writes_co_pwrite_zeroes,
513 .bdrv_co_flush_to_disk = blk_log_writes_co_flush_to_disk,
514 .bdrv_co_pdiscard = blk_log_writes_co_pdiscard,
515
516 .is_filter = true,
517 .strong_runtime_opts = blk_log_writes_strong_runtime_opts,
518};
519
520static void bdrv_blk_log_writes_init(void)
521{
522 bdrv_register(&bdrv_blk_log_writes);
523}
524
525block_init(bdrv_blk_log_writes_init);
526
