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