2 * Write logging blk driver based on blkverify and blkdebug.
4 * Copyright (c) 2017 Tuomas Tynkkynen <tuomas@tuxera.com>
5 * Copyright (c) 2018 Aapo Vienamo <aapo@tuxera.com>
6 * Copyright (c) 2018 Ari Sundholm <ari@tuxera.com>
8 * This work is licensed under the terms of the GNU GPL, version 2 or later.
9 * See the COPYING file in the top-level directory.
12 #include "qemu/osdep.h"
13 #include "qapi/error.h"
14 #include "qemu/sockets.h" /* for EINPROGRESS on Windows */
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"
23 /* Disk format stuff - taken from Linux drivers/md/dm-log-writes.c */
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 \
34 #define WRITE_LOG_VERSION 1ULL
35 #define WRITE_LOG_MAGIC 0x6a736677736872ULL
37 /* All fields are little-endian. */
38 struct log_write_super {
45 struct log_write_entry {
52 /* End of disk format structures. */
58 uint64_t cur_log_sector;
60 uint64_t update_interval;
61 } BDRVBlkLogWritesState;
63 static QemuOptsList runtime_opts = {
64 .name = "blklogwrites",
65 .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
69 .type = QEMU_OPT_BOOL,
70 .help = "Append to an existing log",
73 .name = "log-sector-size",
74 .type = QEMU_OPT_SIZE,
75 .help = "Log sector size",
78 .name = "log-super-update-interval",
79 .type = QEMU_OPT_NUMBER,
80 .help = "Log superblock update interval (# of write requests)",
86 static inline uint32_t blk_log_writes_log2(uint32_t value)
89 return 31 - clz32(value);
92 static inline bool blk_log_writes_sector_size_valid(uint32_t sector_size)
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);
100 static uint64_t blk_log_writes_find_cur_log_sector(BdrvChild *log,
101 uint32_t sector_size,
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;
110 while (cur_idx < nr_entries) {
111 int read_ret = bdrv_pread(log, cur_sector << sector_bits,
112 sizeof(cur_entry), &cur_entry, 0);
114 error_setg_errno(errp, -read_ret,
115 "Failed to read log entry %"PRIu64, cur_idx);
116 return (uint64_t)-1ull;
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;
125 /* Account for the sector of the entry itself */
129 * Account for the data of the write.
130 * For discards, this data is not present.
132 if (!(cur_entry.flags & cpu_to_le64(LOG_DISCARD_FLAG))) {
133 cur_sector += le64_to_cpu(cur_entry.nr_sectors);
142 static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags,
145 BDRVBlkLogWritesState *s = bs->opaque;
147 Error *local_err = NULL;
149 uint64_t log_sector_size;
152 opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
153 if (!qemu_opts_absorb_qdict(opts, options, errp)) {
159 ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
164 /* Open the log file */
165 s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_of_bds,
166 BDRV_CHILD_METADATA, false, errp);
172 log_append = qemu_opt_get_bool(opts, "log-append", false);
175 struct log_write_super log_sb = { 0, 0, 0, 0 };
177 if (qemu_opt_find(opts, "log-sector-size")) {
179 error_setg(errp, "log-append and log-sector-size are mutually "
184 /* Read log superblock or fake one for an empty log */
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);
191 ret = bdrv_pread(s->log_file, 0, sizeof(log_sb), &log_sb, 0);
193 error_setg_errno(errp, -ret, "Could not read log superblock");
198 if (log_sb.magic != cpu_to_le64(WRITE_LOG_MAGIC)) {
200 error_setg(errp, "Invalid log superblock magic");
204 if (log_sb.version != cpu_to_le64(WRITE_LOG_VERSION)) {
206 error_setg(errp, "Unsupported log version %"PRIu64,
207 le64_to_cpu(log_sb.version));
211 log_sector_size = le32_to_cpu(log_sb.sectorsize);
212 s->cur_log_sector = 1;
215 if (blk_log_writes_sector_size_valid(log_sector_size)) {
217 blk_log_writes_find_cur_log_sector(s->log_file, log_sector_size,
218 le64_to_cpu(log_sb.nr_entries), &local_err);
221 error_propagate(errp, local_err);
225 s->nr_entries = le64_to_cpu(log_sb.nr_entries);
228 log_sector_size = qemu_opt_get_size(opts, "log-sector-size",
230 s->cur_log_sector = 1;
234 if (!blk_log_writes_sector_size_valid(log_sector_size)) {
236 error_setg(errp, "Invalid log sector size %"PRIu64, log_sector_size);
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",
244 if (!s->update_interval) {
246 error_setg(errp, "Invalid log superblock update interval %"PRIu64,
254 bdrv_graph_wrlock(NULL);
255 bdrv_unref_child(bs, s->log_file);
256 bdrv_graph_wrunlock();
264 static void blk_log_writes_close(BlockDriverState *bs)
266 BDRVBlkLogWritesState *s = bs->opaque;
268 bdrv_graph_wrlock(NULL);
269 bdrv_unref_child(bs, s->log_file);
271 bdrv_graph_wrunlock();
274 static int64_t coroutine_fn GRAPH_RDLOCK
275 blk_log_writes_co_getlength(BlockDriverState *bs)
277 return bdrv_co_getlength(bs->file->bs);
280 static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c,
282 BlockReopenQueue *ro_q,
283 uint64_t perm, uint64_t shrd,
284 uint64_t *nperm, uint64_t *nshrd)
287 *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
288 *nshrd = (shrd & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
292 bdrv_default_perms(bs, c, role, ro_q, perm, shrd,
296 static void blk_log_writes_refresh_limits(BlockDriverState *bs, Error **errp)
298 BDRVBlkLogWritesState *s = bs->opaque;
299 bs->bl.request_alignment = s->sectorsize;
302 static int coroutine_fn GRAPH_RDLOCK
303 blk_log_writes_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
304 QEMUIOVector *qiov, BdrvRequestFlags flags)
306 return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
309 typedef struct BlkLogWritesFileReq {
310 BlockDriverState *bs;
315 int GRAPH_RDLOCK_PTR (*func)(struct BlkLogWritesFileReq *r);
317 } BlkLogWritesFileReq;
320 BlockDriverState *bs;
322 struct log_write_entry entry;
325 } BlkLogWritesLogReq;
327 static void coroutine_fn GRAPH_RDLOCK
328 blk_log_writes_co_do_log(BlkLogWritesLogReq *lr)
330 BDRVBlkLogWritesState *s = lr->bs->opaque;
331 uint64_t cur_log_offset = s->cur_log_sector << s->sectorbits;
335 ROUND_UP(lr->qiov->size, s->sectorsize) >> s->sectorbits;
337 lr->log_ret = bdrv_co_pwritev(s->log_file, cur_log_offset, lr->qiov->size,
340 /* Logging for the "write zeroes" operation */
341 if (lr->log_ret == 0 && lr->zero_size) {
342 cur_log_offset = s->cur_log_sector << s->sectorbits;
344 ROUND_UP(lr->zero_size, s->sectorsize) >> s->sectorbits;
346 lr->log_ret = bdrv_co_pwrite_zeroes(s->log_file, cur_log_offset,
350 /* Update super block on flush or every update interval */
351 if (lr->log_ret == 0 && ((lr->entry.flags & LOG_FLUSH_FLAG)
352 || (s->nr_entries % s->update_interval == 0)))
354 struct log_write_super super = {
355 .magic = cpu_to_le64(WRITE_LOG_MAGIC),
356 .version = cpu_to_le64(WRITE_LOG_VERSION),
357 .nr_entries = cpu_to_le64(s->nr_entries),
358 .sectorsize = cpu_to_le32(s->sectorsize),
360 void *zeroes = g_malloc0(s->sectorsize - sizeof(super));
363 qemu_iovec_init(&qiov, 2);
364 qemu_iovec_add(&qiov, &super, sizeof(super));
365 qemu_iovec_add(&qiov, zeroes, s->sectorsize - sizeof(super));
368 bdrv_co_pwritev(s->log_file, 0, s->sectorsize, &qiov, 0);
369 if (lr->log_ret == 0) {
370 lr->log_ret = bdrv_co_flush(s->log_file->bs);
372 qemu_iovec_destroy(&qiov);
377 static void coroutine_fn GRAPH_RDLOCK
378 blk_log_writes_co_do_file(BlkLogWritesFileReq *fr)
380 fr->file_ret = fr->func(fr);
383 static int coroutine_fn GRAPH_RDLOCK
384 blk_log_writes_co_log(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
385 QEMUIOVector *qiov, int flags,
386 int /*GRAPH_RDLOCK*/ (*file_func)(BlkLogWritesFileReq *r),
387 uint64_t entry_flags, bool is_zero_write)
389 QEMUIOVector log_qiov;
390 size_t niov = qiov ? qiov->niov : 0;
391 BDRVBlkLogWritesState *s = bs->opaque;
392 BlkLogWritesFileReq fr = {
400 BlkLogWritesLogReq lr = {
404 .sector = cpu_to_le64(offset >> s->sectorbits),
405 .nr_sectors = cpu_to_le64(bytes >> s->sectorbits),
406 .flags = cpu_to_le64(entry_flags),
409 .zero_size = is_zero_write ? bytes : 0,
411 void *zeroes = g_malloc0(s->sectorsize - sizeof(lr.entry));
413 assert((1 << s->sectorbits) == s->sectorsize);
414 assert(bs->bl.request_alignment == s->sectorsize);
415 assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment));
416 assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment));
418 qemu_iovec_init(&log_qiov, niov + 2);
419 qemu_iovec_add(&log_qiov, &lr.entry, sizeof(lr.entry));
420 qemu_iovec_add(&log_qiov, zeroes, s->sectorsize - sizeof(lr.entry));
422 qemu_iovec_concat(&log_qiov, qiov, 0, qiov->size);
425 blk_log_writes_co_do_file(&fr);
426 blk_log_writes_co_do_log(&lr);
428 qemu_iovec_destroy(&log_qiov);
431 if (lr.log_ret < 0) {
438 static int coroutine_fn GRAPH_RDLOCK
439 blk_log_writes_co_do_file_pwritev(BlkLogWritesFileReq *fr)
441 return bdrv_co_pwritev(fr->bs->file, fr->offset, fr->bytes,
442 fr->qiov, fr->file_flags);
445 static int coroutine_fn GRAPH_RDLOCK
446 blk_log_writes_co_do_file_pwrite_zeroes(BlkLogWritesFileReq *fr)
448 return bdrv_co_pwrite_zeroes(fr->bs->file, fr->offset, fr->bytes,
452 static int coroutine_fn GRAPH_RDLOCK
453 blk_log_writes_co_do_file_flush(BlkLogWritesFileReq *fr)
455 return bdrv_co_flush(fr->bs->file->bs);
458 static int coroutine_fn GRAPH_RDLOCK
459 blk_log_writes_co_do_file_pdiscard(BlkLogWritesFileReq *fr)
461 return bdrv_co_pdiscard(fr->bs->file, fr->offset, fr->bytes);
464 static int coroutine_fn GRAPH_RDLOCK
465 blk_log_writes_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
466 QEMUIOVector *qiov, BdrvRequestFlags flags)
468 return blk_log_writes_co_log(bs, offset, bytes, qiov, flags,
469 blk_log_writes_co_do_file_pwritev, 0, false);
472 static int coroutine_fn GRAPH_RDLOCK
473 blk_log_writes_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
474 int64_t bytes, BdrvRequestFlags flags)
476 return blk_log_writes_co_log(bs, offset, bytes, NULL, flags,
477 blk_log_writes_co_do_file_pwrite_zeroes, 0,
481 static int coroutine_fn GRAPH_RDLOCK
482 blk_log_writes_co_flush_to_disk(BlockDriverState *bs)
484 return blk_log_writes_co_log(bs, 0, 0, NULL, 0,
485 blk_log_writes_co_do_file_flush,
486 LOG_FLUSH_FLAG, false);
489 static int coroutine_fn GRAPH_RDLOCK
490 blk_log_writes_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes)
492 return blk_log_writes_co_log(bs, offset, bytes, NULL, 0,
493 blk_log_writes_co_do_file_pdiscard,
494 LOG_DISCARD_FLAG, false);
497 static const char *const blk_log_writes_strong_runtime_opts[] = {
504 static BlockDriver bdrv_blk_log_writes = {
505 .format_name = "blklogwrites",
506 .instance_size = sizeof(BDRVBlkLogWritesState),
508 .bdrv_open = blk_log_writes_open,
509 .bdrv_close = blk_log_writes_close,
510 .bdrv_co_getlength = blk_log_writes_co_getlength,
511 .bdrv_child_perm = blk_log_writes_child_perm,
512 .bdrv_refresh_limits = blk_log_writes_refresh_limits,
514 .bdrv_co_preadv = blk_log_writes_co_preadv,
515 .bdrv_co_pwritev = blk_log_writes_co_pwritev,
516 .bdrv_co_pwrite_zeroes = blk_log_writes_co_pwrite_zeroes,
517 .bdrv_co_flush_to_disk = blk_log_writes_co_flush_to_disk,
518 .bdrv_co_pdiscard = blk_log_writes_co_pdiscard,
521 .strong_runtime_opts = blk_log_writes_strong_runtime_opts,
524 static void bdrv_blk_log_writes_init(void)
526 bdrv_register(&bdrv_blk_log_writes);
529 block_init(bdrv_blk_log_writes_init);