/* * Write logging blk driver based on blkverify and blkdebug. * * Copyright (c) 2017 Tuomas Tynkkynen <tuomas@tuxera.com> * Copyright (c) 2018 Aapo Vienamo <aapo@tuxera.com> * Copyright (c) 2018 Ari Sundholm <ari@tuxera.com> * * This work is licensed under the terms of the GNU GPL, version 2 or later. * See the COPYING file in the top-level directory. */ #include "qemu/osdep.h" #include "qapi/error.h" #include "qemu/sockets.h" /* for EINPROGRESS on Windows */ #include "block/block_int.h" #include "qapi/qmp/qdict.h" #include "qapi/qmp/qstring.h" #include "qemu/cutils.h" #include "qemu/module.h" #include "qemu/option.h" /* Disk format stuff - taken from Linux drivers/md/dm-log-writes.c */ #define LOG_FLUSH_FLAG (1 << 0) #define LOG_FUA_FLAG (1 << 1) #define LOG_DISCARD_FLAG (1 << 2) #define LOG_MARK_FLAG (1 << 3) #define LOG_FLAG_MASK (LOG_FLUSH_FLAG \ | LOG_FUA_FLAG \ | LOG_DISCARD_FLAG \ | LOG_MARK_FLAG) #define WRITE_LOG_VERSION 1ULL #define WRITE_LOG_MAGIC 0x6a736677736872ULL /* All fields are little-endian. */ struct log_write_super { uint64_t magic; uint64_t version; uint64_t nr_entries; uint32_t sectorsize; } QEMU_PACKED; struct log_write_entry { uint64_t sector; uint64_t nr_sectors; uint64_t flags; uint64_t data_len; } QEMU_PACKED; /* End of disk format structures. */ typedef struct { BdrvChild *log_file; uint32_t sectorsize; uint32_t sectorbits; uint64_t cur_log_sector; uint64_t nr_entries; uint64_t update_interval; } BDRVBlkLogWritesState; static QemuOptsList runtime_opts = { .name = "blklogwrites", .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head), .desc = { { .name = "log-append", .type = QEMU_OPT_BOOL, .help = "Append to an existing log", }, { .name = "log-sector-size", .type = QEMU_OPT_SIZE, .help = "Log sector size", }, { .name = "log-super-update-interval", .type = QEMU_OPT_NUMBER, .help = "Log superblock update interval (# of write requests)", }, { /* end of list */ } }, }; static inline uint32_t blk_log_writes_log2(uint32_t value) { assert(value > 0); return 31 - clz32(value); } static inline bool blk_log_writes_sector_size_valid(uint32_t sector_size) { return is_power_of_2(sector_size) && sector_size >= sizeof(struct log_write_super) && sector_size >= sizeof(struct log_write_entry) && sector_size < (1ull << 24); } static uint64_t blk_log_writes_find_cur_log_sector(BdrvChild *log, uint32_t sector_size, uint64_t nr_entries, Error **errp) { uint64_t cur_sector = 1; uint64_t cur_idx = 0; uint32_t sector_bits = blk_log_writes_log2(sector_size); struct log_write_entry cur_entry; while (cur_idx < nr_entries) { int read_ret = bdrv_pread(log, cur_sector << sector_bits, &cur_entry, sizeof(cur_entry)); if (read_ret < 0) { error_setg_errno(errp, -read_ret, "Failed to read log entry %"PRIu64, cur_idx); return (uint64_t)-1ull; } if (cur_entry.flags & ~cpu_to_le64(LOG_FLAG_MASK)) { error_setg(errp, "Invalid flags 0x%"PRIx64" in log entry %"PRIu64, le64_to_cpu(cur_entry.flags), cur_idx); return (uint64_t)-1ull; } /* Account for the sector of the entry itself */ ++cur_sector; /* * Account for the data of the write. * For discards, this data is not present. */ if (!(cur_entry.flags & cpu_to_le64(LOG_DISCARD_FLAG))) { cur_sector += le64_to_cpu(cur_entry.nr_sectors); } ++cur_idx; } return cur_sector; } static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { BDRVBlkLogWritesState *s = bs->opaque; QemuOpts *opts; Error *local_err = NULL; int ret; uint64_t log_sector_size; bool log_append; opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort); if (!qemu_opts_absorb_qdict(opts, options, errp)) { ret = -EINVAL; goto fail; } /* Open the file */ bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds, BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, false, &local_err); if (local_err) { ret = -EINVAL; error_propagate(errp, local_err); goto fail; } /* Open the log file */ s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_of_bds, BDRV_CHILD_METADATA, false, &local_err); if (local_err) { ret = -EINVAL; error_propagate(errp, local_err); goto fail; } log_append = qemu_opt_get_bool(opts, "log-append", false); if (log_append) { struct log_write_super log_sb = { 0, 0, 0, 0 }; if (qemu_opt_find(opts, "log-sector-size")) { ret = -EINVAL; error_setg(errp, "log-append and log-sector-size are mutually " "exclusive"); goto fail_log; } /* Read log superblock or fake one for an empty log */ if (!bdrv_getlength(s->log_file->bs)) { log_sb.magic = cpu_to_le64(WRITE_LOG_MAGIC); log_sb.version = cpu_to_le64(WRITE_LOG_VERSION); log_sb.nr_entries = cpu_to_le64(0); log_sb.sectorsize = cpu_to_le32(BDRV_SECTOR_SIZE); } else { ret = bdrv_pread(s->log_file, 0, &log_sb, sizeof(log_sb)); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read log superblock"); goto fail_log; } } if (log_sb.magic != cpu_to_le64(WRITE_LOG_MAGIC)) { ret = -EINVAL; error_setg(errp, "Invalid log superblock magic"); goto fail_log; } if (log_sb.version != cpu_to_le64(WRITE_LOG_VERSION)) { ret = -EINVAL; error_setg(errp, "Unsupported log version %"PRIu64, le64_to_cpu(log_sb.version)); goto fail_log; } log_sector_size = le32_to_cpu(log_sb.sectorsize); s->cur_log_sector = 1; s->nr_entries = 0; if (blk_log_writes_sector_size_valid(log_sector_size)) { s->cur_log_sector = blk_log_writes_find_cur_log_sector(s->log_file, log_sector_size, le64_to_cpu(log_sb.nr_entries), &local_err); if (local_err) { ret = -EINVAL; error_propagate(errp, local_err); goto fail_log; } s->nr_entries = le64_to_cpu(log_sb.nr_entries); } } else { log_sector_size = qemu_opt_get_size(opts, "log-sector-size", BDRV_SECTOR_SIZE); s->cur_log_sector = 1; s->nr_entries = 0; } if (!blk_log_writes_sector_size_valid(log_sector_size)) { ret = -EINVAL; error_setg(errp, "Invalid log sector size %"PRIu64, log_sector_size); goto fail_log; } s->sectorsize = log_sector_size; s->sectorbits = blk_log_writes_log2(log_sector_size); s->update_interval = qemu_opt_get_number(opts, "log-super-update-interval", 4096); if (!s->update_interval) { ret = -EINVAL; error_setg(errp, "Invalid log superblock update interval %"PRIu64, s->update_interval); goto fail_log; } ret = 0; fail_log: if (ret < 0) { bdrv_unref_child(bs, s->log_file); s->log_file = NULL; } fail: if (ret < 0) { bdrv_unref_child(bs, bs->file); bs->file = NULL; } qemu_opts_del(opts); return ret; } static void blk_log_writes_close(BlockDriverState *bs) { BDRVBlkLogWritesState *s = bs->opaque; bdrv_unref_child(bs, s->log_file); s->log_file = NULL; } static int64_t blk_log_writes_getlength(BlockDriverState *bs) { return bdrv_getlength(bs->file->bs); } static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c, BdrvChildRole role, BlockReopenQueue *ro_q, uint64_t perm, uint64_t shrd, uint64_t *nperm, uint64_t *nshrd) { if (!c) { *nperm = perm & DEFAULT_PERM_PASSTHROUGH; *nshrd = (shrd & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED; return; } bdrv_default_perms(bs, c, role, ro_q, perm, shrd, nperm, nshrd); } static void blk_log_writes_refresh_limits(BlockDriverState *bs, Error **errp) { BDRVBlkLogWritesState *s = bs->opaque; bs->bl.request_alignment = s->sectorsize; } static int coroutine_fn blk_log_writes_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) { return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags); } typedef struct BlkLogWritesFileReq { BlockDriverState *bs; uint64_t offset; uint64_t bytes; int file_flags; QEMUIOVector *qiov; int (*func)(struct BlkLogWritesFileReq *r); int file_ret; } BlkLogWritesFileReq; typedef struct { BlockDriverState *bs; QEMUIOVector *qiov; struct log_write_entry entry; uint64_t zero_size; int log_ret; } BlkLogWritesLogReq; static void coroutine_fn blk_log_writes_co_do_log(BlkLogWritesLogReq *lr) { BDRVBlkLogWritesState *s = lr->bs->opaque; uint64_t cur_log_offset = s->cur_log_sector << s->sectorbits; s->nr_entries++; s->cur_log_sector += ROUND_UP(lr->qiov->size, s->sectorsize) >> s->sectorbits; lr->log_ret = bdrv_co_pwritev(s->log_file, cur_log_offset, lr->qiov->size, lr->qiov, 0); /* Logging for the "write zeroes" operation */ if (lr->log_ret == 0 && lr->zero_size) { cur_log_offset = s->cur_log_sector << s->sectorbits; s->cur_log_sector += ROUND_UP(lr->zero_size, s->sectorsize) >> s->sectorbits; lr->log_ret = bdrv_co_pwrite_zeroes(s->log_file, cur_log_offset, lr->zero_size, 0); } /* Update super block on flush or every update interval */ if (lr->log_ret == 0 && ((lr->entry.flags & LOG_FLUSH_FLAG) || (s->nr_entries % s->update_interval == 0))) { struct log_write_super super = { .magic = cpu_to_le64(WRITE_LOG_MAGIC), .version = cpu_to_le64(WRITE_LOG_VERSION), .nr_entries = cpu_to_le64(s->nr_entries), .sectorsize = cpu_to_le32(s->sectorsize), }; void *zeroes = g_malloc0(s->sectorsize - sizeof(super)); QEMUIOVector qiov; qemu_iovec_init(&qiov, 2); qemu_iovec_add(&qiov, &super, sizeof(super)); qemu_iovec_add(&qiov, zeroes, s->sectorsize - sizeof(super)); lr->log_ret = bdrv_co_pwritev(s->log_file, 0, s->sectorsize, &qiov, 0); if (lr->log_ret == 0) { lr->log_ret = bdrv_co_flush(s->log_file->bs); } qemu_iovec_destroy(&qiov); g_free(zeroes); } } static void coroutine_fn blk_log_writes_co_do_file(BlkLogWritesFileReq *fr) { fr->file_ret = fr->func(fr); } static int coroutine_fn blk_log_writes_co_log(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags, int (*file_func)(BlkLogWritesFileReq *r), uint64_t entry_flags, bool is_zero_write) { QEMUIOVector log_qiov; size_t niov = qiov ? qiov->niov : 0; BDRVBlkLogWritesState *s = bs->opaque; BlkLogWritesFileReq fr = { .bs = bs, .offset = offset, .bytes = bytes, .file_flags = flags, .qiov = qiov, .func = file_func, }; BlkLogWritesLogReq lr = { .bs = bs, .qiov = &log_qiov, .entry = { .sector = cpu_to_le64(offset >> s->sectorbits), .nr_sectors = cpu_to_le64(bytes >> s->sectorbits), .flags = cpu_to_le64(entry_flags), .data_len = 0, }, .zero_size = is_zero_write ? bytes : 0, }; void *zeroes = g_malloc0(s->sectorsize - sizeof(lr.entry)); assert((1 << s->sectorbits) == s->sectorsize); assert(bs->bl.request_alignment == s->sectorsize); assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment)); assert(QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment)); qemu_iovec_init(&log_qiov, niov + 2); qemu_iovec_add(&log_qiov, &lr.entry, sizeof(lr.entry)); qemu_iovec_add(&log_qiov, zeroes, s->sectorsize - sizeof(lr.entry)); if (qiov) { qemu_iovec_concat(&log_qiov, qiov, 0, qiov->size); } blk_log_writes_co_do_file(&fr); blk_log_writes_co_do_log(&lr); qemu_iovec_destroy(&log_qiov); g_free(zeroes); if (lr.log_ret < 0) { return lr.log_ret; } return fr.file_ret; } static int coroutine_fn blk_log_writes_co_do_file_pwritev(BlkLogWritesFileReq *fr) { return bdrv_co_pwritev(fr->bs->file, fr->offset, fr->bytes, fr->qiov, fr->file_flags); } static int coroutine_fn blk_log_writes_co_do_file_pwrite_zeroes(BlkLogWritesFileReq *fr) { return bdrv_co_pwrite_zeroes(fr->bs->file, fr->offset, fr->bytes, fr->file_flags); } static int coroutine_fn blk_log_writes_co_do_file_flush(BlkLogWritesFileReq *fr) { return bdrv_co_flush(fr->bs->file->bs); } static int coroutine_fn blk_log_writes_co_do_file_pdiscard(BlkLogWritesFileReq *fr) { return bdrv_co_pdiscard(fr->bs->file, fr->offset, fr->bytes); } static int coroutine_fn blk_log_writes_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) { return blk_log_writes_co_log(bs, offset, bytes, qiov, flags, blk_log_writes_co_do_file_pwritev, 0, false); } static int coroutine_fn blk_log_writes_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int bytes, BdrvRequestFlags flags) { return blk_log_writes_co_log(bs, offset, bytes, NULL, flags, blk_log_writes_co_do_file_pwrite_zeroes, 0, true); } static int coroutine_fn blk_log_writes_co_flush_to_disk(BlockDriverState *bs) { return blk_log_writes_co_log(bs, 0, 0, NULL, 0, blk_log_writes_co_do_file_flush, LOG_FLUSH_FLAG, false); } static int coroutine_fn blk_log_writes_co_pdiscard(BlockDriverState *bs, int64_t offset, int count) { return blk_log_writes_co_log(bs, offset, count, NULL, 0, blk_log_writes_co_do_file_pdiscard, LOG_DISCARD_FLAG, false); } static const char *const blk_log_writes_strong_runtime_opts[] = { "log-append", "log-sector-size", NULL }; static BlockDriver bdrv_blk_log_writes = { .format_name = "blklogwrites", .instance_size = sizeof(BDRVBlkLogWritesState), .bdrv_open = blk_log_writes_open, .bdrv_close = blk_log_writes_close, .bdrv_getlength = blk_log_writes_getlength, .bdrv_child_perm = blk_log_writes_child_perm, .bdrv_refresh_limits = blk_log_writes_refresh_limits, .bdrv_co_preadv = blk_log_writes_co_preadv, .bdrv_co_pwritev = blk_log_writes_co_pwritev, .bdrv_co_pwrite_zeroes = blk_log_writes_co_pwrite_zeroes, .bdrv_co_flush_to_disk = blk_log_writes_co_flush_to_disk, .bdrv_co_pdiscard = blk_log_writes_co_pdiscard, .is_filter = true, .strong_runtime_opts = blk_log_writes_strong_runtime_opts, }; static void bdrv_blk_log_writes_init(void) { bdrv_register(&bdrv_blk_log_writes); } block_init(bdrv_blk_log_writes_init);