/* * QEMU Enhanced Disk Format * * Copyright IBM, Corp. 2010 * * Authors: * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> * Anthony Liguori <aliguori@us.ibm.com> * * This work is licensed under the terms of the GNU LGPL, version 2 or later. * See the COPYING.LIB file in the top-level directory. * */ #include "qemu/osdep.h" #include "block/qdict.h" #include "qapi/error.h" #include "qemu/timer.h" #include "qemu/bswap.h" #include "qemu/option.h" #include "trace.h" #include "qed.h" #include "sysemu/block-backend.h" #include "qapi/qmp/qdict.h" #include "qapi/qobject-input-visitor.h" #include "qapi/qapi-visit-block-core.h" static QemuOptsList qed_create_opts; static int bdrv_qed_probe(const uint8_t *buf, int buf_size, const char *filename) { const QEDHeader *header = (const QEDHeader *)buf; if (buf_size < sizeof(*header)) { return 0; } if (le32_to_cpu(header->magic) != QED_MAGIC) { return 0; } return 100; } /** * Check whether an image format is raw * * @fmt: Backing file format, may be NULL */ static bool qed_fmt_is_raw(const char *fmt) { return fmt && strcmp(fmt, "raw") == 0; } static void qed_header_le_to_cpu(const QEDHeader *le, QEDHeader *cpu) { cpu->magic = le32_to_cpu(le->magic); cpu->cluster_size = le32_to_cpu(le->cluster_size); cpu->table_size = le32_to_cpu(le->table_size); cpu->header_size = le32_to_cpu(le->header_size); cpu->features = le64_to_cpu(le->features); cpu->compat_features = le64_to_cpu(le->compat_features); cpu->autoclear_features = le64_to_cpu(le->autoclear_features); cpu->l1_table_offset = le64_to_cpu(le->l1_table_offset); cpu->image_size = le64_to_cpu(le->image_size); cpu->backing_filename_offset = le32_to_cpu(le->backing_filename_offset); cpu->backing_filename_size = le32_to_cpu(le->backing_filename_size); } static void qed_header_cpu_to_le(const QEDHeader *cpu, QEDHeader *le) { le->magic = cpu_to_le32(cpu->magic); le->cluster_size = cpu_to_le32(cpu->cluster_size); le->table_size = cpu_to_le32(cpu->table_size); le->header_size = cpu_to_le32(cpu->header_size); le->features = cpu_to_le64(cpu->features); le->compat_features = cpu_to_le64(cpu->compat_features); le->autoclear_features = cpu_to_le64(cpu->autoclear_features); le->l1_table_offset = cpu_to_le64(cpu->l1_table_offset); le->image_size = cpu_to_le64(cpu->image_size); le->backing_filename_offset = cpu_to_le32(cpu->backing_filename_offset); le->backing_filename_size = cpu_to_le32(cpu->backing_filename_size); } int qed_write_header_sync(BDRVQEDState *s) { QEDHeader le; int ret; qed_header_cpu_to_le(&s->header, &le); ret = bdrv_pwrite(s->bs->file, 0, &le, sizeof(le)); if (ret != sizeof(le)) { return ret; } return 0; } /** * Update header in-place (does not rewrite backing filename or other strings) * * This function only updates known header fields in-place and does not affect * extra data after the QED header. * * No new allocating reqs can start while this function runs. */ static int coroutine_fn qed_write_header(BDRVQEDState *s) { /* We must write full sectors for O_DIRECT but cannot necessarily generate * the data following the header if an unrecognized compat feature is * active. Therefore, first read the sectors containing the header, update * them, and write back. */ int nsectors = DIV_ROUND_UP(sizeof(QEDHeader), BDRV_SECTOR_SIZE); size_t len = nsectors * BDRV_SECTOR_SIZE; uint8_t *buf; struct iovec iov; QEMUIOVector qiov; int ret; assert(s->allocating_acb || s->allocating_write_reqs_plugged); buf = qemu_blockalign(s->bs, len); iov = (struct iovec) { .iov_base = buf, .iov_len = len, }; qemu_iovec_init_external(&qiov, &iov, 1); ret = bdrv_co_preadv(s->bs->file, 0, qiov.size, &qiov, 0); if (ret < 0) { goto out; } /* Update header */ qed_header_cpu_to_le(&s->header, (QEDHeader *) buf); ret = bdrv_co_pwritev(s->bs->file, 0, qiov.size, &qiov, 0); if (ret < 0) { goto out; } ret = 0; out: qemu_vfree(buf); return ret; } static uint64_t qed_max_image_size(uint32_t cluster_size, uint32_t table_size) { uint64_t table_entries; uint64_t l2_size; table_entries = (table_size * cluster_size) / sizeof(uint64_t); l2_size = table_entries * cluster_size; return l2_size * table_entries; } static bool qed_is_cluster_size_valid(uint32_t cluster_size) { if (cluster_size < QED_MIN_CLUSTER_SIZE || cluster_size > QED_MAX_CLUSTER_SIZE) { return false; } if (cluster_size & (cluster_size - 1)) { return false; /* not power of 2 */ } return true; } static bool qed_is_table_size_valid(uint32_t table_size) { if (table_size < QED_MIN_TABLE_SIZE || table_size > QED_MAX_TABLE_SIZE) { return false; } if (table_size & (table_size - 1)) { return false; /* not power of 2 */ } return true; } static bool qed_is_image_size_valid(uint64_t image_size, uint32_t cluster_size, uint32_t table_size) { if (image_size % BDRV_SECTOR_SIZE != 0) { return false; /* not multiple of sector size */ } if (image_size > qed_max_image_size(cluster_size, table_size)) { return false; /* image is too large */ } return true; } /** * Read a string of known length from the image file * * @file: Image file * @offset: File offset to start of string, in bytes * @n: String length in bytes * @buf: Destination buffer * @buflen: Destination buffer length in bytes * @ret: 0 on success, -errno on failure * * The string is NUL-terminated. */ static int qed_read_string(BdrvChild *file, uint64_t offset, size_t n, char *buf, size_t buflen) { int ret; if (n >= buflen) { return -EINVAL; } ret = bdrv_pread(file, offset, buf, n); if (ret < 0) { return ret; } buf[n] = '\0'; return 0; } /** * Allocate new clusters * * @s: QED state * @n: Number of contiguous clusters to allocate * @ret: Offset of first allocated cluster * * This function only produces the offset where the new clusters should be * written. It updates BDRVQEDState but does not make any changes to the image * file. * * Called with table_lock held. */ static uint64_t qed_alloc_clusters(BDRVQEDState *s, unsigned int n) { uint64_t offset = s->file_size; s->file_size += n * s->header.cluster_size; return offset; } QEDTable *qed_alloc_table(BDRVQEDState *s) { /* Honor O_DIRECT memory alignment requirements */ return qemu_blockalign(s->bs, s->header.cluster_size * s->header.table_size); } /** * Allocate a new zeroed L2 table * * Called with table_lock held. */ static CachedL2Table *qed_new_l2_table(BDRVQEDState *s) { CachedL2Table *l2_table = qed_alloc_l2_cache_entry(&s->l2_cache); l2_table->table = qed_alloc_table(s); l2_table->offset = qed_alloc_clusters(s, s->header.table_size); memset(l2_table->table->offsets, 0, s->header.cluster_size * s->header.table_size); return l2_table; } static bool qed_plug_allocating_write_reqs(BDRVQEDState *s) { qemu_co_mutex_lock(&s->table_lock); /* No reentrancy is allowed. */ assert(!s->allocating_write_reqs_plugged); if (s->allocating_acb != NULL) { /* Another allocating write came concurrently. This cannot happen * from bdrv_qed_co_drain_begin, but it can happen when the timer runs. */ qemu_co_mutex_unlock(&s->table_lock); return false; } s->allocating_write_reqs_plugged = true; qemu_co_mutex_unlock(&s->table_lock); return true; } static void qed_unplug_allocating_write_reqs(BDRVQEDState *s) { qemu_co_mutex_lock(&s->table_lock); assert(s->allocating_write_reqs_plugged); s->allocating_write_reqs_plugged = false; qemu_co_queue_next(&s->allocating_write_reqs); qemu_co_mutex_unlock(&s->table_lock); } static void coroutine_fn qed_need_check_timer_entry(void *opaque) { BDRVQEDState *s = opaque; int ret; trace_qed_need_check_timer_cb(s); if (!qed_plug_allocating_write_reqs(s)) { return; } /* Ensure writes are on disk before clearing flag */ ret = bdrv_co_flush(s->bs->file->bs); if (ret < 0) { qed_unplug_allocating_write_reqs(s); return; } s->header.features &= ~QED_F_NEED_CHECK; ret = qed_write_header(s); (void) ret; qed_unplug_allocating_write_reqs(s); ret = bdrv_co_flush(s->bs); (void) ret; } static void qed_need_check_timer_cb(void *opaque) { Coroutine *co = qemu_coroutine_create(qed_need_check_timer_entry, opaque); qemu_coroutine_enter(co); } static void qed_start_need_check_timer(BDRVQEDState *s) { trace_qed_start_need_check_timer(s); /* Use QEMU_CLOCK_VIRTUAL so we don't alter the image file while suspended for * migration. */ timer_mod(s->need_check_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + NANOSECONDS_PER_SECOND * QED_NEED_CHECK_TIMEOUT); } /* It's okay to call this multiple times or when no timer is started */ static void qed_cancel_need_check_timer(BDRVQEDState *s) { trace_qed_cancel_need_check_timer(s); timer_del(s->need_check_timer); } static void bdrv_qed_detach_aio_context(BlockDriverState *bs) { BDRVQEDState *s = bs->opaque; qed_cancel_need_check_timer(s); timer_free(s->need_check_timer); } static void bdrv_qed_attach_aio_context(BlockDriverState *bs, AioContext *new_context) { BDRVQEDState *s = bs->opaque; s->need_check_timer = aio_timer_new(new_context, QEMU_CLOCK_VIRTUAL, SCALE_NS, qed_need_check_timer_cb, s); if (s->header.features & QED_F_NEED_CHECK) { qed_start_need_check_timer(s); } } static void coroutine_fn bdrv_qed_co_drain_begin(BlockDriverState *bs) { BDRVQEDState *s = bs->opaque; /* Fire the timer immediately in order to start doing I/O as soon as the * header is flushed. */ if (s->need_check_timer && timer_pending(s->need_check_timer)) { qed_cancel_need_check_timer(s); qed_need_check_timer_entry(s); } } static void bdrv_qed_init_state(BlockDriverState *bs) { BDRVQEDState *s = bs->opaque; memset(s, 0, sizeof(BDRVQEDState)); s->bs = bs; qemu_co_mutex_init(&s->table_lock); qemu_co_queue_init(&s->allocating_write_reqs); } /* Called with table_lock held. */ static int coroutine_fn bdrv_qed_do_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { BDRVQEDState *s = bs->opaque; QEDHeader le_header; int64_t file_size; int ret; ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header)); if (ret < 0) { return ret; } qed_header_le_to_cpu(&le_header, &s->header); if (s->header.magic != QED_MAGIC) { error_setg(errp, "Image not in QED format"); return -EINVAL; } if (s->header.features & ~QED_FEATURE_MASK) { /* image uses unsupported feature bits */ error_setg(errp, "Unsupported QED features: %" PRIx64, s->header.features & ~QED_FEATURE_MASK); return -ENOTSUP; } if (!qed_is_cluster_size_valid(s->header.cluster_size)) { return -EINVAL; } /* Round down file size to the last cluster */ file_size = bdrv_getlength(bs->file->bs); if (file_size < 0) { return file_size; } s->file_size = qed_start_of_cluster(s, file_size); if (!qed_is_table_size_valid(s->header.table_size)) { return -EINVAL; } if (!qed_is_image_size_valid(s->header.image_size, s->header.cluster_size, s->header.table_size)) { return -EINVAL; } if (!qed_check_table_offset(s, s->header.l1_table_offset)) { return -EINVAL; } s->table_nelems = (s->header.cluster_size * s->header.table_size) / sizeof(uint64_t); s->l2_shift = ctz32(s->header.cluster_size); s->l2_mask = s->table_nelems - 1; s->l1_shift = s->l2_shift + ctz32(s->table_nelems); /* Header size calculation must not overflow uint32_t */ if (s->header.header_size > UINT32_MAX / s->header.cluster_size) { return -EINVAL; } if ((s->header.features & QED_F_BACKING_FILE)) { if ((uint64_t)s->header.backing_filename_offset + s->header.backing_filename_size > s->header.cluster_size * s->header.header_size) { return -EINVAL; } ret = qed_read_string(bs->file, s->header.backing_filename_offset, s->header.backing_filename_size, bs->backing_file, sizeof(bs->backing_file)); if (ret < 0) { return ret; } if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) { pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw"); } } /* Reset unknown autoclear feature bits. This is a backwards * compatibility mechanism that allows images to be opened by older * programs, which "knock out" unknown feature bits. When an image is * opened by a newer program again it can detect that the autoclear * feature is no longer valid. */ if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 && !bdrv_is_read_only(bs->file->bs) && !(flags & BDRV_O_INACTIVE)) { s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK; ret = qed_write_header_sync(s); if (ret) { return ret; } /* From here on only known autoclear feature bits are valid */ bdrv_flush(bs->file->bs); } s->l1_table = qed_alloc_table(s); qed_init_l2_cache(&s->l2_cache); ret = qed_read_l1_table_sync(s); if (ret) { goto out; } /* If image was not closed cleanly, check consistency */ if (!(flags & BDRV_O_CHECK) && (s->header.features & QED_F_NEED_CHECK)) { /* Read-only images cannot be fixed. There is no risk of corruption * since write operations are not possible. Therefore, allow * potentially inconsistent images to be opened read-only. This can * aid data recovery from an otherwise inconsistent image. */ if (!bdrv_is_read_only(bs->file->bs) && !(flags & BDRV_O_INACTIVE)) { BdrvCheckResult result = {0}; ret = qed_check(s, &result, true); if (ret) { goto out; } } } bdrv_qed_attach_aio_context(bs, bdrv_get_aio_context(bs)); out: if (ret) { qed_free_l2_cache(&s->l2_cache); qemu_vfree(s->l1_table); } return ret; } typedef struct QEDOpenCo { BlockDriverState *bs; QDict *options; int flags; Error **errp; int ret; } QEDOpenCo; static void coroutine_fn bdrv_qed_open_entry(void *opaque) { QEDOpenCo *qoc = opaque; BDRVQEDState *s = qoc->bs->opaque; qemu_co_mutex_lock(&s->table_lock); qoc->ret = bdrv_qed_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp); qemu_co_mutex_unlock(&s->table_lock); } static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { QEDOpenCo qoc = { .bs = bs, .options = options, .flags = flags, .errp = errp, .ret = -EINPROGRESS }; bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, false, errp); if (!bs->file) { return -EINVAL; } bdrv_qed_init_state(bs); if (qemu_in_coroutine()) { bdrv_qed_open_entry(&qoc); } else { qemu_coroutine_enter(qemu_coroutine_create(bdrv_qed_open_entry, &qoc)); BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS); } BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS); return qoc.ret; } static void bdrv_qed_refresh_limits(BlockDriverState *bs, Error **errp) { BDRVQEDState *s = bs->opaque; bs->bl.pwrite_zeroes_alignment = s->header.cluster_size; } /* We have nothing to do for QED reopen, stubs just return * success */ static int bdrv_qed_reopen_prepare(BDRVReopenState *state, BlockReopenQueue *queue, Error **errp) { return 0; } static void bdrv_qed_close(BlockDriverState *bs) { BDRVQEDState *s = bs->opaque; bdrv_qed_detach_aio_context(bs); /* Ensure writes reach stable storage */ bdrv_flush(bs->file->bs); /* Clean shutdown, no check required on next open */ if (s->header.features & QED_F_NEED_CHECK) { s->header.features &= ~QED_F_NEED_CHECK; qed_write_header_sync(s); } qed_free_l2_cache(&s->l2_cache); qemu_vfree(s->l1_table); } static int coroutine_fn bdrv_qed_co_create(BlockdevCreateOptions *opts, Error **errp) { BlockdevCreateOptionsQed *qed_opts; BlockBackend *blk = NULL; BlockDriverState *bs = NULL; QEDHeader header; QEDHeader le_header; uint8_t *l1_table = NULL; size_t l1_size; int ret = 0; assert(opts->driver == BLOCKDEV_DRIVER_QED); qed_opts = &opts->u.qed; /* Validate options and set default values */ if (!qed_opts->has_cluster_size) { qed_opts->cluster_size = QED_DEFAULT_CLUSTER_SIZE; } if (!qed_opts->has_table_size) { qed_opts->table_size = QED_DEFAULT_TABLE_SIZE; } if (!qed_is_cluster_size_valid(qed_opts->cluster_size)) { error_setg(errp, "QED cluster size must be within range [%u, %u] " "and power of 2", QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE); return -EINVAL; } if (!qed_is_table_size_valid(qed_opts->table_size)) { error_setg(errp, "QED table size must be within range [%u, %u] " "and power of 2", QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE); return -EINVAL; } if (!qed_is_image_size_valid(qed_opts->size, qed_opts->cluster_size, qed_opts->table_size)) { error_setg(errp, "QED image size must be a non-zero multiple of " "cluster size and less than %" PRIu64 " bytes", qed_max_image_size(qed_opts->cluster_size, qed_opts->table_size)); return -EINVAL; } /* Create BlockBackend to write to the image */ bs = bdrv_open_blockdev_ref(qed_opts->file, errp); if (bs == NULL) { return -EIO; } blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); ret = blk_insert_bs(blk, bs, errp); if (ret < 0) { goto out; } blk_set_allow_write_beyond_eof(blk, true); /* Prepare image format */ header = (QEDHeader) { .magic = QED_MAGIC, .cluster_size = qed_opts->cluster_size, .table_size = qed_opts->table_size, .header_size = 1, .features = 0, .compat_features = 0, .l1_table_offset = qed_opts->cluster_size, .image_size = qed_opts->size, }; l1_size = header.cluster_size * header.table_size; /* File must start empty and grow, check truncate is supported */ ret = blk_truncate(blk, 0, PREALLOC_MODE_OFF, errp); if (ret < 0) { goto out; } if (qed_opts->has_backing_file) { header.features |= QED_F_BACKING_FILE; header.backing_filename_offset = sizeof(le_header); header.backing_filename_size = strlen(qed_opts->backing_file); if (qed_opts->has_backing_fmt) { const char *backing_fmt = BlockdevDriver_str(qed_opts->backing_fmt); if (qed_fmt_is_raw(backing_fmt)) { header.features |= QED_F_BACKING_FORMAT_NO_PROBE; } } } qed_header_cpu_to_le(&header, &le_header); ret = blk_pwrite(blk, 0, &le_header, sizeof(le_header), 0); if (ret < 0) { goto out; } ret = blk_pwrite(blk, sizeof(le_header), qed_opts->backing_file, header.backing_filename_size, 0); if (ret < 0) { goto out; } l1_table = g_malloc0(l1_size); ret = blk_pwrite(blk, header.l1_table_offset, l1_table, l1_size, 0); if (ret < 0) { goto out; } ret = 0; /* success */ out: g_free(l1_table); blk_unref(blk); bdrv_unref(bs); return ret; } static int coroutine_fn bdrv_qed_co_create_opts(const char *filename, QemuOpts *opts, Error **errp) { BlockdevCreateOptions *create_options = NULL; QDict *qdict; Visitor *v; BlockDriverState *bs = NULL; Error *local_err = NULL; int ret; static const QDictRenames opt_renames[] = { { BLOCK_OPT_BACKING_FILE, "backing-file" }, { BLOCK_OPT_BACKING_FMT, "backing-fmt" }, { BLOCK_OPT_CLUSTER_SIZE, "cluster-size" }, { BLOCK_OPT_TABLE_SIZE, "table-size" }, { NULL, NULL }, }; /* Parse options and convert legacy syntax */ qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qed_create_opts, true); if (!qdict_rename_keys(qdict, opt_renames, errp)) { ret = -EINVAL; goto fail; } /* Create and open the file (protocol layer) */ ret = bdrv_create_file(filename, opts, &local_err); if (ret < 0) { error_propagate(errp, local_err); goto fail; } bs = bdrv_open(filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); if (bs == NULL) { ret = -EIO; goto fail; } /* Now get the QAPI type BlockdevCreateOptions */ qdict_put_str(qdict, "driver", "qed"); qdict_put_str(qdict, "file", bs->node_name); v = qobject_input_visitor_new_flat_confused(qdict, errp); if (!v) { ret = -EINVAL; goto fail; } visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); visit_free(v); if (local_err) { error_propagate(errp, local_err); ret = -EINVAL; goto fail; } /* Silently round up size */ assert(create_options->driver == BLOCKDEV_DRIVER_QED); create_options->u.qed.size = ROUND_UP(create_options->u.qed.size, BDRV_SECTOR_SIZE); /* Create the qed image (format layer) */ ret = bdrv_qed_co_create(create_options, errp); fail: qobject_unref(qdict); bdrv_unref(bs); qapi_free_BlockdevCreateOptions(create_options); return ret; } static int coroutine_fn bdrv_qed_co_block_status(BlockDriverState *bs, bool want_zero, int64_t pos, int64_t bytes, int64_t *pnum, int64_t *map, BlockDriverState **file) { BDRVQEDState *s = bs->opaque; size_t len = MIN(bytes, SIZE_MAX); int status; QEDRequest request = { .l2_table = NULL }; uint64_t offset; int ret; qemu_co_mutex_lock(&s->table_lock); ret = qed_find_cluster(s, &request, pos, &len, &offset); *pnum = len; switch (ret) { case QED_CLUSTER_FOUND: *map = offset | qed_offset_into_cluster(s, pos); status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; *file = bs->file->bs; break; case QED_CLUSTER_ZERO: status = BDRV_BLOCK_ZERO; break; case QED_CLUSTER_L2: case QED_CLUSTER_L1: status = 0; break; default: assert(ret < 0); status = ret; break; } qed_unref_l2_cache_entry(request.l2_table); qemu_co_mutex_unlock(&s->table_lock); return status; } static BDRVQEDState *acb_to_s(QEDAIOCB *acb) { return acb->bs->opaque; } /** * Read from the backing file or zero-fill if no backing file * * @s: QED state * @pos: Byte position in device * @qiov: Destination I/O vector * @backing_qiov: Possibly shortened copy of qiov, to be allocated here * @cb: Completion function * @opaque: User data for completion function * * This function reads qiov->size bytes starting at pos from the backing file. * If there is no backing file then zeroes are read. */ static int coroutine_fn qed_read_backing_file(BDRVQEDState *s, uint64_t pos, QEMUIOVector *qiov, QEMUIOVector **backing_qiov) { uint64_t backing_length = 0; size_t size; int ret; /* If there is a backing file, get its length. Treat the absence of a * backing file like a zero length backing file. */ if (s->bs->backing) { int64_t l = bdrv_getlength(s->bs->backing->bs); if (l < 0) { return l; } backing_length = l; } /* Zero all sectors if reading beyond the end of the backing file */ if (pos >= backing_length || pos + qiov->size > backing_length) { qemu_iovec_memset(qiov, 0, 0, qiov->size); } /* Complete now if there are no backing file sectors to read */ if (pos >= backing_length) { return 0; } /* If the read straddles the end of the backing file, shorten it */ size = MIN((uint64_t)backing_length - pos, qiov->size); assert(*backing_qiov == NULL); *backing_qiov = g_new(QEMUIOVector, 1); qemu_iovec_init(*backing_qiov, qiov->niov); qemu_iovec_concat(*backing_qiov, qiov, 0, size); BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO); ret = bdrv_co_preadv(s->bs->backing, pos, size, *backing_qiov, 0); if (ret < 0) { return ret; } return 0; } /** * Copy data from backing file into the image * * @s: QED state * @pos: Byte position in device * @len: Number of bytes * @offset: Byte offset in image file */ static int coroutine_fn qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos, uint64_t len, uint64_t offset) { QEMUIOVector qiov; QEMUIOVector *backing_qiov = NULL; struct iovec iov; int ret; /* Skip copy entirely if there is no work to do */ if (len == 0) { return 0; } iov = (struct iovec) { .iov_base = qemu_blockalign(s->bs, len), .iov_len = len, }; qemu_iovec_init_external(&qiov, &iov, 1); ret = qed_read_backing_file(s, pos, &qiov, &backing_qiov); if (backing_qiov) { qemu_iovec_destroy(backing_qiov); g_free(backing_qiov); backing_qiov = NULL; } if (ret) { goto out; } BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE); ret = bdrv_co_pwritev(s->bs->file, offset, qiov.size, &qiov, 0); if (ret < 0) { goto out; } ret = 0; out: qemu_vfree(iov.iov_base); return ret; } /** * Link one or more contiguous clusters into a table * * @s: QED state * @table: L2 table * @index: First cluster index * @n: Number of contiguous clusters * @cluster: First cluster offset * * The cluster offset may be an allocated byte offset in the image file, the * zero cluster marker, or the unallocated cluster marker. * * Called with table_lock held. */ static void coroutine_fn qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index, unsigned int n, uint64_t cluster) { int i; for (i = index; i < index + n; i++) { table->offsets[i] = cluster; if (!qed_offset_is_unalloc_cluster(cluster) && !qed_offset_is_zero_cluster(cluster)) { cluster += s->header.cluster_size; } } } /* Called with table_lock held. */ static void coroutine_fn qed_aio_complete(QEDAIOCB *acb) { BDRVQEDState *s = acb_to_s(acb); /* Free resources */ qemu_iovec_destroy(&acb->cur_qiov); qed_unref_l2_cache_entry(acb->request.l2_table); /* Free the buffer we may have allocated for zero writes */ if (acb->flags & QED_AIOCB_ZERO) { qemu_vfree(acb->qiov->iov[0].iov_base); acb->qiov->iov[0].iov_base = NULL; } /* Start next allocating write request waiting behind this one. Note that * requests enqueue themselves when they first hit an unallocated cluster * but they wait until the entire request is finished before waking up the * next request in the queue. This ensures that we don't cycle through * requests multiple times but rather finish one at a time completely. */ if (acb == s->allocating_acb) { s->allocating_acb = NULL; if (!qemu_co_queue_empty(&s->allocating_write_reqs)) { qemu_co_queue_next(&s->allocating_write_reqs); } else if (s->header.features & QED_F_NEED_CHECK) { qed_start_need_check_timer(s); } } } /** * Update L1 table with new L2 table offset and write it out * * Called with table_lock held. */ static int coroutine_fn qed_aio_write_l1_update(QEDAIOCB *acb) { BDRVQEDState *s = acb_to_s(acb); CachedL2Table *l2_table = acb->request.l2_table; uint64_t l2_offset = l2_table->offset; int index, ret; index = qed_l1_index(s, acb->cur_pos); s->l1_table->offsets[index] = l2_table->offset; ret = qed_write_l1_table(s, index, 1); /* Commit the current L2 table to the cache */ qed_commit_l2_cache_entry(&s->l2_cache, l2_table); /* This is guaranteed to succeed because we just committed the entry to the * cache. */ acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset); assert(acb->request.l2_table != NULL); return ret; } /** * Update L2 table with new cluster offsets and write them out * * Called with table_lock held. */ static int coroutine_fn qed_aio_write_l2_update(QEDAIOCB *acb, uint64_t offset) { BDRVQEDState *s = acb_to_s(acb); bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1; int index, ret; if (need_alloc) { qed_unref_l2_cache_entry(acb->request.l2_table); acb->request.l2_table = qed_new_l2_table(s); } index = qed_l2_index(s, acb->cur_pos); qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters, offset); if (need_alloc) { /* Write out the whole new L2 table */ ret = qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true); if (ret) { return ret; } return qed_aio_write_l1_update(acb); } else { /* Write out only the updated part of the L2 table */ ret = qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false); if (ret) { return ret; } } return 0; } /** * Write data to the image file * * Called with table_lock *not* held. */ static int coroutine_fn qed_aio_write_main(QEDAIOCB *acb) { BDRVQEDState *s = acb_to_s(acb); uint64_t offset = acb->cur_cluster + qed_offset_into_cluster(s, acb->cur_pos); trace_qed_aio_write_main(s, acb, 0, offset, acb->cur_qiov.size); BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO); return bdrv_co_pwritev(s->bs->file, offset, acb->cur_qiov.size, &acb->cur_qiov, 0); } /** * Populate untouched regions of new data cluster * * Called with table_lock held. */ static int coroutine_fn qed_aio_write_cow(QEDAIOCB *acb) { BDRVQEDState *s = acb_to_s(acb); uint64_t start, len, offset; int ret; qemu_co_mutex_unlock(&s->table_lock); /* Populate front untouched region of new data cluster */ start = qed_start_of_cluster(s, acb->cur_pos); len = qed_offset_into_cluster(s, acb->cur_pos); trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster); ret = qed_copy_from_backing_file(s, start, len, acb->cur_cluster); if (ret < 0) { goto out; } /* Populate back untouched region of new data cluster */ start = acb->cur_pos + acb->cur_qiov.size; len = qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start; offset = acb->cur_cluster + qed_offset_into_cluster(s, acb->cur_pos) + acb->cur_qiov.size; trace_qed_aio_write_postfill(s, acb, start, len, offset); ret = qed_copy_from_backing_file(s, start, len, offset); if (ret < 0) { goto out; } ret = qed_aio_write_main(acb); if (ret < 0) { goto out; } if (s->bs->backing) { /* * Flush new data clusters before updating the L2 table * * This flush is necessary when a backing file is in use. A crash * during an allocating write could result in empty clusters in the * image. If the write only touched a subregion of the cluster, * then backing image sectors have been lost in the untouched * region. The solution is to flush after writing a new data * cluster and before updating the L2 table. */ ret = bdrv_co_flush(s->bs->file->bs); } out: qemu_co_mutex_lock(&s->table_lock); return ret; } /** * Check if the QED_F_NEED_CHECK bit should be set during allocating write */ static bool qed_should_set_need_check(BDRVQEDState *s) { /* The flush before L2 update path ensures consistency */ if (s->bs->backing) { return false; } return !(s->header.features & QED_F_NEED_CHECK); } /** * Write new data cluster * * @acb: Write request * @len: Length in bytes * * This path is taken when writing to previously unallocated clusters. * * Called with table_lock held. */ static int coroutine_fn qed_aio_write_alloc(QEDAIOCB *acb, size_t len) { BDRVQEDState *s = acb_to_s(acb); int ret; /* Cancel timer when the first allocating request comes in */ if (s->allocating_acb == NULL) { qed_cancel_need_check_timer(s); } /* Freeze this request if another allocating write is in progress */ if (s->allocating_acb != acb || s->allocating_write_reqs_plugged) { if (s->allocating_acb != NULL) { qemu_co_queue_wait(&s->allocating_write_reqs, &s->table_lock); assert(s->allocating_acb == NULL); } s->allocating_acb = acb; return -EAGAIN; /* start over with looking up table entries */ } acb->cur_nclusters = qed_bytes_to_clusters(s, qed_offset_into_cluster(s, acb->cur_pos) + len); qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); if (acb->flags & QED_AIOCB_ZERO) { /* Skip ahead if the clusters are already zero */ if (acb->find_cluster_ret == QED_CLUSTER_ZERO) { return 0; } acb->cur_cluster = 1; } else { acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters); } if (qed_should_set_need_check(s)) { s->header.features |= QED_F_NEED_CHECK; ret = qed_write_header(s); if (ret < 0) { return ret; } } if (!(acb->flags & QED_AIOCB_ZERO)) { ret = qed_aio_write_cow(acb); if (ret < 0) { return ret; } } return qed_aio_write_l2_update(acb, acb->cur_cluster); } /** * Write data cluster in place * * @acb: Write request * @offset: Cluster offset in bytes * @len: Length in bytes * * This path is taken when writing to already allocated clusters. * * Called with table_lock held. */ static int coroutine_fn qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len) { BDRVQEDState *s = acb_to_s(acb); int r; qemu_co_mutex_unlock(&s->table_lock); /* Allocate buffer for zero writes */ if (acb->flags & QED_AIOCB_ZERO) { struct iovec *iov = acb->qiov->iov; if (!iov->iov_base) { iov->iov_base = qemu_try_blockalign(acb->bs, iov->iov_len); if (iov->iov_base == NULL) { r = -ENOMEM; goto out; } memset(iov->iov_base, 0, iov->iov_len); } } /* Calculate the I/O vector */ acb->cur_cluster = offset; qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); /* Do the actual write. */ r = qed_aio_write_main(acb); out: qemu_co_mutex_lock(&s->table_lock); return r; } /** * Write data cluster * * @opaque: Write request * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2 or QED_CLUSTER_L1 * @offset: Cluster offset in bytes * @len: Length in bytes * * Called with table_lock held. */ static int coroutine_fn qed_aio_write_data(void *opaque, int ret, uint64_t offset, size_t len) { QEDAIOCB *acb = opaque; trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len); acb->find_cluster_ret = ret; switch (ret) { case QED_CLUSTER_FOUND: return qed_aio_write_inplace(acb, offset, len); case QED_CLUSTER_L2: case QED_CLUSTER_L1: case QED_CLUSTER_ZERO: return qed_aio_write_alloc(acb, len); default: g_assert_not_reached(); } } /** * Read data cluster * * @opaque: Read request * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2 or QED_CLUSTER_L1 * @offset: Cluster offset in bytes * @len: Length in bytes * * Called with table_lock held. */ static int coroutine_fn qed_aio_read_data(void *opaque, int ret, uint64_t offset, size_t len) { QEDAIOCB *acb = opaque; BDRVQEDState *s = acb_to_s(acb); BlockDriverState *bs = acb->bs; int r; qemu_co_mutex_unlock(&s->table_lock); /* Adjust offset into cluster */ offset += qed_offset_into_cluster(s, acb->cur_pos); trace_qed_aio_read_data(s, acb, ret, offset, len); qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); /* Handle zero cluster and backing file reads, otherwise read * data cluster directly. */ if (ret == QED_CLUSTER_ZERO) { qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size); r = 0; } else if (ret != QED_CLUSTER_FOUND) { r = qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov, &acb->backing_qiov); } else { BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); r = bdrv_co_preadv(bs->file, offset, acb->cur_qiov.size, &acb->cur_qiov, 0); } qemu_co_mutex_lock(&s->table_lock); return r; } /** * Begin next I/O or complete the request */ static int coroutine_fn qed_aio_next_io(QEDAIOCB *acb) { BDRVQEDState *s = acb_to_s(acb); uint64_t offset; size_t len; int ret; qemu_co_mutex_lock(&s->table_lock); while (1) { trace_qed_aio_next_io(s, acb, 0, acb->cur_pos + acb->cur_qiov.size); if (acb->backing_qiov) { qemu_iovec_destroy(acb->backing_qiov); g_free(acb->backing_qiov); acb->backing_qiov = NULL; } acb->qiov_offset += acb->cur_qiov.size; acb->cur_pos += acb->cur_qiov.size; qemu_iovec_reset(&acb->cur_qiov); /* Complete request */ if (acb->cur_pos >= acb->end_pos) { ret = 0; break; } /* Find next cluster and start I/O */ len = acb->end_pos - acb->cur_pos; ret = qed_find_cluster(s, &acb->request, acb->cur_pos, &len, &offset); if (ret < 0) { break; } if (acb->flags & QED_AIOCB_WRITE) { ret = qed_aio_write_data(acb, ret, offset, len); } else { ret = qed_aio_read_data(acb, ret, offset, len); } if (ret < 0 && ret != -EAGAIN) { break; } } trace_qed_aio_complete(s, acb, ret); qed_aio_complete(acb); qemu_co_mutex_unlock(&s->table_lock); return ret; } static int coroutine_fn qed_co_request(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, int flags) { QEDAIOCB acb = { .bs = bs, .cur_pos = (uint64_t) sector_num * BDRV_SECTOR_SIZE, .end_pos = (sector_num + nb_sectors) * BDRV_SECTOR_SIZE, .qiov = qiov, .flags = flags, }; qemu_iovec_init(&acb.cur_qiov, qiov->niov); trace_qed_aio_setup(bs->opaque, &acb, sector_num, nb_sectors, NULL, flags); /* Start request */ return qed_aio_next_io(&acb); } static int coroutine_fn bdrv_qed_co_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) { return qed_co_request(bs, sector_num, qiov, nb_sectors, 0); } static int coroutine_fn bdrv_qed_co_writev(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags) { assert(!flags); return qed_co_request(bs, sector_num, qiov, nb_sectors, QED_AIOCB_WRITE); } static int coroutine_fn bdrv_qed_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int bytes, BdrvRequestFlags flags) { BDRVQEDState *s = bs->opaque; QEMUIOVector qiov; struct iovec iov; /* Fall back if the request is not aligned */ if (qed_offset_into_cluster(s, offset) || qed_offset_into_cluster(s, bytes)) { return -ENOTSUP; } /* Zero writes start without an I/O buffer. If a buffer becomes necessary * then it will be allocated during request processing. */ iov.iov_base = NULL; iov.iov_len = bytes; qemu_iovec_init_external(&qiov, &iov, 1); return qed_co_request(bs, offset >> BDRV_SECTOR_BITS, &qiov, bytes >> BDRV_SECTOR_BITS, QED_AIOCB_WRITE | QED_AIOCB_ZERO); } static int coroutine_fn bdrv_qed_co_truncate(BlockDriverState *bs, int64_t offset, PreallocMode prealloc, Error **errp) { BDRVQEDState *s = bs->opaque; uint64_t old_image_size; int ret; if (prealloc != PREALLOC_MODE_OFF) { error_setg(errp, "Unsupported preallocation mode '%s'", PreallocMode_str(prealloc)); return -ENOTSUP; } if (!qed_is_image_size_valid(offset, s->header.cluster_size, s->header.table_size)) { error_setg(errp, "Invalid image size specified"); return -EINVAL; } if ((uint64_t)offset < s->header.image_size) { error_setg(errp, "Shrinking images is currently not supported"); return -ENOTSUP; } old_image_size = s->header.image_size; s->header.image_size = offset; ret = qed_write_header_sync(s); if (ret < 0) { s->header.image_size = old_image_size; error_setg_errno(errp, -ret, "Failed to update the image size"); } return ret; } static int64_t bdrv_qed_getlength(BlockDriverState *bs) { BDRVQEDState *s = bs->opaque; return s->header.image_size; } static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BDRVQEDState *s = bs->opaque; memset(bdi, 0, sizeof(*bdi)); bdi->cluster_size = s->header.cluster_size; bdi->is_dirty = s->header.features & QED_F_NEED_CHECK; bdi->unallocated_blocks_are_zero = true; return 0; } static int bdrv_qed_change_backing_file(BlockDriverState *bs, const char *backing_file, const char *backing_fmt) { BDRVQEDState *s = bs->opaque; QEDHeader new_header, le_header; void *buffer; size_t buffer_len, backing_file_len; int ret; /* Refuse to set backing filename if unknown compat feature bits are * active. If the image uses an unknown compat feature then we may not * know the layout of data following the header structure and cannot safely * add a new string. */ if (backing_file && (s->header.compat_features & ~QED_COMPAT_FEATURE_MASK)) { return -ENOTSUP; } memcpy(&new_header, &s->header, sizeof(new_header)); new_header.features &= ~(QED_F_BACKING_FILE | QED_F_BACKING_FORMAT_NO_PROBE); /* Adjust feature flags */ if (backing_file) { new_header.features |= QED_F_BACKING_FILE; if (qed_fmt_is_raw(backing_fmt)) { new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE; } } /* Calculate new header size */ backing_file_len = 0; if (backing_file) { backing_file_len = strlen(backing_file); } buffer_len = sizeof(new_header); new_header.backing_filename_offset = buffer_len; new_header.backing_filename_size = backing_file_len; buffer_len += backing_file_len; /* Make sure we can rewrite header without failing */ if (buffer_len > new_header.header_size * new_header.cluster_size) { return -ENOSPC; } /* Prepare new header */ buffer = g_malloc(buffer_len); qed_header_cpu_to_le(&new_header, &le_header); memcpy(buffer, &le_header, sizeof(le_header)); buffer_len = sizeof(le_header); if (backing_file) { memcpy(buffer + buffer_len, backing_file, backing_file_len); buffer_len += backing_file_len; } /* Write new header */ ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len); g_free(buffer); if (ret == 0) { memcpy(&s->header, &new_header, sizeof(new_header)); } return ret; } static void coroutine_fn bdrv_qed_co_invalidate_cache(BlockDriverState *bs, Error **errp) { BDRVQEDState *s = bs->opaque; Error *local_err = NULL; int ret; bdrv_qed_close(bs); bdrv_qed_init_state(bs); qemu_co_mutex_lock(&s->table_lock); ret = bdrv_qed_do_open(bs, NULL, bs->open_flags, &local_err); qemu_co_mutex_unlock(&s->table_lock); if (local_err) { error_propagate_prepend(errp, local_err, "Could not reopen qed layer: "); return; } else if (ret < 0) { error_setg_errno(errp, -ret, "Could not reopen qed layer"); return; } } static int bdrv_qed_co_check(BlockDriverState *bs, BdrvCheckResult *result, BdrvCheckMode fix) { BDRVQEDState *s = bs->opaque; int ret; qemu_co_mutex_lock(&s->table_lock); ret = qed_check(s, result, !!fix); qemu_co_mutex_unlock(&s->table_lock); return ret; } static QemuOptsList qed_create_opts = { .name = "qed-create-opts", .head = QTAILQ_HEAD_INITIALIZER(qed_create_opts.head), .desc = { { .name = BLOCK_OPT_SIZE, .type = QEMU_OPT_SIZE, .help = "Virtual disk size" }, { .name = BLOCK_OPT_BACKING_FILE, .type = QEMU_OPT_STRING, .help = "File name of a base image" }, { .name = BLOCK_OPT_BACKING_FMT, .type = QEMU_OPT_STRING, .help = "Image format of the base image" }, { .name = BLOCK_OPT_CLUSTER_SIZE, .type = QEMU_OPT_SIZE, .help = "Cluster size (in bytes)", .def_value_str = stringify(QED_DEFAULT_CLUSTER_SIZE) }, { .name = BLOCK_OPT_TABLE_SIZE, .type = QEMU_OPT_SIZE, .help = "L1/L2 table size (in clusters)" }, { /* end of list */ } } }; static BlockDriver bdrv_qed = { .format_name = "qed", .instance_size = sizeof(BDRVQEDState), .create_opts = &qed_create_opts, .supports_backing = true, .bdrv_probe = bdrv_qed_probe, .bdrv_open = bdrv_qed_open, .bdrv_close = bdrv_qed_close, .bdrv_reopen_prepare = bdrv_qed_reopen_prepare, .bdrv_child_perm = bdrv_format_default_perms, .bdrv_co_create = bdrv_qed_co_create, .bdrv_co_create_opts = bdrv_qed_co_create_opts, .bdrv_has_zero_init = bdrv_has_zero_init_1, .bdrv_co_block_status = bdrv_qed_co_block_status, .bdrv_co_readv = bdrv_qed_co_readv, .bdrv_co_writev = bdrv_qed_co_writev, .bdrv_co_pwrite_zeroes = bdrv_qed_co_pwrite_zeroes, .bdrv_co_truncate = bdrv_qed_co_truncate, .bdrv_getlength = bdrv_qed_getlength, .bdrv_get_info = bdrv_qed_get_info, .bdrv_refresh_limits = bdrv_qed_refresh_limits, .bdrv_change_backing_file = bdrv_qed_change_backing_file, .bdrv_co_invalidate_cache = bdrv_qed_co_invalidate_cache, .bdrv_co_check = bdrv_qed_co_check, .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, .bdrv_co_drain_begin = bdrv_qed_co_drain_begin, }; static void bdrv_qed_init(void) { bdrv_register(&bdrv_qed); } block_init(bdrv_qed_init);