| /* |
| * 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 "qapi/error.h" |
| #include "qemu/timer.h" |
| #include "qemu/bswap.h" |
| #include "trace.h" |
| #include "qed.h" |
| #include "qapi/qmp/qerror.h" |
| #include "sysemu/block-backend.h" |
| |
| 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. |
| */ |
| 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; |
| |
| 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. |
| */ |
| 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 |
| */ |
| 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 void qed_plug_allocating_write_reqs(BDRVQEDState *s) |
| { |
| assert(!s->allocating_write_reqs_plugged); |
| |
| s->allocating_write_reqs_plugged = true; |
| } |
| |
| static void qed_unplug_allocating_write_reqs(BDRVQEDState *s) |
| { |
| assert(s->allocating_write_reqs_plugged); |
| |
| s->allocating_write_reqs_plugged = false; |
| qemu_co_enter_next(&s->allocating_write_reqs); |
| } |
| |
| static void coroutine_fn qed_need_check_timer_entry(void *opaque) |
| { |
| BDRVQEDState *s = opaque; |
| int ret; |
| |
| /* The timer should only fire when allocating writes have drained */ |
| assert(!s->allocating_acb); |
| |
| trace_qed_need_check_timer_cb(s); |
| |
| qed_acquire(s); |
| qed_plug_allocating_write_reqs(s); |
| |
| /* Ensure writes are on disk before clearing flag */ |
| ret = bdrv_co_flush(s->bs->file->bs); |
| qed_release(s); |
| 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); |
| } |
| |
| void qed_acquire(BDRVQEDState *s) |
| { |
| aio_context_acquire(bdrv_get_aio_context(s->bs)); |
| } |
| |
| void qed_release(BDRVQEDState *s) |
| { |
| aio_context_release(bdrv_get_aio_context(s->bs)); |
| } |
| |
| 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 bdrv_qed_drain(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_cb(s); |
| } |
| } |
| |
| static int 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; |
| |
| s->bs = bs; |
| qemu_co_queue_init(&s->allocating_write_reqs); |
| |
| 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; |
| } |
| |
| static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags, |
| Error **errp) |
| { |
| bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, |
| false, errp); |
| if (!bs->file) { |
| return -EINVAL; |
| } |
| |
| return bdrv_qed_do_open(bs, options, flags, errp); |
| } |
| |
| 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 qed_create(const char *filename, uint32_t cluster_size, |
| uint64_t image_size, uint32_t table_size, |
| const char *backing_file, const char *backing_fmt, |
| QemuOpts *opts, Error **errp) |
| { |
| QEDHeader header = { |
| .magic = QED_MAGIC, |
| .cluster_size = cluster_size, |
| .table_size = table_size, |
| .header_size = 1, |
| .features = 0, |
| .compat_features = 0, |
| .l1_table_offset = cluster_size, |
| .image_size = image_size, |
| }; |
| QEDHeader le_header; |
| uint8_t *l1_table = NULL; |
| size_t l1_size = header.cluster_size * header.table_size; |
| Error *local_err = NULL; |
| int ret = 0; |
| BlockBackend *blk; |
| |
| ret = bdrv_create_file(filename, opts, &local_err); |
| if (ret < 0) { |
| error_propagate(errp, local_err); |
| return ret; |
| } |
| |
| blk = blk_new_open(filename, NULL, NULL, |
| BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, |
| &local_err); |
| if (blk == NULL) { |
| error_propagate(errp, local_err); |
| return -EIO; |
| } |
| |
| blk_set_allow_write_beyond_eof(blk, true); |
| |
| /* 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 (backing_file) { |
| header.features |= QED_F_BACKING_FILE; |
| header.backing_filename_offset = sizeof(le_header); |
| header.backing_filename_size = strlen(backing_file); |
| |
| 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), 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); |
| return ret; |
| } |
| |
| static int bdrv_qed_create(const char *filename, QemuOpts *opts, Error **errp) |
| { |
| uint64_t image_size = 0; |
| uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE; |
| uint32_t table_size = QED_DEFAULT_TABLE_SIZE; |
| char *backing_file = NULL; |
| char *backing_fmt = NULL; |
| int ret; |
| |
| image_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), |
| BDRV_SECTOR_SIZE); |
| backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); |
| backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); |
| cluster_size = qemu_opt_get_size_del(opts, |
| BLOCK_OPT_CLUSTER_SIZE, |
| QED_DEFAULT_CLUSTER_SIZE); |
| table_size = qemu_opt_get_size_del(opts, BLOCK_OPT_TABLE_SIZE, |
| QED_DEFAULT_TABLE_SIZE); |
| |
| if (!qed_is_cluster_size_valid(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); |
| ret = -EINVAL; |
| goto finish; |
| } |
| if (!qed_is_table_size_valid(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); |
| ret = -EINVAL; |
| goto finish; |
| } |
| if (!qed_is_image_size_valid(image_size, cluster_size, 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(cluster_size, table_size)); |
| ret = -EINVAL; |
| goto finish; |
| } |
| |
| ret = qed_create(filename, cluster_size, image_size, table_size, |
| backing_file, backing_fmt, opts, errp); |
| |
| finish: |
| g_free(backing_file); |
| g_free(backing_fmt); |
| return ret; |
| } |
| |
| typedef struct { |
| BlockDriverState *bs; |
| Coroutine *co; |
| uint64_t pos; |
| int64_t status; |
| int *pnum; |
| BlockDriverState **file; |
| } QEDIsAllocatedCB; |
| |
| static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len) |
| { |
| QEDIsAllocatedCB *cb = opaque; |
| BDRVQEDState *s = cb->bs->opaque; |
| *cb->pnum = len / BDRV_SECTOR_SIZE; |
| switch (ret) { |
| case QED_CLUSTER_FOUND: |
| offset |= qed_offset_into_cluster(s, cb->pos); |
| cb->status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | offset; |
| *cb->file = cb->bs->file->bs; |
| break; |
| case QED_CLUSTER_ZERO: |
| cb->status = BDRV_BLOCK_ZERO; |
| break; |
| case QED_CLUSTER_L2: |
| case QED_CLUSTER_L1: |
| cb->status = 0; |
| break; |
| default: |
| assert(ret < 0); |
| cb->status = ret; |
| break; |
| } |
| |
| if (cb->co) { |
| aio_co_wake(cb->co); |
| } |
| } |
| |
| static int64_t coroutine_fn bdrv_qed_co_get_block_status(BlockDriverState *bs, |
| int64_t sector_num, |
| int nb_sectors, int *pnum, |
| BlockDriverState **file) |
| { |
| BDRVQEDState *s = bs->opaque; |
| size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE; |
| QEDIsAllocatedCB cb = { |
| .bs = bs, |
| .pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE, |
| .status = BDRV_BLOCK_OFFSET_MASK, |
| .pnum = pnum, |
| .file = file, |
| }; |
| QEDRequest request = { .l2_table = NULL }; |
| uint64_t offset; |
| int ret; |
| |
| ret = qed_find_cluster(s, &request, cb.pos, &len, &offset); |
| qed_is_allocated_cb(&cb, ret, offset, len); |
| |
| /* The callback was invoked immediately */ |
| assert(cb.status != BDRV_BLOCK_OFFSET_MASK); |
| |
| qed_unref_l2_cache_entry(request.l2_table); |
| |
| return cb.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. |
| */ |
| 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; |
| } |
| } |
| } |
| |
| 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_enter_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 |
| */ |
| 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 |
| */ |
| 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 |
| */ |
| 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); |
| int ret; |
| |
| trace_qed_aio_write_main(s, acb, 0, offset, acb->cur_qiov.size); |
| |
| BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO); |
| ret = bdrv_co_pwritev(s->bs->file, offset, acb->cur_qiov.size, |
| &acb->cur_qiov, 0); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| if (acb->find_cluster_ret != QED_CLUSTER_FOUND) { |
| 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); |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| ret = qed_aio_write_l2_update(acb, acb->cur_cluster); |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| return 0; |
| } |
| |
| /** |
| * Populate untouched regions of new data cluster |
| */ |
| static int coroutine_fn qed_aio_write_cow(QEDAIOCB *acb) |
| { |
| BDRVQEDState *s = acb_to_s(acb); |
| uint64_t start, len, offset; |
| int ret; |
| |
| /* 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) { |
| return ret; |
| } |
| |
| /* 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) { |
| return ret; |
| } |
| |
| return qed_aio_write_main(acb); |
| } |
| |
| /** |
| * 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. |
| */ |
| 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, NULL); |
| 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; |
| } |
| } 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_l2_update(acb, 1); |
| } else { |
| ret = qed_aio_write_cow(acb); |
| } |
| if (ret < 0) { |
| return ret; |
| } |
| return 0; |
| } |
| |
| /** |
| * 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. |
| */ |
| static int coroutine_fn qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, |
| size_t len) |
| { |
| /* 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) { |
| return -ENOMEM; |
| } |
| 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 */ |
| return qed_aio_write_main(acb); |
| } |
| |
| /** |
| * 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 |
| */ |
| 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 |
| */ |
| 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; |
| |
| /* 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 */ |
| if (ret == QED_CLUSTER_ZERO) { |
| qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size); |
| return 0; |
| } else if (ret != QED_CLUSTER_FOUND) { |
| return qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov, |
| &acb->backing_qiov); |
| } |
| |
| BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); |
| ret = bdrv_co_preadv(bs->file, offset, acb->cur_qiov.size, |
| &acb->cur_qiov, 0); |
| if (ret < 0) { |
| return ret; |
| } |
| return 0; |
| } |
| |
| /** |
| * 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; |
| |
| 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); |
| 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) |
| { |
| 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 bdrv_qed_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_lookup[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; |
| bdi->can_write_zeroes_with_unmap = 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 bdrv_qed_invalidate_cache(BlockDriverState *bs, Error **errp) |
| { |
| BDRVQEDState *s = bs->opaque; |
| Error *local_err = NULL; |
| int ret; |
| |
| bdrv_qed_close(bs); |
| |
| memset(s, 0, sizeof(BDRVQEDState)); |
| ret = bdrv_qed_do_open(bs, NULL, bs->open_flags, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| error_prepend(errp, "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_check(BlockDriverState *bs, BdrvCheckResult *result, |
| BdrvCheckMode fix) |
| { |
| BDRVQEDState *s = bs->opaque; |
| |
| return qed_check(s, result, !!fix); |
| } |
| |
| 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_create = bdrv_qed_create, |
| .bdrv_has_zero_init = bdrv_has_zero_init_1, |
| .bdrv_co_get_block_status = bdrv_qed_co_get_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_truncate = bdrv_qed_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_invalidate_cache = bdrv_qed_invalidate_cache, |
| .bdrv_check = bdrv_qed_check, |
| .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, |
| .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, |
| .bdrv_drain = bdrv_qed_drain, |
| }; |
| |
| static void bdrv_qed_init(void) |
| { |
| bdrv_register(&bdrv_qed); |
| } |
| |
| block_init(bdrv_qed_init); |