--- /dev/null
+/*
+ * Block driver for the QCOW version 2 format
+ *
+ * Copyright (c) 2004-2006 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu-common.h"
+#include "block/block_int.h"
+#include "qemu/module.h"
+#include <zlib.h>
+#include "block/qcow2.h"
+#include "qemu/error-report.h"
+#include "qapi/qmp/qerror.h"
+#include "qapi/qmp/qbool.h"
+#include "qapi/util.h"
+#include "qapi/qmp/types.h"
+#include "qapi-event.h"
+#include "trace.h"
+#include "qemu/option_int.h"
+
+/*
+ Differences with QCOW:
+
+ - Support for multiple incremental snapshots.
+ - Memory management by reference counts.
+ - Clusters which have a reference count of one have the bit
+ QCOW_OFLAG_COPIED to optimize write performance.
+ - Size of compressed clusters is stored in sectors to reduce bit usage
+ in the cluster offsets.
+ - Support for storing additional data (such as the VM state) in the
+ snapshots.
+ - If a backing store is used, the cluster size is not constrained
+ (could be backported to QCOW).
+ - L2 tables have always a size of one cluster.
+*/
+
+
+typedef struct {
+ uint32_t magic;
+ uint32_t len;
+} QEMU_PACKED QCowExtension;
+
+#define QCOW2_EXT_MAGIC_END 0
+#define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
+#define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
+
+static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename)
+{
+ const QCowHeader *cow_header = (const void *)buf;
+
+ if (buf_size >= sizeof(QCowHeader) &&
+ be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
+ be32_to_cpu(cow_header->version) >= 2)
+ return 100;
+ else
+ return 0;
+}
+
+
+/*
+ * read qcow2 extension and fill bs
+ * start reading from start_offset
+ * finish reading upon magic of value 0 or when end_offset reached
+ * unknown magic is skipped (future extension this version knows nothing about)
+ * return 0 upon success, non-0 otherwise
+ */
+static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
+ uint64_t end_offset, void **p_feature_table,
+ Error **errp)
+{
+ BDRVQcowState *s = bs->opaque;
+ QCowExtension ext;
+ uint64_t offset;
+ int ret;
+
+#ifdef DEBUG_EXT
+ printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
+#endif
+ offset = start_offset;
+ while (offset < end_offset) {
+
+#ifdef DEBUG_EXT
+ /* Sanity check */
+ if (offset > s->cluster_size)
+ printf("qcow2_read_extension: suspicious offset %lu\n", offset);
+
+ printf("attempting to read extended header in offset %lu\n", offset);
+#endif
+
+ ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext));
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: "
+ "pread fail from offset %" PRIu64, offset);
+ return 1;
+ }
+ be32_to_cpus(&ext.magic);
+ be32_to_cpus(&ext.len);
+ offset += sizeof(ext);
+#ifdef DEBUG_EXT
+ printf("ext.magic = 0x%x\n", ext.magic);
+#endif
+ if (offset > end_offset || ext.len > end_offset - offset) {
+ error_setg(errp, "Header extension too large");
+ return -EINVAL;
+ }
+
+ switch (ext.magic) {
+ case QCOW2_EXT_MAGIC_END:
+ return 0;
+
+ case QCOW2_EXT_MAGIC_BACKING_FORMAT:
+ if (ext.len >= sizeof(bs->backing_format)) {
+ error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32
+ " too large (>=%zu)", ext.len,
+ sizeof(bs->backing_format));
+ return 2;
+ }
+ ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "ERROR: ext_backing_format: "
+ "Could not read format name");
+ return 3;
+ }
+ bs->backing_format[ext.len] = '\0';
+ s->image_backing_format = g_strdup(bs->backing_format);
+#ifdef DEBUG_EXT
+ printf("Qcow2: Got format extension %s\n", bs->backing_format);
+#endif
+ break;
+
+ case QCOW2_EXT_MAGIC_FEATURE_TABLE:
+ if (p_feature_table != NULL) {
+ void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature));
+ ret = bdrv_pread(bs->file, offset , feature_table, ext.len);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "ERROR: ext_feature_table: "
+ "Could not read table");
+ return ret;
+ }
+
+ *p_feature_table = feature_table;
+ }
+ break;
+
+ default:
+ /* unknown magic - save it in case we need to rewrite the header */
+ {
+ Qcow2UnknownHeaderExtension *uext;
+
+ uext = g_malloc0(sizeof(*uext) + ext.len);
+ uext->magic = ext.magic;
+ uext->len = ext.len;
+ QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next);
+
+ ret = bdrv_pread(bs->file, offset , uext->data, uext->len);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "ERROR: unknown extension: "
+ "Could not read data");
+ return ret;
+ }
+ }
+ break;
+ }
+
+ offset += ((ext.len + 7) & ~7);
+ }
+
+ return 0;
+}
+
+static void cleanup_unknown_header_ext(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ Qcow2UnknownHeaderExtension *uext, *next;
+
+ QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) {
+ QLIST_REMOVE(uext, next);
+ g_free(uext);
+ }
+}
+
+static void GCC_FMT_ATTR(3, 4) report_unsupported(BlockDriverState *bs,
+ Error **errp, const char *fmt, ...)
+{
+ char msg[64];
+ va_list ap;
+
+ va_start(ap, fmt);
+ vsnprintf(msg, sizeof(msg), fmt, ap);
+ va_end(ap);
+
+ error_setg(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
+ bdrv_get_device_or_node_name(bs), "qcow2", msg);
+}
+
+static void report_unsupported_feature(BlockDriverState *bs,
+ Error **errp, Qcow2Feature *table, uint64_t mask)
+{
+ char *features = g_strdup("");
+ char *old;
+
+ while (table && table->name[0] != '\0') {
+ if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) {
+ if (mask & (1ULL << table->bit)) {
+ old = features;
+ features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "",
+ table->name);
+ g_free(old);
+ mask &= ~(1ULL << table->bit);
+ }
+ }
+ table++;
+ }
+
+ if (mask) {
+ old = features;
+ features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64,
+ old, *old ? ", " : "", mask);
+ g_free(old);
+ }
+
+ report_unsupported(bs, errp, "%s", features);
+ g_free(features);
+}
+
+/*
+ * Sets the dirty bit and flushes afterwards if necessary.
+ *
+ * The incompatible_features bit is only set if the image file header was
+ * updated successfully. Therefore it is not required to check the return
+ * value of this function.
+ */
+int qcow2_mark_dirty(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t val;
+ int ret;
+
+ assert(s->qcow_version >= 3);
+
+ if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
+ return 0; /* already dirty */
+ }
+
+ val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY);
+ ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features),
+ &val, sizeof(val));
+ if (ret < 0) {
+ return ret;
+ }
+ ret = bdrv_flush(bs->file);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* Only treat image as dirty if the header was updated successfully */
+ s->incompatible_features |= QCOW2_INCOMPAT_DIRTY;
+ return 0;
+}
+
+/*
+ * Clears the dirty bit and flushes before if necessary. Only call this
+ * function when there are no pending requests, it does not guard against
+ * concurrent requests dirtying the image.
+ */
+static int qcow2_mark_clean(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+
+ if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
+ int ret;
+
+ s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY;
+
+ ret = bdrv_flush(bs);
+ if (ret < 0) {
+ return ret;
+ }
+
+ return qcow2_update_header(bs);
+ }
+ return 0;
+}
+
+/*
+ * Marks the image as corrupt.
+ */
+int qcow2_mark_corrupt(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+
+ s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT;
+ return qcow2_update_header(bs);
+}
+
+/*
+ * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes
+ * before if necessary.
+ */
+int qcow2_mark_consistent(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+
+ if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
+ int ret = bdrv_flush(bs);
+ if (ret < 0) {
+ return ret;
+ }
+
+ s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT;
+ return qcow2_update_header(bs);
+ }
+ return 0;
+}
+
+static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result,
+ BdrvCheckMode fix)
+{
+ int ret = qcow2_check_refcounts(bs, result, fix);
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (fix && result->check_errors == 0 && result->corruptions == 0) {
+ ret = qcow2_mark_clean(bs);
+ if (ret < 0) {
+ return ret;
+ }
+ return qcow2_mark_consistent(bs);
+ }
+ return ret;
+}
+
+static int validate_table_offset(BlockDriverState *bs, uint64_t offset,
+ uint64_t entries, size_t entry_len)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t size;
+
+ /* Use signed INT64_MAX as the maximum even for uint64_t header fields,
+ * because values will be passed to qemu functions taking int64_t. */
+ if (entries > INT64_MAX / entry_len) {
+ return -EINVAL;
+ }
+
+ size = entries * entry_len;
+
+ if (INT64_MAX - size < offset) {
+ return -EINVAL;
+ }
+
+ /* Tables must be cluster aligned */
+ if (offset & (s->cluster_size - 1)) {
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static QemuOptsList qcow2_runtime_opts = {
+ .name = "qcow2",
+ .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head),
+ .desc = {
+ {
+ .name = QCOW2_OPT_LAZY_REFCOUNTS,
+ .type = QEMU_OPT_BOOL,
+ .help = "Postpone refcount updates",
+ },
+ {
+ .name = QCOW2_OPT_DISCARD_REQUEST,
+ .type = QEMU_OPT_BOOL,
+ .help = "Pass guest discard requests to the layer below",
+ },
+ {
+ .name = QCOW2_OPT_DISCARD_SNAPSHOT,
+ .type = QEMU_OPT_BOOL,
+ .help = "Generate discard requests when snapshot related space "
+ "is freed",
+ },
+ {
+ .name = QCOW2_OPT_DISCARD_OTHER,
+ .type = QEMU_OPT_BOOL,
+ .help = "Generate discard requests when other clusters are freed",
+ },
+ {
+ .name = QCOW2_OPT_OVERLAP,
+ .type = QEMU_OPT_STRING,
+ .help = "Selects which overlap checks to perform from a range of "
+ "templates (none, constant, cached, all)",
+ },
+ {
+ .name = QCOW2_OPT_OVERLAP_TEMPLATE,
+ .type = QEMU_OPT_STRING,
+ .help = "Selects which overlap checks to perform from a range of "
+ "templates (none, constant, cached, all)",
+ },
+ {
+ .name = QCOW2_OPT_OVERLAP_MAIN_HEADER,
+ .type = QEMU_OPT_BOOL,
+ .help = "Check for unintended writes into the main qcow2 header",
+ },
+ {
+ .name = QCOW2_OPT_OVERLAP_ACTIVE_L1,
+ .type = QEMU_OPT_BOOL,
+ .help = "Check for unintended writes into the active L1 table",
+ },
+ {
+ .name = QCOW2_OPT_OVERLAP_ACTIVE_L2,
+ .type = QEMU_OPT_BOOL,
+ .help = "Check for unintended writes into an active L2 table",
+ },
+ {
+ .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
+ .type = QEMU_OPT_BOOL,
+ .help = "Check for unintended writes into the refcount table",
+ },
+ {
+ .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
+ .type = QEMU_OPT_BOOL,
+ .help = "Check for unintended writes into a refcount block",
+ },
+ {
+ .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
+ .type = QEMU_OPT_BOOL,
+ .help = "Check for unintended writes into the snapshot table",
+ },
+ {
+ .name = QCOW2_OPT_OVERLAP_INACTIVE_L1,
+ .type = QEMU_OPT_BOOL,
+ .help = "Check for unintended writes into an inactive L1 table",
+ },
+ {
+ .name = QCOW2_OPT_OVERLAP_INACTIVE_L2,
+ .type = QEMU_OPT_BOOL,
+ .help = "Check for unintended writes into an inactive L2 table",
+ },
+ {
+ .name = QCOW2_OPT_CACHE_SIZE,
+ .type = QEMU_OPT_SIZE,
+ .help = "Maximum combined metadata (L2 tables and refcount blocks) "
+ "cache size",
+ },
+ {
+ .name = QCOW2_OPT_L2_CACHE_SIZE,
+ .type = QEMU_OPT_SIZE,
+ .help = "Maximum L2 table cache size",
+ },
+ {
+ .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE,
+ .type = QEMU_OPT_SIZE,
+ .help = "Maximum refcount block cache size",
+ },
+ { /* end of list */ }
+ },
+};
+
+static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = {
+ [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER,
+ [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1,
+ [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2,
+ [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
+ [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
+ [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
+ [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1,
+ [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2,
+};
+
+static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts,
+ uint64_t *l2_cache_size,
+ uint64_t *refcount_cache_size, Error **errp)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t combined_cache_size;
+ bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set;
+
+ combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE);
+ l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE);
+ refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
+
+ combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0);
+ *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0);
+ *refcount_cache_size = qemu_opt_get_size(opts,
+ QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0);
+
+ if (combined_cache_size_set) {
+ if (l2_cache_size_set && refcount_cache_size_set) {
+ error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE
+ " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set "
+ "the same time");
+ return;
+ } else if (*l2_cache_size > combined_cache_size) {
+ error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed "
+ QCOW2_OPT_CACHE_SIZE);
+ return;
+ } else if (*refcount_cache_size > combined_cache_size) {
+ error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed "
+ QCOW2_OPT_CACHE_SIZE);
+ return;
+ }
+
+ if (l2_cache_size_set) {
+ *refcount_cache_size = combined_cache_size - *l2_cache_size;
+ } else if (refcount_cache_size_set) {
+ *l2_cache_size = combined_cache_size - *refcount_cache_size;
+ } else {
+ *refcount_cache_size = combined_cache_size
+ / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1);
+ *l2_cache_size = combined_cache_size - *refcount_cache_size;
+ }
+ } else {
+ if (!l2_cache_size_set && !refcount_cache_size_set) {
+ *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE,
+ (uint64_t)DEFAULT_L2_CACHE_CLUSTERS
+ * s->cluster_size);
+ *refcount_cache_size = *l2_cache_size
+ / DEFAULT_L2_REFCOUNT_SIZE_RATIO;
+ } else if (!l2_cache_size_set) {
+ *l2_cache_size = *refcount_cache_size
+ * DEFAULT_L2_REFCOUNT_SIZE_RATIO;
+ } else if (!refcount_cache_size_set) {
+ *refcount_cache_size = *l2_cache_size
+ / DEFAULT_L2_REFCOUNT_SIZE_RATIO;
+ }
+ }
+}
+
+static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
+{
+ BDRVQcowState *s = bs->opaque;
+ unsigned int len, i;
+ int ret = 0;
+ QCowHeader header;
+ QemuOpts *opts = NULL;
+ Error *local_err = NULL;
+ uint64_t ext_end;
+ uint64_t l1_vm_state_index;
+ const char *opt_overlap_check, *opt_overlap_check_template;
+ int overlap_check_template = 0;
+ uint64_t l2_cache_size, refcount_cache_size;
+
+ ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not read qcow2 header");
+ goto fail;
+ }
+ be32_to_cpus(&header.magic);
+ be32_to_cpus(&header.version);
+ be64_to_cpus(&header.backing_file_offset);
+ be32_to_cpus(&header.backing_file_size);
+ be64_to_cpus(&header.size);
+ be32_to_cpus(&header.cluster_bits);
+ be32_to_cpus(&header.crypt_method);
+ be64_to_cpus(&header.l1_table_offset);
+ be32_to_cpus(&header.l1_size);
+ be64_to_cpus(&header.refcount_table_offset);
+ be32_to_cpus(&header.refcount_table_clusters);
+ be64_to_cpus(&header.snapshots_offset);
+ be32_to_cpus(&header.nb_snapshots);
+
+ if (header.magic != QCOW_MAGIC) {
+ error_setg(errp, "Image is not in qcow2 format");
+ ret = -EINVAL;
+ goto fail;
+ }
+ if (header.version < 2 || header.version > 3) {
+ report_unsupported(bs, errp, "QCOW version %" PRIu32, header.version);
+ ret = -ENOTSUP;
+ goto fail;
+ }
+
+ s->qcow_version = header.version;
+
+ /* Initialise cluster size */
+ if (header.cluster_bits < MIN_CLUSTER_BITS ||
+ header.cluster_bits > MAX_CLUSTER_BITS) {
+ error_setg(errp, "Unsupported cluster size: 2^%" PRIu32,
+ header.cluster_bits);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ s->cluster_bits = header.cluster_bits;
+ s->cluster_size = 1 << s->cluster_bits;
+ s->cluster_sectors = 1 << (s->cluster_bits - 9);
+
+ /* Initialise version 3 header fields */
+ if (header.version == 2) {
+ header.incompatible_features = 0;
+ header.compatible_features = 0;
+ header.autoclear_features = 0;
+ header.refcount_order = 4;
+ header.header_length = 72;
+ } else {
+ be64_to_cpus(&header.incompatible_features);
+ be64_to_cpus(&header.compatible_features);
+ be64_to_cpus(&header.autoclear_features);
+ be32_to_cpus(&header.refcount_order);
+ be32_to_cpus(&header.header_length);
+
+ if (header.header_length < 104) {
+ error_setg(errp, "qcow2 header too short");
+ ret = -EINVAL;
+ goto fail;
+ }
+ }
+
+ if (header.header_length > s->cluster_size) {
+ error_setg(errp, "qcow2 header exceeds cluster size");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ if (header.header_length > sizeof(header)) {
+ s->unknown_header_fields_size = header.header_length - sizeof(header);
+ s->unknown_header_fields = g_malloc(s->unknown_header_fields_size);
+ ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields,
+ s->unknown_header_fields_size);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not read unknown qcow2 header "
+ "fields");
+ goto fail;
+ }
+ }
+
+ if (header.backing_file_offset > s->cluster_size) {
+ error_setg(errp, "Invalid backing file offset");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ if (header.backing_file_offset) {
+ ext_end = header.backing_file_offset;
+ } else {
+ ext_end = 1 << header.cluster_bits;
+ }
+
+ /* Handle feature bits */
+ s->incompatible_features = header.incompatible_features;
+ s->compatible_features = header.compatible_features;
+ s->autoclear_features = header.autoclear_features;
+
+ if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) {
+ void *feature_table = NULL;
+ qcow2_read_extensions(bs, header.header_length, ext_end,
+ &feature_table, NULL);
+ report_unsupported_feature(bs, errp, feature_table,
+ s->incompatible_features &
+ ~QCOW2_INCOMPAT_MASK);
+ ret = -ENOTSUP;
+ g_free(feature_table);
+ goto fail;
+ }
+
+ if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
+ /* Corrupt images may not be written to unless they are being repaired
+ */
+ if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
+ error_setg(errp, "qcow2: Image is corrupt; cannot be opened "
+ "read/write");
+ ret = -EACCES;
+ goto fail;
+ }
+ }
+
+ /* Check support for various header values */
+ if (header.refcount_order > 6) {
+ error_setg(errp, "Reference count entry width too large; may not "
+ "exceed 64 bits");
+ ret = -EINVAL;
+ goto fail;
+ }
+ s->refcount_order = header.refcount_order;
+ s->refcount_bits = 1 << s->refcount_order;
+ s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1);
+ s->refcount_max += s->refcount_max - 1;
+
+ if (header.crypt_method > QCOW_CRYPT_AES) {
+ error_setg(errp, "Unsupported encryption method: %" PRIu32,
+ header.crypt_method);
+ ret = -EINVAL;
+ goto fail;
+ }
+ if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) {
+ error_setg(errp, "AES cipher not available");
+ ret = -EINVAL;
+ goto fail;
+ }
+ s->crypt_method_header = header.crypt_method;
+ if (s->crypt_method_header) {
+ bs->encrypted = 1;
+ }
+
+ s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
+ s->l2_size = 1 << s->l2_bits;
+ /* 2^(s->refcount_order - 3) is the refcount width in bytes */
+ s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3);
+ s->refcount_block_size = 1 << s->refcount_block_bits;
+ bs->total_sectors = header.size / 512;
+ s->csize_shift = (62 - (s->cluster_bits - 8));
+ s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
+ s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
+
+ s->refcount_table_offset = header.refcount_table_offset;
+ s->refcount_table_size =
+ header.refcount_table_clusters << (s->cluster_bits - 3);
+
+ if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) {
+ error_setg(errp, "Reference count table too large");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ ret = validate_table_offset(bs, s->refcount_table_offset,
+ s->refcount_table_size, sizeof(uint64_t));
+ if (ret < 0) {
+ error_setg(errp, "Invalid reference count table offset");
+ goto fail;
+ }
+
+ /* Snapshot table offset/length */
+ if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) {
+ error_setg(errp, "Too many snapshots");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ ret = validate_table_offset(bs, header.snapshots_offset,
+ header.nb_snapshots,
+ sizeof(QCowSnapshotHeader));
+ if (ret < 0) {
+ error_setg(errp, "Invalid snapshot table offset");
+ goto fail;
+ }
+
+ /* read the level 1 table */
+ if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) {
+ error_setg(errp, "Active L1 table too large");
+ ret = -EFBIG;
+ goto fail;
+ }
+ s->l1_size = header.l1_size;
+
+ l1_vm_state_index = size_to_l1(s, header.size);
+ if (l1_vm_state_index > INT_MAX) {
+ error_setg(errp, "Image is too big");
+ ret = -EFBIG;
+ goto fail;
+ }
+ s->l1_vm_state_index = l1_vm_state_index;
+
+ /* the L1 table must contain at least enough entries to put
+ header.size bytes */
+ if (s->l1_size < s->l1_vm_state_index) {
+ error_setg(errp, "L1 table is too small");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ ret = validate_table_offset(bs, header.l1_table_offset,
+ header.l1_size, sizeof(uint64_t));
+ if (ret < 0) {
+ error_setg(errp, "Invalid L1 table offset");
+ goto fail;
+ }
+ s->l1_table_offset = header.l1_table_offset;
+
+
+ if (s->l1_size > 0) {
+ s->l1_table = qemu_try_blockalign(bs->file,
+ align_offset(s->l1_size * sizeof(uint64_t), 512));
+ if (s->l1_table == NULL) {
+ error_setg(errp, "Could not allocate L1 table");
+ ret = -ENOMEM;
+ goto fail;
+ }
+ ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
+ s->l1_size * sizeof(uint64_t));
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not read L1 table");
+ goto fail;
+ }
+ for(i = 0;i < s->l1_size; i++) {
+ be64_to_cpus(&s->l1_table[i]);
+ }
+ }
+
+ /* get L2 table/refcount block cache size from command line options */
+ opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort);
+ qemu_opts_absorb_qdict(opts, options, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size,
+ &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ l2_cache_size /= s->cluster_size;
+ if (l2_cache_size < MIN_L2_CACHE_SIZE) {
+ l2_cache_size = MIN_L2_CACHE_SIZE;
+ }
+ if (l2_cache_size > INT_MAX) {
+ error_setg(errp, "L2 cache size too big");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ refcount_cache_size /= s->cluster_size;
+ if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) {
+ refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE;
+ }
+ if (refcount_cache_size > INT_MAX) {
+ error_setg(errp, "Refcount cache size too big");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ /* alloc L2 table/refcount block cache */
+ s->l2_table_cache = qcow2_cache_create(bs, l2_cache_size);
+ s->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size);
+ if (s->l2_table_cache == NULL || s->refcount_block_cache == NULL) {
+ error_setg(errp, "Could not allocate metadata caches");
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ s->cluster_cache = g_malloc(s->cluster_size);
+ /* one more sector for decompressed data alignment */
+ s->cluster_data = qemu_try_blockalign(bs->file, QCOW_MAX_CRYPT_CLUSTERS
+ * s->cluster_size + 512);
+ if (s->cluster_data == NULL) {
+ error_setg(errp, "Could not allocate temporary cluster buffer");
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ s->cluster_cache_offset = -1;
+ s->flags = flags;
+
+ ret = qcow2_refcount_init(bs);
+ if (ret != 0) {
+ error_setg_errno(errp, -ret, "Could not initialize refcount handling");
+ goto fail;
+ }
+
+ QLIST_INIT(&s->cluster_allocs);
+ QTAILQ_INIT(&s->discards);
+
+ /* read qcow2 extensions */
+ if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL,
+ &local_err)) {
+ error_propagate(errp, local_err);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ /* read the backing file name */
+ if (header.backing_file_offset != 0) {
+ len = header.backing_file_size;
+ if (len > MIN(1023, s->cluster_size - header.backing_file_offset) ||
+ len >= sizeof(bs->backing_file)) {
+ error_setg(errp, "Backing file name too long");
+ ret = -EINVAL;
+ goto fail;
+ }
+ ret = bdrv_pread(bs->file, header.backing_file_offset,
+ bs->backing_file, len);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not read backing file name");
+ goto fail;
+ }
+ bs->backing_file[len] = '\0';
+ s->image_backing_file = g_strdup(bs->backing_file);
+ }
+
+ /* Internal snapshots */
+ s->snapshots_offset = header.snapshots_offset;
+ s->nb_snapshots = header.nb_snapshots;
+
+ ret = qcow2_read_snapshots(bs);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not read snapshots");
+ goto fail;
+ }
+
+ /* Clear unknown autoclear feature bits */
+ if (!bs->read_only && !(flags & BDRV_O_INCOMING) && s->autoclear_features) {
+ s->autoclear_features = 0;
+ ret = qcow2_update_header(bs);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not update qcow2 header");
+ goto fail;
+ }
+ }
+
+ /* Initialise locks */
+ qemu_co_mutex_init(&s->lock);
+
+ /* Repair image if dirty */
+ if (!(flags & (BDRV_O_CHECK | BDRV_O_INCOMING)) && !bs->read_only &&
+ (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) {
+ BdrvCheckResult result = {0};
+
+ ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not repair dirty image");
+ goto fail;
+ }
+ }
+
+ /* Enable lazy_refcounts according to image and command line options */
+ s->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS,
+ (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));
+
+ s->discard_passthrough[QCOW2_DISCARD_NEVER] = false;
+ s->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true;
+ s->discard_passthrough[QCOW2_DISCARD_REQUEST] =
+ qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST,
+ flags & BDRV_O_UNMAP);
+ s->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] =
+ qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true);
+ s->discard_passthrough[QCOW2_DISCARD_OTHER] =
+ qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false);
+
+ opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP);
+ opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE);
+ if (opt_overlap_check_template && opt_overlap_check &&
+ strcmp(opt_overlap_check_template, opt_overlap_check))
+ {
+ error_setg(errp, "Conflicting values for qcow2 options '"
+ QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE
+ "' ('%s')", opt_overlap_check, opt_overlap_check_template);
+ ret = -EINVAL;
+ goto fail;
+ }
+ if (!opt_overlap_check) {
+ opt_overlap_check = opt_overlap_check_template ?: "cached";
+ }
+
+ if (!strcmp(opt_overlap_check, "none")) {
+ overlap_check_template = 0;
+ } else if (!strcmp(opt_overlap_check, "constant")) {
+ overlap_check_template = QCOW2_OL_CONSTANT;
+ } else if (!strcmp(opt_overlap_check, "cached")) {
+ overlap_check_template = QCOW2_OL_CACHED;
+ } else if (!strcmp(opt_overlap_check, "all")) {
+ overlap_check_template = QCOW2_OL_ALL;
+ } else {
+ error_setg(errp, "Unsupported value '%s' for qcow2 option "
+ "'overlap-check'. Allowed are either of the following: "
+ "none, constant, cached, all", opt_overlap_check);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ s->overlap_check = 0;
+ for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) {
+ /* overlap-check defines a template bitmask, but every flag may be
+ * overwritten through the associated boolean option */
+ s->overlap_check |=
+ qemu_opt_get_bool(opts, overlap_bool_option_names[i],
+ overlap_check_template & (1 << i)) << i;
+ }
+
+ qemu_opts_del(opts);
+ opts = NULL;
+
+ if (s->use_lazy_refcounts && s->qcow_version < 3) {
+ error_setg(errp, "Lazy refcounts require a qcow2 image with at least "
+ "qemu 1.1 compatibility level");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+#ifdef DEBUG_ALLOC
+ {
+ BdrvCheckResult result = {0};
+ qcow2_check_refcounts(bs, &result, 0);
+ }
+#endif
+ return ret;
+
+ fail:
+ qemu_opts_del(opts);
+ g_free(s->unknown_header_fields);
+ cleanup_unknown_header_ext(bs);
+ qcow2_free_snapshots(bs);
+ qcow2_refcount_close(bs);
+ qemu_vfree(s->l1_table);
+ /* else pre-write overlap checks in cache_destroy may crash */
+ s->l1_table = NULL;
+ if (s->l2_table_cache) {
+ qcow2_cache_destroy(bs, s->l2_table_cache);
+ }
+ if (s->refcount_block_cache) {
+ qcow2_cache_destroy(bs, s->refcount_block_cache);
+ }
+ g_free(s->cluster_cache);
+ qemu_vfree(s->cluster_data);
+ return ret;
+}
+
+static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+ BDRVQcowState *s = bs->opaque;
+
+ bs->bl.write_zeroes_alignment = s->cluster_sectors;
+}
+
+static int qcow2_set_key(BlockDriverState *bs, const char *key)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint8_t keybuf[16];
+ int len, i;
+ Error *err = NULL;
+
+ memset(keybuf, 0, 16);
+ len = strlen(key);
+ if (len > 16)
+ len = 16;
+ /* XXX: we could compress the chars to 7 bits to increase
+ entropy */
+ for(i = 0;i < len;i++) {
+ keybuf[i] = key[i];
+ }
+ assert(bs->encrypted);
+
+ qcrypto_cipher_free(s->cipher);
+ s->cipher = qcrypto_cipher_new(
+ QCRYPTO_CIPHER_ALG_AES_128,
+ QCRYPTO_CIPHER_MODE_CBC,
+ keybuf, G_N_ELEMENTS(keybuf),
+ &err);
+
+ if (!s->cipher) {
+ /* XXX would be nice if errors in this method could
+ * be properly propagate to the caller. Would need
+ * the bdrv_set_key() API signature to be fixed. */
+ error_free(err);
+ return -1;
+ }
+ return 0;
+}
+
+/* We have no actual commit/abort logic for qcow2, but we need to write out any
+ * unwritten data if we reopen read-only. */
+static int qcow2_reopen_prepare(BDRVReopenState *state,
+ BlockReopenQueue *queue, Error **errp)
+{
+ int ret;
+
+ if ((state->flags & BDRV_O_RDWR) == 0) {
+ ret = bdrv_flush(state->bs);
+ if (ret < 0) {
+ return ret;
+ }
+
+ ret = qcow2_mark_clean(state->bs);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, int *pnum)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t cluster_offset;
+ int index_in_cluster, ret;
+ int64_t status = 0;
+
+ *pnum = nb_sectors;
+ qemu_co_mutex_lock(&s->lock);
+ ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset);
+ qemu_co_mutex_unlock(&s->lock);
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED &&
+ !s->cipher) {
+ index_in_cluster = sector_num & (s->cluster_sectors - 1);
+ cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
+ status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset;
+ }
+ if (ret == QCOW2_CLUSTER_ZERO) {
+ status |= BDRV_BLOCK_ZERO;
+ } else if (ret != QCOW2_CLUSTER_UNALLOCATED) {
+ status |= BDRV_BLOCK_DATA;
+ }
+ return status;
+}
+
+/* handle reading after the end of the backing file */
+int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
+ int64_t sector_num, int nb_sectors)
+{
+ int n1;
+ if ((sector_num + nb_sectors) <= bs->total_sectors)
+ return nb_sectors;
+ if (sector_num >= bs->total_sectors)
+ n1 = 0;
+ else
+ n1 = bs->total_sectors - sector_num;
+
+ qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1));
+
+ return n1;
+}
+
+static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num,
+ int remaining_sectors, QEMUIOVector *qiov)
+{
+ BDRVQcowState *s = bs->opaque;
+ int index_in_cluster, n1;
+ int ret;
+ int cur_nr_sectors; /* number of sectors in current iteration */
+ uint64_t cluster_offset = 0;
+ uint64_t bytes_done = 0;
+ QEMUIOVector hd_qiov;
+ uint8_t *cluster_data = NULL;
+
+ qemu_iovec_init(&hd_qiov, qiov->niov);
+
+ qemu_co_mutex_lock(&s->lock);
+
+ while (remaining_sectors != 0) {
+
+ /* prepare next request */
+ cur_nr_sectors = remaining_sectors;
+ if (s->cipher) {
+ cur_nr_sectors = MIN(cur_nr_sectors,
+ QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors);
+ }
+
+ ret = qcow2_get_cluster_offset(bs, sector_num << 9,
+ &cur_nr_sectors, &cluster_offset);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ index_in_cluster = sector_num & (s->cluster_sectors - 1);
+
+ qemu_iovec_reset(&hd_qiov);
+ qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
+ cur_nr_sectors * 512);
+
+ switch (ret) {
+ case QCOW2_CLUSTER_UNALLOCATED:
+
+ if (bs->backing_hd) {
+ /* read from the base image */
+ n1 = qcow2_backing_read1(bs->backing_hd, &hd_qiov,
+ sector_num, cur_nr_sectors);
+ if (n1 > 0) {
+ QEMUIOVector local_qiov;
+
+ qemu_iovec_init(&local_qiov, hd_qiov.niov);
+ qemu_iovec_concat(&local_qiov, &hd_qiov, 0,
+ n1 * BDRV_SECTOR_SIZE);
+
+ BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
+ qemu_co_mutex_unlock(&s->lock);
+ ret = bdrv_co_readv(bs->backing_hd, sector_num,
+ n1, &local_qiov);
+ qemu_co_mutex_lock(&s->lock);
+
+ qemu_iovec_destroy(&local_qiov);
+
+ if (ret < 0) {
+ goto fail;
+ }
+ }
+ } else {
+ /* Note: in this case, no need to wait */
+ qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors);
+ }
+ break;
+
+ case QCOW2_CLUSTER_ZERO:
+ qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors);
+ break;
+
+ case QCOW2_CLUSTER_COMPRESSED:
+ /* add AIO support for compressed blocks ? */
+ ret = qcow2_decompress_cluster(bs, cluster_offset);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ qemu_iovec_from_buf(&hd_qiov, 0,
+ s->cluster_cache + index_in_cluster * 512,
+ 512 * cur_nr_sectors);
+ break;
+
+ case QCOW2_CLUSTER_NORMAL:
+ if ((cluster_offset & 511) != 0) {
+ ret = -EIO;
+ goto fail;
+ }
+
+ if (bs->encrypted) {
+ assert(s->cipher);
+
+ /*
+ * For encrypted images, read everything into a temporary
+ * contiguous buffer on which the AES functions can work.
+ */
+ if (!cluster_data) {
+ cluster_data =
+ qemu_try_blockalign(bs->file, QCOW_MAX_CRYPT_CLUSTERS
+ * s->cluster_size);
+ if (cluster_data == NULL) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+ }
+
+ assert(cur_nr_sectors <=
+ QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors);
+ qemu_iovec_reset(&hd_qiov);
+ qemu_iovec_add(&hd_qiov, cluster_data,
+ 512 * cur_nr_sectors);
+ }
+
+ BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
+ qemu_co_mutex_unlock(&s->lock);
+ ret = bdrv_co_readv(bs->file,
+ (cluster_offset >> 9) + index_in_cluster,
+ cur_nr_sectors, &hd_qiov);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ goto fail;
+ }
+ if (bs->encrypted) {
+ assert(s->cipher);
+ Error *err = NULL;
+ if (qcow2_encrypt_sectors(s, sector_num, cluster_data,
+ cluster_data, cur_nr_sectors, false,
+ &err) < 0) {
+ error_free(err);
+ ret = -EIO;
+ goto fail;
+ }
+ qemu_iovec_from_buf(qiov, bytes_done,
+ cluster_data, 512 * cur_nr_sectors);
+ }
+ break;
+
+ default:
+ g_assert_not_reached();
+ ret = -EIO;
+ goto fail;
+ }
+
+ remaining_sectors -= cur_nr_sectors;
+ sector_num += cur_nr_sectors;
+ bytes_done += cur_nr_sectors * 512;
+ }
+ ret = 0;
+
+fail:
+ qemu_co_mutex_unlock(&s->lock);
+
+ qemu_iovec_destroy(&hd_qiov);
+ qemu_vfree(cluster_data);
+
+ return ret;
+}
+
+static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
+ int64_t sector_num,
+ int remaining_sectors,
+ QEMUIOVector *qiov)
+{
+ BDRVQcowState *s = bs->opaque;
+ int index_in_cluster;
+ int ret;
+ int cur_nr_sectors; /* number of sectors in current iteration */
+ uint64_t cluster_offset;
+ QEMUIOVector hd_qiov;
+ uint64_t bytes_done = 0;
+ uint8_t *cluster_data = NULL;
+ QCowL2Meta *l2meta = NULL;
+
+ trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num,
+ remaining_sectors);
+
+ qemu_iovec_init(&hd_qiov, qiov->niov);
+
+ s->cluster_cache_offset = -1; /* disable compressed cache */
+
+ qemu_co_mutex_lock(&s->lock);
+
+ while (remaining_sectors != 0) {
+
+ l2meta = NULL;
+
+ trace_qcow2_writev_start_part(qemu_coroutine_self());
+ index_in_cluster = sector_num & (s->cluster_sectors - 1);
+ cur_nr_sectors = remaining_sectors;
+ if (bs->encrypted &&
+ cur_nr_sectors >
+ QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) {
+ cur_nr_sectors =
+ QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster;
+ }
+
+ ret = qcow2_alloc_cluster_offset(bs, sector_num << 9,
+ &cur_nr_sectors, &cluster_offset, &l2meta);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ assert((cluster_offset & 511) == 0);
+
+ qemu_iovec_reset(&hd_qiov);
+ qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
+ cur_nr_sectors * 512);
+
+ if (bs->encrypted) {
+ Error *err = NULL;
+ assert(s->cipher);
+ if (!cluster_data) {
+ cluster_data = qemu_try_blockalign(bs->file,
+ QCOW_MAX_CRYPT_CLUSTERS
+ * s->cluster_size);
+ if (cluster_data == NULL) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+ }
+
+ assert(hd_qiov.size <=
+ QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
+ qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size);
+
+ if (qcow2_encrypt_sectors(s, sector_num, cluster_data,
+ cluster_data, cur_nr_sectors,
+ true, &err) < 0) {
+ error_free(err);
+ ret = -EIO;
+ goto fail;
+ }
+
+ qemu_iovec_reset(&hd_qiov);
+ qemu_iovec_add(&hd_qiov, cluster_data,
+ cur_nr_sectors * 512);
+ }
+
+ ret = qcow2_pre_write_overlap_check(bs, 0,
+ cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE,
+ cur_nr_sectors * BDRV_SECTOR_SIZE);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ qemu_co_mutex_unlock(&s->lock);
+ BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
+ trace_qcow2_writev_data(qemu_coroutine_self(),
+ (cluster_offset >> 9) + index_in_cluster);
+ ret = bdrv_co_writev(bs->file,
+ (cluster_offset >> 9) + index_in_cluster,
+ cur_nr_sectors, &hd_qiov);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ while (l2meta != NULL) {
+ QCowL2Meta *next;
+
+ ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ /* Take the request off the list of running requests */
+ if (l2meta->nb_clusters != 0) {
+ QLIST_REMOVE(l2meta, next_in_flight);
+ }
+
+ qemu_co_queue_restart_all(&l2meta->dependent_requests);
+
+ next = l2meta->next;
+ g_free(l2meta);
+ l2meta = next;
+ }
+
+ remaining_sectors -= cur_nr_sectors;
+ sector_num += cur_nr_sectors;
+ bytes_done += cur_nr_sectors * 512;
+ trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors);
+ }
+ ret = 0;
+
+fail:
+ qemu_co_mutex_unlock(&s->lock);
+
+ while (l2meta != NULL) {
+ QCowL2Meta *next;
+
+ if (l2meta->nb_clusters != 0) {
+ QLIST_REMOVE(l2meta, next_in_flight);
+ }
+ qemu_co_queue_restart_all(&l2meta->dependent_requests);
+
+ next = l2meta->next;
+ g_free(l2meta);
+ l2meta = next;
+ }
+
+ qemu_iovec_destroy(&hd_qiov);
+ qemu_vfree(cluster_data);
+ trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
+
+ return ret;
+}
+
+static void qcow2_close(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ qemu_vfree(s->l1_table);
+ /* else pre-write overlap checks in cache_destroy may crash */
+ s->l1_table = NULL;
+
+ if (!(bs->open_flags & BDRV_O_INCOMING)) {
+ int ret1, ret2;
+
+ ret1 = qcow2_cache_flush(bs, s->l2_table_cache);
+ ret2 = qcow2_cache_flush(bs, s->refcount_block_cache);
+
+ if (ret1) {
+ error_report("Failed to flush the L2 table cache: %s",
+ strerror(-ret1));
+ }
+ if (ret2) {
+ error_report("Failed to flush the refcount block cache: %s",
+ strerror(-ret2));
+ }
+
+ if (!ret1 && !ret2) {
+ qcow2_mark_clean(bs);
+ }
+ }
+
+ qcow2_cache_destroy(bs, s->l2_table_cache);
+ qcow2_cache_destroy(bs, s->refcount_block_cache);
+
+ qcrypto_cipher_free(s->cipher);
+ s->cipher = NULL;
+
+ g_free(s->unknown_header_fields);
+ cleanup_unknown_header_ext(bs);
+
+ g_free(s->image_backing_file);
+ g_free(s->image_backing_format);
+
+ g_free(s->cluster_cache);
+ qemu_vfree(s->cluster_data);
+ qcow2_refcount_close(bs);
+ qcow2_free_snapshots(bs);
+}
+
+static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp)
+{
+ BDRVQcowState *s = bs->opaque;
+ int flags = s->flags;
+ QCryptoCipher *cipher = NULL;
+ QDict *options;
+ Error *local_err = NULL;
+ int ret;
+
+ /*
+ * Backing files are read-only which makes all of their metadata immutable,
+ * that means we don't have to worry about reopening them here.
+ */
+
+ cipher = s->cipher;
+ s->cipher = NULL;
+
+ qcow2_close(bs);
+
+ bdrv_invalidate_cache(bs->file, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
+
+ memset(s, 0, sizeof(BDRVQcowState));
+ options = qdict_clone_shallow(bs->options);
+
+ ret = qcow2_open(bs, options, flags, &local_err);
+ QDECREF(options);
+ if (local_err) {
+ error_setg(errp, "Could not reopen qcow2 layer: %s",
+ error_get_pretty(local_err));
+ error_free(local_err);
+ return;
+ } else if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not reopen qcow2 layer");
+ return;
+ }
+
+ s->cipher = cipher;
+}
+
+static size_t header_ext_add(char *buf, uint32_t magic, const void *s,
+ size_t len, size_t buflen)
+{
+ QCowExtension *ext_backing_fmt = (QCowExtension*) buf;
+ size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7);
+
+ if (buflen < ext_len) {
+ return -ENOSPC;
+ }
+
+ *ext_backing_fmt = (QCowExtension) {
+ .magic = cpu_to_be32(magic),
+ .len = cpu_to_be32(len),
+ };
+ memcpy(buf + sizeof(QCowExtension), s, len);
+
+ return ext_len;
+}
+
+/*
+ * Updates the qcow2 header, including the variable length parts of it, i.e.
+ * the backing file name and all extensions. qcow2 was not designed to allow
+ * such changes, so if we run out of space (we can only use the first cluster)
+ * this function may fail.
+ *
+ * Returns 0 on success, -errno in error cases.
+ */
+int qcow2_update_header(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ QCowHeader *header;
+ char *buf;
+ size_t buflen = s->cluster_size;
+ int ret;
+ uint64_t total_size;
+ uint32_t refcount_table_clusters;
+ size_t header_length;
+ Qcow2UnknownHeaderExtension *uext;
+
+ buf = qemu_blockalign(bs, buflen);
+
+ /* Header structure */
+ header = (QCowHeader*) buf;
+
+ if (buflen < sizeof(*header)) {
+ ret = -ENOSPC;
+ goto fail;
+ }
+
+ header_length = sizeof(*header) + s->unknown_header_fields_size;
+ total_size = bs->total_sectors * BDRV_SECTOR_SIZE;
+ refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
+
+ *header = (QCowHeader) {
+ /* Version 2 fields */
+ .magic = cpu_to_be32(QCOW_MAGIC),
+ .version = cpu_to_be32(s->qcow_version),
+ .backing_file_offset = 0,
+ .backing_file_size = 0,
+ .cluster_bits = cpu_to_be32(s->cluster_bits),
+ .size = cpu_to_be64(total_size),
+ .crypt_method = cpu_to_be32(s->crypt_method_header),
+ .l1_size = cpu_to_be32(s->l1_size),
+ .l1_table_offset = cpu_to_be64(s->l1_table_offset),
+ .refcount_table_offset = cpu_to_be64(s->refcount_table_offset),
+ .refcount_table_clusters = cpu_to_be32(refcount_table_clusters),
+ .nb_snapshots = cpu_to_be32(s->nb_snapshots),
+ .snapshots_offset = cpu_to_be64(s->snapshots_offset),
+
+ /* Version 3 fields */
+ .incompatible_features = cpu_to_be64(s->incompatible_features),
+ .compatible_features = cpu_to_be64(s->compatible_features),
+ .autoclear_features = cpu_to_be64(s->autoclear_features),
+ .refcount_order = cpu_to_be32(s->refcount_order),
+ .header_length = cpu_to_be32(header_length),
+ };
+
+ /* For older versions, write a shorter header */
+ switch (s->qcow_version) {
+ case 2:
+ ret = offsetof(QCowHeader, incompatible_features);
+ break;
+ case 3:
+ ret = sizeof(*header);
+ break;
+ default:
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ buf += ret;
+ buflen -= ret;
+ memset(buf, 0, buflen);
+
+ /* Preserve any unknown field in the header */
+ if (s->unknown_header_fields_size) {
+ if (buflen < s->unknown_header_fields_size) {
+ ret = -ENOSPC;
+ goto fail;
+ }
+
+ memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size);
+ buf += s->unknown_header_fields_size;
+ buflen -= s->unknown_header_fields_size;
+ }
+
+ /* Backing file format header extension */
+ if (s->image_backing_format) {
+ ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT,
+ s->image_backing_format,
+ strlen(s->image_backing_format),
+ buflen);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ buf += ret;
+ buflen -= ret;
+ }
+
+ /* Feature table */
+ Qcow2Feature features[] = {
+ {
+ .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
+ .bit = QCOW2_INCOMPAT_DIRTY_BITNR,
+ .name = "dirty bit",
+ },
+ {
+ .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
+ .bit = QCOW2_INCOMPAT_CORRUPT_BITNR,
+ .name = "corrupt bit",
+ },
+ {
+ .type = QCOW2_FEAT_TYPE_COMPATIBLE,
+ .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
+ .name = "lazy refcounts",
+ },
+ };
+
+ ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE,
+ features, sizeof(features), buflen);
+ if (ret < 0) {
+ goto fail;
+ }
+ buf += ret;
+ buflen -= ret;
+
+ /* Keep unknown header extensions */
+ QLIST_FOREACH(uext, &s->unknown_header_ext, next) {
+ ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ buf += ret;
+ buflen -= ret;
+ }
+
+ /* End of header extensions */
+ ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ buf += ret;
+ buflen -= ret;
+
+ /* Backing file name */
+ if (s->image_backing_file) {
+ size_t backing_file_len = strlen(s->image_backing_file);
+
+ if (buflen < backing_file_len) {
+ ret = -ENOSPC;
+ goto fail;
+ }
+
+ /* Using strncpy is ok here, since buf is not NUL-terminated. */
+ strncpy(buf, s->image_backing_file, buflen);
+
+ header->backing_file_offset = cpu_to_be64(buf - ((char*) header));
+ header->backing_file_size = cpu_to_be32(backing_file_len);
+ }
+
+ /* Write the new header */
+ ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ ret = 0;
+fail:
+ qemu_vfree(header);
+ return ret;
+}
+
+static int qcow2_change_backing_file(BlockDriverState *bs,
+ const char *backing_file, const char *backing_fmt)
+{
+ BDRVQcowState *s = bs->opaque;
+
+ pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
+ pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
+
+ g_free(s->image_backing_file);
+ g_free(s->image_backing_format);
+
+ s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL;
+ s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL;
+
+ return qcow2_update_header(bs);
+}
+
+static int preallocate(BlockDriverState *bs)
+{
+ uint64_t nb_sectors;
+ uint64_t offset;
+ uint64_t host_offset = 0;
+ int num;
+ int ret;
+ QCowL2Meta *meta;
+
+ nb_sectors = bdrv_nb_sectors(bs);
+ offset = 0;
+
+ while (nb_sectors) {
+ num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS);
+ ret = qcow2_alloc_cluster_offset(bs, offset, &num,
+ &host_offset, &meta);
+ if (ret < 0) {
+ return ret;
+ }
+
+ while (meta) {
+ QCowL2Meta *next = meta->next;
+
+ ret = qcow2_alloc_cluster_link_l2(bs, meta);
+ if (ret < 0) {
+ qcow2_free_any_clusters(bs, meta->alloc_offset,
+ meta->nb_clusters, QCOW2_DISCARD_NEVER);
+ return ret;
+ }
+
+ /* There are no dependent requests, but we need to remove our
+ * request from the list of in-flight requests */
+ QLIST_REMOVE(meta, next_in_flight);
+
+ g_free(meta);
+ meta = next;
+ }
+
+ /* TODO Preallocate data if requested */
+
+ nb_sectors -= num;
+ offset += num << BDRV_SECTOR_BITS;
+ }
+
+ /*
+ * It is expected that the image file is large enough to actually contain
+ * all of the allocated clusters (otherwise we get failing reads after
+ * EOF). Extend the image to the last allocated sector.
+ */
+ if (host_offset != 0) {
+ uint8_t buf[BDRV_SECTOR_SIZE];
+ memset(buf, 0, BDRV_SECTOR_SIZE);
+ ret = bdrv_write(bs->file, (host_offset >> BDRV_SECTOR_BITS) + num - 1,
+ buf, 1);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static int qcow2_create2(const char *filename, int64_t total_size,
+ const char *backing_file, const char *backing_format,
+ int flags, size_t cluster_size, PreallocMode prealloc,
+ QemuOpts *opts, int version, int refcount_order,
+ Error **errp)
+{
+ /* Calculate cluster_bits */
+ int cluster_bits;
+ cluster_bits = ctz32(cluster_size);
+ if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS ||
+ (1 << cluster_bits) != cluster_size)
+ {
+ error_setg(errp, "Cluster size must be a power of two between %d and "
+ "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10));
+ return -EINVAL;
+ }
+
+ /*
+ * Open the image file and write a minimal qcow2 header.
+ *
+ * We keep things simple and start with a zero-sized image. We also
+ * do without refcount blocks or a L1 table for now. We'll fix the
+ * inconsistency later.
+ *
+ * We do need a refcount table because growing the refcount table means
+ * allocating two new refcount blocks - the seconds of which would be at
+ * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
+ * size for any qcow2 image.
+ */
+ BlockDriverState* bs;
+ QCowHeader *header;
+ uint64_t* refcount_table;
+ Error *local_err = NULL;
+ int ret;
+
+ if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
+ /* Note: The following calculation does not need to be exact; if it is a
+ * bit off, either some bytes will be "leaked" (which is fine) or we
+ * will need to increase the file size by some bytes (which is fine,
+ * too, as long as the bulk is allocated here). Therefore, using
+ * floating point arithmetic is fine. */
+ int64_t meta_size = 0;
+ uint64_t nreftablee, nrefblocke, nl1e, nl2e;
+ int64_t aligned_total_size = align_offset(total_size, cluster_size);
+ int refblock_bits, refblock_size;
+ /* refcount entry size in bytes */
+ double rces = (1 << refcount_order) / 8.;
+
+ /* see qcow2_open() */
+ refblock_bits = cluster_bits - (refcount_order - 3);
+ refblock_size = 1 << refblock_bits;
+
+ /* header: 1 cluster */
+ meta_size += cluster_size;
+
+ /* total size of L2 tables */
+ nl2e = aligned_total_size / cluster_size;
+ nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t));
+ meta_size += nl2e * sizeof(uint64_t);
+
+ /* total size of L1 tables */
+ nl1e = nl2e * sizeof(uint64_t) / cluster_size;
+ nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t));
+ meta_size += nl1e * sizeof(uint64_t);
+
+ /* total size of refcount blocks
+ *
+ * note: every host cluster is reference-counted, including metadata
+ * (even refcount blocks are recursively included).
+ * Let:
+ * a = total_size (this is the guest disk size)
+ * m = meta size not including refcount blocks and refcount tables
+ * c = cluster size
+ * y1 = number of refcount blocks entries
+ * y2 = meta size including everything
+ * rces = refcount entry size in bytes
+ * then,
+ * y1 = (y2 + a)/c
+ * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m
+ * we can get y1:
+ * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c)
+ */
+ nrefblocke = (aligned_total_size + meta_size + cluster_size)
+ / (cluster_size - rces - rces * sizeof(uint64_t)
+ / cluster_size);
+ meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size;
+
+ /* total size of refcount tables */
+ nreftablee = nrefblocke / refblock_size;
+ nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t));
+ meta_size += nreftablee * sizeof(uint64_t);
+
+ qemu_opt_set_number(opts, BLOCK_OPT_SIZE,
+ aligned_total_size + meta_size, &error_abort);
+ qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc],
+ &error_abort);
+ }
+
+ ret = bdrv_create_file(filename, opts, &local_err);
+ if (ret < 0) {
+ error_propagate(errp, local_err);
+ return ret;
+ }
+
+ bs = NULL;
+ ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
+ NULL, &local_err);
+ if (ret < 0) {
+ error_propagate(errp, local_err);
+ return ret;
+ }
+
+ /* Write the header */
+ QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header));
+ header = g_malloc0(cluster_size);
+ *header = (QCowHeader) {
+ .magic = cpu_to_be32(QCOW_MAGIC),
+ .version = cpu_to_be32(version),
+ .cluster_bits = cpu_to_be32(cluster_bits),
+ .size = cpu_to_be64(0),
+ .l1_table_offset = cpu_to_be64(0),
+ .l1_size = cpu_to_be32(0),
+ .refcount_table_offset = cpu_to_be64(cluster_size),
+ .refcount_table_clusters = cpu_to_be32(1),
+ .refcount_order = cpu_to_be32(refcount_order),
+ .header_length = cpu_to_be32(sizeof(*header)),
+ };
+
+ if (flags & BLOCK_FLAG_ENCRYPT) {
+ header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
+ } else {
+ header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
+ }
+
+ if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) {
+ header->compatible_features |=
+ cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS);
+ }
+
+ ret = bdrv_pwrite(bs, 0, header, cluster_size);
+ g_free(header);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not write qcow2 header");
+ goto out;
+ }
+
+ /* Write a refcount table with one refcount block */
+ refcount_table = g_malloc0(2 * cluster_size);
+ refcount_table[0] = cpu_to_be64(2 * cluster_size);
+ ret = bdrv_pwrite(bs, cluster_size, refcount_table, 2 * cluster_size);
+ g_free(refcount_table);
+
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not write refcount table");
+ goto out;
+ }
+
+ bdrv_unref(bs);
+ bs = NULL;
+
+ /*
+ * And now open the image and make it consistent first (i.e. increase the
+ * refcount of the cluster that is occupied by the header and the refcount
+ * table)
+ */
+ ret = bdrv_open(&bs, filename, NULL, NULL,
+ BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH,
+ &bdrv_qcow2, &local_err);
+ if (ret < 0) {
+ error_propagate(errp, local_err);
+ goto out;
+ }
+
+ ret = qcow2_alloc_clusters(bs, 3 * cluster_size);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 "
+ "header and refcount table");
+ goto out;
+
+ } else if (ret != 0) {
+ error_report("Huh, first cluster in empty image is already in use?");
+ abort();
+ }
+
+ /* Okay, now that we have a valid image, let's give it the right size */
+ ret = bdrv_truncate(bs, total_size);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not resize image");
+ goto out;
+ }
+
+ /* Want a backing file? There you go.*/
+ if (backing_file) {
+ ret = bdrv_change_backing_file(bs, backing_file, backing_format);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not assign backing file '%s' "
+ "with format '%s'", backing_file, backing_format);
+ goto out;
+ }
+ }
+
+ /* And if we're supposed to preallocate metadata, do that now */
+ if (prealloc != PREALLOC_MODE_OFF) {
+ BDRVQcowState *s = bs->opaque;
+ qemu_co_mutex_lock(&s->lock);
+ ret = preallocate(bs);
+ qemu_co_mutex_unlock(&s->lock);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not preallocate metadata");
+ goto out;
+ }
+ }
+
+ bdrv_unref(bs);
+ bs = NULL;
+
+ /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */
+ ret = bdrv_open(&bs, filename, NULL, NULL,
+ BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING,
+ &bdrv_qcow2, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ goto out;
+ }
+
+ ret = 0;
+out:
+ if (bs) {
+ bdrv_unref(bs);
+ }
+ return ret;
+}
+
+static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
+{
+ char *backing_file = NULL;
+ char *backing_fmt = NULL;
+ char *buf = NULL;
+ uint64_t size = 0;
+ int flags = 0;
+ size_t cluster_size = DEFAULT_CLUSTER_SIZE;
+ PreallocMode prealloc;
+ int version = 3;
+ uint64_t refcount_bits = 16;
+ int refcount_order;
+ Error *local_err = NULL;
+ int ret;
+
+ /* Read out options */
+ 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);
+ if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
+ flags |= BLOCK_FLAG_ENCRYPT;
+ }
+ cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE,
+ DEFAULT_CLUSTER_SIZE);
+ buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
+ prealloc = qapi_enum_parse(PreallocMode_lookup, buf,
+ PREALLOC_MODE_MAX, PREALLOC_MODE_OFF,
+ &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ ret = -EINVAL;
+ goto finish;
+ }
+ g_free(buf);
+ buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL);
+ if (!buf) {
+ /* keep the default */
+ } else if (!strcmp(buf, "0.10")) {
+ version = 2;
+ } else if (!strcmp(buf, "1.1")) {
+ version = 3;
+ } else {
+ error_setg(errp, "Invalid compatibility level: '%s'", buf);
+ ret = -EINVAL;
+ goto finish;
+ }
+
+ if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) {
+ flags |= BLOCK_FLAG_LAZY_REFCOUNTS;
+ }
+
+ if (backing_file && prealloc != PREALLOC_MODE_OFF) {
+ error_setg(errp, "Backing file and preallocation cannot be used at "
+ "the same time");
+ ret = -EINVAL;
+ goto finish;
+ }
+
+ if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) {
+ error_setg(errp, "Lazy refcounts only supported with compatibility "
+ "level 1.1 and above (use compat=1.1 or greater)");
+ ret = -EINVAL;
+ goto finish;
+ }
+
+ refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS,
+ refcount_bits);
+ if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) {
+ error_setg(errp, "Refcount width must be a power of two and may not "
+ "exceed 64 bits");
+ ret = -EINVAL;
+ goto finish;
+ }
+
+ if (version < 3 && refcount_bits != 16) {
+ error_setg(errp, "Different refcount widths than 16 bits require "
+ "compatibility level 1.1 or above (use compat=1.1 or "
+ "greater)");
+ ret = -EINVAL;
+ goto finish;
+ }
+
+ refcount_order = ctz32(refcount_bits);
+
+ ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags,
+ cluster_size, prealloc, opts, version, refcount_order,
+ &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ }
+
+finish:
+ g_free(backing_file);
+ g_free(backing_fmt);
+ g_free(buf);
+ return ret;
+}
+
+static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, BdrvRequestFlags flags)
+{
+ int ret;
+ BDRVQcowState *s = bs->opaque;
+
+ /* Emulate misaligned zero writes */
+ if (sector_num % s->cluster_sectors || nb_sectors % s->cluster_sectors) {
+ return -ENOTSUP;
+ }
+
+ /* Whatever is left can use real zero clusters */
+ qemu_co_mutex_lock(&s->lock);
+ ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS,
+ nb_sectors);
+ qemu_co_mutex_unlock(&s->lock);
+
+ return ret;
+}
+
+static coroutine_fn int qcow2_co_discard(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors)
+{
+ int ret;
+ BDRVQcowState *s = bs->opaque;
+
+ qemu_co_mutex_lock(&s->lock);
+ ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS,
+ nb_sectors, QCOW2_DISCARD_REQUEST, false);
+ qemu_co_mutex_unlock(&s->lock);
+ return ret;
+}
+
+static int qcow2_truncate(BlockDriverState *bs, int64_t offset)
+{
+ BDRVQcowState *s = bs->opaque;
+ int64_t new_l1_size;
+ int ret;
+
+ if (offset & 511) {
+ error_report("The new size must be a multiple of 512");
+ return -EINVAL;
+ }
+
+ /* cannot proceed if image has snapshots */
+ if (s->nb_snapshots) {
+ error_report("Can't resize an image which has snapshots");
+ return -ENOTSUP;
+ }
+
+ /* shrinking is currently not supported */
+ if (offset < bs->total_sectors * 512) {
+ error_report("qcow2 doesn't support shrinking images yet");
+ return -ENOTSUP;
+ }
+
+ new_l1_size = size_to_l1(s, offset);
+ ret = qcow2_grow_l1_table(bs, new_l1_size, true);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* write updated header.size */
+ offset = cpu_to_be64(offset);
+ ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size),
+ &offset, sizeof(uint64_t));
+ if (ret < 0) {
+ return ret;
+ }
+
+ s->l1_vm_state_index = new_l1_size;
+ return 0;
+}
+
+/* XXX: put compressed sectors first, then all the cluster aligned
+ tables to avoid losing bytes in alignment */
+static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
+ const uint8_t *buf, int nb_sectors)
+{
+ BDRVQcowState *s = bs->opaque;
+ z_stream strm;
+ int ret, out_len;
+ uint8_t *out_buf;
+ uint64_t cluster_offset;
+
+ if (nb_sectors == 0) {
+ /* align end of file to a sector boundary to ease reading with
+ sector based I/Os */
+ cluster_offset = bdrv_getlength(bs->file);
+ return bdrv_truncate(bs->file, cluster_offset);
+ }
+
+ if (nb_sectors != s->cluster_sectors) {
+ ret = -EINVAL;
+
+ /* Zero-pad last write if image size is not cluster aligned */
+ if (sector_num + nb_sectors == bs->total_sectors &&
+ nb_sectors < s->cluster_sectors) {
+ uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size);
+ memset(pad_buf, 0, s->cluster_size);
+ memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE);
+ ret = qcow2_write_compressed(bs, sector_num,
+ pad_buf, s->cluster_sectors);
+ qemu_vfree(pad_buf);
+ }
+ return ret;
+ }
+
+ out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
+
+ /* best compression, small window, no zlib header */
+ memset(&strm, 0, sizeof(strm));
+ ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
+ Z_DEFLATED, -12,
+ 9, Z_DEFAULT_STRATEGY);
+ if (ret != 0) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ strm.avail_in = s->cluster_size;
+ strm.next_in = (uint8_t *)buf;
+ strm.avail_out = s->cluster_size;
+ strm.next_out = out_buf;
+
+ ret = deflate(&strm, Z_FINISH);
+ if (ret != Z_STREAM_END && ret != Z_OK) {
+ deflateEnd(&strm);
+ ret = -EINVAL;
+ goto fail;
+ }
+ out_len = strm.next_out - out_buf;
+
+ deflateEnd(&strm);
+
+ if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
+ /* could not compress: write normal cluster */
+ ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors);
+ if (ret < 0) {
+ goto fail;
+ }
+ } else {
+ cluster_offset = qcow2_alloc_compressed_cluster_offset(bs,
+ sector_num << 9, out_len);
+ if (!cluster_offset) {
+ ret = -EIO;
+ goto fail;
+ }
+ cluster_offset &= s->cluster_offset_mask;
+
+ ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
+ ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len);
+ if (ret < 0) {
+ goto fail;
+ }
+ }
+
+ ret = 0;
+fail:
+ g_free(out_buf);
+ return ret;
+}
+
+static int make_completely_empty(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ int ret, l1_clusters;
+ int64_t offset;
+ uint64_t *new_reftable = NULL;
+ uint64_t rt_entry, l1_size2;
+ struct {
+ uint64_t l1_offset;
+ uint64_t reftable_offset;
+ uint32_t reftable_clusters;
+ } QEMU_PACKED l1_ofs_rt_ofs_cls;
+
+ ret = qcow2_cache_empty(bs, s->l2_table_cache);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ ret = qcow2_cache_empty(bs, s->refcount_block_cache);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ /* Refcounts will be broken utterly */
+ ret = qcow2_mark_dirty(bs);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
+
+ l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
+ l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t);
+
+ /* After this call, neither the in-memory nor the on-disk refcount
+ * information accurately describe the actual references */
+
+ ret = bdrv_write_zeroes(bs->file, s->l1_table_offset / BDRV_SECTOR_SIZE,
+ l1_clusters * s->cluster_sectors, 0);
+ if (ret < 0) {
+ goto fail_broken_refcounts;
+ }
+ memset(s->l1_table, 0, l1_size2);
+
+ BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE);
+
+ /* Overwrite enough clusters at the beginning of the sectors to place
+ * the refcount table, a refcount block and the L1 table in; this may
+ * overwrite parts of the existing refcount and L1 table, which is not
+ * an issue because the dirty flag is set, complete data loss is in fact
+ * desired and partial data loss is consequently fine as well */
+ ret = bdrv_write_zeroes(bs->file, s->cluster_size / BDRV_SECTOR_SIZE,
+ (2 + l1_clusters) * s->cluster_size /
+ BDRV_SECTOR_SIZE, 0);
+ /* This call (even if it failed overall) may have overwritten on-disk
+ * refcount structures; in that case, the in-memory refcount information
+ * will probably differ from the on-disk information which makes the BDS
+ * unusable */
+ if (ret < 0) {
+ goto fail_broken_refcounts;
+ }
+
+ BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
+ BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE);
+
+ /* "Create" an empty reftable (one cluster) directly after the image
+ * header and an empty L1 table three clusters after the image header;
+ * the cluster between those two will be used as the first refblock */
+ cpu_to_be64w(&l1_ofs_rt_ofs_cls.l1_offset, 3 * s->cluster_size);
+ cpu_to_be64w(&l1_ofs_rt_ofs_cls.reftable_offset, s->cluster_size);
+ cpu_to_be32w(&l1_ofs_rt_ofs_cls.reftable_clusters, 1);
+ ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset),
+ &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls));
+ if (ret < 0) {
+ goto fail_broken_refcounts;
+ }
+
+ s->l1_table_offset = 3 * s->cluster_size;
+
+ new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t));
+ if (!new_reftable) {
+ ret = -ENOMEM;
+ goto fail_broken_refcounts;
+ }
+
+ s->refcount_table_offset = s->cluster_size;
+ s->refcount_table_size = s->cluster_size / sizeof(uint64_t);
+
+ g_free(s->refcount_table);
+ s->refcount_table = new_reftable;
+ new_reftable = NULL;
+
+ /* Now the in-memory refcount information again corresponds to the on-disk
+ * information (reftable is empty and no refblocks (the refblock cache is
+ * empty)); however, this means some clusters (e.g. the image header) are
+ * referenced, but not refcounted, but the normal qcow2 code assumes that
+ * the in-memory information is always correct */
+
+ BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC);
+
+ /* Enter the first refblock into the reftable */
+ rt_entry = cpu_to_be64(2 * s->cluster_size);
+ ret = bdrv_pwrite_sync(bs->file, s->cluster_size,
+ &rt_entry, sizeof(rt_entry));
+ if (ret < 0) {
+ goto fail_broken_refcounts;
+ }
+ s->refcount_table[0] = 2 * s->cluster_size;
+
+ s->free_cluster_index = 0;
+ assert(3 + l1_clusters <= s->refcount_block_size);
+ offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2);
+ if (offset < 0) {
+ ret = offset;
+ goto fail_broken_refcounts;
+ } else if (offset > 0) {
+ error_report("First cluster in emptied image is in use");
+ abort();
+ }
+
+ /* Now finally the in-memory information corresponds to the on-disk
+ * structures and is correct */
+ ret = qcow2_mark_clean(bs);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ return 0;
+
+fail_broken_refcounts:
+ /* The BDS is unusable at this point. If we wanted to make it usable, we
+ * would have to call qcow2_refcount_close(), qcow2_refcount_init(),
+ * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init()
+ * again. However, because the functions which could have caused this error
+ * path to be taken are used by those functions as well, it's very likely
+ * that that sequence will fail as well. Therefore, just eject the BDS. */
+ bs->drv = NULL;
+
+fail:
+ g_free(new_reftable);
+ return ret;
+}
+
+static int qcow2_make_empty(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t start_sector;
+ int sector_step = INT_MAX / BDRV_SECTOR_SIZE;
+ int l1_clusters, ret = 0;
+
+ l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
+
+ if (s->qcow_version >= 3 && !s->snapshots &&
+ 3 + l1_clusters <= s->refcount_block_size) {
+ /* The following function only works for qcow2 v3 images (it requires
+ * the dirty flag) and only as long as there are no snapshots (because
+ * it completely empties the image). Furthermore, the L1 table and three
+ * additional clusters (image header, refcount table, one refcount
+ * block) have to fit inside one refcount block. */
+ return make_completely_empty(bs);
+ }
+
+ /* This fallback code simply discards every active cluster; this is slow,
+ * but works in all cases */
+ for (start_sector = 0; start_sector < bs->total_sectors;
+ start_sector += sector_step)
+ {
+ /* As this function is generally used after committing an external
+ * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the
+ * default action for this kind of discard is to pass the discard,
+ * which will ideally result in an actually smaller image file, as
+ * is probably desired. */
+ ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE,
+ MIN(sector_step,
+ bs->total_sectors - start_sector),
+ QCOW2_DISCARD_SNAPSHOT, true);
+ if (ret < 0) {
+ break;
+ }
+ }
+
+ return ret;
+}
+
+static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ int ret;
+
+ qemu_co_mutex_lock(&s->lock);
+ ret = qcow2_cache_flush(bs, s->l2_table_cache);
+ if (ret < 0) {
+ qemu_co_mutex_unlock(&s->lock);
+ return ret;
+ }
+
+ if (qcow2_need_accurate_refcounts(s)) {
+ ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+ if (ret < 0) {
+ qemu_co_mutex_unlock(&s->lock);
+ return ret;
+ }
+ }
+ qemu_co_mutex_unlock(&s->lock);
+
+ return 0;
+}
+
+static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
+{
+ BDRVQcowState *s = bs->opaque;
+ bdi->unallocated_blocks_are_zero = true;
+ bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3);
+ bdi->cluster_size = s->cluster_size;
+ bdi->vm_state_offset = qcow2_vm_state_offset(s);
+ return 0;
+}
+
+static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1);
+
+ *spec_info = (ImageInfoSpecific){
+ .kind = IMAGE_INFO_SPECIFIC_KIND_QCOW2,
+ {
+ .qcow2 = g_new(ImageInfoSpecificQCow2, 1),
+ },
+ };
+ if (s->qcow_version == 2) {
+ *spec_info->qcow2 = (ImageInfoSpecificQCow2){
+ .compat = g_strdup("0.10"),
+ .refcount_bits = s->refcount_bits,
+ };
+ } else if (s->qcow_version == 3) {
+ *spec_info->qcow2 = (ImageInfoSpecificQCow2){
+ .compat = g_strdup("1.1"),
+ .lazy_refcounts = s->compatible_features &
+ QCOW2_COMPAT_LAZY_REFCOUNTS,
+ .has_lazy_refcounts = true,
+ .corrupt = s->incompatible_features &
+ QCOW2_INCOMPAT_CORRUPT,
+ .has_corrupt = true,
+ .refcount_bits = s->refcount_bits,
+ };
+ }
+
+ return spec_info;
+}
+
+#if 0
+static void dump_refcounts(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ int64_t nb_clusters, k, k1, size;
+ int refcount;
+
+ size = bdrv_getlength(bs->file);
+ nb_clusters = size_to_clusters(s, size);
+ for(k = 0; k < nb_clusters;) {
+ k1 = k;
+ refcount = get_refcount(bs, k);
+ k++;
+ while (k < nb_clusters && get_refcount(bs, k) == refcount)
+ k++;
+ printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount,
+ k - k1);
+ }
+}
+#endif
+
+static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
+ int64_t pos)
+{
+ BDRVQcowState *s = bs->opaque;
+ int64_t total_sectors = bs->total_sectors;
+ bool zero_beyond_eof = bs->zero_beyond_eof;
+ int ret;
+
+ BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
+ bs->zero_beyond_eof = false;
+ ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov);
+ bs->zero_beyond_eof = zero_beyond_eof;
+
+ /* bdrv_co_do_writev will have increased the total_sectors value to include
+ * the VM state - the VM state is however not an actual part of the block
+ * device, therefore, we need to restore the old value. */
+ bs->total_sectors = total_sectors;
+
+ return ret;
+}
+
+static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf,
+ int64_t pos, int size)
+{
+ BDRVQcowState *s = bs->opaque;
+ bool zero_beyond_eof = bs->zero_beyond_eof;
+ int ret;
+
+ BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
+ bs->zero_beyond_eof = false;
+ ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size);
+ bs->zero_beyond_eof = zero_beyond_eof;
+
+ return ret;
+}
+
+/*
+ * Downgrades an image's version. To achieve this, any incompatible features
+ * have to be removed.
+ */
+static int qcow2_downgrade(BlockDriverState *bs, int target_version,
+ BlockDriverAmendStatusCB *status_cb)
+{
+ BDRVQcowState *s = bs->opaque;
+ int current_version = s->qcow_version;
+ int ret;
+
+ if (target_version == current_version) {
+ return 0;
+ } else if (target_version > current_version) {
+ return -EINVAL;
+ } else if (target_version != 2) {
+ return -EINVAL;
+ }
+
+ if (s->refcount_order != 4) {
+ /* we would have to convert the image to a refcount_order == 4 image
+ * here; however, since qemu (at the time of writing this) does not
+ * support anything different than 4 anyway, there is no point in doing
+ * so right now; however, we should error out (if qemu supports this in
+ * the future and this code has not been adapted) */
+ error_report("qcow2_downgrade: Image refcount orders other than 4 are "
+ "currently not supported.");
+ return -ENOTSUP;
+ }
+
+ /* clear incompatible features */
+ if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
+ ret = qcow2_mark_clean(bs);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in
+ * the first place; if that happens nonetheless, returning -ENOTSUP is the
+ * best thing to do anyway */
+
+ if (s->incompatible_features) {
+ return -ENOTSUP;
+ }
+
+ /* since we can ignore compatible features, we can set them to 0 as well */
+ s->compatible_features = 0;
+ /* if lazy refcounts have been used, they have already been fixed through
+ * clearing the dirty flag */
+
+ /* clearing autoclear features is trivial */
+ s->autoclear_features = 0;
+
+ ret = qcow2_expand_zero_clusters(bs, status_cb);
+ if (ret < 0) {
+ return ret;
+ }
+
+ s->qcow_version = target_version;
+ ret = qcow2_update_header(bs);
+ if (ret < 0) {
+ s->qcow_version = current_version;
+ return ret;
+ }
+ return 0;
+}
+
+static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
+ BlockDriverAmendStatusCB *status_cb)
+{
+ BDRVQcowState *s = bs->opaque;
+ int old_version = s->qcow_version, new_version = old_version;
+ uint64_t new_size = 0;
+ const char *backing_file = NULL, *backing_format = NULL;
+ bool lazy_refcounts = s->use_lazy_refcounts;
+ const char *compat = NULL;
+ uint64_t cluster_size = s->cluster_size;
+ bool encrypt;
+ int ret;
+ QemuOptDesc *desc = opts->list->desc;
+
+ while (desc && desc->name) {
+ if (!qemu_opt_find(opts, desc->name)) {
+ /* only change explicitly defined options */
+ desc++;
+ continue;
+ }
+
+ if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) {
+ compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL);
+ if (!compat) {
+ /* preserve default */
+ } else if (!strcmp(compat, "0.10")) {
+ new_version = 2;
+ } else if (!strcmp(compat, "1.1")) {
+ new_version = 3;
+ } else {
+ fprintf(stderr, "Unknown compatibility level %s.\n", compat);
+ return -EINVAL;
+ }
+ } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) {
+ fprintf(stderr, "Cannot change preallocation mode.\n");
+ return -ENOTSUP;
+ } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) {
+ new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
+ } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) {
+ backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
+ } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) {
+ backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
+ } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) {
+ encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT,
+ !!s->cipher);
+
+ if (encrypt != !!s->cipher) {
+ fprintf(stderr, "Changing the encryption flag is not "
+ "supported.\n");
+ return -ENOTSUP;
+ }
+ } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) {
+ cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE,
+ cluster_size);
+ if (cluster_size != s->cluster_size) {
+ fprintf(stderr, "Changing the cluster size is not "
+ "supported.\n");
+ return -ENOTSUP;
+ }
+ } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) {
+ lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS,
+ lazy_refcounts);
+ } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) {
+ error_report("Cannot change refcount entry width");
+ return -ENOTSUP;
+ } else {
+ /* if this assertion fails, this probably means a new option was
+ * added without having it covered here */
+ assert(false);
+ }
+
+ desc++;
+ }
+
+ if (new_version != old_version) {
+ if (new_version > old_version) {
+ /* Upgrade */
+ s->qcow_version = new_version;
+ ret = qcow2_update_header(bs);
+ if (ret < 0) {
+ s->qcow_version = old_version;
+ return ret;
+ }
+ } else {
+ ret = qcow2_downgrade(bs, new_version, status_cb);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+ }
+
+ if (backing_file || backing_format) {
+ ret = qcow2_change_backing_file(bs,
+ backing_file ?: s->image_backing_file,
+ backing_format ?: s->image_backing_format);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ if (s->use_lazy_refcounts != lazy_refcounts) {
+ if (lazy_refcounts) {
+ if (s->qcow_version < 3) {
+ fprintf(stderr, "Lazy refcounts only supported with compatibility "
+ "level 1.1 and above (use compat=1.1 or greater)\n");
+ return -EINVAL;
+ }
+ s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
+ ret = qcow2_update_header(bs);
+ if (ret < 0) {
+ s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
+ return ret;
+ }
+ s->use_lazy_refcounts = true;
+ } else {
+ /* make image clean first */
+ ret = qcow2_mark_clean(bs);
+ if (ret < 0) {
+ return ret;
+ }
+ /* now disallow lazy refcounts */
+ s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
+ ret = qcow2_update_header(bs);
+ if (ret < 0) {
+ s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
+ return ret;
+ }
+ s->use_lazy_refcounts = false;
+ }
+ }
+
+ if (new_size) {
+ ret = bdrv_truncate(bs, new_size);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * If offset or size are negative, respectively, they will not be included in
+ * the BLOCK_IMAGE_CORRUPTED event emitted.
+ * fatal will be ignored for read-only BDS; corruptions found there will always
+ * be considered non-fatal.
+ */
+void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
+ int64_t size, const char *message_format, ...)
+{
+ BDRVQcowState *s = bs->opaque;
+ const char *node_name;
+ char *message;
+ va_list ap;
+
+ fatal = fatal && !bs->read_only;
+
+ if (s->signaled_corruption &&
+ (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT)))
+ {
+ return;
+ }
+
+ va_start(ap, message_format);
+ message = g_strdup_vprintf(message_format, ap);
+ va_end(ap);
+
+ if (fatal) {
+ fprintf(stderr, "qcow2: Marking image as corrupt: %s; further "
+ "corruption events will be suppressed\n", message);
+ } else {
+ fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal "
+ "corruption events will be suppressed\n", message);
+ }
+
+ node_name = bdrv_get_node_name(bs);
+ qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs),
+ *node_name != '\0', node_name,
+ message, offset >= 0, offset,
+ size >= 0, size,
+ fatal, &error_abort);
+ g_free(message);
+
+ if (fatal) {
+ qcow2_mark_corrupt(bs);
+ bs->drv = NULL; /* make BDS unusable */
+ }
+
+ s->signaled_corruption = true;
+}
+
+static QemuOptsList qcow2_create_opts = {
+ .name = "qcow2-create-opts",
+ .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head),
+ .desc = {
+ {
+ .name = BLOCK_OPT_SIZE,
+ .type = QEMU_OPT_SIZE,
+ .help = "Virtual disk size"
+ },
+ {
+ .name = BLOCK_OPT_COMPAT_LEVEL,
+ .type = QEMU_OPT_STRING,
+ .help = "Compatibility level (0.10 or 1.1)"
+ },
+ {
+ .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_ENCRYPT,
+ .type = QEMU_OPT_BOOL,
+ .help = "Encrypt the image",
+ .def_value_str = "off"
+ },
+ {
+ .name = BLOCK_OPT_CLUSTER_SIZE,
+ .type = QEMU_OPT_SIZE,
+ .help = "qcow2 cluster size",
+ .def_value_str = stringify(DEFAULT_CLUSTER_SIZE)
+ },
+ {
+ .name = BLOCK_OPT_PREALLOC,
+ .type = QEMU_OPT_STRING,
+ .help = "Preallocation mode (allowed values: off, metadata, "
+ "falloc, full)"
+ },
+ {
+ .name = BLOCK_OPT_LAZY_REFCOUNTS,
+ .type = QEMU_OPT_BOOL,
+ .help = "Postpone refcount updates",
+ .def_value_str = "off"
+ },
+ {
+ .name = BLOCK_OPT_REFCOUNT_BITS,
+ .type = QEMU_OPT_NUMBER,
+ .help = "Width of a reference count entry in bits",
+ .def_value_str = "16"
+ },
+ { /* end of list */ }
+ }
+};
+
+BlockDriver bdrv_qcow2 = {
+ .format_name = "qcow2",
+ .instance_size = sizeof(BDRVQcowState),
+ .bdrv_probe = qcow2_probe,
+ .bdrv_open = qcow2_open,
+ .bdrv_close = qcow2_close,
+ .bdrv_reopen_prepare = qcow2_reopen_prepare,
+ .bdrv_create = qcow2_create,
+ .bdrv_has_zero_init = bdrv_has_zero_init_1,
+ .bdrv_co_get_block_status = qcow2_co_get_block_status,
+ .bdrv_set_key = qcow2_set_key,
+
+ .bdrv_co_readv = qcow2_co_readv,
+ .bdrv_co_writev = qcow2_co_writev,
+ .bdrv_co_flush_to_os = qcow2_co_flush_to_os,
+
+ .bdrv_co_write_zeroes = qcow2_co_write_zeroes,
+ .bdrv_co_discard = qcow2_co_discard,
+ .bdrv_truncate = qcow2_truncate,
+ .bdrv_write_compressed = qcow2_write_compressed,
+ .bdrv_make_empty = qcow2_make_empty,
+
+ .bdrv_snapshot_create = qcow2_snapshot_create,
+ .bdrv_snapshot_goto = qcow2_snapshot_goto,
+ .bdrv_snapshot_delete = qcow2_snapshot_delete,
+ .bdrv_snapshot_list = qcow2_snapshot_list,
+ .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp,
+ .bdrv_get_info = qcow2_get_info,
+ .bdrv_get_specific_info = qcow2_get_specific_info,
+
+ .bdrv_save_vmstate = qcow2_save_vmstate,
+ .bdrv_load_vmstate = qcow2_load_vmstate,
+
+ .supports_backing = true,
+ .bdrv_change_backing_file = qcow2_change_backing_file,
+
+ .bdrv_refresh_limits = qcow2_refresh_limits,
+ .bdrv_invalidate_cache = qcow2_invalidate_cache,
+
+ .create_opts = &qcow2_create_opts,
+ .bdrv_check = qcow2_check,
+ .bdrv_amend_options = qcow2_amend_options,
+};
+
+static void bdrv_qcow2_init(void)
+{
+ bdrv_register(&bdrv_qcow2);
+}
+
+block_init(bdrv_qcow2_init);
Code Review / kvmfornfv.git / blobdiff