--- /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 <zlib.h>
+
+#include "qemu-common.h"
+#include "block/block_int.h"
+#include "block/qcow2.h"
+#include "trace.h"
+
+int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
+ bool exact_size)
+{
+ BDRVQcowState *s = bs->opaque;
+ int new_l1_size2, ret, i;
+ uint64_t *new_l1_table;
+ int64_t old_l1_table_offset, old_l1_size;
+ int64_t new_l1_table_offset, new_l1_size;
+ uint8_t data[12];
+
+ if (min_size <= s->l1_size)
+ return 0;
+
+ /* Do a sanity check on min_size before trying to calculate new_l1_size
+ * (this prevents overflows during the while loop for the calculation of
+ * new_l1_size) */
+ if (min_size > INT_MAX / sizeof(uint64_t)) {
+ return -EFBIG;
+ }
+
+ if (exact_size) {
+ new_l1_size = min_size;
+ } else {
+ /* Bump size up to reduce the number of times we have to grow */
+ new_l1_size = s->l1_size;
+ if (new_l1_size == 0) {
+ new_l1_size = 1;
+ }
+ while (min_size > new_l1_size) {
+ new_l1_size = (new_l1_size * 3 + 1) / 2;
+ }
+ }
+
+ if (new_l1_size > INT_MAX / sizeof(uint64_t)) {
+ return -EFBIG;
+ }
+
+#ifdef DEBUG_ALLOC2
+ fprintf(stderr, "grow l1_table from %d to %" PRId64 "\n",
+ s->l1_size, new_l1_size);
+#endif
+
+ new_l1_size2 = sizeof(uint64_t) * new_l1_size;
+ new_l1_table = qemu_try_blockalign(bs->file,
+ align_offset(new_l1_size2, 512));
+ if (new_l1_table == NULL) {
+ return -ENOMEM;
+ }
+ memset(new_l1_table, 0, align_offset(new_l1_size2, 512));
+
+ memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
+
+ /* write new table (align to cluster) */
+ BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE);
+ new_l1_table_offset = qcow2_alloc_clusters(bs, new_l1_size2);
+ if (new_l1_table_offset < 0) {
+ qemu_vfree(new_l1_table);
+ return new_l1_table_offset;
+ }
+
+ ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ /* the L1 position has not yet been updated, so these clusters must
+ * indeed be completely free */
+ ret = qcow2_pre_write_overlap_check(bs, 0, new_l1_table_offset,
+ new_l1_size2);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE);
+ for(i = 0; i < s->l1_size; i++)
+ new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
+ ret = bdrv_pwrite_sync(bs->file, new_l1_table_offset, new_l1_table, new_l1_size2);
+ if (ret < 0)
+ goto fail;
+ for(i = 0; i < s->l1_size; i++)
+ new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
+
+ /* set new table */
+ BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ACTIVATE_TABLE);
+ cpu_to_be32w((uint32_t*)data, new_l1_size);
+ stq_be_p(data + 4, new_l1_table_offset);
+ ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_size), data,sizeof(data));
+ if (ret < 0) {
+ goto fail;
+ }
+ qemu_vfree(s->l1_table);
+ old_l1_table_offset = s->l1_table_offset;
+ s->l1_table_offset = new_l1_table_offset;
+ s->l1_table = new_l1_table;
+ old_l1_size = s->l1_size;
+ s->l1_size = new_l1_size;
+ qcow2_free_clusters(bs, old_l1_table_offset, old_l1_size * sizeof(uint64_t),
+ QCOW2_DISCARD_OTHER);
+ return 0;
+ fail:
+ qemu_vfree(new_l1_table);
+ qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2,
+ QCOW2_DISCARD_OTHER);
+ return ret;
+}
+
+/*
+ * l2_load
+ *
+ * Loads a L2 table into memory. If the table is in the cache, the cache
+ * is used; otherwise the L2 table is loaded from the image file.
+ *
+ * Returns a pointer to the L2 table on success, or NULL if the read from
+ * the image file failed.
+ */
+
+static int l2_load(BlockDriverState *bs, uint64_t l2_offset,
+ uint64_t **l2_table)
+{
+ BDRVQcowState *s = bs->opaque;
+ int ret;
+
+ ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, (void**) l2_table);
+
+ return ret;
+}
+
+/*
+ * Writes one sector of the L1 table to the disk (can't update single entries
+ * and we really don't want bdrv_pread to perform a read-modify-write)
+ */
+#define L1_ENTRIES_PER_SECTOR (512 / 8)
+int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t buf[L1_ENTRIES_PER_SECTOR] = { 0 };
+ int l1_start_index;
+ int i, ret;
+
+ l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1);
+ for (i = 0; i < L1_ENTRIES_PER_SECTOR && l1_start_index + i < s->l1_size;
+ i++)
+ {
+ buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
+ }
+
+ ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
+ s->l1_table_offset + 8 * l1_start_index, sizeof(buf));
+ if (ret < 0) {
+ return ret;
+ }
+
+ BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
+ ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset + 8 * l1_start_index,
+ buf, sizeof(buf));
+ if (ret < 0) {
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * l2_allocate
+ *
+ * Allocate a new l2 entry in the file. If l1_index points to an already
+ * used entry in the L2 table (i.e. we are doing a copy on write for the L2
+ * table) copy the contents of the old L2 table into the newly allocated one.
+ * Otherwise the new table is initialized with zeros.
+ *
+ */
+
+static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t old_l2_offset;
+ uint64_t *l2_table = NULL;
+ int64_t l2_offset;
+ int ret;
+
+ old_l2_offset = s->l1_table[l1_index];
+
+ trace_qcow2_l2_allocate(bs, l1_index);
+
+ /* allocate a new l2 entry */
+
+ l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
+ if (l2_offset < 0) {
+ ret = l2_offset;
+ goto fail;
+ }
+
+ ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ /* allocate a new entry in the l2 cache */
+
+ trace_qcow2_l2_allocate_get_empty(bs, l1_index);
+ ret = qcow2_cache_get_empty(bs, s->l2_table_cache, l2_offset, (void**) table);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ l2_table = *table;
+
+ if ((old_l2_offset & L1E_OFFSET_MASK) == 0) {
+ /* if there was no old l2 table, clear the new table */
+ memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
+ } else {
+ uint64_t* old_table;
+
+ /* if there was an old l2 table, read it from the disk */
+ BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ);
+ ret = qcow2_cache_get(bs, s->l2_table_cache,
+ old_l2_offset & L1E_OFFSET_MASK,
+ (void**) &old_table);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ memcpy(l2_table, old_table, s->cluster_size);
+
+ qcow2_cache_put(bs, s->l2_table_cache, (void **) &old_table);
+ }
+
+ /* write the l2 table to the file */
+ BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE);
+
+ trace_qcow2_l2_allocate_write_l2(bs, l1_index);
+ qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table);
+ ret = qcow2_cache_flush(bs, s->l2_table_cache);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ /* update the L1 entry */
+ trace_qcow2_l2_allocate_write_l1(bs, l1_index);
+ s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
+ ret = qcow2_write_l1_entry(bs, l1_index);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ *table = l2_table;
+ trace_qcow2_l2_allocate_done(bs, l1_index, 0);
+ return 0;
+
+fail:
+ trace_qcow2_l2_allocate_done(bs, l1_index, ret);
+ if (l2_table != NULL) {
+ qcow2_cache_put(bs, s->l2_table_cache, (void**) table);
+ }
+ s->l1_table[l1_index] = old_l2_offset;
+ if (l2_offset > 0) {
+ qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t),
+ QCOW2_DISCARD_ALWAYS);
+ }
+ return ret;
+}
+
+/*
+ * Checks how many clusters in a given L2 table are contiguous in the image
+ * file. As soon as one of the flags in the bitmask stop_flags changes compared
+ * to the first cluster, the search is stopped and the cluster is not counted
+ * as contiguous. (This allows it, for example, to stop at the first compressed
+ * cluster which may require a different handling)
+ */
+static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size,
+ uint64_t *l2_table, uint64_t stop_flags)
+{
+ int i;
+ uint64_t mask = stop_flags | L2E_OFFSET_MASK | QCOW_OFLAG_COMPRESSED;
+ uint64_t first_entry = be64_to_cpu(l2_table[0]);
+ uint64_t offset = first_entry & mask;
+
+ if (!offset)
+ return 0;
+
+ assert(qcow2_get_cluster_type(first_entry) != QCOW2_CLUSTER_COMPRESSED);
+
+ for (i = 0; i < nb_clusters; i++) {
+ uint64_t l2_entry = be64_to_cpu(l2_table[i]) & mask;
+ if (offset + (uint64_t) i * cluster_size != l2_entry) {
+ break;
+ }
+ }
+
+ return i;
+}
+
+static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table)
+{
+ int i;
+
+ for (i = 0; i < nb_clusters; i++) {
+ int type = qcow2_get_cluster_type(be64_to_cpu(l2_table[i]));
+
+ if (type != QCOW2_CLUSTER_UNALLOCATED) {
+ break;
+ }
+ }
+
+ return i;
+}
+
+/* The crypt function is compatible with the linux cryptoloop
+ algorithm for < 4 GB images. NOTE: out_buf == in_buf is
+ supported */
+int qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
+ uint8_t *out_buf, const uint8_t *in_buf,
+ int nb_sectors, bool enc,
+ Error **errp)
+{
+ union {
+ uint64_t ll[2];
+ uint8_t b[16];
+ } ivec;
+ int i;
+ int ret;
+
+ for(i = 0; i < nb_sectors; i++) {
+ ivec.ll[0] = cpu_to_le64(sector_num);
+ ivec.ll[1] = 0;
+ if (qcrypto_cipher_setiv(s->cipher,
+ ivec.b, G_N_ELEMENTS(ivec.b),
+ errp) < 0) {
+ return -1;
+ }
+ if (enc) {
+ ret = qcrypto_cipher_encrypt(s->cipher,
+ in_buf,
+ out_buf,
+ 512,
+ errp);
+ } else {
+ ret = qcrypto_cipher_decrypt(s->cipher,
+ in_buf,
+ out_buf,
+ 512,
+ errp);
+ }
+ if (ret < 0) {
+ return -1;
+ }
+ sector_num++;
+ in_buf += 512;
+ out_buf += 512;
+ }
+ return 0;
+}
+
+static int coroutine_fn copy_sectors(BlockDriverState *bs,
+ uint64_t start_sect,
+ uint64_t cluster_offset,
+ int n_start, int n_end)
+{
+ BDRVQcowState *s = bs->opaque;
+ QEMUIOVector qiov;
+ struct iovec iov;
+ int n, ret;
+
+ n = n_end - n_start;
+ if (n <= 0) {
+ return 0;
+ }
+
+ iov.iov_len = n * BDRV_SECTOR_SIZE;
+ iov.iov_base = qemu_try_blockalign(bs, iov.iov_len);
+ if (iov.iov_base == NULL) {
+ return -ENOMEM;
+ }
+
+ qemu_iovec_init_external(&qiov, &iov, 1);
+
+ BLKDBG_EVENT(bs->file, BLKDBG_COW_READ);
+
+ if (!bs->drv) {
+ ret = -ENOMEDIUM;
+ goto out;
+ }
+
+ /* Call .bdrv_co_readv() directly instead of using the public block-layer
+ * interface. This avoids double I/O throttling and request tracking,
+ * which can lead to deadlock when block layer copy-on-read is enabled.
+ */
+ ret = bs->drv->bdrv_co_readv(bs, start_sect + n_start, n, &qiov);
+ if (ret < 0) {
+ goto out;
+ }
+
+ if (bs->encrypted) {
+ Error *err = NULL;
+ assert(s->cipher);
+ if (qcow2_encrypt_sectors(s, start_sect + n_start,
+ iov.iov_base, iov.iov_base, n,
+ true, &err) < 0) {
+ ret = -EIO;
+ error_free(err);
+ goto out;
+ }
+ }
+
+ ret = qcow2_pre_write_overlap_check(bs, 0,
+ cluster_offset + n_start * BDRV_SECTOR_SIZE, n * BDRV_SECTOR_SIZE);
+ if (ret < 0) {
+ goto out;
+ }
+
+ BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
+ ret = bdrv_co_writev(bs->file, (cluster_offset >> 9) + n_start, n, &qiov);
+ if (ret < 0) {
+ goto out;
+ }
+
+ ret = 0;
+out:
+ qemu_vfree(iov.iov_base);
+ return ret;
+}
+
+
+/*
+ * get_cluster_offset
+ *
+ * For a given offset of the disk image, find the cluster offset in
+ * qcow2 file. The offset is stored in *cluster_offset.
+ *
+ * on entry, *num is the number of contiguous sectors we'd like to
+ * access following offset.
+ *
+ * on exit, *num is the number of contiguous sectors we can read.
+ *
+ * Returns the cluster type (QCOW2_CLUSTER_*) on success, -errno in error
+ * cases.
+ */
+int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
+ int *num, uint64_t *cluster_offset)
+{
+ BDRVQcowState *s = bs->opaque;
+ unsigned int l2_index;
+ uint64_t l1_index, l2_offset, *l2_table;
+ int l1_bits, c;
+ unsigned int index_in_cluster, nb_clusters;
+ uint64_t nb_available, nb_needed;
+ int ret;
+
+ index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1);
+ nb_needed = *num + index_in_cluster;
+
+ l1_bits = s->l2_bits + s->cluster_bits;
+
+ /* compute how many bytes there are between the offset and
+ * the end of the l1 entry
+ */
+
+ nb_available = (1ULL << l1_bits) - (offset & ((1ULL << l1_bits) - 1));
+
+ /* compute the number of available sectors */
+
+ nb_available = (nb_available >> 9) + index_in_cluster;
+
+ if (nb_needed > nb_available) {
+ nb_needed = nb_available;
+ }
+
+ *cluster_offset = 0;
+
+ /* seek the the l2 offset in the l1 table */
+
+ l1_index = offset >> l1_bits;
+ if (l1_index >= s->l1_size) {
+ ret = QCOW2_CLUSTER_UNALLOCATED;
+ goto out;
+ }
+
+ l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
+ if (!l2_offset) {
+ ret = QCOW2_CLUSTER_UNALLOCATED;
+ goto out;
+ }
+
+ if (offset_into_cluster(s, l2_offset)) {
+ qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#" PRIx64
+ " unaligned (L1 index: %#" PRIx64 ")",
+ l2_offset, l1_index);
+ return -EIO;
+ }
+
+ /* load the l2 table in memory */
+
+ ret = l2_load(bs, l2_offset, &l2_table);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* find the cluster offset for the given disk offset */
+
+ l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
+ *cluster_offset = be64_to_cpu(l2_table[l2_index]);
+ nb_clusters = size_to_clusters(s, nb_needed << 9);
+
+ ret = qcow2_get_cluster_type(*cluster_offset);
+ switch (ret) {
+ case QCOW2_CLUSTER_COMPRESSED:
+ /* Compressed clusters can only be processed one by one */
+ c = 1;
+ *cluster_offset &= L2E_COMPRESSED_OFFSET_SIZE_MASK;
+ break;
+ case QCOW2_CLUSTER_ZERO:
+ if (s->qcow_version < 3) {
+ qcow2_signal_corruption(bs, true, -1, -1, "Zero cluster entry found"
+ " in pre-v3 image (L2 offset: %#" PRIx64
+ ", L2 index: %#x)", l2_offset, l2_index);
+ ret = -EIO;
+ goto fail;
+ }
+ c = count_contiguous_clusters(nb_clusters, s->cluster_size,
+ &l2_table[l2_index], QCOW_OFLAG_ZERO);
+ *cluster_offset = 0;
+ break;
+ case QCOW2_CLUSTER_UNALLOCATED:
+ /* how many empty clusters ? */
+ c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]);
+ *cluster_offset = 0;
+ break;
+ case QCOW2_CLUSTER_NORMAL:
+ /* how many allocated clusters ? */
+ c = count_contiguous_clusters(nb_clusters, s->cluster_size,
+ &l2_table[l2_index], QCOW_OFLAG_ZERO);
+ *cluster_offset &= L2E_OFFSET_MASK;
+ if (offset_into_cluster(s, *cluster_offset)) {
+ qcow2_signal_corruption(bs, true, -1, -1, "Data cluster offset %#"
+ PRIx64 " unaligned (L2 offset: %#" PRIx64
+ ", L2 index: %#x)", *cluster_offset,
+ l2_offset, l2_index);
+ ret = -EIO;
+ goto fail;
+ }
+ break;
+ default:
+ abort();
+ }
+
+ qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+
+ nb_available = (c * s->cluster_sectors);
+
+out:
+ if (nb_available > nb_needed)
+ nb_available = nb_needed;
+
+ *num = nb_available - index_in_cluster;
+
+ return ret;
+
+fail:
+ qcow2_cache_put(bs, s->l2_table_cache, (void **)&l2_table);
+ return ret;
+}
+
+/*
+ * get_cluster_table
+ *
+ * for a given disk offset, load (and allocate if needed)
+ * the l2 table.
+ *
+ * the l2 table offset in the qcow2 file and the cluster index
+ * in the l2 table are given to the caller.
+ *
+ * Returns 0 on success, -errno in failure case
+ */
+static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
+ uint64_t **new_l2_table,
+ int *new_l2_index)
+{
+ BDRVQcowState *s = bs->opaque;
+ unsigned int l2_index;
+ uint64_t l1_index, l2_offset;
+ uint64_t *l2_table = NULL;
+ int ret;
+
+ /* seek the the l2 offset in the l1 table */
+
+ l1_index = offset >> (s->l2_bits + s->cluster_bits);
+ if (l1_index >= s->l1_size) {
+ ret = qcow2_grow_l1_table(bs, l1_index + 1, false);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ assert(l1_index < s->l1_size);
+ l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
+ if (offset_into_cluster(s, l2_offset)) {
+ qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#" PRIx64
+ " unaligned (L1 index: %#" PRIx64 ")",
+ l2_offset, l1_index);
+ return -EIO;
+ }
+
+ /* seek the l2 table of the given l2 offset */
+
+ if (s->l1_table[l1_index] & QCOW_OFLAG_COPIED) {
+ /* load the l2 table in memory */
+ ret = l2_load(bs, l2_offset, &l2_table);
+ if (ret < 0) {
+ return ret;
+ }
+ } else {
+ /* First allocate a new L2 table (and do COW if needed) */
+ ret = l2_allocate(bs, l1_index, &l2_table);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* Then decrease the refcount of the old table */
+ if (l2_offset) {
+ qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t),
+ QCOW2_DISCARD_OTHER);
+ }
+ }
+
+ /* find the cluster offset for the given disk offset */
+
+ l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
+
+ *new_l2_table = l2_table;
+ *new_l2_index = l2_index;
+
+ return 0;
+}
+
+/*
+ * alloc_compressed_cluster_offset
+ *
+ * For a given offset of the disk image, return cluster offset in
+ * qcow2 file.
+ *
+ * If the offset is not found, allocate a new compressed cluster.
+ *
+ * Return the cluster offset if successful,
+ * Return 0, otherwise.
+ *
+ */
+
+uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
+ uint64_t offset,
+ int compressed_size)
+{
+ BDRVQcowState *s = bs->opaque;
+ int l2_index, ret;
+ uint64_t *l2_table;
+ int64_t cluster_offset;
+ int nb_csectors;
+
+ ret = get_cluster_table(bs, offset, &l2_table, &l2_index);
+ if (ret < 0) {
+ return 0;
+ }
+
+ /* Compression can't overwrite anything. Fail if the cluster was already
+ * allocated. */
+ cluster_offset = be64_to_cpu(l2_table[l2_index]);
+ if (cluster_offset & L2E_OFFSET_MASK) {
+ qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+ return 0;
+ }
+
+ cluster_offset = qcow2_alloc_bytes(bs, compressed_size);
+ if (cluster_offset < 0) {
+ qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+ return 0;
+ }
+
+ nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
+ (cluster_offset >> 9);
+
+ cluster_offset |= QCOW_OFLAG_COMPRESSED |
+ ((uint64_t)nb_csectors << s->csize_shift);
+
+ /* update L2 table */
+
+ /* compressed clusters never have the copied flag */
+
+ BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
+ qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table);
+ l2_table[l2_index] = cpu_to_be64(cluster_offset);
+ qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
+
+ return cluster_offset;
+}
+
+static int perform_cow(BlockDriverState *bs, QCowL2Meta *m, Qcow2COWRegion *r)
+{
+ BDRVQcowState *s = bs->opaque;
+ int ret;
+
+ if (r->nb_sectors == 0) {
+ return 0;
+ }
+
+ qemu_co_mutex_unlock(&s->lock);
+ ret = copy_sectors(bs, m->offset / BDRV_SECTOR_SIZE, m->alloc_offset,
+ r->offset / BDRV_SECTOR_SIZE,
+ r->offset / BDRV_SECTOR_SIZE + r->nb_sectors);
+ qemu_co_mutex_lock(&s->lock);
+
+ if (ret < 0) {
+ return ret;
+ }
+
+ /*
+ * Before we update the L2 table to actually point to the new cluster, we
+ * need to be sure that the refcounts have been increased and COW was
+ * handled.
+ */
+ qcow2_cache_depends_on_flush(s->l2_table_cache);
+
+ return 0;
+}
+
+int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
+{
+ BDRVQcowState *s = bs->opaque;
+ int i, j = 0, l2_index, ret;
+ uint64_t *old_cluster, *l2_table;
+ uint64_t cluster_offset = m->alloc_offset;
+
+ trace_qcow2_cluster_link_l2(qemu_coroutine_self(), m->nb_clusters);
+ assert(m->nb_clusters > 0);
+
+ old_cluster = g_try_new(uint64_t, m->nb_clusters);
+ if (old_cluster == NULL) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ /* copy content of unmodified sectors */
+ ret = perform_cow(bs, m, &m->cow_start);
+ if (ret < 0) {
+ goto err;
+ }
+
+ ret = perform_cow(bs, m, &m->cow_end);
+ if (ret < 0) {
+ goto err;
+ }
+
+ /* Update L2 table. */
+ if (s->use_lazy_refcounts) {
+ qcow2_mark_dirty(bs);
+ }
+ if (qcow2_need_accurate_refcounts(s)) {
+ qcow2_cache_set_dependency(bs, s->l2_table_cache,
+ s->refcount_block_cache);
+ }
+
+ ret = get_cluster_table(bs, m->offset, &l2_table, &l2_index);
+ if (ret < 0) {
+ goto err;
+ }
+ qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table);
+
+ assert(l2_index + m->nb_clusters <= s->l2_size);
+ for (i = 0; i < m->nb_clusters; i++) {
+ /* if two concurrent writes happen to the same unallocated cluster
+ * each write allocates separate cluster and writes data concurrently.
+ * The first one to complete updates l2 table with pointer to its
+ * cluster the second one has to do RMW (which is done above by
+ * copy_sectors()), update l2 table with its cluster pointer and free
+ * old cluster. This is what this loop does */
+ if(l2_table[l2_index + i] != 0)
+ old_cluster[j++] = l2_table[l2_index + i];
+
+ l2_table[l2_index + i] = cpu_to_be64((cluster_offset +
+ (i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
+ }
+
+
+ qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
+
+ /*
+ * If this was a COW, we need to decrease the refcount of the old cluster.
+ * Also flush bs->file to get the right order for L2 and refcount update.
+ *
+ * Don't discard clusters that reach a refcount of 0 (e.g. compressed
+ * clusters), the next write will reuse them anyway.
+ */
+ if (j != 0) {
+ for (i = 0; i < j; i++) {
+ qcow2_free_any_clusters(bs, be64_to_cpu(old_cluster[i]), 1,
+ QCOW2_DISCARD_NEVER);
+ }
+ }
+
+ ret = 0;
+err:
+ g_free(old_cluster);
+ return ret;
+ }
+
+/*
+ * Returns the number of contiguous clusters that can be used for an allocating
+ * write, but require COW to be performed (this includes yet unallocated space,
+ * which must copy from the backing file)
+ */
+static int count_cow_clusters(BDRVQcowState *s, int nb_clusters,
+ uint64_t *l2_table, int l2_index)
+{
+ int i;
+
+ for (i = 0; i < nb_clusters; i++) {
+ uint64_t l2_entry = be64_to_cpu(l2_table[l2_index + i]);
+ int cluster_type = qcow2_get_cluster_type(l2_entry);
+
+ switch(cluster_type) {
+ case QCOW2_CLUSTER_NORMAL:
+ if (l2_entry & QCOW_OFLAG_COPIED) {
+ goto out;
+ }
+ break;
+ case QCOW2_CLUSTER_UNALLOCATED:
+ case QCOW2_CLUSTER_COMPRESSED:
+ case QCOW2_CLUSTER_ZERO:
+ break;
+ default:
+ abort();
+ }
+ }
+
+out:
+ assert(i <= nb_clusters);
+ return i;
+}
+
+/*
+ * Check if there already is an AIO write request in flight which allocates
+ * the same cluster. In this case we need to wait until the previous
+ * request has completed and updated the L2 table accordingly.
+ *
+ * Returns:
+ * 0 if there was no dependency. *cur_bytes indicates the number of
+ * bytes from guest_offset that can be read before the next
+ * dependency must be processed (or the request is complete)
+ *
+ * -EAGAIN if we had to wait for another request, previously gathered
+ * information on cluster allocation may be invalid now. The caller
+ * must start over anyway, so consider *cur_bytes undefined.
+ */
+static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset,
+ uint64_t *cur_bytes, QCowL2Meta **m)
+{
+ BDRVQcowState *s = bs->opaque;
+ QCowL2Meta *old_alloc;
+ uint64_t bytes = *cur_bytes;
+
+ QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) {
+
+ uint64_t start = guest_offset;
+ uint64_t end = start + bytes;
+ uint64_t old_start = l2meta_cow_start(old_alloc);
+ uint64_t old_end = l2meta_cow_end(old_alloc);
+
+ if (end <= old_start || start >= old_end) {
+ /* No intersection */
+ } else {
+ if (start < old_start) {
+ /* Stop at the start of a running allocation */
+ bytes = old_start - start;
+ } else {
+ bytes = 0;
+ }
+
+ /* Stop if already an l2meta exists. After yielding, it wouldn't
+ * be valid any more, so we'd have to clean up the old L2Metas
+ * and deal with requests depending on them before starting to
+ * gather new ones. Not worth the trouble. */
+ if (bytes == 0 && *m) {
+ *cur_bytes = 0;
+ return 0;
+ }
+
+ if (bytes == 0) {
+ /* Wait for the dependency to complete. We need to recheck
+ * the free/allocated clusters when we continue. */
+ qemu_co_mutex_unlock(&s->lock);
+ qemu_co_queue_wait(&old_alloc->dependent_requests);
+ qemu_co_mutex_lock(&s->lock);
+ return -EAGAIN;
+ }
+ }
+ }
+
+ /* Make sure that existing clusters and new allocations are only used up to
+ * the next dependency if we shortened the request above */
+ *cur_bytes = bytes;
+
+ return 0;
+}
+
+/*
+ * Checks how many already allocated clusters that don't require a copy on
+ * write there are at the given guest_offset (up to *bytes). If
+ * *host_offset is not zero, only physically contiguous clusters beginning at
+ * this host offset are counted.
+ *
+ * Note that guest_offset may not be cluster aligned. In this case, the
+ * returned *host_offset points to exact byte referenced by guest_offset and
+ * therefore isn't cluster aligned as well.
+ *
+ * Returns:
+ * 0: if no allocated clusters are available at the given offset.
+ * *bytes is normally unchanged. It is set to 0 if the cluster
+ * is allocated and doesn't need COW, but doesn't have the right
+ * physical offset.
+ *
+ * 1: if allocated clusters that don't require a COW are available at
+ * the requested offset. *bytes may have decreased and describes
+ * the length of the area that can be written to.
+ *
+ * -errno: in error cases
+ */
+static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,
+ uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m)
+{
+ BDRVQcowState *s = bs->opaque;
+ int l2_index;
+ uint64_t cluster_offset;
+ uint64_t *l2_table;
+ unsigned int nb_clusters;
+ unsigned int keep_clusters;
+ int ret;
+
+ trace_qcow2_handle_copied(qemu_coroutine_self(), guest_offset, *host_offset,
+ *bytes);
+
+ assert(*host_offset == 0 || offset_into_cluster(s, guest_offset)
+ == offset_into_cluster(s, *host_offset));
+
+ /*
+ * Calculate the number of clusters to look for. We stop at L2 table
+ * boundaries to keep things simple.
+ */
+ nb_clusters =
+ size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes);
+
+ l2_index = offset_to_l2_index(s, guest_offset);
+ nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
+
+ /* Find L2 entry for the first involved cluster */
+ ret = get_cluster_table(bs, guest_offset, &l2_table, &l2_index);
+ if (ret < 0) {
+ return ret;
+ }
+
+ cluster_offset = be64_to_cpu(l2_table[l2_index]);
+
+ /* Check how many clusters are already allocated and don't need COW */
+ if (qcow2_get_cluster_type(cluster_offset) == QCOW2_CLUSTER_NORMAL
+ && (cluster_offset & QCOW_OFLAG_COPIED))
+ {
+ /* If a specific host_offset is required, check it */
+ bool offset_matches =
+ (cluster_offset & L2E_OFFSET_MASK) == *host_offset;
+
+ if (offset_into_cluster(s, cluster_offset & L2E_OFFSET_MASK)) {
+ qcow2_signal_corruption(bs, true, -1, -1, "Data cluster offset "
+ "%#llx unaligned (guest offset: %#" PRIx64
+ ")", cluster_offset & L2E_OFFSET_MASK,
+ guest_offset);
+ ret = -EIO;
+ goto out;
+ }
+
+ if (*host_offset != 0 && !offset_matches) {
+ *bytes = 0;
+ ret = 0;
+ goto out;
+ }
+
+ /* We keep all QCOW_OFLAG_COPIED clusters */
+ keep_clusters =
+ count_contiguous_clusters(nb_clusters, s->cluster_size,
+ &l2_table[l2_index],
+ QCOW_OFLAG_COPIED | QCOW_OFLAG_ZERO);
+ assert(keep_clusters <= nb_clusters);
+
+ *bytes = MIN(*bytes,
+ keep_clusters * s->cluster_size
+ - offset_into_cluster(s, guest_offset));
+
+ ret = 1;
+ } else {
+ ret = 0;
+ }
+
+ /* Cleanup */
+out:
+ qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
+
+ /* Only return a host offset if we actually made progress. Otherwise we
+ * would make requirements for handle_alloc() that it can't fulfill */
+ if (ret > 0) {
+ *host_offset = (cluster_offset & L2E_OFFSET_MASK)
+ + offset_into_cluster(s, guest_offset);
+ }
+
+ return ret;
+}
+
+/*
+ * Allocates new clusters for the given guest_offset.
+ *
+ * At most *nb_clusters are allocated, and on return *nb_clusters is updated to
+ * contain the number of clusters that have been allocated and are contiguous
+ * in the image file.
+ *
+ * If *host_offset is non-zero, it specifies the offset in the image file at
+ * which the new clusters must start. *nb_clusters can be 0 on return in this
+ * case if the cluster at host_offset is already in use. If *host_offset is
+ * zero, the clusters can be allocated anywhere in the image file.
+ *
+ * *host_offset is updated to contain the offset into the image file at which
+ * the first allocated cluster starts.
+ *
+ * Return 0 on success and -errno in error cases. -EAGAIN means that the
+ * function has been waiting for another request and the allocation must be
+ * restarted, but the whole request should not be failed.
+ */
+static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
+ uint64_t *host_offset, unsigned int *nb_clusters)
+{
+ BDRVQcowState *s = bs->opaque;
+
+ trace_qcow2_do_alloc_clusters_offset(qemu_coroutine_self(), guest_offset,
+ *host_offset, *nb_clusters);
+
+ /* Allocate new clusters */
+ trace_qcow2_cluster_alloc_phys(qemu_coroutine_self());
+ if (*host_offset == 0) {
+ int64_t cluster_offset =
+ qcow2_alloc_clusters(bs, *nb_clusters * s->cluster_size);
+ if (cluster_offset < 0) {
+ return cluster_offset;
+ }
+ *host_offset = cluster_offset;
+ return 0;
+ } else {
+ int ret = qcow2_alloc_clusters_at(bs, *host_offset, *nb_clusters);
+ if (ret < 0) {
+ return ret;
+ }
+ *nb_clusters = ret;
+ return 0;
+ }
+}
+
+/*
+ * Allocates new clusters for an area that either is yet unallocated or needs a
+ * copy on write. If *host_offset is non-zero, clusters are only allocated if
+ * the new allocation can match the specified host offset.
+ *
+ * Note that guest_offset may not be cluster aligned. In this case, the
+ * returned *host_offset points to exact byte referenced by guest_offset and
+ * therefore isn't cluster aligned as well.
+ *
+ * Returns:
+ * 0: if no clusters could be allocated. *bytes is set to 0,
+ * *host_offset is left unchanged.
+ *
+ * 1: if new clusters were allocated. *bytes may be decreased if the
+ * new allocation doesn't cover all of the requested area.
+ * *host_offset is updated to contain the host offset of the first
+ * newly allocated cluster.
+ *
+ * -errno: in error cases
+ */
+static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
+ uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m)
+{
+ BDRVQcowState *s = bs->opaque;
+ int l2_index;
+ uint64_t *l2_table;
+ uint64_t entry;
+ unsigned int nb_clusters;
+ int ret;
+
+ uint64_t alloc_cluster_offset;
+
+ trace_qcow2_handle_alloc(qemu_coroutine_self(), guest_offset, *host_offset,
+ *bytes);
+ assert(*bytes > 0);
+
+ /*
+ * Calculate the number of clusters to look for. We stop at L2 table
+ * boundaries to keep things simple.
+ */
+ nb_clusters =
+ size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes);
+
+ l2_index = offset_to_l2_index(s, guest_offset);
+ nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
+
+ /* Find L2 entry for the first involved cluster */
+ ret = get_cluster_table(bs, guest_offset, &l2_table, &l2_index);
+ if (ret < 0) {
+ return ret;
+ }
+
+ entry = be64_to_cpu(l2_table[l2_index]);
+
+ /* For the moment, overwrite compressed clusters one by one */
+ if (entry & QCOW_OFLAG_COMPRESSED) {
+ nb_clusters = 1;
+ } else {
+ nb_clusters = count_cow_clusters(s, nb_clusters, l2_table, l2_index);
+ }
+
+ /* This function is only called when there were no non-COW clusters, so if
+ * we can't find any unallocated or COW clusters either, something is
+ * wrong with our code. */
+ assert(nb_clusters > 0);
+
+ qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
+
+ /* Allocate, if necessary at a given offset in the image file */
+ alloc_cluster_offset = start_of_cluster(s, *host_offset);
+ ret = do_alloc_cluster_offset(bs, guest_offset, &alloc_cluster_offset,
+ &nb_clusters);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ /* Can't extend contiguous allocation */
+ if (nb_clusters == 0) {
+ *bytes = 0;
+ return 0;
+ }
+
+ /* !*host_offset would overwrite the image header and is reserved for "no
+ * host offset preferred". If 0 was a valid host offset, it'd trigger the
+ * following overlap check; do that now to avoid having an invalid value in
+ * *host_offset. */
+ if (!alloc_cluster_offset) {
+ ret = qcow2_pre_write_overlap_check(bs, 0, alloc_cluster_offset,
+ nb_clusters * s->cluster_size);
+ assert(ret < 0);
+ goto fail;
+ }
+
+ /*
+ * Save info needed for meta data update.
+ *
+ * requested_sectors: Number of sectors from the start of the first
+ * newly allocated cluster to the end of the (possibly shortened
+ * before) write request.
+ *
+ * avail_sectors: Number of sectors from the start of the first
+ * newly allocated to the end of the last newly allocated cluster.
+ *
+ * nb_sectors: The number of sectors from the start of the first
+ * newly allocated cluster to the end of the area that the write
+ * request actually writes to (excluding COW at the end)
+ */
+ int requested_sectors =
+ (*bytes + offset_into_cluster(s, guest_offset))
+ >> BDRV_SECTOR_BITS;
+ int avail_sectors = nb_clusters
+ << (s->cluster_bits - BDRV_SECTOR_BITS);
+ int alloc_n_start = offset_into_cluster(s, guest_offset)
+ >> BDRV_SECTOR_BITS;
+ int nb_sectors = MIN(requested_sectors, avail_sectors);
+ QCowL2Meta *old_m = *m;
+
+ *m = g_malloc0(sizeof(**m));
+
+ **m = (QCowL2Meta) {
+ .next = old_m,
+
+ .alloc_offset = alloc_cluster_offset,
+ .offset = start_of_cluster(s, guest_offset),
+ .nb_clusters = nb_clusters,
+ .nb_available = nb_sectors,
+
+ .cow_start = {
+ .offset = 0,
+ .nb_sectors = alloc_n_start,
+ },
+ .cow_end = {
+ .offset = nb_sectors * BDRV_SECTOR_SIZE,
+ .nb_sectors = avail_sectors - nb_sectors,
+ },
+ };
+ qemu_co_queue_init(&(*m)->dependent_requests);
+ QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight);
+
+ *host_offset = alloc_cluster_offset + offset_into_cluster(s, guest_offset);
+ *bytes = MIN(*bytes, (nb_sectors * BDRV_SECTOR_SIZE)
+ - offset_into_cluster(s, guest_offset));
+ assert(*bytes != 0);
+
+ return 1;
+
+fail:
+ if (*m && (*m)->nb_clusters > 0) {
+ QLIST_REMOVE(*m, next_in_flight);
+ }
+ return ret;
+}
+
+/*
+ * alloc_cluster_offset
+ *
+ * For a given offset on the virtual disk, find the cluster offset in qcow2
+ * file. If the offset is not found, allocate a new cluster.
+ *
+ * If the cluster was already allocated, m->nb_clusters is set to 0 and
+ * other fields in m are meaningless.
+ *
+ * If the cluster is newly allocated, m->nb_clusters is set to the number of
+ * contiguous clusters that have been allocated. In this case, the other
+ * fields of m are valid and contain information about the first allocated
+ * cluster.
+ *
+ * If the request conflicts with another write request in flight, the coroutine
+ * is queued and will be reentered when the dependency has completed.
+ *
+ * Return 0 on success and -errno in error cases
+ */
+int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
+ int *num, uint64_t *host_offset, QCowL2Meta **m)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t start, remaining;
+ uint64_t cluster_offset;
+ uint64_t cur_bytes;
+ int ret;
+
+ trace_qcow2_alloc_clusters_offset(qemu_coroutine_self(), offset, *num);
+
+ assert((offset & ~BDRV_SECTOR_MASK) == 0);
+
+again:
+ start = offset;
+ remaining = (uint64_t)*num << BDRV_SECTOR_BITS;
+ cluster_offset = 0;
+ *host_offset = 0;
+ cur_bytes = 0;
+ *m = NULL;
+
+ while (true) {
+
+ if (!*host_offset) {
+ *host_offset = start_of_cluster(s, cluster_offset);
+ }
+
+ assert(remaining >= cur_bytes);
+
+ start += cur_bytes;
+ remaining -= cur_bytes;
+ cluster_offset += cur_bytes;
+
+ if (remaining == 0) {
+ break;
+ }
+
+ cur_bytes = remaining;
+
+ /*
+ * Now start gathering as many contiguous clusters as possible:
+ *
+ * 1. Check for overlaps with in-flight allocations
+ *
+ * a) Overlap not in the first cluster -> shorten this request and
+ * let the caller handle the rest in its next loop iteration.
+ *
+ * b) Real overlaps of two requests. Yield and restart the search
+ * for contiguous clusters (the situation could have changed
+ * while we were sleeping)
+ *
+ * c) TODO: Request starts in the same cluster as the in-flight
+ * allocation ends. Shorten the COW of the in-fight allocation,
+ * set cluster_offset to write to the same cluster and set up
+ * the right synchronisation between the in-flight request and
+ * the new one.
+ */
+ ret = handle_dependencies(bs, start, &cur_bytes, m);
+ if (ret == -EAGAIN) {
+ /* Currently handle_dependencies() doesn't yield if we already had
+ * an allocation. If it did, we would have to clean up the L2Meta
+ * structs before starting over. */
+ assert(*m == NULL);
+ goto again;
+ } else if (ret < 0) {
+ return ret;
+ } else if (cur_bytes == 0) {
+ break;
+ } else {
+ /* handle_dependencies() may have decreased cur_bytes (shortened
+ * the allocations below) so that the next dependency is processed
+ * correctly during the next loop iteration. */
+ }
+
+ /*
+ * 2. Count contiguous COPIED clusters.
+ */
+ ret = handle_copied(bs, start, &cluster_offset, &cur_bytes, m);
+ if (ret < 0) {
+ return ret;
+ } else if (ret) {
+ continue;
+ } else if (cur_bytes == 0) {
+ break;
+ }
+
+ /*
+ * 3. If the request still hasn't completed, allocate new clusters,
+ * considering any cluster_offset of steps 1c or 2.
+ */
+ ret = handle_alloc(bs, start, &cluster_offset, &cur_bytes, m);
+ if (ret < 0) {
+ return ret;
+ } else if (ret) {
+ continue;
+ } else {
+ assert(cur_bytes == 0);
+ break;
+ }
+ }
+
+ *num -= remaining >> BDRV_SECTOR_BITS;
+ assert(*num > 0);
+ assert(*host_offset != 0);
+
+ return 0;
+}
+
+static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
+ const uint8_t *buf, int buf_size)
+{
+ z_stream strm1, *strm = &strm1;
+ int ret, out_len;
+
+ memset(strm, 0, sizeof(*strm));
+
+ strm->next_in = (uint8_t *)buf;
+ strm->avail_in = buf_size;
+ strm->next_out = out_buf;
+ strm->avail_out = out_buf_size;
+
+ ret = inflateInit2(strm, -12);
+ if (ret != Z_OK)
+ return -1;
+ ret = inflate(strm, Z_FINISH);
+ out_len = strm->next_out - out_buf;
+ if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
+ out_len != out_buf_size) {
+ inflateEnd(strm);
+ return -1;
+ }
+ inflateEnd(strm);
+ return 0;
+}
+
+int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
+{
+ BDRVQcowState *s = bs->opaque;
+ int ret, csize, nb_csectors, sector_offset;
+ uint64_t coffset;
+
+ coffset = cluster_offset & s->cluster_offset_mask;
+ if (s->cluster_cache_offset != coffset) {
+ nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
+ sector_offset = coffset & 511;
+ csize = nb_csectors * 512 - sector_offset;
+ BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
+ ret = bdrv_read(bs->file, coffset >> 9, s->cluster_data, nb_csectors);
+ if (ret < 0) {
+ return ret;
+ }
+ if (decompress_buffer(s->cluster_cache, s->cluster_size,
+ s->cluster_data + sector_offset, csize) < 0) {
+ return -EIO;
+ }
+ s->cluster_cache_offset = coffset;
+ }
+ return 0;
+}
+
+/*
+ * This discards as many clusters of nb_clusters as possible at once (i.e.
+ * all clusters in the same L2 table) and returns the number of discarded
+ * clusters.
+ */
+static int discard_single_l2(BlockDriverState *bs, uint64_t offset,
+ unsigned int nb_clusters, enum qcow2_discard_type type, bool full_discard)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t *l2_table;
+ int l2_index;
+ int ret;
+ int i;
+
+ ret = get_cluster_table(bs, offset, &l2_table, &l2_index);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* Limit nb_clusters to one L2 table */
+ nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
+
+ for (i = 0; i < nb_clusters; i++) {
+ uint64_t old_l2_entry;
+
+ old_l2_entry = be64_to_cpu(l2_table[l2_index + i]);
+
+ /*
+ * If full_discard is false, make sure that a discarded area reads back
+ * as zeroes for v3 images (we cannot do it for v2 without actually
+ * writing a zero-filled buffer). We can skip the operation if the
+ * cluster is already marked as zero, or if it's unallocated and we
+ * don't have a backing file.
+ *
+ * TODO We might want to use bdrv_get_block_status(bs) here, but we're
+ * holding s->lock, so that doesn't work today.
+ *
+ * If full_discard is true, the sector should not read back as zeroes,
+ * but rather fall through to the backing file.
+ */
+ switch (qcow2_get_cluster_type(old_l2_entry)) {
+ case QCOW2_CLUSTER_UNALLOCATED:
+ if (full_discard || !bs->backing_hd) {
+ continue;
+ }
+ break;
+
+ case QCOW2_CLUSTER_ZERO:
+ if (!full_discard) {
+ continue;
+ }
+ break;
+
+ case QCOW2_CLUSTER_NORMAL:
+ case QCOW2_CLUSTER_COMPRESSED:
+ break;
+
+ default:
+ abort();
+ }
+
+ /* First remove L2 entries */
+ qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table);
+ if (!full_discard && s->qcow_version >= 3) {
+ l2_table[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO);
+ } else {
+ l2_table[l2_index + i] = cpu_to_be64(0);
+ }
+
+ /* Then decrease the refcount */
+ qcow2_free_any_clusters(bs, old_l2_entry, 1, type);
+ }
+
+ qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
+
+ return nb_clusters;
+}
+
+int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
+ int nb_sectors, enum qcow2_discard_type type, bool full_discard)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t end_offset;
+ unsigned int nb_clusters;
+ int ret;
+
+ end_offset = offset + (nb_sectors << BDRV_SECTOR_BITS);
+
+ /* Round start up and end down */
+ offset = align_offset(offset, s->cluster_size);
+ end_offset = start_of_cluster(s, end_offset);
+
+ if (offset > end_offset) {
+ return 0;
+ }
+
+ nb_clusters = size_to_clusters(s, end_offset - offset);
+
+ s->cache_discards = true;
+
+ /* Each L2 table is handled by its own loop iteration */
+ while (nb_clusters > 0) {
+ ret = discard_single_l2(bs, offset, nb_clusters, type, full_discard);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ nb_clusters -= ret;
+ offset += (ret * s->cluster_size);
+ }
+
+ ret = 0;
+fail:
+ s->cache_discards = false;
+ qcow2_process_discards(bs, ret);
+
+ return ret;
+}
+
+/*
+ * This zeroes as many clusters of nb_clusters as possible at once (i.e.
+ * all clusters in the same L2 table) and returns the number of zeroed
+ * clusters.
+ */
+static int zero_single_l2(BlockDriverState *bs, uint64_t offset,
+ unsigned int nb_clusters)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t *l2_table;
+ int l2_index;
+ int ret;
+ int i;
+
+ ret = get_cluster_table(bs, offset, &l2_table, &l2_index);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* Limit nb_clusters to one L2 table */
+ nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
+
+ for (i = 0; i < nb_clusters; i++) {
+ uint64_t old_offset;
+
+ old_offset = be64_to_cpu(l2_table[l2_index + i]);
+
+ /* Update L2 entries */
+ qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table);
+ if (old_offset & QCOW_OFLAG_COMPRESSED) {
+ l2_table[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO);
+ qcow2_free_any_clusters(bs, old_offset, 1, QCOW2_DISCARD_REQUEST);
+ } else {
+ l2_table[l2_index + i] |= cpu_to_be64(QCOW_OFLAG_ZERO);
+ }
+ }
+
+ qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
+
+ return nb_clusters;
+}
+
+int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors)
+{
+ BDRVQcowState *s = bs->opaque;
+ unsigned int nb_clusters;
+ int ret;
+
+ /* The zero flag is only supported by version 3 and newer */
+ if (s->qcow_version < 3) {
+ return -ENOTSUP;
+ }
+
+ /* Each L2 table is handled by its own loop iteration */
+ nb_clusters = size_to_clusters(s, nb_sectors << BDRV_SECTOR_BITS);
+
+ s->cache_discards = true;
+
+ while (nb_clusters > 0) {
+ ret = zero_single_l2(bs, offset, nb_clusters);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ nb_clusters -= ret;
+ offset += (ret * s->cluster_size);
+ }
+
+ ret = 0;
+fail:
+ s->cache_discards = false;
+ qcow2_process_discards(bs, ret);
+
+ return ret;
+}
+
+/*
+ * Expands all zero clusters in a specific L1 table (or deallocates them, for
+ * non-backed non-pre-allocated zero clusters).
+ *
+ * l1_entries and *visited_l1_entries are used to keep track of progress for
+ * status_cb(). l1_entries contains the total number of L1 entries and
+ * *visited_l1_entries counts all visited L1 entries.
+ */
+static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table,
+ int l1_size, int64_t *visited_l1_entries,
+ int64_t l1_entries,
+ BlockDriverAmendStatusCB *status_cb)
+{
+ BDRVQcowState *s = bs->opaque;
+ bool is_active_l1 = (l1_table == s->l1_table);
+ uint64_t *l2_table = NULL;
+ int ret;
+ int i, j;
+
+ if (!is_active_l1) {
+ /* inactive L2 tables require a buffer to be stored in when loading
+ * them from disk */
+ l2_table = qemu_try_blockalign(bs->file, s->cluster_size);
+ if (l2_table == NULL) {
+ return -ENOMEM;
+ }
+ }
+
+ for (i = 0; i < l1_size; i++) {
+ uint64_t l2_offset = l1_table[i] & L1E_OFFSET_MASK;
+ bool l2_dirty = false;
+ uint64_t l2_refcount;
+
+ if (!l2_offset) {
+ /* unallocated */
+ (*visited_l1_entries)++;
+ if (status_cb) {
+ status_cb(bs, *visited_l1_entries, l1_entries);
+ }
+ continue;
+ }
+
+ if (offset_into_cluster(s, l2_offset)) {
+ qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#"
+ PRIx64 " unaligned (L1 index: %#x)",
+ l2_offset, i);
+ ret = -EIO;
+ goto fail;
+ }
+
+ if (is_active_l1) {
+ /* get active L2 tables from cache */
+ ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset,
+ (void **)&l2_table);
+ } else {
+ /* load inactive L2 tables from disk */
+ ret = bdrv_read(bs->file, l2_offset / BDRV_SECTOR_SIZE,
+ (void *)l2_table, s->cluster_sectors);
+ }
+ if (ret < 0) {
+ goto fail;
+ }
+
+ ret = qcow2_get_refcount(bs, l2_offset >> s->cluster_bits,
+ &l2_refcount);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ for (j = 0; j < s->l2_size; j++) {
+ uint64_t l2_entry = be64_to_cpu(l2_table[j]);
+ int64_t offset = l2_entry & L2E_OFFSET_MASK;
+ int cluster_type = qcow2_get_cluster_type(l2_entry);
+ bool preallocated = offset != 0;
+
+ if (cluster_type != QCOW2_CLUSTER_ZERO) {
+ continue;
+ }
+
+ if (!preallocated) {
+ if (!bs->backing_hd) {
+ /* not backed; therefore we can simply deallocate the
+ * cluster */
+ l2_table[j] = 0;
+ l2_dirty = true;
+ continue;
+ }
+
+ offset = qcow2_alloc_clusters(bs, s->cluster_size);
+ if (offset < 0) {
+ ret = offset;
+ goto fail;
+ }
+
+ if (l2_refcount > 1) {
+ /* For shared L2 tables, set the refcount accordingly (it is
+ * already 1 and needs to be l2_refcount) */
+ ret = qcow2_update_cluster_refcount(bs,
+ offset >> s->cluster_bits,
+ refcount_diff(1, l2_refcount), false,
+ QCOW2_DISCARD_OTHER);
+ if (ret < 0) {
+ qcow2_free_clusters(bs, offset, s->cluster_size,
+ QCOW2_DISCARD_OTHER);
+ goto fail;
+ }
+ }
+ }
+
+ if (offset_into_cluster(s, offset)) {
+ qcow2_signal_corruption(bs, true, -1, -1, "Data cluster offset "
+ "%#" PRIx64 " unaligned (L2 offset: %#"
+ PRIx64 ", L2 index: %#x)", offset,
+ l2_offset, j);
+ if (!preallocated) {
+ qcow2_free_clusters(bs, offset, s->cluster_size,
+ QCOW2_DISCARD_ALWAYS);
+ }
+ ret = -EIO;
+ goto fail;
+ }
+
+ ret = qcow2_pre_write_overlap_check(bs, 0, offset, s->cluster_size);
+ if (ret < 0) {
+ if (!preallocated) {
+ qcow2_free_clusters(bs, offset, s->cluster_size,
+ QCOW2_DISCARD_ALWAYS);
+ }
+ goto fail;
+ }
+
+ ret = bdrv_write_zeroes(bs->file, offset / BDRV_SECTOR_SIZE,
+ s->cluster_sectors, 0);
+ if (ret < 0) {
+ if (!preallocated) {
+ qcow2_free_clusters(bs, offset, s->cluster_size,
+ QCOW2_DISCARD_ALWAYS);
+ }
+ goto fail;
+ }
+
+ if (l2_refcount == 1) {
+ l2_table[j] = cpu_to_be64(offset | QCOW_OFLAG_COPIED);
+ } else {
+ l2_table[j] = cpu_to_be64(offset);
+ }
+ l2_dirty = true;
+ }
+
+ if (is_active_l1) {
+ if (l2_dirty) {
+ qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table);
+ qcow2_cache_depends_on_flush(s->l2_table_cache);
+ }
+ qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
+ } else {
+ if (l2_dirty) {
+ ret = qcow2_pre_write_overlap_check(bs,
+ QCOW2_OL_INACTIVE_L2 | QCOW2_OL_ACTIVE_L2, l2_offset,
+ s->cluster_size);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ ret = bdrv_write(bs->file, l2_offset / BDRV_SECTOR_SIZE,
+ (void *)l2_table, s->cluster_sectors);
+ if (ret < 0) {
+ goto fail;
+ }
+ }
+ }
+
+ (*visited_l1_entries)++;
+ if (status_cb) {
+ status_cb(bs, *visited_l1_entries, l1_entries);
+ }
+ }
+
+ ret = 0;
+
+fail:
+ if (l2_table) {
+ if (!is_active_l1) {
+ qemu_vfree(l2_table);
+ } else {
+ qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
+ }
+ }
+ return ret;
+}
+
+/*
+ * For backed images, expands all zero clusters on the image. For non-backed
+ * images, deallocates all non-pre-allocated zero clusters (and claims the
+ * allocation for pre-allocated ones). This is important for downgrading to a
+ * qcow2 version which doesn't yet support metadata zero clusters.
+ */
+int qcow2_expand_zero_clusters(BlockDriverState *bs,
+ BlockDriverAmendStatusCB *status_cb)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t *l1_table = NULL;
+ int64_t l1_entries = 0, visited_l1_entries = 0;
+ int ret;
+ int i, j;
+
+ if (status_cb) {
+ l1_entries = s->l1_size;
+ for (i = 0; i < s->nb_snapshots; i++) {
+ l1_entries += s->snapshots[i].l1_size;
+ }
+ }
+
+ ret = expand_zero_clusters_in_l1(bs, s->l1_table, s->l1_size,
+ &visited_l1_entries, l1_entries,
+ status_cb);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ /* Inactive L1 tables may point to active L2 tables - therefore it is
+ * necessary to flush the L2 table cache before trying to access the L2
+ * tables pointed to by inactive L1 entries (else we might try to expand
+ * zero clusters that have already been expanded); furthermore, it is also
+ * necessary to empty the L2 table cache, since it may contain tables which
+ * are now going to be modified directly on disk, bypassing the cache.
+ * qcow2_cache_empty() does both for us. */
+ ret = qcow2_cache_empty(bs, s->l2_table_cache);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ for (i = 0; i < s->nb_snapshots; i++) {
+ int l1_sectors = (s->snapshots[i].l1_size * sizeof(uint64_t) +
+ BDRV_SECTOR_SIZE - 1) / BDRV_SECTOR_SIZE;
+
+ l1_table = g_realloc(l1_table, l1_sectors * BDRV_SECTOR_SIZE);
+
+ ret = bdrv_read(bs->file, s->snapshots[i].l1_table_offset /
+ BDRV_SECTOR_SIZE, (void *)l1_table, l1_sectors);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ for (j = 0; j < s->snapshots[i].l1_size; j++) {
+ be64_to_cpus(&l1_table[j]);
+ }
+
+ ret = expand_zero_clusters_in_l1(bs, l1_table, s->snapshots[i].l1_size,
+ &visited_l1_entries, l1_entries,
+ status_cb);
+ if (ret < 0) {
+ goto fail;
+ }
+ }
+
+ ret = 0;
+
+fail:
+ g_free(l1_table);
+ return ret;
+}
Code Review / kvmfornfv.git / blobdiff