--- /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 "vl.h"
+#include "block_int.h"
+#include <zlib.h>
+#include "aes.h"
+#include <assert.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.
+*/
+
+//#define DEBUG_ALLOC
+//#define DEBUG_ALLOC2
+
+#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
+#define QCOW_VERSION 2
+
+#define QCOW_CRYPT_NONE 0
+#define QCOW_CRYPT_AES 1
+
+/* indicate that the refcount of the referenced cluster is exactly one. */
+#define QCOW_OFLAG_COPIED (1LL << 63)
+/* indicate that the cluster is compressed (they never have the copied flag) */
+#define QCOW_OFLAG_COMPRESSED (1LL << 62)
+
+#define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
+
+#ifndef offsetof
+#define offsetof(type, field) ((size_t) &((type *)0)->field)
+#endif
+
+typedef struct QCowHeader {
+ uint32_t magic;
+ uint32_t version;
+ uint64_t backing_file_offset;
+ uint32_t backing_file_size;
+ uint32_t cluster_bits;
+ uint64_t size; /* in bytes */
+ uint32_t crypt_method;
+ uint32_t l1_size; /* XXX: save number of clusters instead ? */
+ uint64_t l1_table_offset;
+ uint64_t refcount_table_offset;
+ uint32_t refcount_table_clusters;
+ uint32_t nb_snapshots;
+ uint64_t snapshots_offset;
+} QCowHeader;
+
+typedef struct __attribute__((packed)) QCowSnapshotHeader {
+ /* header is 8 byte aligned */
+ uint64_t l1_table_offset;
+
+ uint32_t l1_size;
+ uint16_t id_str_size;
+ uint16_t name_size;
+
+ uint32_t date_sec;
+ uint32_t date_nsec;
+
+ uint64_t vm_clock_nsec;
+
+ uint32_t vm_state_size;
+ uint32_t extra_data_size; /* for extension */
+ /* extra data follows */
+ /* id_str follows */
+ /* name follows */
+} QCowSnapshotHeader;
+
+#define L2_CACHE_SIZE 16
+
+typedef struct QCowSnapshot {
+ uint64_t l1_table_offset;
+ uint32_t l1_size;
+ char *id_str;
+ char *name;
+ uint32_t vm_state_size;
+ uint32_t date_sec;
+ uint32_t date_nsec;
+ uint64_t vm_clock_nsec;
+} QCowSnapshot;
+
+typedef struct BDRVQcowState {
+ BlockDriverState *hd;
+ int cluster_bits;
+ int cluster_size;
+ int cluster_sectors;
+ int l2_bits;
+ int l2_size;
+ int l1_size;
+ int l1_vm_state_index;
+ int csize_shift;
+ int csize_mask;
+ uint64_t cluster_offset_mask;
+ uint64_t l1_table_offset;
+ uint64_t *l1_table;
+ uint64_t *l2_cache;
+ uint64_t l2_cache_offsets[L2_CACHE_SIZE];
+ uint32_t l2_cache_counts[L2_CACHE_SIZE];
+ uint8_t *cluster_cache;
+ uint8_t *cluster_data;
+ uint64_t cluster_cache_offset;
+
+ uint64_t *refcount_table;
+ uint64_t refcount_table_offset;
+ uint32_t refcount_table_size;
+ uint64_t refcount_block_cache_offset;
+ uint16_t *refcount_block_cache;
+ int64_t free_cluster_index;
+ int64_t free_byte_offset;
+
+ uint32_t crypt_method; /* current crypt method, 0 if no key yet */
+ uint32_t crypt_method_header;
+ AES_KEY aes_encrypt_key;
+ AES_KEY aes_decrypt_key;
+ uint64_t snapshots_offset;
+ int snapshots_size;
+ int nb_snapshots;
+ QCowSnapshot *snapshots;
+} BDRVQcowState;
+
+static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset);
+static int qcow_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors);
+static int qcow_read_snapshots(BlockDriverState *bs);
+static void qcow_free_snapshots(BlockDriverState *bs);
+static int refcount_init(BlockDriverState *bs);
+static void refcount_close(BlockDriverState *bs);
+static int get_refcount(BlockDriverState *bs, int64_t cluster_index);
+static int update_cluster_refcount(BlockDriverState *bs,
+ int64_t cluster_index,
+ int addend);
+static void update_refcount(BlockDriverState *bs,
+ int64_t offset, int64_t length,
+ int addend);
+static int64_t alloc_clusters(BlockDriverState *bs, int64_t size);
+static int64_t alloc_bytes(BlockDriverState *bs, int size);
+static void free_clusters(BlockDriverState *bs,
+ int64_t offset, int64_t size);
+#ifdef DEBUG_ALLOC
+static void check_refcounts(BlockDriverState *bs);
+#endif
+
+static int qcow_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) == QCOW_VERSION)
+ return 100;
+ else
+ return 0;
+}
+
+static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
+{
+ BDRVQcowState *s = bs->opaque;
+ int len, i, shift, ret;
+ QCowHeader header;
+
+ ret = bdrv_file_open(&s->hd, filename, flags);
+ if (ret < 0)
+ return ret;
+ if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(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 || header.version != QCOW_VERSION)
+ goto fail;
+ if (header.size <= 1 ||
+ header.cluster_bits < 9 ||
+ header.cluster_bits > 16)
+ goto fail;
+ if (header.crypt_method > QCOW_CRYPT_AES)
+ goto fail;
+ s->crypt_method_header = header.crypt_method;
+ if (s->crypt_method_header)
+ bs->encrypted = 1;
+ s->cluster_bits = header.cluster_bits;
+ s->cluster_size = 1 << s->cluster_bits;
+ s->cluster_sectors = 1 << (s->cluster_bits - 9);
+ s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
+ s->l2_size = 1 << s->l2_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);
+
+ s->snapshots_offset = header.snapshots_offset;
+ s->nb_snapshots = header.nb_snapshots;
+
+ /* read the level 1 table */
+ s->l1_size = header.l1_size;
+ shift = s->cluster_bits + s->l2_bits;
+ s->l1_vm_state_index = (header.size + (1LL << shift) - 1) >> shift;
+ /* the L1 table must contain at least enough entries to put
+ header.size bytes */
+ if (s->l1_size < s->l1_vm_state_index)
+ goto fail;
+ s->l1_table_offset = header.l1_table_offset;
+ s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
+ if (!s->l1_table)
+ goto fail;
+ if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
+ s->l1_size * sizeof(uint64_t))
+ goto fail;
+ for(i = 0;i < s->l1_size; i++) {
+ be64_to_cpus(&s->l1_table[i]);
+ }
+ /* alloc L2 cache */
+ s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
+ if (!s->l2_cache)
+ goto fail;
+ s->cluster_cache = qemu_malloc(s->cluster_size);
+ if (!s->cluster_cache)
+ goto fail;
+ /* one more sector for decompressed data alignment */
+ s->cluster_data = qemu_malloc(s->cluster_size + 512);
+ if (!s->cluster_data)
+ goto fail;
+ s->cluster_cache_offset = -1;
+
+ if (refcount_init(bs) < 0)
+ goto fail;
+
+ /* read the backing file name */
+ if (header.backing_file_offset != 0) {
+ len = header.backing_file_size;
+ if (len > 1023)
+ len = 1023;
+ if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
+ goto fail;
+ bs->backing_file[len] = '\0';
+ }
+ if (qcow_read_snapshots(bs) < 0)
+ goto fail;
+
+#ifdef DEBUG_ALLOC
+ check_refcounts(bs);
+#endif
+ return 0;
+
+ fail:
+ qcow_free_snapshots(bs);
+ refcount_close(bs);
+ qemu_free(s->l1_table);
+ qemu_free(s->l2_cache);
+ qemu_free(s->cluster_cache);
+ qemu_free(s->cluster_data);
+ bdrv_delete(s->hd);
+ return -1;
+}
+
+static int qcow_set_key(BlockDriverState *bs, const char *key)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint8_t keybuf[16];
+ int len, i;
+
+ 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];
+ }
+ s->crypt_method = s->crypt_method_header;
+
+ if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
+ return -1;
+ if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
+ return -1;
+#if 0
+ /* test */
+ {
+ uint8_t in[16];
+ uint8_t out[16];
+ uint8_t tmp[16];
+ for(i=0;i<16;i++)
+ in[i] = i;
+ AES_encrypt(in, tmp, &s->aes_encrypt_key);
+ AES_decrypt(tmp, out, &s->aes_decrypt_key);
+ for(i = 0; i < 16; i++)
+ printf(" %02x", tmp[i]);
+ printf("\n");
+ for(i = 0; i < 16; i++)
+ printf(" %02x", out[i]);
+ printf("\n");
+ }
+#endif
+ return 0;
+}
+
+/* The crypt function is compatible with the linux cryptoloop
+ algorithm for < 4 GB images. NOTE: out_buf == in_buf is
+ supported */
+static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
+ uint8_t *out_buf, const uint8_t *in_buf,
+ int nb_sectors, int enc,
+ const AES_KEY *key)
+{
+ union {
+ uint64_t ll[2];
+ uint8_t b[16];
+ } ivec;
+ int i;
+
+ for(i = 0; i < nb_sectors; i++) {
+ ivec.ll[0] = cpu_to_le64(sector_num);
+ ivec.ll[1] = 0;
+ AES_cbc_encrypt(in_buf, out_buf, 512, key,
+ ivec.b, enc);
+ sector_num++;
+ in_buf += 512;
+ out_buf += 512;
+ }
+}
+
+static int copy_sectors(BlockDriverState *bs, uint64_t start_sect,
+ uint64_t cluster_offset, int n_start, int n_end)
+{
+ BDRVQcowState *s = bs->opaque;
+ int n, ret;
+
+ n = n_end - n_start;
+ if (n <= 0)
+ return 0;
+ ret = qcow_read(bs, start_sect + n_start, s->cluster_data, n);
+ if (ret < 0)
+ return ret;
+ if (s->crypt_method) {
+ encrypt_sectors(s, start_sect + n_start,
+ s->cluster_data,
+ s->cluster_data, n, 1,
+ &s->aes_encrypt_key);
+ }
+ ret = bdrv_write(s->hd, (cluster_offset >> 9) + n_start,
+ s->cluster_data, n);
+ if (ret < 0)
+ return ret;
+ return 0;
+}
+
+static void l2_cache_reset(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+
+ memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
+ memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
+ memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
+}
+
+static inline int l2_cache_new_entry(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint32_t min_count;
+ int min_index, i;
+
+ /* find a new entry in the least used one */
+ min_index = 0;
+ min_count = 0xffffffff;
+ for(i = 0; i < L2_CACHE_SIZE; i++) {
+ if (s->l2_cache_counts[i] < min_count) {
+ min_count = s->l2_cache_counts[i];
+ min_index = i;
+ }
+ }
+ return min_index;
+}
+
+static int64_t align_offset(int64_t offset, int n)
+{
+ offset = (offset + n - 1) & ~(n - 1);
+ return offset;
+}
+
+static int grow_l1_table(BlockDriverState *bs, int min_size)
+{
+ BDRVQcowState *s = bs->opaque;
+ int new_l1_size, new_l1_size2, ret, i;
+ uint64_t *new_l1_table;
+ uint64_t new_l1_table_offset;
+ uint64_t data64;
+ uint32_t data32;
+
+ new_l1_size = s->l1_size;
+ if (min_size <= new_l1_size)
+ return 0;
+ while (min_size > new_l1_size) {
+ new_l1_size = (new_l1_size * 3 + 1) / 2;
+ }
+#ifdef DEBUG_ALLOC2
+ printf("grow l1_table from %d to %d\n", s->l1_size, new_l1_size);
+#endif
+
+ new_l1_size2 = sizeof(uint64_t) * new_l1_size;
+ new_l1_table = qemu_mallocz(new_l1_size2);
+ if (!new_l1_table)
+ return -ENOMEM;
+ memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
+
+ /* write new table (align to cluster) */
+ new_l1_table_offset = alloc_clusters(bs, new_l1_size2);
+
+ for(i = 0; i < s->l1_size; i++)
+ new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
+ ret = bdrv_pwrite(s->hd, new_l1_table_offset, new_l1_table, new_l1_size2);
+ if (ret != new_l1_size2)
+ goto fail;
+ for(i = 0; i < s->l1_size; i++)
+ new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
+
+ /* set new table */
+ data64 = cpu_to_be64(new_l1_table_offset);
+ if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_table_offset),
+ &data64, sizeof(data64)) != sizeof(data64))
+ goto fail;
+ data32 = cpu_to_be32(new_l1_size);
+ if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_size),
+ &data32, sizeof(data32)) != sizeof(data32))
+ goto fail;
+ qemu_free(s->l1_table);
+ free_clusters(bs, s->l1_table_offset, s->l1_size * sizeof(uint64_t));
+ s->l1_table_offset = new_l1_table_offset;
+ s->l1_table = new_l1_table;
+ s->l1_size = new_l1_size;
+ return 0;
+ fail:
+ qemu_free(s->l1_table);
+ return -EIO;
+}
+
+/* 'allocate' is:
+ *
+ * 0 not to allocate.
+ *
+ * 1 to allocate a normal cluster (for sector indexes 'n_start' to
+ * 'n_end')
+ *
+ * 2 to allocate a compressed cluster of size
+ * 'compressed_size'. 'compressed_size' must be > 0 and <
+ * cluster_size
+ *
+ * return 0 if not allocated.
+ */
+static uint64_t get_cluster_offset(BlockDriverState *bs,
+ uint64_t offset, int allocate,
+ int compressed_size,
+ int n_start, int n_end)
+{
+ BDRVQcowState *s = bs->opaque;
+ int min_index, i, j, l1_index, l2_index, ret;
+ uint64_t l2_offset, *l2_table, cluster_offset, tmp, old_l2_offset;
+
+ l1_index = offset >> (s->l2_bits + s->cluster_bits);
+ if (l1_index >= s->l1_size) {
+ /* outside l1 table is allowed: we grow the table if needed */
+ if (!allocate)
+ return 0;
+ if (grow_l1_table(bs, l1_index + 1) < 0)
+ return 0;
+ }
+ l2_offset = s->l1_table[l1_index];
+ if (!l2_offset) {
+ if (!allocate)
+ return 0;
+ l2_allocate:
+ old_l2_offset = l2_offset;
+ /* allocate a new l2 entry */
+ l2_offset = alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
+ /* update the L1 entry */
+ s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
+ tmp = cpu_to_be64(l2_offset | QCOW_OFLAG_COPIED);
+ if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),
+ &tmp, sizeof(tmp)) != sizeof(tmp))
+ return 0;
+ min_index = l2_cache_new_entry(bs);
+ l2_table = s->l2_cache + (min_index << s->l2_bits);
+
+ if (old_l2_offset == 0) {
+ memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
+ } else {
+ if (bdrv_pread(s->hd, old_l2_offset,
+ l2_table, s->l2_size * sizeof(uint64_t)) !=
+ s->l2_size * sizeof(uint64_t))
+ return 0;
+ }
+ if (bdrv_pwrite(s->hd, l2_offset,
+ l2_table, s->l2_size * sizeof(uint64_t)) !=
+ s->l2_size * sizeof(uint64_t))
+ return 0;
+ } else {
+ if (!(l2_offset & QCOW_OFLAG_COPIED)) {
+ if (allocate) {
+ free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
+ goto l2_allocate;
+ }
+ } else {
+ l2_offset &= ~QCOW_OFLAG_COPIED;
+ }
+ for(i = 0; i < L2_CACHE_SIZE; i++) {
+ if (l2_offset == s->l2_cache_offsets[i]) {
+ /* increment the hit count */
+ if (++s->l2_cache_counts[i] == 0xffffffff) {
+ for(j = 0; j < L2_CACHE_SIZE; j++) {
+ s->l2_cache_counts[j] >>= 1;
+ }
+ }
+ l2_table = s->l2_cache + (i << s->l2_bits);
+ goto found;
+ }
+ }
+ /* not found: load a new entry in the least used one */
+ min_index = l2_cache_new_entry(bs);
+ l2_table = s->l2_cache + (min_index << s->l2_bits);
+ if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
+ s->l2_size * sizeof(uint64_t))
+ return 0;
+ }
+ s->l2_cache_offsets[min_index] = l2_offset;
+ s->l2_cache_counts[min_index] = 1;
+ found:
+ l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
+ cluster_offset = be64_to_cpu(l2_table[l2_index]);
+ if (!cluster_offset) {
+ if (!allocate)
+ return cluster_offset;
+ } else if (!(cluster_offset & QCOW_OFLAG_COPIED)) {
+ if (!allocate)
+ return cluster_offset;
+ /* free the cluster */
+ if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
+ int nb_csectors;
+ nb_csectors = ((cluster_offset >> s->csize_shift) &
+ s->csize_mask) + 1;
+ free_clusters(bs, (cluster_offset & s->cluster_offset_mask) & ~511,
+ nb_csectors * 512);
+ } else {
+ free_clusters(bs, cluster_offset, s->cluster_size);
+ }
+ } else {
+ cluster_offset &= ~QCOW_OFLAG_COPIED;
+ return cluster_offset;
+ }
+ if (allocate == 1) {
+ /* allocate a new cluster */
+ cluster_offset = alloc_clusters(bs, s->cluster_size);
+
+ /* we must initialize the cluster content which won't be
+ written */
+ if ((n_end - n_start) < s->cluster_sectors) {
+ uint64_t start_sect;
+
+ start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
+ ret = copy_sectors(bs, start_sect,
+ cluster_offset, 0, n_start);
+ if (ret < 0)
+ return 0;
+ ret = copy_sectors(bs, start_sect,
+ cluster_offset, n_end, s->cluster_sectors);
+ if (ret < 0)
+ return 0;
+ }
+ tmp = cpu_to_be64(cluster_offset | QCOW_OFLAG_COPIED);
+ } else {
+ int nb_csectors;
+ cluster_offset = alloc_bytes(bs, compressed_size);
+ nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
+ (cluster_offset >> 9);
+ cluster_offset |= QCOW_OFLAG_COMPRESSED |
+ ((uint64_t)nb_csectors << s->csize_shift);
+ /* compressed clusters never have the copied flag */
+ tmp = cpu_to_be64(cluster_offset);
+ }
+ /* update L2 table */
+ l2_table[l2_index] = tmp;
+ if (bdrv_pwrite(s->hd,
+ l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp))
+ return 0;
+ return cluster_offset;
+}
+
+static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, int *pnum)
+{
+ BDRVQcowState *s = bs->opaque;
+ int index_in_cluster, n;
+ uint64_t cluster_offset;
+
+ cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
+ index_in_cluster = sector_num & (s->cluster_sectors - 1);
+ n = s->cluster_sectors - index_in_cluster;
+ if (n > nb_sectors)
+ n = nb_sectors;
+ *pnum = n;
+ return (cluster_offset != 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;
+}
+
+static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
+{
+ 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;
+ ret = bdrv_read(s->hd, coffset >> 9, s->cluster_data, nb_csectors);
+ if (ret < 0) {
+ return -1;
+ }
+ if (decompress_buffer(s->cluster_cache, s->cluster_size,
+ s->cluster_data + sector_offset, csize) < 0) {
+ return -1;
+ }
+ s->cluster_cache_offset = coffset;
+ }
+ return 0;
+}
+
+static int qcow_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ BDRVQcowState *s = bs->opaque;
+ int ret, index_in_cluster, n;
+ uint64_t cluster_offset;
+
+ while (nb_sectors > 0) {
+ cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
+ index_in_cluster = sector_num & (s->cluster_sectors - 1);
+ n = s->cluster_sectors - index_in_cluster;
+ if (n > nb_sectors)
+ n = nb_sectors;
+ if (!cluster_offset) {
+ if (bs->backing_hd) {
+ /* read from the base image */
+ ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
+ if (ret < 0)
+ return -1;
+ } else {
+ memset(buf, 0, 512 * n);
+ }
+ } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
+ if (decompress_cluster(s, cluster_offset) < 0)
+ return -1;
+ memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
+ } else {
+ ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
+ if (ret != n * 512)
+ return -1;
+ if (s->crypt_method) {
+ encrypt_sectors(s, sector_num, buf, buf, n, 0,
+ &s->aes_decrypt_key);
+ }
+ }
+ nb_sectors -= n;
+ sector_num += n;
+ buf += n * 512;
+ }
+ return 0;
+}
+
+static int qcow_write(BlockDriverState *bs, int64_t sector_num,
+ const uint8_t *buf, int nb_sectors)
+{
+ BDRVQcowState *s = bs->opaque;
+ int ret, index_in_cluster, n;
+ uint64_t cluster_offset;
+
+ while (nb_sectors > 0) {
+ index_in_cluster = sector_num & (s->cluster_sectors - 1);
+ n = s->cluster_sectors - index_in_cluster;
+ if (n > nb_sectors)
+ n = nb_sectors;
+ cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0,
+ index_in_cluster,
+ index_in_cluster + n);
+ if (!cluster_offset)
+ return -1;
+ if (s->crypt_method) {
+ encrypt_sectors(s, sector_num, s->cluster_data, buf, n, 1,
+ &s->aes_encrypt_key);
+ ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512,
+ s->cluster_data, n * 512);
+ } else {
+ ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
+ }
+ if (ret != n * 512)
+ return -1;
+ nb_sectors -= n;
+ sector_num += n;
+ buf += n * 512;
+ }
+ s->cluster_cache_offset = -1; /* disable compressed cache */
+ return 0;
+}
+
+typedef struct {
+ int64_t sector_num;
+ uint8_t *buf;
+ int nb_sectors;
+ int n;
+ uint64_t cluster_offset;
+ uint8_t *cluster_data;
+ BlockDriverAIOCB *hd_aiocb;
+ BlockDriverAIOCB *backing_hd_aiocb;
+} QCowAIOCB;
+
+static void qcow_aio_delete(BlockDriverAIOCB *acb);
+
+static int qcow_aio_new(BlockDriverAIOCB *acb)
+{
+ BlockDriverState *bs = acb->bs;
+ BDRVQcowState *s = bs->opaque;
+ QCowAIOCB *acb1;
+ acb1 = qemu_mallocz(sizeof(QCowAIOCB));
+ if (!acb1)
+ return -1;
+ acb->opaque = acb1;
+ acb1->hd_aiocb = bdrv_aio_new(s->hd);
+ if (!acb1->hd_aiocb)
+ goto fail;
+ if (bs->backing_hd) {
+ acb1->backing_hd_aiocb = bdrv_aio_new(bs->backing_hd);
+ if (!acb1->backing_hd_aiocb)
+ goto fail;
+ }
+ return 0;
+ fail:
+ qcow_aio_delete(acb);
+ return -1;
+}
+
+static void qcow_aio_read_cb(void *opaque, int ret)
+{
+ BlockDriverAIOCB *acb = opaque;
+ BlockDriverState *bs = acb->bs;
+ BDRVQcowState *s = bs->opaque;
+ QCowAIOCB *acb1 = acb->opaque;
+ int index_in_cluster;
+
+ if (ret < 0) {
+ fail:
+ acb->cb(acb->cb_opaque, ret);
+ return;
+ }
+
+ redo:
+ /* post process the read buffer */
+ if (!acb1->cluster_offset) {
+ /* nothing to do */
+ } else if (acb1->cluster_offset & QCOW_OFLAG_COMPRESSED) {
+ /* nothing to do */
+ } else {
+ if (s->crypt_method) {
+ encrypt_sectors(s, acb1->sector_num, acb1->buf, acb1->buf,
+ acb1->n, 0,
+ &s->aes_decrypt_key);
+ }
+ }
+
+ acb1->nb_sectors -= acb1->n;
+ acb1->sector_num += acb1->n;
+ acb1->buf += acb1->n * 512;
+
+ if (acb1->nb_sectors == 0) {
+ /* request completed */
+ acb->cb(acb->cb_opaque, 0);
+ return;
+ }
+
+ /* prepare next AIO request */
+ acb1->cluster_offset = get_cluster_offset(bs,
+ acb1->sector_num << 9,
+ 0, 0, 0, 0);
+ index_in_cluster = acb1->sector_num & (s->cluster_sectors - 1);
+ acb1->n = s->cluster_sectors - index_in_cluster;
+ if (acb1->n > acb1->nb_sectors)
+ acb1->n = acb1->nb_sectors;
+
+ if (!acb1->cluster_offset) {
+ if (bs->backing_hd) {
+ /* read from the base image */
+ ret = bdrv_aio_read(acb1->backing_hd_aiocb, acb1->sector_num,
+ acb1->buf, acb1->n, qcow_aio_read_cb, acb);
+ if (ret < 0)
+ goto fail;
+ } else {
+ /* Note: in this case, no need to wait */
+ memset(acb1->buf, 0, 512 * acb1->n);
+ goto redo;
+ }
+ } else if (acb1->cluster_offset & QCOW_OFLAG_COMPRESSED) {
+ /* add AIO support for compressed blocks ? */
+ if (decompress_cluster(s, acb1->cluster_offset) < 0)
+ goto fail;
+ memcpy(acb1->buf,
+ s->cluster_cache + index_in_cluster * 512, 512 * acb1->n);
+ goto redo;
+ } else {
+ if ((acb1->cluster_offset & 511) != 0) {
+ ret = -EIO;
+ goto fail;
+ }
+ ret = bdrv_aio_read(acb1->hd_aiocb,
+ (acb1->cluster_offset >> 9) + index_in_cluster,
+ acb1->buf, acb1->n, qcow_aio_read_cb, acb);
+ if (ret < 0)
+ goto fail;
+ }
+}
+
+static int qcow_aio_read(BlockDriverAIOCB *acb, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ QCowAIOCB *acb1 = acb->opaque;
+
+ acb1->sector_num = sector_num;
+ acb1->buf = buf;
+ acb1->nb_sectors = nb_sectors;
+ acb1->n = 0;
+ acb1->cluster_offset = 0;
+
+ qcow_aio_read_cb(acb, 0);
+ return 0;
+}
+
+static void qcow_aio_write_cb(void *opaque, int ret)
+{
+ BlockDriverAIOCB *acb = opaque;
+ BlockDriverState *bs = acb->bs;
+ BDRVQcowState *s = bs->opaque;
+ QCowAIOCB *acb1 = acb->opaque;
+ int index_in_cluster;
+ uint64_t cluster_offset;
+ const uint8_t *src_buf;
+
+ if (ret < 0) {
+ fail:
+ acb->cb(acb->cb_opaque, ret);
+ return;
+ }
+
+ acb1->nb_sectors -= acb1->n;
+ acb1->sector_num += acb1->n;
+ acb1->buf += acb1->n * 512;
+
+ if (acb1->nb_sectors == 0) {
+ /* request completed */
+ acb->cb(acb->cb_opaque, 0);
+ return;
+ }
+
+ index_in_cluster = acb1->sector_num & (s->cluster_sectors - 1);
+ acb1->n = s->cluster_sectors - index_in_cluster;
+ if (acb1->n > acb1->nb_sectors)
+ acb1->n = acb1->nb_sectors;
+ cluster_offset = get_cluster_offset(bs, acb1->sector_num << 9, 1, 0,
+ index_in_cluster,
+ index_in_cluster + acb1->n);
+ if (!cluster_offset || (cluster_offset & 511) != 0) {
+ ret = -EIO;
+ goto fail;
+ }
+ if (s->crypt_method) {
+ if (!acb1->cluster_data) {
+ acb1->cluster_data = qemu_mallocz(s->cluster_size);
+ if (!acb1->cluster_data) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+ }
+ encrypt_sectors(s, acb1->sector_num, acb1->cluster_data, acb1->buf,
+ acb1->n, 1, &s->aes_encrypt_key);
+ src_buf = acb1->cluster_data;
+ } else {
+ src_buf = acb1->buf;
+ }
+ ret = bdrv_aio_write(acb1->hd_aiocb,
+ (cluster_offset >> 9) + index_in_cluster,
+ src_buf, acb1->n,
+ qcow_aio_write_cb, acb);
+ if (ret < 0)
+ goto fail;
+}
+
+static int qcow_aio_write(BlockDriverAIOCB *acb, int64_t sector_num,
+ const uint8_t *buf, int nb_sectors)
+{
+ QCowAIOCB *acb1 = acb->opaque;
+ BlockDriverState *bs = acb->bs;
+ BDRVQcowState *s = bs->opaque;
+
+ s->cluster_cache_offset = -1; /* disable compressed cache */
+
+ acb1->sector_num = sector_num;
+ acb1->buf = (uint8_t *)buf;
+ acb1->nb_sectors = nb_sectors;
+ acb1->n = 0;
+
+ qcow_aio_write_cb(acb, 0);
+ return 0;
+}
+
+static void qcow_aio_cancel(BlockDriverAIOCB *acb)
+{
+ QCowAIOCB *acb1 = acb->opaque;
+ if (acb1->hd_aiocb)
+ bdrv_aio_cancel(acb1->hd_aiocb);
+ if (acb1->backing_hd_aiocb)
+ bdrv_aio_cancel(acb1->backing_hd_aiocb);
+}
+
+static void qcow_aio_delete(BlockDriverAIOCB *acb)
+{
+ QCowAIOCB *acb1 = acb->opaque;
+ if (acb1->hd_aiocb)
+ bdrv_aio_delete(acb1->hd_aiocb);
+ if (acb1->backing_hd_aiocb)
+ bdrv_aio_delete(acb1->backing_hd_aiocb);
+ qemu_free(acb1->cluster_data);
+ qemu_free(acb1);
+}
+
+static void qcow_close(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ qemu_free(s->l1_table);
+ qemu_free(s->l2_cache);
+ qemu_free(s->cluster_cache);
+ qemu_free(s->cluster_data);
+ refcount_close(bs);
+ bdrv_delete(s->hd);
+}
+
+/* XXX: use std qcow open function ? */
+typedef struct QCowCreateState {
+ int cluster_size;
+ int cluster_bits;
+ uint16_t *refcount_block;
+ uint64_t *refcount_table;
+ int64_t l1_table_offset;
+ int64_t refcount_table_offset;
+ int64_t refcount_block_offset;
+} QCowCreateState;
+
+static void create_refcount_update(QCowCreateState *s,
+ int64_t offset, int64_t size)
+{
+ int refcount;
+ int64_t start, last, cluster_offset;
+ uint16_t *p;
+
+ start = offset & ~(s->cluster_size - 1);
+ last = (offset + size - 1) & ~(s->cluster_size - 1);
+ for(cluster_offset = start; cluster_offset <= last;
+ cluster_offset += s->cluster_size) {
+ p = &s->refcount_block[cluster_offset >> s->cluster_bits];
+ refcount = be16_to_cpu(*p);
+ refcount++;
+ *p = cpu_to_be16(refcount);
+ }
+}
+
+static int qcow_create(const char *filename, int64_t total_size,
+ const char *backing_file, int flags)
+{
+ int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
+ QCowHeader header;
+ uint64_t tmp, offset;
+ QCowCreateState s1, *s = &s1;
+
+ memset(s, 0, sizeof(*s));
+
+ fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
+ if (fd < 0)
+ return -1;
+ memset(&header, 0, sizeof(header));
+ header.magic = cpu_to_be32(QCOW_MAGIC);
+ header.version = cpu_to_be32(QCOW_VERSION);
+ header.size = cpu_to_be64(total_size * 512);
+ header_size = sizeof(header);
+ backing_filename_len = 0;
+ if (backing_file) {
+ header.backing_file_offset = cpu_to_be64(header_size);
+ backing_filename_len = strlen(backing_file);
+ header.backing_file_size = cpu_to_be32(backing_filename_len);
+ header_size += backing_filename_len;
+ }
+ s->cluster_bits = 12; /* 4 KB clusters */
+ s->cluster_size = 1 << s->cluster_bits;
+ header.cluster_bits = cpu_to_be32(s->cluster_bits);
+ header_size = (header_size + 7) & ~7;
+ if (flags) {
+ header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
+ } else {
+ header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
+ }
+ l2_bits = s->cluster_bits - 3;
+ shift = s->cluster_bits + l2_bits;
+ l1_size = (((total_size * 512) + (1LL << shift) - 1) >> shift);
+ offset = align_offset(header_size, s->cluster_size);
+ s->l1_table_offset = offset;
+ header.l1_table_offset = cpu_to_be64(s->l1_table_offset);
+ header.l1_size = cpu_to_be32(l1_size);
+ offset += align_offset(l1_size, s->cluster_size);
+
+ s->refcount_table = qemu_mallocz(s->cluster_size);
+ if (!s->refcount_table)
+ goto fail;
+ s->refcount_block = qemu_mallocz(s->cluster_size);
+ if (!s->refcount_block)
+ goto fail;
+
+ s->refcount_table_offset = offset;
+ header.refcount_table_offset = cpu_to_be64(offset);
+ header.refcount_table_clusters = cpu_to_be32(1);
+ offset += s->cluster_size;
+
+ s->refcount_table[0] = cpu_to_be64(offset);
+ s->refcount_block_offset = offset;
+ offset += s->cluster_size;
+
+ /* update refcounts */
+ create_refcount_update(s, 0, header_size);
+ create_refcount_update(s, s->l1_table_offset, l1_size);
+ create_refcount_update(s, s->refcount_table_offset, s->cluster_size);
+ create_refcount_update(s, s->refcount_block_offset, s->cluster_size);
+
+ /* write all the data */
+ write(fd, &header, sizeof(header));
+ if (backing_file) {
+ write(fd, backing_file, backing_filename_len);
+ }
+ lseek(fd, s->l1_table_offset, SEEK_SET);
+ tmp = 0;
+ for(i = 0;i < l1_size; i++) {
+ write(fd, &tmp, sizeof(tmp));
+ }
+ lseek(fd, s->refcount_table_offset, SEEK_SET);
+ write(fd, s->refcount_table, s->cluster_size);
+
+ lseek(fd, s->refcount_block_offset, SEEK_SET);
+ write(fd, s->refcount_block, s->cluster_size);
+
+ qemu_free(s->refcount_table);
+ qemu_free(s->refcount_block);
+ close(fd);
+ return 0;
+ fail:
+ qemu_free(s->refcount_table);
+ qemu_free(s->refcount_block);
+ close(fd);
+ return -ENOMEM;
+}
+
+static int qcow_make_empty(BlockDriverState *bs)
+{
+#if 0
+ /* XXX: not correct */
+ BDRVQcowState *s = bs->opaque;
+ uint32_t l1_length = s->l1_size * sizeof(uint64_t);
+ int ret;
+
+ memset(s->l1_table, 0, l1_length);
+ if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
+ return -1;
+ ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
+ if (ret < 0)
+ return ret;
+
+ l2_cache_reset(bs);
+#endif
+ return 0;
+}
+
+/* XXX: put compressed sectors first, then all the cluster aligned
+ tables to avoid losing bytes in alignment */
+static int qcow_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(s->hd);
+ cluster_offset = (cluster_offset + 511) & ~511;
+ bdrv_truncate(s->hd, cluster_offset);
+ return 0;
+ }
+
+ if (nb_sectors != s->cluster_sectors)
+ return -EINVAL;
+
+ out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
+ if (!out_buf)
+ return -ENOMEM;
+
+ /* 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) {
+ qemu_free(out_buf);
+ return -1;
+ }
+
+ 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) {
+ qemu_free(out_buf);
+ deflateEnd(&strm);
+ return -1;
+ }
+ 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 */
+ qcow_write(bs, sector_num, buf, s->cluster_sectors);
+ } else {
+ cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
+ out_len, 0, 0);
+ cluster_offset &= s->cluster_offset_mask;
+ if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
+ qemu_free(out_buf);
+ return -1;
+ }
+ }
+
+ qemu_free(out_buf);
+ return 0;
+}
+
+static void qcow_flush(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ bdrv_flush(s->hd);
+}
+
+static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
+{
+ BDRVQcowState *s = bs->opaque;
+ bdi->cluster_size = s->cluster_size;
+ bdi->vm_state_offset = (int64_t)s->l1_vm_state_index <<
+ (s->cluster_bits + s->l2_bits);
+ return 0;
+}
+
+/*********************************************************/
+/* snapshot support */
+
+/* update the refcounts of snapshots and the copied flag */
+static int update_snapshot_refcount(BlockDriverState *bs,
+ int64_t l1_table_offset,
+ int l1_size,
+ int addend)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated;
+ int64_t old_offset, old_l2_offset;
+ int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount;
+
+ l2_cache_reset(bs);
+
+ l2_table = NULL;
+ l1_table = NULL;
+ l1_size2 = l1_size * sizeof(uint64_t);
+ l1_allocated = 0;
+ if (l1_table_offset != s->l1_table_offset) {
+ l1_table = qemu_malloc(l1_size2);
+ if (!l1_table)
+ goto fail;
+ l1_allocated = 1;
+ if (bdrv_pread(s->hd, l1_table_offset,
+ l1_table, l1_size2) != l1_size2)
+ goto fail;
+ for(i = 0;i < l1_size; i++)
+ be64_to_cpus(&l1_table[i]);
+ } else {
+ assert(l1_size == s->l1_size);
+ l1_table = s->l1_table;
+ l1_allocated = 0;
+ }
+
+ l2_size = s->l2_size * sizeof(uint64_t);
+ l2_table = qemu_malloc(l2_size);
+ if (!l2_table)
+ goto fail;
+ l1_modified = 0;
+ for(i = 0; i < l1_size; i++) {
+ l2_offset = l1_table[i];
+ if (l2_offset) {
+ old_l2_offset = l2_offset;
+ l2_offset &= ~QCOW_OFLAG_COPIED;
+ l2_modified = 0;
+ if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
+ goto fail;
+ for(j = 0; j < s->l2_size; j++) {
+ offset = be64_to_cpu(l2_table[j]);
+ if (offset != 0) {
+ old_offset = offset;
+ offset &= ~QCOW_OFLAG_COPIED;
+ if (offset & QCOW_OFLAG_COMPRESSED) {
+ nb_csectors = ((offset >> s->csize_shift) &
+ s->csize_mask) + 1;
+ if (addend != 0)
+ update_refcount(bs, (offset & s->cluster_offset_mask) & ~511,
+ nb_csectors * 512, addend);
+ /* compressed clusters are never modified */
+ refcount = 2;
+ } else {
+ if (addend != 0) {
+ refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend);
+ } else {
+ refcount = get_refcount(bs, offset >> s->cluster_bits);
+ }
+ }
+
+ if (refcount == 1) {
+ offset |= QCOW_OFLAG_COPIED;
+ }
+ if (offset != old_offset) {
+ l2_table[j] = cpu_to_be64(offset);
+ l2_modified = 1;
+ }
+ }
+ }
+ if (l2_modified) {
+ if (bdrv_pwrite(s->hd,
+ l2_offset, l2_table, l2_size) != l2_size)
+ goto fail;
+ }
+
+ if (addend != 0) {
+ refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend);
+ } else {
+ refcount = get_refcount(bs, l2_offset >> s->cluster_bits);
+ }
+ if (refcount == 1) {
+ l2_offset |= QCOW_OFLAG_COPIED;
+ }
+ if (l2_offset != old_l2_offset) {
+ l1_table[i] = l2_offset;
+ l1_modified = 1;
+ }
+ }
+ }
+ if (l1_modified) {
+ for(i = 0; i < l1_size; i++)
+ cpu_to_be64s(&l1_table[i]);
+ if (bdrv_pwrite(s->hd, l1_table_offset, l1_table,
+ l1_size2) != l1_size2)
+ goto fail;
+ for(i = 0; i < l1_size; i++)
+ be64_to_cpus(&l1_table[i]);
+ }
+ if (l1_allocated)
+ qemu_free(l1_table);
+ qemu_free(l2_table);
+ return 0;
+ fail:
+ if (l1_allocated)
+ qemu_free(l1_table);
+ qemu_free(l2_table);
+ return -EIO;
+}
+
+static void qcow_free_snapshots(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ int i;
+
+ for(i = 0; i < s->nb_snapshots; i++) {
+ qemu_free(s->snapshots[i].name);
+ qemu_free(s->snapshots[i].id_str);
+ }
+ qemu_free(s->snapshots);
+ s->snapshots = NULL;
+ s->nb_snapshots = 0;
+}
+
+static int qcow_read_snapshots(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ QCowSnapshotHeader h;
+ QCowSnapshot *sn;
+ int i, id_str_size, name_size;
+ int64_t offset;
+ uint32_t extra_data_size;
+
+ offset = s->snapshots_offset;
+ s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot));
+ if (!s->snapshots)
+ goto fail;
+ for(i = 0; i < s->nb_snapshots; i++) {
+ offset = align_offset(offset, 8);
+ if (bdrv_pread(s->hd, offset, &h, sizeof(h)) != sizeof(h))
+ goto fail;
+ offset += sizeof(h);
+ sn = s->snapshots + i;
+ sn->l1_table_offset = be64_to_cpu(h.l1_table_offset);
+ sn->l1_size = be32_to_cpu(h.l1_size);
+ sn->vm_state_size = be32_to_cpu(h.vm_state_size);
+ sn->date_sec = be32_to_cpu(h.date_sec);
+ sn->date_nsec = be32_to_cpu(h.date_nsec);
+ sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec);
+ extra_data_size = be32_to_cpu(h.extra_data_size);
+
+ id_str_size = be16_to_cpu(h.id_str_size);
+ name_size = be16_to_cpu(h.name_size);
+
+ offset += extra_data_size;
+
+ sn->id_str = qemu_malloc(id_str_size + 1);
+ if (!sn->id_str)
+ goto fail;
+ if (bdrv_pread(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
+ goto fail;
+ offset += id_str_size;
+ sn->id_str[id_str_size] = '\0';
+
+ sn->name = qemu_malloc(name_size + 1);
+ if (!sn->name)
+ goto fail;
+ if (bdrv_pread(s->hd, offset, sn->name, name_size) != name_size)
+ goto fail;
+ offset += name_size;
+ sn->name[name_size] = '\0';
+ }
+ s->snapshots_size = offset - s->snapshots_offset;
+ return 0;
+ fail:
+ qcow_free_snapshots(bs);
+ return -1;
+}
+
+/* add at the end of the file a new list of snapshots */
+static int qcow_write_snapshots(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ QCowSnapshot *sn;
+ QCowSnapshotHeader h;
+ int i, name_size, id_str_size, snapshots_size;
+ uint64_t data64;
+ uint32_t data32;
+ int64_t offset, snapshots_offset;
+
+ /* compute the size of the snapshots */
+ offset = 0;
+ for(i = 0; i < s->nb_snapshots; i++) {
+ sn = s->snapshots + i;
+ offset = align_offset(offset, 8);
+ offset += sizeof(h);
+ offset += strlen(sn->id_str);
+ offset += strlen(sn->name);
+ }
+ snapshots_size = offset;
+
+ snapshots_offset = alloc_clusters(bs, snapshots_size);
+ offset = snapshots_offset;
+
+ for(i = 0; i < s->nb_snapshots; i++) {
+ sn = s->snapshots + i;
+ memset(&h, 0, sizeof(h));
+ h.l1_table_offset = cpu_to_be64(sn->l1_table_offset);
+ h.l1_size = cpu_to_be32(sn->l1_size);
+ h.vm_state_size = cpu_to_be32(sn->vm_state_size);
+ h.date_sec = cpu_to_be32(sn->date_sec);
+ h.date_nsec = cpu_to_be32(sn->date_nsec);
+ h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec);
+
+ id_str_size = strlen(sn->id_str);
+ name_size = strlen(sn->name);
+ h.id_str_size = cpu_to_be16(id_str_size);
+ h.name_size = cpu_to_be16(name_size);
+ offset = align_offset(offset, 8);
+ if (bdrv_pwrite(s->hd, offset, &h, sizeof(h)) != sizeof(h))
+ goto fail;
+ offset += sizeof(h);
+ if (bdrv_pwrite(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
+ goto fail;
+ offset += id_str_size;
+ if (bdrv_pwrite(s->hd, offset, sn->name, name_size) != name_size)
+ goto fail;
+ offset += name_size;
+ }
+
+ /* update the various header fields */
+ data64 = cpu_to_be64(snapshots_offset);
+ if (bdrv_pwrite(s->hd, offsetof(QCowHeader, snapshots_offset),
+ &data64, sizeof(data64)) != sizeof(data64))
+ goto fail;
+ data32 = cpu_to_be32(s->nb_snapshots);
+ if (bdrv_pwrite(s->hd, offsetof(QCowHeader, nb_snapshots),
+ &data32, sizeof(data32)) != sizeof(data32))
+ goto fail;
+
+ /* free the old snapshot table */
+ free_clusters(bs, s->snapshots_offset, s->snapshots_size);
+ s->snapshots_offset = snapshots_offset;
+ s->snapshots_size = snapshots_size;
+ return 0;
+ fail:
+ return -1;
+}
+
+static void find_new_snapshot_id(BlockDriverState *bs,
+ char *id_str, int id_str_size)
+{
+ BDRVQcowState *s = bs->opaque;
+ QCowSnapshot *sn;
+ int i, id, id_max = 0;
+
+ for(i = 0; i < s->nb_snapshots; i++) {
+ sn = s->snapshots + i;
+ id = strtoul(sn->id_str, NULL, 10);
+ if (id > id_max)
+ id_max = id;
+ }
+ snprintf(id_str, id_str_size, "%d", id_max + 1);
+}
+
+static int find_snapshot_by_id(BlockDriverState *bs, const char *id_str)
+{
+ BDRVQcowState *s = bs->opaque;
+ int i;
+
+ for(i = 0; i < s->nb_snapshots; i++) {
+ if (!strcmp(s->snapshots[i].id_str, id_str))
+ return i;
+ }
+ return -1;
+}
+
+static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name)
+{
+ BDRVQcowState *s = bs->opaque;
+ int i, ret;
+
+ ret = find_snapshot_by_id(bs, name);
+ if (ret >= 0)
+ return ret;
+ for(i = 0; i < s->nb_snapshots; i++) {
+ if (!strcmp(s->snapshots[i].name, name))
+ return i;
+ }
+ return -1;
+}
+
+/* if no id is provided, a new one is constructed */
+static int qcow_snapshot_create(BlockDriverState *bs,
+ QEMUSnapshotInfo *sn_info)
+{
+ BDRVQcowState *s = bs->opaque;
+ QCowSnapshot *snapshots1, sn1, *sn = &sn1;
+ int i, ret;
+ uint64_t *l1_table = NULL;
+
+ memset(sn, 0, sizeof(*sn));
+
+ if (sn_info->id_str[0] == '\0') {
+ /* compute a new id */
+ find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
+ }
+
+ /* check that the ID is unique */
+ if (find_snapshot_by_id(bs, sn_info->id_str) >= 0)
+ return -ENOENT;
+
+ sn->id_str = qemu_strdup(sn_info->id_str);
+ if (!sn->id_str)
+ goto fail;
+ sn->name = qemu_strdup(sn_info->name);
+ if (!sn->name)
+ goto fail;
+ sn->vm_state_size = sn_info->vm_state_size;
+ sn->date_sec = sn_info->date_sec;
+ sn->date_nsec = sn_info->date_nsec;
+ sn->vm_clock_nsec = sn_info->vm_clock_nsec;
+
+ ret = update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1);
+ if (ret < 0)
+ goto fail;
+
+ /* create the L1 table of the snapshot */
+ sn->l1_table_offset = alloc_clusters(bs, s->l1_size * sizeof(uint64_t));
+ sn->l1_size = s->l1_size;
+
+ l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
+ if (!l1_table)
+ goto fail;
+ for(i = 0; i < s->l1_size; i++) {
+ l1_table[i] = cpu_to_be64(s->l1_table[i]);
+ }
+ if (bdrv_pwrite(s->hd, sn->l1_table_offset,
+ l1_table, s->l1_size * sizeof(uint64_t)) !=
+ (s->l1_size * sizeof(uint64_t)))
+ goto fail;
+ qemu_free(l1_table);
+ l1_table = NULL;
+
+ snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot));
+ if (!snapshots1)
+ goto fail;
+ memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));
+ s->snapshots = snapshots1;
+ s->snapshots[s->nb_snapshots++] = *sn;
+
+ if (qcow_write_snapshots(bs) < 0)
+ goto fail;
+#ifdef DEBUG_ALLOC
+ check_refcounts(bs);
+#endif
+ return 0;
+ fail:
+ qemu_free(sn->name);
+ qemu_free(l1_table);
+ return -1;
+}
+
+/* copy the snapshot 'snapshot_name' into the current disk image */
+static int qcow_snapshot_goto(BlockDriverState *bs,
+ const char *snapshot_id)
+{
+ BDRVQcowState *s = bs->opaque;
+ QCowSnapshot *sn;
+ int i, snapshot_index, l1_size2;
+
+ snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
+ if (snapshot_index < 0)
+ return -ENOENT;
+ sn = &s->snapshots[snapshot_index];
+
+ if (update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, -1) < 0)
+ goto fail;
+
+ if (grow_l1_table(bs, sn->l1_size) < 0)
+ goto fail;
+
+ s->l1_size = sn->l1_size;
+ l1_size2 = s->l1_size * sizeof(uint64_t);
+ /* copy the snapshot l1 table to the current l1 table */
+ if (bdrv_pread(s->hd, sn->l1_table_offset,
+ s->l1_table, l1_size2) != l1_size2)
+ goto fail;
+ if (bdrv_pwrite(s->hd, s->l1_table_offset,
+ s->l1_table, l1_size2) != l1_size2)
+ goto fail;
+ for(i = 0;i < s->l1_size; i++) {
+ be64_to_cpus(&s->l1_table[i]);
+ }
+
+ if (update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1) < 0)
+ goto fail;
+
+#ifdef DEBUG_ALLOC
+ check_refcounts(bs);
+#endif
+ return 0;
+ fail:
+ return -EIO;
+}
+
+static int qcow_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
+{
+ BDRVQcowState *s = bs->opaque;
+ QCowSnapshot *sn;
+ int snapshot_index, ret;
+
+ snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
+ if (snapshot_index < 0)
+ return -ENOENT;
+ sn = &s->snapshots[snapshot_index];
+
+ ret = update_snapshot_refcount(bs, sn->l1_table_offset, sn->l1_size, -1);
+ if (ret < 0)
+ return ret;
+ /* must update the copied flag on the current cluster offsets */
+ ret = update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
+ if (ret < 0)
+ return ret;
+ free_clusters(bs, sn->l1_table_offset, sn->l1_size * sizeof(uint64_t));
+
+ qemu_free(sn->id_str);
+ qemu_free(sn->name);
+ memmove(sn, sn + 1, (s->nb_snapshots - snapshot_index - 1) * sizeof(*sn));
+ s->nb_snapshots--;
+ ret = qcow_write_snapshots(bs);
+ if (ret < 0) {
+ /* XXX: restore snapshot if error ? */
+ return ret;
+ }
+#ifdef DEBUG_ALLOC
+ check_refcounts(bs);
+#endif
+ return 0;
+}
+
+static int qcow_snapshot_list(BlockDriverState *bs,
+ QEMUSnapshotInfo **psn_tab)
+{
+ BDRVQcowState *s = bs->opaque;
+ QEMUSnapshotInfo *sn_tab, *sn_info;
+ QCowSnapshot *sn;
+ int i;
+
+ sn_tab = qemu_mallocz(s->nb_snapshots * sizeof(QEMUSnapshotInfo));
+ if (!sn_tab)
+ goto fail;
+ for(i = 0; i < s->nb_snapshots; i++) {
+ sn_info = sn_tab + i;
+ sn = s->snapshots + i;
+ pstrcpy(sn_info->id_str, sizeof(sn_info->id_str),
+ sn->id_str);
+ pstrcpy(sn_info->name, sizeof(sn_info->name),
+ sn->name);
+ sn_info->vm_state_size = sn->vm_state_size;
+ sn_info->date_sec = sn->date_sec;
+ sn_info->date_nsec = sn->date_nsec;
+ sn_info->vm_clock_nsec = sn->vm_clock_nsec;
+ }
+ *psn_tab = sn_tab;
+ return s->nb_snapshots;
+ fail:
+ qemu_free(sn_tab);
+ *psn_tab = NULL;
+ return -ENOMEM;
+}
+
+/*********************************************************/
+/* refcount handling */
+
+static int refcount_init(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ int ret, refcount_table_size2, i;
+
+ s->refcount_block_cache = qemu_malloc(s->cluster_size);
+ if (!s->refcount_block_cache)
+ goto fail;
+ refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t);
+ s->refcount_table = qemu_malloc(refcount_table_size2);
+ if (!s->refcount_table)
+ goto fail;
+ if (s->refcount_table_size > 0) {
+ ret = bdrv_pread(s->hd, s->refcount_table_offset,
+ s->refcount_table, refcount_table_size2);
+ if (ret != refcount_table_size2)
+ goto fail;
+ for(i = 0; i < s->refcount_table_size; i++)
+ be64_to_cpus(&s->refcount_table[i]);
+ }
+ return 0;
+ fail:
+ return -ENOMEM;
+}
+
+static void refcount_close(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ qemu_free(s->refcount_block_cache);
+ qemu_free(s->refcount_table);
+}
+
+
+static int load_refcount_block(BlockDriverState *bs,
+ int64_t refcount_block_offset)
+{
+ BDRVQcowState *s = bs->opaque;
+ int ret;
+ ret = bdrv_pread(s->hd, refcount_block_offset, s->refcount_block_cache,
+ s->cluster_size);
+ if (ret != s->cluster_size)
+ return -EIO;
+ s->refcount_block_cache_offset = refcount_block_offset;
+ return 0;
+}
+
+static int get_refcount(BlockDriverState *bs, int64_t cluster_index)
+{
+ BDRVQcowState *s = bs->opaque;
+ int refcount_table_index, block_index;
+ int64_t refcount_block_offset;
+
+ refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
+ if (refcount_table_index >= s->refcount_table_size)
+ return 0;
+ refcount_block_offset = s->refcount_table[refcount_table_index];
+ if (!refcount_block_offset)
+ return 0;
+ if (refcount_block_offset != s->refcount_block_cache_offset) {
+ /* better than nothing: return allocated if read error */
+ if (load_refcount_block(bs, refcount_block_offset) < 0)
+ return 1;
+ }
+ block_index = cluster_index &
+ ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
+ return be16_to_cpu(s->refcount_block_cache[block_index]);
+}
+
+/* return < 0 if error */
+static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size)
+{
+ BDRVQcowState *s = bs->opaque;
+ int i, nb_clusters;
+
+ nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
+ for(;;) {
+ if (get_refcount(bs, s->free_cluster_index) == 0) {
+ s->free_cluster_index++;
+ for(i = 1; i < nb_clusters; i++) {
+ if (get_refcount(bs, s->free_cluster_index) != 0)
+ goto not_found;
+ s->free_cluster_index++;
+ }
+#ifdef DEBUG_ALLOC2
+ printf("alloc_clusters: size=%lld -> %lld\n",
+ size,
+ (s->free_cluster_index - nb_clusters) << s->cluster_bits);
+#endif
+ return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
+ } else {
+ not_found:
+ s->free_cluster_index++;
+ }
+ }
+}
+
+static int64_t alloc_clusters(BlockDriverState *bs, int64_t size)
+{
+ int64_t offset;
+
+ offset = alloc_clusters_noref(bs, size);
+ update_refcount(bs, offset, size, 1);
+ return offset;
+}
+
+/* only used to allocate compressed sectors. We try to allocate
+ contiguous sectors. size must be <= cluster_size */
+static int64_t alloc_bytes(BlockDriverState *bs, int size)
+{
+ BDRVQcowState *s = bs->opaque;
+ int64_t offset, cluster_offset;
+ int free_in_cluster;
+
+ assert(size > 0 && size <= s->cluster_size);
+ if (s->free_byte_offset == 0) {
+ s->free_byte_offset = alloc_clusters(bs, s->cluster_size);
+ }
+ redo:
+ free_in_cluster = s->cluster_size -
+ (s->free_byte_offset & (s->cluster_size - 1));
+ if (size <= free_in_cluster) {
+ /* enough space in current cluster */
+ offset = s->free_byte_offset;
+ s->free_byte_offset += size;
+ free_in_cluster -= size;
+ if (free_in_cluster == 0)
+ s->free_byte_offset = 0;
+ if ((offset & (s->cluster_size - 1)) != 0)
+ update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
+ } else {
+ offset = alloc_clusters(bs, s->cluster_size);
+ cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1);
+ if ((cluster_offset + s->cluster_size) == offset) {
+ /* we are lucky: contiguous data */
+ offset = s->free_byte_offset;
+ update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
+ s->free_byte_offset += size;
+ } else {
+ s->free_byte_offset = offset;
+ goto redo;
+ }
+ }
+ return offset;
+}
+
+static void free_clusters(BlockDriverState *bs,
+ int64_t offset, int64_t size)
+{
+ update_refcount(bs, offset, size, -1);
+}
+
+static int grow_refcount_table(BlockDriverState *bs, int min_size)
+{
+ BDRVQcowState *s = bs->opaque;
+ int new_table_size, new_table_size2, refcount_table_clusters, i, ret;
+ uint64_t *new_table;
+ int64_t table_offset;
+ uint64_t data64;
+ uint32_t data32;
+
+ if (min_size <= s->refcount_table_size)
+ return 0;
+ /* compute new table size */
+ refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
+ for(;;) {
+ if (refcount_table_clusters == 0) {
+ refcount_table_clusters = 1;
+ } else {
+ refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2;
+ }
+ new_table_size = refcount_table_clusters << (s->cluster_bits - 3);
+ if (min_size <= new_table_size)
+ break;
+ }
+
+ new_table_size2 = new_table_size * sizeof(uint64_t);
+ new_table = qemu_mallocz(new_table_size2);
+ if (!new_table)
+ return -ENOMEM;
+ memcpy(new_table, s->refcount_table,
+ s->refcount_table_size * sizeof(uint64_t));
+ for(i = 0; i < s->refcount_table_size; i++)
+ cpu_to_be64s(&new_table[i]);
+ /* Note: we cannot update the refcount now to avoid recursion */
+ table_offset = alloc_clusters_noref(bs, new_table_size2);
+ ret = bdrv_pwrite(s->hd, table_offset, new_table, new_table_size2);
+ if (ret != new_table_size2)
+ goto fail;
+ for(i = 0; i < s->refcount_table_size; i++)
+ be64_to_cpus(&new_table[i]);
+
+ data64 = cpu_to_be64(table_offset);
+ if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset),
+ &data64, sizeof(data64)) != sizeof(data64))
+ goto fail;
+ data32 = cpu_to_be32(refcount_table_clusters);
+ if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_clusters),
+ &data32, sizeof(data32)) != sizeof(data32))
+ goto fail;
+ qemu_free(s->refcount_table);
+ s->refcount_table = new_table;
+ s->refcount_table_size = new_table_size;
+
+ update_refcount(bs, table_offset, new_table_size2, 1);
+ return 0;
+ fail:
+ free_clusters(bs, table_offset, new_table_size2);
+ qemu_free(new_table);
+ return -EIO;
+}
+
+/* addend must be 1 or -1 */
+/* XXX: cache several refcount block clusters ? */
+static int update_cluster_refcount(BlockDriverState *bs,
+ int64_t cluster_index,
+ int addend)
+{
+ BDRVQcowState *s = bs->opaque;
+ int64_t offset, refcount_block_offset;
+ int ret, refcount_table_index, block_index, refcount;
+ uint64_t data64;
+
+ refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
+ if (refcount_table_index >= s->refcount_table_size) {
+ if (addend < 0)
+ return -EINVAL;
+ ret = grow_refcount_table(bs, refcount_table_index + 1);
+ if (ret < 0)
+ return ret;
+ }
+ refcount_block_offset = s->refcount_table[refcount_table_index];
+ if (!refcount_block_offset) {
+ if (addend < 0)
+ return -EINVAL;
+ /* create a new refcount block */
+ /* Note: we cannot update the refcount now to avoid recursion */
+ offset = alloc_clusters_noref(bs, s->cluster_size);
+ memset(s->refcount_block_cache, 0, s->cluster_size);
+ ret = bdrv_pwrite(s->hd, offset, s->refcount_block_cache, s->cluster_size);
+ if (ret != s->cluster_size)
+ return -EINVAL;
+ s->refcount_table[refcount_table_index] = offset;
+ data64 = cpu_to_be64(offset);
+ ret = bdrv_pwrite(s->hd, s->refcount_table_offset +
+ refcount_table_index * sizeof(uint64_t),
+ &data64, sizeof(data64));
+ if (ret != sizeof(data64))
+ return -EINVAL;
+
+ refcount_block_offset = offset;
+ s->refcount_block_cache_offset = offset;
+ update_refcount(bs, offset, s->cluster_size, 1);
+ } else {
+ if (refcount_block_offset != s->refcount_block_cache_offset) {
+ if (load_refcount_block(bs, refcount_block_offset) < 0)
+ return -EIO;
+ }
+ }
+ /* we can update the count and save it */
+ block_index = cluster_index &
+ ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
+ refcount = be16_to_cpu(s->refcount_block_cache[block_index]);
+ refcount += addend;
+ if (refcount < 0 || refcount > 0xffff)
+ return -EINVAL;
+ if (refcount == 0 && cluster_index < s->free_cluster_index) {
+ s->free_cluster_index = cluster_index;
+ }
+ s->refcount_block_cache[block_index] = cpu_to_be16(refcount);
+ if (bdrv_pwrite(s->hd,
+ refcount_block_offset + (block_index << REFCOUNT_SHIFT),
+ &s->refcount_block_cache[block_index], 2) != 2)
+ return -EIO;
+ return refcount;
+}
+
+static void update_refcount(BlockDriverState *bs,
+ int64_t offset, int64_t length,
+ int addend)
+{
+ BDRVQcowState *s = bs->opaque;
+ int64_t start, last, cluster_offset;
+
+#ifdef DEBUG_ALLOC2
+ printf("update_refcount: offset=%lld size=%lld addend=%d\n",
+ offset, length, addend);
+#endif
+ if (length <= 0)
+ return;
+ start = offset & ~(s->cluster_size - 1);
+ last = (offset + length - 1) & ~(s->cluster_size - 1);
+ for(cluster_offset = start; cluster_offset <= last;
+ cluster_offset += s->cluster_size) {
+ update_cluster_refcount(bs, cluster_offset >> s->cluster_bits, addend);
+ }
+}
+
+#ifdef DEBUG_ALLOC
+static void inc_refcounts(BlockDriverState *bs,
+ uint16_t *refcount_table,
+ int refcount_table_size,
+ int64_t offset, int64_t size)
+{
+ BDRVQcowState *s = bs->opaque;
+ int64_t start, last, cluster_offset;
+ int k;
+
+ if (size <= 0)
+ return;
+
+ start = offset & ~(s->cluster_size - 1);
+ last = (offset + size - 1) & ~(s->cluster_size - 1);
+ for(cluster_offset = start; cluster_offset <= last;
+ cluster_offset += s->cluster_size) {
+ k = cluster_offset >> s->cluster_bits;
+ if (k < 0 || k >= refcount_table_size) {
+ printf("ERROR: invalid cluster offset=0x%llx\n", cluster_offset);
+ } else {
+ if (++refcount_table[k] == 0) {
+ printf("ERROR: overflow cluster offset=0x%llx\n", cluster_offset);
+ }
+ }
+ }
+}
+
+static int check_refcounts_l1(BlockDriverState *bs,
+ uint16_t *refcount_table,
+ int refcount_table_size,
+ int64_t l1_table_offset, int l1_size,
+ int check_copied)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2;
+ int l2_size, i, j, nb_csectors, refcount;
+
+ l2_table = NULL;
+ l1_size2 = l1_size * sizeof(uint64_t);
+
+ inc_refcounts(bs, refcount_table, refcount_table_size,
+ l1_table_offset, l1_size2);
+
+ l1_table = qemu_malloc(l1_size2);
+ if (!l1_table)
+ goto fail;
+ if (bdrv_pread(s->hd, l1_table_offset,
+ l1_table, l1_size2) != l1_size2)
+ goto fail;
+ for(i = 0;i < l1_size; i++)
+ be64_to_cpus(&l1_table[i]);
+
+ l2_size = s->l2_size * sizeof(uint64_t);
+ l2_table = qemu_malloc(l2_size);
+ if (!l2_table)
+ goto fail;
+ for(i = 0; i < l1_size; i++) {
+ l2_offset = l1_table[i];
+ if (l2_offset) {
+ if (check_copied) {
+ refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits);
+ if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) {
+ printf("ERROR OFLAG_COPIED: l2_offset=%llx refcount=%d\n",
+ l2_offset, refcount);
+ }
+ }
+ l2_offset &= ~QCOW_OFLAG_COPIED;
+ if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
+ goto fail;
+ for(j = 0; j < s->l2_size; j++) {
+ offset = be64_to_cpu(l2_table[j]);
+ if (offset != 0) {
+ if (offset & QCOW_OFLAG_COMPRESSED) {
+ if (offset & QCOW_OFLAG_COPIED) {
+ printf("ERROR: cluster %lld: copied flag must never be set for compressed clusters\n",
+ offset >> s->cluster_bits);
+ offset &= ~QCOW_OFLAG_COPIED;
+ }
+ nb_csectors = ((offset >> s->csize_shift) &
+ s->csize_mask) + 1;
+ offset &= s->cluster_offset_mask;
+ inc_refcounts(bs, refcount_table,
+ refcount_table_size,
+ offset & ~511, nb_csectors * 512);
+ } else {
+ if (check_copied) {
+ refcount = get_refcount(bs, (offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits);
+ if ((refcount == 1) != ((offset & QCOW_OFLAG_COPIED) != 0)) {
+ printf("ERROR OFLAG_COPIED: offset=%llx refcount=%d\n",
+ offset, refcount);
+ }
+ }
+ offset &= ~QCOW_OFLAG_COPIED;
+ inc_refcounts(bs, refcount_table,
+ refcount_table_size,
+ offset, s->cluster_size);
+ }
+ }
+ }
+ inc_refcounts(bs, refcount_table,
+ refcount_table_size,
+ l2_offset,
+ s->cluster_size);
+ }
+ }
+ qemu_free(l1_table);
+ qemu_free(l2_table);
+ return 0;
+ fail:
+ printf("ERROR: I/O error in check_refcounts_l1\n");
+ qemu_free(l1_table);
+ qemu_free(l2_table);
+ return -EIO;
+}
+
+static void check_refcounts(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ int64_t size;
+ int nb_clusters, refcount1, refcount2, i;
+ QCowSnapshot *sn;
+ uint16_t *refcount_table;
+
+ size = bdrv_getlength(s->hd);
+ nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
+ refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t));
+
+ /* header */
+ inc_refcounts(bs, refcount_table, nb_clusters,
+ 0, s->cluster_size);
+
+ check_refcounts_l1(bs, refcount_table, nb_clusters,
+ s->l1_table_offset, s->l1_size, 1);
+
+ /* snapshots */
+ for(i = 0; i < s->nb_snapshots; i++) {
+ sn = s->snapshots + i;
+ check_refcounts_l1(bs, refcount_table, nb_clusters,
+ sn->l1_table_offset, sn->l1_size, 0);
+ }
+ inc_refcounts(bs, refcount_table, nb_clusters,
+ s->snapshots_offset, s->snapshots_size);
+
+ /* refcount data */
+ inc_refcounts(bs, refcount_table, nb_clusters,
+ s->refcount_table_offset,
+ s->refcount_table_size * sizeof(uint64_t));
+ for(i = 0; i < s->refcount_table_size; i++) {
+ int64_t offset;
+ offset = s->refcount_table[i];
+ if (offset != 0) {
+ inc_refcounts(bs, refcount_table, nb_clusters,
+ offset, s->cluster_size);
+ }
+ }
+
+ /* compare ref counts */
+ for(i = 0; i < nb_clusters; i++) {
+ refcount1 = get_refcount(bs, i);
+ refcount2 = refcount_table[i];
+ if (refcount1 != refcount2)
+ printf("ERROR cluster %d refcount=%d reference=%d\n",
+ i, refcount1, refcount2);
+ }
+
+ qemu_free(refcount_table);
+}
+
+#if 0
+static void dump_refcounts(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ int64_t nb_clusters, k, k1, size;
+ int refcount;
+
+ size = bdrv_getlength(s->hd);
+ nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
+ 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("%lld: refcount=%d nb=%lld\n", k, refcount, k - k1);
+ }
+}
+#endif
+#endif
+
+BlockDriver bdrv_qcow2 = {
+ "qcow2",
+ sizeof(BDRVQcowState),
+ qcow_probe,
+ qcow_open,
+ NULL,
+ NULL,
+ qcow_close,
+ qcow_create,
+ qcow_flush,
+ qcow_is_allocated,
+ qcow_set_key,
+ qcow_make_empty,
+
+ .bdrv_aio_new = qcow_aio_new,
+ .bdrv_aio_read = qcow_aio_read,
+ .bdrv_aio_write = qcow_aio_write,
+ .bdrv_aio_cancel = qcow_aio_cancel,
+ .bdrv_aio_delete = qcow_aio_delete,
+ .bdrv_write_compressed = qcow_write_compressed,
+
+ .bdrv_snapshot_create = qcow_snapshot_create,
+ .bdrv_snapshot_goto = qcow_snapshot_goto,
+ .bdrv_snapshot_delete = qcow_snapshot_delete,
+ .bdrv_snapshot_list = qcow_snapshot_list,
+ .bdrv_get_info = qcow_get_info,
+};
projects / qemu / commitdiff