| /* |
| * 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_int.h" |
| #include "block/qcow2.h" |
| |
| int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int new_l1_size, new_l1_size2, ret, i; |
| uint64_t *new_l1_table; |
| int64_t new_l1_table_offset; |
| uint8_t data[12]; |
| |
| if (min_size <= s->l1_size) |
| return 0; |
| |
| 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; |
| } |
| } |
| |
| #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(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_free(new_l1_table); |
| return new_l1_table_offset; |
| } |
| |
| ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| 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); |
| cpu_to_be64wu((uint64_t*)(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_free(s->l1_table); |
| qcow2_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(new_l1_table); |
| qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2); |
| 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) |
| static int write_l1_entry(BlockDriverState *bs, int l1_index) |
| { |
| BDRVQcowState *s = bs->opaque; |
| uint64_t buf[L1_ENTRIES_PER_SECTOR]; |
| 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; i++) { |
| buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]); |
| } |
| |
| 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; |
| int64_t l2_offset; |
| int ret; |
| |
| old_l2_offset = s->l1_table[l1_index]; |
| |
| /* allocate a new l2 entry */ |
| |
| l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t)); |
| if (l2_offset < 0) { |
| return l2_offset; |
| } |
| |
| ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| /* allocate a new entry in the l2 cache */ |
| |
| ret = qcow2_cache_get_empty(bs, s->l2_table_cache, l2_offset, (void**) table); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| l2_table = *table; |
| |
| if (old_l2_offset == 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, |
| (void**) &old_table); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| memcpy(l2_table, old_table, s->cluster_size); |
| |
| ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &old_table); |
| if (ret < 0) { |
| goto fail; |
| } |
| } |
| |
| /* write the l2 table to the file */ |
| BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE); |
| |
| qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); |
| ret = qcow2_cache_flush(bs, s->l2_table_cache); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| /* update the L1 entry */ |
| s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED; |
| ret = write_l1_entry(bs, l1_index); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| *table = l2_table; |
| return 0; |
| |
| fail: |
| qcow2_cache_put(bs, s->l2_table_cache, (void**) table); |
| s->l1_table[l1_index] = old_l2_offset; |
| return ret; |
| } |
| |
| static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size, |
| uint64_t *l2_table, uint64_t start, uint64_t mask) |
| { |
| int i; |
| uint64_t offset = be64_to_cpu(l2_table[0]) & ~mask; |
| |
| if (!offset) |
| return 0; |
| |
| for (i = start; i < start + nb_clusters; i++) |
| if (offset + (uint64_t) i * cluster_size != (be64_to_cpu(l2_table[i]) & ~mask)) |
| break; |
| |
| return (i - start); |
| } |
| |
| static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table) |
| { |
| int i = 0; |
| |
| while(nb_clusters-- && l2_table[i] == 0) |
| i++; |
| |
| return i; |
| } |
| |
| /* The crypt function is compatible with the linux cryptoloop |
| algorithm for < 4 GB images. NOTE: out_buf == in_buf is |
| supported */ |
| void qcow2_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 qcow2_read(BlockDriverState *bs, int64_t sector_num, |
| uint8_t *buf, int nb_sectors) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int ret, index_in_cluster, n, n1; |
| uint64_t cluster_offset; |
| struct iovec iov; |
| QEMUIOVector qiov; |
| |
| while (nb_sectors > 0) { |
| n = nb_sectors; |
| |
| ret = qcow2_get_cluster_offset(bs, sector_num << 9, &n, |
| &cluster_offset); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| index_in_cluster = sector_num & (s->cluster_sectors - 1); |
| if (!cluster_offset) { |
| if (bs->backing_hd) { |
| /* read from the base image */ |
| iov.iov_base = buf; |
| iov.iov_len = n * 512; |
| qemu_iovec_init_external(&qiov, &iov, 1); |
| |
| n1 = qcow2_backing_read1(bs->backing_hd, &qiov, sector_num, n); |
| if (n1 > 0) { |
| BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING); |
| ret = bdrv_read(bs->backing_hd, sector_num, buf, n1); |
| if (ret < 0) |
| return -1; |
| } |
| } else { |
| memset(buf, 0, 512 * n); |
| } |
| } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { |
| if (qcow2_decompress_cluster(bs, cluster_offset) < 0) |
| return -1; |
| memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n); |
| } else { |
| BLKDBG_EVENT(bs->file, BLKDBG_READ); |
| ret = bdrv_pread(bs->file, cluster_offset + index_in_cluster * 512, buf, n * 512); |
| if (ret != n * 512) |
| return -1; |
| if (s->crypt_method) { |
| qcow2_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 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; |
| BLKDBG_EVENT(bs->file, BLKDBG_COW_READ); |
| ret = qcow2_read(bs, start_sect + n_start, s->cluster_data, n); |
| if (ret < 0) |
| return ret; |
| if (s->crypt_method) { |
| qcow2_encrypt_sectors(s, start_sect + n_start, |
| s->cluster_data, |
| s->cluster_data, n, 1, |
| &s->aes_encrypt_key); |
| } |
| BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE); |
| ret = bdrv_write(bs->file, (cluster_offset >> 9) + n_start, |
| s->cluster_data, n); |
| if (ret < 0) |
| return ret; |
| return 0; |
| } |
| |
| |
| /* |
| * 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 clusters we'd like to |
| * access following offset. |
| * |
| * on exit, *num is the number of contiguous clusters we can read. |
| * |
| * Return 0, if the offset is found |
| * Return -errno, otherwise. |
| * |
| */ |
| |
| int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, |
| int *num, uint64_t *cluster_offset) |
| { |
| BDRVQcowState *s = bs->opaque; |
| unsigned int l1_index, l2_index; |
| uint64_t 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) |
| goto out; |
| |
| l2_offset = s->l1_table[l1_index]; |
| |
| /* seek the l2 table of the given l2 offset */ |
| |
| if (!l2_offset) |
| goto out; |
| |
| /* load the l2 table in memory */ |
| |
| l2_offset &= ~QCOW_OFLAG_COPIED; |
| 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); |
| |
| if (!*cluster_offset) { |
| /* how many empty clusters ? */ |
| c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]); |
| } else { |
| /* how many allocated clusters ? */ |
| c = count_contiguous_clusters(nb_clusters, s->cluster_size, |
| &l2_table[l2_index], 0, QCOW_OFLAG_COPIED); |
| } |
| |
| 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; |
| |
| *cluster_offset &=~QCOW_OFLAG_COPIED; |
| return 0; |
| } |
| |
| /* |
| * 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, |
| uint64_t *new_l2_offset, |
| int *new_l2_index) |
| { |
| BDRVQcowState *s = bs->opaque; |
| unsigned int l1_index, l2_index; |
| uint64_t 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; |
| } |
| } |
| l2_offset = s->l1_table[l1_index]; |
| |
| /* seek the l2 table of the given l2 offset */ |
| |
| if (l2_offset & QCOW_OFLAG_COPIED) { |
| /* load the l2 table in memory */ |
| l2_offset &= ~QCOW_OFLAG_COPIED; |
| 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)); |
| } |
| l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED; |
| } |
| |
| /* 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_offset = l2_offset; |
| *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_offset, *l2_table; |
| int64_t cluster_offset; |
| int nb_csectors; |
| |
| ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index); |
| if (ret < 0) { |
| return 0; |
| } |
| |
| cluster_offset = be64_to_cpu(l2_table[l2_index]); |
| if (cluster_offset & QCOW_OFLAG_COPIED) |
| return cluster_offset & ~QCOW_OFLAG_COPIED; |
| |
| if (cluster_offset) |
| qcow2_free_any_clusters(bs, cluster_offset, 1); |
| |
| 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(s->l2_table_cache, l2_table); |
| l2_table[l2_index] = cpu_to_be64(cluster_offset); |
| ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
| if (ret < 0) { |
| return 0; |
| } |
| |
| return cluster_offset; |
| } |
| |
| 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, start_sect, l2_offset, *l2_table; |
| uint64_t cluster_offset = m->cluster_offset; |
| bool cow = false; |
| |
| if (m->nb_clusters == 0) |
| return 0; |
| |
| old_cluster = qemu_malloc(m->nb_clusters * sizeof(uint64_t)); |
| |
| /* copy content of unmodified sectors */ |
| start_sect = (m->offset & ~(s->cluster_size - 1)) >> 9; |
| if (m->n_start) { |
| cow = true; |
| ret = copy_sectors(bs, start_sect, cluster_offset, 0, m->n_start); |
| if (ret < 0) |
| goto err; |
| } |
| |
| if (m->nb_available & (s->cluster_sectors - 1)) { |
| uint64_t end = m->nb_available & ~(uint64_t)(s->cluster_sectors - 1); |
| cow = true; |
| ret = copy_sectors(bs, start_sect + end, cluster_offset + (end << 9), |
| m->nb_available - end, s->cluster_sectors); |
| if (ret < 0) |
| goto err; |
| } |
| |
| /* |
| * Update L2 table. |
| * |
| * 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. |
| */ |
| if (cow) { |
| qcow2_cache_depends_on_flush(s->l2_table_cache); |
| } |
| |
| qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache); |
| ret = get_cluster_table(bs, m->offset, &l2_table, &l2_offset, &l2_index); |
| if (ret < 0) { |
| goto err; |
| } |
| qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); |
| |
| 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); |
| } |
| |
| |
| ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
| if (ret < 0) { |
| goto err; |
| } |
| |
| /* |
| * 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. |
| */ |
| if (j != 0) { |
| for (i = 0; i < j; i++) { |
| qcow2_free_any_clusters(bs, |
| be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1); |
| } |
| } |
| |
| ret = 0; |
| err: |
| qemu_free(old_cluster); |
| return ret; |
| } |
| |
| /* |
| * alloc_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 cluster. |
| * |
| * If the cluster was already allocated, m->nb_clusters is set to 0, |
| * m->depends_on is set to NULL and the 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. This may be 0 if the request |
| * conflict with another write request in flight; in this case, m->depends_on |
| * is set and the remaining fields of m are meaningless. |
| * |
| * If m->nb_clusters is non-zero, the other fields of m are valid and contain |
| * information about the first allocated cluster. |
| * |
| * Return 0 on success and -errno in error cases |
| */ |
| int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, |
| int n_start, int n_end, int *num, QCowL2Meta *m) |
| { |
| BDRVQcowState *s = bs->opaque; |
| int l2_index, ret; |
| uint64_t l2_offset, *l2_table; |
| int64_t cluster_offset; |
| unsigned int nb_clusters, i = 0; |
| QCowL2Meta *old_alloc; |
| |
| ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| nb_clusters = size_to_clusters(s, n_end << 9); |
| |
| nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); |
| |
| cluster_offset = be64_to_cpu(l2_table[l2_index]); |
| |
| /* We keep all QCOW_OFLAG_COPIED clusters */ |
| |
| if (cluster_offset & QCOW_OFLAG_COPIED) { |
| nb_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size, |
| &l2_table[l2_index], 0, 0); |
| |
| cluster_offset &= ~QCOW_OFLAG_COPIED; |
| m->nb_clusters = 0; |
| m->depends_on = NULL; |
| |
| goto out; |
| } |
| |
| /* for the moment, multiple compressed clusters are not managed */ |
| |
| if (cluster_offset & QCOW_OFLAG_COMPRESSED) |
| nb_clusters = 1; |
| |
| /* how many available clusters ? */ |
| |
| while (i < nb_clusters) { |
| i += count_contiguous_clusters(nb_clusters - i, s->cluster_size, |
| &l2_table[l2_index], i, 0); |
| if ((i >= nb_clusters) || be64_to_cpu(l2_table[l2_index + i])) { |
| break; |
| } |
| |
| i += count_contiguous_free_clusters(nb_clusters - i, |
| &l2_table[l2_index + i]); |
| if (i >= nb_clusters) { |
| break; |
| } |
| |
| cluster_offset = be64_to_cpu(l2_table[l2_index + i]); |
| |
| if ((cluster_offset & QCOW_OFLAG_COPIED) || |
| (cluster_offset & QCOW_OFLAG_COMPRESSED)) |
| break; |
| } |
| assert(i <= nb_clusters); |
| nb_clusters = 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. |
| */ |
| QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) { |
| |
| uint64_t end_offset = offset + nb_clusters * s->cluster_size; |
| uint64_t old_offset = old_alloc->offset; |
| uint64_t old_end_offset = old_alloc->offset + |
| old_alloc->nb_clusters * s->cluster_size; |
| |
| if (end_offset < old_offset || offset > old_end_offset) { |
| /* No intersection */ |
| } else { |
| if (offset < old_offset) { |
| /* Stop at the start of a running allocation */ |
| nb_clusters = (old_offset - offset) >> s->cluster_bits; |
| } else { |
| nb_clusters = 0; |
| } |
| |
| if (nb_clusters == 0) { |
| /* Set dependency and wait for a callback */ |
| m->depends_on = old_alloc; |
| m->nb_clusters = 0; |
| *num = 0; |
| ret = 0; |
| goto fail; |
| } |
| } |
| } |
| |
| if (!nb_clusters) { |
| abort(); |
| } |
| |
| QLIST_INSERT_HEAD(&s->cluster_allocs, m, next_in_flight); |
| |
| /* allocate a new cluster */ |
| |
| cluster_offset = qcow2_alloc_clusters(bs, nb_clusters * s->cluster_size); |
| if (cluster_offset < 0) { |
| QLIST_REMOVE(m, next_in_flight); |
| ret = cluster_offset; |
| goto fail; |
| } |
| |
| /* save info needed for meta data update */ |
| m->offset = offset; |
| m->n_start = n_start; |
| m->nb_clusters = nb_clusters; |
| |
| out: |
| ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| m->nb_available = MIN(nb_clusters << (s->cluster_bits - 9), n_end); |
| m->cluster_offset = cluster_offset; |
| |
| *num = m->nb_available - n_start; |
| |
| return 0; |
| |
| fail: |
| qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
| return ret; |
| } |
| |
| 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) |
| { |
| BDRVQcowState *s = bs->opaque; |
| uint64_t l2_offset, *l2_table; |
| int l2_index; |
| int ret; |
| int i; |
| |
| ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &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]); |
| old_offset &= ~QCOW_OFLAG_COPIED; |
| |
| if (old_offset == 0) { |
| continue; |
| } |
| |
| /* First remove L2 entries */ |
| qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); |
| l2_table[l2_index + i] = cpu_to_be64(0); |
| |
| /* Then decrease the refcount */ |
| qcow2_free_any_clusters(bs, old_offset, 1); |
| } |
| |
| ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| return nb_clusters; |
| } |
| |
| int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset, |
| int nb_sectors) |
| { |
| 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 &= ~(s->cluster_size - 1); |
| |
| if (offset > end_offset) { |
| return 0; |
| } |
| |
| nb_clusters = size_to_clusters(s, end_offset - offset); |
| |
| /* Each L2 table is handled by its own loop iteration */ |
| while (nb_clusters > 0) { |
| ret = discard_single_l2(bs, offset, nb_clusters); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| nb_clusters -= ret; |
| offset += (ret * s->cluster_size); |
| } |
| |
| return 0; |
| } |
