| /* |
| * Block driver for the QCOW version 2 format |
| * |
| * Copyright (c) 2004-2006 Fabrice Bellard |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| * THE SOFTWARE. |
| */ |
| |
| #include "qemu-common.h" |
| #include "block/block_int.h" |
| #include "block/qcow2.h" |
| #include "qemu/range.h" |
| |
| static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size); |
| static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
| int64_t offset, int64_t length, uint64_t addend, |
| bool decrease, enum qcow2_discard_type type); |
| |
| static uint64_t get_refcount_ro0(const void *refcount_array, uint64_t index); |
| static uint64_t get_refcount_ro1(const void *refcount_array, uint64_t index); |
| static uint64_t get_refcount_ro2(const void *refcount_array, uint64_t index); |
| static uint64_t get_refcount_ro3(const void *refcount_array, uint64_t index); |
| static uint64_t get_refcount_ro4(const void *refcount_array, uint64_t index); |
| static uint64_t get_refcount_ro5(const void *refcount_array, uint64_t index); |
| static uint64_t get_refcount_ro6(const void *refcount_array, uint64_t index); |
| |
| static void set_refcount_ro0(void *refcount_array, uint64_t index, |
| uint64_t value); |
| static void set_refcount_ro1(void *refcount_array, uint64_t index, |
| uint64_t value); |
| static void set_refcount_ro2(void *refcount_array, uint64_t index, |
| uint64_t value); |
| static void set_refcount_ro3(void *refcount_array, uint64_t index, |
| uint64_t value); |
| static void set_refcount_ro4(void *refcount_array, uint64_t index, |
| uint64_t value); |
| static void set_refcount_ro5(void *refcount_array, uint64_t index, |
| uint64_t value); |
| static void set_refcount_ro6(void *refcount_array, uint64_t index, |
| uint64_t value); |
| |
| |
| static Qcow2GetRefcountFunc *const get_refcount_funcs[] = { |
| &get_refcount_ro0, |
| &get_refcount_ro1, |
| &get_refcount_ro2, |
| &get_refcount_ro3, |
| &get_refcount_ro4, |
| &get_refcount_ro5, |
| &get_refcount_ro6 |
| }; |
| |
| static Qcow2SetRefcountFunc *const set_refcount_funcs[] = { |
| &set_refcount_ro0, |
| &set_refcount_ro1, |
| &set_refcount_ro2, |
| &set_refcount_ro3, |
| &set_refcount_ro4, |
| &set_refcount_ro5, |
| &set_refcount_ro6 |
| }; |
| |
| |
| /*********************************************************/ |
| /* refcount handling */ |
| |
| int qcow2_refcount_init(BlockDriverState *bs) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| unsigned int refcount_table_size2, i; |
| int ret; |
| |
| assert(s->refcount_order >= 0 && s->refcount_order <= 6); |
| |
| s->get_refcount = get_refcount_funcs[s->refcount_order]; |
| s->set_refcount = set_refcount_funcs[s->refcount_order]; |
| |
| assert(s->refcount_table_size <= INT_MAX / sizeof(uint64_t)); |
| refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t); |
| s->refcount_table = g_try_malloc(refcount_table_size2); |
| |
| if (s->refcount_table_size > 0) { |
| if (s->refcount_table == NULL) { |
| ret = -ENOMEM; |
| goto fail; |
| } |
| BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_LOAD); |
| ret = bdrv_pread(bs->file->bs, s->refcount_table_offset, |
| s->refcount_table, refcount_table_size2); |
| if (ret < 0) { |
| goto fail; |
| } |
| for(i = 0; i < s->refcount_table_size; i++) |
| be64_to_cpus(&s->refcount_table[i]); |
| } |
| return 0; |
| fail: |
| return ret; |
| } |
| |
| void qcow2_refcount_close(BlockDriverState *bs) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| g_free(s->refcount_table); |
| } |
| |
| |
| static uint64_t get_refcount_ro0(const void *refcount_array, uint64_t index) |
| { |
| return (((const uint8_t *)refcount_array)[index / 8] >> (index % 8)) & 0x1; |
| } |
| |
| static void set_refcount_ro0(void *refcount_array, uint64_t index, |
| uint64_t value) |
| { |
| assert(!(value >> 1)); |
| ((uint8_t *)refcount_array)[index / 8] &= ~(0x1 << (index % 8)); |
| ((uint8_t *)refcount_array)[index / 8] |= value << (index % 8); |
| } |
| |
| static uint64_t get_refcount_ro1(const void *refcount_array, uint64_t index) |
| { |
| return (((const uint8_t *)refcount_array)[index / 4] >> (2 * (index % 4))) |
| & 0x3; |
| } |
| |
| static void set_refcount_ro1(void *refcount_array, uint64_t index, |
| uint64_t value) |
| { |
| assert(!(value >> 2)); |
| ((uint8_t *)refcount_array)[index / 4] &= ~(0x3 << (2 * (index % 4))); |
| ((uint8_t *)refcount_array)[index / 4] |= value << (2 * (index % 4)); |
| } |
| |
| static uint64_t get_refcount_ro2(const void *refcount_array, uint64_t index) |
| { |
| return (((const uint8_t *)refcount_array)[index / 2] >> (4 * (index % 2))) |
| & 0xf; |
| } |
| |
| static void set_refcount_ro2(void *refcount_array, uint64_t index, |
| uint64_t value) |
| { |
| assert(!(value >> 4)); |
| ((uint8_t *)refcount_array)[index / 2] &= ~(0xf << (4 * (index % 2))); |
| ((uint8_t *)refcount_array)[index / 2] |= value << (4 * (index % 2)); |
| } |
| |
| static uint64_t get_refcount_ro3(const void *refcount_array, uint64_t index) |
| { |
| return ((const uint8_t *)refcount_array)[index]; |
| } |
| |
| static void set_refcount_ro3(void *refcount_array, uint64_t index, |
| uint64_t value) |
| { |
| assert(!(value >> 8)); |
| ((uint8_t *)refcount_array)[index] = value; |
| } |
| |
| static uint64_t get_refcount_ro4(const void *refcount_array, uint64_t index) |
| { |
| return be16_to_cpu(((const uint16_t *)refcount_array)[index]); |
| } |
| |
| static void set_refcount_ro4(void *refcount_array, uint64_t index, |
| uint64_t value) |
| { |
| assert(!(value >> 16)); |
| ((uint16_t *)refcount_array)[index] = cpu_to_be16(value); |
| } |
| |
| static uint64_t get_refcount_ro5(const void *refcount_array, uint64_t index) |
| { |
| return be32_to_cpu(((const uint32_t *)refcount_array)[index]); |
| } |
| |
| static void set_refcount_ro5(void *refcount_array, uint64_t index, |
| uint64_t value) |
| { |
| assert(!(value >> 32)); |
| ((uint32_t *)refcount_array)[index] = cpu_to_be32(value); |
| } |
| |
| static uint64_t get_refcount_ro6(const void *refcount_array, uint64_t index) |
| { |
| return be64_to_cpu(((const uint64_t *)refcount_array)[index]); |
| } |
| |
| static void set_refcount_ro6(void *refcount_array, uint64_t index, |
| uint64_t value) |
| { |
| ((uint64_t *)refcount_array)[index] = cpu_to_be64(value); |
| } |
| |
| |
| static int load_refcount_block(BlockDriverState *bs, |
| int64_t refcount_block_offset, |
| void **refcount_block) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int ret; |
| |
| BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD); |
| ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset, |
| refcount_block); |
| |
| return ret; |
| } |
| |
| /* |
| * Retrieves the refcount of the cluster given by its index and stores it in |
| * *refcount. Returns 0 on success and -errno on failure. |
| */ |
| int qcow2_get_refcount(BlockDriverState *bs, int64_t cluster_index, |
| uint64_t *refcount) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| uint64_t refcount_table_index, block_index; |
| int64_t refcount_block_offset; |
| int ret; |
| void *refcount_block; |
| |
| refcount_table_index = cluster_index >> s->refcount_block_bits; |
| if (refcount_table_index >= s->refcount_table_size) { |
| *refcount = 0; |
| return 0; |
| } |
| refcount_block_offset = |
| s->refcount_table[refcount_table_index] & REFT_OFFSET_MASK; |
| if (!refcount_block_offset) { |
| *refcount = 0; |
| return 0; |
| } |
| |
| if (offset_into_cluster(s, refcount_block_offset)) { |
| qcow2_signal_corruption(bs, true, -1, -1, "Refblock offset %#" PRIx64 |
| " unaligned (reftable index: %#" PRIx64 ")", |
| refcount_block_offset, refcount_table_index); |
| return -EIO; |
| } |
| |
| ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset, |
| &refcount_block); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| block_index = cluster_index & (s->refcount_block_size - 1); |
| *refcount = s->get_refcount(refcount_block, block_index); |
| |
| qcow2_cache_put(bs, s->refcount_block_cache, &refcount_block); |
| |
| return 0; |
| } |
| |
| /* |
| * Rounds the refcount table size up to avoid growing the table for each single |
| * refcount block that is allocated. |
| */ |
| static unsigned int next_refcount_table_size(BDRVQcow2State *s, |
| unsigned int min_size) |
| { |
| unsigned int min_clusters = (min_size >> (s->cluster_bits - 3)) + 1; |
| unsigned int refcount_table_clusters = |
| MAX(1, s->refcount_table_size >> (s->cluster_bits - 3)); |
| |
| while (min_clusters > refcount_table_clusters) { |
| refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; |
| } |
| |
| return refcount_table_clusters << (s->cluster_bits - 3); |
| } |
| |
| |
| /* Checks if two offsets are described by the same refcount block */ |
| static int in_same_refcount_block(BDRVQcow2State *s, uint64_t offset_a, |
| uint64_t offset_b) |
| { |
| uint64_t block_a = offset_a >> (s->cluster_bits + s->refcount_block_bits); |
| uint64_t block_b = offset_b >> (s->cluster_bits + s->refcount_block_bits); |
| |
| return (block_a == block_b); |
| } |
| |
| /* |
| * Loads a refcount block. If it doesn't exist yet, it is allocated first |
| * (including growing the refcount table if needed). |
| * |
| * Returns 0 on success or -errno in error case |
| */ |
| static int alloc_refcount_block(BlockDriverState *bs, |
| int64_t cluster_index, void **refcount_block) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| unsigned int refcount_table_index; |
| int ret; |
| |
| BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); |
| |
| /* Find the refcount block for the given cluster */ |
| refcount_table_index = cluster_index >> s->refcount_block_bits; |
| |
| if (refcount_table_index < s->refcount_table_size) { |
| |
| uint64_t refcount_block_offset = |
| s->refcount_table[refcount_table_index] & REFT_OFFSET_MASK; |
| |
| /* If it's already there, we're done */ |
| if (refcount_block_offset) { |
| if (offset_into_cluster(s, refcount_block_offset)) { |
| qcow2_signal_corruption(bs, true, -1, -1, "Refblock offset %#" |
| PRIx64 " unaligned (reftable index: " |
| "%#x)", refcount_block_offset, |
| refcount_table_index); |
| return -EIO; |
| } |
| |
| return load_refcount_block(bs, refcount_block_offset, |
| refcount_block); |
| } |
| } |
| |
| /* |
| * If we came here, we need to allocate something. Something is at least |
| * a cluster for the new refcount block. It may also include a new refcount |
| * table if the old refcount table is too small. |
| * |
| * Note that allocating clusters here needs some special care: |
| * |
| * - We can't use the normal qcow2_alloc_clusters(), it would try to |
| * increase the refcount and very likely we would end up with an endless |
| * recursion. Instead we must place the refcount blocks in a way that |
| * they can describe them themselves. |
| * |
| * - We need to consider that at this point we are inside update_refcounts |
| * and potentially doing an initial refcount increase. This means that |
| * some clusters have already been allocated by the caller, but their |
| * refcount isn't accurate yet. If we allocate clusters for metadata, we |
| * need to return -EAGAIN to signal the caller that it needs to restart |
| * the search for free clusters. |
| * |
| * - alloc_clusters_noref and qcow2_free_clusters may load a different |
| * refcount block into the cache |
| */ |
| |
| *refcount_block = NULL; |
| |
| /* We write to the refcount table, so we might depend on L2 tables */ |
| ret = qcow2_cache_flush(bs, s->l2_table_cache); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| /* Allocate the refcount block itself and mark it as used */ |
| int64_t new_block = alloc_clusters_noref(bs, s->cluster_size); |
| if (new_block < 0) { |
| return new_block; |
| } |
| |
| #ifdef DEBUG_ALLOC2 |
| fprintf(stderr, "qcow2: Allocate refcount block %d for %" PRIx64 |
| " at %" PRIx64 "\n", |
| refcount_table_index, cluster_index << s->cluster_bits, new_block); |
| #endif |
| |
| if (in_same_refcount_block(s, new_block, cluster_index << s->cluster_bits)) { |
| /* Zero the new refcount block before updating it */ |
| ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, |
| refcount_block); |
| if (ret < 0) { |
| goto fail_block; |
| } |
| |
| memset(*refcount_block, 0, s->cluster_size); |
| |
| /* The block describes itself, need to update the cache */ |
| int block_index = (new_block >> s->cluster_bits) & |
| (s->refcount_block_size - 1); |
| s->set_refcount(*refcount_block, block_index, 1); |
| } else { |
| /* Described somewhere else. This can recurse at most twice before we |
| * arrive at a block that describes itself. */ |
| ret = update_refcount(bs, new_block, s->cluster_size, 1, false, |
| QCOW2_DISCARD_NEVER); |
| if (ret < 0) { |
| goto fail_block; |
| } |
| |
| ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
| if (ret < 0) { |
| goto fail_block; |
| } |
| |
| /* Initialize the new refcount block only after updating its refcount, |
| * update_refcount uses the refcount cache itself */ |
| ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, |
| refcount_block); |
| if (ret < 0) { |
| goto fail_block; |
| } |
| |
| memset(*refcount_block, 0, s->cluster_size); |
| } |
| |
| /* Now the new refcount block needs to be written to disk */ |
| BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE); |
| qcow2_cache_entry_mark_dirty(bs, s->refcount_block_cache, *refcount_block); |
| ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
| if (ret < 0) { |
| goto fail_block; |
| } |
| |
| /* If the refcount table is big enough, just hook the block up there */ |
| if (refcount_table_index < s->refcount_table_size) { |
| uint64_t data64 = cpu_to_be64(new_block); |
| BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_HOOKUP); |
| ret = bdrv_pwrite_sync(bs->file->bs, |
| s->refcount_table_offset + refcount_table_index * sizeof(uint64_t), |
| &data64, sizeof(data64)); |
| if (ret < 0) { |
| goto fail_block; |
| } |
| |
| s->refcount_table[refcount_table_index] = new_block; |
| |
| /* The new refcount block may be where the caller intended to put its |
| * data, so let it restart the search. */ |
| return -EAGAIN; |
| } |
| |
| qcow2_cache_put(bs, s->refcount_block_cache, refcount_block); |
| |
| /* |
| * If we come here, we need to grow the refcount table. Again, a new |
| * refcount table needs some space and we can't simply allocate to avoid |
| * endless recursion. |
| * |
| * Therefore let's grab new refcount blocks at the end of the image, which |
| * will describe themselves and the new refcount table. This way we can |
| * reference them only in the new table and do the switch to the new |
| * refcount table at once without producing an inconsistent state in |
| * between. |
| */ |
| BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_GROW); |
| |
| /* Calculate the number of refcount blocks needed so far; this will be the |
| * basis for calculating the index of the first cluster used for the |
| * self-describing refcount structures which we are about to create. |
| * |
| * Because we reached this point, there cannot be any refcount entries for |
| * cluster_index or higher indices yet. However, because new_block has been |
| * allocated to describe that cluster (and it will assume this role later |
| * on), we cannot use that index; also, new_block may actually have a higher |
| * cluster index than cluster_index, so it needs to be taken into account |
| * here (and 1 needs to be added to its value because that cluster is used). |
| */ |
| uint64_t blocks_used = DIV_ROUND_UP(MAX(cluster_index + 1, |
| (new_block >> s->cluster_bits) + 1), |
| s->refcount_block_size); |
| |
| if (blocks_used > QCOW_MAX_REFTABLE_SIZE / sizeof(uint64_t)) { |
| return -EFBIG; |
| } |
| |
| /* And now we need at least one block more for the new metadata */ |
| uint64_t table_size = next_refcount_table_size(s, blocks_used + 1); |
| uint64_t last_table_size; |
| uint64_t blocks_clusters; |
| do { |
| uint64_t table_clusters = |
| size_to_clusters(s, table_size * sizeof(uint64_t)); |
| blocks_clusters = 1 + |
| ((table_clusters + s->refcount_block_size - 1) |
| / s->refcount_block_size); |
| uint64_t meta_clusters = table_clusters + blocks_clusters; |
| |
| last_table_size = table_size; |
| table_size = next_refcount_table_size(s, blocks_used + |
| ((meta_clusters + s->refcount_block_size - 1) |
| / s->refcount_block_size)); |
| |
| } while (last_table_size != table_size); |
| |
| #ifdef DEBUG_ALLOC2 |
| fprintf(stderr, "qcow2: Grow refcount table %" PRId32 " => %" PRId64 "\n", |
| s->refcount_table_size, table_size); |
| #endif |
| |
| /* Create the new refcount table and blocks */ |
| uint64_t meta_offset = (blocks_used * s->refcount_block_size) * |
| s->cluster_size; |
| uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size; |
| uint64_t *new_table = g_try_new0(uint64_t, table_size); |
| void *new_blocks = g_try_malloc0(blocks_clusters * s->cluster_size); |
| |
| assert(table_size > 0 && blocks_clusters > 0); |
| if (new_table == NULL || new_blocks == NULL) { |
| ret = -ENOMEM; |
| goto fail_table; |
| } |
| |
| /* Fill the new refcount table */ |
| memcpy(new_table, s->refcount_table, |
| s->refcount_table_size * sizeof(uint64_t)); |
| new_table[refcount_table_index] = new_block; |
| |
| int i; |
| for (i = 0; i < blocks_clusters; i++) { |
| new_table[blocks_used + i] = meta_offset + (i * s->cluster_size); |
| } |
| |
| /* Fill the refcount blocks */ |
| uint64_t table_clusters = size_to_clusters(s, table_size * sizeof(uint64_t)); |
| int block = 0; |
| for (i = 0; i < table_clusters + blocks_clusters; i++) { |
| s->set_refcount(new_blocks, block++, 1); |
| } |
| |
| /* Write refcount blocks to disk */ |
| BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS); |
| ret = bdrv_pwrite_sync(bs->file->bs, meta_offset, new_blocks, |
| blocks_clusters * s->cluster_size); |
| g_free(new_blocks); |
| new_blocks = NULL; |
| if (ret < 0) { |
| goto fail_table; |
| } |
| |
| /* Write refcount table to disk */ |
| for(i = 0; i < table_size; i++) { |
| cpu_to_be64s(&new_table[i]); |
| } |
| |
| BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE); |
| ret = bdrv_pwrite_sync(bs->file->bs, table_offset, new_table, |
| table_size * sizeof(uint64_t)); |
| if (ret < 0) { |
| goto fail_table; |
| } |
| |
| for(i = 0; i < table_size; i++) { |
| be64_to_cpus(&new_table[i]); |
| } |
| |
| /* Hook up the new refcount table in the qcow2 header */ |
| struct QEMU_PACKED { |
| uint64_t d64; |
| uint32_t d32; |
| } data; |
| cpu_to_be64w(&data.d64, table_offset); |
| cpu_to_be32w(&data.d32, table_clusters); |
| BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE); |
| ret = bdrv_pwrite_sync(bs->file->bs, |
| offsetof(QCowHeader, refcount_table_offset), |
| &data, sizeof(data)); |
| if (ret < 0) { |
| goto fail_table; |
| } |
| |
| /* And switch it in memory */ |
| uint64_t old_table_offset = s->refcount_table_offset; |
| uint64_t old_table_size = s->refcount_table_size; |
| |
| g_free(s->refcount_table); |
| s->refcount_table = new_table; |
| s->refcount_table_size = table_size; |
| s->refcount_table_offset = table_offset; |
| |
| /* Free old table. */ |
| qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t), |
| QCOW2_DISCARD_OTHER); |
| |
| ret = load_refcount_block(bs, new_block, refcount_block); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| /* If we were trying to do the initial refcount update for some cluster |
| * allocation, we might have used the same clusters to store newly |
| * allocated metadata. Make the caller search some new space. */ |
| return -EAGAIN; |
| |
| fail_table: |
| g_free(new_blocks); |
| g_free(new_table); |
| fail_block: |
| if (*refcount_block != NULL) { |
| qcow2_cache_put(bs, s->refcount_block_cache, refcount_block); |
| } |
| return ret; |
| } |
| |
| void qcow2_process_discards(BlockDriverState *bs, int ret) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| Qcow2DiscardRegion *d, *next; |
| |
| QTAILQ_FOREACH_SAFE(d, &s->discards, next, next) { |
| QTAILQ_REMOVE(&s->discards, d, next); |
| |
| /* Discard is optional, ignore the return value */ |
| if (ret >= 0) { |
| bdrv_discard(bs->file->bs, |
| d->offset >> BDRV_SECTOR_BITS, |
| d->bytes >> BDRV_SECTOR_BITS); |
| } |
| |
| g_free(d); |
| } |
| } |
| |
| static void update_refcount_discard(BlockDriverState *bs, |
| uint64_t offset, uint64_t length) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| Qcow2DiscardRegion *d, *p, *next; |
| |
| QTAILQ_FOREACH(d, &s->discards, next) { |
| uint64_t new_start = MIN(offset, d->offset); |
| uint64_t new_end = MAX(offset + length, d->offset + d->bytes); |
| |
| if (new_end - new_start <= length + d->bytes) { |
| /* There can't be any overlap, areas ending up here have no |
| * references any more and therefore shouldn't get freed another |
| * time. */ |
| assert(d->bytes + length == new_end - new_start); |
| d->offset = new_start; |
| d->bytes = new_end - new_start; |
| goto found; |
| } |
| } |
| |
| d = g_malloc(sizeof(*d)); |
| *d = (Qcow2DiscardRegion) { |
| .bs = bs, |
| .offset = offset, |
| .bytes = length, |
| }; |
| QTAILQ_INSERT_TAIL(&s->discards, d, next); |
| |
| found: |
| /* Merge discard requests if they are adjacent now */ |
| QTAILQ_FOREACH_SAFE(p, &s->discards, next, next) { |
| if (p == d |
| || p->offset > d->offset + d->bytes |
| || d->offset > p->offset + p->bytes) |
| { |
| continue; |
| } |
| |
| /* Still no overlap possible */ |
| assert(p->offset == d->offset + d->bytes |
| || d->offset == p->offset + p->bytes); |
| |
| QTAILQ_REMOVE(&s->discards, p, next); |
| d->offset = MIN(d->offset, p->offset); |
| d->bytes += p->bytes; |
| g_free(p); |
| } |
| } |
| |
| /* XXX: cache several refcount block clusters ? */ |
| /* @addend is the absolute value of the addend; if @decrease is set, @addend |
| * will be subtracted from the current refcount, otherwise it will be added */ |
| static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
| int64_t offset, |
| int64_t length, |
| uint64_t addend, |
| bool decrease, |
| enum qcow2_discard_type type) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int64_t start, last, cluster_offset; |
| void *refcount_block = NULL; |
| int64_t old_table_index = -1; |
| int ret; |
| |
| #ifdef DEBUG_ALLOC2 |
| fprintf(stderr, "update_refcount: offset=%" PRId64 " size=%" PRId64 |
| " addend=%s%" PRIu64 "\n", offset, length, decrease ? "-" : "", |
| addend); |
| #endif |
| if (length < 0) { |
| return -EINVAL; |
| } else if (length == 0) { |
| return 0; |
| } |
| |
| if (decrease) { |
| qcow2_cache_set_dependency(bs, s->refcount_block_cache, |
| s->l2_table_cache); |
| } |
| |
| start = start_of_cluster(s, offset); |
| last = start_of_cluster(s, offset + length - 1); |
| for(cluster_offset = start; cluster_offset <= last; |
| cluster_offset += s->cluster_size) |
| { |
| int block_index; |
| uint64_t refcount; |
| int64_t cluster_index = cluster_offset >> s->cluster_bits; |
| int64_t table_index = cluster_index >> s->refcount_block_bits; |
| |
| /* Load the refcount block and allocate it if needed */ |
| if (table_index != old_table_index) { |
| if (refcount_block) { |
| qcow2_cache_put(bs, s->refcount_block_cache, &refcount_block); |
| } |
| ret = alloc_refcount_block(bs, cluster_index, &refcount_block); |
| if (ret < 0) { |
| goto fail; |
| } |
| } |
| old_table_index = table_index; |
| |
| qcow2_cache_entry_mark_dirty(bs, s->refcount_block_cache, |
| refcount_block); |
| |
| /* we can update the count and save it */ |
| block_index = cluster_index & (s->refcount_block_size - 1); |
| |
| refcount = s->get_refcount(refcount_block, block_index); |
| if (decrease ? (refcount - addend > refcount) |
| : (refcount + addend < refcount || |
| refcount + addend > s->refcount_max)) |
| { |
| ret = -EINVAL; |
| goto fail; |
| } |
| if (decrease) { |
| refcount -= addend; |
| } else { |
| refcount += addend; |
| } |
| if (refcount == 0 && cluster_index < s->free_cluster_index) { |
| s->free_cluster_index = cluster_index; |
| } |
| s->set_refcount(refcount_block, block_index, refcount); |
| |
| if (refcount == 0 && s->discard_passthrough[type]) { |
| update_refcount_discard(bs, cluster_offset, s->cluster_size); |
| } |
| } |
| |
| ret = 0; |
| fail: |
| if (!s->cache_discards) { |
| qcow2_process_discards(bs, ret); |
| } |
| |
| /* Write last changed block to disk */ |
| if (refcount_block) { |
| qcow2_cache_put(bs, s->refcount_block_cache, &refcount_block); |
| } |
| |
| /* |
| * Try do undo any updates if an error is returned (This may succeed in |
| * some cases like ENOSPC for allocating a new refcount block) |
| */ |
| if (ret < 0) { |
| int dummy; |
| dummy = update_refcount(bs, offset, cluster_offset - offset, addend, |
| !decrease, QCOW2_DISCARD_NEVER); |
| (void)dummy; |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * Increases or decreases the refcount of a given cluster. |
| * |
| * @addend is the absolute value of the addend; if @decrease is set, @addend |
| * will be subtracted from the current refcount, otherwise it will be added. |
| * |
| * On success 0 is returned; on failure -errno is returned. |
| */ |
| int qcow2_update_cluster_refcount(BlockDriverState *bs, |
| int64_t cluster_index, |
| uint64_t addend, bool decrease, |
| enum qcow2_discard_type type) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int ret; |
| |
| ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend, |
| decrease, type); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| |
| |
| /*********************************************************/ |
| /* cluster allocation functions */ |
| |
| |
| |
| /* return < 0 if error */ |
| static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| uint64_t i, nb_clusters, refcount; |
| int ret; |
| |
| /* We can't allocate clusters if they may still be queued for discard. */ |
| if (s->cache_discards) { |
| qcow2_process_discards(bs, 0); |
| } |
| |
| nb_clusters = size_to_clusters(s, size); |
| retry: |
| for(i = 0; i < nb_clusters; i++) { |
| uint64_t next_cluster_index = s->free_cluster_index++; |
| ret = qcow2_get_refcount(bs, next_cluster_index, &refcount); |
| |
| if (ret < 0) { |
| return ret; |
| } else if (refcount != 0) { |
| goto retry; |
| } |
| } |
| |
| /* Make sure that all offsets in the "allocated" range are representable |
| * in an int64_t */ |
| if (s->free_cluster_index > 0 && |
| s->free_cluster_index - 1 > (INT64_MAX >> s->cluster_bits)) |
| { |
| return -EFBIG; |
| } |
| |
| #ifdef DEBUG_ALLOC2 |
| fprintf(stderr, "alloc_clusters: size=%" PRId64 " -> %" PRId64 "\n", |
| size, |
| (s->free_cluster_index - nb_clusters) << s->cluster_bits); |
| #endif |
| return (s->free_cluster_index - nb_clusters) << s->cluster_bits; |
| } |
| |
| int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size) |
| { |
| int64_t offset; |
| int ret; |
| |
| BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); |
| do { |
| offset = alloc_clusters_noref(bs, size); |
| if (offset < 0) { |
| return offset; |
| } |
| |
| ret = update_refcount(bs, offset, size, 1, false, QCOW2_DISCARD_NEVER); |
| } while (ret == -EAGAIN); |
| |
| if (ret < 0) { |
| return ret; |
| } |
| |
| return offset; |
| } |
| |
| int64_t qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, |
| int64_t nb_clusters) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| uint64_t cluster_index, refcount; |
| uint64_t i; |
| int ret; |
| |
| assert(nb_clusters >= 0); |
| if (nb_clusters == 0) { |
| return 0; |
| } |
| |
| do { |
| /* Check how many clusters there are free */ |
| cluster_index = offset >> s->cluster_bits; |
| for(i = 0; i < nb_clusters; i++) { |
| ret = qcow2_get_refcount(bs, cluster_index++, &refcount); |
| if (ret < 0) { |
| return ret; |
| } else if (refcount != 0) { |
| break; |
| } |
| } |
| |
| /* And then allocate them */ |
| ret = update_refcount(bs, offset, i << s->cluster_bits, 1, false, |
| QCOW2_DISCARD_NEVER); |
| } while (ret == -EAGAIN); |
| |
| if (ret < 0) { |
| return ret; |
| } |
| |
| return i; |
| } |
| |
| /* only used to allocate compressed sectors. We try to allocate |
| contiguous sectors. size must be <= cluster_size */ |
| int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int64_t offset; |
| size_t free_in_cluster; |
| int ret; |
| |
| BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES); |
| assert(size > 0 && size <= s->cluster_size); |
| assert(!s->free_byte_offset || offset_into_cluster(s, s->free_byte_offset)); |
| |
| offset = s->free_byte_offset; |
| |
| if (offset) { |
| uint64_t refcount; |
| ret = qcow2_get_refcount(bs, offset >> s->cluster_bits, &refcount); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| if (refcount == s->refcount_max) { |
| offset = 0; |
| } |
| } |
| |
| free_in_cluster = s->cluster_size - offset_into_cluster(s, offset); |
| do { |
| if (!offset || free_in_cluster < size) { |
| int64_t new_cluster = alloc_clusters_noref(bs, s->cluster_size); |
| if (new_cluster < 0) { |
| return new_cluster; |
| } |
| |
| if (!offset || ROUND_UP(offset, s->cluster_size) != new_cluster) { |
| offset = new_cluster; |
| free_in_cluster = s->cluster_size; |
| } else { |
| free_in_cluster += s->cluster_size; |
| } |
| } |
| |
| assert(offset); |
| ret = update_refcount(bs, offset, size, 1, false, QCOW2_DISCARD_NEVER); |
| if (ret < 0) { |
| offset = 0; |
| } |
| } while (ret == -EAGAIN); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| /* The cluster refcount was incremented; refcount blocks must be flushed |
| * before the caller's L2 table updates. */ |
| qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache); |
| |
| s->free_byte_offset = offset + size; |
| if (!offset_into_cluster(s, s->free_byte_offset)) { |
| s->free_byte_offset = 0; |
| } |
| |
| return offset; |
| } |
| |
| void qcow2_free_clusters(BlockDriverState *bs, |
| int64_t offset, int64_t size, |
| enum qcow2_discard_type type) |
| { |
| int ret; |
| |
| BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_FREE); |
| ret = update_refcount(bs, offset, size, 1, true, type); |
| if (ret < 0) { |
| fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret)); |
| /* TODO Remember the clusters to free them later and avoid leaking */ |
| } |
| } |
| |
| /* |
| * Free a cluster using its L2 entry (handles clusters of all types, e.g. |
| * normal cluster, compressed cluster, etc.) |
| */ |
| void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry, |
| int nb_clusters, enum qcow2_discard_type type) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| |
| switch (qcow2_get_cluster_type(l2_entry)) { |
| case QCOW2_CLUSTER_COMPRESSED: |
| { |
| int nb_csectors; |
| nb_csectors = ((l2_entry >> s->csize_shift) & |
| s->csize_mask) + 1; |
| qcow2_free_clusters(bs, |
| (l2_entry & s->cluster_offset_mask) & ~511, |
| nb_csectors * 512, type); |
| } |
| break; |
| case QCOW2_CLUSTER_NORMAL: |
| case QCOW2_CLUSTER_ZERO: |
| if (l2_entry & L2E_OFFSET_MASK) { |
| if (offset_into_cluster(s, l2_entry & L2E_OFFSET_MASK)) { |
| qcow2_signal_corruption(bs, false, -1, -1, |
| "Cannot free unaligned cluster %#llx", |
| l2_entry & L2E_OFFSET_MASK); |
| } else { |
| qcow2_free_clusters(bs, l2_entry & L2E_OFFSET_MASK, |
| nb_clusters << s->cluster_bits, type); |
| } |
| } |
| break; |
| case QCOW2_CLUSTER_UNALLOCATED: |
| break; |
| default: |
| abort(); |
| } |
| } |
| |
| |
| |
| /*********************************************************/ |
| /* snapshots and image creation */ |
| |
| |
| |
| /* update the refcounts of snapshots and the copied flag */ |
| int qcow2_update_snapshot_refcount(BlockDriverState *bs, |
| int64_t l1_table_offset, int l1_size, int addend) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, refcount; |
| bool l1_allocated = false; |
| int64_t old_offset, old_l2_offset; |
| int i, j, l1_modified = 0, nb_csectors; |
| int ret; |
| |
| assert(addend >= -1 && addend <= 1); |
| |
| l2_table = NULL; |
| l1_table = NULL; |
| l1_size2 = l1_size * sizeof(uint64_t); |
| |
| s->cache_discards = true; |
| |
| /* WARNING: qcow2_snapshot_goto relies on this function not using the |
| * l1_table_offset when it is the current s->l1_table_offset! Be careful |
| * when changing this! */ |
| if (l1_table_offset != s->l1_table_offset) { |
| l1_table = g_try_malloc0(align_offset(l1_size2, 512)); |
| if (l1_size2 && l1_table == NULL) { |
| ret = -ENOMEM; |
| goto fail; |
| } |
| l1_allocated = true; |
| |
| ret = bdrv_pread(bs->file->bs, l1_table_offset, l1_table, l1_size2); |
| if (ret < 0) { |
| 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 = false; |
| } |
| |
| for(i = 0; i < l1_size; i++) { |
| l2_offset = l1_table[i]; |
| if (l2_offset) { |
| old_l2_offset = l2_offset; |
| l2_offset &= L1E_OFFSET_MASK; |
| |
| 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; |
| } |
| |
| ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, |
| (void**) &l2_table); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| for(j = 0; j < s->l2_size; j++) { |
| uint64_t cluster_index; |
| |
| offset = be64_to_cpu(l2_table[j]); |
| old_offset = offset; |
| offset &= ~QCOW_OFLAG_COPIED; |
| |
| switch (qcow2_get_cluster_type(offset)) { |
| case QCOW2_CLUSTER_COMPRESSED: |
| nb_csectors = ((offset >> s->csize_shift) & |
| s->csize_mask) + 1; |
| if (addend != 0) { |
| ret = update_refcount(bs, |
| (offset & s->cluster_offset_mask) & ~511, |
| nb_csectors * 512, abs(addend), addend < 0, |
| QCOW2_DISCARD_SNAPSHOT); |
| if (ret < 0) { |
| goto fail; |
| } |
| } |
| /* compressed clusters are never modified */ |
| refcount = 2; |
| break; |
| |
| case QCOW2_CLUSTER_NORMAL: |
| case QCOW2_CLUSTER_ZERO: |
| if (offset_into_cluster(s, offset & L2E_OFFSET_MASK)) { |
| qcow2_signal_corruption(bs, true, -1, -1, "Data " |
| "cluster offset %#llx " |
| "unaligned (L2 offset: %#" |
| PRIx64 ", L2 index: %#x)", |
| offset & L2E_OFFSET_MASK, |
| l2_offset, j); |
| ret = -EIO; |
| goto fail; |
| } |
| |
| cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits; |
| if (!cluster_index) { |
| /* unallocated */ |
| refcount = 0; |
| break; |
| } |
| if (addend != 0) { |
| ret = qcow2_update_cluster_refcount(bs, |
| cluster_index, abs(addend), addend < 0, |
| QCOW2_DISCARD_SNAPSHOT); |
| if (ret < 0) { |
| goto fail; |
| } |
| } |
| |
| ret = qcow2_get_refcount(bs, cluster_index, &refcount); |
| if (ret < 0) { |
| goto fail; |
| } |
| break; |
| |
| case QCOW2_CLUSTER_UNALLOCATED: |
| refcount = 0; |
| break; |
| |
| default: |
| abort(); |
| } |
| |
| if (refcount == 1) { |
| offset |= QCOW_OFLAG_COPIED; |
| } |
| if (offset != old_offset) { |
| if (addend > 0) { |
| qcow2_cache_set_dependency(bs, s->l2_table_cache, |
| s->refcount_block_cache); |
| } |
| l2_table[j] = cpu_to_be64(offset); |
| qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, |
| l2_table); |
| } |
| } |
| |
| qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table); |
| |
| if (addend != 0) { |
| ret = qcow2_update_cluster_refcount(bs, l2_offset >> |
| s->cluster_bits, |
| abs(addend), addend < 0, |
| QCOW2_DISCARD_SNAPSHOT); |
| if (ret < 0) { |
| goto fail; |
| } |
| } |
| ret = qcow2_get_refcount(bs, l2_offset >> s->cluster_bits, |
| &refcount); |
| if (ret < 0) { |
| goto fail; |
| } else if (refcount == 1) { |
| l2_offset |= QCOW_OFLAG_COPIED; |
| } |
| if (l2_offset != old_l2_offset) { |
| l1_table[i] = l2_offset; |
| l1_modified = 1; |
| } |
| } |
| } |
| |
| ret = bdrv_flush(bs); |
| fail: |
| if (l2_table) { |
| qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); |
| } |
| |
| s->cache_discards = false; |
| qcow2_process_discards(bs, ret); |
| |
| /* Update L1 only if it isn't deleted anyway (addend = -1) */ |
| if (ret == 0 && addend >= 0 && l1_modified) { |
| for (i = 0; i < l1_size; i++) { |
| cpu_to_be64s(&l1_table[i]); |
| } |
| |
| ret = bdrv_pwrite_sync(bs->file->bs, l1_table_offset, |
| l1_table, l1_size2); |
| |
| for (i = 0; i < l1_size; i++) { |
| be64_to_cpus(&l1_table[i]); |
| } |
| } |
| if (l1_allocated) |
| g_free(l1_table); |
| return ret; |
| } |
| |
| |
| |
| |
| /*********************************************************/ |
| /* refcount checking functions */ |
| |
| |
| static uint64_t refcount_array_byte_size(BDRVQcow2State *s, uint64_t entries) |
| { |
| /* This assertion holds because there is no way we can address more than |
| * 2^(64 - 9) clusters at once (with cluster size 512 = 2^9, and because |
| * offsets have to be representable in bytes); due to every cluster |
| * corresponding to one refcount entry, we are well below that limit */ |
| assert(entries < (UINT64_C(1) << (64 - 9))); |
| |
| /* Thanks to the assertion this will not overflow, because |
| * s->refcount_order < 7. |
| * (note: x << s->refcount_order == x * s->refcount_bits) */ |
| return DIV_ROUND_UP(entries << s->refcount_order, 8); |
| } |
| |
| /** |
| * Reallocates *array so that it can hold new_size entries. *size must contain |
| * the current number of entries in *array. If the reallocation fails, *array |
| * and *size will not be modified and -errno will be returned. If the |
| * reallocation is successful, *array will be set to the new buffer, *size |
| * will be set to new_size and 0 will be returned. The size of the reallocated |
| * refcount array buffer will be aligned to a cluster boundary, and the newly |
| * allocated area will be zeroed. |
| */ |
| static int realloc_refcount_array(BDRVQcow2State *s, void **array, |
| int64_t *size, int64_t new_size) |
| { |
| int64_t old_byte_size, new_byte_size; |
| void *new_ptr; |
| |
| /* Round to clusters so the array can be directly written to disk */ |
| old_byte_size = size_to_clusters(s, refcount_array_byte_size(s, *size)) |
| * s->cluster_size; |
| new_byte_size = size_to_clusters(s, refcount_array_byte_size(s, new_size)) |
| * s->cluster_size; |
| |
| if (new_byte_size == old_byte_size) { |
| *size = new_size; |
| return 0; |
| } |
| |
| assert(new_byte_size > 0); |
| |
| if (new_byte_size > SIZE_MAX) { |
| return -ENOMEM; |
| } |
| |
| new_ptr = g_try_realloc(*array, new_byte_size); |
| if (!new_ptr) { |
| return -ENOMEM; |
| } |
| |
| if (new_byte_size > old_byte_size) { |
| memset((char *)new_ptr + old_byte_size, 0, |
| new_byte_size - old_byte_size); |
| } |
| |
| *array = new_ptr; |
| *size = new_size; |
| |
| return 0; |
| } |
| |
| /* |
| * Increases the refcount for a range of clusters in a given refcount table. |
| * This is used to construct a temporary refcount table out of L1 and L2 tables |
| * which can be compared to the refcount table saved in the image. |
| * |
| * Modifies the number of errors in res. |
| */ |
| static int inc_refcounts(BlockDriverState *bs, |
| BdrvCheckResult *res, |
| void **refcount_table, |
| int64_t *refcount_table_size, |
| int64_t offset, int64_t size) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| uint64_t start, last, cluster_offset, k, refcount; |
| int ret; |
| |
| if (size <= 0) { |
| return 0; |
| } |
| |
| start = start_of_cluster(s, offset); |
| last = start_of_cluster(s, offset + size - 1); |
| for(cluster_offset = start; cluster_offset <= last; |
| cluster_offset += s->cluster_size) { |
| k = cluster_offset >> s->cluster_bits; |
| if (k >= *refcount_table_size) { |
| ret = realloc_refcount_array(s, refcount_table, |
| refcount_table_size, k + 1); |
| if (ret < 0) { |
| res->check_errors++; |
| return ret; |
| } |
| } |
| |
| refcount = s->get_refcount(*refcount_table, k); |
| if (refcount == s->refcount_max) { |
| fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64 |
| "\n", cluster_offset); |
| fprintf(stderr, "Use qemu-img amend to increase the refcount entry " |
| "width or qemu-img convert to create a clean copy if the " |
| "image cannot be opened for writing\n"); |
| res->corruptions++; |
| continue; |
| } |
| s->set_refcount(*refcount_table, k, refcount + 1); |
| } |
| |
| return 0; |
| } |
| |
| /* Flags for check_refcounts_l1() and check_refcounts_l2() */ |
| enum { |
| CHECK_FRAG_INFO = 0x2, /* update BlockFragInfo counters */ |
| }; |
| |
| /* |
| * Increases the refcount in the given refcount table for the all clusters |
| * referenced in the L2 table. While doing so, performs some checks on L2 |
| * entries. |
| * |
| * Returns the number of errors found by the checks or -errno if an internal |
| * error occurred. |
| */ |
| static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res, |
| void **refcount_table, |
| int64_t *refcount_table_size, int64_t l2_offset, |
| int flags) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| uint64_t *l2_table, l2_entry; |
| uint64_t next_contiguous_offset = 0; |
| int i, l2_size, nb_csectors, ret; |
| |
| /* Read L2 table from disk */ |
| l2_size = s->l2_size * sizeof(uint64_t); |
| l2_table = g_malloc(l2_size); |
| |
| ret = bdrv_pread(bs->file->bs, l2_offset, l2_table, l2_size); |
| if (ret < 0) { |
| fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n"); |
| res->check_errors++; |
| goto fail; |
| } |
| |
| /* Do the actual checks */ |
| for(i = 0; i < s->l2_size; i++) { |
| l2_entry = be64_to_cpu(l2_table[i]); |
| |
| switch (qcow2_get_cluster_type(l2_entry)) { |
| case QCOW2_CLUSTER_COMPRESSED: |
| /* Compressed clusters don't have QCOW_OFLAG_COPIED */ |
| if (l2_entry & QCOW_OFLAG_COPIED) { |
| fprintf(stderr, "ERROR: cluster %" PRId64 ": " |
| "copied flag must never be set for compressed " |
| "clusters\n", l2_entry >> s->cluster_bits); |
| l2_entry &= ~QCOW_OFLAG_COPIED; |
| res->corruptions++; |
| } |
| |
| /* Mark cluster as used */ |
| nb_csectors = ((l2_entry >> s->csize_shift) & |
| s->csize_mask) + 1; |
| l2_entry &= s->cluster_offset_mask; |
| ret = inc_refcounts(bs, res, refcount_table, refcount_table_size, |
| l2_entry & ~511, nb_csectors * 512); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| if (flags & CHECK_FRAG_INFO) { |
| res->bfi.allocated_clusters++; |
| res->bfi.compressed_clusters++; |
| |
| /* Compressed clusters are fragmented by nature. Since they |
| * take up sub-sector space but we only have sector granularity |
| * I/O we need to re-read the same sectors even for adjacent |
| * compressed clusters. |
| */ |
| res->bfi.fragmented_clusters++; |
| } |
| break; |
| |
| case QCOW2_CLUSTER_ZERO: |
| if ((l2_entry & L2E_OFFSET_MASK) == 0) { |
| break; |
| } |
| /* fall through */ |
| |
| case QCOW2_CLUSTER_NORMAL: |
| { |
| uint64_t offset = l2_entry & L2E_OFFSET_MASK; |
| |
| if (flags & CHECK_FRAG_INFO) { |
| res->bfi.allocated_clusters++; |
| if (next_contiguous_offset && |
| offset != next_contiguous_offset) { |
| res->bfi.fragmented_clusters++; |
| } |
| next_contiguous_offset = offset + s->cluster_size; |
| } |
| |
| /* Mark cluster as used */ |
| ret = inc_refcounts(bs, res, refcount_table, refcount_table_size, |
| offset, s->cluster_size); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| /* Correct offsets are cluster aligned */ |
| if (offset_into_cluster(s, offset)) { |
| fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " |
| "properly aligned; L2 entry corrupted.\n", offset); |
| res->corruptions++; |
| } |
| break; |
| } |
| |
| case QCOW2_CLUSTER_UNALLOCATED: |
| break; |
| |
| default: |
| abort(); |
| } |
| } |
| |
| g_free(l2_table); |
| return 0; |
| |
| fail: |
| g_free(l2_table); |
| return ret; |
| } |
| |
| /* |
| * Increases the refcount for the L1 table, its L2 tables and all referenced |
| * clusters in the given refcount table. While doing so, performs some checks |
| * on L1 and L2 entries. |
| * |
| * Returns the number of errors found by the checks or -errno if an internal |
| * error occurred. |
| */ |
| static int check_refcounts_l1(BlockDriverState *bs, |
| BdrvCheckResult *res, |
| void **refcount_table, |
| int64_t *refcount_table_size, |
| int64_t l1_table_offset, int l1_size, |
| int flags) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| uint64_t *l1_table = NULL, l2_offset, l1_size2; |
| int i, ret; |
| |
| l1_size2 = l1_size * sizeof(uint64_t); |
| |
| /* Mark L1 table as used */ |
| ret = inc_refcounts(bs, res, refcount_table, refcount_table_size, |
| l1_table_offset, l1_size2); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| /* Read L1 table entries from disk */ |
| if (l1_size2 > 0) { |
| l1_table = g_try_malloc(l1_size2); |
| if (l1_table == NULL) { |
| ret = -ENOMEM; |
| res->check_errors++; |
| goto fail; |
| } |
| ret = bdrv_pread(bs->file->bs, l1_table_offset, l1_table, l1_size2); |
| if (ret < 0) { |
| fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); |
| res->check_errors++; |
| goto fail; |
| } |
| for(i = 0;i < l1_size; i++) |
| be64_to_cpus(&l1_table[i]); |
| } |
| |
| /* Do the actual checks */ |
| for(i = 0; i < l1_size; i++) { |
| l2_offset = l1_table[i]; |
| if (l2_offset) { |
| /* Mark L2 table as used */ |
| l2_offset &= L1E_OFFSET_MASK; |
| ret = inc_refcounts(bs, res, refcount_table, refcount_table_size, |
| l2_offset, s->cluster_size); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| /* L2 tables are cluster aligned */ |
| if (offset_into_cluster(s, l2_offset)) { |
| fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " |
| "cluster aligned; L1 entry corrupted\n", l2_offset); |
| res->corruptions++; |
| } |
| |
| /* Process and check L2 entries */ |
| ret = check_refcounts_l2(bs, res, refcount_table, |
| refcount_table_size, l2_offset, flags); |
| if (ret < 0) { |
| goto fail; |
| } |
| } |
| } |
| g_free(l1_table); |
| return 0; |
| |
| fail: |
| g_free(l1_table); |
| return ret; |
| } |
| |
| /* |
| * Checks the OFLAG_COPIED flag for all L1 and L2 entries. |
| * |
| * This function does not print an error message nor does it increment |
| * check_errors if qcow2_get_refcount fails (this is because such an error will |
| * have been already detected and sufficiently signaled by the calling function |
| * (qcow2_check_refcounts) by the time this function is called). |
| */ |
| static int check_oflag_copied(BlockDriverState *bs, BdrvCheckResult *res, |
| BdrvCheckMode fix) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| uint64_t *l2_table = qemu_blockalign(bs, s->cluster_size); |
| int ret; |
| uint64_t refcount; |
| int i, j; |
| |
| for (i = 0; i < s->l1_size; i++) { |
| uint64_t l1_entry = s->l1_table[i]; |
| uint64_t l2_offset = l1_entry & L1E_OFFSET_MASK; |
| bool l2_dirty = false; |
| |
| if (!l2_offset) { |
| continue; |
| } |
| |
| ret = qcow2_get_refcount(bs, l2_offset >> s->cluster_bits, |
| &refcount); |
| if (ret < 0) { |
| /* don't print message nor increment check_errors */ |
| continue; |
| } |
| if ((refcount == 1) != ((l1_entry & QCOW_OFLAG_COPIED) != 0)) { |
| fprintf(stderr, "%s OFLAG_COPIED L2 cluster: l1_index=%d " |
| "l1_entry=%" PRIx64 " refcount=%" PRIu64 "\n", |
| fix & BDRV_FIX_ERRORS ? "Repairing" : |
| "ERROR", |
| i, l1_entry, refcount); |
| if (fix & BDRV_FIX_ERRORS) { |
| s->l1_table[i] = refcount == 1 |
| ? l1_entry | QCOW_OFLAG_COPIED |
| : l1_entry & ~QCOW_OFLAG_COPIED; |
| ret = qcow2_write_l1_entry(bs, i); |
| if (ret < 0) { |
| res->check_errors++; |
| goto fail; |
| } |
| res->corruptions_fixed++; |
| } else { |
| res->corruptions++; |
| } |
| } |
| |
| ret = bdrv_pread(bs->file->bs, l2_offset, l2_table, |
| s->l2_size * sizeof(uint64_t)); |
| if (ret < 0) { |
| fprintf(stderr, "ERROR: Could not read L2 table: %s\n", |
| strerror(-ret)); |
| res->check_errors++; |
| goto fail; |
| } |
| |
| for (j = 0; j < s->l2_size; j++) { |
| uint64_t l2_entry = be64_to_cpu(l2_table[j]); |
| uint64_t data_offset = l2_entry & L2E_OFFSET_MASK; |
| int cluster_type = qcow2_get_cluster_type(l2_entry); |
| |
| if ((cluster_type == QCOW2_CLUSTER_NORMAL) || |
| ((cluster_type == QCOW2_CLUSTER_ZERO) && (data_offset != 0))) { |
| ret = qcow2_get_refcount(bs, |
| data_offset >> s->cluster_bits, |
| &refcount); |
| if (ret < 0) { |
| /* don't print message nor increment check_errors */ |
| continue; |
| } |
| if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) { |
| fprintf(stderr, "%s OFLAG_COPIED data cluster: " |
| "l2_entry=%" PRIx64 " refcount=%" PRIu64 "\n", |
| fix & BDRV_FIX_ERRORS ? "Repairing" : |
| "ERROR", |
| l2_entry, refcount); |
| if (fix & BDRV_FIX_ERRORS) { |
| l2_table[j] = cpu_to_be64(refcount == 1 |
| ? l2_entry | QCOW_OFLAG_COPIED |
| : l2_entry & ~QCOW_OFLAG_COPIED); |
| l2_dirty = true; |
| res->corruptions_fixed++; |
| } else { |
| res->corruptions++; |
| } |
| } |
| } |
| } |
| |
| if (l2_dirty) { |
| ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L2, |
| l2_offset, s->cluster_size); |
| if (ret < 0) { |
| fprintf(stderr, "ERROR: Could not write L2 table; metadata " |
| "overlap check failed: %s\n", strerror(-ret)); |
| res->check_errors++; |
| goto fail; |
| } |
| |
| ret = bdrv_pwrite(bs->file->bs, l2_offset, l2_table, |
| s->cluster_size); |
| if (ret < 0) { |
| fprintf(stderr, "ERROR: Could not write L2 table: %s\n", |
| strerror(-ret)); |
| res->check_errors++; |
| goto fail; |
| } |
| } |
| } |
| |
| ret = 0; |
| |
| fail: |
| qemu_vfree(l2_table); |
| return ret; |
| } |
| |
| /* |
| * Checks consistency of refblocks and accounts for each refblock in |
| * *refcount_table. |
| */ |
| static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res, |
| BdrvCheckMode fix, bool *rebuild, |
| void **refcount_table, int64_t *nb_clusters) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int64_t i, size; |
| int ret; |
| |
| for(i = 0; i < s->refcount_table_size; i++) { |
| uint64_t offset, cluster; |
| offset = s->refcount_table[i]; |
| cluster = offset >> s->cluster_bits; |
| |
| /* Refcount blocks are cluster aligned */ |
| if (offset_into_cluster(s, offset)) { |
| fprintf(stderr, "ERROR refcount block %" PRId64 " is not " |
| "cluster aligned; refcount table entry corrupted\n", i); |
| res->corruptions++; |
| *rebuild = true; |
| continue; |
| } |
| |
| if (cluster >= *nb_clusters) { |
| fprintf(stderr, "%s refcount block %" PRId64 " is outside image\n", |
| fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i); |
| |
| if (fix & BDRV_FIX_ERRORS) { |
| int64_t new_nb_clusters; |
| |
| if (offset > INT64_MAX - s->cluster_size) { |
| ret = -EINVAL; |
| goto resize_fail; |
| } |
| |
| ret = bdrv_truncate(bs->file->bs, offset + s->cluster_size); |
| if (ret < 0) { |
| goto resize_fail; |
| } |
| size = bdrv_getlength(bs->file->bs); |
| if (size < 0) { |
| ret = size; |
| goto resize_fail; |
| } |
| |
| new_nb_clusters = size_to_clusters(s, size); |
| assert(new_nb_clusters >= *nb_clusters); |
| |
| ret = realloc_refcount_array(s, refcount_table, |
| nb_clusters, new_nb_clusters); |
| if (ret < 0) { |
| res->check_errors++; |
| return ret; |
| } |
| |
| if (cluster >= *nb_clusters) { |
| ret = -EINVAL; |
| goto resize_fail; |
| } |
| |
| res->corruptions_fixed++; |
| ret = inc_refcounts(bs, res, refcount_table, nb_clusters, |
| offset, s->cluster_size); |
| if (ret < 0) { |
| return ret; |
| } |
| /* No need to check whether the refcount is now greater than 1: |
| * This area was just allocated and zeroed, so it can only be |
| * exactly 1 after inc_refcounts() */ |
| continue; |
| |
| resize_fail: |
| res->corruptions++; |
| *rebuild = true; |
| fprintf(stderr, "ERROR could not resize image: %s\n", |
| strerror(-ret)); |
| } else { |
| res->corruptions++; |
| } |
| continue; |
| } |
| |
| if (offset != 0) { |
| ret = inc_refcounts(bs, res, refcount_table, nb_clusters, |
| offset, s->cluster_size); |
| if (ret < 0) { |
| return ret; |
| } |
| if (s->get_refcount(*refcount_table, cluster) != 1) { |
| fprintf(stderr, "ERROR refcount block %" PRId64 |
| " refcount=%" PRIu64 "\n", i, |
| s->get_refcount(*refcount_table, cluster)); |
| res->corruptions++; |
| *rebuild = true; |
| } |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Calculates an in-memory refcount table. |
| */ |
| static int calculate_refcounts(BlockDriverState *bs, BdrvCheckResult *res, |
| BdrvCheckMode fix, bool *rebuild, |
| void **refcount_table, int64_t *nb_clusters) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int64_t i; |
| QCowSnapshot *sn; |
| int ret; |
| |
| if (!*refcount_table) { |
| int64_t old_size = 0; |
| ret = realloc_refcount_array(s, refcount_table, |
| &old_size, *nb_clusters); |
| if (ret < 0) { |
| res->check_errors++; |
| return ret; |
| } |
| } |
| |
| /* header */ |
| ret = inc_refcounts(bs, res, refcount_table, nb_clusters, |
| 0, s->cluster_size); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| /* current L1 table */ |
| ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
| s->l1_table_offset, s->l1_size, CHECK_FRAG_INFO); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| /* snapshots */ |
| for (i = 0; i < s->nb_snapshots; i++) { |
| sn = s->snapshots + i; |
| ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
| sn->l1_table_offset, sn->l1_size, 0); |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| ret = inc_refcounts(bs, res, refcount_table, nb_clusters, |
| s->snapshots_offset, s->snapshots_size); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| /* refcount data */ |
| ret = inc_refcounts(bs, res, refcount_table, nb_clusters, |
| s->refcount_table_offset, |
| s->refcount_table_size * sizeof(uint64_t)); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| return check_refblocks(bs, res, fix, rebuild, refcount_table, nb_clusters); |
| } |
| |
| /* |
| * Compares the actual reference count for each cluster in the image against the |
| * refcount as reported by the refcount structures on-disk. |
| */ |
| static void compare_refcounts(BlockDriverState *bs, BdrvCheckResult *res, |
| BdrvCheckMode fix, bool *rebuild, |
| int64_t *highest_cluster, |
| void *refcount_table, int64_t nb_clusters) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int64_t i; |
| uint64_t refcount1, refcount2; |
| int ret; |
| |
| for (i = 0, *highest_cluster = 0; i < nb_clusters; i++) { |
| ret = qcow2_get_refcount(bs, i, &refcount1); |
| if (ret < 0) { |
| fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n", |
| i, strerror(-ret)); |
| res->check_errors++; |
| continue; |
| } |
| |
| refcount2 = s->get_refcount(refcount_table, i); |
| |
| if (refcount1 > 0 || refcount2 > 0) { |
| *highest_cluster = i; |
| } |
| |
| if (refcount1 != refcount2) { |
| /* Check if we're allowed to fix the mismatch */ |
| int *num_fixed = NULL; |
| if (refcount1 == 0) { |
| *rebuild = true; |
| } else if (refcount1 > refcount2 && (fix & BDRV_FIX_LEAKS)) { |
| num_fixed = &res->leaks_fixed; |
| } else if (refcount1 < refcount2 && (fix & BDRV_FIX_ERRORS)) { |
| num_fixed = &res->corruptions_fixed; |
| } |
| |
| fprintf(stderr, "%s cluster %" PRId64 " refcount=%" PRIu64 |
| " reference=%" PRIu64 "\n", |
| num_fixed != NULL ? "Repairing" : |
| refcount1 < refcount2 ? "ERROR" : |
| "Leaked", |
| i, refcount1, refcount2); |
| |
| if (num_fixed) { |
| ret = update_refcount(bs, i << s->cluster_bits, 1, |
| refcount_diff(refcount1, refcount2), |
| refcount1 > refcount2, |
| QCOW2_DISCARD_ALWAYS); |
| if (ret >= 0) { |
| (*num_fixed)++; |
| continue; |
| } |
| } |
| |
| /* And if we couldn't, print an error */ |
| if (refcount1 < refcount2) { |
| res->corruptions++; |
| } else { |
| res->leaks++; |
| } |
| } |
| } |
| } |
| |
| /* |
| * Allocates clusters using an in-memory refcount table (IMRT) in contrast to |
| * the on-disk refcount structures. |
| * |
| * On input, *first_free_cluster tells where to start looking, and need not |
| * actually be a free cluster; the returned offset will not be before that |
| * cluster. On output, *first_free_cluster points to the first gap found, even |
| * if that gap was too small to be used as the returned offset. |
| * |
| * Note that *first_free_cluster is a cluster index whereas the return value is |
| * an offset. |
| */ |
| static int64_t alloc_clusters_imrt(BlockDriverState *bs, |
| int cluster_count, |
| void **refcount_table, |
| int64_t *imrt_nb_clusters, |
| int64_t *first_free_cluster) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int64_t cluster = *first_free_cluster, i; |
| bool first_gap = true; |
| int contiguous_free_clusters; |
| int ret; |
| |
| /* Starting at *first_free_cluster, find a range of at least cluster_count |
| * continuously free clusters */ |
| for (contiguous_free_clusters = 0; |
| cluster < *imrt_nb_clusters && |
| contiguous_free_clusters < cluster_count; |
| cluster++) |
| { |
| if (!s->get_refcount(*refcount_table, cluster)) { |
| contiguous_free_clusters++; |
| if (first_gap) { |
| /* If this is the first free cluster found, update |
| * *first_free_cluster accordingly */ |
| *first_free_cluster = cluster; |
| first_gap = false; |
| } |
| } else if (contiguous_free_clusters) { |
| contiguous_free_clusters = 0; |
| } |
| } |
| |
| /* If contiguous_free_clusters is greater than zero, it contains the number |
| * of continuously free clusters until the current cluster; the first free |
| * cluster in the current "gap" is therefore |
| * cluster - contiguous_free_clusters */ |
| |
| /* If no such range could be found, grow the in-memory refcount table |
| * accordingly to append free clusters at the end of the image */ |
| if (contiguous_free_clusters < cluster_count) { |
| /* contiguous_free_clusters clusters are already empty at the image end; |
| * we need cluster_count clusters; therefore, we have to allocate |
| * cluster_count - contiguous_free_clusters new clusters at the end of |
| * the image (which is the current value of cluster; note that cluster |
| * may exceed old_imrt_nb_clusters if *first_free_cluster pointed beyond |
| * the image end) */ |
| ret = realloc_refcount_array(s, refcount_table, imrt_nb_clusters, |
| cluster + cluster_count |
| - contiguous_free_clusters); |
| if (ret < 0) { |
| return ret; |
| } |
| } |
| |
| /* Go back to the first free cluster */ |
| cluster -= contiguous_free_clusters; |
| for (i = 0; i < cluster_count; i++) { |
| s->set_refcount(*refcount_table, cluster + i, 1); |
| } |
| |
| return cluster << s->cluster_bits; |
| } |
| |
| /* |
| * Creates a new refcount structure based solely on the in-memory information |
| * given through *refcount_table. All necessary allocations will be reflected |
| * in that array. |
| * |
| * On success, the old refcount structure is leaked (it will be covered by the |
| * new refcount structure). |
| */ |
| static int rebuild_refcount_structure(BlockDriverState *bs, |
| BdrvCheckResult *res, |
| void **refcount_table, |
| int64_t *nb_clusters) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int64_t first_free_cluster = 0, reftable_offset = -1, cluster = 0; |
| int64_t refblock_offset, refblock_start, refblock_index; |
| uint32_t reftable_size = 0; |
| uint64_t *on_disk_reftable = NULL; |
| void *on_disk_refblock; |
| int ret = 0; |
| struct { |
| uint64_t reftable_offset; |
| uint32_t reftable_clusters; |
| } QEMU_PACKED reftable_offset_and_clusters; |
| |
| qcow2_cache_empty(bs, s->refcount_block_cache); |
| |
| write_refblocks: |
| for (; cluster < *nb_clusters; cluster++) { |
| if (!s->get_refcount(*refcount_table, cluster)) { |
| continue; |
| } |
| |
| refblock_index = cluster >> s->refcount_block_bits; |
| refblock_start = refblock_index << s->refcount_block_bits; |
| |
| /* Don't allocate a cluster in a refblock already written to disk */ |
| if (first_free_cluster < refblock_start) { |
| first_free_cluster = refblock_start; |
| } |
| refblock_offset = alloc_clusters_imrt(bs, 1, refcount_table, |
| nb_clusters, &first_free_cluster); |
| if (refblock_offset < 0) { |
| fprintf(stderr, "ERROR allocating refblock: %s\n", |
| strerror(-refblock_offset)); |
| res->check_errors++; |
| ret = refblock_offset; |
| goto fail; |
| } |
| |
| if (reftable_size <= refblock_index) { |
| uint32_t old_reftable_size = reftable_size; |
| uint64_t *new_on_disk_reftable; |
| |
| reftable_size = ROUND_UP((refblock_index + 1) * sizeof(uint64_t), |
| s->cluster_size) / sizeof(uint64_t); |
| new_on_disk_reftable = g_try_realloc(on_disk_reftable, |
| reftable_size * |
| sizeof(uint64_t)); |
| if (!new_on_disk_reftable) { |
| res->check_errors++; |
| ret = -ENOMEM; |
| goto fail; |
| } |
| on_disk_reftable = new_on_disk_reftable; |
| |
| memset(on_disk_reftable + old_reftable_size, 0, |
| (reftable_size - old_reftable_size) * sizeof(uint64_t)); |
| |
| /* The offset we have for the reftable is now no longer valid; |
| * this will leak that range, but we can easily fix that by running |
| * a leak-fixing check after this rebuild operation */ |
| reftable_offset = -1; |
| } |
| on_disk_reftable[refblock_index] = refblock_offset; |
| |
| /* If this is apparently the last refblock (for now), try to squeeze the |
| * reftable in */ |
| if (refblock_index == (*nb_clusters - 1) >> s->refcount_block_bits && |
| reftable_offset < 0) |
| { |
| uint64_t reftable_clusters = size_to_clusters(s, reftable_size * |
| sizeof(uint64_t)); |
| reftable_offset = alloc_clusters_imrt(bs, reftable_clusters, |
| refcount_table, nb_clusters, |
| &first_free_cluster); |
| if (reftable_offset < 0) { |
| fprintf(stderr, "ERROR allocating reftable: %s\n", |
| strerror(-reftable_offset)); |
| res->check_errors++; |
| ret = reftable_offset; |
| goto fail; |
| } |
| } |
| |
| ret = qcow2_pre_write_overlap_check(bs, 0, refblock_offset, |
| s->cluster_size); |
| if (ret < 0) { |
| fprintf(stderr, "ERROR writing refblock: %s\n", strerror(-ret)); |
| goto fail; |
| } |
| |
| /* The size of *refcount_table is always cluster-aligned, therefore the |
| * write operation will not overflow */ |
| on_disk_refblock = (void *)((char *) *refcount_table + |
| refblock_index * s->cluster_size); |
| |
| ret = bdrv_write(bs->file->bs, refblock_offset / BDRV_SECTOR_SIZE, |
| on_disk_refblock, s->cluster_sectors); |
| if (ret < 0) { |
| fprintf(stderr, "ERROR writing refblock: %s\n", strerror(-ret)); |
| goto fail; |
| } |
| |
| /* Go to the end of this refblock */ |
| cluster = refblock_start + s->refcount_block_size - 1; |
| } |
| |
| if (reftable_offset < 0) { |
| uint64_t post_refblock_start, reftable_clusters; |
| |
| post_refblock_start = ROUND_UP(*nb_clusters, s->refcount_block_size); |
| reftable_clusters = size_to_clusters(s, |
| reftable_size * sizeof(uint64_t)); |
| /* Not pretty but simple */ |
| if (first_free_cluster < post_refblock_start) { |
| first_free_cluster = post_refblock_start; |
| } |
| reftable_offset = alloc_clusters_imrt(bs, reftable_clusters, |
| refcount_table, nb_clusters, |
| &first_free_cluster); |
| if (reftable_offset < 0) { |
| fprintf(stderr, "ERROR allocating reftable: %s\n", |
| strerror(-reftable_offset)); |
| res->check_errors++; |
| ret = reftable_offset; |
| goto fail; |
| } |
| |
| goto write_refblocks; |
| } |
| |
| assert(on_disk_reftable); |
| |
| for (refblock_index = 0; refblock_index < reftable_size; refblock_index++) { |
| cpu_to_be64s(&on_disk_reftable[refblock_index]); |
| } |
| |
| ret = qcow2_pre_write_overlap_check(bs, 0, reftable_offset, |
| reftable_size * sizeof(uint64_t)); |
| if (ret < 0) { |
| fprintf(stderr, "ERROR writing reftable: %s\n", strerror(-ret)); |
| goto fail; |
| } |
| |
| assert(reftable_size < INT_MAX / sizeof(uint64_t)); |
| ret = bdrv_pwrite(bs->file->bs, reftable_offset, on_disk_reftable, |
| reftable_size * sizeof(uint64_t)); |
| if (ret < 0) { |
| fprintf(stderr, "ERROR writing reftable: %s\n", strerror(-ret)); |
| goto fail; |
| } |
| |
| /* Enter new reftable into the image header */ |
| cpu_to_be64w(&reftable_offset_and_clusters.reftable_offset, |
| reftable_offset); |
| cpu_to_be32w(&reftable_offset_and_clusters.reftable_clusters, |
| size_to_clusters(s, reftable_size * sizeof(uint64_t))); |
| ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, |
| refcount_table_offset), |
| &reftable_offset_and_clusters, |
| sizeof(reftable_offset_and_clusters)); |
| if (ret < 0) { |
| fprintf(stderr, "ERROR setting reftable: %s\n", strerror(-ret)); |
| goto fail; |
| } |
| |
| for (refblock_index = 0; refblock_index < reftable_size; refblock_index++) { |
| be64_to_cpus(&on_disk_reftable[refblock_index]); |
| } |
| s->refcount_table = on_disk_reftable; |
| s->refcount_table_offset = reftable_offset; |
| s->refcount_table_size = reftable_size; |
| |
| return 0; |
| |
| fail: |
| g_free(on_disk_reftable); |
| return ret; |
| } |
| |
| /* |
| * Checks an image for refcount consistency. |
| * |
| * Returns 0 if no errors are found, the number of errors in case the image is |
| * detected as corrupted, and -errno when an internal error occurred. |
| */ |
| int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res, |
| BdrvCheckMode fix) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| BdrvCheckResult pre_compare_res; |
| int64_t size, highest_cluster, nb_clusters; |
| void *refcount_table = NULL; |
| bool rebuild = false; |
| int ret; |
| |
| size = bdrv_getlength(bs->file->bs); |
| if (size < 0) { |
| res->check_errors++; |
| return size; |
| } |
| |
| nb_clusters = size_to_clusters(s, size); |
| if (nb_clusters > INT_MAX) { |
| res->check_errors++; |
| return -EFBIG; |
| } |
| |
| res->bfi.total_clusters = |
| size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE); |
| |
| ret = calculate_refcounts(bs, res, fix, &rebuild, &refcount_table, |
| &nb_clusters); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| /* In case we don't need to rebuild the refcount structure (but want to fix |
| * something), this function is immediately called again, in which case the |
| * result should be ignored */ |
| pre_compare_res = *res; |
| compare_refcounts(bs, res, 0, &rebuild, &highest_cluster, refcount_table, |
| nb_clusters); |
| |
| if (rebuild && (fix & BDRV_FIX_ERRORS)) { |
| BdrvCheckResult old_res = *res; |
| int fresh_leaks = 0; |
| |
| fprintf(stderr, "Rebuilding refcount structure\n"); |
| ret = rebuild_refcount_structure(bs, res, &refcount_table, |
| &nb_clusters); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| res->corruptions = 0; |
| res->leaks = 0; |
| |
| /* Because the old reftable has been exchanged for a new one the |
| * references have to be recalculated */ |
| rebuild = false; |
| memset(refcount_table, 0, refcount_array_byte_size(s, nb_clusters)); |
| ret = calculate_refcounts(bs, res, 0, &rebuild, &refcount_table, |
| &nb_clusters); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| if (fix & BDRV_FIX_LEAKS) { |
| /* The old refcount structures are now leaked, fix it; the result |
| * can be ignored, aside from leaks which were introduced by |
| * rebuild_refcount_structure() that could not be fixed */ |
| BdrvCheckResult saved_res = *res; |
| *res = (BdrvCheckResult){ 0 }; |
| |
| compare_refcounts(bs, res, BDRV_FIX_LEAKS, &rebuild, |
| &highest_cluster, refcount_table, nb_clusters); |
| if (rebuild) { |
| fprintf(stderr, "ERROR rebuilt refcount structure is still " |
| "broken\n"); |
| } |
| |
| /* Any leaks accounted for here were introduced by |
| * rebuild_refcount_structure() because that function has created a |
| * new refcount structure from scratch */ |
| fresh_leaks = res->leaks; |
| *res = saved_res; |
| } |
| |
| if (res->corruptions < old_res.corruptions) { |
| res->corruptions_fixed += old_res.corruptions - res->corruptions; |
| } |
| if (res->leaks < old_res.leaks) { |
| res->leaks_fixed += old_res.leaks - res->leaks; |
| } |
| res->leaks += fresh_leaks; |
| } else if (fix) { |
| if (rebuild) { |
| fprintf(stderr, "ERROR need to rebuild refcount structures\n"); |
| res->check_errors++; |
| ret = -EIO; |
| goto fail; |
| } |
| |
| if (res->leaks || res->corruptions) { |
| *res = pre_compare_res; |
| compare_refcounts(bs, res, fix, &rebuild, &highest_cluster, |
| refcount_table, nb_clusters); |
| } |
| } |
| |
| /* check OFLAG_COPIED */ |
| ret = check_oflag_copied(bs, res, fix); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| res->image_end_offset = (highest_cluster + 1) * s->cluster_size; |
| ret = 0; |
| |
| fail: |
| g_free(refcount_table); |
| |
| return ret; |
| } |
| |
| #define overlaps_with(ofs, sz) \ |
| ranges_overlap(offset, size, ofs, sz) |
| |
| /* |
| * Checks if the given offset into the image file is actually free to use by |
| * looking for overlaps with important metadata sections (L1/L2 tables etc.), |
| * i.e. a sanity check without relying on the refcount tables. |
| * |
| * The ign parameter specifies what checks not to perform (being a bitmask of |
| * QCow2MetadataOverlap values), i.e., what sections to ignore. |
| * |
| * Returns: |
| * - 0 if writing to this offset will not affect the mentioned metadata |
| * - a positive QCow2MetadataOverlap value indicating one overlapping section |
| * - a negative value (-errno) indicating an error while performing a check, |
| * e.g. when bdrv_read failed on QCOW2_OL_INACTIVE_L2 |
| */ |
| int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset, |
| int64_t size) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int chk = s->overlap_check & ~ign; |
| int i, j; |
| |
| if (!size) { |
| return 0; |
| } |
| |
| if (chk & QCOW2_OL_MAIN_HEADER) { |
| if (offset < s->cluster_size) { |
| return QCOW2_OL_MAIN_HEADER; |
| } |
| } |
| |
| /* align range to test to cluster boundaries */ |
| size = align_offset(offset_into_cluster(s, offset) + size, s->cluster_size); |
| offset = start_of_cluster(s, offset); |
| |
| if ((chk & QCOW2_OL_ACTIVE_L1) && s->l1_size) { |
| if (overlaps_with(s->l1_table_offset, s->l1_size * sizeof(uint64_t))) { |
| return QCOW2_OL_ACTIVE_L1; |
| } |
| } |
| |
| if ((chk & QCOW2_OL_REFCOUNT_TABLE) && s->refcount_table_size) { |
| if (overlaps_with(s->refcount_table_offset, |
| s->refcount_table_size * sizeof(uint64_t))) { |
| return QCOW2_OL_REFCOUNT_TABLE; |
| } |
| } |
| |
| if ((chk & QCOW2_OL_SNAPSHOT_TABLE) && s->snapshots_size) { |
| if (overlaps_with(s->snapshots_offset, s->snapshots_size)) { |
| return QCOW2_OL_SNAPSHOT_TABLE; |
| } |
| } |
| |
| if ((chk & QCOW2_OL_INACTIVE_L1) && s->snapshots) { |
| for (i = 0; i < s->nb_snapshots; i++) { |
| if (s->snapshots[i].l1_size && |
| overlaps_with(s->snapshots[i].l1_table_offset, |
| s->snapshots[i].l1_size * sizeof(uint64_t))) { |
| return QCOW2_OL_INACTIVE_L1; |
| } |
| } |
| } |
| |
| if ((chk & QCOW2_OL_ACTIVE_L2) && s->l1_table) { |
| for (i = 0; i < s->l1_size; i++) { |
| if ((s->l1_table[i] & L1E_OFFSET_MASK) && |
| overlaps_with(s->l1_table[i] & L1E_OFFSET_MASK, |
| s->cluster_size)) { |
| return QCOW2_OL_ACTIVE_L2; |
| } |
| } |
| } |
| |
| if ((chk & QCOW2_OL_REFCOUNT_BLOCK) && s->refcount_table) { |
| for (i = 0; i < s->refcount_table_size; i++) { |
| if ((s->refcount_table[i] & REFT_OFFSET_MASK) && |
| overlaps_with(s->refcount_table[i] & REFT_OFFSET_MASK, |
| s->cluster_size)) { |
| return QCOW2_OL_REFCOUNT_BLOCK; |
| } |
| } |
| } |
| |
| if ((chk & QCOW2_OL_INACTIVE_L2) && s->snapshots) { |
| for (i = 0; i < s->nb_snapshots; i++) { |
| uint64_t l1_ofs = s->snapshots[i].l1_table_offset; |
| uint32_t l1_sz = s->snapshots[i].l1_size; |
| uint64_t l1_sz2 = l1_sz * sizeof(uint64_t); |
| uint64_t *l1 = g_try_malloc(l1_sz2); |
| int ret; |
| |
| if (l1_sz2 && l1 == NULL) { |
| return -ENOMEM; |
| } |
| |
| ret = bdrv_pread(bs->file->bs, l1_ofs, l1, l1_sz2); |
| if (ret < 0) { |
| g_free(l1); |
| return ret; |
| } |
| |
| for (j = 0; j < l1_sz; j++) { |
| uint64_t l2_ofs = be64_to_cpu(l1[j]) & L1E_OFFSET_MASK; |
| if (l2_ofs && overlaps_with(l2_ofs, s->cluster_size)) { |
| g_free(l1); |
| return QCOW2_OL_INACTIVE_L2; |
| } |
| } |
| |
| g_free(l1); |
| } |
| } |
| |
| return 0; |
| } |
| |
| static const char *metadata_ol_names[] = { |
| [QCOW2_OL_MAIN_HEADER_BITNR] = "qcow2_header", |
| [QCOW2_OL_ACTIVE_L1_BITNR] = "active L1 table", |
| [QCOW2_OL_ACTIVE_L2_BITNR] = "active L2 table", |
| [QCOW2_OL_REFCOUNT_TABLE_BITNR] = "refcount table", |
| [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = "refcount block", |
| [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = "snapshot table", |
| [QCOW2_OL_INACTIVE_L1_BITNR] = "inactive L1 table", |
| [QCOW2_OL_INACTIVE_L2_BITNR] = "inactive L2 table", |
| }; |
| |
| /* |
| * First performs a check for metadata overlaps (through |
| * qcow2_check_metadata_overlap); if that fails with a negative value (error |
| * while performing a check), that value is returned. If an impending overlap |
| * is detected, the BDS will be made unusable, the qcow2 file marked corrupt |
| * and -EIO returned. |
| * |
| * Returns 0 if there were neither overlaps nor errors while checking for |
| * overlaps; or a negative value (-errno) on error. |
| */ |
| int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset, |
| int64_t size) |
| { |
| int ret = qcow2_check_metadata_overlap(bs, ign, offset, size); |
| |
| if (ret < 0) { |
| return ret; |
| } else if (ret > 0) { |
| int metadata_ol_bitnr = ctz32(ret); |
| assert(metadata_ol_bitnr < QCOW2_OL_MAX_BITNR); |
| |
| qcow2_signal_corruption(bs, true, offset, size, "Preventing invalid " |
| "write on metadata (overlaps with %s)", |
| metadata_ol_names[metadata_ol_bitnr]); |
| return -EIO; |
| } |
| |
| return 0; |
| } |
| |
| /* A pointer to a function of this type is given to walk_over_reftable(). That |
| * function will create refblocks and pass them to a RefblockFinishOp once they |
| * are completed (@refblock). @refblock_empty is set if the refblock is |
| * completely empty. |
| * |
| * Along with the refblock, a corresponding reftable entry is passed, in the |
| * reftable @reftable (which may be reallocated) at @reftable_index. |
| * |
| * @allocated should be set to true if a new cluster has been allocated. |
| */ |
| typedef int (RefblockFinishOp)(BlockDriverState *bs, uint64_t **reftable, |
| uint64_t reftable_index, uint64_t *reftable_size, |
| void *refblock, bool refblock_empty, |
| bool *allocated, Error **errp); |
| |
| /** |
| * This "operation" for walk_over_reftable() allocates the refblock on disk (if |
| * it is not empty) and inserts its offset into the new reftable. The size of |
| * this new reftable is increased as required. |
| */ |
| static int alloc_refblock(BlockDriverState *bs, uint64_t **reftable, |
| uint64_t reftable_index, uint64_t *reftable_size, |
| void *refblock, bool refblock_empty, bool *allocated, |
| Error **errp) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int64_t offset; |
| |
| if (!refblock_empty && reftable_index >= *reftable_size) { |
| uint64_t *new_reftable; |
| uint64_t new_reftable_size; |
| |
| new_reftable_size = ROUND_UP(reftable_index + 1, |
| s->cluster_size / sizeof(uint64_t)); |
| if (new_reftable_size > QCOW_MAX_REFTABLE_SIZE / sizeof(uint64_t)) { |
| error_setg(errp, |
| "This operation would make the refcount table grow " |
| "beyond the maximum size supported by QEMU, aborting"); |
| return -ENOTSUP; |
| } |
| |
| new_reftable = g_try_realloc(*reftable, new_reftable_size * |
| sizeof(uint64_t)); |
| if (!new_reftable) { |
| error_setg(errp, "Failed to increase reftable buffer size"); |
| return -ENOMEM; |
| } |
| |
| memset(new_reftable + *reftable_size, 0, |
| (new_reftable_size - *reftable_size) * sizeof(uint64_t)); |
| |
| *reftable = new_reftable; |
| *reftable_size = new_reftable_size; |
| } |
| |
| if (!refblock_empty && !(*reftable)[reftable_index]) { |
| offset = qcow2_alloc_clusters(bs, s->cluster_size); |
| if (offset < 0) { |
| error_setg_errno(errp, -offset, "Failed to allocate refblock"); |
| return offset; |
| } |
| (*reftable)[reftable_index] = offset; |
| *allocated = true; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * This "operation" for walk_over_reftable() writes the refblock to disk at the |
| * offset specified by the new reftable's entry. It does not modify the new |
| * reftable or change any refcounts. |
| */ |
| static int flush_refblock(BlockDriverState *bs, uint64_t **reftable, |
| uint64_t reftable_index, uint64_t *reftable_size, |
| void *refblock, bool refblock_empty, bool *allocated, |
| Error **errp) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| int64_t offset; |
| int ret; |
| |
| if (reftable_index < *reftable_size && (*reftable)[reftable_index]) { |
| offset = (*reftable)[reftable_index]; |
| |
| ret = qcow2_pre_write_overlap_check(bs, 0, offset, s->cluster_size); |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, "Overlap check failed"); |
| return ret; |
| } |
| |
| ret = bdrv_pwrite(bs->file->bs, offset, refblock, s->cluster_size); |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, "Failed to write refblock"); |
| return ret; |
| } |
| } else { |
| assert(refblock_empty); |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * This function walks over the existing reftable and every referenced refblock; |
| * if @new_set_refcount is non-NULL, it is called for every refcount entry to |
| * create an equal new entry in the passed @new_refblock. Once that |
| * @new_refblock is completely filled, @operation will be called. |
| * |
| * @status_cb and @cb_opaque are used for the amend operation's status callback. |
| * @index is the index of the walk_over_reftable() calls and @total is the total |
| * number of walk_over_reftable() calls per amend operation. Both are used for |
| * calculating the parameters for the status callback. |
| * |
| * @allocated is set to true if a new cluster has been allocated. |
| */ |
| static int walk_over_reftable(BlockDriverState *bs, uint64_t **new_reftable, |
| uint64_t *new_reftable_index, |
| uint64_t *new_reftable_size, |
| void *new_refblock, int new_refblock_size, |
| int new_refcount_bits, |
| RefblockFinishOp *operation, bool *allocated, |
| Qcow2SetRefcountFunc *new_set_refcount, |
| BlockDriverAmendStatusCB *status_cb, |
| void *cb_opaque, int index, int total, |
| Error **errp) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| uint64_t reftable_index; |
| bool new_refblock_empty = true; |
| int refblock_index; |
| int new_refblock_index = 0; |
| int ret; |
| |
| for (reftable_index = 0; reftable_index < s->refcount_table_size; |
| reftable_index++) |
| { |
| uint64_t refblock_offset = s->refcount_table[reftable_index] |
| & REFT_OFFSET_MASK; |
| |
| status_cb(bs, (uint64_t)index * s->refcount_table_size + reftable_index, |
| (uint64_t)total * s->refcount_table_size, cb_opaque); |
| |
| if (refblock_offset) { |
| void *refblock; |
| |
| if (offset_into_cluster(s, refblock_offset)) { |
| qcow2_signal_corruption(bs, true, -1, -1, "Refblock offset %#" |
| PRIx64 " unaligned (reftable index: %#" |
| PRIx64 ")", refblock_offset, |
| reftable_index); |
| error_setg(errp, |
| "Image is corrupt (unaligned refblock offset)"); |
| return -EIO; |
| } |
| |
| ret = qcow2_cache_get(bs, s->refcount_block_cache, refblock_offset, |
| &refblock); |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, "Failed to retrieve refblock"); |
| return ret; |
| } |
| |
| for (refblock_index = 0; refblock_index < s->refcount_block_size; |
| refblock_index++) |
| { |
| uint64_t refcount; |
| |
| if (new_refblock_index >= new_refblock_size) { |
| /* new_refblock is now complete */ |
| ret = operation(bs, new_reftable, *new_reftable_index, |
| new_reftable_size, new_refblock, |
| new_refblock_empty, allocated, errp); |
| if (ret < 0) { |
| qcow2_cache_put(bs, s->refcount_block_cache, &refblock); |
| return ret; |
| } |
| |
| (*new_reftable_index)++; |
| new_refblock_index = 0; |
| new_refblock_empty = true; |
| } |
| |
| refcount = s->get_refcount(refblock, refblock_index); |
| if (new_refcount_bits < 64 && refcount >> new_refcount_bits) { |
| uint64_t offset; |
| |
| qcow2_cache_put(bs, s->refcount_block_cache, &refblock); |
| |
| offset = ((reftable_index << s->refcount_block_bits) |
| + refblock_index) << s->cluster_bits; |
| |
| error_setg(errp, "Cannot decrease refcount entry width to " |
| "%i bits: Cluster at offset %#" PRIx64 " has a " |
| "refcount of %" PRIu64, new_refcount_bits, |
| offset, refcount); |
| return -EINVAL; |
| } |
| |
| if (new_set_refcount) { |
| new_set_refcount(new_refblock, new_refblock_index++, |
| refcount); |
| } else { |
| new_refblock_index++; |
| } |
| new_refblock_empty = new_refblock_empty && refcount == 0; |
| } |
| |
| qcow2_cache_put(bs, s->refcount_block_cache, &refblock); |
| } else { |
| /* No refblock means every refcount is 0 */ |
| for (refblock_index = 0; refblock_index < s->refcount_block_size; |
| refblock_index++) |
| { |
| if (new_refblock_index >= new_refblock_size) { |
| /* new_refblock is now complete */ |
| ret = operation(bs, new_reftable, *new_reftable_index, |
| new_reftable_size, new_refblock, |
| new_refblock_empty, allocated, errp); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| (*new_reftable_index)++; |
| new_refblock_index = 0; |
| new_refblock_empty = true; |
| } |
| |
| if (new_set_refcount) { |
| new_set_refcount(new_refblock, new_refblock_index++, 0); |
| } else { |
| new_refblock_index++; |
| } |
| } |
| } |
| } |
| |
| if (new_refblock_index > 0) { |
| /* Complete the potentially existing partially filled final refblock */ |
| if (new_set_refcount) { |
| for (; new_refblock_index < new_refblock_size; |
| new_refblock_index++) |
| { |
| new_set_refcount(new_refblock, new_refblock_index, 0); |
| } |
| } |
| |
| ret = operation(bs, new_reftable, *new_reftable_index, |
| new_reftable_size, new_refblock, new_refblock_empty, |
| allocated, errp); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| (*new_reftable_index)++; |
| } |
| |
| status_cb(bs, (uint64_t)(index + 1) * s->refcount_table_size, |
| (uint64_t)total * s->refcount_table_size, cb_opaque); |
| |
| return 0; |
| } |
| |
| int qcow2_change_refcount_order(BlockDriverState *bs, int refcount_order, |
| BlockDriverAmendStatusCB *status_cb, |
| void *cb_opaque, Error **errp) |
| { |
| BDRVQcow2State *s = bs->opaque; |
| Qcow2GetRefcountFunc *new_get_refcount; |
| Qcow2SetRefcountFunc *new_set_refcount; |
| void *new_refblock = qemu_blockalign(bs->file->bs, s->cluster_size); |
| uint64_t *new_reftable = NULL, new_reftable_size = 0; |
| uint64_t *old_reftable, old_reftable_size, old_reftable_offset; |
| uint64_t new_reftable_index = 0; |
| uint64_t i; |
| int64_t new_reftable_offset = 0, allocated_reftable_size = 0; |
| int new_refblock_size, new_refcount_bits = 1 << refcount_order; |
| int old_refcount_order; |
| int walk_index = 0; |
| int ret; |
| bool new_allocation; |
| |
| assert(s->qcow_version >= 3); |
| assert(refcount_order >= 0 && refcount_order <= 6); |
| |
| /* see qcow2_open() */ |
| new_refblock_size = 1 << (s->cluster_bits - (refcount_order - 3)); |
| |
| new_get_refcount = get_refcount_funcs[refcount_order]; |
| new_set_refcount = set_refcount_funcs[refcount_order]; |
| |
| |
| do { |
| int total_walks; |
| |
| new_allocation = false; |
| |
| /* At least we have to do this walk and the one which writes the |
| * refblocks; also, at least we have to do this loop here at least |
| * twice (normally), first to do the allocations, and second to |
| * determine that everything is correctly allocated, this then makes |
| * three walks in total */ |
| total_walks = MAX(walk_index + 2, 3); |
| |
| /* First, allocate the structures so they are present in the refcount |
| * structures */ |
| ret = walk_over_reftable(bs, &new_reftable, &new_reftable_index, |
| &new_reftable_size, NULL, new_refblock_size, |
| new_refcount_bits, &alloc_refblock, |
| &new_allocation, NULL, status_cb, cb_opaque, |
| walk_index++, total_walks, errp); |
| if (ret < 0) { |
| goto done; |
| } |
| |
| new_reftable_index = 0; |
| |
| if (new_allocation) { |
| if (new_reftable_offset) { |
| qcow2_free_clusters(bs, new_reftable_offset, |
| allocated_reftable_size * sizeof(uint64_t), |
| QCOW2_DISCARD_NEVER); |
| } |
| |
| new_reftable_offset = qcow2_alloc_clusters(bs, new_reftable_size * |
| sizeof(uint64_t)); |
| if (new_reftable_offset < 0) { |
| error_setg_errno(errp, -new_reftable_offset, |
| "Failed to allocate the new reftable"); |
| ret = new_reftable_offset; |
| goto done; |
| } |
| allocated_reftable_size = new_reftable_size; |
| } |
| } while (new_allocation); |
| |
| /* Second, write the new refblocks */ |
| ret = walk_over_reftable(bs, &new_reftable, &new_reftable_index, |
| &new_reftable_size, new_refblock, |
| new_refblock_size, new_refcount_bits, |
| &flush_refblock, &new_allocation, new_set_refcount, |
| status_cb, cb_opaque, walk_index, walk_index + 1, |
| errp); |
| if (ret < 0) { |
| goto done; |
| } |
| assert(!new_allocation); |
| |
| |
| /* Write the new reftable */ |
| ret = qcow2_pre_write_overlap_check(bs, 0, new_reftable_offset, |
| new_reftable_size * sizeof(uint64_t)); |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, "Overlap check failed"); |
| goto done; |
| } |
| |
| for (i = 0; i < new_reftable_size; i++) { |
| cpu_to_be64s(&new_reftable[i]); |
| } |
| |
| ret = bdrv_pwrite(bs->file->bs, new_reftable_offset, new_reftable, |
| new_reftable_size * sizeof(uint64_t)); |
| |
| for (i = 0; i < new_reftable_size; i++) { |
| be64_to_cpus(&new_reftable[i]); |
| } |
| |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, "Failed to write the new reftable"); |
| goto done; |
| } |
| |
| |
| /* Empty the refcount cache */ |
| ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
| if (ret < 0) { |
| error_setg_errno(errp, -ret, "Failed to flush the refblock cache"); |
| goto done; |
| } |
| |
| /* Update the image header to point to the new reftable; this only updates |
| * the fields which are relevant to qcow2_update_header(); other fields |
| * such as s->refcount_table or s->refcount_bits stay stale for now |
| * (because we have to restore everything if qcow2_update_header() fails) */ |
| old_refcount_order = s->refcount_order; |
| old_reftable_size = s->refcount_table_size; |
| old_reftable_offset = s->refcount_table_offset; |
| |
| s->refcount_order = refcount_order; |
| s->refcount_table_size = new_reftable_size; |
| s->refcount_table_offset = new_reftable_offset; |
| |
| ret = qcow2_update_header(bs); |
| if (ret < 0) { |
| s->refcount_order = old_refcount_order; |
| s->refcount_table_size = old_reftable_size; |
| s->refcount_table_offset = old_reftable_offset; |
| error_setg_errno(errp, -ret, "Failed to update the qcow2 header"); |
| goto done; |
| } |
| |
| /* Now update the rest of the in-memory information */ |
| old_reftable = s->refcount_table; |
| s->refcount_table = new_reftable; |
| |
| s->refcount_bits = 1 << refcount_order; |
| s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); |
| s->refcount_max += s->refcount_max - 1; |
| |
| s->refcount_block_bits = s->cluster_bits - (refcount_order - 3); |
| s->refcount_block_size = 1 << s->refcount_block_bits; |
| |
| s->get_refcount = new_get_refcount; |
| s->set_refcount = new_set_refcount; |
| |
| /* For cleaning up all old refblocks and the old reftable below the "done" |
| * label */ |
| new_reftable = old_reftable; |
| new_reftable_size = old_reftable_size; |
| new_reftable_offset = old_reftable_offset; |
| |
| done: |
| if (new_reftable) { |
| /* On success, new_reftable actually points to the old reftable (and |
| * new_reftable_size is the old reftable's size); but that is just |
| * fine */ |
| for (i = 0; i < new_reftable_size; i++) { |
| uint64_t offset = new_reftable[i] & REFT_OFFSET_MASK; |
| if (offset) { |
| qcow2_free_clusters(bs, offset, s->cluster_size, |
| QCOW2_DISCARD_OTHER); |
| } |
| } |
| g_free(new_reftable); |
| |
| if (new_reftable_offset > 0) { |
| qcow2_free_clusters(bs, new_reftable_offset, |
| new_reftable_size * sizeof(uint64_t), |
| QCOW2_DISCARD_OTHER); |
| } |
| } |
| |
| qemu_vfree(new_refblock); |
| return ret; |
| } |