diff options
Diffstat (limited to 'qemu/block/qcow2-refcount.c')
| -rw-r--r-- | qemu/block/qcow2-refcount.c | 2921 |
1 files changed, 0 insertions, 2921 deletions
diff --git a/qemu/block/qcow2-refcount.c b/qemu/block/qcow2-refcount.c deleted file mode 100644 index ca6094ff5..000000000 --- a/qemu/block/qcow2-refcount.c +++ /dev/null @@ -1,2921 +0,0 @@ -/* - * 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/osdep.h" -#include "qapi/error.h" -#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; -} |