diff options
Diffstat (limited to 'contrib/qemu/block/qcow2-refcount.c')
| -rw-r--r-- | contrib/qemu/block/qcow2-refcount.c | 1374 |
1 files changed, 0 insertions, 1374 deletions
diff --git a/contrib/qemu/block/qcow2-refcount.c b/contrib/qemu/block/qcow2-refcount.c deleted file mode 100644 index 1244693f39e..00000000000 --- a/contrib/qemu/block/qcow2-refcount.c +++ /dev/null @@ -1,1374 +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-common.h" -#include "block/block_int.h" -#include "block/qcow2.h" - -static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size); -static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, - int64_t offset, int64_t length, - int addend, enum qcow2_discard_type type); - - -/*********************************************************/ -/* refcount handling */ - -int qcow2_refcount_init(BlockDriverState *bs) -{ - BDRVQcowState *s = bs->opaque; - int ret, refcount_table_size2, i; - - refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t); - s->refcount_table = g_malloc(refcount_table_size2); - if (s->refcount_table_size > 0) { - BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_LOAD); - ret = bdrv_pread(bs->file, s->refcount_table_offset, - s->refcount_table, refcount_table_size2); - if (ret != refcount_table_size2) - goto fail; - for(i = 0; i < s->refcount_table_size; i++) - be64_to_cpus(&s->refcount_table[i]); - } - return 0; - fail: - return -ENOMEM; -} - -void qcow2_refcount_close(BlockDriverState *bs) -{ - BDRVQcowState *s = bs->opaque; - g_free(s->refcount_table); -} - - -static int load_refcount_block(BlockDriverState *bs, - int64_t refcount_block_offset, - void **refcount_block) -{ - BDRVQcowState *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; -} - -/* - * Returns the refcount of the cluster given by its index. Any non-negative - * return value is the refcount of the cluster, negative values are -errno - * and indicate an error. - */ -static int get_refcount(BlockDriverState *bs, int64_t cluster_index) -{ - BDRVQcowState *s = bs->opaque; - int refcount_table_index, block_index; - int64_t refcount_block_offset; - int ret; - uint16_t *refcount_block; - uint16_t refcount; - - refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); - if (refcount_table_index >= s->refcount_table_size) - return 0; - refcount_block_offset = s->refcount_table[refcount_table_index]; - if (!refcount_block_offset) - return 0; - - ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset, - (void**) &refcount_block); - if (ret < 0) { - return ret; - } - - block_index = cluster_index & - ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); - refcount = be16_to_cpu(refcount_block[block_index]); - - ret = qcow2_cache_put(bs, s->refcount_block_cache, - (void**) &refcount_block); - if (ret < 0) { - return ret; - } - - return refcount; -} - -/* - * 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(BDRVQcowState *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(BDRVQcowState *s, uint64_t offset_a, - uint64_t offset_b) -{ - uint64_t block_a = offset_a >> (2 * s->cluster_bits - REFCOUNT_SHIFT); - uint64_t block_b = offset_b >> (2 * s->cluster_bits - REFCOUNT_SHIFT); - - 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, uint16_t **refcount_block) -{ - BDRVQcowState *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->cluster_bits - REFCOUNT_SHIFT); - - 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) { - return load_refcount_block(bs, refcount_block_offset, - (void**) 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 doing the initial refcount increase. This means that some clusters - * have already been allocated by the caller, but their refcount isn't - * accurate yet. free_cluster_index tells us where this allocation ends - * as long as we don't overwrite it by freeing 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, - (void**) 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) & - ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); - (*refcount_block)[block_index] = cpu_to_be16(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, - 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, - (void**) 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(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, - 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; - return 0; - } - - ret = qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block); - if (ret < 0) { - goto fail_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 */ - uint64_t refcount_block_clusters = 1 << (s->cluster_bits - REFCOUNT_SHIFT); - uint64_t blocks_used = (s->free_cluster_index + - refcount_block_clusters - 1) / refcount_block_clusters; - - /* 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 + refcount_block_clusters - 1) - / refcount_block_clusters); - uint64_t meta_clusters = table_clusters + blocks_clusters; - - last_table_size = table_size; - table_size = next_refcount_table_size(s, blocks_used + - ((meta_clusters + refcount_block_clusters - 1) - / refcount_block_clusters)); - - } 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 * refcount_block_clusters) * - s->cluster_size; - uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size; - uint16_t *new_blocks = g_malloc0(blocks_clusters * s->cluster_size); - uint64_t *new_table = g_malloc0(table_size * sizeof(uint64_t)); - - assert(meta_offset >= (s->free_cluster_index * s->cluster_size)); - - /* 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++) { - new_blocks[block++] = cpu_to_be16(1); - } - - /* Write refcount blocks to disk */ - BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS); - ret = bdrv_pwrite_sync(bs->file, meta_offset, new_blocks, - blocks_clusters * s->cluster_size); - g_free(new_blocks); - 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, 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 */ - uint8_t data[12]; - cpu_to_be64w((uint64_t*)data, table_offset); - cpu_to_be32w((uint32_t*)(data + 8), table_clusters); - BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE); - ret = bdrv_pwrite_sync(bs->file, 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. Remember, we must not change free_cluster_index */ - uint64_t old_free_cluster_index = s->free_cluster_index; - qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t), - QCOW2_DISCARD_OTHER); - s->free_cluster_index = old_free_cluster_index; - - ret = load_refcount_block(bs, new_block, (void**) refcount_block); - if (ret < 0) { - return ret; - } - - return 0; - -fail_table: - g_free(new_table); -fail_block: - if (*refcount_block != NULL) { - qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block); - } - return ret; -} - -void qcow2_process_discards(BlockDriverState *bs, int ret) -{ - BDRVQcowState *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, - 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) -{ - BDRVQcowState *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; - } -} - -/* XXX: cache several refcount block clusters ? */ -static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, - int64_t offset, int64_t length, int addend, enum qcow2_discard_type type) -{ - BDRVQcowState *s = bs->opaque; - int64_t start, last, cluster_offset; - uint16_t *refcount_block = NULL; - int64_t old_table_index = -1; - int ret; - -#ifdef DEBUG_ALLOC2 - fprintf(stderr, "update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n", - offset, length, addend); -#endif - if (length < 0) { - return -EINVAL; - } else if (length == 0) { - return 0; - } - - if (addend < 0) { - qcow2_cache_set_dependency(bs, s->refcount_block_cache, - s->l2_table_cache); - } - - start = offset & ~(s->cluster_size - 1); - last = (offset + length - 1) & ~(s->cluster_size - 1); - for(cluster_offset = start; cluster_offset <= last; - cluster_offset += s->cluster_size) - { - int block_index, refcount; - int64_t cluster_index = cluster_offset >> s->cluster_bits; - int64_t table_index = - cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); - - /* Load the refcount block and allocate it if needed */ - if (table_index != old_table_index) { - if (refcount_block) { - ret = qcow2_cache_put(bs, s->refcount_block_cache, - (void**) &refcount_block); - if (ret < 0) { - goto fail; - } - } - - ret = alloc_refcount_block(bs, cluster_index, &refcount_block); - if (ret < 0) { - goto fail; - } - } - old_table_index = table_index; - - qcow2_cache_entry_mark_dirty(s->refcount_block_cache, refcount_block); - - /* we can update the count and save it */ - block_index = cluster_index & - ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); - - refcount = be16_to_cpu(refcount_block[block_index]); - refcount += addend; - if (refcount < 0 || refcount > 0xffff) { - ret = -EINVAL; - goto fail; - } - if (refcount == 0 && cluster_index < s->free_cluster_index) { - s->free_cluster_index = cluster_index; - } - refcount_block[block_index] = cpu_to_be16(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) { - int wret; - wret = qcow2_cache_put(bs, s->refcount_block_cache, - (void**) &refcount_block); - if (wret < 0) { - return ret < 0 ? ret : wret; - } - } - - /* - * 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, - QCOW2_DISCARD_NEVER); - (void)dummy; - } - - return ret; -} - -/* - * Increases or decreases the refcount of a given cluster by one. - * addend must be 1 or -1. - * - * If the return value is non-negative, it is the new refcount of the cluster. - * If it is negative, it is -errno and indicates an error. - */ -static int update_cluster_refcount(BlockDriverState *bs, - int64_t cluster_index, - int addend, - enum qcow2_discard_type type) -{ - BDRVQcowState *s = bs->opaque; - int ret; - - ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend, - type); - if (ret < 0) { - return ret; - } - - return get_refcount(bs, cluster_index); -} - - - -/*********************************************************/ -/* cluster allocation functions */ - - - -/* return < 0 if error */ -static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size) -{ - BDRVQcowState *s = bs->opaque; - int i, nb_clusters, refcount; - - nb_clusters = size_to_clusters(s, size); -retry: - for(i = 0; i < nb_clusters; i++) { - int64_t next_cluster_index = s->free_cluster_index++; - refcount = get_refcount(bs, next_cluster_index); - - if (refcount < 0) { - return refcount; - } else if (refcount != 0) { - goto retry; - } - } -#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, int64_t size) -{ - int64_t offset; - int ret; - - BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); - offset = alloc_clusters_noref(bs, size); - if (offset < 0) { - return offset; - } - - ret = update_refcount(bs, offset, size, 1, QCOW2_DISCARD_NEVER); - if (ret < 0) { - return ret; - } - - return offset; -} - -int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, - int nb_clusters) -{ - BDRVQcowState *s = bs->opaque; - uint64_t cluster_index; - uint64_t old_free_cluster_index; - int i, refcount, ret; - - /* Check how many clusters there are free */ - cluster_index = offset >> s->cluster_bits; - for(i = 0; i < nb_clusters; i++) { - refcount = get_refcount(bs, cluster_index++); - - if (refcount < 0) { - return refcount; - } else if (refcount != 0) { - break; - } - } - - /* And then allocate them */ - old_free_cluster_index = s->free_cluster_index; - s->free_cluster_index = cluster_index + i; - - ret = update_refcount(bs, offset, i << s->cluster_bits, 1, - QCOW2_DISCARD_NEVER); - if (ret < 0) { - return ret; - } - - s->free_cluster_index = old_free_cluster_index; - - 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) -{ - BDRVQcowState *s = bs->opaque; - int64_t offset, cluster_offset; - int free_in_cluster; - - BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES); - assert(size > 0 && size <= s->cluster_size); - if (s->free_byte_offset == 0) { - offset = qcow2_alloc_clusters(bs, s->cluster_size); - if (offset < 0) { - return offset; - } - s->free_byte_offset = offset; - } - redo: - free_in_cluster = s->cluster_size - - (s->free_byte_offset & (s->cluster_size - 1)); - if (size <= free_in_cluster) { - /* enough space in current cluster */ - offset = s->free_byte_offset; - s->free_byte_offset += size; - free_in_cluster -= size; - if (free_in_cluster == 0) - s->free_byte_offset = 0; - if ((offset & (s->cluster_size - 1)) != 0) - update_cluster_refcount(bs, offset >> s->cluster_bits, 1, - QCOW2_DISCARD_NEVER); - } else { - offset = qcow2_alloc_clusters(bs, s->cluster_size); - if (offset < 0) { - return offset; - } - cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1); - if ((cluster_offset + s->cluster_size) == offset) { - /* we are lucky: contiguous data */ - offset = s->free_byte_offset; - update_cluster_refcount(bs, offset >> s->cluster_bits, 1, - QCOW2_DISCARD_NEVER); - s->free_byte_offset += size; - } else { - s->free_byte_offset = offset; - goto redo; - } - } - - /* The cluster refcount was incremented, either by qcow2_alloc_clusters() - * or explicitly by update_cluster_refcount(). 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); - 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, 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) -{ - BDRVQcowState *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: - qcow2_free_clusters(bs, l2_entry & L2E_OFFSET_MASK, - nb_clusters << s->cluster_bits, type); - break; - case QCOW2_CLUSTER_UNALLOCATED: - case QCOW2_CLUSTER_ZERO: - 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) -{ - BDRVQcowState *s = bs->opaque; - uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated; - int64_t old_offset, old_l2_offset; - int i, j, l1_modified = 0, nb_csectors, refcount; - int ret; - - 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_malloc0(align_offset(l1_size2, 512)); - l1_allocated = 1; - - ret = bdrv_pread(bs->file, 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 = 0; - } - - 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; - - 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++) { - offset = be64_to_cpu(l2_table[j]); - if (offset != 0) { - old_offset = offset; - offset &= ~QCOW_OFLAG_COPIED; - if (offset & QCOW_OFLAG_COMPRESSED) { - nb_csectors = ((offset >> s->csize_shift) & - s->csize_mask) + 1; - if (addend != 0) { - int ret; - ret = update_refcount(bs, - (offset & s->cluster_offset_mask) & ~511, - nb_csectors * 512, addend, - QCOW2_DISCARD_SNAPSHOT); - if (ret < 0) { - goto fail; - } - } - /* compressed clusters are never modified */ - refcount = 2; - } else { - uint64_t cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits; - if (addend != 0) { - refcount = update_cluster_refcount(bs, cluster_index, addend, - QCOW2_DISCARD_SNAPSHOT); - } else { - refcount = get_refcount(bs, cluster_index); - } - - if (refcount < 0) { - ret = refcount; - goto fail; - } - } - - 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(s->l2_table_cache, l2_table); - } - } - } - - ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); - if (ret < 0) { - goto fail; - } - - - if (addend != 0) { - refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend, - QCOW2_DISCARD_SNAPSHOT); - } else { - refcount = get_refcount(bs, l2_offset >> s->cluster_bits); - } - if (refcount < 0) { - ret = refcount; - 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, 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 */ - - - -/* - * 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 the the refcount table saved in the image. - * - * Modifies the number of errors in res. - */ -static void inc_refcounts(BlockDriverState *bs, - BdrvCheckResult *res, - uint16_t *refcount_table, - int refcount_table_size, - int64_t offset, int64_t size) -{ - BDRVQcowState *s = bs->opaque; - int64_t start, last, cluster_offset; - int k; - - if (size <= 0) - return; - - start = offset & ~(s->cluster_size - 1); - last = (offset + size - 1) & ~(s->cluster_size - 1); - for(cluster_offset = start; cluster_offset <= last; - cluster_offset += s->cluster_size) { - k = cluster_offset >> s->cluster_bits; - if (k < 0) { - fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n", - cluster_offset); - res->corruptions++; - } else if (k >= refcount_table_size) { - fprintf(stderr, "Warning: cluster offset=0x%" PRIx64 " is after " - "the end of the image file, can't properly check refcounts.\n", - cluster_offset); - res->check_errors++; - } else { - if (++refcount_table[k] == 0) { - fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64 - "\n", cluster_offset); - res->corruptions++; - } - } - } -} - -/* Flags for check_refcounts_l1() and check_refcounts_l2() */ -enum { - CHECK_OFLAG_COPIED = 0x1, /* check QCOW_OFLAG_COPIED matches refcount */ - 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, - uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset, - int flags) -{ - BDRVQcowState *s = bs->opaque; - uint64_t *l2_table, l2_entry; - uint64_t next_contiguous_offset = 0; - int i, l2_size, nb_csectors, refcount; - - /* Read L2 table from disk */ - l2_size = s->l2_size * sizeof(uint64_t); - l2_table = g_malloc(l2_size); - - if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size) - 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; - inc_refcounts(bs, res, refcount_table, refcount_table_size, - l2_entry & ~511, nb_csectors * 512); - - 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: - { - /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ - uint64_t offset = l2_entry & L2E_OFFSET_MASK; - - if (flags & CHECK_OFLAG_COPIED) { - refcount = get_refcount(bs, offset >> s->cluster_bits); - if (refcount < 0) { - fprintf(stderr, "Can't get refcount for offset %" - PRIx64 ": %s\n", l2_entry, strerror(-refcount)); - goto fail; - } - if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) { - fprintf(stderr, "ERROR OFLAG_COPIED: offset=%" - PRIx64 " refcount=%d\n", l2_entry, refcount); - res->corruptions++; - } - } - - 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 */ - inc_refcounts(bs, res, refcount_table,refcount_table_size, - offset, s->cluster_size); - - /* Correct offsets are cluster aligned */ - if (offset & (s->cluster_size - 1)) { - 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: - fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n"); - g_free(l2_table); - return -EIO; -} - -/* - * 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, - uint16_t *refcount_table, - int refcount_table_size, - int64_t l1_table_offset, int l1_size, - int flags) -{ - BDRVQcowState *s = bs->opaque; - uint64_t *l1_table, l2_offset, l1_size2; - int i, refcount, ret; - - l1_size2 = l1_size * sizeof(uint64_t); - - /* Mark L1 table as used */ - inc_refcounts(bs, res, refcount_table, refcount_table_size, - l1_table_offset, l1_size2); - - /* Read L1 table entries from disk */ - if (l1_size2 == 0) { - l1_table = NULL; - } else { - l1_table = g_malloc(l1_size2); - if (bdrv_pread(bs->file, l1_table_offset, - l1_table, l1_size2) != l1_size2) - 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) { - /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */ - if (flags & CHECK_OFLAG_COPIED) { - refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) - >> s->cluster_bits); - if (refcount < 0) { - fprintf(stderr, "Can't get refcount for l2_offset %" - PRIx64 ": %s\n", l2_offset, strerror(-refcount)); - goto fail; - } - if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) { - fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64 - " refcount=%d\n", l2_offset, refcount); - res->corruptions++; - } - } - - /* Mark L2 table as used */ - l2_offset &= L1E_OFFSET_MASK; - inc_refcounts(bs, res, refcount_table, refcount_table_size, - l2_offset, s->cluster_size); - - /* L2 tables are cluster aligned */ - if (l2_offset & (s->cluster_size - 1)) { - 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: - fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n"); - res->check_errors++; - g_free(l1_table); - return -EIO; -} - -/* - * 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) -{ - BDRVQcowState *s = bs->opaque; - int64_t size, i, highest_cluster; - int nb_clusters, refcount1, refcount2; - QCowSnapshot *sn; - uint16_t *refcount_table; - int ret; - - size = bdrv_getlength(bs->file); - nb_clusters = size_to_clusters(s, size); - refcount_table = g_malloc0(nb_clusters * sizeof(uint16_t)); - - res->bfi.total_clusters = - size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE); - - /* header */ - inc_refcounts(bs, res, refcount_table, nb_clusters, - 0, s->cluster_size); - - /* current L1 table */ - ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, - s->l1_table_offset, s->l1_size, - CHECK_OFLAG_COPIED | CHECK_FRAG_INFO); - if (ret < 0) { - goto fail; - } - - /* 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) { - goto fail; - } - } - inc_refcounts(bs, res, refcount_table, nb_clusters, - s->snapshots_offset, s->snapshots_size); - - /* refcount data */ - inc_refcounts(bs, res, refcount_table, nb_clusters, - s->refcount_table_offset, - s->refcount_table_size * sizeof(uint64_t)); - - 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 & (s->cluster_size - 1)) { - fprintf(stderr, "ERROR refcount block %" PRId64 " is not " - "cluster aligned; refcount table entry corrupted\n", i); - res->corruptions++; - continue; - } - - if (cluster >= nb_clusters) { - fprintf(stderr, "ERROR refcount block %" PRId64 - " is outside image\n", i); - res->corruptions++; - continue; - } - - if (offset != 0) { - inc_refcounts(bs, res, refcount_table, nb_clusters, - offset, s->cluster_size); - if (refcount_table[cluster] != 1) { - fprintf(stderr, "ERROR refcount block %" PRId64 - " refcount=%d\n", - i, refcount_table[cluster]); - res->corruptions++; - } - } - } - - /* compare ref counts */ - for (i = 0, highest_cluster = 0; i < nb_clusters; i++) { - refcount1 = get_refcount(bs, i); - if (refcount1 < 0) { - fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n", - i, strerror(-refcount1)); - res->check_errors++; - continue; - } - - refcount2 = 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 > 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=%d reference=%d\n", - num_fixed != NULL ? "Repairing" : - refcount1 < refcount2 ? "ERROR" : - "Leaked", - i, refcount1, refcount2); - - if (num_fixed) { - ret = update_refcount(bs, i << s->cluster_bits, 1, - refcount2 - refcount1, - 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++; - } - } - } - - res->image_end_offset = (highest_cluster + 1) * s->cluster_size; - ret = 0; - -fail: - g_free(refcount_table); - - return ret; -} - |