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a1b4ecfd6f
The validity of these was double-checked with Alberto Faria's static analyzer. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20221013123711.620631-13-pbonzini@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
3742 lines
129 KiB
C
3742 lines
129 KiB
C
/*
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* Block driver for the QCOW version 2 format
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*
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* Copyright (c) 2004-2006 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "qcow2.h"
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#include "qemu/range.h"
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#include "qemu/bswap.h"
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#include "qemu/cutils.h"
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#include "qemu/memalign.h"
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#include "trace.h"
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static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size,
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uint64_t max);
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G_GNUC_WARN_UNUSED_RESULT
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static int update_refcount(BlockDriverState *bs,
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int64_t offset, int64_t length, uint64_t addend,
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bool decrease, enum qcow2_discard_type type);
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static uint64_t get_refcount_ro0(const void *refcount_array, uint64_t index);
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static uint64_t get_refcount_ro1(const void *refcount_array, uint64_t index);
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static uint64_t get_refcount_ro2(const void *refcount_array, uint64_t index);
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static uint64_t get_refcount_ro3(const void *refcount_array, uint64_t index);
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static uint64_t get_refcount_ro4(const void *refcount_array, uint64_t index);
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static uint64_t get_refcount_ro5(const void *refcount_array, uint64_t index);
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static uint64_t get_refcount_ro6(const void *refcount_array, uint64_t index);
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static void set_refcount_ro0(void *refcount_array, uint64_t index,
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uint64_t value);
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static void set_refcount_ro1(void *refcount_array, uint64_t index,
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uint64_t value);
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static void set_refcount_ro2(void *refcount_array, uint64_t index,
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uint64_t value);
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static void set_refcount_ro3(void *refcount_array, uint64_t index,
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uint64_t value);
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static void set_refcount_ro4(void *refcount_array, uint64_t index,
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uint64_t value);
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static void set_refcount_ro5(void *refcount_array, uint64_t index,
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uint64_t value);
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static void set_refcount_ro6(void *refcount_array, uint64_t index,
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uint64_t value);
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static Qcow2GetRefcountFunc *const get_refcount_funcs[] = {
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&get_refcount_ro0,
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&get_refcount_ro1,
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&get_refcount_ro2,
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&get_refcount_ro3,
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&get_refcount_ro4,
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&get_refcount_ro5,
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&get_refcount_ro6
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};
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static Qcow2SetRefcountFunc *const set_refcount_funcs[] = {
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&set_refcount_ro0,
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&set_refcount_ro1,
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&set_refcount_ro2,
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&set_refcount_ro3,
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&set_refcount_ro4,
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&set_refcount_ro5,
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&set_refcount_ro6
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};
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/*********************************************************/
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/* refcount handling */
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static void update_max_refcount_table_index(BDRVQcow2State *s)
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{
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unsigned i = s->refcount_table_size - 1;
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while (i > 0 && (s->refcount_table[i] & REFT_OFFSET_MASK) == 0) {
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i--;
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}
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/* Set s->max_refcount_table_index to the index of the last used entry */
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s->max_refcount_table_index = i;
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}
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int coroutine_fn qcow2_refcount_init(BlockDriverState *bs)
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{
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BDRVQcow2State *s = bs->opaque;
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unsigned int refcount_table_size2, i;
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int ret;
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assert(s->refcount_order >= 0 && s->refcount_order <= 6);
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s->get_refcount = get_refcount_funcs[s->refcount_order];
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s->set_refcount = set_refcount_funcs[s->refcount_order];
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assert(s->refcount_table_size <= INT_MAX / REFTABLE_ENTRY_SIZE);
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refcount_table_size2 = s->refcount_table_size * REFTABLE_ENTRY_SIZE;
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s->refcount_table = g_try_malloc(refcount_table_size2);
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if (s->refcount_table_size > 0) {
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if (s->refcount_table == NULL) {
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ret = -ENOMEM;
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goto fail;
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}
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BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_LOAD);
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ret = bdrv_pread(bs->file, s->refcount_table_offset,
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refcount_table_size2, s->refcount_table, 0);
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if (ret < 0) {
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goto fail;
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}
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for(i = 0; i < s->refcount_table_size; i++)
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be64_to_cpus(&s->refcount_table[i]);
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update_max_refcount_table_index(s);
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}
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return 0;
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fail:
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return ret;
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}
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void qcow2_refcount_close(BlockDriverState *bs)
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{
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BDRVQcow2State *s = bs->opaque;
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g_free(s->refcount_table);
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}
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static uint64_t get_refcount_ro0(const void *refcount_array, uint64_t index)
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{
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return (((const uint8_t *)refcount_array)[index / 8] >> (index % 8)) & 0x1;
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}
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static void set_refcount_ro0(void *refcount_array, uint64_t index,
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uint64_t value)
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{
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assert(!(value >> 1));
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((uint8_t *)refcount_array)[index / 8] &= ~(0x1 << (index % 8));
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((uint8_t *)refcount_array)[index / 8] |= value << (index % 8);
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}
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static uint64_t get_refcount_ro1(const void *refcount_array, uint64_t index)
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{
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return (((const uint8_t *)refcount_array)[index / 4] >> (2 * (index % 4)))
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& 0x3;
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}
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static void set_refcount_ro1(void *refcount_array, uint64_t index,
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uint64_t value)
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{
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assert(!(value >> 2));
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((uint8_t *)refcount_array)[index / 4] &= ~(0x3 << (2 * (index % 4)));
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((uint8_t *)refcount_array)[index / 4] |= value << (2 * (index % 4));
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}
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static uint64_t get_refcount_ro2(const void *refcount_array, uint64_t index)
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{
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return (((const uint8_t *)refcount_array)[index / 2] >> (4 * (index % 2)))
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& 0xf;
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}
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static void set_refcount_ro2(void *refcount_array, uint64_t index,
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uint64_t value)
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{
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assert(!(value >> 4));
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((uint8_t *)refcount_array)[index / 2] &= ~(0xf << (4 * (index % 2)));
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((uint8_t *)refcount_array)[index / 2] |= value << (4 * (index % 2));
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}
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static uint64_t get_refcount_ro3(const void *refcount_array, uint64_t index)
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{
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return ((const uint8_t *)refcount_array)[index];
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}
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static void set_refcount_ro3(void *refcount_array, uint64_t index,
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uint64_t value)
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{
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assert(!(value >> 8));
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((uint8_t *)refcount_array)[index] = value;
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}
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static uint64_t get_refcount_ro4(const void *refcount_array, uint64_t index)
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{
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return be16_to_cpu(((const uint16_t *)refcount_array)[index]);
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}
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static void set_refcount_ro4(void *refcount_array, uint64_t index,
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uint64_t value)
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{
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assert(!(value >> 16));
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((uint16_t *)refcount_array)[index] = cpu_to_be16(value);
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}
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static uint64_t get_refcount_ro5(const void *refcount_array, uint64_t index)
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{
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return be32_to_cpu(((const uint32_t *)refcount_array)[index]);
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}
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static void set_refcount_ro5(void *refcount_array, uint64_t index,
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uint64_t value)
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{
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assert(!(value >> 32));
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((uint32_t *)refcount_array)[index] = cpu_to_be32(value);
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}
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static uint64_t get_refcount_ro6(const void *refcount_array, uint64_t index)
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{
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return be64_to_cpu(((const uint64_t *)refcount_array)[index]);
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}
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static void set_refcount_ro6(void *refcount_array, uint64_t index,
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uint64_t value)
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{
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((uint64_t *)refcount_array)[index] = cpu_to_be64(value);
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}
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static int load_refcount_block(BlockDriverState *bs,
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int64_t refcount_block_offset,
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void **refcount_block)
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{
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BDRVQcow2State *s = bs->opaque;
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD);
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return qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset,
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refcount_block);
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}
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/*
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* Retrieves the refcount of the cluster given by its index and stores it in
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* *refcount. Returns 0 on success and -errno on failure.
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*/
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int qcow2_get_refcount(BlockDriverState *bs, int64_t cluster_index,
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uint64_t *refcount)
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{
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BDRVQcow2State *s = bs->opaque;
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uint64_t refcount_table_index, block_index;
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int64_t refcount_block_offset;
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int ret;
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void *refcount_block;
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refcount_table_index = cluster_index >> s->refcount_block_bits;
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if (refcount_table_index >= s->refcount_table_size) {
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*refcount = 0;
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return 0;
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}
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refcount_block_offset =
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s->refcount_table[refcount_table_index] & REFT_OFFSET_MASK;
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if (!refcount_block_offset) {
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*refcount = 0;
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return 0;
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}
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if (offset_into_cluster(s, refcount_block_offset)) {
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qcow2_signal_corruption(bs, true, -1, -1, "Refblock offset %#" PRIx64
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" unaligned (reftable index: %#" PRIx64 ")",
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refcount_block_offset, refcount_table_index);
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return -EIO;
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}
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ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset,
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&refcount_block);
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if (ret < 0) {
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return ret;
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}
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block_index = cluster_index & (s->refcount_block_size - 1);
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*refcount = s->get_refcount(refcount_block, block_index);
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qcow2_cache_put(s->refcount_block_cache, &refcount_block);
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return 0;
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}
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/* Checks if two offsets are described by the same refcount block */
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static int in_same_refcount_block(BDRVQcow2State *s, uint64_t offset_a,
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uint64_t offset_b)
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{
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uint64_t block_a = offset_a >> (s->cluster_bits + s->refcount_block_bits);
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uint64_t block_b = offset_b >> (s->cluster_bits + s->refcount_block_bits);
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return (block_a == block_b);
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}
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/*
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* Loads a refcount block. If it doesn't exist yet, it is allocated first
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* (including growing the refcount table if needed).
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*
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* Returns 0 on success or -errno in error case
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*/
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static int alloc_refcount_block(BlockDriverState *bs,
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int64_t cluster_index, void **refcount_block)
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{
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BDRVQcow2State *s = bs->opaque;
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unsigned int refcount_table_index;
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int64_t ret;
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC);
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/* Find the refcount block for the given cluster */
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refcount_table_index = cluster_index >> s->refcount_block_bits;
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if (refcount_table_index < s->refcount_table_size) {
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uint64_t refcount_block_offset =
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s->refcount_table[refcount_table_index] & REFT_OFFSET_MASK;
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/* If it's already there, we're done */
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if (refcount_block_offset) {
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if (offset_into_cluster(s, refcount_block_offset)) {
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qcow2_signal_corruption(bs, true, -1, -1, "Refblock offset %#"
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PRIx64 " unaligned (reftable index: "
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"%#x)", refcount_block_offset,
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refcount_table_index);
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return -EIO;
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}
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return load_refcount_block(bs, refcount_block_offset,
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refcount_block);
|
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}
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}
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/*
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* If we came here, we need to allocate something. Something is at least
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* a cluster for the new refcount block. It may also include a new refcount
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* table if the old refcount table is too small.
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*
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* Note that allocating clusters here needs some special care:
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*
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* - We can't use the normal qcow2_alloc_clusters(), it would try to
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* increase the refcount and very likely we would end up with an endless
|
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* recursion. Instead we must place the refcount blocks in a way that
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* they can describe them themselves.
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*
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* - We need to consider that at this point we are inside update_refcounts
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* and potentially doing an initial refcount increase. This means that
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* some clusters have already been allocated by the caller, but their
|
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* refcount isn't accurate yet. If we allocate clusters for metadata, we
|
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* need to return -EAGAIN to signal the caller that it needs to restart
|
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* the search for free clusters.
|
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*
|
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* - alloc_clusters_noref and qcow2_free_clusters may load a different
|
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* refcount block into the cache
|
|
*/
|
|
|
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*refcount_block = NULL;
|
|
|
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/* We write to the refcount table, so we might depend on L2 tables */
|
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ret = qcow2_cache_flush(bs, s->l2_table_cache);
|
|
if (ret < 0) {
|
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return ret;
|
|
}
|
|
|
|
/* Allocate the refcount block itself and mark it as used */
|
|
int64_t new_block = alloc_clusters_noref(bs, s->cluster_size, INT64_MAX);
|
|
if (new_block < 0) {
|
|
return new_block;
|
|
}
|
|
|
|
/* The offset must fit in the offset field of the refcount table entry */
|
|
assert((new_block & REFT_OFFSET_MASK) == new_block);
|
|
|
|
/* If we're allocating the block at offset 0 then something is wrong */
|
|
if (new_block == 0) {
|
|
qcow2_signal_corruption(bs, true, -1, -1, "Preventing invalid "
|
|
"allocation of refcount block at offset 0");
|
|
return -EIO;
|
|
}
|
|
|
|
#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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
ret = qcow2_cache_flush(bs, s->refcount_block_cache);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/* 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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
/* 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 * REFTABLE_ENTRY_SIZE,
|
|
sizeof(data64), &data64, 0);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
s->refcount_table[refcount_table_index] = new_block;
|
|
/* If there's a hole in s->refcount_table then it can happen
|
|
* that refcount_table_index < s->max_refcount_table_index */
|
|
s->max_refcount_table_index =
|
|
MAX(s->max_refcount_table_index, refcount_table_index);
|
|
|
|
/* 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(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);
|
|
|
|
/* Create the new refcount table and blocks */
|
|
uint64_t meta_offset = (blocks_used * s->refcount_block_size) *
|
|
s->cluster_size;
|
|
|
|
ret = qcow2_refcount_area(bs, meta_offset, 0, false,
|
|
refcount_table_index, new_block);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
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:
|
|
if (*refcount_block != NULL) {
|
|
qcow2_cache_put(s->refcount_block_cache, refcount_block);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Starting at @start_offset, this function creates new self-covering refcount
|
|
* structures: A new refcount table and refcount blocks which cover all of
|
|
* themselves, and a number of @additional_clusters beyond their end.
|
|
* @start_offset must be at the end of the image file, that is, there must be
|
|
* only empty space beyond it.
|
|
* If @exact_size is false, the refcount table will have 50 % more entries than
|
|
* necessary so it will not need to grow again soon.
|
|
* If @new_refblock_offset is not zero, it contains the offset of a refcount
|
|
* block that should be entered into the new refcount table at index
|
|
* @new_refblock_index.
|
|
*
|
|
* Returns: The offset after the new refcount structures (i.e. where the
|
|
* @additional_clusters may be placed) on success, -errno on error.
|
|
*/
|
|
int64_t qcow2_refcount_area(BlockDriverState *bs, uint64_t start_offset,
|
|
uint64_t additional_clusters, bool exact_size,
|
|
int new_refblock_index,
|
|
uint64_t new_refblock_offset)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
uint64_t total_refblock_count_u64, additional_refblock_count;
|
|
int total_refblock_count, table_size, area_reftable_index, table_clusters;
|
|
int i;
|
|
uint64_t table_offset, block_offset, end_offset;
|
|
int ret;
|
|
uint64_t *new_table;
|
|
|
|
assert(!(start_offset % s->cluster_size));
|
|
|
|
qcow2_refcount_metadata_size(start_offset / s->cluster_size +
|
|
additional_clusters,
|
|
s->cluster_size, s->refcount_order,
|
|
!exact_size, &total_refblock_count_u64);
|
|
if (total_refblock_count_u64 > QCOW_MAX_REFTABLE_SIZE) {
|
|
return -EFBIG;
|
|
}
|
|
total_refblock_count = total_refblock_count_u64;
|
|
|
|
/* Index in the refcount table of the first refcount block to cover the area
|
|
* of refcount structures we are about to create; we know that
|
|
* @total_refblock_count can cover @start_offset, so this will definitely
|
|
* fit into an int. */
|
|
area_reftable_index = (start_offset / s->cluster_size) /
|
|
s->refcount_block_size;
|
|
|
|
if (exact_size) {
|
|
table_size = total_refblock_count;
|
|
} else {
|
|
table_size = total_refblock_count +
|
|
DIV_ROUND_UP(total_refblock_count, 2);
|
|
}
|
|
/* The qcow2 file can only store the reftable size in number of clusters */
|
|
table_size = ROUND_UP(table_size, s->cluster_size / REFTABLE_ENTRY_SIZE);
|
|
table_clusters = (table_size * REFTABLE_ENTRY_SIZE) / s->cluster_size;
|
|
|
|
if (table_size > QCOW_MAX_REFTABLE_SIZE) {
|
|
return -EFBIG;
|
|
}
|
|
|
|
new_table = g_try_new0(uint64_t, table_size);
|
|
|
|
assert(table_size > 0);
|
|
if (new_table == NULL) {
|
|
ret = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
|
|
/* Fill the new refcount table */
|
|
if (table_size > s->max_refcount_table_index) {
|
|
/* We're actually growing the reftable */
|
|
memcpy(new_table, s->refcount_table,
|
|
(s->max_refcount_table_index + 1) * REFTABLE_ENTRY_SIZE);
|
|
} else {
|
|
/* Improbable case: We're shrinking the reftable. However, the caller
|
|
* has assured us that there is only empty space beyond @start_offset,
|
|
* so we can simply drop all of the refblocks that won't fit into the
|
|
* new reftable. */
|
|
memcpy(new_table, s->refcount_table, table_size * REFTABLE_ENTRY_SIZE);
|
|
}
|
|
|
|
if (new_refblock_offset) {
|
|
assert(new_refblock_index < total_refblock_count);
|
|
new_table[new_refblock_index] = new_refblock_offset;
|
|
}
|
|
|
|
/* Count how many new refblocks we have to create */
|
|
additional_refblock_count = 0;
|
|
for (i = area_reftable_index; i < total_refblock_count; i++) {
|
|
if (!new_table[i]) {
|
|
additional_refblock_count++;
|
|
}
|
|
}
|
|
|
|
table_offset = start_offset + additional_refblock_count * s->cluster_size;
|
|
end_offset = table_offset + table_clusters * s->cluster_size;
|
|
|
|
/* Fill the refcount blocks, and create new ones, if necessary */
|
|
block_offset = start_offset;
|
|
for (i = area_reftable_index; i < total_refblock_count; i++) {
|
|
void *refblock_data;
|
|
uint64_t first_offset_covered;
|
|
|
|
/* Reuse an existing refblock if possible, create a new one otherwise */
|
|
if (new_table[i]) {
|
|
ret = qcow2_cache_get(bs, s->refcount_block_cache, new_table[i],
|
|
&refblock_data);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
} else {
|
|
ret = qcow2_cache_get_empty(bs, s->refcount_block_cache,
|
|
block_offset, &refblock_data);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
memset(refblock_data, 0, s->cluster_size);
|
|
qcow2_cache_entry_mark_dirty(s->refcount_block_cache,
|
|
refblock_data);
|
|
|
|
new_table[i] = block_offset;
|
|
block_offset += s->cluster_size;
|
|
}
|
|
|
|
/* First host offset covered by this refblock */
|
|
first_offset_covered = (uint64_t)i * s->refcount_block_size *
|
|
s->cluster_size;
|
|
if (first_offset_covered < end_offset) {
|
|
int j, end_index;
|
|
|
|
/* Set the refcount of all of the new refcount structures to 1 */
|
|
|
|
if (first_offset_covered < start_offset) {
|
|
assert(i == area_reftable_index);
|
|
j = (start_offset - first_offset_covered) / s->cluster_size;
|
|
assert(j < s->refcount_block_size);
|
|
} else {
|
|
j = 0;
|
|
}
|
|
|
|
end_index = MIN((end_offset - first_offset_covered) /
|
|
s->cluster_size,
|
|
s->refcount_block_size);
|
|
|
|
for (; j < end_index; j++) {
|
|
/* The caller guaranteed us this space would be empty */
|
|
assert(s->get_refcount(refblock_data, j) == 0);
|
|
s->set_refcount(refblock_data, j, 1);
|
|
}
|
|
|
|
qcow2_cache_entry_mark_dirty(s->refcount_block_cache,
|
|
refblock_data);
|
|
}
|
|
|
|
qcow2_cache_put(s->refcount_block_cache, &refblock_data);
|
|
}
|
|
|
|
assert(block_offset == table_offset);
|
|
|
|
/* Write refcount blocks to disk */
|
|
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS);
|
|
ret = qcow2_cache_flush(bs, s->refcount_block_cache);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/* Write refcount table to disk */
|
|
for (i = 0; i < total_refblock_count; i++) {
|
|
cpu_to_be64s(&new_table[i]);
|
|
}
|
|
|
|
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE);
|
|
ret = bdrv_pwrite_sync(bs->file, table_offset,
|
|
table_size * REFTABLE_ENTRY_SIZE, new_table, 0);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
for (i = 0; i < total_refblock_count; 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;
|
|
data.d64 = cpu_to_be64(table_offset);
|
|
data.d32 = cpu_to_be32(table_clusters);
|
|
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE);
|
|
ret = bdrv_pwrite_sync(bs->file,
|
|
offsetof(QCowHeader, refcount_table_offset),
|
|
sizeof(data), &data, 0);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/* 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;
|
|
update_max_refcount_table_index(s);
|
|
|
|
/* Free old table. */
|
|
qcow2_free_clusters(bs, old_table_offset,
|
|
old_table_size * REFTABLE_ENTRY_SIZE,
|
|
QCOW2_DISCARD_OTHER);
|
|
|
|
return end_offset;
|
|
|
|
fail:
|
|
g_free(new_table);
|
|
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) {
|
|
int r2 = bdrv_pdiscard(bs->file, d->offset, d->bytes);
|
|
if (r2 < 0) {
|
|
trace_qcow2_process_discards_failed_region(d->offset, d->bytes,
|
|
r2);
|
|
}
|
|
}
|
|
|
|
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 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(s->refcount_block_cache, &refcount_block);
|
|
}
|
|
ret = alloc_refcount_block(bs, cluster_index, &refcount_block);
|
|
/* If the caller needs to restart the search for free clusters,
|
|
* try the same ones first to see if they're still free. */
|
|
if (ret == -EAGAIN) {
|
|
if (s->free_cluster_index > (start >> s->cluster_bits)) {
|
|
s->free_cluster_index = (start >> s->cluster_bits);
|
|
}
|
|
}
|
|
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 & (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) {
|
|
void *table;
|
|
|
|
table = qcow2_cache_is_table_offset(s->refcount_block_cache,
|
|
offset);
|
|
if (table != NULL) {
|
|
qcow2_cache_put(s->refcount_block_cache, &refcount_block);
|
|
old_table_index = -1;
|
|
qcow2_cache_discard(s->refcount_block_cache, table);
|
|
}
|
|
|
|
table = qcow2_cache_is_table_offset(s->l2_table_cache, offset);
|
|
if (table != NULL) {
|
|
qcow2_cache_discard(s->l2_table_cache, table);
|
|
}
|
|
|
|
if (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(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,
|
|
uint64_t max)
|
|
{
|
|
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 the requested max */
|
|
if (s->free_cluster_index > 0 &&
|
|
s->free_cluster_index - 1 > (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, QCOW_MAX_CLUSTER_OFFSET);
|
|
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;
|
|
|
|
new_cluster = alloc_clusters_noref(bs, s->cluster_size,
|
|
MIN(s->cluster_offset_mask,
|
|
QCOW_MAX_CLUSTER_OFFSET));
|
|
if (new_cluster < 0) {
|
|
return new_cluster;
|
|
}
|
|
|
|
if (new_cluster == 0) {
|
|
qcow2_signal_corruption(bs, true, -1, -1, "Preventing invalid "
|
|
"allocation of compressed cluster "
|
|
"at offset 0");
|
|
return -EIO;
|
|
}
|
|
|
|
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_cluster(BlockDriverState *bs, uint64_t l2_entry,
|
|
enum qcow2_discard_type type)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QCow2ClusterType ctype = qcow2_get_cluster_type(bs, l2_entry);
|
|
|
|
if (has_data_file(bs)) {
|
|
if (s->discard_passthrough[type] &&
|
|
(ctype == QCOW2_CLUSTER_NORMAL ||
|
|
ctype == QCOW2_CLUSTER_ZERO_ALLOC))
|
|
{
|
|
bdrv_pdiscard(s->data_file, l2_entry & L2E_OFFSET_MASK,
|
|
s->cluster_size);
|
|
}
|
|
return;
|
|
}
|
|
|
|
switch (ctype) {
|
|
case QCOW2_CLUSTER_COMPRESSED:
|
|
{
|
|
uint64_t coffset;
|
|
int csize;
|
|
|
|
qcow2_parse_compressed_l2_entry(bs, l2_entry, &coffset, &csize);
|
|
qcow2_free_clusters(bs, coffset, csize, type);
|
|
}
|
|
break;
|
|
case QCOW2_CLUSTER_NORMAL:
|
|
case QCOW2_CLUSTER_ZERO_ALLOC:
|
|
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,
|
|
s->cluster_size, type);
|
|
}
|
|
break;
|
|
case QCOW2_CLUSTER_ZERO_PLAIN:
|
|
case QCOW2_CLUSTER_UNALLOCATED:
|
|
break;
|
|
default:
|
|
abort();
|
|
}
|
|
}
|
|
|
|
int qcow2_write_caches(BlockDriverState *bs)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
int ret;
|
|
|
|
ret = qcow2_cache_write(bs, s->l2_table_cache);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
if (qcow2_need_accurate_refcounts(s)) {
|
|
ret = qcow2_cache_write(bs, s->refcount_block_cache);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int qcow2_flush_caches(BlockDriverState *bs)
|
|
{
|
|
int ret = qcow2_write_caches(bs);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
return bdrv_flush(bs->file->bs);
|
|
}
|
|
|
|
/*********************************************************/
|
|
/* 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_slice, l2_offset, entry, l1_size2, refcount;
|
|
bool l1_allocated = false;
|
|
int64_t old_entry, old_l2_offset;
|
|
unsigned slice, slice_size2, n_slices;
|
|
int i, j, l1_modified = 0;
|
|
int ret;
|
|
|
|
assert(addend >= -1 && addend <= 1);
|
|
|
|
l2_slice = NULL;
|
|
l1_table = NULL;
|
|
l1_size2 = l1_size * L1E_SIZE;
|
|
slice_size2 = s->l2_slice_size * l2_entry_size(s);
|
|
n_slices = s->cluster_size / slice_size2;
|
|
|
|
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(l1_size2);
|
|
if (l1_size2 && l1_table == NULL) {
|
|
ret = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
l1_allocated = true;
|
|
|
|
ret = bdrv_pread(bs->file, l1_table_offset, l1_size2, l1_table, 0);
|
|
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;
|
|
}
|
|
|
|
for (slice = 0; slice < n_slices; slice++) {
|
|
ret = qcow2_cache_get(bs, s->l2_table_cache,
|
|
l2_offset + slice * slice_size2,
|
|
(void **) &l2_slice);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
for (j = 0; j < s->l2_slice_size; j++) {
|
|
uint64_t cluster_index;
|
|
uint64_t offset;
|
|
|
|
entry = get_l2_entry(s, l2_slice, j);
|
|
old_entry = entry;
|
|
entry &= ~QCOW_OFLAG_COPIED;
|
|
offset = entry & L2E_OFFSET_MASK;
|
|
|
|
switch (qcow2_get_cluster_type(bs, entry)) {
|
|
case QCOW2_CLUSTER_COMPRESSED:
|
|
if (addend != 0) {
|
|
uint64_t coffset;
|
|
int csize;
|
|
|
|
qcow2_parse_compressed_l2_entry(bs, entry,
|
|
&coffset, &csize);
|
|
ret = update_refcount(
|
|
bs, coffset, csize,
|
|
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_ALLOC:
|
|
if (offset_into_cluster(s, offset)) {
|
|
/* Here l2_index means table (not slice) index */
|
|
int l2_index = slice * s->l2_slice_size + j;
|
|
qcow2_signal_corruption(
|
|
bs, true, -1, -1, "Cluster "
|
|
"allocation offset %#" PRIx64
|
|
" unaligned (L2 offset: %#"
|
|
PRIx64 ", L2 index: %#x)",
|
|
offset, l2_offset, l2_index);
|
|
ret = -EIO;
|
|
goto fail;
|
|
}
|
|
|
|
cluster_index = offset >> s->cluster_bits;
|
|
assert(cluster_index);
|
|
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_ZERO_PLAIN:
|
|
case QCOW2_CLUSTER_UNALLOCATED:
|
|
refcount = 0;
|
|
break;
|
|
|
|
default:
|
|
abort();
|
|
}
|
|
|
|
if (refcount == 1) {
|
|
entry |= QCOW_OFLAG_COPIED;
|
|
}
|
|
if (entry != old_entry) {
|
|
if (addend > 0) {
|
|
qcow2_cache_set_dependency(bs, s->l2_table_cache,
|
|
s->refcount_block_cache);
|
|
}
|
|
set_l2_entry(s, l2_slice, j, entry);
|
|
qcow2_cache_entry_mark_dirty(s->l2_table_cache,
|
|
l2_slice);
|
|
}
|
|
}
|
|
|
|
qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
|
|
}
|
|
|
|
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_slice) {
|
|
qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
|
|
}
|
|
|
|
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_size2, l1_table,
|
|
0);
|
|
|
|
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.
|
|
*/
|
|
int qcow2_inc_refcounts_imrt(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;
|
|
int64_t file_len;
|
|
int ret;
|
|
|
|
if (size <= 0) {
|
|
return 0;
|
|
}
|
|
|
|
file_len = bdrv_getlength(bs->file->bs);
|
|
if (file_len < 0) {
|
|
return file_len;
|
|
}
|
|
|
|
/*
|
|
* Last cluster of qcow2 image may be semi-allocated, so it may be OK to
|
|
* reference some space after file end but it should be less than one
|
|
* cluster.
|
|
*/
|
|
if (offset + size - file_len >= s->cluster_size) {
|
|
fprintf(stderr, "ERROR: counting reference for region exceeding the "
|
|
"end of the file by one cluster or more: offset 0x%" PRIx64
|
|
" size 0x%" PRIx64 "\n", offset, size);
|
|
res->corruptions++;
|
|
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 */
|
|
};
|
|
|
|
/*
|
|
* Fix L2 entry by making it QCOW2_CLUSTER_ZERO_PLAIN (or making all its present
|
|
* subclusters QCOW2_SUBCLUSTER_ZERO_PLAIN).
|
|
*
|
|
* This function decrements res->corruptions on success, so the caller is
|
|
* responsible to increment res->corruptions prior to the call.
|
|
*
|
|
* On failure in-memory @l2_table may be modified.
|
|
*/
|
|
static int fix_l2_entry_by_zero(BlockDriverState *bs, BdrvCheckResult *res,
|
|
uint64_t l2_offset,
|
|
uint64_t *l2_table, int l2_index, bool active,
|
|
bool *metadata_overlap)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
int ret;
|
|
int idx = l2_index * (l2_entry_size(s) / sizeof(uint64_t));
|
|
uint64_t l2e_offset = l2_offset + (uint64_t)l2_index * l2_entry_size(s);
|
|
int ign = active ? QCOW2_OL_ACTIVE_L2 : QCOW2_OL_INACTIVE_L2;
|
|
|
|
if (has_subclusters(s)) {
|
|
uint64_t l2_bitmap = get_l2_bitmap(s, l2_table, l2_index);
|
|
|
|
/* Allocated subclusters become zero */
|
|
l2_bitmap |= l2_bitmap << 32;
|
|
l2_bitmap &= QCOW_L2_BITMAP_ALL_ZEROES;
|
|
|
|
set_l2_bitmap(s, l2_table, l2_index, l2_bitmap);
|
|
set_l2_entry(s, l2_table, l2_index, 0);
|
|
} else {
|
|
set_l2_entry(s, l2_table, l2_index, QCOW_OFLAG_ZERO);
|
|
}
|
|
|
|
ret = qcow2_pre_write_overlap_check(bs, ign, l2e_offset, l2_entry_size(s),
|
|
false);
|
|
if (metadata_overlap) {
|
|
*metadata_overlap = ret < 0;
|
|
}
|
|
if (ret < 0) {
|
|
fprintf(stderr, "ERROR: Overlap check failed\n");
|
|
goto fail;
|
|
}
|
|
|
|
ret = bdrv_pwrite_sync(bs->file, l2e_offset, l2_entry_size(s),
|
|
&l2_table[idx], 0);
|
|
if (ret < 0) {
|
|
fprintf(stderr, "ERROR: Failed to overwrite L2 "
|
|
"table entry: %s\n", strerror(-ret));
|
|
goto fail;
|
|
}
|
|
|
|
res->corruptions--;
|
|
res->corruptions_fixed++;
|
|
return 0;
|
|
|
|
fail:
|
|
res->check_errors++;
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* 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, BdrvCheckMode fix, bool active)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
uint64_t l2_entry, l2_bitmap;
|
|
uint64_t next_contiguous_offset = 0;
|
|
int i, ret;
|
|
size_t l2_size_bytes = s->l2_size * l2_entry_size(s);
|
|
g_autofree uint64_t *l2_table = g_malloc(l2_size_bytes);
|
|
bool metadata_overlap;
|
|
|
|
/* Read L2 table from disk */
|
|
ret = bdrv_pread(bs->file, l2_offset, l2_size_bytes, l2_table, 0);
|
|
if (ret < 0) {
|
|
fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n");
|
|
res->check_errors++;
|
|
return ret;
|
|
}
|
|
|
|
/* Do the actual checks */
|
|
for (i = 0; i < s->l2_size; i++) {
|
|
uint64_t coffset;
|
|
int csize;
|
|
QCow2ClusterType type;
|
|
|
|
l2_entry = get_l2_entry(s, l2_table, i);
|
|
l2_bitmap = get_l2_bitmap(s, l2_table, i);
|
|
type = qcow2_get_cluster_type(bs, l2_entry);
|
|
|
|
if (type != QCOW2_CLUSTER_COMPRESSED) {
|
|
/* Check reserved bits of Standard Cluster Descriptor */
|
|
if (l2_entry & L2E_STD_RESERVED_MASK) {
|
|
fprintf(stderr, "ERROR found l2 entry with reserved bits set: "
|
|
"%" PRIx64 "\n", l2_entry);
|
|
res->corruptions++;
|
|
}
|
|
}
|
|
|
|
switch (type) {
|
|
case QCOW2_CLUSTER_COMPRESSED:
|
|
/* Compressed clusters don't have QCOW_OFLAG_COPIED */
|
|
if (l2_entry & QCOW_OFLAG_COPIED) {
|
|
fprintf(stderr, "ERROR: coffset=0x%" PRIx64 ": "
|
|
"copied flag must never be set for compressed "
|
|
"clusters\n", l2_entry & s->cluster_offset_mask);
|
|
l2_entry &= ~QCOW_OFLAG_COPIED;
|
|
res->corruptions++;
|
|
}
|
|
|
|
if (has_data_file(bs)) {
|
|
fprintf(stderr, "ERROR compressed cluster %d with data file, "
|
|
"entry=0x%" PRIx64 "\n", i, l2_entry);
|
|
res->corruptions++;
|
|
break;
|
|
}
|
|
|
|
if (l2_bitmap) {
|
|
fprintf(stderr, "ERROR compressed cluster %d with non-zero "
|
|
"subcluster allocation bitmap, entry=0x%" PRIx64 "\n",
|
|
i, l2_entry);
|
|
res->corruptions++;
|
|
break;
|
|
}
|
|
|
|
/* Mark cluster as used */
|
|
qcow2_parse_compressed_l2_entry(bs, l2_entry, &coffset, &csize);
|
|
ret = qcow2_inc_refcounts_imrt(
|
|
bs, res, refcount_table, refcount_table_size, coffset, csize);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
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_ALLOC:
|
|
case QCOW2_CLUSTER_NORMAL:
|
|
{
|
|
uint64_t offset = l2_entry & L2E_OFFSET_MASK;
|
|
|
|
if ((l2_bitmap >> 32) & l2_bitmap) {
|
|
res->corruptions++;
|
|
fprintf(stderr, "ERROR offset=%" PRIx64 ": Allocated "
|
|
"cluster has corrupted subcluster allocation bitmap\n",
|
|
offset);
|
|
}
|
|
|
|
/* Correct offsets are cluster aligned */
|
|
if (offset_into_cluster(s, offset)) {
|
|
bool contains_data;
|
|
res->corruptions++;
|
|
|
|
if (has_subclusters(s)) {
|
|
contains_data = (l2_bitmap & QCOW_L2_BITMAP_ALL_ALLOC);
|
|
} else {
|
|
contains_data = !(l2_entry & QCOW_OFLAG_ZERO);
|
|
}
|
|
|
|
if (!contains_data) {
|
|
fprintf(stderr, "%s offset=%" PRIx64 ": Preallocated "
|
|
"cluster is not properly aligned; L2 entry "
|
|
"corrupted.\n",
|
|
fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR",
|
|
offset);
|
|
if (fix & BDRV_FIX_ERRORS) {
|
|
ret = fix_l2_entry_by_zero(bs, res, l2_offset,
|
|
l2_table, i, active,
|
|
&metadata_overlap);
|
|
if (metadata_overlap) {
|
|
/*
|
|
* Something is seriously wrong, so abort checking
|
|
* this L2 table.
|
|
*/
|
|
return ret;
|
|
}
|
|
|
|
if (ret == 0) {
|
|
/*
|
|
* Skip marking the cluster as used
|
|
* (it is unused now).
|
|
*/
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Failed to fix.
|
|
* Do not abort, continue checking the rest of this
|
|
* L2 table's entries.
|
|
*/
|
|
}
|
|
} else {
|
|
fprintf(stderr, "ERROR offset=%" PRIx64 ": Data cluster is "
|
|
"not properly aligned; L2 entry corrupted.\n", offset);
|
|
}
|
|
}
|
|
|
|
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 */
|
|
if (!has_data_file(bs)) {
|
|
ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table,
|
|
refcount_table_size,
|
|
offset, s->cluster_size);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
case QCOW2_CLUSTER_ZERO_PLAIN:
|
|
/* Impossible when image has subclusters */
|
|
assert(!l2_bitmap);
|
|
break;
|
|
|
|
case QCOW2_CLUSTER_UNALLOCATED:
|
|
if (l2_bitmap & QCOW_L2_BITMAP_ALL_ALLOC) {
|
|
res->corruptions++;
|
|
fprintf(stderr, "ERROR: Unallocated "
|
|
"cluster has non-zero subcluster allocation map\n");
|
|
}
|
|
break;
|
|
|
|
default:
|
|
abort();
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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, BdrvCheckMode fix, bool active)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
size_t l1_size_bytes = l1_size * L1E_SIZE;
|
|
g_autofree uint64_t *l1_table = NULL;
|
|
uint64_t l2_offset;
|
|
int i, ret;
|
|
|
|
if (!l1_size) {
|
|
return 0;
|
|
}
|
|
|
|
/* Mark L1 table as used */
|
|
ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, refcount_table_size,
|
|
l1_table_offset, l1_size_bytes);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
l1_table = g_try_malloc(l1_size_bytes);
|
|
if (l1_table == NULL) {
|
|
res->check_errors++;
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* Read L1 table entries from disk */
|
|
ret = bdrv_pread(bs->file, l1_table_offset, l1_size_bytes, l1_table, 0);
|
|
if (ret < 0) {
|
|
fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
|
|
res->check_errors++;
|
|
return ret;
|
|
}
|
|
|
|
for (i = 0; i < l1_size; i++) {
|
|
be64_to_cpus(&l1_table[i]);
|
|
}
|
|
|
|
/* Do the actual checks */
|
|
for (i = 0; i < l1_size; i++) {
|
|
if (!l1_table[i]) {
|
|
continue;
|
|
}
|
|
|
|
if (l1_table[i] & L1E_RESERVED_MASK) {
|
|
fprintf(stderr, "ERROR found L1 entry with reserved bits set: "
|
|
"%" PRIx64 "\n", l1_table[i]);
|
|
res->corruptions++;
|
|
}
|
|
|
|
l2_offset = l1_table[i] & L1E_OFFSET_MASK;
|
|
|
|
/* Mark L2 table as used */
|
|
ret = qcow2_inc_refcounts_imrt(bs, res,
|
|
refcount_table, refcount_table_size,
|
|
l2_offset, s->cluster_size);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
/* 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,
|
|
fix, active);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
bool repair;
|
|
|
|
if (fix & BDRV_FIX_ERRORS) {
|
|
/* Always repair */
|
|
repair = true;
|
|
} else if (fix & BDRV_FIX_LEAKS) {
|
|
/* Repair only if that seems safe: This function is always
|
|
* called after the refcounts have been fixed, so the refcount
|
|
* is accurate if that repair was successful */
|
|
repair = !res->check_errors && !res->corruptions && !res->leaks;
|
|
} else {
|
|
repair = false;
|
|
}
|
|
|
|
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;
|
|
int l2_dirty = 0;
|
|
|
|
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)) {
|
|
res->corruptions++;
|
|
fprintf(stderr, "%s OFLAG_COPIED L2 cluster: l1_index=%d "
|
|
"l1_entry=%" PRIx64 " refcount=%" PRIu64 "\n",
|
|
repair ? "Repairing" : "ERROR", i, l1_entry, refcount);
|
|
if (repair) {
|
|
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--;
|
|
res->corruptions_fixed++;
|
|
}
|
|
}
|
|
|
|
ret = bdrv_pread(bs->file, l2_offset, s->l2_size * l2_entry_size(s),
|
|
l2_table, 0);
|
|
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 = get_l2_entry(s, l2_table, j);
|
|
uint64_t data_offset = l2_entry & L2E_OFFSET_MASK;
|
|
QCow2ClusterType cluster_type = qcow2_get_cluster_type(bs, l2_entry);
|
|
|
|
if (cluster_type == QCOW2_CLUSTER_NORMAL ||
|
|
cluster_type == QCOW2_CLUSTER_ZERO_ALLOC) {
|
|
if (has_data_file(bs)) {
|
|
refcount = 1;
|
|
} else {
|
|
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)) {
|
|
res->corruptions++;
|
|
fprintf(stderr, "%s OFLAG_COPIED data cluster: "
|
|
"l2_entry=%" PRIx64 " refcount=%" PRIu64 "\n",
|
|
repair ? "Repairing" : "ERROR", l2_entry, refcount);
|
|
if (repair) {
|
|
set_l2_entry(s, l2_table, j,
|
|
refcount == 1 ?
|
|
l2_entry | QCOW_OFLAG_COPIED :
|
|
l2_entry & ~QCOW_OFLAG_COPIED);
|
|
l2_dirty++;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (l2_dirty > 0) {
|
|
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L2,
|
|
l2_offset, s->cluster_size,
|
|
false);
|
|
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, l2_offset, s->cluster_size, l2_table,
|
|
0);
|
|
if (ret < 0) {
|
|
fprintf(stderr, "ERROR: Could not write L2 table: %s\n",
|
|
strerror(-ret));
|
|
res->check_errors++;
|
|
goto fail;
|
|
}
|
|
res->corruptions -= l2_dirty;
|
|
res->corruptions_fixed += l2_dirty;
|
|
}
|
|
}
|
|
|
|
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] & REFT_OFFSET_MASK;
|
|
cluster = offset >> s->cluster_bits;
|
|
|
|
if (s->refcount_table[i] & REFT_RESERVED_MASK) {
|
|
fprintf(stderr, "ERROR refcount table entry %" PRId64 " has "
|
|
"reserved bits set\n", i);
|
|
res->corruptions++;
|
|
*rebuild = true;
|
|
continue;
|
|
}
|
|
|
|
/* 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) {
|
|
res->corruptions++;
|
|
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;
|
|
Error *local_err = NULL;
|
|
|
|
if (offset > INT64_MAX - s->cluster_size) {
|
|
ret = -EINVAL;
|
|
goto resize_fail;
|
|
}
|
|
|
|
ret = bdrv_truncate(bs->file, offset + s->cluster_size, false,
|
|
PREALLOC_MODE_OFF, 0, &local_err);
|
|
if (ret < 0) {
|
|
error_report_err(local_err);
|
|
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--;
|
|
res->corruptions_fixed++;
|
|
ret = qcow2_inc_refcounts_imrt(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 qcow2_inc_refcounts_imrt() */
|
|
continue;
|
|
|
|
resize_fail:
|
|
*rebuild = true;
|
|
fprintf(stderr, "ERROR could not resize image: %s\n",
|
|
strerror(-ret));
|
|
}
|
|
continue;
|
|
}
|
|
|
|
if (offset != 0) {
|
|
ret = qcow2_inc_refcounts_imrt(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 = qcow2_inc_refcounts_imrt(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,
|
|
fix, true);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
/* snapshots */
|
|
if (has_data_file(bs) && s->nb_snapshots) {
|
|
fprintf(stderr, "ERROR %d snapshots in image with data file\n",
|
|
s->nb_snapshots);
|
|
res->corruptions++;
|
|
}
|
|
|
|
for (i = 0; i < s->nb_snapshots; i++) {
|
|
sn = s->snapshots + i;
|
|
if (offset_into_cluster(s, sn->l1_table_offset)) {
|
|
fprintf(stderr, "ERROR snapshot %s (%s) l1_offset=%#" PRIx64 ": "
|
|
"L1 table is not cluster aligned; snapshot table entry "
|
|
"corrupted\n", sn->id_str, sn->name, sn->l1_table_offset);
|
|
res->corruptions++;
|
|
continue;
|
|
}
|
|
if (sn->l1_size > QCOW_MAX_L1_SIZE / L1E_SIZE) {
|
|
fprintf(stderr, "ERROR snapshot %s (%s) l1_size=%#" PRIx32 ": "
|
|
"L1 table is too large; snapshot table entry corrupted\n",
|
|
sn->id_str, sn->name, sn->l1_size);
|
|
res->corruptions++;
|
|
continue;
|
|
}
|
|
ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,
|
|
sn->l1_table_offset, sn->l1_size, 0, fix,
|
|
false);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
}
|
|
ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, nb_clusters,
|
|
s->snapshots_offset, s->snapshots_size);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
/* refcount data */
|
|
ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, nb_clusters,
|
|
s->refcount_table_offset,
|
|
s->refcount_table_size *
|
|
REFTABLE_ENTRY_SIZE);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
/* encryption */
|
|
if (s->crypto_header.length) {
|
|
ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, nb_clusters,
|
|
s->crypto_header.offset,
|
|
s->crypto_header.length);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
/* bitmaps */
|
|
ret = qcow2_check_bitmaps_refcounts(bs, res, refcount_table, nb_clusters);
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* Helper function for rebuild_refcount_structure().
|
|
*
|
|
* Scan the range of clusters [first_cluster, end_cluster) for allocated
|
|
* clusters and write all corresponding refblocks to disk. The refblock
|
|
* and allocation data is taken from the in-memory refcount table
|
|
* *refcount_table[] (of size *nb_clusters), which is basically one big
|
|
* (unlimited size) refblock for the whole image.
|
|
*
|
|
* For these refblocks, clusters are allocated using said in-memory
|
|
* refcount table. Care is taken that these allocations are reflected
|
|
* in the refblocks written to disk.
|
|
*
|
|
* The refblocks' offsets are written into a reftable, which is
|
|
* *on_disk_reftable_ptr[] (of size *on_disk_reftable_entries_ptr). If
|
|
* that reftable is of insufficient size, it will be resized to fit.
|
|
* This reftable is not written to disk.
|
|
*
|
|
* (If *on_disk_reftable_ptr is not NULL, the entries within are assumed
|
|
* to point to existing valid refblocks that do not need to be allocated
|
|
* again.)
|
|
*
|
|
* Return whether the on-disk reftable array was resized (true/false),
|
|
* or -errno on error.
|
|
*/
|
|
static int rebuild_refcounts_write_refblocks(
|
|
BlockDriverState *bs, void **refcount_table, int64_t *nb_clusters,
|
|
int64_t first_cluster, int64_t end_cluster,
|
|
uint64_t **on_disk_reftable_ptr, uint32_t *on_disk_reftable_entries_ptr,
|
|
Error **errp
|
|
)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
int64_t cluster;
|
|
int64_t refblock_offset, refblock_start, refblock_index;
|
|
int64_t first_free_cluster = 0;
|
|
uint64_t *on_disk_reftable = *on_disk_reftable_ptr;
|
|
uint32_t on_disk_reftable_entries = *on_disk_reftable_entries_ptr;
|
|
void *on_disk_refblock;
|
|
bool reftable_grown = false;
|
|
int ret;
|
|
|
|
for (cluster = first_cluster; cluster < end_cluster; cluster++) {
|
|
/* Check all clusters to find refblocks that contain non-zero entries */
|
|
if (!s->get_refcount(*refcount_table, cluster)) {
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* This cluster is allocated, so we need to create a refblock
|
|
* for it. The data we will write to disk is just the
|
|
* respective slice from *refcount_table, so it will contain
|
|
* accurate refcounts for all clusters belonging to this
|
|
* refblock. After we have written it, we will therefore skip
|
|
* all remaining clusters in this refblock.
|
|
*/
|
|
|
|
refblock_index = cluster >> s->refcount_block_bits;
|
|
refblock_start = refblock_index << s->refcount_block_bits;
|
|
|
|
if (on_disk_reftable_entries > refblock_index &&
|
|
on_disk_reftable[refblock_index])
|
|
{
|
|
/*
|
|
* We can get here after a `goto write_refblocks`: We have a
|
|
* reftable from a previous run, and the refblock is already
|
|
* allocated. No need to allocate it again.
|
|
*/
|
|
refblock_offset = on_disk_reftable[refblock_index];
|
|
} else {
|
|
int64_t refblock_cluster_index;
|
|
|
|
/* 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) {
|
|
error_setg_errno(errp, -refblock_offset,
|
|
"ERROR allocating refblock");
|
|
return refblock_offset;
|
|
}
|
|
|
|
refblock_cluster_index = refblock_offset / s->cluster_size;
|
|
if (refblock_cluster_index >= end_cluster) {
|
|
/*
|
|
* We must write the refblock that holds this refblock's
|
|
* refcount
|
|
*/
|
|
end_cluster = refblock_cluster_index + 1;
|
|
}
|
|
|
|
if (on_disk_reftable_entries <= refblock_index) {
|
|
on_disk_reftable_entries =
|
|
ROUND_UP((refblock_index + 1) * REFTABLE_ENTRY_SIZE,
|
|
s->cluster_size) / REFTABLE_ENTRY_SIZE;
|
|
on_disk_reftable =
|
|
g_try_realloc(on_disk_reftable,
|
|
on_disk_reftable_entries *
|
|
REFTABLE_ENTRY_SIZE);
|
|
if (!on_disk_reftable) {
|
|
error_setg(errp, "ERROR allocating reftable memory");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
memset(on_disk_reftable + *on_disk_reftable_entries_ptr, 0,
|
|
(on_disk_reftable_entries -
|
|
*on_disk_reftable_entries_ptr) *
|
|
REFTABLE_ENTRY_SIZE);
|
|
|
|
*on_disk_reftable_ptr = on_disk_reftable;
|
|
*on_disk_reftable_entries_ptr = on_disk_reftable_entries;
|
|
|
|
reftable_grown = true;
|
|
} else {
|
|
assert(on_disk_reftable);
|
|
}
|
|
on_disk_reftable[refblock_index] = refblock_offset;
|
|
}
|
|
|
|
/* Refblock is allocated, write it to disk */
|
|
|
|
ret = qcow2_pre_write_overlap_check(bs, 0, refblock_offset,
|
|
s->cluster_size, false);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret, "ERROR writing refblock");
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* The refblock is simply a slice of *refcount_table.
|
|
* Note that the size of *refcount_table is always aligned to
|
|
* whole clusters, so the write operation will not result in
|
|
* out-of-bounds accesses.
|
|
*/
|
|
on_disk_refblock = (void *)((char *) *refcount_table +
|
|
refblock_index * s->cluster_size);
|
|
|
|
ret = bdrv_pwrite(bs->file, refblock_offset, s->cluster_size,
|
|
on_disk_refblock, 0);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret, "ERROR writing refblock");
|
|
return ret;
|
|
}
|
|
|
|
/* This refblock is done, skip to its end */
|
|
cluster = refblock_start + s->refcount_block_size - 1;
|
|
}
|
|
|
|
return reftable_grown;
|
|
}
|
|
|
|
/*
|
|
* Creates a new refcount structure based solely on the in-memory information
|
|
* given through *refcount_table (this in-memory information is basically just
|
|
* the concatenation of all refblocks). 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,
|
|
Error **errp)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
int64_t reftable_offset = -1;
|
|
int64_t reftable_length = 0;
|
|
int64_t reftable_clusters;
|
|
int64_t refblock_index;
|
|
uint32_t on_disk_reftable_entries = 0;
|
|
uint64_t *on_disk_reftable = NULL;
|
|
int ret = 0;
|
|
int reftable_size_changed = 0;
|
|
struct {
|
|
uint64_t reftable_offset;
|
|
uint32_t reftable_clusters;
|
|
} QEMU_PACKED reftable_offset_and_clusters;
|
|
|
|
qcow2_cache_empty(bs, s->refcount_block_cache);
|
|
|
|
/*
|
|
* For each refblock containing entries, we try to allocate a
|
|
* cluster (in the in-memory refcount table) and write its offset
|
|
* into on_disk_reftable[]. We then write the whole refblock to
|
|
* disk (as a slice of the in-memory refcount table).
|
|
* This is done by rebuild_refcounts_write_refblocks().
|
|
*
|
|
* Once we have scanned all clusters, we try to find space for the
|
|
* reftable. This will dirty the in-memory refcount table (i.e.
|
|
* make it differ from the refblocks we have already written), so we
|
|
* need to run rebuild_refcounts_write_refblocks() again for the
|
|
* range of clusters where the reftable has been allocated.
|
|
*
|
|
* This second run might make the reftable grow again, in which case
|
|
* we will need to allocate another space for it, which is why we
|
|
* repeat all this until the reftable stops growing.
|
|
*
|
|
* (This loop will terminate, because with every cluster the
|
|
* reftable grows, it can accomodate a multitude of more refcounts,
|
|
* so that at some point this must be able to cover the reftable
|
|
* and all refblocks describing it.)
|
|
*
|
|
* We then convert the reftable to big-endian and write it to disk.
|
|
*
|
|
* Note that we never free any reftable allocations. Doing so would
|
|
* needlessly complicate the algorithm: The eventual second check
|
|
* run we do will clean up all leaks we have caused.
|
|
*/
|
|
|
|
reftable_size_changed =
|
|
rebuild_refcounts_write_refblocks(bs, refcount_table, nb_clusters,
|
|
0, *nb_clusters,
|
|
&on_disk_reftable,
|
|
&on_disk_reftable_entries, errp);
|
|
if (reftable_size_changed < 0) {
|
|
res->check_errors++;
|
|
ret = reftable_size_changed;
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* There was no reftable before, so rebuild_refcounts_write_refblocks()
|
|
* must have increased its size (from 0 to something).
|
|
*/
|
|
assert(reftable_size_changed);
|
|
|
|
do {
|
|
int64_t reftable_start_cluster, reftable_end_cluster;
|
|
int64_t first_free_cluster = 0;
|
|
|
|
reftable_length = on_disk_reftable_entries * REFTABLE_ENTRY_SIZE;
|
|
reftable_clusters = size_to_clusters(s, reftable_length);
|
|
|
|
reftable_offset = alloc_clusters_imrt(bs, reftable_clusters,
|
|
refcount_table, nb_clusters,
|
|
&first_free_cluster);
|
|
if (reftable_offset < 0) {
|
|
error_setg_errno(errp, -reftable_offset,
|
|
"ERROR allocating reftable");
|
|
res->check_errors++;
|
|
ret = reftable_offset;
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* We need to update the affected refblocks, so re-run the
|
|
* write_refblocks loop for the reftable's range of clusters.
|
|
*/
|
|
assert(offset_into_cluster(s, reftable_offset) == 0);
|
|
reftable_start_cluster = reftable_offset / s->cluster_size;
|
|
reftable_end_cluster = reftable_start_cluster + reftable_clusters;
|
|
reftable_size_changed =
|
|
rebuild_refcounts_write_refblocks(bs, refcount_table, nb_clusters,
|
|
reftable_start_cluster,
|
|
reftable_end_cluster,
|
|
&on_disk_reftable,
|
|
&on_disk_reftable_entries, errp);
|
|
if (reftable_size_changed < 0) {
|
|
res->check_errors++;
|
|
ret = reftable_size_changed;
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* If the reftable size has changed, we will need to find a new
|
|
* allocation, repeating the loop.
|
|
*/
|
|
} while (reftable_size_changed);
|
|
|
|
/* The above loop must have run at least once */
|
|
assert(reftable_offset >= 0);
|
|
|
|
/*
|
|
* All allocations are done, all refblocks are written, convert the
|
|
* reftable to big-endian and write it to disk.
|
|
*/
|
|
|
|
for (refblock_index = 0; refblock_index < on_disk_reftable_entries;
|
|
refblock_index++)
|
|
{
|
|
cpu_to_be64s(&on_disk_reftable[refblock_index]);
|
|
}
|
|
|
|
ret = qcow2_pre_write_overlap_check(bs, 0, reftable_offset, reftable_length,
|
|
false);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret, "ERROR writing reftable");
|
|
goto fail;
|
|
}
|
|
|
|
assert(reftable_length < INT_MAX);
|
|
ret = bdrv_pwrite(bs->file, reftable_offset, reftable_length,
|
|
on_disk_reftable, 0);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret, "ERROR writing reftable");
|
|
goto fail;
|
|
}
|
|
|
|
/* Enter new reftable into the image header */
|
|
reftable_offset_and_clusters.reftable_offset = cpu_to_be64(reftable_offset);
|
|
reftable_offset_and_clusters.reftable_clusters =
|
|
cpu_to_be32(reftable_clusters);
|
|
ret = bdrv_pwrite_sync(bs->file,
|
|
offsetof(QCowHeader, refcount_table_offset),
|
|
sizeof(reftable_offset_and_clusters),
|
|
&reftable_offset_and_clusters, 0);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret, "ERROR setting reftable");
|
|
goto fail;
|
|
}
|
|
|
|
for (refblock_index = 0; refblock_index < on_disk_reftable_entries;
|
|
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 = on_disk_reftable_entries;
|
|
update_max_refcount_table_index(s);
|
|
|
|
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;
|
|
Error *local_err = NULL;
|
|
|
|
fprintf(stderr, "Rebuilding refcount structure\n");
|
|
ret = rebuild_refcount_structure(bs, res, &refcount_table,
|
|
&nb_clusters, &local_err);
|
|
if (ret < 0) {
|
|
error_report_err(local_err);
|
|
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_pread 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 = ROUND_UP(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 * L1E_SIZE)) {
|
|
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 * REFTABLE_ENTRY_SIZE)) {
|
|
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 * L1E_SIZE)) {
|
|
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) {
|
|
unsigned last_entry = s->max_refcount_table_index;
|
|
assert(last_entry < s->refcount_table_size);
|
|
assert(last_entry + 1 == s->refcount_table_size ||
|
|
(s->refcount_table[last_entry + 1] & REFT_OFFSET_MASK) == 0);
|
|
for (i = 0; i <= last_entry; 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 * L1E_SIZE;
|
|
uint64_t *l1;
|
|
int ret;
|
|
|
|
ret = qcow2_validate_table(bs, l1_ofs, l1_sz, L1E_SIZE,
|
|
QCOW_MAX_L1_SIZE, "", NULL);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
l1 = g_try_malloc(l1_sz2);
|
|
|
|
if (l1_sz2 && l1 == NULL) {
|
|
return -ENOMEM;
|
|
}
|
|
|
|
ret = bdrv_pread(bs->file, l1_ofs, l1_sz2, l1, 0);
|
|
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);
|
|
}
|
|
}
|
|
|
|
if ((chk & QCOW2_OL_BITMAP_DIRECTORY) &&
|
|
(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS))
|
|
{
|
|
if (overlaps_with(s->bitmap_directory_offset,
|
|
s->bitmap_directory_size))
|
|
{
|
|
return QCOW2_OL_BITMAP_DIRECTORY;
|
|
}
|
|
}
|
|
|
|
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",
|
|
[QCOW2_OL_BITMAP_DIRECTORY_BITNR] = "bitmap directory",
|
|
};
|
|
QEMU_BUILD_BUG_ON(QCOW2_OL_MAX_BITNR != ARRAY_SIZE(metadata_ol_names));
|
|
|
|
/*
|
|
* 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, bool data_file)
|
|
{
|
|
int ret;
|
|
|
|
if (data_file && has_data_file(bs)) {
|
|
return 0;
|
|
}
|
|
|
|
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 / REFTABLE_ENTRY_SIZE);
|
|
if (new_reftable_size > QCOW_MAX_REFTABLE_SIZE / REFTABLE_ENTRY_SIZE) {
|
|
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 *
|
|
REFTABLE_ENTRY_SIZE);
|
|
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) * REFTABLE_ENTRY_SIZE);
|
|
|
|
*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,
|
|
false);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret, "Overlap check failed");
|
|
return ret;
|
|
}
|
|
|
|
ret = bdrv_pwrite(bs->file, offset, s->cluster_size, refblock, 0);
|
|
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(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(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(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 * REFTABLE_ENTRY_SIZE,
|
|
QCOW2_DISCARD_NEVER);
|
|
}
|
|
|
|
new_reftable_offset = qcow2_alloc_clusters(bs, new_reftable_size *
|
|
REFTABLE_ENTRY_SIZE);
|
|
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 * REFTABLE_ENTRY_SIZE,
|
|
false);
|
|
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, new_reftable_offset,
|
|
new_reftable_size * REFTABLE_ENTRY_SIZE, new_reftable,
|
|
0);
|
|
|
|
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;
|
|
update_max_refcount_table_index(s);
|
|
|
|
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 * REFTABLE_ENTRY_SIZE,
|
|
QCOW2_DISCARD_OTHER);
|
|
}
|
|
}
|
|
|
|
qemu_vfree(new_refblock);
|
|
return ret;
|
|
}
|
|
|
|
static int64_t get_refblock_offset(BlockDriverState *bs, uint64_t offset)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
uint32_t index = offset_to_reftable_index(s, offset);
|
|
int64_t covering_refblock_offset = 0;
|
|
|
|
if (index < s->refcount_table_size) {
|
|
covering_refblock_offset = s->refcount_table[index] & REFT_OFFSET_MASK;
|
|
}
|
|
if (!covering_refblock_offset) {
|
|
qcow2_signal_corruption(bs, true, -1, -1, "Refblock at %#" PRIx64 " is "
|
|
"not covered by the refcount structures",
|
|
offset);
|
|
return -EIO;
|
|
}
|
|
|
|
return covering_refblock_offset;
|
|
}
|
|
|
|
static int coroutine_fn
|
|
qcow2_discard_refcount_block(BlockDriverState *bs, uint64_t discard_block_offs)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
int64_t refblock_offs;
|
|
uint64_t cluster_index = discard_block_offs >> s->cluster_bits;
|
|
uint32_t block_index = cluster_index & (s->refcount_block_size - 1);
|
|
void *refblock;
|
|
int ret;
|
|
|
|
refblock_offs = get_refblock_offset(bs, discard_block_offs);
|
|
if (refblock_offs < 0) {
|
|
return refblock_offs;
|
|
}
|
|
|
|
assert(discard_block_offs != 0);
|
|
|
|
ret = qcow2_cache_get(bs, s->refcount_block_cache, refblock_offs,
|
|
&refblock);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
if (s->get_refcount(refblock, block_index) != 1) {
|
|
qcow2_signal_corruption(bs, true, -1, -1, "Invalid refcount:"
|
|
" refblock offset %#" PRIx64
|
|
", reftable index %u"
|
|
", block offset %#" PRIx64
|
|
", refcount %#" PRIx64,
|
|
refblock_offs,
|
|
offset_to_reftable_index(s, discard_block_offs),
|
|
discard_block_offs,
|
|
s->get_refcount(refblock, block_index));
|
|
qcow2_cache_put(s->refcount_block_cache, &refblock);
|
|
return -EINVAL;
|
|
}
|
|
s->set_refcount(refblock, block_index, 0);
|
|
|
|
qcow2_cache_entry_mark_dirty(s->refcount_block_cache, refblock);
|
|
|
|
qcow2_cache_put(s->refcount_block_cache, &refblock);
|
|
|
|
if (cluster_index < s->free_cluster_index) {
|
|
s->free_cluster_index = cluster_index;
|
|
}
|
|
|
|
refblock = qcow2_cache_is_table_offset(s->refcount_block_cache,
|
|
discard_block_offs);
|
|
if (refblock) {
|
|
/* discard refblock from the cache if refblock is cached */
|
|
qcow2_cache_discard(s->refcount_block_cache, refblock);
|
|
}
|
|
update_refcount_discard(bs, discard_block_offs, s->cluster_size);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int coroutine_fn qcow2_shrink_reftable(BlockDriverState *bs)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
uint64_t *reftable_tmp =
|
|
g_malloc(s->refcount_table_size * REFTABLE_ENTRY_SIZE);
|
|
int i, ret;
|
|
|
|
for (i = 0; i < s->refcount_table_size; i++) {
|
|
int64_t refblock_offs = s->refcount_table[i] & REFT_OFFSET_MASK;
|
|
void *refblock;
|
|
bool unused_block;
|
|
|
|
if (refblock_offs == 0) {
|
|
reftable_tmp[i] = 0;
|
|
continue;
|
|
}
|
|
ret = qcow2_cache_get(bs, s->refcount_block_cache, refblock_offs,
|
|
&refblock);
|
|
if (ret < 0) {
|
|
goto out;
|
|
}
|
|
|
|
/* the refblock has own reference */
|
|
if (i == offset_to_reftable_index(s, refblock_offs)) {
|
|
uint64_t block_index = (refblock_offs >> s->cluster_bits) &
|
|
(s->refcount_block_size - 1);
|
|
uint64_t refcount = s->get_refcount(refblock, block_index);
|
|
|
|
s->set_refcount(refblock, block_index, 0);
|
|
|
|
unused_block = buffer_is_zero(refblock, s->cluster_size);
|
|
|
|
s->set_refcount(refblock, block_index, refcount);
|
|
} else {
|
|
unused_block = buffer_is_zero(refblock, s->cluster_size);
|
|
}
|
|
qcow2_cache_put(s->refcount_block_cache, &refblock);
|
|
|
|
reftable_tmp[i] = unused_block ? 0 : cpu_to_be64(s->refcount_table[i]);
|
|
}
|
|
|
|
ret = bdrv_pwrite_sync(bs->file, s->refcount_table_offset,
|
|
s->refcount_table_size * REFTABLE_ENTRY_SIZE,
|
|
reftable_tmp, 0);
|
|
/*
|
|
* If the write in the reftable failed the image may contain a partially
|
|
* overwritten reftable. In this case it would be better to clear the
|
|
* reftable in memory to avoid possible image corruption.
|
|
*/
|
|
for (i = 0; i < s->refcount_table_size; i++) {
|
|
if (s->refcount_table[i] && !reftable_tmp[i]) {
|
|
if (ret == 0) {
|
|
ret = qcow2_discard_refcount_block(bs, s->refcount_table[i] &
|
|
REFT_OFFSET_MASK);
|
|
}
|
|
s->refcount_table[i] = 0;
|
|
}
|
|
}
|
|
|
|
if (!s->cache_discards) {
|
|
qcow2_process_discards(bs, ret);
|
|
}
|
|
|
|
out:
|
|
g_free(reftable_tmp);
|
|
return ret;
|
|
}
|
|
|
|
int64_t qcow2_get_last_cluster(BlockDriverState *bs, int64_t size)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
int64_t i;
|
|
|
|
for (i = size_to_clusters(s, size) - 1; i >= 0; i--) {
|
|
uint64_t refcount;
|
|
int ret = qcow2_get_refcount(bs, i, &refcount);
|
|
if (ret < 0) {
|
|
fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n",
|
|
i, strerror(-ret));
|
|
return ret;
|
|
}
|
|
if (refcount > 0) {
|
|
return i;
|
|
}
|
|
}
|
|
qcow2_signal_corruption(bs, true, -1, -1,
|
|
"There are no references in the refcount table.");
|
|
return -EIO;
|
|
}
|
|
|
|
int coroutine_fn qcow2_detect_metadata_preallocation(BlockDriverState *bs)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
int64_t i, end_cluster, cluster_count = 0, threshold;
|
|
int64_t file_length, real_allocation, real_clusters;
|
|
|
|
qemu_co_mutex_assert_locked(&s->lock);
|
|
|
|
file_length = bdrv_getlength(bs->file->bs);
|
|
if (file_length < 0) {
|
|
return file_length;
|
|
}
|
|
|
|
real_allocation = bdrv_get_allocated_file_size(bs->file->bs);
|
|
if (real_allocation < 0) {
|
|
return real_allocation;
|
|
}
|
|
|
|
real_clusters = real_allocation / s->cluster_size;
|
|
threshold = MAX(real_clusters * 10 / 9, real_clusters + 2);
|
|
|
|
end_cluster = size_to_clusters(s, file_length);
|
|
for (i = 0; i < end_cluster && cluster_count < threshold; i++) {
|
|
uint64_t refcount;
|
|
int ret = qcow2_get_refcount(bs, i, &refcount);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
cluster_count += !!refcount;
|
|
}
|
|
|
|
return cluster_count >= threshold;
|
|
}
|