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qcow2: Refcount checking code cleanup (Kevin Wolf)
This is purely cosmetical changes to make the code easier to read. Move L2 table processing from a deeply nested block to its own function, add some comments. Patch v2: Fix misplaced bracket causing false positives Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7216 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori
parent
1585969c6e
commit
ae2f14af54
149
block-qcow2.c
149
block-qcow2.c
@ -2603,6 +2603,90 @@ static int inc_refcounts(BlockDriverState *bs,
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return errors;
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}
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/*
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* Increases the refcount in the given refcount table for the all clusters
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* referenced in the L2 table. While doing so, performs some checks on L2
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* entries.
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*
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* Returns the number of errors found by the checks or -errno if an internal
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* error occurred.
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*/
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static int check_refcounts_l2(BlockDriverState *bs,
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uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset,
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int check_copied)
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{
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BDRVQcowState *s = bs->opaque;
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uint64_t *l2_table, offset;
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int i, l2_size, nb_csectors, refcount;
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int errors = 0;
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/* Read L2 table from disk */
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l2_size = s->l2_size * sizeof(uint64_t);
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l2_table = qemu_malloc(l2_size);
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if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
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goto fail;
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/* Do the actual checks */
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for(i = 0; i < s->l2_size; i++) {
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offset = be64_to_cpu(l2_table[i]);
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if (offset != 0) {
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if (offset & QCOW_OFLAG_COMPRESSED) {
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/* Compressed clusters don't have QCOW_OFLAG_COPIED */
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if (offset & QCOW_OFLAG_COPIED) {
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fprintf(stderr, "ERROR: cluster %" PRId64 ": "
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"copied flag must never be set for compressed "
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"clusters\n", offset >> s->cluster_bits);
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offset &= ~QCOW_OFLAG_COPIED;
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errors++;
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}
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/* Mark cluster as used */
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nb_csectors = ((offset >> s->csize_shift) &
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s->csize_mask) + 1;
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offset &= s->cluster_offset_mask;
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errors += inc_refcounts(bs, refcount_table,
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refcount_table_size,
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offset & ~511, nb_csectors * 512);
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} else {
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/* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
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if (check_copied) {
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uint64_t entry = offset;
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offset &= ~QCOW_OFLAG_COPIED;
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refcount = get_refcount(bs, offset >> s->cluster_bits);
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if ((refcount == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) {
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fprintf(stderr, "ERROR OFLAG_COPIED: offset=%"
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PRIx64 " refcount=%d\n", entry, refcount);
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errors++;
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}
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}
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/* Mark cluster as used */
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offset &= ~QCOW_OFLAG_COPIED;
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errors += inc_refcounts(bs, refcount_table,
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refcount_table_size,
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offset, s->cluster_size);
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}
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}
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}
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qemu_free(l2_table);
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return errors;
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fail:
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fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
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qemu_free(l2_table);
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return -EIO;
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}
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/*
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* Increases the refcount for the L1 table, its L2 tables and all referenced
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* clusters in the given refcount table. While doing so, performs some checks
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* on L1 and L2 entries.
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*
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* Returns the number of errors found by the checks or -errno if an internal
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* error occurred.
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*/
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static int check_refcounts_l1(BlockDriverState *bs,
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uint16_t *refcount_table,
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int refcount_table_size,
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@ -2610,16 +2694,17 @@ static int check_refcounts_l1(BlockDriverState *bs,
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int check_copied)
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{
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BDRVQcowState *s = bs->opaque;
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uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2;
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int l2_size, i, j, nb_csectors, refcount;
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uint64_t *l1_table, l2_offset, l1_size2;
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int i, refcount, ret;
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int errors = 0;
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l2_table = NULL;
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l1_size2 = l1_size * sizeof(uint64_t);
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/* Mark L1 table as used */
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errors += inc_refcounts(bs, refcount_table, refcount_table_size,
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l1_table_offset, l1_size2);
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/* Read L1 table entries from disk */
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l1_table = qemu_malloc(l1_size2);
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if (bdrv_pread(s->hd, l1_table_offset,
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l1_table, l1_size2) != l1_size2)
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@ -2627,68 +2712,43 @@ static int check_refcounts_l1(BlockDriverState *bs,
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for(i = 0;i < l1_size; i++)
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be64_to_cpus(&l1_table[i]);
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l2_size = s->l2_size * sizeof(uint64_t);
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l2_table = qemu_malloc(l2_size);
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/* Do the actual checks */
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for(i = 0; i < l1_size; i++) {
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l2_offset = l1_table[i];
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if (l2_offset) {
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/* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
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if (check_copied) {
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refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits);
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refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED)
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>> s->cluster_bits);
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if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) {
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fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64
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" refcount=%d\n", l2_offset, refcount);
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errors++;
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}
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}
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/* Mark L2 table as used */
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l2_offset &= ~QCOW_OFLAG_COPIED;
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if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
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goto fail;
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for(j = 0; j < s->l2_size; j++) {
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offset = be64_to_cpu(l2_table[j]);
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if (offset != 0) {
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if (offset & QCOW_OFLAG_COMPRESSED) {
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if (offset & QCOW_OFLAG_COPIED) {
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fprintf(stderr, "ERROR: cluster %" PRId64 ": "
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"copied flag must never be set for compressed "
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"clusters\n", offset >> s->cluster_bits);
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offset &= ~QCOW_OFLAG_COPIED;
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errors++;
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}
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nb_csectors = ((offset >> s->csize_shift) &
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s->csize_mask) + 1;
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offset &= s->cluster_offset_mask;
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errors += inc_refcounts(bs, refcount_table,
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refcount_table_size,
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offset & ~511, nb_csectors * 512);
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} else {
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if (check_copied) {
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refcount = get_refcount(bs, (offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits);
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if ((refcount == 1) != ((offset & QCOW_OFLAG_COPIED) != 0)) {
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fprintf(stderr, "ERROR OFLAG_COPIED: offset=%"
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PRIx64 " refcount=%d\n", offset, refcount);
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errors++;
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}
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}
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offset &= ~QCOW_OFLAG_COPIED;
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errors += inc_refcounts(bs, refcount_table,
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refcount_table_size,
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offset, s->cluster_size);
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}
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}
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}
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errors += inc_refcounts(bs, refcount_table,
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refcount_table_size,
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l2_offset,
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s->cluster_size);
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/* Process and check L2 entries */
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ret = check_refcounts_l2(bs, refcount_table, refcount_table_size,
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l2_offset, check_copied);
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if (ret < 0) {
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goto fail;
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}
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errors += ret;
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}
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}
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qemu_free(l1_table);
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qemu_free(l2_table);
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return errors;
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fail:
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fail:
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fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
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qemu_free(l1_table);
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qemu_free(l2_table);
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return -EIO;
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}
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@ -2715,6 +2775,7 @@ static int check_refcounts(BlockDriverState *bs)
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errors += inc_refcounts(bs, refcount_table, nb_clusters,
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0, s->cluster_size);
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/* current L1 table */
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ret = check_refcounts_l1(bs, refcount_table, nb_clusters,
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s->l1_table_offset, s->l1_size, 1);
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if (ret < 0) {
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