diff options
| -rw-r--r-- | block/qcow2-refcount.c | 41 |
1 files changed, 37 insertions, 4 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 22b0b45ff7..ca6b373b8b 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -105,11 +105,17 @@ static int load_refcount_block(BlockDriverState *bs, return 0; } +/* + * Returns the refcount of the cluster given by its index. Any non-negative + * return value is the refcount of the cluster, negative values are -errno + * and indicate an error. + */ static int get_refcount(BlockDriverState *bs, int64_t cluster_index) { BDRVQcowState *s = bs->opaque; int refcount_table_index, block_index; int64_t refcount_block_offset; + int ret; refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); if (refcount_table_index >= s->refcount_table_size) @@ -119,8 +125,10 @@ static int get_refcount(BlockDriverState *bs, int64_t cluster_index) return 0; if (refcount_block_offset != s->refcount_block_cache_offset) { /* better than nothing: return allocated if read error */ - if (load_refcount_block(bs, refcount_block_offset) < 0) - return 1; + ret = load_refcount_block(bs, refcount_block_offset); + if (ret < 0) { + return ret; + } } block_index = cluster_index & ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); @@ -538,7 +546,13 @@ fail: return ret; } -/* addend must be 1 or -1 */ +/* + * Increases or decreases the refcount of a given cluster by one. + * addend must be 1 or -1. + * + * If the return value is non-negative, it is the new refcount of the cluster. + * If it is negative, it is -errno and indicates an error. + */ static int update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index, int addend) @@ -779,6 +793,10 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, } else { refcount = get_refcount(bs, offset >> s->cluster_bits); } + + if (refcount < 0) { + goto fail; + } } if (refcount == 1) { @@ -801,7 +819,9 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, } else { refcount = get_refcount(bs, l2_offset >> s->cluster_bits); } - if (refcount == 1) { + if (refcount < 0) { + goto fail; + } else if (refcount == 1) { l2_offset |= QCOW_OFLAG_COPIED; } if (l2_offset != old_l2_offset) { @@ -934,6 +954,10 @@ static int check_refcounts_l2(BlockDriverState *bs, uint64_t entry = offset; offset &= ~QCOW_OFLAG_COPIED; refcount = get_refcount(bs, offset >> s->cluster_bits); + if (refcount < 0) { + fprintf(stderr, "Can't get refcount for offset %" + PRIx64 ": %s\n", entry, strerror(-refcount)); + } if ((refcount == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) { fprintf(stderr, "ERROR OFLAG_COPIED: offset=%" PRIx64 " refcount=%d\n", entry, refcount); @@ -1011,6 +1035,10 @@ static int check_refcounts_l1(BlockDriverState *bs, if (check_copied) { refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits); + if (refcount < 0) { + fprintf(stderr, "Can't get refcount for l2_offset %" + PRIx64 ": %s\n", l2_offset, strerror(-refcount)); + } if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) { fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64 " refcount=%d\n", l2_offset, refcount); @@ -1118,6 +1146,11 @@ int qcow2_check_refcounts(BlockDriverState *bs) /* compare ref counts */ for(i = 0; i < nb_clusters; i++) { refcount1 = get_refcount(bs, i); + if (refcount1 < 0) { + fprintf(stderr, "Can't get refcount for cluster %d: %s\n", + i, strerror(-refcount1)); + } + refcount2 = refcount_table[i]; if (refcount1 != refcount2) { fprintf(stderr, "ERROR cluster %d refcount=%d reference=%d\n", |