*/
#include "qemu-common.h"
-#include "block_int.h"
+#include "block/block_int.h"
#include "block/qcow2.h"
+#include "qemu/range.h"
+#include "qapi/qmp/types.h"
static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size);
static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs,
int64_t offset, int64_t length,
- int addend);
+ int addend, enum qcow2_discard_type type);
/*********************************************************/
*refcount_block = NULL;
/* We write to the refcount table, so we might depend on L2 tables */
- qcow2_cache_flush(bs, s->l2_table_cache);
+ ret = qcow2_cache_flush(bs, s->l2_table_cache);
+ if (ret < 0) {
+ return ret;
+ }
/* Allocate the refcount block itself and mark it as used */
int64_t new_block = alloc_clusters_noref(bs, s->cluster_size);
} 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);
+ ret = update_refcount(bs, new_block, s->cluster_size, 1,
+ QCOW2_DISCARD_NEVER);
if (ret < 0) {
goto fail_block;
}
- bdrv_flush(bs->file);
+ ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+ if (ret < 0) {
+ goto fail_block;
+ }
/* Initialize the new refcount block only after updating its refcount,
* update_refcount uses the refcount cache itself */
uint64_t last_table_size;
uint64_t blocks_clusters;
do {
- uint64_t table_clusters = size_to_clusters(s, table_size);
+ uint64_t table_clusters =
+ size_to_clusters(s, table_size * sizeof(uint64_t));
blocks_clusters = 1 +
((table_clusters + refcount_block_clusters - 1)
/ refcount_block_clusters);
}
for(i = 0; i < table_size; i++) {
- cpu_to_be64s(&new_table[i]);
+ be64_to_cpus(&new_table[i]);
}
/* Hook up the new refcount table in the qcow2 header */
/* Free old table. Remember, we must not change free_cluster_index */
uint64_t old_free_cluster_index = s->free_cluster_index;
- qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t));
+ qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t),
+ QCOW2_DISCARD_OTHER);
s->free_cluster_index = old_free_cluster_index;
ret = load_refcount_block(bs, new_block, (void**) refcount_block);
return ret;
}
+void qcow2_process_discards(BlockDriverState *bs, int ret)
+{
+ BDRVQcowState *s = bs->opaque;
+ Qcow2DiscardRegion *d, *next;
+
+ QTAILQ_FOREACH_SAFE(d, &s->discards, next, next) {
+ QTAILQ_REMOVE(&s->discards, d, next);
+
+ /* Discard is optional, ignore the return value */
+ if (ret >= 0) {
+ bdrv_discard(bs->file,
+ d->offset >> BDRV_SECTOR_BITS,
+ d->bytes >> BDRV_SECTOR_BITS);
+ }
+
+ g_free(d);
+ }
+}
+
+static void update_refcount_discard(BlockDriverState *bs,
+ uint64_t offset, uint64_t length)
+{
+ BDRVQcowState *s = bs->opaque;
+ Qcow2DiscardRegion *d, *p, *next;
+
+ QTAILQ_FOREACH(d, &s->discards, next) {
+ uint64_t new_start = MIN(offset, d->offset);
+ uint64_t new_end = MAX(offset + length, d->offset + d->bytes);
+
+ if (new_end - new_start <= length + d->bytes) {
+ /* There can't be any overlap, areas ending up here have no
+ * references any more and therefore shouldn't get freed another
+ * time. */
+ assert(d->bytes + length == new_end - new_start);
+ d->offset = new_start;
+ d->bytes = new_end - new_start;
+ goto found;
+ }
+ }
+
+ d = g_malloc(sizeof(*d));
+ *d = (Qcow2DiscardRegion) {
+ .bs = bs,
+ .offset = offset,
+ .bytes = length,
+ };
+ QTAILQ_INSERT_TAIL(&s->discards, d, next);
+
+found:
+ /* Merge discard requests if they are adjacent now */
+ QTAILQ_FOREACH_SAFE(p, &s->discards, next, next) {
+ if (p == d
+ || p->offset > d->offset + d->bytes
+ || d->offset > p->offset + p->bytes)
+ {
+ continue;
+ }
+
+ /* Still no overlap possible */
+ assert(p->offset == d->offset + d->bytes
+ || d->offset == p->offset + p->bytes);
+
+ QTAILQ_REMOVE(&s->discards, p, next);
+ d->offset = MIN(d->offset, p->offset);
+ d->bytes += p->bytes;
+ }
+}
+
/* XXX: cache several refcount block clusters ? */
static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs,
- int64_t offset, int64_t length, int addend)
+ int64_t offset, int64_t length, int addend, enum qcow2_discard_type type)
{
BDRVQcowState *s = bs->opaque;
int64_t start, last, cluster_offset;
s->free_cluster_index = cluster_index;
}
refcount_block[block_index] = cpu_to_be16(refcount);
+
+ if (refcount == 0 && s->discard_passthrough[type]) {
+ update_refcount_discard(bs, cluster_offset, s->cluster_size);
+ }
}
ret = 0;
fail:
+ if (!s->cache_discards) {
+ qcow2_process_discards(bs, ret);
+ }
+
/* Write last changed block to disk */
if (refcount_block) {
int wret;
*/
if (ret < 0) {
int dummy;
- dummy = update_refcount(bs, offset, cluster_offset - offset, -addend);
+ dummy = update_refcount(bs, offset, cluster_offset - offset, -addend,
+ QCOW2_DISCARD_NEVER);
(void)dummy;
}
*/
static int update_cluster_refcount(BlockDriverState *bs,
int64_t cluster_index,
- int addend)
+ int addend,
+ enum qcow2_discard_type type)
{
BDRVQcowState *s = bs->opaque;
int ret;
- ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend);
+ ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend,
+ type);
if (ret < 0) {
return ret;
}
- bdrv_flush(bs->file);
-
return get_refcount(bs, cluster_index);
}
return offset;
}
- ret = update_refcount(bs, offset, size, 1);
+ ret = update_refcount(bs, offset, size, 1, QCOW2_DISCARD_NEVER);
if (ret < 0) {
return ret;
}
old_free_cluster_index = s->free_cluster_index;
s->free_cluster_index = cluster_index + i;
- ret = update_refcount(bs, offset, i << s->cluster_bits, 1);
+ ret = update_refcount(bs, offset, i << s->cluster_bits, 1,
+ QCOW2_DISCARD_NEVER);
if (ret < 0) {
return ret;
}
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES);
assert(size > 0 && size <= s->cluster_size);
if (s->free_byte_offset == 0) {
- s->free_byte_offset = qcow2_alloc_clusters(bs, s->cluster_size);
- if (s->free_byte_offset < 0) {
- return s->free_byte_offset;
+ offset = qcow2_alloc_clusters(bs, s->cluster_size);
+ if (offset < 0) {
+ return offset;
}
+ s->free_byte_offset = offset;
}
redo:
free_in_cluster = s->cluster_size -
if (free_in_cluster == 0)
s->free_byte_offset = 0;
if ((offset & (s->cluster_size - 1)) != 0)
- update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
+ update_cluster_refcount(bs, offset >> s->cluster_bits, 1,
+ QCOW2_DISCARD_NEVER);
} else {
offset = qcow2_alloc_clusters(bs, s->cluster_size);
if (offset < 0) {
if ((cluster_offset + s->cluster_size) == offset) {
/* we are lucky: contiguous data */
offset = s->free_byte_offset;
- update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
+ update_cluster_refcount(bs, offset >> s->cluster_bits, 1,
+ QCOW2_DISCARD_NEVER);
s->free_byte_offset += size;
} else {
s->free_byte_offset = offset;
}
}
- bdrv_flush(bs->file);
+ /* The cluster refcount was incremented, either by qcow2_alloc_clusters()
+ * or explicitly by update_cluster_refcount(). Refcount blocks must be
+ * flushed before the caller's L2 table updates.
+ */
+ qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache);
return offset;
}
void qcow2_free_clusters(BlockDriverState *bs,
- int64_t offset, int64_t size)
+ 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);
+ ret = update_refcount(bs, offset, size, -1, type);
if (ret < 0) {
fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret));
/* TODO Remember the clusters to free them later and avoid leaking */
* Free a cluster using its L2 entry (handles clusters of all types, e.g.
* normal cluster, compressed cluster, etc.)
*/
-void qcow2_free_any_clusters(BlockDriverState *bs,
- uint64_t l2_entry, int nb_clusters)
+void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
+ int nb_clusters, enum qcow2_discard_type type)
{
BDRVQcowState *s = bs->opaque;
s->csize_mask) + 1;
qcow2_free_clusters(bs,
(l2_entry & s->cluster_offset_mask) & ~511,
- nb_csectors * 512);
+ nb_csectors * 512, type);
}
break;
case QCOW2_CLUSTER_NORMAL:
qcow2_free_clusters(bs, l2_entry & L2E_OFFSET_MASK,
- nb_clusters << s->cluster_bits);
+ nb_clusters << s->cluster_bits, type);
break;
case QCOW2_CLUSTER_UNALLOCATED:
+ case QCOW2_CLUSTER_ZERO:
break;
default:
abort();
int64_t old_offset, old_l2_offset;
int i, j, l1_modified = 0, nb_csectors, refcount;
int ret;
- bool old_l2_writethrough, old_refcount_writethrough;
-
- /* Switch caches to writeback mode during update */
- old_l2_writethrough =
- qcow2_cache_set_writethrough(bs, s->l2_table_cache, false);
- old_refcount_writethrough =
- qcow2_cache_set_writethrough(bs, s->refcount_block_cache, false);
l2_table = NULL;
l1_table = NULL;
l1_size2 = l1_size * sizeof(uint64_t);
+ s->cache_discards = true;
+
/* WARNING: qcow2_snapshot_goto relies on this function not using the
* l1_table_offset when it is the current s->l1_table_offset! Be careful
* when changing this! */
if (l1_table_offset != s->l1_table_offset) {
- if (l1_size2 != 0) {
- l1_table = g_malloc0(align_offset(l1_size2, 512));
- } else {
- l1_table = NULL;
- }
+ l1_table = g_malloc0(align_offset(l1_size2, 512));
l1_allocated = 1;
- if (bdrv_pread(bs->file, l1_table_offset,
- l1_table, l1_size2) != l1_size2)
- {
- ret = -EIO;
+
+ ret = bdrv_pread(bs->file, l1_table_offset, l1_table, l1_size2);
+ if (ret < 0) {
goto fail;
}
}
for(j = 0; j < s->l2_size; j++) {
+ uint64_t cluster_index;
+
offset = be64_to_cpu(l2_table[j]);
- if (offset != 0) {
- old_offset = offset;
- offset &= ~QCOW_OFLAG_COPIED;
- if (offset & QCOW_OFLAG_COMPRESSED) {
+ old_offset = offset;
+ offset &= ~QCOW_OFLAG_COPIED;
+
+ switch (qcow2_get_cluster_type(offset)) {
+ case QCOW2_CLUSTER_COMPRESSED:
nb_csectors = ((offset >> s->csize_shift) &
s->csize_mask) + 1;
if (addend != 0) {
int ret;
ret = update_refcount(bs,
(offset & s->cluster_offset_mask) & ~511,
- nb_csectors * 512, addend);
+ nb_csectors * 512, addend,
+ QCOW2_DISCARD_SNAPSHOT);
if (ret < 0) {
goto fail;
}
-
- /* TODO Flushing once for the whole function should
- * be enough */
- bdrv_flush(bs->file);
}
/* compressed clusters are never modified */
refcount = 2;
- } else {
- uint64_t cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits;
+ break;
+
+ case QCOW2_CLUSTER_NORMAL:
+ case QCOW2_CLUSTER_ZERO:
+ cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits;
+ if (!cluster_index) {
+ /* unallocated */
+ refcount = 0;
+ break;
+ }
if (addend != 0) {
- refcount = update_cluster_refcount(bs, cluster_index, addend);
+ refcount = update_cluster_refcount(bs, cluster_index, addend,
+ QCOW2_DISCARD_SNAPSHOT);
} else {
refcount = get_refcount(bs, cluster_index);
}
if (refcount < 0) {
- ret = -EIO;
+ ret = refcount;
goto fail;
}
- }
+ break;
- if (refcount == 1) {
- offset |= QCOW_OFLAG_COPIED;
- }
- if (offset != old_offset) {
- if (addend > 0) {
- qcow2_cache_set_dependency(bs, s->l2_table_cache,
- s->refcount_block_cache);
- }
- l2_table[j] = cpu_to_be64(offset);
- qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
+ case QCOW2_CLUSTER_UNALLOCATED:
+ refcount = 0;
+ break;
+
+ default:
+ abort();
+ }
+
+ if (refcount == 1) {
+ offset |= QCOW_OFLAG_COPIED;
+ }
+ if (offset != old_offset) {
+ if (addend > 0) {
+ qcow2_cache_set_dependency(bs, s->l2_table_cache,
+ s->refcount_block_cache);
}
+ l2_table[j] = cpu_to_be64(offset);
+ qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
}
}
if (addend != 0) {
- refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend);
+ refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend,
+ QCOW2_DISCARD_SNAPSHOT);
} else {
refcount = get_refcount(bs, l2_offset >> s->cluster_bits);
}
if (refcount < 0) {
- ret = -EIO;
+ ret = refcount;
goto fail;
} else if (refcount == 1) {
l2_offset |= QCOW_OFLAG_COPIED;
}
}
- ret = 0;
+ ret = bdrv_flush(bs);
fail:
if (l2_table) {
qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
}
- /* Enable writethrough cache mode again */
- qcow2_cache_set_writethrough(bs, s->l2_table_cache, old_l2_writethrough);
- qcow2_cache_set_writethrough(bs, s->refcount_block_cache,
- old_refcount_writethrough);
+ s->cache_discards = false;
+ qcow2_process_discards(bs, ret);
/* Update L1 only if it isn't deleted anyway (addend = -1) */
- if (addend >= 0 && l1_modified) {
- for(i = 0; i < l1_size; i++)
+ if (ret == 0 && addend >= 0 && l1_modified) {
+ for (i = 0; i < l1_size; i++) {
cpu_to_be64s(&l1_table[i]);
- if (bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table,
- l1_size2) < 0)
- goto fail;
- for(i = 0; i < l1_size; i++)
+ }
+
+ ret = bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table, l1_size2);
+
+ for (i = 0; i < l1_size; i++) {
be64_to_cpus(&l1_table[i]);
+ }
}
if (l1_allocated)
g_free(l1_table);
}
}
+/* Flags for check_refcounts_l1() and check_refcounts_l2() */
+enum {
+ CHECK_OFLAG_COPIED = 0x1, /* check QCOW_OFLAG_COPIED matches refcount */
+ CHECK_FRAG_INFO = 0x2, /* update BlockFragInfo counters */
+};
+
/*
* Increases the refcount in the given refcount table for the all clusters
* referenced in the L2 table. While doing so, performs some checks on L2
*/
static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset,
- int check_copied)
+ int flags)
{
BDRVQcowState *s = bs->opaque;
- uint64_t *l2_table, offset;
+ uint64_t *l2_table, l2_entry;
+ uint64_t next_contiguous_offset = 0;
int i, l2_size, nb_csectors, refcount;
/* Read L2 table from disk */
/* Do the actual checks */
for(i = 0; i < s->l2_size; i++) {
- offset = be64_to_cpu(l2_table[i]);
- if (offset != 0) {
- if (offset & QCOW_OFLAG_COMPRESSED) {
- /* Compressed clusters don't have QCOW_OFLAG_COPIED */
- if (offset & QCOW_OFLAG_COPIED) {
- fprintf(stderr, "ERROR: cluster %" PRId64 ": "
- "copied flag must never be set for compressed "
- "clusters\n", offset >> s->cluster_bits);
- offset &= ~QCOW_OFLAG_COPIED;
+ l2_entry = be64_to_cpu(l2_table[i]);
+
+ switch (qcow2_get_cluster_type(l2_entry)) {
+ case QCOW2_CLUSTER_COMPRESSED:
+ /* Compressed clusters don't have QCOW_OFLAG_COPIED */
+ if (l2_entry & QCOW_OFLAG_COPIED) {
+ fprintf(stderr, "ERROR: cluster %" PRId64 ": "
+ "copied flag must never be set for compressed "
+ "clusters\n", l2_entry >> s->cluster_bits);
+ l2_entry &= ~QCOW_OFLAG_COPIED;
+ res->corruptions++;
+ }
+
+ /* Mark cluster as used */
+ nb_csectors = ((l2_entry >> s->csize_shift) &
+ s->csize_mask) + 1;
+ l2_entry &= s->cluster_offset_mask;
+ inc_refcounts(bs, res, refcount_table, refcount_table_size,
+ l2_entry & ~511, nb_csectors * 512);
+
+ if (flags & CHECK_FRAG_INFO) {
+ res->bfi.allocated_clusters++;
+ res->bfi.compressed_clusters++;
+
+ /* Compressed clusters are fragmented by nature. Since they
+ * take up sub-sector space but we only have sector granularity
+ * I/O we need to re-read the same sectors even for adjacent
+ * compressed clusters.
+ */
+ res->bfi.fragmented_clusters++;
+ }
+ break;
+
+ case QCOW2_CLUSTER_ZERO:
+ if ((l2_entry & L2E_OFFSET_MASK) == 0) {
+ break;
+ }
+ /* fall through */
+
+ case QCOW2_CLUSTER_NORMAL:
+ {
+ /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
+ uint64_t offset = l2_entry & L2E_OFFSET_MASK;
+
+ if (flags & CHECK_OFLAG_COPIED) {
+ refcount = get_refcount(bs, offset >> s->cluster_bits);
+ if (refcount < 0) {
+ fprintf(stderr, "Can't get refcount for offset %"
+ PRIx64 ": %s\n", l2_entry, strerror(-refcount));
+ goto fail;
+ }
+ if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) {
+ fprintf(stderr, "ERROR OFLAG_COPIED: offset=%"
+ PRIx64 " refcount=%d\n", l2_entry, refcount);
res->corruptions++;
}
+ }
- /* Mark cluster as used */
- nb_csectors = ((offset >> s->csize_shift) &
- s->csize_mask) + 1;
- offset &= s->cluster_offset_mask;
- inc_refcounts(bs, res, refcount_table, refcount_table_size,
- offset & ~511, nb_csectors * 512);
- } else {
- /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
- if (check_copied) {
- 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));
- goto fail;
- }
- if ((refcount == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) {
- fprintf(stderr, "ERROR OFLAG_COPIED: offset=%"
- PRIx64 " refcount=%d\n", entry, refcount);
- res->corruptions++;
- }
+ if (flags & CHECK_FRAG_INFO) {
+ res->bfi.allocated_clusters++;
+ if (next_contiguous_offset &&
+ offset != next_contiguous_offset) {
+ res->bfi.fragmented_clusters++;
}
+ next_contiguous_offset = offset + s->cluster_size;
+ }
- /* Mark cluster as used */
- offset &= ~QCOW_OFLAG_COPIED;
- inc_refcounts(bs, res, refcount_table,refcount_table_size,
- offset, s->cluster_size);
+ /* Mark cluster as used */
+ inc_refcounts(bs, res, refcount_table,refcount_table_size,
+ offset, s->cluster_size);
- /* Correct offsets are cluster aligned */
- if (offset & (s->cluster_size - 1)) {
- fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not "
- "properly aligned; L2 entry corrupted.\n", offset);
- res->corruptions++;
- }
+ /* Correct offsets are cluster aligned */
+ if (offset & (s->cluster_size - 1)) {
+ fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not "
+ "properly aligned; L2 entry corrupted.\n", offset);
+ res->corruptions++;
}
+ break;
+ }
+
+ case QCOW2_CLUSTER_UNALLOCATED:
+ break;
+
+ default:
+ abort();
}
}
uint16_t *refcount_table,
int refcount_table_size,
int64_t l1_table_offset, int l1_size,
- int check_copied)
+ int flags)
{
BDRVQcowState *s = bs->opaque;
uint64_t *l1_table, l2_offset, l1_size2;
l2_offset = l1_table[i];
if (l2_offset) {
/* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
- if (check_copied) {
+ if (flags & CHECK_OFLAG_COPIED) {
refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED)
>> s->cluster_bits);
if (refcount < 0) {
}
/* Mark L2 table as used */
- l2_offset &= ~QCOW_OFLAG_COPIED;
+ l2_offset &= L1E_OFFSET_MASK;
inc_refcounts(bs, res, refcount_table, refcount_table_size,
l2_offset, s->cluster_size);
/* Process and check L2 entries */
ret = check_refcounts_l2(bs, res, refcount_table,
- refcount_table_size, l2_offset, check_copied);
+ refcount_table_size, l2_offset, flags);
if (ret < 0) {
goto fail;
}
* 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)
+int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
+ BdrvCheckMode fix)
{
BDRVQcowState *s = bs->opaque;
- int64_t size;
- int nb_clusters, refcount1, refcount2, i;
+ int64_t size, i, highest_cluster;
+ int nb_clusters, refcount1, refcount2;
QCowSnapshot *sn;
uint16_t *refcount_table;
int ret;
nb_clusters = size_to_clusters(s, size);
refcount_table = g_malloc0(nb_clusters * sizeof(uint16_t));
+ res->bfi.total_clusters =
+ size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE);
+
/* header */
inc_refcounts(bs, res, refcount_table, nb_clusters,
0, s->cluster_size);
/* current L1 table */
ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,
- s->l1_table_offset, s->l1_size, 1);
+ s->l1_table_offset, s->l1_size,
+ CHECK_OFLAG_COPIED | CHECK_FRAG_INFO);
if (ret < 0) {
goto fail;
}
/* Refcount blocks are cluster aligned */
if (offset & (s->cluster_size - 1)) {
- fprintf(stderr, "ERROR refcount block %d is not "
+ fprintf(stderr, "ERROR refcount block %" PRId64 " is not "
"cluster aligned; refcount table entry corrupted\n", i);
res->corruptions++;
continue;
}
if (cluster >= nb_clusters) {
- fprintf(stderr, "ERROR refcount block %d is outside image\n", i);
+ fprintf(stderr, "ERROR refcount block %" PRId64
+ " is outside image\n", i);
res->corruptions++;
continue;
}
inc_refcounts(bs, res, refcount_table, nb_clusters,
offset, s->cluster_size);
if (refcount_table[cluster] != 1) {
- fprintf(stderr, "ERROR refcount block %d refcount=%d\n",
+ fprintf(stderr, "ERROR refcount block %" PRId64
+ " refcount=%d\n",
i, refcount_table[cluster]);
res->corruptions++;
}
}
/* compare ref counts */
- for(i = 0; i < nb_clusters; i++) {
+ for (i = 0, highest_cluster = 0; i < nb_clusters; i++) {
refcount1 = get_refcount(bs, i);
if (refcount1 < 0) {
- fprintf(stderr, "Can't get refcount for cluster %d: %s\n",
+ fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n",
i, strerror(-refcount1));
res->check_errors++;
continue;
}
refcount2 = refcount_table[i];
+
+ if (refcount1 > 0 || refcount2 > 0) {
+ highest_cluster = i;
+ }
+
if (refcount1 != refcount2) {
- fprintf(stderr, "%s cluster %d refcount=%d reference=%d\n",
- refcount1 < refcount2 ? "ERROR" : "Leaked",
+
+ /* Check if we're allowed to fix the mismatch */
+ int *num_fixed = NULL;
+ if (refcount1 > refcount2 && (fix & BDRV_FIX_LEAKS)) {
+ num_fixed = &res->leaks_fixed;
+ } else if (refcount1 < refcount2 && (fix & BDRV_FIX_ERRORS)) {
+ num_fixed = &res->corruptions_fixed;
+ }
+
+ fprintf(stderr, "%s cluster %" PRId64 " refcount=%d reference=%d\n",
+ num_fixed != NULL ? "Repairing" :
+ refcount1 < refcount2 ? "ERROR" :
+ "Leaked",
i, refcount1, refcount2);
+
+ if (num_fixed) {
+ ret = update_refcount(bs, i << s->cluster_bits, 1,
+ refcount2 - refcount1,
+ QCOW2_DISCARD_ALWAYS);
+ if (ret >= 0) {
+ (*num_fixed)++;
+ continue;
+ }
+ }
+
+ /* And if we couldn't, print an error */
if (refcount1 < refcount2) {
res->corruptions++;
} else {
}
}
+ res->image_end_offset = (highest_cluster + 1) * s->cluster_size;
ret = 0;
fail:
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 chk parameter specifies exactly what checks to perform (being a bitmask
+ * of QCow2MetadataOverlap values).
+ *
+ * Returns:
+ * - 0 if writing to this offset will not affect the mentioned metadata
+ * - a positive QCow2MetadataOverlap value indicating one overlapping section
+ * - a negative value (-errno) indicating an error while performing a check,
+ * e.g. when bdrv_read failed on QCOW2_OL_INACTIVE_L2
+ */
+int qcow2_check_metadata_overlap(BlockDriverState *bs, int chk, int64_t offset,
+ int64_t size)
+{
+ BDRVQcowState *s = bs->opaque;
+ int i, j;
+
+ if (!size) {
+ return 0;
+ }
+
+ if (chk & QCOW2_OL_MAIN_HEADER) {
+ if (offset < s->cluster_size) {
+ return QCOW2_OL_MAIN_HEADER;
+ }
+ }
+
+ /* align range to test to cluster boundaries */
+ size = align_offset(offset_into_cluster(s, offset) + size, s->cluster_size);
+ offset = start_of_cluster(s, offset);
+
+ if ((chk & QCOW2_OL_ACTIVE_L1) && s->l1_size) {
+ if (overlaps_with(s->l1_table_offset, s->l1_size * sizeof(uint64_t))) {
+ return QCOW2_OL_ACTIVE_L1;
+ }
+ }
+
+ if ((chk & QCOW2_OL_REFCOUNT_TABLE) && s->refcount_table_size) {
+ if (overlaps_with(s->refcount_table_offset,
+ s->refcount_table_size * sizeof(uint64_t))) {
+ return QCOW2_OL_REFCOUNT_TABLE;
+ }
+ }
+
+ if ((chk & QCOW2_OL_SNAPSHOT_TABLE) && s->snapshots_size) {
+ if (overlaps_with(s->snapshots_offset, s->snapshots_size)) {
+ return QCOW2_OL_SNAPSHOT_TABLE;
+ }
+ }
+
+ if ((chk & QCOW2_OL_INACTIVE_L1) && s->snapshots) {
+ for (i = 0; i < s->nb_snapshots; i++) {
+ if (s->snapshots[i].l1_size &&
+ overlaps_with(s->snapshots[i].l1_table_offset,
+ s->snapshots[i].l1_size * sizeof(uint64_t))) {
+ return QCOW2_OL_INACTIVE_L1;
+ }
+ }
+ }
+
+ if ((chk & QCOW2_OL_ACTIVE_L2) && s->l1_table) {
+ for (i = 0; i < s->l1_size; i++) {
+ if ((s->l1_table[i] & L1E_OFFSET_MASK) &&
+ overlaps_with(s->l1_table[i] & L1E_OFFSET_MASK,
+ s->cluster_size)) {
+ return QCOW2_OL_ACTIVE_L2;
+ }
+ }
+ }
+
+ if ((chk & QCOW2_OL_REFCOUNT_BLOCK) && s->refcount_table) {
+ for (i = 0; i < s->refcount_table_size; i++) {
+ if ((s->refcount_table[i] & REFT_OFFSET_MASK) &&
+ overlaps_with(s->refcount_table[i] & REFT_OFFSET_MASK,
+ s->cluster_size)) {
+ return QCOW2_OL_REFCOUNT_BLOCK;
+ }
+ }
+ }
+
+ if ((chk & QCOW2_OL_INACTIVE_L2) && s->snapshots) {
+ for (i = 0; i < s->nb_snapshots; i++) {
+ uint64_t l1_ofs = s->snapshots[i].l1_table_offset;
+ uint32_t l1_sz = s->snapshots[i].l1_size;
+ uint64_t *l1 = g_malloc(l1_sz * sizeof(uint64_t));
+ int ret;
+
+ ret = bdrv_read(bs->file, l1_ofs / BDRV_SECTOR_SIZE, (uint8_t *)l1,
+ l1_sz * sizeof(uint64_t) / BDRV_SECTOR_SIZE);
+
+ if (ret < 0) {
+ g_free(l1);
+ return ret;
+ }
+
+ for (j = 0; j < l1_sz; j++) {
+ if ((l1[j] & L1E_OFFSET_MASK) &&
+ overlaps_with(l1[j] & L1E_OFFSET_MASK, s->cluster_size)) {
+ g_free(l1);
+ return QCOW2_OL_INACTIVE_L2;
+ }
+ }
+
+ g_free(l1);
+ }
+ }
+
+ return 0;
+}
+
+static const char *metadata_ol_names[] = {
+ [QCOW2_OL_MAIN_HEADER_BITNR] = "qcow2_header",
+ [QCOW2_OL_ACTIVE_L1_BITNR] = "active L1 table",
+ [QCOW2_OL_ACTIVE_L2_BITNR] = "active L2 table",
+ [QCOW2_OL_REFCOUNT_TABLE_BITNR] = "refcount table",
+ [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = "refcount block",
+ [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = "snapshot table",
+ [QCOW2_OL_INACTIVE_L1_BITNR] = "inactive L1 table",
+ [QCOW2_OL_INACTIVE_L2_BITNR] = "inactive L2 table",
+};
+
+/*
+ * First performs a check for metadata overlaps (through
+ * qcow2_check_metadata_overlap); if that fails with a negative value (error
+ * while performing a check), that value is returned. If an impending overlap
+ * is detected, the BDS will be made unusable, the qcow2 file marked corrupt
+ * and -EIO returned.
+ *
+ * Returns 0 if there were neither overlaps nor errors while checking for
+ * overlaps; or a negative value (-errno) on error.
+ */
+int qcow2_pre_write_overlap_check(BlockDriverState *bs, int chk, int64_t offset,
+ int64_t size)
+{
+ int ret = qcow2_check_metadata_overlap(bs, chk, offset, size);
+
+ if (ret < 0) {
+ return ret;
+ } else if (ret > 0) {
+ int metadata_ol_bitnr = ffs(ret) - 1;
+ char *message;
+ QObject *data;
+
+ assert(metadata_ol_bitnr < QCOW2_OL_MAX_BITNR);
+
+ fprintf(stderr, "qcow2: Preventing invalid write on metadata (overlaps "
+ "with %s); image marked as corrupt.\n",
+ metadata_ol_names[metadata_ol_bitnr]);
+ message = g_strdup_printf("Prevented %s overwrite",
+ metadata_ol_names[metadata_ol_bitnr]);
+ data = qobject_from_jsonf("{ 'device': %s, 'msg': %s, 'offset': %"
+ PRId64 ", 'size': %" PRId64 " }", bs->device_name, message,
+ offset, size);
+ monitor_protocol_event(QEVENT_BLOCK_IMAGE_CORRUPTED, data);
+ g_free(message);
+ qobject_decref(data);
+
+ qcow2_mark_corrupt(bs);
+ bs->drv = NULL; /* make BDS unusable */
+ return -EIO;
+ }
+
+ return 0;
+}
projects / qemu.git / blobdiff