#include "block/qcow2.h"
static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size);
-static int update_refcount(BlockDriverState *bs,
+static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs,
int64_t offset, int64_t length,
int addend);
+
+static int cache_refcount_updates = 0;
+
+static int write_refcount_block(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ size_t size = s->cluster_size;
+
+ if (s->refcount_block_cache_offset == 0) {
+ return 0;
+ }
+
+ BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE);
+ if (bdrv_pwrite_sync(bs->file, s->refcount_block_cache_offset,
+ s->refcount_block_cache, size) < 0)
+ {
+ return -EIO;
+ }
+
+ return 0;
+}
+
/*********************************************************/
/* refcount handling */
-int refcount_init(BlockDriverState *bs)
+int qcow2_refcount_init(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
int ret, refcount_table_size2, i;
refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t);
s->refcount_table = qemu_malloc(refcount_table_size2);
if (s->refcount_table_size > 0) {
- ret = bdrv_pread(s->hd, s->refcount_table_offset,
+ BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_LOAD);
+ ret = bdrv_pread(bs->file, s->refcount_table_offset,
s->refcount_table, refcount_table_size2);
if (ret != refcount_table_size2)
goto fail;
return -ENOMEM;
}
-void refcount_close(BlockDriverState *bs)
+void qcow2_refcount_close(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
qemu_free(s->refcount_block_cache);
{
BDRVQcowState *s = bs->opaque;
int ret;
- ret = bdrv_pread(s->hd, refcount_block_offset, s->refcount_block_cache,
+
+ if (cache_refcount_updates) {
+ ret = write_refcount_block(bs);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD);
+ ret = bdrv_pread(bs->file, refcount_block_offset, s->refcount_block_cache,
s->cluster_size);
- if (ret != s->cluster_size)
- return -EIO;
+ if (ret < 0) {
+ return ret;
+ }
+
s->refcount_block_cache_offset = refcount_block_offset;
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)
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);
return be16_to_cpu(s->refcount_block_cache[block_index]);
}
-static int grow_refcount_table(BlockDriverState *bs, int min_size)
+/*
+ * Rounds the refcount table size up to avoid growing the table for each single
+ * refcount block that is allocated.
+ */
+static unsigned int next_refcount_table_size(BDRVQcowState *s,
+ unsigned int min_size)
+{
+ unsigned int min_clusters = (min_size >> (s->cluster_bits - 3)) + 1;
+ unsigned int refcount_table_clusters =
+ MAX(1, s->refcount_table_size >> (s->cluster_bits - 3));
+
+ while (min_clusters > refcount_table_clusters) {
+ refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2;
+ }
+
+ return refcount_table_clusters << (s->cluster_bits - 3);
+}
+
+
+/* Checks if two offsets are described by the same refcount block */
+static int in_same_refcount_block(BDRVQcowState *s, uint64_t offset_a,
+ uint64_t offset_b)
+{
+ uint64_t block_a = offset_a >> (2 * s->cluster_bits - REFCOUNT_SHIFT);
+ uint64_t block_b = offset_b >> (2 * s->cluster_bits - REFCOUNT_SHIFT);
+
+ return (block_a == block_b);
+}
+
+/*
+ * Loads a refcount block. If it doesn't exist yet, it is allocated first
+ * (including growing the refcount table if needed).
+ *
+ * Returns the offset of the refcount block on success or -errno in error case
+ */
+static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index)
{
BDRVQcowState *s = bs->opaque;
- int new_table_size, new_table_size2, refcount_table_clusters, i, ret;
- uint64_t *new_table;
- int64_t table_offset;
- uint8_t data[12];
- int old_table_size;
- int64_t old_table_offset;
+ unsigned int refcount_table_index;
+ int ret;
- if (min_size <= s->refcount_table_size)
- return 0;
- /* compute new table size */
- refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
- for(;;) {
- if (refcount_table_clusters == 0) {
- refcount_table_clusters = 1;
- } else {
- refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2;
+ BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC);
+
+ /* Find the refcount block for the given cluster */
+ refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
+
+ if (refcount_table_index < s->refcount_table_size) {
+
+ uint64_t refcount_block_offset =
+ s->refcount_table[refcount_table_index];
+
+ /* If it's already there, we're done */
+ if (refcount_block_offset) {
+ if (refcount_block_offset != s->refcount_block_cache_offset) {
+ ret = load_refcount_block(bs, refcount_block_offset);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+ return refcount_block_offset;
+ }
+ }
+
+ /*
+ * If we came here, we need to allocate something. Something is at least
+ * a cluster for the new refcount block. It may also include a new refcount
+ * table if the old refcount table is too small.
+ *
+ * Note that allocating clusters here needs some special care:
+ *
+ * - We can't use the normal qcow2_alloc_clusters(), it would try to
+ * increase the refcount and very likely we would end up with an endless
+ * recursion. Instead we must place the refcount blocks in a way that
+ * they can describe them themselves.
+ *
+ * - We need to consider that at this point we are inside update_refcounts
+ * and doing the initial refcount increase. This means that some clusters
+ * have already been allocated by the caller, but their refcount isn't
+ * accurate yet. free_cluster_index tells us where this allocation ends
+ * as long as we don't overwrite it by freeing clusters.
+ *
+ * - alloc_clusters_noref and qcow2_free_clusters may load a different
+ * refcount block into the cache
+ */
+
+ if (cache_refcount_updates) {
+ ret = write_refcount_block(bs);
+ if (ret < 0) {
+ return ret;
}
- new_table_size = refcount_table_clusters << (s->cluster_bits - 3);
- if (min_size <= new_table_size)
- break;
}
+
+ /* Allocate the refcount block itself and mark it as used */
+ int64_t new_block = alloc_clusters_noref(bs, s->cluster_size);
+ if (new_block < 0) {
+ return new_block;
+ }
+
#ifdef DEBUG_ALLOC2
- printf("grow_refcount_table from %d to %d\n",
- s->refcount_table_size,
- new_table_size);
+ fprintf(stderr, "qcow2: Allocate refcount block %d for %" PRIx64
+ " at %" PRIx64 "\n",
+ refcount_table_index, cluster_index << s->cluster_bits, new_block);
#endif
- new_table_size2 = new_table_size * sizeof(uint64_t);
- new_table = qemu_mallocz(new_table_size2);
+
+ if (in_same_refcount_block(s, new_block, cluster_index << s->cluster_bits)) {
+ /* Zero the new refcount block before updating it */
+ memset(s->refcount_block_cache, 0, s->cluster_size);
+ s->refcount_block_cache_offset = new_block;
+
+ /* The block describes itself, need to update the cache */
+ int block_index = (new_block >> s->cluster_bits) &
+ ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
+ s->refcount_block_cache[block_index] = cpu_to_be16(1);
+ } else {
+ /* Described somewhere else. This can recurse at most twice before we
+ * arrive at a block that describes itself. */
+ ret = update_refcount(bs, new_block, s->cluster_size, 1);
+ if (ret < 0) {
+ goto fail_block;
+ }
+
+ /* Initialize the new refcount block only after updating its refcount,
+ * update_refcount uses the refcount cache itself */
+ memset(s->refcount_block_cache, 0, s->cluster_size);
+ s->refcount_block_cache_offset = new_block;
+ }
+
+ /* Now the new refcount block needs to be written to disk */
+ BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE);
+ ret = bdrv_pwrite_sync(bs->file, new_block, s->refcount_block_cache,
+ s->cluster_size);
+ if (ret < 0) {
+ goto fail_block;
+ }
+
+ /* If the refcount table is big enough, just hook the block up there */
+ if (refcount_table_index < s->refcount_table_size) {
+ uint64_t data64 = cpu_to_be64(new_block);
+ BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_HOOKUP);
+ ret = bdrv_pwrite_sync(bs->file,
+ s->refcount_table_offset + refcount_table_index * sizeof(uint64_t),
+ &data64, sizeof(data64));
+ if (ret < 0) {
+ goto fail_block;
+ }
+
+ s->refcount_table[refcount_table_index] = new_block;
+ return new_block;
+ }
+
+ /*
+ * If we come here, we need to grow the refcount table. Again, a new
+ * refcount table needs some space and we can't simply allocate to avoid
+ * endless recursion.
+ *
+ * Therefore let's grab new refcount blocks at the end of the image, which
+ * will describe themselves and the new refcount table. This way we can
+ * reference them only in the new table and do the switch to the new
+ * refcount table at once without producing an inconsistent state in
+ * between.
+ */
+ BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_GROW);
+
+ /* Calculate the number of refcount blocks needed so far */
+ uint64_t refcount_block_clusters = 1 << (s->cluster_bits - REFCOUNT_SHIFT);
+ uint64_t blocks_used = (s->free_cluster_index +
+ refcount_block_clusters - 1) / refcount_block_clusters;
+
+ /* And now we need at least one block more for the new metadata */
+ uint64_t table_size = next_refcount_table_size(s, blocks_used + 1);
+ uint64_t last_table_size;
+ uint64_t blocks_clusters;
+ do {
+ uint64_t table_clusters = size_to_clusters(s, table_size);
+ blocks_clusters = 1 +
+ ((table_clusters + refcount_block_clusters - 1)
+ / refcount_block_clusters);
+ uint64_t meta_clusters = table_clusters + blocks_clusters;
+
+ last_table_size = table_size;
+ table_size = next_refcount_table_size(s, blocks_used +
+ ((meta_clusters + refcount_block_clusters - 1)
+ / refcount_block_clusters));
+
+ } while (last_table_size != table_size);
+
+#ifdef DEBUG_ALLOC2
+ fprintf(stderr, "qcow2: Grow refcount table %" PRId32 " => %" PRId64 "\n",
+ s->refcount_table_size, table_size);
+#endif
+
+ /* Create the new refcount table and blocks */
+ uint64_t meta_offset = (blocks_used * refcount_block_clusters) *
+ s->cluster_size;
+ uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size;
+ uint16_t *new_blocks = qemu_mallocz(blocks_clusters * s->cluster_size);
+ uint64_t *new_table = qemu_mallocz(table_size * sizeof(uint64_t));
+
+ assert(meta_offset >= (s->free_cluster_index * s->cluster_size));
+
+ /* Fill the new refcount table */
memcpy(new_table, s->refcount_table,
- s->refcount_table_size * sizeof(uint64_t));
- for(i = 0; i < s->refcount_table_size; i++)
+ s->refcount_table_size * sizeof(uint64_t));
+ new_table[refcount_table_index] = new_block;
+
+ int i;
+ for (i = 0; i < blocks_clusters; i++) {
+ new_table[blocks_used + i] = meta_offset + (i * s->cluster_size);
+ }
+
+ /* Fill the refcount blocks */
+ uint64_t table_clusters = size_to_clusters(s, table_size * sizeof(uint64_t));
+ int block = 0;
+ for (i = 0; i < table_clusters + blocks_clusters; i++) {
+ new_blocks[block++] = cpu_to_be16(1);
+ }
+
+ /* Write refcount blocks to disk */
+ BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS);
+ ret = bdrv_pwrite_sync(bs->file, meta_offset, new_blocks,
+ blocks_clusters * s->cluster_size);
+ qemu_free(new_blocks);
+ if (ret < 0) {
+ goto fail_table;
+ }
+
+ /* Write refcount table to disk */
+ for(i = 0; i < table_size; i++) {
cpu_to_be64s(&new_table[i]);
- /* Note: we cannot update the refcount now to avoid recursion */
- table_offset = alloc_clusters_noref(bs, new_table_size2);
- ret = bdrv_pwrite(s->hd, table_offset, new_table, new_table_size2);
- if (ret != new_table_size2)
- goto fail;
- for(i = 0; i < s->refcount_table_size; i++)
- be64_to_cpus(&new_table[i]);
+ }
+ BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE);
+ ret = bdrv_pwrite_sync(bs->file, table_offset, new_table,
+ table_size * sizeof(uint64_t));
+ if (ret < 0) {
+ goto fail_table;
+ }
+
+ for(i = 0; i < table_size; i++) {
+ cpu_to_be64s(&new_table[i]);
+ }
+
+ /* Hook up the new refcount table in the qcow2 header */
+ uint8_t data[12];
cpu_to_be64w((uint64_t*)data, table_offset);
- cpu_to_be32w((uint32_t*)(data + 8), refcount_table_clusters);
- if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset),
- data, sizeof(data)) != sizeof(data))
- goto fail;
+ cpu_to_be32w((uint32_t*)(data + 8), table_clusters);
+ BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE);
+ ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, refcount_table_offset),
+ data, sizeof(data));
+ if (ret < 0) {
+ goto fail_table;
+ }
+
+ /* And switch it in memory */
+ uint64_t old_table_offset = s->refcount_table_offset;
+ uint64_t old_table_size = s->refcount_table_size;
+
qemu_free(s->refcount_table);
- old_table_offset = s->refcount_table_offset;
- old_table_size = s->refcount_table_size;
s->refcount_table = new_table;
- s->refcount_table_size = new_table_size;
+ s->refcount_table_size = table_size;
s->refcount_table_offset = table_offset;
- update_refcount(bs, table_offset, new_table_size2, 1);
- free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t));
- return 0;
- fail:
- free_clusters(bs, table_offset, new_table_size2);
+ /* 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));
+ s->free_cluster_index = old_free_cluster_index;
+
+ ret = load_refcount_block(bs, new_block);
+ if (ret < 0) {
+ goto fail_block;
+ }
+
+ return new_block;
+
+fail_table:
qemu_free(new_table);
- return -EIO;
+fail_block:
+ s->refcount_block_cache_offset = 0;
+ return ret;
}
-
-static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index)
+#define REFCOUNTS_PER_SECTOR (512 >> REFCOUNT_SHIFT)
+static int write_refcount_block_entries(BlockDriverState *bs,
+ int64_t refcount_block_offset, int first_index, int last_index)
{
BDRVQcowState *s = bs->opaque;
- int64_t offset, refcount_block_offset;
- int ret, refcount_table_index;
- uint64_t data64;
+ size_t size;
+ int ret;
- /* Find L1 index and grow refcount table if needed */
- refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
- if (refcount_table_index >= s->refcount_table_size) {
- ret = grow_refcount_table(bs, refcount_table_index + 1);
- if (ret < 0)
- return ret;
+ if (cache_refcount_updates) {
+ return 0;
}
- /* Load or allocate the refcount block */
- refcount_block_offset = s->refcount_table[refcount_table_index];
- if (!refcount_block_offset) {
- /* create a new refcount block */
- /* Note: we cannot update the refcount now to avoid recursion */
- offset = alloc_clusters_noref(bs, s->cluster_size);
- memset(s->refcount_block_cache, 0, s->cluster_size);
- ret = bdrv_pwrite(s->hd, offset, s->refcount_block_cache, s->cluster_size);
- if (ret != s->cluster_size)
- return -EINVAL;
- s->refcount_table[refcount_table_index] = offset;
- data64 = cpu_to_be64(offset);
- ret = bdrv_pwrite(s->hd, s->refcount_table_offset +
- refcount_table_index * sizeof(uint64_t),
- &data64, sizeof(data64));
- if (ret != sizeof(data64))
- return -EINVAL;
-
- refcount_block_offset = offset;
- s->refcount_block_cache_offset = offset;
- update_refcount(bs, offset, s->cluster_size, 1);
- } else {
- if (refcount_block_offset != s->refcount_block_cache_offset) {
- if (load_refcount_block(bs, refcount_block_offset) < 0)
- return -EIO;
- }
+ if (first_index < 0) {
+ return 0;
}
- return refcount_block_offset;
+ first_index &= ~(REFCOUNTS_PER_SECTOR - 1);
+ last_index = (last_index + REFCOUNTS_PER_SECTOR)
+ & ~(REFCOUNTS_PER_SECTOR - 1);
+
+ size = (last_index - first_index) << REFCOUNT_SHIFT;
+
+ BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE_PART);
+ ret = bdrv_pwrite_sync(bs->file,
+ refcount_block_offset + (first_index << REFCOUNT_SHIFT),
+ &s->refcount_block_cache[first_index], size);
+ if (ret < 0) {
+ return ret;
+ }
+
+ return 0;
}
/* XXX: cache several refcount block clusters ? */
-static int update_refcount(BlockDriverState *bs,
- int64_t offset, int64_t length,
- int addend)
+static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs,
+ int64_t offset, int64_t length, int addend)
{
BDRVQcowState *s = bs->opaque;
int64_t start, last, cluster_offset;
int64_t refcount_block_offset = 0;
int64_t table_index = -1, old_table_index;
int first_index = -1, last_index = -1;
+ int ret;
#ifdef DEBUG_ALLOC2
- printf("update_refcount: offset=%lld size=%lld addend=%d\n",
+ printf("update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n",
offset, length, addend);
#endif
- if (length <= 0)
+ if (length < 0) {
return -EINVAL;
+ } else if (length == 0) {
+ return 0;
+ }
+
start = offset & ~(s->cluster_size - 1);
last = (offset + length - 1) & ~(s->cluster_size - 1);
for(cluster_offset = start; cluster_offset <= last;
{
int block_index, refcount;
int64_t cluster_index = cluster_offset >> s->cluster_bits;
+ int64_t new_block;
/* Only write refcount block to disk when we are done with it */
old_table_index = table_index;
table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
if ((old_table_index >= 0) && (table_index != old_table_index)) {
- size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT;
- if (bdrv_pwrite(s->hd,
- refcount_block_offset + (first_index << REFCOUNT_SHIFT),
- &s->refcount_block_cache[first_index], size) != size)
- {
- return -EIO;
+
+ ret = write_refcount_block_entries(bs, refcount_block_offset,
+ first_index, last_index);
+ if (ret < 0) {
+ return ret;
}
first_index = -1;
}
/* Load the refcount block and allocate it if needed */
- refcount_block_offset = alloc_refcount_block(bs, cluster_index);
- if (refcount_block_offset < 0) {
- return refcount_block_offset;
+ new_block = alloc_refcount_block(bs, cluster_index);
+ if (new_block < 0) {
+ ret = new_block;
+ goto fail;
}
+ refcount_block_offset = new_block;
/* we can update the count and save it */
block_index = cluster_index &
refcount = be16_to_cpu(s->refcount_block_cache[block_index]);
refcount += addend;
- if (refcount < 0 || refcount > 0xffff)
- return -EINVAL;
+ if (refcount < 0 || refcount > 0xffff) {
+ ret = -EINVAL;
+ goto fail;
+ }
if (refcount == 0 && cluster_index < s->free_cluster_index) {
s->free_cluster_index = cluster_index;
}
s->refcount_block_cache[block_index] = cpu_to_be16(refcount);
}
+ ret = 0;
+fail:
+
/* Write last changed block to disk */
if (refcount_block_offset != 0) {
- size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT;
- if (bdrv_pwrite(s->hd,
- refcount_block_offset + (first_index << REFCOUNT_SHIFT),
- &s->refcount_block_cache[first_index], size) != size)
- {
- return -EIO;
+ int wret;
+ wret = write_refcount_block_entries(bs, refcount_block_offset,
+ first_index, last_index);
+ if (wret < 0) {
+ return ret < 0 ? ret : wret;
}
}
- return 0;
+ /*
+ * 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);
+ }
+
+ 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)
static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size)
{
BDRVQcowState *s = bs->opaque;
- int i, nb_clusters;
+ int i, nb_clusters, refcount;
nb_clusters = size_to_clusters(s, size);
retry:
for(i = 0; i < nb_clusters; i++) {
- int64_t i = s->free_cluster_index++;
- if (get_refcount(bs, i) != 0)
+ int64_t next_cluster_index = s->free_cluster_index++;
+ refcount = get_refcount(bs, next_cluster_index);
+
+ if (refcount < 0) {
+ return refcount;
+ } else if (refcount != 0) {
goto retry;
+ }
}
#ifdef DEBUG_ALLOC2
- printf("alloc_clusters: size=%lld -> %lld\n",
+ printf("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 alloc_clusters(BlockDriverState *bs, int64_t size)
+int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size)
{
int64_t offset;
+ int ret;
+ BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
offset = alloc_clusters_noref(bs, size);
- update_refcount(bs, offset, size, 1);
+ if (offset < 0) {
+ return offset;
+ }
+
+ ret = update_refcount(bs, offset, size, 1);
+ if (ret < 0) {
+ return ret;
+ }
return offset;
}
/* only used to allocate compressed sectors. We try to allocate
contiguous sectors. size must be <= cluster_size */
-int64_t alloc_bytes(BlockDriverState *bs, int size)
+int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size)
{
BDRVQcowState *s = bs->opaque;
int64_t offset, cluster_offset;
int free_in_cluster;
+ BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES);
assert(size > 0 && size <= s->cluster_size);
if (s->free_byte_offset == 0) {
- s->free_byte_offset = alloc_clusters(bs, s->cluster_size);
+ s->free_byte_offset = qcow2_alloc_clusters(bs, s->cluster_size);
+ if (s->free_byte_offset < 0) {
+ return s->free_byte_offset;
+ }
}
redo:
free_in_cluster = s->cluster_size -
if ((offset & (s->cluster_size - 1)) != 0)
update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
} else {
- offset = alloc_clusters(bs, s->cluster_size);
+ offset = qcow2_alloc_clusters(bs, s->cluster_size);
+ if (offset < 0) {
+ return offset;
+ }
cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1);
if ((cluster_offset + s->cluster_size) == offset) {
/* we are lucky: contiguous data */
return offset;
}
-void free_clusters(BlockDriverState *bs,
+void qcow2_free_clusters(BlockDriverState *bs,
int64_t offset, int64_t size)
{
- update_refcount(bs, offset, size, -1);
+ int ret;
+
+ BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_FREE);
+ ret = update_refcount(bs, offset, size, -1);
+ if (ret < 0) {
+ fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret));
+ /* TODO Remember the clusters to free them later and avoid leaking */
+ }
}
/*
*
*/
-void free_any_clusters(BlockDriverState *bs,
+void qcow2_free_any_clusters(BlockDriverState *bs,
uint64_t cluster_offset, int nb_clusters)
{
BDRVQcowState *s = bs->opaque;
int nb_csectors;
nb_csectors = ((cluster_offset >> s->csize_shift) &
s->csize_mask) + 1;
- free_clusters(bs, (cluster_offset & s->cluster_offset_mask) & ~511,
- nb_csectors * 512);
+ qcow2_free_clusters(bs,
+ (cluster_offset & s->cluster_offset_mask) & ~511,
+ nb_csectors * 512);
return;
}
- free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits);
+ qcow2_free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits);
return;
}
-void create_refcount_update(QCowCreateState *s, int64_t offset, int64_t size)
+void qcow2_create_refcount_update(QCowCreateState *s, int64_t offset,
+ int64_t size)
{
int refcount;
int64_t start, last, cluster_offset;
}
/* update the refcounts of snapshots and the copied flag */
-int update_snapshot_refcount(BlockDriverState *bs,
- int64_t l1_table_offset,
- int l1_size,
- int addend)
+int qcow2_update_snapshot_refcount(BlockDriverState *bs,
+ int64_t l1_table_offset, int l1_size, int addend)
{
BDRVQcowState *s = bs->opaque;
uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated;
int64_t old_offset, old_l2_offset;
int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount;
- l2_cache_reset(bs);
+ qcow2_l2_cache_reset(bs);
+ cache_refcount_updates = 1;
l2_table = NULL;
l1_table = NULL;
l1_size2 = l1_size * sizeof(uint64_t);
- l1_allocated = 0;
if (l1_table_offset != s->l1_table_offset) {
- l1_table = qemu_malloc(l1_size2);
+ if (l1_size2 != 0) {
+ l1_table = qemu_mallocz(align_offset(l1_size2, 512));
+ } else {
+ l1_table = NULL;
+ }
l1_allocated = 1;
- if (bdrv_pread(s->hd, l1_table_offset,
+ if (bdrv_pread(bs->file, l1_table_offset,
l1_table, l1_size2) != l1_size2)
goto fail;
for(i = 0;i < l1_size; i++)
old_l2_offset = l2_offset;
l2_offset &= ~QCOW_OFLAG_COPIED;
l2_modified = 0;
- if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
+ if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size)
goto fail;
for(j = 0; j < s->l2_size; j++) {
offset = be64_to_cpu(l2_table[j]);
if (offset & QCOW_OFLAG_COMPRESSED) {
nb_csectors = ((offset >> s->csize_shift) &
s->csize_mask) + 1;
- if (addend != 0)
- update_refcount(bs, (offset & s->cluster_offset_mask) & ~511,
- nb_csectors * 512, addend);
+ if (addend != 0) {
+ int ret;
+ ret = update_refcount(bs,
+ (offset & s->cluster_offset_mask) & ~511,
+ nb_csectors * 512, addend);
+ if (ret < 0) {
+ goto fail;
+ }
+ }
/* compressed clusters are never modified */
refcount = 2;
} else {
} else {
refcount = get_refcount(bs, offset >> s->cluster_bits);
}
+
+ if (refcount < 0) {
+ goto fail;
+ }
}
if (refcount == 1) {
}
}
if (l2_modified) {
- if (bdrv_pwrite(s->hd,
- l2_offset, l2_table, l2_size) != l2_size)
+ if (bdrv_pwrite_sync(bs->file,
+ l2_offset, l2_table, l2_size) < 0)
goto fail;
}
} 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) {
if (l1_modified) {
for(i = 0; i < l1_size; i++)
cpu_to_be64s(&l1_table[i]);
- if (bdrv_pwrite(s->hd, l1_table_offset, l1_table,
- l1_size2) != l1_size2)
+ if (bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table,
+ l1_size2) < 0)
goto fail;
for(i = 0; i < l1_size; i++)
be64_to_cpus(&l1_table[i]);
if (l1_allocated)
qemu_free(l1_table);
qemu_free(l2_table);
+ cache_refcount_updates = 0;
+ write_refcount_block(bs);
return 0;
fail:
if (l1_allocated)
qemu_free(l1_table);
qemu_free(l2_table);
+ cache_refcount_updates = 0;
+ write_refcount_block(bs);
return -EIO;
}
* This is used to construct a temporary refcount table out of L1 and L2 tables
* which can be compared the the refcount table saved in the image.
*
- * Returns the number of errors in the image that were found
+ * Modifies the number of errors in res.
*/
-static int inc_refcounts(BlockDriverState *bs,
+static void inc_refcounts(BlockDriverState *bs,
+ BdrvCheckResult *res,
uint16_t *refcount_table,
int refcount_table_size,
int64_t offset, int64_t size)
BDRVQcowState *s = bs->opaque;
int64_t start, last, cluster_offset;
int k;
- int errors = 0;
if (size <= 0)
- return 0;
+ return;
start = offset & ~(s->cluster_size - 1);
last = (offset + size - 1) & ~(s->cluster_size - 1);
for(cluster_offset = start; cluster_offset <= last;
cluster_offset += s->cluster_size) {
k = cluster_offset >> s->cluster_bits;
- if (k < 0 || k >= refcount_table_size) {
+ if (k < 0) {
fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n",
cluster_offset);
- errors++;
+ res->corruptions++;
+ } else if (k >= refcount_table_size) {
+ fprintf(stderr, "Warning: cluster offset=0x%" PRIx64 " is after "
+ "the end of the image file, can't properly check refcounts.\n",
+ cluster_offset);
+ res->check_errors++;
} else {
if (++refcount_table[k] == 0) {
fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64
"\n", cluster_offset);
- errors++;
+ res->corruptions++;
}
}
}
-
- return errors;
}
/*
* Returns the number of errors found by the checks or -errno if an internal
* error occurred.
*/
-static int check_refcounts_l2(BlockDriverState *bs,
+static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset,
int check_copied)
{
BDRVQcowState *s = bs->opaque;
uint64_t *l2_table, offset;
int i, l2_size, nb_csectors, refcount;
- int errors = 0;
/* Read L2 table from disk */
l2_size = s->l2_size * sizeof(uint64_t);
l2_table = qemu_malloc(l2_size);
- if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
+ if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size)
goto fail;
/* Do the actual checks */
"copied flag must never be set for compressed "
"clusters\n", offset >> s->cluster_bits);
offset &= ~QCOW_OFLAG_COPIED;
- errors++;
+ res->corruptions++;
}
/* Mark cluster as used */
nb_csectors = ((offset >> s->csize_shift) &
s->csize_mask) + 1;
offset &= s->cluster_offset_mask;
- errors += inc_refcounts(bs, refcount_table,
- refcount_table_size,
- offset & ~511, nb_csectors * 512);
+ 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);
- errors++;
+ res->corruptions++;
}
}
/* Mark cluster as used */
offset &= ~QCOW_OFLAG_COPIED;
- errors += inc_refcounts(bs, refcount_table,
- refcount_table_size,
- offset, s->cluster_size);
+ 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);
- errors++;
+ res->corruptions++;
}
}
}
}
qemu_free(l2_table);
- return errors;
+ return 0;
fail:
- fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
+ fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n");
qemu_free(l2_table);
return -EIO;
}
* error occurred.
*/
static int check_refcounts_l1(BlockDriverState *bs,
+ BdrvCheckResult *res,
uint16_t *refcount_table,
int refcount_table_size,
int64_t l1_table_offset, int l1_size,
BDRVQcowState *s = bs->opaque;
uint64_t *l1_table, l2_offset, l1_size2;
int i, refcount, ret;
- int errors = 0;
l1_size2 = l1_size * sizeof(uint64_t);
/* Mark L1 table as used */
- errors += inc_refcounts(bs, refcount_table, refcount_table_size,
- l1_table_offset, l1_size2);
+ inc_refcounts(bs, res, refcount_table, refcount_table_size,
+ l1_table_offset, l1_size2);
/* Read L1 table entries from disk */
- l1_table = qemu_malloc(l1_size2);
- if (bdrv_pread(s->hd, l1_table_offset,
- l1_table, l1_size2) != l1_size2)
- goto fail;
- for(i = 0;i < l1_size; i++)
- be64_to_cpus(&l1_table[i]);
+ if (l1_size2 == 0) {
+ l1_table = NULL;
+ } else {
+ l1_table = qemu_malloc(l1_size2);
+ if (bdrv_pread(bs->file, l1_table_offset,
+ l1_table, l1_size2) != l1_size2)
+ goto fail;
+ for(i = 0;i < l1_size; i++)
+ be64_to_cpus(&l1_table[i]);
+ }
/* Do the actual checks */
for(i = 0; i < l1_size; i++) {
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));
+ goto fail;
+ }
if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) {
fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64
" refcount=%d\n", l2_offset, refcount);
- errors++;
+ res->corruptions++;
}
}
/* Mark L2 table as used */
l2_offset &= ~QCOW_OFLAG_COPIED;
- errors += inc_refcounts(bs, refcount_table,
- refcount_table_size,
- l2_offset,
- s->cluster_size);
+ inc_refcounts(bs, res, refcount_table, refcount_table_size,
+ l2_offset, s->cluster_size);
/* L2 tables are cluster aligned */
if (l2_offset & (s->cluster_size - 1)) {
fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not "
"cluster aligned; L1 entry corrupted\n", l2_offset);
- errors++;
+ res->corruptions++;
}
/* Process and check L2 entries */
- ret = check_refcounts_l2(bs, refcount_table, refcount_table_size,
- l2_offset, check_copied);
+ ret = check_refcounts_l2(bs, res, refcount_table,
+ refcount_table_size, l2_offset, check_copied);
if (ret < 0) {
goto fail;
}
- errors += ret;
}
}
qemu_free(l1_table);
- return errors;
+ return 0;
fail:
fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
+ res->check_errors++;
qemu_free(l1_table);
return -EIO;
}
* 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 occured.
*/
-int check_refcounts(BlockDriverState *bs)
+int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res)
{
BDRVQcowState *s = bs->opaque;
int64_t size;
int nb_clusters, refcount1, refcount2, i;
QCowSnapshot *sn;
uint16_t *refcount_table;
- int ret, errors = 0;
+ int ret;
- size = bdrv_getlength(s->hd);
+ size = bdrv_getlength(bs->file);
nb_clusters = size_to_clusters(s, size);
refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t));
/* header */
- errors += inc_refcounts(bs, refcount_table, nb_clusters,
- 0, s->cluster_size);
+ inc_refcounts(bs, res, refcount_table, nb_clusters,
+ 0, s->cluster_size);
/* current L1 table */
- ret = check_refcounts_l1(bs, refcount_table, nb_clusters,
+ ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,
s->l1_table_offset, s->l1_size, 1);
if (ret < 0) {
return ret;
}
- errors += ret;
/* snapshots */
for(i = 0; i < s->nb_snapshots; i++) {
sn = s->snapshots + i;
- check_refcounts_l1(bs, refcount_table, nb_clusters,
- sn->l1_table_offset, sn->l1_size, 0);
+ ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,
+ sn->l1_table_offset, sn->l1_size, 0);
+ if (ret < 0) {
+ return ret;
+ }
}
- errors += inc_refcounts(bs, refcount_table, nb_clusters,
- s->snapshots_offset, s->snapshots_size);
+ inc_refcounts(bs, res, refcount_table, nb_clusters,
+ s->snapshots_offset, s->snapshots_size);
/* refcount data */
- errors += inc_refcounts(bs, refcount_table, nb_clusters,
- s->refcount_table_offset,
- s->refcount_table_size * sizeof(uint64_t));
+ inc_refcounts(bs, res, refcount_table, nb_clusters,
+ s->refcount_table_offset,
+ s->refcount_table_size * sizeof(uint64_t));
+
for(i = 0; i < s->refcount_table_size; i++) {
- int64_t offset;
+ uint64_t offset, cluster;
offset = s->refcount_table[i];
+ cluster = offset >> s->cluster_bits;
+
+ /* Refcount blocks are cluster aligned */
+ if (offset & (s->cluster_size - 1)) {
+ fprintf(stderr, "ERROR refcount block %d 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);
+ res->corruptions++;
+ continue;
+ }
+
if (offset != 0) {
- errors += inc_refcounts(bs, refcount_table, nb_clusters,
- offset, s->cluster_size);
+ 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",
+ i, refcount_table[cluster]);
+ res->corruptions++;
+ }
}
}
/* 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));
+ res->check_errors++;
+ continue;
+ }
+
refcount2 = refcount_table[i];
if (refcount1 != refcount2) {
- fprintf(stderr, "ERROR cluster %d refcount=%d reference=%d\n",
+ fprintf(stderr, "%s cluster %d refcount=%d reference=%d\n",
+ refcount1 < refcount2 ? "ERROR" : "Leaked",
i, refcount1, refcount2);
- errors++;
+ if (refcount1 < refcount2) {
+ res->corruptions++;
+ } else {
+ res->leaks++;
+ }
}
}
qemu_free(refcount_table);
- return errors;
+ return 0;
}
projects / qemu.git / blobdiff