//#define DEBUG_ALLOC
//#define DEBUG_ALLOC2
+//#define DEBUG_EXT
#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
#define QCOW_VERSION 2
#define QCOW_CRYPT_NONE 0
#define QCOW_CRYPT_AES 1
+#define QCOW_MAX_CRYPT_CLUSTERS 32
+
/* indicate that the refcount of the referenced cluster is exactly one. */
#define QCOW_OFLAG_COPIED (1LL << 63)
/* indicate that the cluster is compressed (they never have the copied flag) */
#define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
-#ifndef offsetof
-#define offsetof(type, field) ((size_t) &((type *)0)->field)
-#endif
-
typedef struct QCowHeader {
uint32_t magic;
uint32_t version;
uint64_t snapshots_offset;
} QCowHeader;
+
+typedef struct {
+ uint32_t magic;
+ uint32_t len;
+} QCowExtension;
+#define QCOW_EXT_MAGIC_END 0
+#define QCOW_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
+
+
typedef struct __attribute__((packed)) QCowSnapshotHeader {
/* header is 8 byte aligned */
uint64_t l1_table_offset;
static int64_t alloc_bytes(BlockDriverState *bs, int size);
static void free_clusters(BlockDriverState *bs,
int64_t offset, int64_t size);
-#ifdef DEBUG_ALLOC
-static void check_refcounts(BlockDriverState *bs);
-#endif
+static int check_refcounts(BlockDriverState *bs);
static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
{
return 0;
}
+
+/*
+ * read qcow2 extension and fill bs
+ * start reading from start_offset
+ * finish reading upon magic of value 0 or when end_offset reached
+ * unknown magic is skipped (future extension this version knows nothing about)
+ * return 0 upon success, non-0 otherwise
+ */
+static int qcow_read_extensions(BlockDriverState *bs, uint64_t start_offset,
+ uint64_t end_offset)
+{
+ BDRVQcowState *s = bs->opaque;
+ QCowExtension ext;
+ uint64_t offset;
+
+#ifdef DEBUG_EXT
+ printf("qcow_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
+#endif
+ offset = start_offset;
+ while (offset < end_offset) {
+
+#ifdef DEBUG_EXT
+ /* Sanity check */
+ if (offset > s->cluster_size)
+ printf("qcow_handle_extension: suspicious offset %lu\n", offset);
+
+ printf("attemting to read extended header in offset %lu\n", offset);
+#endif
+
+ if (bdrv_pread(s->hd, offset, &ext, sizeof(ext)) != sizeof(ext)) {
+ fprintf(stderr, "qcow_handle_extension: ERROR: pread fail from offset %llu\n",
+ (unsigned long long)offset);
+ return 1;
+ }
+ be32_to_cpus(&ext.magic);
+ be32_to_cpus(&ext.len);
+ offset += sizeof(ext);
+#ifdef DEBUG_EXT
+ printf("ext.magic = 0x%x\n", ext.magic);
+#endif
+ switch (ext.magic) {
+ case QCOW_EXT_MAGIC_END:
+ return 0;
+
+ case QCOW_EXT_MAGIC_BACKING_FORMAT:
+ if (ext.len >= sizeof(bs->backing_format)) {
+ fprintf(stderr, "ERROR: ext_backing_format: len=%u too large"
+ " (>=%zu)\n",
+ ext.len, sizeof(bs->backing_format));
+ return 2;
+ }
+ if (bdrv_pread(s->hd, offset , bs->backing_format,
+ ext.len) != ext.len)
+ return 3;
+ bs->backing_format[ext.len] = '\0';
+#ifdef DEBUG_EXT
+ printf("Qcow2: Got format extension %s\n", bs->backing_format);
+#endif
+ offset += ((ext.len + 7) & ~7);
+ break;
+
+ default:
+ /* unknown magic -- just skip it */
+ offset += ((ext.len + 7) & ~7);
+ break;
+ }
+ }
+
+ return 0;
+}
+
+
static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
{
BDRVQcowState *s = bs->opaque;
int len, i, shift, ret;
QCowHeader header;
+ uint64_t ext_end;
+ /* Performance is terrible right now with cache=writethrough due mainly
+ * to reference count updates. If the user does not explicitly specify
+ * a caching type, force to writeback caching.
+ */
+ if ((flags & BDRV_O_CACHE_DEF)) {
+ flags |= BDRV_O_CACHE_WB;
+ flags &= ~BDRV_O_CACHE_DEF;
+ }
ret = bdrv_file_open(&s->hd, filename, flags);
if (ret < 0)
return ret;
goto fail;
s->l1_table_offset = header.l1_table_offset;
s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
- if (!s->l1_table)
- goto fail;
if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
s->l1_size * sizeof(uint64_t))
goto fail;
}
/* alloc L2 cache */
s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
- if (!s->l2_cache)
- goto fail;
s->cluster_cache = qemu_malloc(s->cluster_size);
- if (!s->cluster_cache)
- goto fail;
/* one more sector for decompressed data alignment */
- s->cluster_data = qemu_malloc(s->cluster_size + 512);
- if (!s->cluster_data)
- goto fail;
+ s->cluster_data = qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
+ + 512);
s->cluster_cache_offset = -1;
if (refcount_init(bs) < 0)
goto fail;
+ /* read qcow2 extensions */
+ if (header.backing_file_offset)
+ ext_end = header.backing_file_offset;
+ else
+ ext_end = s->cluster_size;
+ if (qcow_read_extensions(bs, sizeof(header), ext_end))
+ goto fail;
+
/* read the backing file name */
if (header.backing_file_offset != 0) {
len = header.backing_file_size;
int new_l1_size, new_l1_size2, ret, i;
uint64_t *new_l1_table;
uint64_t new_l1_table_offset;
- uint64_t data64;
- uint32_t data32;
+ uint8_t data[12];
new_l1_size = s->l1_size;
if (min_size <= new_l1_size)
new_l1_size2 = sizeof(uint64_t) * new_l1_size;
new_l1_table = qemu_mallocz(new_l1_size2);
- if (!new_l1_table)
- return -ENOMEM;
memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
/* write new table (align to cluster) */
new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
/* set new table */
- data64 = cpu_to_be64(new_l1_table_offset);
- if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_table_offset),
- &data64, sizeof(data64)) != sizeof(data64))
- goto fail;
- data32 = cpu_to_be32(new_l1_size);
- if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_size),
- &data32, sizeof(data32)) != sizeof(data32))
+ cpu_to_be32w((uint32_t*)data, new_l1_size);
+ cpu_to_be64w((uint64_t*)(data + 4), new_l1_table_offset);
+ if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_size), data,
+ sizeof(data)) != sizeof(data))
goto fail;
qemu_free(s->l1_table);
free_clusters(bs, s->l1_table_offset, s->l1_size * sizeof(uint64_t));
return -EIO;
}
-/* 'allocate' is:
+/*
+ * seek_l2_table
*
- * 0 not to allocate.
+ * seek l2_offset in the l2_cache table
+ * if not found, return NULL,
+ * if found,
+ * increments the l2 cache hit count of the entry,
+ * if counter overflow, divide by two all counters
+ * return the pointer to the l2 cache entry
*
- * 1 to allocate a normal cluster (for sector indexes 'n_start' to
- * 'n_end')
+ */
+
+static uint64_t *seek_l2_table(BDRVQcowState *s, uint64_t l2_offset)
+{
+ int i, j;
+
+ for(i = 0; i < L2_CACHE_SIZE; i++) {
+ if (l2_offset == s->l2_cache_offsets[i]) {
+ /* increment the hit count */
+ if (++s->l2_cache_counts[i] == 0xffffffff) {
+ for(j = 0; j < L2_CACHE_SIZE; j++) {
+ s->l2_cache_counts[j] >>= 1;
+ }
+ }
+ return s->l2_cache + (i << s->l2_bits);
+ }
+ }
+ return NULL;
+}
+
+/*
+ * l2_load
*
- * 2 to allocate a compressed cluster of size
- * 'compressed_size'. 'compressed_size' must be > 0 and <
- * cluster_size
+ * Loads a L2 table into memory. If the table is in the cache, the cache
+ * is used; otherwise the L2 table is loaded from the image file.
*
- * return 0 if not allocated.
+ * Returns a pointer to the L2 table on success, or NULL if the read from
+ * the image file failed.
*/
-static uint64_t get_cluster_offset(BlockDriverState *bs,
- uint64_t offset, int allocate,
- int compressed_size,
- int n_start, int n_end)
+
+static uint64_t *l2_load(BlockDriverState *bs, uint64_t l2_offset)
{
BDRVQcowState *s = bs->opaque;
- int min_index, i, j, l1_index, l2_index, ret;
- uint64_t l2_offset, *l2_table, cluster_offset, tmp, old_l2_offset;
+ int min_index;
+ uint64_t *l2_table;
- l1_index = offset >> (s->l2_bits + s->cluster_bits);
- if (l1_index >= s->l1_size) {
- /* outside l1 table is allowed: we grow the table if needed */
- if (!allocate)
- return 0;
- if (grow_l1_table(bs, l1_index + 1) < 0)
- return 0;
- }
- l2_offset = s->l1_table[l1_index];
- if (!l2_offset) {
- if (!allocate)
- return 0;
- l2_allocate:
- old_l2_offset = l2_offset;
- /* allocate a new l2 entry */
- l2_offset = alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
- /* update the L1 entry */
- s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
- tmp = cpu_to_be64(l2_offset | QCOW_OFLAG_COPIED);
- if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),
- &tmp, sizeof(tmp)) != sizeof(tmp))
- return 0;
- min_index = l2_cache_new_entry(bs);
- l2_table = s->l2_cache + (min_index << s->l2_bits);
+ /* seek if the table for the given offset is in the cache */
- if (old_l2_offset == 0) {
- memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
- } else {
- if (bdrv_pread(s->hd, old_l2_offset,
- l2_table, s->l2_size * sizeof(uint64_t)) !=
- s->l2_size * sizeof(uint64_t))
- return 0;
- }
- if (bdrv_pwrite(s->hd, l2_offset,
- l2_table, s->l2_size * sizeof(uint64_t)) !=
- s->l2_size * sizeof(uint64_t))
- return 0;
+ l2_table = seek_l2_table(s, l2_offset);
+ if (l2_table != NULL)
+ return l2_table;
+
+ /* not found: load a new entry in the least used one */
+
+ min_index = l2_cache_new_entry(bs);
+ l2_table = s->l2_cache + (min_index << s->l2_bits);
+ if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
+ s->l2_size * sizeof(uint64_t))
+ return NULL;
+ s->l2_cache_offsets[min_index] = l2_offset;
+ s->l2_cache_counts[min_index] = 1;
+
+ return l2_table;
+}
+
+/*
+ * l2_allocate
+ *
+ * Allocate a new l2 entry in the file. If l1_index points to an already
+ * used entry in the L2 table (i.e. we are doing a copy on write for the L2
+ * table) copy the contents of the old L2 table into the newly allocated one.
+ * Otherwise the new table is initialized with zeros.
+ *
+ */
+
+static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index)
+{
+ BDRVQcowState *s = bs->opaque;
+ int min_index;
+ uint64_t old_l2_offset, tmp;
+ uint64_t *l2_table, l2_offset;
+
+ old_l2_offset = s->l1_table[l1_index];
+
+ /* allocate a new l2 entry */
+
+ l2_offset = alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
+
+ /* update the L1 entry */
+
+ s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
+
+ tmp = cpu_to_be64(l2_offset | QCOW_OFLAG_COPIED);
+ if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),
+ &tmp, sizeof(tmp)) != sizeof(tmp))
+ return NULL;
+
+ /* allocate a new entry in the l2 cache */
+
+ min_index = l2_cache_new_entry(bs);
+ l2_table = s->l2_cache + (min_index << s->l2_bits);
+
+ if (old_l2_offset == 0) {
+ /* if there was no old l2 table, clear the new table */
+ memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
} else {
- if (!(l2_offset & QCOW_OFLAG_COPIED)) {
- if (allocate) {
- free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
- goto l2_allocate;
- }
- } else {
- l2_offset &= ~QCOW_OFLAG_COPIED;
- }
- for(i = 0; i < L2_CACHE_SIZE; i++) {
- if (l2_offset == s->l2_cache_offsets[i]) {
- /* increment the hit count */
- if (++s->l2_cache_counts[i] == 0xffffffff) {
- for(j = 0; j < L2_CACHE_SIZE; j++) {
- s->l2_cache_counts[j] >>= 1;
- }
- }
- l2_table = s->l2_cache + (i << s->l2_bits);
- goto found;
- }
- }
- /* not found: load a new entry in the least used one */
- min_index = l2_cache_new_entry(bs);
- l2_table = s->l2_cache + (min_index << s->l2_bits);
- if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
+ /* if there was an old l2 table, read it from the disk */
+ if (bdrv_pread(s->hd, old_l2_offset,
+ l2_table, s->l2_size * sizeof(uint64_t)) !=
s->l2_size * sizeof(uint64_t))
- return 0;
+ return NULL;
}
+ /* write the l2 table to the file */
+ if (bdrv_pwrite(s->hd, l2_offset,
+ l2_table, s->l2_size * sizeof(uint64_t)) !=
+ s->l2_size * sizeof(uint64_t))
+ return NULL;
+
+ /* update the l2 cache entry */
+
s->l2_cache_offsets[min_index] = l2_offset;
s->l2_cache_counts[min_index] = 1;
- found:
+
+ return l2_table;
+}
+
+static int size_to_clusters(BDRVQcowState *s, int64_t size)
+{
+ return (size + (s->cluster_size - 1)) >> s->cluster_bits;
+}
+
+static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size,
+ uint64_t *l2_table, uint64_t start, uint64_t mask)
+{
+ int i;
+ uint64_t offset = be64_to_cpu(l2_table[0]) & ~mask;
+
+ if (!offset)
+ return 0;
+
+ for (i = start; i < start + nb_clusters; i++)
+ if (offset + i * cluster_size != (be64_to_cpu(l2_table[i]) & ~mask))
+ break;
+
+ return (i - start);
+}
+
+static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table)
+{
+ int i = 0;
+
+ while(nb_clusters-- && l2_table[i] == 0)
+ i++;
+
+ return i;
+}
+
+/*
+ * get_cluster_offset
+ *
+ * For a given offset of the disk image, return cluster offset in
+ * qcow2 file.
+ *
+ * on entry, *num is the number of contiguous clusters we'd like to
+ * access following offset.
+ *
+ * on exit, *num is the number of contiguous clusters we can read.
+ *
+ * Return 1, if the offset is found
+ * Return 0, otherwise.
+ *
+ */
+
+static uint64_t get_cluster_offset(BlockDriverState *bs,
+ uint64_t offset, int *num)
+{
+ BDRVQcowState *s = bs->opaque;
+ int l1_index, l2_index;
+ uint64_t l2_offset, *l2_table, cluster_offset;
+ int l1_bits, c;
+ int index_in_cluster, nb_available, nb_needed, nb_clusters;
+
+ index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1);
+ nb_needed = *num + index_in_cluster;
+
+ l1_bits = s->l2_bits + s->cluster_bits;
+
+ /* compute how many bytes there are between the offset and
+ * the end of the l1 entry
+ */
+
+ nb_available = (1 << l1_bits) - (offset & ((1 << l1_bits) - 1));
+
+ /* compute the number of available sectors */
+
+ nb_available = (nb_available >> 9) + index_in_cluster;
+
+ if (nb_needed > nb_available) {
+ nb_needed = nb_available;
+ }
+
+ cluster_offset = 0;
+
+ /* seek the the l2 offset in the l1 table */
+
+ l1_index = offset >> l1_bits;
+ if (l1_index >= s->l1_size)
+ goto out;
+
+ l2_offset = s->l1_table[l1_index];
+
+ /* seek the l2 table of the given l2 offset */
+
+ if (!l2_offset)
+ goto out;
+
+ /* load the l2 table in memory */
+
+ l2_offset &= ~QCOW_OFLAG_COPIED;
+ l2_table = l2_load(bs, l2_offset);
+ if (l2_table == NULL)
+ return 0;
+
+ /* find the cluster offset for the given disk offset */
+
l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
cluster_offset = be64_to_cpu(l2_table[l2_index]);
+ nb_clusters = size_to_clusters(s, nb_needed << 9);
+
if (!cluster_offset) {
- if (!allocate)
- return cluster_offset;
- } else if (!(cluster_offset & QCOW_OFLAG_COPIED)) {
- if (!allocate)
- return cluster_offset;
- /* free the cluster */
- if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
- 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);
- } else {
- free_clusters(bs, cluster_offset, s->cluster_size);
- }
+ /* how many empty clusters ? */
+ c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]);
} else {
- cluster_offset &= ~QCOW_OFLAG_COPIED;
- return cluster_offset;
+ /* how many allocated clusters ? */
+ c = count_contiguous_clusters(nb_clusters, s->cluster_size,
+ &l2_table[l2_index], 0, QCOW_OFLAG_COPIED);
}
- if (allocate == 1) {
- /* allocate a new cluster */
- cluster_offset = alloc_clusters(bs, s->cluster_size);
- /* we must initialize the cluster content which won't be
- written */
- if ((n_end - n_start) < s->cluster_sectors) {
- uint64_t start_sect;
+ nb_available = (c * s->cluster_sectors);
+out:
+ if (nb_available > nb_needed)
+ nb_available = nb_needed;
- start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
- ret = copy_sectors(bs, start_sect,
- cluster_offset, 0, n_start);
- if (ret < 0)
- return 0;
- ret = copy_sectors(bs, start_sect,
- cluster_offset, n_end, s->cluster_sectors);
- if (ret < 0)
- return 0;
- }
- tmp = cpu_to_be64(cluster_offset | QCOW_OFLAG_COPIED);
- } else {
+ *num = nb_available - index_in_cluster;
+
+ return cluster_offset & ~QCOW_OFLAG_COPIED;
+}
+
+/*
+ * free_any_clusters
+ *
+ * free clusters according to its type: compressed or not
+ *
+ */
+
+static void free_any_clusters(BlockDriverState *bs,
+ uint64_t cluster_offset, int nb_clusters)
+{
+ BDRVQcowState *s = bs->opaque;
+
+ /* free the cluster */
+
+ if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
int nb_csectors;
- cluster_offset = alloc_bytes(bs, compressed_size);
- nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
- (cluster_offset >> 9);
- cluster_offset |= QCOW_OFLAG_COMPRESSED |
- ((uint64_t)nb_csectors << s->csize_shift);
- /* compressed clusters never have the copied flag */
- tmp = cpu_to_be64(cluster_offset);
+ nb_csectors = ((cluster_offset >> s->csize_shift) &
+ s->csize_mask) + 1;
+ free_clusters(bs, (cluster_offset & s->cluster_offset_mask) & ~511,
+ nb_csectors * 512);
+ return;
}
+
+ free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits);
+
+ return;
+}
+
+/*
+ * get_cluster_table
+ *
+ * for a given disk offset, load (and allocate if needed)
+ * the l2 table.
+ *
+ * the l2 table offset in the qcow2 file and the cluster index
+ * in the l2 table are given to the caller.
+ *
+ */
+
+static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
+ uint64_t **new_l2_table,
+ uint64_t *new_l2_offset,
+ int *new_l2_index)
+{
+ BDRVQcowState *s = bs->opaque;
+ int l1_index, l2_index, ret;
+ uint64_t l2_offset, *l2_table;
+
+ /* seek the the l2 offset in the l1 table */
+
+ l1_index = offset >> (s->l2_bits + s->cluster_bits);
+ if (l1_index >= s->l1_size) {
+ ret = grow_l1_table(bs, l1_index + 1);
+ if (ret < 0)
+ return 0;
+ }
+ l2_offset = s->l1_table[l1_index];
+
+ /* seek the l2 table of the given l2 offset */
+
+ if (l2_offset & QCOW_OFLAG_COPIED) {
+ /* load the l2 table in memory */
+ l2_offset &= ~QCOW_OFLAG_COPIED;
+ l2_table = l2_load(bs, l2_offset);
+ if (l2_table == NULL)
+ return 0;
+ } else {
+ if (l2_offset)
+ free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
+ l2_table = l2_allocate(bs, l1_index);
+ if (l2_table == NULL)
+ return 0;
+ l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED;
+ }
+
+ /* find the cluster offset for the given disk offset */
+
+ l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
+
+ *new_l2_table = l2_table;
+ *new_l2_offset = l2_offset;
+ *new_l2_index = l2_index;
+
+ return 1;
+}
+
+/*
+ * alloc_compressed_cluster_offset
+ *
+ * For a given offset of the disk image, return cluster offset in
+ * qcow2 file.
+ *
+ * If the offset is not found, allocate a new compressed cluster.
+ *
+ * Return the cluster offset if successful,
+ * Return 0, otherwise.
+ *
+ */
+
+static uint64_t alloc_compressed_cluster_offset(BlockDriverState *bs,
+ uint64_t offset,
+ int compressed_size)
+{
+ BDRVQcowState *s = bs->opaque;
+ int l2_index, ret;
+ uint64_t l2_offset, *l2_table, cluster_offset;
+ int nb_csectors;
+
+ ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
+ if (ret == 0)
+ return 0;
+
+ cluster_offset = be64_to_cpu(l2_table[l2_index]);
+ if (cluster_offset & QCOW_OFLAG_COPIED)
+ return cluster_offset & ~QCOW_OFLAG_COPIED;
+
+ if (cluster_offset)
+ free_any_clusters(bs, cluster_offset, 1);
+
+ cluster_offset = alloc_bytes(bs, compressed_size);
+ nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
+ (cluster_offset >> 9);
+
+ cluster_offset |= QCOW_OFLAG_COMPRESSED |
+ ((uint64_t)nb_csectors << s->csize_shift);
+
/* update L2 table */
- l2_table[l2_index] = tmp;
+
+ /* compressed clusters never have the copied flag */
+
+ l2_table[l2_index] = cpu_to_be64(cluster_offset);
if (bdrv_pwrite(s->hd,
- l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp))
+ l2_offset + l2_index * sizeof(uint64_t),
+ l2_table + l2_index,
+ sizeof(uint64_t)) != sizeof(uint64_t))
return 0;
+
+ return cluster_offset;
+}
+
+typedef struct QCowL2Meta
+{
+ uint64_t offset;
+ int n_start;
+ int nb_available;
+ int nb_clusters;
+} QCowL2Meta;
+
+static int alloc_cluster_link_l2(BlockDriverState *bs, uint64_t cluster_offset,
+ QCowL2Meta *m)
+{
+ BDRVQcowState *s = bs->opaque;
+ int i, j = 0, l2_index, ret;
+ uint64_t *old_cluster, start_sect, l2_offset, *l2_table;
+
+ if (m->nb_clusters == 0)
+ return 0;
+
+ old_cluster = qemu_malloc(m->nb_clusters * sizeof(uint64_t));
+
+ /* copy content of unmodified sectors */
+ start_sect = (m->offset & ~(s->cluster_size - 1)) >> 9;
+ if (m->n_start) {
+ ret = copy_sectors(bs, start_sect, cluster_offset, 0, m->n_start);
+ if (ret < 0)
+ goto err;
+ }
+
+ if (m->nb_available & (s->cluster_sectors - 1)) {
+ uint64_t end = m->nb_available & ~(uint64_t)(s->cluster_sectors - 1);
+ ret = copy_sectors(bs, start_sect + end, cluster_offset + (end << 9),
+ m->nb_available - end, s->cluster_sectors);
+ if (ret < 0)
+ goto err;
+ }
+
+ ret = -EIO;
+ /* update L2 table */
+ if (!get_cluster_table(bs, m->offset, &l2_table, &l2_offset, &l2_index))
+ goto err;
+
+ for (i = 0; i < m->nb_clusters; i++) {
+ if(l2_table[l2_index + i] != 0)
+ old_cluster[j++] = l2_table[l2_index + i];
+
+ l2_table[l2_index + i] = cpu_to_be64((cluster_offset +
+ (i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
+ }
+
+ if (bdrv_pwrite(s->hd, l2_offset + l2_index * sizeof(uint64_t),
+ l2_table + l2_index, m->nb_clusters * sizeof(uint64_t)) !=
+ m->nb_clusters * sizeof(uint64_t))
+ goto err;
+
+ for (i = 0; i < j; i++)
+ free_any_clusters(bs, be64_to_cpu(old_cluster[i]), 1);
+
+ ret = 0;
+err:
+ qemu_free(old_cluster);
+ return ret;
+ }
+
+/*
+ * alloc_cluster_offset
+ *
+ * For a given offset of the disk image, return cluster offset in
+ * qcow2 file.
+ *
+ * If the offset is not found, allocate a new cluster.
+ *
+ * Return the cluster offset if successful,
+ * Return 0, otherwise.
+ *
+ */
+
+static uint64_t alloc_cluster_offset(BlockDriverState *bs,
+ uint64_t offset,
+ int n_start, int n_end,
+ int *num, QCowL2Meta *m)
+{
+ BDRVQcowState *s = bs->opaque;
+ int l2_index, ret;
+ uint64_t l2_offset, *l2_table, cluster_offset;
+ int nb_clusters, i = 0;
+
+ ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
+ if (ret == 0)
+ return 0;
+
+ nb_clusters = size_to_clusters(s, n_end << 9);
+
+ nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
+
+ cluster_offset = be64_to_cpu(l2_table[l2_index]);
+
+ /* We keep all QCOW_OFLAG_COPIED clusters */
+
+ if (cluster_offset & QCOW_OFLAG_COPIED) {
+ nb_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size,
+ &l2_table[l2_index], 0, 0);
+
+ cluster_offset &= ~QCOW_OFLAG_COPIED;
+ m->nb_clusters = 0;
+
+ goto out;
+ }
+
+ /* for the moment, multiple compressed clusters are not managed */
+
+ if (cluster_offset & QCOW_OFLAG_COMPRESSED)
+ nb_clusters = 1;
+
+ /* how many available clusters ? */
+
+ while (i < nb_clusters) {
+ i += count_contiguous_clusters(nb_clusters - i, s->cluster_size,
+ &l2_table[l2_index], i, 0);
+
+ if(be64_to_cpu(l2_table[l2_index + i]))
+ break;
+
+ i += count_contiguous_free_clusters(nb_clusters - i,
+ &l2_table[l2_index + i]);
+
+ cluster_offset = be64_to_cpu(l2_table[l2_index + i]);
+
+ if ((cluster_offset & QCOW_OFLAG_COPIED) ||
+ (cluster_offset & QCOW_OFLAG_COMPRESSED))
+ break;
+ }
+ nb_clusters = i;
+
+ /* allocate a new cluster */
+
+ cluster_offset = alloc_clusters(bs, nb_clusters * s->cluster_size);
+
+ /* save info needed for meta data update */
+ m->offset = offset;
+ m->n_start = n_start;
+ m->nb_clusters = nb_clusters;
+
+out:
+ m->nb_available = MIN(nb_clusters << (s->cluster_bits - 9), n_end);
+
+ *num = m->nb_available - n_start;
+
return cluster_offset;
}
static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int *pnum)
{
- BDRVQcowState *s = bs->opaque;
- int index_in_cluster, n;
uint64_t cluster_offset;
- cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
- index_in_cluster = sector_num & (s->cluster_sectors - 1);
- n = s->cluster_sectors - index_in_cluster;
- if (n > nb_sectors)
- n = nb_sectors;
- *pnum = n;
+ *pnum = nb_sectors;
+ cluster_offset = get_cluster_offset(bs, sector_num << 9, pnum);
+
return (cluster_offset != 0);
}
uint64_t cluster_offset;
while (nb_sectors > 0) {
- cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
+ n = nb_sectors;
+ cluster_offset = get_cluster_offset(bs, sector_num << 9, &n);
index_in_cluster = sector_num & (s->cluster_sectors - 1);
- n = s->cluster_sectors - index_in_cluster;
- if (n > nb_sectors)
- n = nb_sectors;
if (!cluster_offset) {
if (bs->backing_hd) {
/* read from the base image */
BDRVQcowState *s = bs->opaque;
int ret, index_in_cluster, n;
uint64_t cluster_offset;
+ int n_end;
+ QCowL2Meta l2meta;
while (nb_sectors > 0) {
index_in_cluster = sector_num & (s->cluster_sectors - 1);
- n = s->cluster_sectors - index_in_cluster;
- if (n > nb_sectors)
- n = nb_sectors;
- cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0,
- index_in_cluster,
- index_in_cluster + n);
+ n_end = index_in_cluster + nb_sectors;
+ if (s->crypt_method &&
+ n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors)
+ n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors;
+ cluster_offset = alloc_cluster_offset(bs, sector_num << 9,
+ index_in_cluster,
+ n_end, &n, &l2meta);
if (!cluster_offset)
return -1;
if (s->crypt_method) {
} else {
ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
}
- if (ret != n * 512)
+ if (ret != n * 512 || alloc_cluster_link_l2(bs, cluster_offset, &l2meta) < 0) {
+ free_any_clusters(bs, cluster_offset, l2meta.nb_clusters);
return -1;
+ }
nb_sectors -= n;
sector_num += n;
buf += n * 512;
typedef struct QCowAIOCB {
BlockDriverAIOCB common;
int64_t sector_num;
+ QEMUIOVector *qiov;
uint8_t *buf;
+ void *orig_buf;
int nb_sectors;
int n;
uint64_t cluster_offset;
uint8_t *cluster_data;
BlockDriverAIOCB *hd_aiocb;
+ struct iovec hd_iov;
+ QEMUIOVector hd_qiov;
+ QEMUBH *bh;
+ QCowL2Meta l2meta;
} QCowAIOCB;
+static void qcow_aio_read_cb(void *opaque, int ret);
+static void qcow_aio_read_bh(void *opaque)
+{
+ QCowAIOCB *acb = opaque;
+ qemu_bh_delete(acb->bh);
+ acb->bh = NULL;
+ qcow_aio_read_cb(opaque, 0);
+}
+
+static int qcow_schedule_bh(QEMUBHFunc *cb, QCowAIOCB *acb)
+{
+ if (acb->bh)
+ return -EIO;
+
+ acb->bh = qemu_bh_new(cb, acb);
+ if (!acb->bh)
+ return -EIO;
+
+ qemu_bh_schedule(acb->bh);
+
+ return 0;
+}
+
static void qcow_aio_read_cb(void *opaque, int ret)
{
QCowAIOCB *acb = opaque;
int index_in_cluster, n1;
acb->hd_aiocb = NULL;
- if (ret < 0) {
- fail:
- acb->common.cb(acb->common.opaque, ret);
- qemu_aio_release(acb);
- return;
- }
+ if (ret < 0)
+ goto done;
- redo:
/* post process the read buffer */
if (!acb->cluster_offset) {
/* nothing to do */
if (acb->nb_sectors == 0) {
/* request completed */
- acb->common.cb(acb->common.opaque, 0);
- qemu_aio_release(acb);
- return;
+ ret = 0;
+ goto done;
}
/* prepare next AIO request */
- acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9,
- 0, 0, 0, 0);
+ acb->n = acb->nb_sectors;
+ acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, &acb->n);
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
- acb->n = s->cluster_sectors - index_in_cluster;
- if (acb->n > acb->nb_sectors)
- acb->n = acb->nb_sectors;
if (!acb->cluster_offset) {
if (bs->backing_hd) {
n1 = backing_read1(bs->backing_hd, acb->sector_num,
acb->buf, acb->n);
if (n1 > 0) {
- acb->hd_aiocb = bdrv_aio_read(bs->backing_hd, acb->sector_num,
- acb->buf, acb->n, qcow_aio_read_cb, acb);
+ acb->hd_iov.iov_base = (void *)acb->buf;
+ acb->hd_iov.iov_len = acb->n * 512;
+ qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
+ acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
+ &acb->hd_qiov, acb->n,
+ qcow_aio_read_cb, acb);
if (acb->hd_aiocb == NULL)
- goto fail;
+ goto done;
} else {
- goto redo;
+ ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
+ if (ret < 0)
+ goto done;
}
} else {
/* Note: in this case, no need to wait */
memset(acb->buf, 0, 512 * acb->n);
- goto redo;
+ ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
+ if (ret < 0)
+ goto done;
}
} else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
/* add AIO support for compressed blocks ? */
if (decompress_cluster(s, acb->cluster_offset) < 0)
- goto fail;
+ goto done;
memcpy(acb->buf,
s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
- goto redo;
+ ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
+ if (ret < 0)
+ goto done;
} else {
if ((acb->cluster_offset & 511) != 0) {
ret = -EIO;
- goto fail;
+ goto done;
}
- acb->hd_aiocb = bdrv_aio_read(s->hd,
+
+ acb->hd_iov.iov_base = (void *)acb->buf;
+ acb->hd_iov.iov_len = acb->n * 512;
+ qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
+ acb->hd_aiocb = bdrv_aio_readv(s->hd,
(acb->cluster_offset >> 9) + index_in_cluster,
- acb->buf, acb->n, qcow_aio_read_cb, acb);
+ &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
if (acb->hd_aiocb == NULL)
- goto fail;
+ goto done;
+ }
+
+ return;
+done:
+ if (acb->qiov->niov > 1) {
+ qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size);
+ qemu_vfree(acb->orig_buf);
}
+ acb->common.cb(acb->common.opaque, ret);
+ qemu_aio_release(acb);
}
static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
- int64_t sector_num, uint8_t *buf, int nb_sectors,
- BlockDriverCompletionFunc *cb, void *opaque)
+ int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
+ BlockDriverCompletionFunc *cb, void *opaque, int is_write)
{
QCowAIOCB *acb;
return NULL;
acb->hd_aiocb = NULL;
acb->sector_num = sector_num;
- acb->buf = buf;
+ acb->qiov = qiov;
+ if (qiov->niov > 1) {
+ acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size);
+ if (is_write)
+ qemu_iovec_to_buffer(qiov, acb->buf);
+ } else {
+ acb->buf = (uint8_t *)qiov->iov->iov_base;
+ }
acb->nb_sectors = nb_sectors;
acb->n = 0;
acb->cluster_offset = 0;
+ acb->l2meta.nb_clusters = 0;
return acb;
}
-static BlockDriverAIOCB *qcow_aio_read(BlockDriverState *bs,
- int64_t sector_num, uint8_t *buf, int nb_sectors,
+static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
+ int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque)
{
QCowAIOCB *acb;
- acb = qcow_aio_setup(bs, sector_num, buf, nb_sectors, cb, opaque);
+ acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
if (!acb)
return NULL;
BlockDriverState *bs = acb->common.bs;
BDRVQcowState *s = bs->opaque;
int index_in_cluster;
- uint64_t cluster_offset;
const uint8_t *src_buf;
+ int n_end;
acb->hd_aiocb = NULL;
- if (ret < 0) {
- fail:
- acb->common.cb(acb->common.opaque, ret);
- qemu_aio_release(acb);
- return;
+ if (ret < 0)
+ goto done;
+
+ if (alloc_cluster_link_l2(bs, acb->cluster_offset, &acb->l2meta) < 0) {
+ free_any_clusters(bs, acb->cluster_offset, acb->l2meta.nb_clusters);
+ goto done;
}
acb->nb_sectors -= acb->n;
if (acb->nb_sectors == 0) {
/* request completed */
- acb->common.cb(acb->common.opaque, 0);
- qemu_aio_release(acb);
- return;
+ ret = 0;
+ goto done;
}
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
- acb->n = s->cluster_sectors - index_in_cluster;
- if (acb->n > acb->nb_sectors)
- acb->n = acb->nb_sectors;
- cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 1, 0,
- index_in_cluster,
- index_in_cluster + acb->n);
- if (!cluster_offset || (cluster_offset & 511) != 0) {
+ n_end = index_in_cluster + acb->nb_sectors;
+ if (s->crypt_method &&
+ n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors)
+ n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors;
+
+ acb->cluster_offset = alloc_cluster_offset(bs, acb->sector_num << 9,
+ index_in_cluster,
+ n_end, &acb->n, &acb->l2meta);
+ if (!acb->cluster_offset || (acb->cluster_offset & 511) != 0) {
ret = -EIO;
- goto fail;
+ goto done;
}
if (s->crypt_method) {
if (!acb->cluster_data) {
- acb->cluster_data = qemu_mallocz(s->cluster_size);
- if (!acb->cluster_data) {
- ret = -ENOMEM;
- goto fail;
- }
+ acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS *
+ s->cluster_size);
}
encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
acb->n, 1, &s->aes_encrypt_key);
} else {
src_buf = acb->buf;
}
- acb->hd_aiocb = bdrv_aio_write(s->hd,
- (cluster_offset >> 9) + index_in_cluster,
- src_buf, acb->n,
- qcow_aio_write_cb, acb);
+ acb->hd_iov.iov_base = (void *)src_buf;
+ acb->hd_iov.iov_len = acb->n * 512;
+ qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
+ acb->hd_aiocb = bdrv_aio_writev(s->hd,
+ (acb->cluster_offset >> 9) + index_in_cluster,
+ &acb->hd_qiov, acb->n,
+ qcow_aio_write_cb, acb);
if (acb->hd_aiocb == NULL)
- goto fail;
+ goto done;
+
+ return;
+
+done:
+ if (acb->qiov->niov > 1)
+ qemu_vfree(acb->orig_buf);
+ acb->common.cb(acb->common.opaque, ret);
+ qemu_aio_release(acb);
}
-static BlockDriverAIOCB *qcow_aio_write(BlockDriverState *bs,
- int64_t sector_num, const uint8_t *buf, int nb_sectors,
+static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
+ int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque)
{
BDRVQcowState *s = bs->opaque;
s->cluster_cache_offset = -1; /* disable compressed cache */
- acb = qcow_aio_setup(bs, sector_num, (uint8_t*)buf, nb_sectors, cb, opaque);
+ acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
if (!acb)
return NULL;
}
}
-static int qcow_create(const char *filename, int64_t total_size,
- const char *backing_file, int flags)
+static int qcow_create2(const char *filename, int64_t total_size,
+ const char *backing_file, const char *backing_format,
+ int flags)
{
+
int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
+ int ref_clusters, backing_format_len = 0;
QCowHeader header;
uint64_t tmp, offset;
QCowCreateState s1, *s = &s1;
+ QCowExtension ext_bf = {0, 0};
+
memset(s, 0, sizeof(*s));
header_size = sizeof(header);
backing_filename_len = 0;
if (backing_file) {
+ if (backing_format) {
+ ext_bf.magic = QCOW_EXT_MAGIC_BACKING_FORMAT;
+ backing_format_len = strlen(backing_format);
+ ext_bf.len = (backing_format_len + 7) & ~7;
+ header_size += ((sizeof(ext_bf) + ext_bf.len + 7) & ~7);
+ }
header.backing_file_offset = cpu_to_be64(header_size);
backing_filename_len = strlen(backing_file);
header.backing_file_size = cpu_to_be32(backing_filename_len);
offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size);
s->refcount_table = qemu_mallocz(s->cluster_size);
- if (!s->refcount_table)
- goto fail;
- s->refcount_block = qemu_mallocz(s->cluster_size);
- if (!s->refcount_block)
- goto fail;
s->refcount_table_offset = offset;
header.refcount_table_offset = cpu_to_be64(offset);
header.refcount_table_clusters = cpu_to_be32(1);
offset += s->cluster_size;
-
- s->refcount_table[0] = cpu_to_be64(offset);
s->refcount_block_offset = offset;
- offset += s->cluster_size;
+
+ /* count how many refcount blocks needed */
+ tmp = offset >> s->cluster_bits;
+ ref_clusters = (tmp >> (s->cluster_bits - REFCOUNT_SHIFT)) + 1;
+ for (i=0; i < ref_clusters; i++) {
+ s->refcount_table[i] = cpu_to_be64(offset);
+ offset += s->cluster_size;
+ }
+
+ s->refcount_block = qemu_mallocz(ref_clusters * s->cluster_size);
/* update refcounts */
create_refcount_update(s, 0, header_size);
create_refcount_update(s, s->l1_table_offset, l1_size * sizeof(uint64_t));
create_refcount_update(s, s->refcount_table_offset, s->cluster_size);
- create_refcount_update(s, s->refcount_block_offset, s->cluster_size);
+ create_refcount_update(s, s->refcount_block_offset, ref_clusters * s->cluster_size);
/* write all the data */
write(fd, &header, sizeof(header));
if (backing_file) {
+ if (backing_format_len) {
+ char zero[16];
+ int d = ext_bf.len - backing_format_len;
+
+ memset(zero, 0, sizeof(zero));
+ cpu_to_be32s(&ext_bf.magic);
+ cpu_to_be32s(&ext_bf.len);
+ write(fd, &ext_bf, sizeof(ext_bf));
+ write(fd, backing_format, backing_format_len);
+ if (d>0) {
+ write(fd, zero, d);
+ }
+ }
write(fd, backing_file, backing_filename_len);
}
lseek(fd, s->l1_table_offset, SEEK_SET);
write(fd, s->refcount_table, s->cluster_size);
lseek(fd, s->refcount_block_offset, SEEK_SET);
- write(fd, s->refcount_block, s->cluster_size);
+ write(fd, s->refcount_block, ref_clusters * s->cluster_size);
qemu_free(s->refcount_table);
qemu_free(s->refcount_block);
close(fd);
return 0;
- fail:
- qemu_free(s->refcount_table);
- qemu_free(s->refcount_block);
- close(fd);
- return -ENOMEM;
+}
+
+static int qcow_create(const char *filename, int64_t total_size,
+ const char *backing_file, int flags)
+{
+ return qcow_create2(filename, total_size, backing_file, NULL, flags);
}
static int qcow_make_empty(BlockDriverState *bs)
memset(s->l1_table, 0, l1_length);
if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
- return -1;
+ return -1;
ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
if (ret < 0)
return ret;
return -EINVAL;
out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
- if (!out_buf)
- return -ENOMEM;
/* best compression, small window, no zlib header */
memset(&strm, 0, sizeof(strm));
/* could not compress: write normal cluster */
qcow_write(bs, sector_num, buf, s->cluster_sectors);
} else {
- cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
- out_len, 0, 0);
+ cluster_offset = alloc_compressed_cluster_offset(bs, sector_num << 9,
+ out_len);
+ if (!cluster_offset)
+ return -1;
cluster_offset &= s->cluster_offset_mask;
if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
qemu_free(out_buf);
l1_allocated = 0;
if (l1_table_offset != s->l1_table_offset) {
l1_table = qemu_malloc(l1_size2);
- if (!l1_table)
- goto fail;
l1_allocated = 1;
if (bdrv_pread(s->hd, l1_table_offset,
l1_table, l1_size2) != l1_size2)
l2_size = s->l2_size * sizeof(uint64_t);
l2_table = qemu_malloc(l2_size);
- if (!l2_table)
- goto fail;
l1_modified = 0;
for(i = 0; i < l1_size; i++) {
l2_offset = l1_table[i];
int64_t offset;
uint32_t extra_data_size;
+ if (!s->nb_snapshots) {
+ s->snapshots = NULL;
+ s->snapshots_size = 0;
+ return 0;
+ }
+
offset = s->snapshots_offset;
s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot));
- if (!s->snapshots)
- goto fail;
for(i = 0; i < s->nb_snapshots; i++) {
offset = align_offset(offset, 8);
if (bdrv_pread(s->hd, offset, &h, sizeof(h)) != sizeof(h))
offset += extra_data_size;
sn->id_str = qemu_malloc(id_str_size + 1);
- if (!sn->id_str)
- goto fail;
if (bdrv_pread(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
goto fail;
offset += id_str_size;
sn->id_str[id_str_size] = '\0';
sn->name = qemu_malloc(name_size + 1);
- if (!sn->name)
- goto fail;
if (bdrv_pread(s->hd, offset, sn->name, name_size) != name_size)
goto fail;
offset += name_size;
sn->l1_size = s->l1_size;
l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
- if (!l1_table)
- goto fail;
for(i = 0; i < s->l1_size; i++) {
l1_table[i] = cpu_to_be64(s->l1_table[i]);
}
l1_table = NULL;
snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot));
- if (!snapshots1)
- goto fail;
- memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));
+ if (s->snapshots) {
+ memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));
+ qemu_free(s->snapshots);
+ }
s->snapshots = snapshots1;
s->snapshots[s->nb_snapshots++] = *sn;
int i;
sn_tab = qemu_mallocz(s->nb_snapshots * sizeof(QEMUSnapshotInfo));
- if (!sn_tab)
- goto fail;
for(i = 0; i < s->nb_snapshots; i++) {
sn_info = sn_tab + i;
sn = s->snapshots + i;
}
*psn_tab = sn_tab;
return s->nb_snapshots;
- fail:
- qemu_free(sn_tab);
- *psn_tab = NULL;
- return -ENOMEM;
}
/*********************************************************/
int ret, refcount_table_size2, i;
s->refcount_block_cache = qemu_malloc(s->cluster_size);
- if (!s->refcount_block_cache)
- goto fail;
refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t);
s->refcount_table = qemu_malloc(refcount_table_size2);
- if (!s->refcount_table)
- goto fail;
if (s->refcount_table_size > 0) {
ret = bdrv_pread(s->hd, s->refcount_table_offset,
s->refcount_table, refcount_table_size2);
BDRVQcowState *s = bs->opaque;
int i, nb_clusters;
- nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
- for(;;) {
- if (get_refcount(bs, s->free_cluster_index) == 0) {
- s->free_cluster_index++;
- for(i = 1; i < nb_clusters; i++) {
- if (get_refcount(bs, s->free_cluster_index) != 0)
- goto not_found;
- s->free_cluster_index++;
- }
+ 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)
+ goto retry;
+ }
#ifdef DEBUG_ALLOC2
- printf("alloc_clusters: size=%lld -> %lld\n",
- size,
- (s->free_cluster_index - nb_clusters) << s->cluster_bits);
+ printf("alloc_clusters: size=%lld -> %lld\n",
+ size,
+ (s->free_cluster_index - nb_clusters) << s->cluster_bits);
#endif
- return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
- } else {
- not_found:
- s->free_cluster_index++;
- }
- }
+ return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
}
static int64_t alloc_clusters(BlockDriverState *bs, int64_t size)
int new_table_size, new_table_size2, refcount_table_clusters, i, ret;
uint64_t *new_table;
int64_t table_offset;
- uint64_t data64;
- uint32_t data32;
+ uint8_t data[12];
int old_table_size;
int64_t old_table_offset;
#endif
new_table_size2 = new_table_size * sizeof(uint64_t);
new_table = qemu_mallocz(new_table_size2);
- if (!new_table)
- return -ENOMEM;
memcpy(new_table, s->refcount_table,
s->refcount_table_size * sizeof(uint64_t));
for(i = 0; i < s->refcount_table_size; i++)
for(i = 0; i < s->refcount_table_size; i++)
be64_to_cpus(&new_table[i]);
- data64 = cpu_to_be64(table_offset);
+ 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),
- &data64, sizeof(data64)) != sizeof(data64))
- goto fail;
- data32 = cpu_to_be32(refcount_table_clusters);
- if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_clusters),
- &data32, sizeof(data32)) != sizeof(data32))
+ data, sizeof(data)) != sizeof(data))
goto fail;
qemu_free(s->refcount_table);
old_table_offset = s->refcount_table_offset;
}
}
-#ifdef DEBUG_ALLOC
-static void inc_refcounts(BlockDriverState *bs,
+/*
+ * 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 the the refcount table saved in the image.
+ *
+ * Returns the number of errors in the image that were found
+ */
+static int inc_refcounts(BlockDriverState *bs,
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;
+ return 0;
start = offset & ~(s->cluster_size - 1);
last = (offset + size - 1) & ~(s->cluster_size - 1);
cluster_offset += s->cluster_size) {
k = cluster_offset >> s->cluster_bits;
if (k < 0 || k >= refcount_table_size) {
- printf("ERROR: invalid cluster offset=0x%llx\n", cluster_offset);
+ fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n",
+ cluster_offset);
+ errors++;
} else {
if (++refcount_table[k] == 0) {
- printf("ERROR: overflow cluster offset=0x%llx\n", cluster_offset);
+ fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64
+ "\n", cluster_offset);
+ errors++;
}
}
}
+
+ return errors;
+}
+
+/*
+ * 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,
+ 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)
+ goto fail;
+
+ /* 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;
+ errors++;
+ }
+
+ /* 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);
+ } 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 == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) {
+ fprintf(stderr, "ERROR OFLAG_COPIED: offset=%"
+ PRIx64 " refcount=%d\n", entry, refcount);
+ errors++;
+ }
+ }
+
+ /* Mark cluster as used */
+ offset &= ~QCOW_OFLAG_COPIED;
+ errors += inc_refcounts(bs, 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++;
+ }
+ }
+ }
+ }
+
+ qemu_free(l2_table);
+ return errors;
+
+fail:
+ fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
+ qemu_free(l2_table);
+ return -EIO;
}
+/*
+ * 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,
uint16_t *refcount_table,
int refcount_table_size,
int check_copied)
{
BDRVQcowState *s = bs->opaque;
- uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2;
- int l2_size, i, j, nb_csectors, refcount;
+ uint64_t *l1_table, l2_offset, l1_size2;
+ int i, refcount, ret;
+ int errors = 0;
- l2_table = NULL;
l1_size2 = l1_size * sizeof(uint64_t);
- inc_refcounts(bs, refcount_table, refcount_table_size,
+ /* Mark L1 table as used */
+ errors += inc_refcounts(bs, refcount_table, refcount_table_size,
l1_table_offset, l1_size2);
+ /* Read L1 table entries from disk */
l1_table = qemu_malloc(l1_size2);
- if (!l1_table)
- goto fail;
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]);
- l2_size = s->l2_size * sizeof(uint64_t);
- l2_table = qemu_malloc(l2_size);
- if (!l2_table)
- goto fail;
+ /* Do the actual checks */
for(i = 0; i < l1_size; i++) {
l2_offset = l1_table[i];
if (l2_offset) {
+ /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
if (check_copied) {
- refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits);
+ refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED)
+ >> s->cluster_bits);
if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) {
- printf("ERROR OFLAG_COPIED: l2_offset=%llx refcount=%d\n",
- l2_offset, refcount);
+ fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64
+ " refcount=%d\n", l2_offset, refcount);
+ errors++;
}
}
+
+ /* Mark L2 table as used */
l2_offset &= ~QCOW_OFLAG_COPIED;
- if (bdrv_pread(s->hd, 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 != 0) {
- if (offset & QCOW_OFLAG_COMPRESSED) {
- if (offset & QCOW_OFLAG_COPIED) {
- printf("ERROR: cluster %lld: copied flag must never be set for compressed clusters\n",
- offset >> s->cluster_bits);
- offset &= ~QCOW_OFLAG_COPIED;
- }
- nb_csectors = ((offset >> s->csize_shift) &
- s->csize_mask) + 1;
- offset &= s->cluster_offset_mask;
- inc_refcounts(bs, refcount_table,
- refcount_table_size,
- offset & ~511, nb_csectors * 512);
- } else {
- if (check_copied) {
- refcount = get_refcount(bs, (offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits);
- if ((refcount == 1) != ((offset & QCOW_OFLAG_COPIED) != 0)) {
- printf("ERROR OFLAG_COPIED: offset=%llx refcount=%d\n",
- offset, refcount);
- }
- }
- offset &= ~QCOW_OFLAG_COPIED;
- inc_refcounts(bs, refcount_table,
- refcount_table_size,
- offset, s->cluster_size);
- }
- }
- }
- inc_refcounts(bs, refcount_table,
+ errors += inc_refcounts(bs, 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++;
+ }
+
+ /* Process and check L2 entries */
+ ret = check_refcounts_l2(bs, refcount_table, refcount_table_size,
+ l2_offset, check_copied);
+ if (ret < 0) {
+ goto fail;
+ }
+ errors += ret;
}
}
qemu_free(l1_table);
- qemu_free(l2_table);
- return 0;
- fail:
- printf("ERROR: I/O error in check_refcounts_l1\n");
+ return errors;
+
+fail:
+ fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
qemu_free(l1_table);
- qemu_free(l2_table);
return -EIO;
}
-static void check_refcounts(BlockDriverState *bs)
+/*
+ * 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 occured.
+ */
+static int check_refcounts(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
int64_t size;
int nb_clusters, refcount1, refcount2, i;
QCowSnapshot *sn;
uint16_t *refcount_table;
+ int ret, errors = 0;
size = bdrv_getlength(s->hd);
- nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
+ nb_clusters = size_to_clusters(s, size);
refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t));
/* header */
- inc_refcounts(bs, refcount_table, nb_clusters,
+ errors += inc_refcounts(bs, refcount_table, nb_clusters,
0, s->cluster_size);
- check_refcounts_l1(bs, refcount_table, nb_clusters,
+ /* current L1 table */
+ ret = check_refcounts_l1(bs, 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++) {
check_refcounts_l1(bs, refcount_table, nb_clusters,
sn->l1_table_offset, sn->l1_size, 0);
}
- inc_refcounts(bs, refcount_table, nb_clusters,
+ errors += inc_refcounts(bs, refcount_table, nb_clusters,
s->snapshots_offset, s->snapshots_size);
/* refcount data */
- inc_refcounts(bs, refcount_table, nb_clusters,
+ errors += inc_refcounts(bs, 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;
offset = s->refcount_table[i];
if (offset != 0) {
- inc_refcounts(bs, refcount_table, nb_clusters,
+ errors += inc_refcounts(bs, refcount_table, nb_clusters,
offset, s->cluster_size);
}
}
for(i = 0; i < nb_clusters; i++) {
refcount1 = get_refcount(bs, i);
refcount2 = refcount_table[i];
- if (refcount1 != refcount2)
- printf("ERROR cluster %d refcount=%d reference=%d\n",
+ if (refcount1 != refcount2) {
+ fprintf(stderr, "ERROR cluster %d refcount=%d reference=%d\n",
i, refcount1, refcount2);
+ errors++;
+ }
}
qemu_free(refcount_table);
+
+ return errors;
+}
+
+static int qcow_check(BlockDriverState *bs)
+{
+ return check_refcounts(bs);
}
#if 0
int refcount;
size = bdrv_getlength(s->hd);
- nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
+ nb_clusters = size_to_clusters(s, size);
for(k = 0; k < nb_clusters;) {
k1 = k;
refcount = get_refcount(bs, k);
}
}
#endif
-#endif
+
+static int qcow_put_buffer(BlockDriverState *bs, const uint8_t *buf,
+ int64_t pos, int size)
+{
+ int growable = bs->growable;
+
+ bs->growable = 1;
+ bdrv_pwrite(bs, pos, buf, size);
+ bs->growable = growable;
+
+ return size;
+}
+
+static int qcow_get_buffer(BlockDriverState *bs, uint8_t *buf,
+ int64_t pos, int size)
+{
+ int growable = bs->growable;
+ int ret;
+
+ bs->growable = 1;
+ ret = bdrv_pread(bs, pos, buf, size);
+ bs->growable = growable;
+
+ return ret;
+}
BlockDriver bdrv_qcow2 = {
- "qcow2",
- sizeof(BDRVQcowState),
- qcow_probe,
- qcow_open,
- NULL,
- NULL,
- qcow_close,
- qcow_create,
- qcow_flush,
- qcow_is_allocated,
- qcow_set_key,
- qcow_make_empty,
-
- .bdrv_aio_read = qcow_aio_read,
- .bdrv_aio_write = qcow_aio_write,
- .bdrv_aio_cancel = qcow_aio_cancel,
- .aiocb_size = sizeof(QCowAIOCB),
+ .format_name = "qcow2",
+ .instance_size = sizeof(BDRVQcowState),
+ .bdrv_probe = qcow_probe,
+ .bdrv_open = qcow_open,
+ .bdrv_close = qcow_close,
+ .bdrv_create = qcow_create,
+ .bdrv_flush = qcow_flush,
+ .bdrv_is_allocated = qcow_is_allocated,
+ .bdrv_set_key = qcow_set_key,
+ .bdrv_make_empty = qcow_make_empty,
+
+ .bdrv_aio_readv = qcow_aio_readv,
+ .bdrv_aio_writev = qcow_aio_writev,
+ .bdrv_aio_cancel = qcow_aio_cancel,
+ .aiocb_size = sizeof(QCowAIOCB),
.bdrv_write_compressed = qcow_write_compressed,
.bdrv_snapshot_create = qcow_snapshot_create,
- .bdrv_snapshot_goto = qcow_snapshot_goto,
+ .bdrv_snapshot_goto = qcow_snapshot_goto,
.bdrv_snapshot_delete = qcow_snapshot_delete,
- .bdrv_snapshot_list = qcow_snapshot_list,
- .bdrv_get_info = qcow_get_info,
+ .bdrv_snapshot_list = qcow_snapshot_list,
+ .bdrv_get_info = qcow_get_info,
+
+ .bdrv_put_buffer = qcow_put_buffer,
+ .bdrv_get_buffer = qcow_get_buffer,
+
+ .bdrv_create2 = qcow_create2,
+ .bdrv_check = qcow_check,
};