#include "block_int.h"
#include "block/qcow2.h"
-int qcow2_grow_l1_table(BlockDriverState *bs, int min_size)
+int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size)
{
BDRVQcowState *s = bs->opaque;
int new_l1_size, new_l1_size2, ret, i;
uint64_t *new_l1_table;
- uint64_t new_l1_table_offset;
+ int64_t new_l1_table_offset;
uint8_t data[12];
- new_l1_size = s->l1_size;
- if (min_size <= new_l1_size)
+ if (min_size <= s->l1_size)
return 0;
- if (new_l1_size == 0) {
- new_l1_size = 1;
- }
- while (min_size > new_l1_size) {
- new_l1_size = (new_l1_size * 3 + 1) / 2;
+
+ if (exact_size) {
+ new_l1_size = min_size;
+ } else {
+ /* Bump size up to reduce the number of times we have to grow */
+ new_l1_size = s->l1_size;
+ if (new_l1_size == 0) {
+ new_l1_size = 1;
+ }
+ while (min_size > new_l1_size) {
+ new_l1_size = (new_l1_size * 3 + 1) / 2;
+ }
}
+
#ifdef DEBUG_ALLOC2
- printf("grow l1_table from %d to %d\n", s->l1_size, new_l1_size);
+ fprintf(stderr, "grow l1_table from %d to %d\n", s->l1_size, new_l1_size);
#endif
new_l1_size2 = sizeof(uint64_t) * new_l1_size;
- new_l1_table = qemu_mallocz(align_offset(new_l1_size2, 512));
+ new_l1_table = g_malloc0(align_offset(new_l1_size2, 512));
memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
/* write new table (align to cluster) */
+ BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE);
new_l1_table_offset = qcow2_alloc_clusters(bs, new_l1_size2);
+ if (new_l1_table_offset < 0) {
+ g_free(new_l1_table);
+ return new_l1_table_offset;
+ }
+ ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE);
for(i = 0; i < s->l1_size; i++)
new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
- ret = bdrv_pwrite(s->hd, new_l1_table_offset, new_l1_table, new_l1_size2);
- if (ret != new_l1_size2)
+ ret = bdrv_pwrite_sync(bs->file, new_l1_table_offset, new_l1_table, new_l1_size2);
+ if (ret < 0)
goto fail;
for(i = 0; i < s->l1_size; i++)
new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
/* set new table */
+ BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ACTIVATE_TABLE);
cpu_to_be32w((uint32_t*)data, new_l1_size);
- cpu_to_be64w((uint64_t*)(data + 4), new_l1_table_offset);
- ret = bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_size), data,sizeof(data));
- if (ret != sizeof(data)) {
+ cpu_to_be64wu((uint64_t*)(data + 4), new_l1_table_offset);
+ ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_size), data,sizeof(data));
+ if (ret < 0) {
goto fail;
}
- qemu_free(s->l1_table);
+ g_free(s->l1_table);
qcow2_free_clusters(bs, s->l1_table_offset, s->l1_size * sizeof(uint64_t));
s->l1_table_offset = new_l1_table_offset;
s->l1_table = new_l1_table;
s->l1_size = new_l1_size;
return 0;
fail:
- qemu_free(new_l1_table);
+ g_free(new_l1_table);
qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2);
- return ret < 0 ? ret : -EIO;
-}
-
-void qcow2_l2_cache_reset(BlockDriverState *bs)
-{
- BDRVQcowState *s = bs->opaque;
-
- memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
- memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
- memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
-}
-
-static inline int l2_cache_new_entry(BlockDriverState *bs)
-{
- BDRVQcowState *s = bs->opaque;
- uint32_t min_count;
- int min_index, i;
-
- /* find a new entry in the least used one */
- min_index = 0;
- min_count = 0xffffffff;
- for(i = 0; i < L2_CACHE_SIZE; i++) {
- if (s->l2_cache_counts[i] < min_count) {
- min_count = s->l2_cache_counts[i];
- min_index = i;
- }
- }
- return min_index;
-}
-
-/*
- * seek_l2_table
- *
- * 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
- *
- */
-
-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;
+ return ret;
}
/*
* the image file failed.
*/
-static uint64_t *l2_load(BlockDriverState *bs, uint64_t l2_offset)
+static int l2_load(BlockDriverState *bs, uint64_t l2_offset,
+ uint64_t **l2_table)
{
BDRVQcowState *s = bs->opaque;
- int min_index;
- uint64_t *l2_table;
-
- /* seek if the table for the given offset is in the cache */
-
- 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 */
+ int ret;
- 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;
+ ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, (void**) l2_table);
- return l2_table;
+ return ret;
}
/*
* and we really don't want bdrv_pread to perform a read-modify-write)
*/
#define L1_ENTRIES_PER_SECTOR (512 / 8)
-static int write_l1_entry(BDRVQcowState *s, int l1_index)
+static int write_l1_entry(BlockDriverState *bs, int l1_index)
{
+ BDRVQcowState *s = bs->opaque;
uint64_t buf[L1_ENTRIES_PER_SECTOR];
int l1_start_index;
- int i;
+ int i, ret;
l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1);
for (i = 0; i < L1_ENTRIES_PER_SECTOR; i++) {
buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
}
- if (bdrv_pwrite(s->hd, s->l1_table_offset + 8 * l1_start_index,
- buf, sizeof(buf)) != sizeof(buf))
- {
- return -1;
+ BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
+ ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset + 8 * l1_start_index,
+ buf, sizeof(buf));
+ if (ret < 0) {
+ return ret;
}
return 0;
*
*/
-static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index)
+static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table)
{
BDRVQcowState *s = bs->opaque;
- int min_index;
uint64_t old_l2_offset;
- uint64_t *l2_table, l2_offset;
+ uint64_t *l2_table;
+ int64_t l2_offset;
+ int ret;
old_l2_offset = s->l1_table[l1_index];
/* allocate a new l2 entry */
l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
+ if (l2_offset < 0) {
+ return l2_offset;
+ }
- /* update the L1 entry */
-
- s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
- if (write_l1_entry(s, l1_index) < 0) {
- return NULL;
+ ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+ if (ret < 0) {
+ goto fail;
}
/* 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);
+ ret = qcow2_cache_get_empty(bs, s->l2_table_cache, l2_offset, (void**) table);
+ if (ret < 0) {
+ return ret;
+ }
+
+ l2_table = *table;
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 {
+ uint64_t* old_table;
+
/* 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 NULL;
+ BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ);
+ ret = qcow2_cache_get(bs, s->l2_table_cache, old_l2_offset,
+ (void**) &old_table);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ memcpy(l2_table, old_table, s->cluster_size);
+
+ ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &old_table);
+ if (ret < 0) {
+ goto fail;
+ }
}
+
/* 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;
+ BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE);
- /* update the l2 cache entry */
+ qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
+ ret = qcow2_cache_flush(bs, s->l2_table_cache);
+ if (ret < 0) {
+ goto fail;
+ }
- s->l2_cache_offsets[min_index] = l2_offset;
- s->l2_cache_counts[min_index] = 1;
+ /* update the L1 entry */
+ s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
+ ret = write_l1_entry(bs, l1_index);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ *table = l2_table;
+ return 0;
- return l2_table;
+fail:
+ qcow2_cache_put(bs, s->l2_table_cache, (void**) table);
+ s->l1_table[l1_index] = old_l2_offset;
+ return ret;
}
static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size,
}
-static int qcow_read(BlockDriverState *bs, int64_t sector_num,
- uint8_t *buf, int nb_sectors)
+static int qcow2_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
{
BDRVQcowState *s = bs->opaque;
int ret, index_in_cluster, n, n1;
uint64_t cluster_offset;
+ struct iovec iov;
+ QEMUIOVector qiov;
while (nb_sectors > 0) {
n = nb_sectors;
- cluster_offset = qcow2_get_cluster_offset(bs, sector_num << 9, &n);
+
+ ret = qcow2_get_cluster_offset(bs, sector_num << 9, &n,
+ &cluster_offset);
+ if (ret < 0) {
+ return ret;
+ }
+
index_in_cluster = sector_num & (s->cluster_sectors - 1);
if (!cluster_offset) {
if (bs->backing_hd) {
/* read from the base image */
- n1 = qcow2_backing_read1(bs->backing_hd, sector_num, buf, n);
+ iov.iov_base = buf;
+ iov.iov_len = n * 512;
+ qemu_iovec_init_external(&qiov, &iov, 1);
+
+ n1 = qcow2_backing_read1(bs->backing_hd, &qiov, sector_num, n);
if (n1 > 0) {
+ BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING);
ret = bdrv_read(bs->backing_hd, sector_num, buf, n1);
if (ret < 0)
return -1;
memset(buf, 0, 512 * n);
}
} else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
- if (qcow2_decompress_cluster(s, cluster_offset) < 0)
+ if (qcow2_decompress_cluster(bs, cluster_offset) < 0)
return -1;
memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
} else {
- ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
+ BLKDBG_EVENT(bs->file, BLKDBG_READ);
+ ret = bdrv_pread(bs->file, cluster_offset + index_in_cluster * 512, buf, n * 512);
if (ret != n * 512)
return -1;
if (s->crypt_method) {
n = n_end - n_start;
if (n <= 0)
return 0;
- ret = qcow_read(bs, start_sect + n_start, s->cluster_data, n);
+ BLKDBG_EVENT(bs->file, BLKDBG_COW_READ);
+ ret = qcow2_read(bs, start_sect + n_start, s->cluster_data, n);
if (ret < 0)
return ret;
if (s->crypt_method) {
s->cluster_data, n, 1,
&s->aes_encrypt_key);
}
- ret = bdrv_write(s->hd, (cluster_offset >> 9) + n_start,
- s->cluster_data, n);
+ BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
+ ret = bdrv_write(bs->file, (cluster_offset >> 9) + n_start,
+ s->cluster_data, n);
if (ret < 0)
return ret;
return 0;
/*
* get_cluster_offset
*
- * For a given offset of the disk image, return cluster offset in
- * qcow2 file.
+ * For a given offset of the disk image, find the cluster offset in
+ * qcow2 file. The offset is stored in *cluster_offset.
*
- * on entry, *num is the number of contiguous clusters we'd like to
+ * on entry, *num is the number of contiguous sectors we'd like to
* access following offset.
*
- * on exit, *num is the number of contiguous clusters we can read.
+ * on exit, *num is the number of contiguous sectors we can read.
*
- * Return 1, if the offset is found
- * Return 0, otherwise.
+ * Return 0, if the offset is found
+ * Return -errno, otherwise.
*
*/
-uint64_t qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
- int *num)
+int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
+ int *num, uint64_t *cluster_offset)
{
BDRVQcowState *s = bs->opaque;
unsigned int l1_index, l2_index;
- uint64_t l2_offset, *l2_table, cluster_offset;
+ uint64_t l2_offset, *l2_table;
int l1_bits, c;
unsigned int index_in_cluster, nb_clusters;
uint64_t nb_available, nb_needed;
+ int ret;
index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1);
nb_needed = *num + index_in_cluster;
nb_needed = nb_available;
}
- cluster_offset = 0;
+ *cluster_offset = 0;
/* seek the the l2 offset in the l1 table */
/* load the l2 table in memory */
l2_offset &= ~QCOW_OFLAG_COPIED;
- l2_table = l2_load(bs, l2_offset);
- if (l2_table == NULL)
- return 0;
+ ret = l2_load(bs, l2_offset, &l2_table);
+ if (ret < 0) {
+ return ret;
+ }
/* 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]);
+ *cluster_offset = be64_to_cpu(l2_table[l2_index]);
nb_clusters = size_to_clusters(s, nb_needed << 9);
- if (!cluster_offset) {
+ if (!*cluster_offset) {
/* how many empty clusters ? */
c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]);
} else {
&l2_table[l2_index], 0, QCOW_OFLAG_COPIED);
}
+ qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+
nb_available = (c * s->cluster_sectors);
out:
if (nb_available > nb_needed)
*num = nb_available - index_in_cluster;
- return cluster_offset & ~QCOW_OFLAG_COPIED;
+ *cluster_offset &=~QCOW_OFLAG_COPIED;
+ return 0;
}
/*
{
BDRVQcowState *s = bs->opaque;
unsigned int l1_index, l2_index;
- uint64_t l2_offset, *l2_table;
+ uint64_t l2_offset;
+ uint64_t *l2_table = NULL;
int ret;
/* 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 = qcow2_grow_l1_table(bs, l1_index + 1);
+ ret = qcow2_grow_l1_table(bs, l1_index + 1, false);
if (ret < 0) {
return ret;
}
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 -EIO;
+ ret = l2_load(bs, l2_offset, &l2_table);
+ if (ret < 0) {
+ return ret;
}
} else {
- if (l2_offset)
+ /* First allocate a new L2 table (and do COW if needed) */
+ ret = l2_allocate(bs, l1_index, &l2_table);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* Then decrease the refcount of the old table */
+ if (l2_offset) {
qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
- l2_table = l2_allocate(bs, l1_index);
- if (l2_table == NULL) {
- return -EIO;
}
l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED;
}
{
BDRVQcowState *s = bs->opaque;
int l2_index, ret;
- uint64_t l2_offset, *l2_table, cluster_offset;
+ uint64_t l2_offset, *l2_table;
+ int64_t cluster_offset;
int nb_csectors;
ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
qcow2_free_any_clusters(bs, cluster_offset, 1);
cluster_offset = qcow2_alloc_bytes(bs, compressed_size);
+ if (cluster_offset < 0) {
+ qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+ return 0;
+ }
+
nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
(cluster_offset >> 9);
/* compressed clusters never have the copied flag */
+ BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
+ qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
l2_table[l2_index] = cpu_to_be64(cluster_offset);
- if (bdrv_pwrite(s->hd,
- l2_offset + l2_index * sizeof(uint64_t),
- l2_table + l2_index,
- sizeof(uint64_t)) != sizeof(uint64_t))
+ ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+ if (ret < 0) {
return 0;
-
- return cluster_offset;
-}
-
-/*
- * Write L2 table updates to disk, writing whole sectors to avoid a
- * read-modify-write in bdrv_pwrite
- */
-#define L2_ENTRIES_PER_SECTOR (512 / 8)
-static int write_l2_entries(BDRVQcowState *s, uint64_t *l2_table,
- uint64_t l2_offset, int l2_index, int num)
-{
- int l2_start_index = l2_index & ~(L1_ENTRIES_PER_SECTOR - 1);
- int start_offset = (8 * l2_index) & ~511;
- int end_offset = (8 * (l2_index + num) + 511) & ~511;
- size_t len = end_offset - start_offset;
-
- if (bdrv_pwrite(s->hd, l2_offset + start_offset, &l2_table[l2_start_index],
- len) != len)
- {
- return -1;
}
- return 0;
+ return cluster_offset;
}
-int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, uint64_t cluster_offset,
- QCowL2Meta *m)
+int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
{
BDRVQcowState *s = bs->opaque;
int i, j = 0, l2_index, ret;
uint64_t *old_cluster, start_sect, l2_offset, *l2_table;
+ uint64_t cluster_offset = m->cluster_offset;
+ bool cow = false;
if (m->nb_clusters == 0)
return 0;
- old_cluster = qemu_malloc(m->nb_clusters * sizeof(uint64_t));
+ old_cluster = g_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) {
+ cow = true;
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);
+ cow = true;
ret = copy_sectors(bs, start_sect + end, cluster_offset + (end << 9),
m->nb_available - end, s->cluster_sectors);
if (ret < 0)
goto err;
}
- /* update L2 table */
+ /*
+ * Update L2 table.
+ *
+ * Before we update the L2 table to actually point to the new cluster, we
+ * need to be sure that the refcounts have been increased and COW was
+ * handled.
+ */
+ if (cow) {
+ qcow2_cache_depends_on_flush(s->l2_table_cache);
+ }
+
+ qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache);
ret = get_cluster_table(bs, m->offset, &l2_table, &l2_offset, &l2_index);
if (ret < 0) {
goto err;
}
+ qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
for (i = 0; i < m->nb_clusters; i++) {
/* if two concurrent writes happen to the same unallocated cluster
(i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
}
- if (write_l2_entries(s, l2_table, l2_offset, l2_index, m->nb_clusters) < 0) {
- ret = -1;
+
+ ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+ if (ret < 0) {
goto err;
}
- for (i = 0; i < j; i++)
- qcow2_free_any_clusters(bs,
- be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1);
+ /*
+ * If this was a COW, we need to decrease the refcount of the old cluster.
+ * Also flush bs->file to get the right order for L2 and refcount update.
+ */
+ if (j != 0) {
+ for (i = 0; i < j; i++) {
+ qcow2_free_any_clusters(bs,
+ be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1);
+ }
+ }
ret = 0;
err:
- qemu_free(old_cluster);
+ g_free(old_cluster);
return ret;
}
/*
* alloc_cluster_offset
*
- * For a given offset of the disk image, return cluster offset in
- * qcow2 file.
- *
+ * 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.
+ * If the cluster was already allocated, m->nb_clusters is set to 0,
+ * m->depends_on is set to NULL and the other fields in m are meaningless.
+ *
+ * If the cluster is newly allocated, m->nb_clusters is set to the number of
+ * contiguous clusters that have been allocated. In this case, the other
+ * fields of m are valid and contain information about the first allocated
+ * cluster.
+ *
+ * If the request conflicts with another write request in flight, the coroutine
+ * is queued and will be reentered when the dependency has completed.
*
+ * Return 0 on success and -errno in error cases
*/
-
-uint64_t qcow2_alloc_cluster_offset(BlockDriverState *bs,
- uint64_t offset,
- int n_start, int n_end,
- int *num, QCowL2Meta *m)
+int qcow2_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;
+ uint64_t l2_offset, *l2_table;
+ int64_t cluster_offset;
unsigned int nb_clusters, i = 0;
QCowL2Meta *old_alloc;
ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
if (ret < 0) {
- return 0;
+ return ret;
}
+again:
nb_clusters = size_to_clusters(s, n_end << 9);
nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
cluster_offset &= ~QCOW_OFLAG_COPIED;
m->nb_clusters = 0;
+ m->depends_on = NULL;
goto out;
}
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]))
+ if ((i >= nb_clusters) || be64_to_cpu(l2_table[l2_index + i])) {
break;
+ }
i += count_contiguous_free_clusters(nb_clusters - i,
&l2_table[l2_index + i]);
+ if (i >= nb_clusters) {
+ break;
+ }
cluster_offset = be64_to_cpu(l2_table[l2_index + i]);
(cluster_offset & QCOW_OFLAG_COMPRESSED))
break;
}
+ assert(i <= nb_clusters);
nb_clusters = i;
/*
}
if (nb_clusters == 0) {
- /* Set dependency and wait for a callback */
- m->depends_on = old_alloc;
- m->nb_clusters = 0;
- *num = 0;
- return 0;
+ /* Wait for the dependency to complete. We need to recheck
+ * the free/allocated clusters when we continue. */
+ qemu_co_mutex_unlock(&s->lock);
+ qemu_co_queue_wait(&old_alloc->dependent_requests);
+ qemu_co_mutex_lock(&s->lock);
+ goto again;
}
}
}
/* allocate a new cluster */
cluster_offset = qcow2_alloc_clusters(bs, nb_clusters * s->cluster_size);
+ if (cluster_offset < 0) {
+ ret = cluster_offset;
+ goto fail;
+ }
/* save info needed for meta data update */
m->offset = offset;
m->nb_clusters = nb_clusters;
out:
+ ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+ if (ret < 0) {
+ goto fail_put;
+ }
+
m->nb_available = MIN(nb_clusters << (s->cluster_bits - 9), n_end);
+ m->cluster_offset = cluster_offset;
*num = m->nb_available - n_start;
- return cluster_offset;
+ return 0;
+
+fail:
+ qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+fail_put:
+ QLIST_REMOVE(m, next_in_flight);
+ return ret;
}
static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
return 0;
}
-int qcow2_decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
+int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
{
+ BDRVQcowState *s = bs->opaque;
int ret, csize, nb_csectors, sector_offset;
uint64_t coffset;
nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
sector_offset = coffset & 511;
csize = nb_csectors * 512 - sector_offset;
- ret = bdrv_read(s->hd, coffset >> 9, s->cluster_data, nb_csectors);
+ BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
+ ret = bdrv_read(bs->file, coffset >> 9, s->cluster_data, nb_csectors);
if (ret < 0) {
- return -1;
+ return ret;
}
if (decompress_buffer(s->cluster_cache, s->cluster_size,
s->cluster_data + sector_offset, csize) < 0) {
- return -1;
+ return -EIO;
}
s->cluster_cache_offset = coffset;
}
return 0;
}
+
+/*
+ * This discards as many clusters of nb_clusters as possible at once (i.e.
+ * all clusters in the same L2 table) and returns the number of discarded
+ * clusters.
+ */
+static int discard_single_l2(BlockDriverState *bs, uint64_t offset,
+ unsigned int nb_clusters)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t l2_offset, *l2_table;
+ int l2_index;
+ int ret;
+ int i;
+
+ ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* Limit nb_clusters to one L2 table */
+ nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
+
+ for (i = 0; i < nb_clusters; i++) {
+ uint64_t old_offset;
+
+ old_offset = be64_to_cpu(l2_table[l2_index + i]);
+ old_offset &= ~QCOW_OFLAG_COPIED;
+
+ if (old_offset == 0) {
+ continue;
+ }
+
+ /* First remove L2 entries */
+ qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
+ l2_table[l2_index + i] = cpu_to_be64(0);
+
+ /* Then decrease the refcount */
+ qcow2_free_any_clusters(bs, old_offset, 1);
+ }
+
+ ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+ if (ret < 0) {
+ return ret;
+ }
+
+ return nb_clusters;
+}
+
+int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
+ int nb_sectors)
+{
+ BDRVQcowState *s = bs->opaque;
+ uint64_t end_offset;
+ unsigned int nb_clusters;
+ int ret;
+
+ end_offset = offset + (nb_sectors << BDRV_SECTOR_BITS);
+
+ /* Round start up and end down */
+ offset = align_offset(offset, s->cluster_size);
+ end_offset &= ~(s->cluster_size - 1);
+
+ if (offset > end_offset) {
+ return 0;
+ }
+
+ nb_clusters = size_to_clusters(s, end_offset - offset);
+
+ /* Each L2 table is handled by its own loop iteration */
+ while (nb_clusters > 0) {
+ ret = discard_single_l2(bs, offset, nb_clusters);
+ if (ret < 0) {
+ return ret;
+ }
+
+ nb_clusters -= ret;
+ offset += (ret * s->cluster_size);
+ }
+
+ return 0;
+}
projects / qemu.git / blobdiff