#include "block/block_int.h"
#include "qemu/module.h"
#include "migration/migration.h"
+#include "block/coroutine.h"
#if defined(CONFIG_UUID)
#include <uuid/uuid.h>
#define VDI_IS_ALLOCATED(X) ((X) < VDI_DISCARDED)
-/* max blocks in image is (0xffffffff / 4) */
-#define VDI_BLOCKS_IN_IMAGE_MAX 0x3fffffff
+/* The bmap will take up VDI_BLOCKS_IN_IMAGE_MAX * sizeof(uint32_t) bytes; since
+ * the bmap is read and written in a single operation, its size needs to be
+ * limited to INT_MAX; furthermore, when opening an image, the bmap size is
+ * rounded up to be aligned on BDRV_SECTOR_SIZE.
+ * Therefore this should satisfy the following:
+ * VDI_BLOCKS_IN_IMAGE_MAX * sizeof(uint32_t) + BDRV_SECTOR_SIZE == INT_MAX + 1
+ * (INT_MAX + 1 is the first value not representable as an int)
+ * This guarantees that any value below or equal to the constant will, when
+ * multiplied by sizeof(uint32_t) and rounded up to a BDRV_SECTOR_SIZE boundary,
+ * still be below or equal to INT_MAX. */
+#define VDI_BLOCKS_IN_IMAGE_MAX \
+ ((unsigned)((INT_MAX + 1u - BDRV_SECTOR_SIZE) / sizeof(uint32_t)))
#define VDI_DISK_SIZE_MAX ((uint64_t)VDI_BLOCKS_IN_IMAGE_MAX * \
(uint64_t)DEFAULT_CLUSTER_SIZE)
return memcmp(uu, null_uuid, sizeof(uuid_t)) == 0;
}
+# if defined(CONFIG_VDI_DEBUG)
static inline void uuid_unparse(const uuid_t uu, char *out)
{
snprintf(out, 37, UUID_FMT,
uu[0], uu[1], uu[2], uu[3], uu[4], uu[5], uu[6], uu[7],
uu[8], uu[9], uu[10], uu[11], uu[12], uu[13], uu[14], uu[15]);
}
+# endif
#endif
typedef struct {
/* VDI header (converted to host endianness). */
VdiHeader header;
+ CoMutex write_lock;
+
Error *migration_blocker;
} BDRVVdiState;
return -ENOTSUP;
}
- bmap = g_try_malloc(s->header.blocks_in_image * sizeof(uint32_t));
+ bmap = g_try_new(uint32_t, s->header.blocks_in_image);
if (s->header.blocks_in_image && bmap == NULL) {
res->check_errors++;
return -ENOMEM;
We accept them but round the disk size to the next multiple of
SECTOR_SIZE. */
logout("odd disk size %" PRIu64 " B, round up\n", header.disk_size);
- header.disk_size += SECTOR_SIZE - 1;
- header.disk_size &= ~(SECTOR_SIZE - 1);
+ header.disk_size = ROUND_UP(header.disk_size, SECTOR_SIZE);
}
if (header.signature != VDI_SIGNATURE) {
s->header = header;
bmap_size = header.blocks_in_image * sizeof(uint32_t);
- bmap_size = (bmap_size + SECTOR_SIZE - 1) / SECTOR_SIZE;
+ bmap_size = DIV_ROUND_UP(bmap_size, SECTOR_SIZE);
s->bmap = qemu_try_blockalign(bs->file, bmap_size * SECTOR_SIZE);
if (s->bmap == NULL) {
ret = -ENOMEM;
}
/* Disable migration when vdi images are used */
- error_set(&s->migration_blocker,
- QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
- "vdi", bs->device_name, "live migration");
+ error_setg(&s->migration_blocker, "The vdi format used by node '%s' "
+ "does not support live migration",
+ bdrv_get_device_or_node_name(bs));
migrate_add_blocker(s->migration_blocker);
+ qemu_co_mutex_init(&s->write_lock);
+
return 0;
fail_free_bmap:
buf, n_sectors * SECTOR_SIZE);
memset(block + (sector_in_block + n_sectors) * SECTOR_SIZE, 0,
(s->block_sectors - n_sectors - sector_in_block) * SECTOR_SIZE);
+
+ /* Note that this coroutine does not yield anywhere from reading the
+ * bmap entry until here, so in regards to all the coroutines trying
+ * to write to this cluster, the one doing the allocation will
+ * always be the first to try to acquire the lock.
+ * Therefore, it is also the first that will actually be able to
+ * acquire the lock and thus the padded cluster is written before
+ * the other coroutines can write to the affected area. */
+ qemu_co_mutex_lock(&s->write_lock);
ret = bdrv_write(bs->file, offset, block, s->block_sectors);
+ qemu_co_mutex_unlock(&s->write_lock);
} else {
uint64_t offset = s->header.offset_data / SECTOR_SIZE +
(uint64_t)bmap_entry * s->block_sectors +
sector_in_block;
+ qemu_co_mutex_lock(&s->write_lock);
+ /* This lock is only used to make sure the following write operation
+ * is executed after the write issued by the coroutine allocating
+ * this cluster, therefore we do not need to keep it locked.
+ * As stated above, the allocating coroutine will always try to lock
+ * the mutex before all the other concurrent accesses to that
+ * cluster, therefore at this point we can be absolutely certain
+ * that that write operation has returned (there may be other writes
+ * in flight, but they do not concern this very operation). */
+ qemu_co_mutex_unlock(&s->write_lock);
ret = bdrv_write(bs->file, offset, buf, n_sectors);
}
logout("\n");
/* Read out options. */
- bytes = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
+ bytes = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
+ BDRV_SECTOR_SIZE);
#if defined(CONFIG_VDI_BLOCK_SIZE)
/* TODO: Additional checks (SECTOR_SIZE * 2^n, ...). */
block_size = qemu_opt_get_size_del(opts,
/* We need enough blocks to store the given disk size,
so always round up. */
- blocks = (bytes + block_size - 1) / block_size;
+ blocks = DIV_ROUND_UP(bytes, block_size);
bmap_size = blocks * sizeof(uint32_t);
- bmap_size = ((bmap_size + SECTOR_SIZE - 1) & ~(SECTOR_SIZE -1));
+ bmap_size = ROUND_UP(bmap_size, SECTOR_SIZE);
memset(&header, 0, sizeof(header));
pstrcpy(header.text, sizeof(header.text), VDI_TEXT);
.def_value_str = "off"
},
#endif
- {
- .name = BLOCK_OPT_NOCOW,
- .type = QEMU_OPT_BOOL,
- .help = "Turn off copy-on-write (valid only on btrfs)"
- },
/* TODO: An additional option to set UUID values might be useful. */
{ /* end of list */ }
}
projects / qemu.git / blobdiff