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vpc: Implement .bdrv_co_preadv() interface 

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
master
Kevin Wolf 2016-04-26 16:24:46 +02:00
parent 37b1d7d8c9
commit d46b7cc680
1 changed files with 42 additions and 37 deletions
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79
block/vpc.c
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@ -454,22 +454,21 @@ static int vpc_reopen_prepare(BDRVReopenState *state,
* The parameter write must be 1 if the offset will be used for a write
* operation (the block bitmaps is updated then), 0 otherwise.
*/
static inline int64_t get_sector_offset(BlockDriverState *bs,
int64_t sector_num, int write)
static inline int64_t get_image_offset(BlockDriverState *bs, uint64_t offset,
bool write)
{
BDRVVPCState *s = bs->opaque;
uint64_t offset = sector_num * 512;
uint64_t bitmap_offset, block_offset;
uint32_t pagetable_index, pageentry_index;
uint32_t pagetable_index, offset_in_block;
pagetable_index = offset / s->block_size;
pageentry_index = (offset % s->block_size) / 512;
offset_in_block = offset % s->block_size;
if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff)
return -1; /* not allocated */
bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index];
block_offset = bitmap_offset + s->bitmap_size + (512 * pageentry_index);
block_offset = bitmap_offset + s->bitmap_size + offset_in_block;
/* We must ensure that we don't write to any sectors which are marked as
unused in the bitmap. We get away with setting all bits in the block
@ -487,6 +486,12 @@ static inline int64_t get_sector_offset(BlockDriverState *bs,
return block_offset;
}
static inline int64_t get_sector_offset(BlockDriverState *bs,
int64_t sector_num, bool write)
{
return get_image_offset(bs, sector_num * BDRV_SECTOR_SIZE, write);
}
/*
* Writes the footer to the end of the image file. This is needed when the
* file grows as it overwrites the old footer
@ -573,52 +578,52 @@ static int vpc_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
return 0;
}
static int vpc_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
static int coroutine_fn
vpc_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
{
BDRVVPCState *s = bs->opaque;
int ret;
int64_t offset;
int64_t sectors, sectors_per_block;
int64_t image_offset;
int64_t n_bytes;
int64_t bytes_done = 0;
VHDFooter *footer = (VHDFooter *) s->footer_buf;
QEMUIOVector local_qiov;
if (be32_to_cpu(footer->type) == VHD_FIXED) {
return bdrv_read(bs->file->bs, sector_num, buf, nb_sectors);
return bdrv_co_preadv(bs->file->bs, offset, bytes, qiov, 0);
}
while (nb_sectors > 0) {
offset = get_sector_offset(bs, sector_num, 0);
sectors_per_block = s->block_size >> BDRV_SECTOR_BITS;
sectors = sectors_per_block - (sector_num % sectors_per_block);
if (sectors > nb_sectors) {
sectors = nb_sectors;
}
qemu_co_mutex_lock(&s->lock);
qemu_iovec_init(&local_qiov, qiov->niov);
if (offset == -1) {
memset(buf, 0, sectors * BDRV_SECTOR_SIZE);
while (bytes > 0) {
image_offset = get_image_offset(bs, offset, false);
n_bytes = MIN(bytes, s->block_size - (offset % s->block_size));
if (image_offset == -1) {
qemu_iovec_memset(qiov, bytes_done, 0, n_bytes);
} else {
ret = bdrv_pread(bs->file->bs, offset, buf,
sectors * BDRV_SECTOR_SIZE);
if (ret != sectors * BDRV_SECTOR_SIZE) {
return -1;
qemu_iovec_reset(&local_qiov);
qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes);
ret = bdrv_co_preadv(bs->file->bs, image_offset, n_bytes,
&local_qiov, 0);
if (ret < 0) {
goto fail;
}
}
nb_sectors -= sectors;
sector_num += sectors;
buf += sectors * BDRV_SECTOR_SIZE;
bytes -= n_bytes;
offset += n_bytes;
bytes_done += n_bytes;
}
return 0;
}
static coroutine_fn int vpc_co_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
int ret;
BDRVVPCState *s = bs->opaque;
qemu_co_mutex_lock(&s->lock);
ret = vpc_read(bs, sector_num, buf, nb_sectors);
ret = 0;
fail:
qemu_iovec_destroy(&local_qiov);
qemu_co_mutex_unlock(&s->lock);
return ret;
}
@ -1056,7 +1061,7 @@ static BlockDriver bdrv_vpc = {
.bdrv_reopen_prepare = vpc_reopen_prepare,
.bdrv_create = vpc_create,
.bdrv_read = vpc_co_read,
.bdrv_co_preadv = vpc_co_preadv,
.bdrv_write = vpc_co_write,
.bdrv_co_get_block_status = vpc_co_get_block_status,