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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 * The parameter write must be 1 if the offset will be used for a write
* operation (the block bitmaps is updated then), 0 otherwise. * operation (the block bitmaps is updated then), 0 otherwise.
*/ */
static inline int64_t get_sector_offset(BlockDriverState *bs, static inline int64_t get_image_offset(BlockDriverState *bs, uint64_t offset,
int64_t sector_num, int write) bool write)
{ {
BDRVVPCState *s = bs->opaque; BDRVVPCState *s = bs->opaque;
uint64_t offset = sector_num * 512;
uint64_t bitmap_offset, block_offset; 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; 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) if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff)
return -1; /* not allocated */ return -1; /* not allocated */
bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index]; 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 /* 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 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; 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 * Writes the footer to the end of the image file. This is needed when the
* file grows as it overwrites the old footer * file grows as it overwrites the old footer
@ -573,52 +578,52 @@ static int vpc_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
return 0; return 0;
} }
static int vpc_read(BlockDriverState *bs, int64_t sector_num, static int coroutine_fn
uint8_t *buf, int nb_sectors) vpc_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
{ {
BDRVVPCState *s = bs->opaque; BDRVVPCState *s = bs->opaque;
int ret; int ret;
int64_t offset; int64_t image_offset;
int64_t sectors, sectors_per_block; int64_t n_bytes;
int64_t bytes_done = 0;
VHDFooter *footer = (VHDFooter *) s->footer_buf; VHDFooter *footer = (VHDFooter *) s->footer_buf;
QEMUIOVector local_qiov;
if (be32_to_cpu(footer->type) == VHD_FIXED) { 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; qemu_co_mutex_lock(&s->lock);
sectors = sectors_per_block - (sector_num % sectors_per_block); qemu_iovec_init(&local_qiov, qiov->niov);
if (sectors > nb_sectors) {
sectors = nb_sectors;
}
if (offset == -1) { while (bytes > 0) {
memset(buf, 0, sectors * BDRV_SECTOR_SIZE); 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 { } else {
ret = bdrv_pread(bs->file->bs, offset, buf, qemu_iovec_reset(&local_qiov);
sectors * BDRV_SECTOR_SIZE); qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes);
if (ret != sectors * BDRV_SECTOR_SIZE) {
return -1; ret = bdrv_co_preadv(bs->file->bs, image_offset, n_bytes,
&local_qiov, 0);
if (ret < 0) {
goto fail;
} }
} }
nb_sectors -= sectors; bytes -= n_bytes;
sector_num += sectors; offset += n_bytes;
buf += sectors * BDRV_SECTOR_SIZE; bytes_done += n_bytes;
} }
return 0;
}
static coroutine_fn int vpc_co_read(BlockDriverState *bs, int64_t sector_num, ret = 0;
uint8_t *buf, int nb_sectors) fail:
{ qemu_iovec_destroy(&local_qiov);
int ret;
BDRVVPCState *s = bs->opaque;
qemu_co_mutex_lock(&s->lock);
ret = vpc_read(bs, sector_num, buf, nb_sectors);
qemu_co_mutex_unlock(&s->lock); qemu_co_mutex_unlock(&s->lock);
return ret; return ret;
} }
@ -1056,7 +1061,7 @@ static BlockDriver bdrv_vpc = {
.bdrv_reopen_prepare = vpc_reopen_prepare, .bdrv_reopen_prepare = vpc_reopen_prepare,
.bdrv_create = vpc_create, .bdrv_create = vpc_create,
.bdrv_read = vpc_co_read, .bdrv_co_preadv = vpc_co_preadv,
.bdrv_write = vpc_co_write, .bdrv_write = vpc_co_write,
.bdrv_co_get_block_status = vpc_co_get_block_status, .bdrv_co_get_block_status = vpc_co_get_block_status,