dmg: Implement .bdrv_co_preadv() interface
This implements .bdrv_co_preadv() for the cloop block driver. While updating the error paths, change -1 to a valid -errno code. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com>
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40
block/dmg.c
40
block/dmg.c
@ -440,6 +440,8 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
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int ret;
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bs->read_only = 1;
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bs->request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O supported */
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s->n_chunks = 0;
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s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
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/* used by dmg_read_mish_block to keep track of the current I/O position */
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@ -659,38 +661,42 @@ static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num)
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return 0;
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}
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static int dmg_read(BlockDriverState *bs, int64_t sector_num,
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uint8_t *buf, int nb_sectors)
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static int coroutine_fn
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dmg_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
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QEMUIOVector *qiov, int flags)
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{
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BDRVDMGState *s = bs->opaque;
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int i;
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uint64_t sector_num = offset >> BDRV_SECTOR_BITS;
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int nb_sectors = bytes >> BDRV_SECTOR_BITS;
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int ret, i;
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assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
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assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
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qemu_co_mutex_lock(&s->lock);
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for (i = 0; i < nb_sectors; i++) {
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uint32_t sector_offset_in_chunk;
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void *data;
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if (dmg_read_chunk(bs, sector_num + i) != 0) {
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return -1;
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ret = -EIO;
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goto fail;
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}
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/* Special case: current chunk is all zeroes. Do not perform a memcpy as
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* s->uncompressed_chunk may be too small to cover the large all-zeroes
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* section. dmg_read_chunk is called to find s->current_chunk */
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if (s->types[s->current_chunk] == 2) { /* all zeroes block entry */
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memset(buf + i * 512, 0, 512);
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qemu_iovec_memset(qiov, i * 512, 0, 512);
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continue;
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}
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sector_offset_in_chunk = sector_num + i - s->sectors[s->current_chunk];
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memcpy(buf + i * 512,
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s->uncompressed_chunk + sector_offset_in_chunk * 512, 512);
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data = s->uncompressed_chunk + sector_offset_in_chunk * 512;
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qemu_iovec_from_buf(qiov, i * 512, data, 512);
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}
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return 0;
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}
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static coroutine_fn int dmg_co_read(BlockDriverState *bs, int64_t sector_num,
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uint8_t *buf, int nb_sectors)
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{
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int ret;
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BDRVDMGState *s = bs->opaque;
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qemu_co_mutex_lock(&s->lock);
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ret = dmg_read(bs, sector_num, buf, nb_sectors);
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ret = 0;
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fail:
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qemu_co_mutex_unlock(&s->lock);
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return ret;
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}
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@ -715,7 +721,7 @@ static BlockDriver bdrv_dmg = {
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.instance_size = sizeof(BDRVDMGState),
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.bdrv_probe = dmg_probe,
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.bdrv_open = dmg_open,
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.bdrv_read = dmg_co_read,
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.bdrv_co_preadv = dmg_co_preadv,
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.bdrv_close = dmg_close,
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};
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