On Thu, 25 Nov 2010, Christoph Hellwig wrote:
> Add a new bdrv_discard method to free blocks in a mapping image, and a new
> drive property to set the granularity for these discard. If no discard
> granularity support is set discard support is disabled.
>
> Signed-off-by: Christoph Hellwig <h...@lst.de>
>
> Index: qemu/block.c
> ===================================================================
> --- qemu.orig/block.c 2010-11-25 12:34:10.580256183 +0100
> +++ qemu/block.c 2010-11-25 12:34:41.761254654 +0100
> @@ -1499,6 +1499,13 @@ int bdrv_has_zero_init(BlockDriverState
> return 1;
> }
>
> +int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors)
> +{
> + if (!bs->drv || !bs->drv->bdrv_discard)
> + return 0;
> + return bs->drv->bdrv_discard(bs, sector_num, nb_sectors);
> +}
> +
> /*
> * Returns true iff the specified sector is present in the disk image.
> Drivers
> * not implementing the functionality are assumed to not support backing
> files,
> Index: qemu/block.h
> ===================================================================
> --- qemu.orig/block.h 2010-11-25 12:34:10.589253738 +0100
> +++ qemu/block.h 2010-11-25 12:34:12.148012156 +0100
> @@ -146,6 +146,7 @@ int bdrv_flush(BlockDriverState *bs);
> void bdrv_flush_all(void);
> void bdrv_close_all(void);
>
> +int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
> int bdrv_has_zero_init(BlockDriverState *bs);
> int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int
> nb_sectors,
> int *pnum);
> Index: qemu/block_int.h
> ===================================================================
> --- qemu.orig/block_int.h 2010-11-25 12:34:10.595254018 +0100
> +++ qemu/block_int.h 2010-11-25 12:34:12.150013832 +0100
> @@ -73,6 +73,8 @@ struct BlockDriver {
> BlockDriverCompletionFunc *cb, void *opaque);
> BlockDriverAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs,
> BlockDriverCompletionFunc *cb, void *opaque);
> + int (*bdrv_discard)(BlockDriverState *bs, int64_t sector_num,
> + int nb_sectors);
>
> int (*bdrv_aio_multiwrite)(BlockDriverState *bs, BlockRequest *reqs,
> int num_reqs);
> @@ -227,6 +229,7 @@ typedef struct BlockConf {
> uint16_t logical_block_size;
> uint16_t min_io_size;
> uint32_t opt_io_size;
> + uint32_t discard_granularity;
> } BlockConf;
>
> static inline unsigned int get_physical_block_exp(BlockConf *conf)
> @@ -249,6 +252,8 @@ static inline unsigned int get_physical_
> DEFINE_PROP_UINT16("physical_block_size", _state, \
> _conf.physical_block_size, 512), \
> DEFINE_PROP_UINT16("min_io_size", _state, _conf.min_io_size, 0), \
> - DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0)
> + DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0), \
> + DEFINE_PROP_UINT32("discard_granularity", _state, \
> + _conf.discard_granularity, 0)
Tab here.
>
> #endif /* BLOCK_INT_H */
> Index: qemu/block/raw.c
> ===================================================================
> --- qemu.orig/block/raw.c 2010-11-25 12:34:10.601259605 +0100
> +++ qemu/block/raw.c 2010-11-25 12:34:12.155004124 +0100
> @@ -65,6 +65,11 @@ static int raw_probe(const uint8_t *buf,
> return 1; /* everything can be opened as raw image */
> }
>
> +static int raw_discard(BlockDriverState *bs, int64_t sector_num, int
> nb_sectors)
> +{
> + return bdrv_discard(bs->file, sector_num, nb_sectors);
> +}
> +
> static int raw_is_inserted(BlockDriverState *bs)
> {
> return bdrv_is_inserted(bs->file);
> @@ -130,6 +135,7 @@ static BlockDriver bdrv_raw = {
> .bdrv_aio_readv = raw_aio_readv,
> .bdrv_aio_writev = raw_aio_writev,
> .bdrv_aio_flush = raw_aio_flush,
> + .bdrv_discard = raw_discard,
>
> .bdrv_is_inserted = raw_is_inserted,
> .bdrv_eject = raw_eject,
>
--
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