Am 01.12.2010 16:35, schrieb Christoph Hellwig:
> 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 16:17:32.922003704 +0100
> +++ qemu/block.c 2010-11-29 14:10:21.793255565 +0100
> @@ -1499,6 +1499,15 @@ int bdrv_has_zero_init(BlockDriverState
> return 1;
> }
>
> +int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors)
> +{
> + if (!bs->drv)
> + return -ENOMEDIUM;
> + if (!bs->drv->bdrv_discard)
> + return 0;
Missing braces.
> + 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 16:17:32.929004193 +0100
> +++ qemu/block.h 2010-11-29 14:07:00.267003145 +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 16:17:32.935003774 +0100
> +++ qemu/block_int.h 2010-11-29 14:09:31.926264704 +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)
Is there no way to get this value automatically?
At least for non-raw images (and it should be trivial to implement this
in qcow2) I guess we'll want to set it to the cluster size of the image
instead of requiring the user to set this value.
Kevin
