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Re: [Qemu-block] [PATCH v4 05/20] iscsi: Switch cluster_sectors to byte-
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-block] [PATCH v4 05/20] iscsi: Switch cluster_sectors to byte-based |
Date: |
Wed, 18 Oct 2017 11:20:35 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 |
On 12/10/2017 20:59, Eric Blake wrote:
> We are gradually converting to byte-based interfaces, as they are
> easier to reason about than sector-based. Convert all uses of
> the cluster size in sectors, along with adding assertions that we
> are not dividing by zero.
>
> Signed-off-by: Eric Blake <address@hidden>
>
> ---
> v2: no change
> ---
> block/iscsi.c | 56 +++++++++++++++++++++++++++++++++++---------------------
> 1 file changed, 35 insertions(+), 21 deletions(-)
>
> diff --git a/block/iscsi.c b/block/iscsi.c
> index 4683f3b244..8f903d8370 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -84,7 +84,7 @@ typedef struct IscsiLun {
> unsigned long *allocmap;
> unsigned long *allocmap_valid;
> long allocmap_size;
> - int cluster_sectors;
> + int cluster_size;
> bool use_16_for_rw;
> bool write_protected;
> bool lbpme;
> @@ -427,9 +427,10 @@ static int iscsi_allocmap_init(IscsiLun *iscsilun, int
> open_flags)
> {
> iscsi_allocmap_free(iscsilun);
>
> + assert(iscsilun->cluster_size);
> iscsilun->allocmap_size =
> - DIV_ROUND_UP(sector_lun2qemu(iscsilun->num_blocks, iscsilun),
> - iscsilun->cluster_sectors);
> + DIV_ROUND_UP(iscsilun->num_blocks * iscsilun->block_size,
> + iscsilun->cluster_size);
>
> iscsilun->allocmap = bitmap_try_new(iscsilun->allocmap_size);
> if (!iscsilun->allocmap) {
> @@ -437,7 +438,7 @@ static int iscsi_allocmap_init(IscsiLun *iscsilun, int
> open_flags)
> }
>
> if (open_flags & BDRV_O_NOCACHE) {
> - /* in case that cache.direct = on all allocmap entries are
> + /* when cache.direct = on all allocmap entries are
> * treated as invalid to force a relookup of the block
> * status on every read request */
> return 0;
> @@ -458,17 +459,19 @@ iscsi_allocmap_update(IscsiLun *iscsilun, int64_t
> sector_num,
> int nb_sectors, bool allocated, bool valid)
> {
> int64_t cl_num_expanded, nb_cls_expanded, cl_num_shrunk, nb_cls_shrunk;
> + int cluster_sectors = iscsilun->cluster_size >> BDRV_SECTOR_BITS;
>
> if (iscsilun->allocmap == NULL) {
> return;
> }
> /* expand to entirely contain all affected clusters */
> - cl_num_expanded = sector_num / iscsilun->cluster_sectors;
> + assert(cluster_sectors);
> + cl_num_expanded = sector_num / cluster_sectors;
> nb_cls_expanded = DIV_ROUND_UP(sector_num + nb_sectors,
> - iscsilun->cluster_sectors) -
> cl_num_expanded;
> + cluster_sectors) - cl_num_expanded;
> /* shrink to touch only completely contained clusters */
> - cl_num_shrunk = DIV_ROUND_UP(sector_num, iscsilun->cluster_sectors);
> - nb_cls_shrunk = (sector_num + nb_sectors) / iscsilun->cluster_sectors
> + cl_num_shrunk = DIV_ROUND_UP(sector_num, cluster_sectors);
> + nb_cls_shrunk = (sector_num + nb_sectors) / cluster_sectors
> - cl_num_shrunk;
> if (allocated) {
> bitmap_set(iscsilun->allocmap, cl_num_expanded, nb_cls_expanded);
> @@ -532,9 +535,12 @@ iscsi_allocmap_is_allocated(IscsiLun *iscsilun, int64_t
> sector_num,
> if (iscsilun->allocmap == NULL) {
> return true;
> }
> - size = DIV_ROUND_UP(sector_num + nb_sectors, iscsilun->cluster_sectors);
> + assert(iscsilun->cluster_size);
> + size = DIV_ROUND_UP(sector_num + nb_sectors,
> + iscsilun->cluster_size >> BDRV_SECTOR_BITS);
> return !(find_next_bit(iscsilun->allocmap, size,
> - sector_num / iscsilun->cluster_sectors) == size);
> + sector_num * BDRV_SECTOR_SIZE /
> + iscsilun->cluster_size) == size);
> }
>
> static inline bool iscsi_allocmap_is_valid(IscsiLun *iscsilun,
> @@ -544,9 +550,12 @@ static inline bool iscsi_allocmap_is_valid(IscsiLun
> *iscsilun,
> if (iscsilun->allocmap_valid == NULL) {
> return false;
> }
> - size = DIV_ROUND_UP(sector_num + nb_sectors, iscsilun->cluster_sectors);
> + assert(iscsilun->cluster_size);
> + size = DIV_ROUND_UP(sector_num + nb_sectors,
> + iscsilun->cluster_size >> BDRV_SECTOR_BITS);
> return (find_next_zero_bit(iscsilun->allocmap_valid, size,
> - sector_num / iscsilun->cluster_sectors) ==
> size);
> + sector_num * BDRV_SECTOR_SIZE /
> + iscsilun->cluster_size) == size);
> }
>
> static int coroutine_fn
> @@ -781,16 +790,21 @@ static int coroutine_fn iscsi_co_readv(BlockDriverState
> *bs,
> BlockDriverState *file;
> /* check the block status from the beginning of the cluster
> * containing the start sector */
> - int64_t ret = iscsi_co_get_block_status(bs,
> - sector_num - sector_num %
> iscsilun->cluster_sectors,
> - BDRV_REQUEST_MAX_SECTORS, &pnum, &file);
> + int cluster_sectors = iscsilun->cluster_size >> BDRV_SECTOR_BITS;
> + int head;
> + int64_t ret;
> +
> + assert(cluster_sectors);
> + head = sector_num % cluster_sectors;
> + ret = iscsi_co_get_block_status(bs, sector_num - head,
> + BDRV_REQUEST_MAX_SECTORS, &pnum,
> + &file);
> if (ret < 0) {
> return ret;
> }
> /* if the whole request falls into an unallocated area we can avoid
> - * to read and directly return zeroes instead */
> - if (ret & BDRV_BLOCK_ZERO &&
> - pnum >= nb_sectors + sector_num % iscsilun->cluster_sectors) {
> + * reading and directly return zeroes instead */
> + if (ret & BDRV_BLOCK_ZERO && pnum >= nb_sectors + head) {
> qemu_iovec_memset(iov, 0, 0x00, iov->size);
> return 0;
> }
> @@ -1930,8 +1944,8 @@ static int iscsi_open(BlockDriverState *bs, QDict
> *options, int flags,
> * reasonable size */
> if (iscsilun->bl.opt_unmap_gran * iscsilun->block_size >= 4 * 1024 &&
> iscsilun->bl.opt_unmap_gran * iscsilun->block_size <= 16 * 1024 *
> 1024) {
> - iscsilun->cluster_sectors = (iscsilun->bl.opt_unmap_gran *
> - iscsilun->block_size) >>
> BDRV_SECTOR_BITS;
> + iscsilun->cluster_size = iscsilun->bl.opt_unmap_gran *
> + iscsilun->block_size;
> if (iscsilun->lbprz) {
> ret = iscsi_allocmap_init(iscsilun, bs->open_flags);
> }
> @@ -2137,7 +2151,7 @@ static int iscsi_get_info(BlockDriverState *bs,
> BlockDriverInfo *bdi)
> IscsiLun *iscsilun = bs->opaque;
> bdi->unallocated_blocks_are_zero = iscsilun->lbprz;
> bdi->can_write_zeroes_with_unmap = iscsilun->lbprz &&
> iscsilun->lbp.lbpws;
> - bdi->cluster_size = iscsilun->cluster_sectors * BDRV_SECTOR_SIZE;
> + bdi->cluster_size = iscsilun->cluster_size;
> return 0;
> }
>
Acked-by: Paolo Bonzini <address@hidden>
- [Qemu-block] [PATCH v4 00/20] add byte-based block_status driver callbacks, Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 01/20] block: Add .bdrv_co_block_status() callback, Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 02/20] block: Switch passthrough drivers to .bdrv_co_block_status(), Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 03/20] file-posix: Switch to .bdrv_co_block_status(), Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 04/20] gluster: Switch to .bdrv_co_block_status(), Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 05/20] iscsi: Switch cluster_sectors to byte-based, Eric Blake, 2017/10/12
- Re: [Qemu-block] [PATCH v4 05/20] iscsi: Switch cluster_sectors to byte-based,
Paolo Bonzini <=
- [Qemu-block] [PATCH v4 06/20] iscsi: Switch iscsi_allocmap_update() to byte-based, Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 07/20] iscsi: Switch to .bdrv_co_block_status(), Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 08/20] null: Switch to .bdrv_co_block_status(), Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 09/20] parallels: Switch to .bdrv_co_block_status(), Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 10/20] qcow: Switch to .bdrv_co_block_status(), Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 11/20] qcow2: Switch to .bdrv_co_block_status(), Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 12/20] qed: Switch to .bdrv_co_block_status(), Eric Blake, 2017/10/12
- [Qemu-block] [PATCH v4 13/20] raw: Switch to .bdrv_co_block_status(), Eric Blake, 2017/10/12