| Message ID | 1463493552-12094-1-git-send-email-pl@kamp.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 05/17 15:59, Peter Lieven wrote: > until now the allocation map was used only as a hint if a cluster > is allocated or not. If a block was not allocated (or Qemu had > no info about the allocation status) a get_block_status call was > issued to check the allocation status and possibly avoid > a subsequent read of unallocated sectors. If a block known to be > allocated the get_block_status call was omitted. In the other case > a get_block_status call was issued before every read to avoid > the necessity for a consistent allocation map. To avoid the > potential overhead of calling get_block_status for each and > every read request this took only place for the bigger requests. > > This patch enhances this mechanism to cache the allocation > status and avoid calling get_block_status for blocks where > the allocation status has been queried before. This allows > for bypassing the read request even for smaller requests and > additionally omits calling get_block_status for known to be > unallocated blocks. Looks good overall, I have some minor comments below, though. > > Signed-off-by: Peter Lieven <pl@kamp.de> > --- > block/iscsi.c | 194 +++++++++++++++++++++++++++++++++++++++++++--------------- > 1 file changed, 144 insertions(+), 50 deletions(-) > > diff --git a/block/iscsi.c b/block/iscsi.c > index 10f3906..b25bebd 100644 > --- a/block/iscsi.c > +++ b/block/iscsi.c > @@ -2,7 +2,7 @@ > * QEMU Block driver for iSCSI images > * > * Copyright (c) 2010-2011 Ronnie Sahlberg <ronniesahlberg@gmail.com> > - * Copyright (c) 2012-2015 Peter Lieven <pl@kamp.de> > + * Copyright (c) 2012-2016 Peter Lieven <pl@kamp.de> > * > * Permission is hereby granted, free of charge, to any person obtaining a copy > * of this software and associated documentation files (the "Software"), to deal > @@ -62,7 +62,9 @@ typedef struct IscsiLun { > struct scsi_inquiry_logical_block_provisioning lbp; > struct scsi_inquiry_block_limits bl; > unsigned char *zeroblock; > - unsigned long *allocationmap; > + unsigned long *allocmap; > + unsigned long *allocmap_valid; > + long allocmap_size; Could you add some comments about the relation between these three fields and their respective semantics? > int cluster_sectors; > bool use_16_for_rw; > bool write_protected; > @@ -415,39 +417,127 @@ static bool is_request_lun_aligned(int64_t sector_num, int nb_sectors, > return 1; > } > > -static unsigned long *iscsi_allocationmap_init(IscsiLun *iscsilun) > +static void iscsi_allocmap_free(IscsiLun *iscsilun) > { > - return bitmap_try_new(DIV_ROUND_UP(sector_lun2qemu(iscsilun->num_blocks, > - iscsilun), > - iscsilun->cluster_sectors)); > + g_free(iscsilun->allocmap); > + g_free(iscsilun->allocmap_valid); > + iscsilun->allocmap = NULL; > + iscsilun->allocmap_valid = NULL; > } > > -static void iscsi_allocationmap_set(IscsiLun *iscsilun, int64_t sector_num, > - int nb_sectors) > + > +static int iscsi_allocmap_init(IscsiLun *iscsilun, int open_flags) > { > - if (iscsilun->allocationmap == NULL) { > - return; > + iscsilun->allocmap_size = > + DIV_ROUND_UP(sector_lun2qemu(iscsilun->num_blocks, iscsilun), > + iscsilun->cluster_sectors); > + > + iscsilun->allocmap = bitmap_try_new(iscsilun->allocmap_size); > + if (!iscsilun->allocmap) { > + return -ENOMEM; > + } > + > + if (open_flags & BDRV_O_NOCACHE) { > + return 0; > + } > + > + iscsilun->allocmap_valid = bitmap_try_new(iscsilun->allocmap_size); > + if (!iscsilun->allocmap_valid) { Do you want to free iscsilun->allocmap? If you keep the two maps together... > + return -ENOMEM; > } > - bitmap_set(iscsilun->allocationmap, > - sector_num / iscsilun->cluster_sectors, > - DIV_ROUND_UP(nb_sectors, iscsilun->cluster_sectors)); > + > + return 0; > } > > -static void iscsi_allocationmap_clear(IscsiLun *iscsilun, int64_t sector_num, > - int nb_sectors) > +static void > +iscsi_allocmap_update(IscsiLun *iscsilun, int64_t sector_num, > + int nb_sectors, bool allocated, bool valid) ^ Looks like the parameter list is not aligned. > { > int64_t cluster_num, nb_clusters; > - if (iscsilun->allocationmap == NULL) { > + > + if (iscsilun->allocmap == NULL) { > return; > } > cluster_num = DIV_ROUND_UP(sector_num, iscsilun->cluster_sectors); > nb_clusters = (sector_num + nb_sectors) / iscsilun->cluster_sectors > - cluster_num; > - if (nb_clusters > 0) { > - bitmap_clear(iscsilun->allocationmap, cluster_num, nb_clusters); > + if (allocated) { > + bitmap_set(iscsilun->allocmap, > + sector_num / iscsilun->cluster_sectors, > + DIV_ROUND_UP(nb_sectors, iscsilun->cluster_sectors)); > + } else if (nb_clusters > 0) { > + bitmap_clear(iscsilun->allocmap, cluster_num, nb_clusters); > + } > + > + if (iscsilun->allocmap_valid == NULL) { > + return; > + } ... there will be one less branch and code is simpler. > + if (valid) { > + if (nb_clusters > 0) { > + bitmap_set(iscsilun->allocmap_valid, cluster_num, nb_clusters); > + } > + } else { > + bitmap_clear(iscsilun->allocmap_valid, > + sector_num / iscsilun->cluster_sectors, > + DIV_ROUND_UP(nb_sectors, iscsilun->cluster_sectors)); > } > } > > +static void > +iscsi_allocmap_set_allocated(IscsiLun *iscsilun, int64_t sector_num, > + int nb_sectors) > +{ > + iscsi_allocmap_update(iscsilun, sector_num, nb_sectors, true, true); > +} > + > +static void > +iscsi_allocmap_set_unallocated(IscsiLun *iscsilun, int64_t sector_num, > + int nb_sectors) > +{ > + iscsi_allocmap_update(iscsilun, sector_num, nb_sectors, false, true); > +} > + > +static void iscsi_allocmap_set_invalid(IscsiLun *iscsilun, int64_t sector_num, > + int nb_sectors) > +{ > + iscsi_allocmap_update(iscsilun, sector_num, nb_sectors, false, false); > +} > + > +static void iscsi_allocmap_invalidate(IscsiLun *iscsilun) > +{ > + if (iscsilun->allocmap) { > + bitmap_zero(iscsilun->allocmap, iscsilun->allocmap_size); > + } > + if (iscsilun->allocmap_valid) { > + bitmap_zero(iscsilun->allocmap_valid, iscsilun->allocmap_size); > + } > +} > + > +static inline bool > +iscsi_allocmap_is_allocated(IscsiLun *iscsilun, int64_t sector_num, > + int nb_sectors) > +{ > + unsigned long size; > + if (iscsilun->allocmap == NULL) { > + return true; > + } > + size = DIV_ROUND_UP(sector_num + nb_sectors, iscsilun->cluster_sectors); > + return !(find_next_bit(iscsilun->allocmap, size, > + sector_num / iscsilun->cluster_sectors) == size); > +} > + > +static inline bool iscsi_allocmap_is_valid(IscsiLun *iscsilun, > + int64_t sector_num, int nb_sectors) > +{ > + unsigned long size; > + if (iscsilun->allocmap_valid == NULL) { > + return false; > + } > + size = DIV_ROUND_UP(sector_num + nb_sectors, iscsilun->cluster_sectors); > + return (find_next_zero_bit(iscsilun->allocmap_valid, size, > + sector_num / iscsilun->cluster_sectors) == size); > +} > + > static int coroutine_fn > iscsi_co_writev_flags(BlockDriverState *bs, int64_t sector_num, int nb_sectors, > QEMUIOVector *iov, int flags) > @@ -507,26 +597,16 @@ retry: > } > > if (iTask.status != SCSI_STATUS_GOOD) { > + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); > return iTask.err_code; > } > > - iscsi_allocationmap_set(iscsilun, sector_num, nb_sectors); > + iscsi_allocmap_set_allocated(iscsilun, sector_num, nb_sectors); > > return 0; > } > > > -static bool iscsi_allocationmap_is_allocated(IscsiLun *iscsilun, > - int64_t sector_num, int nb_sectors) > -{ > - unsigned long size; > - if (iscsilun->allocationmap == NULL) { > - return true; > - } > - size = DIV_ROUND_UP(sector_num + nb_sectors, iscsilun->cluster_sectors); > - return !(find_next_bit(iscsilun->allocationmap, size, > - sector_num / iscsilun->cluster_sectors) == size); > -} > > static int64_t coroutine_fn iscsi_co_get_block_status(BlockDriverState *bs, > int64_t sector_num, > @@ -611,9 +691,9 @@ retry: > } > > if (ret & BDRV_BLOCK_ZERO) { > - iscsi_allocationmap_clear(iscsilun, sector_num, *pnum); > + iscsi_allocmap_set_unallocated(iscsilun, sector_num, *pnum); > } else { > - iscsi_allocationmap_set(iscsilun, sector_num, *pnum); > + iscsi_allocmap_set_allocated(iscsilun, sector_num, *pnum); > } > > if (*pnum > nb_sectors) { > @@ -629,7 +709,7 @@ out: > return ret; > } > > -static int coroutine_fn iscsi_co_readv(BlockDriverState *bs, > + static int coroutine_fn iscsi_co_readv(BlockDriverState *bs, A superfluous leading whitespace? > int64_t sector_num, int nb_sectors, > QEMUIOVector *iov) > { > @@ -648,16 +728,25 @@ static int coroutine_fn iscsi_co_readv(BlockDriverState *bs, > return -EINVAL; > } > > - if (iscsilun->lbprz && nb_sectors >= ISCSI_CHECKALLOC_THRES && > - !iscsi_allocationmap_is_allocated(iscsilun, sector_num, nb_sectors)) { > - int64_t ret; > + if (iscsi_allocmap_is_valid(iscsilun, sector_num, nb_sectors) && > + !iscsi_allocmap_is_allocated(iscsilun, sector_num, nb_sectors)) { > + qemu_iovec_memset(iov, 0, 0x00, iov->size); > + return 0; > + } > + > + if (nb_sectors >= ISCSI_CHECKALLOC_THRES && > + !iscsi_allocmap_is_valid(iscsilun, sector_num, nb_sectors) && > + !iscsi_allocmap_is_allocated(iscsilun, sector_num, nb_sectors)) { > int pnum; > BlockDriverState *file; > - ret = iscsi_co_get_block_status(bs, sector_num, INT_MAX, &pnum, &file); > + int64_t ret = iscsi_co_get_block_status(bs, > + sector_num - sector_num % iscsilun->cluster_sectors, > + INT_MAX, &pnum, &file); > if (ret < 0) { > return ret; > } > - if (ret & BDRV_BLOCK_ZERO && pnum >= nb_sectors) { > + if (ret & BDRV_BLOCK_ZERO && > + pnum >= nb_sectors + sector_num % iscsilun->cluster_sectors) { > qemu_iovec_memset(iov, 0, 0x00, iov->size); > return 0; > } > @@ -892,7 +981,6 @@ static BlockAIOCB *iscsi_aio_ioctl(BlockDriverState *bs, > } > > iscsi_set_events(iscsilun); > - Superfluous whitespace change. > return &acb->common; > } > > @@ -963,7 +1051,7 @@ retry: > return iTask.err_code; > } > > - iscsi_allocationmap_clear(iscsilun, sector_num, nb_sectors); > + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); > > return 0; > } > @@ -1053,13 +1141,14 @@ retry: > } > > if (iTask.status != SCSI_STATUS_GOOD) { > + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); > return iTask.err_code; > } > > if (flags & BDRV_REQ_MAY_UNMAP) { > - iscsi_allocationmap_clear(iscsilun, sector_num, nb_sectors); > + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); > } else { > - iscsi_allocationmap_set(iscsilun, sector_num, nb_sectors); > + iscsi_allocmap_set_allocated(iscsilun, sector_num, nb_sectors); > } > > return 0; > @@ -1633,10 +1722,7 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags, > iscsilun->cluster_sectors = (iscsilun->bl.opt_unmap_gran * > iscsilun->block_size) >> BDRV_SECTOR_BITS; > if (iscsilun->lbprz) { > - iscsilun->allocationmap = iscsi_allocationmap_init(iscsilun); > - if (iscsilun->allocationmap == NULL) { > - ret = -ENOMEM; > - } > + ret = iscsi_allocmap_init(iscsilun, bs->open_flags); > } > } > > @@ -1673,7 +1759,7 @@ static void iscsi_close(BlockDriverState *bs) > } > iscsi_destroy_context(iscsi); > g_free(iscsilun->zeroblock); > - g_free(iscsilun->allocationmap); > + iscsi_allocmap_free(iscsilun); > memset(iscsilun, 0, sizeof(IscsiLun)); > } > > @@ -1750,9 +1836,9 @@ static int iscsi_truncate(BlockDriverState *bs, int64_t offset) > return -EINVAL; > } > > - if (iscsilun->allocationmap != NULL) { > - g_free(iscsilun->allocationmap); > - iscsilun->allocationmap = iscsi_allocationmap_init(iscsilun); > + if (iscsilun->allocmap != NULL) { > + iscsi_allocmap_free(iscsilun); > + iscsi_allocmap_init(iscsilun, bs->open_flags); Need to handle the return value here? > } > > return 0; Thanks, Fam
Am 18.05.2016 um 09:41 schrieb Fam Zheng: > On Tue, 05/17 15:59, Peter Lieven wrote: >> until now the allocation map was used only as a hint if a cluster >> is allocated or not. If a block was not allocated (or Qemu had >> no info about the allocation status) a get_block_status call was >> issued to check the allocation status and possibly avoid >> a subsequent read of unallocated sectors. If a block known to be >> allocated the get_block_status call was omitted. In the other case >> a get_block_status call was issued before every read to avoid >> the necessity for a consistent allocation map. To avoid the >> potential overhead of calling get_block_status for each and >> every read request this took only place for the bigger requests. >> >> This patch enhances this mechanism to cache the allocation >> status and avoid calling get_block_status for blocks where >> the allocation status has been queried before. This allows >> for bypassing the read request even for smaller requests and >> additionally omits calling get_block_status for known to be >> unallocated blocks. > Looks good overall, I have some minor comments below, though. > >> Signed-off-by: Peter Lieven <pl@kamp.de> >> --- >> block/iscsi.c | 194 +++++++++++++++++++++++++++++++++++++++++++--------------- >> 1 file changed, 144 insertions(+), 50 deletions(-) >> >> diff --git a/block/iscsi.c b/block/iscsi.c >> index 10f3906..b25bebd 100644 >> --- a/block/iscsi.c >> +++ b/block/iscsi.c >> @@ -2,7 +2,7 @@ >> * QEMU Block driver for iSCSI images >> * >> * Copyright (c) 2010-2011 Ronnie Sahlberg <ronniesahlberg@gmail.com> >> - * Copyright (c) 2012-2015 Peter Lieven <pl@kamp.de> >> + * Copyright (c) 2012-2016 Peter Lieven <pl@kamp.de> >> * >> * Permission is hereby granted, free of charge, to any person obtaining a copy >> * of this software and associated documentation files (the "Software"), to deal >> @@ -62,7 +62,9 @@ typedef struct IscsiLun { >> struct scsi_inquiry_logical_block_provisioning lbp; >> struct scsi_inquiry_block_limits bl; >> unsigned char *zeroblock; >> - unsigned long *allocationmap; >> + unsigned long *allocmap; >> + unsigned long *allocmap_valid; >> + long allocmap_size; > Could you add some comments about the relation between these three fields and > their respective semantics? Sure. Are you happy with this comment? */ The allocation map tracks which clusters (pages) on the iSCSI target are * allocated and which are not. In case a target returns zeros for unallocated * pages (iscsilun->lprz) we can directly return zeros instead of reading zeros over * the wire if a read request falls within an unallocated block. As there are 3 possible * states we need 2 bitmaps to track. allocmap_valid keeps track if Qemus * information about a page is valid. allocmap tracks if a page is allocated or * not. In case Qemus has no valid information about a page the corresponding * allocmap entry should be switched to unallocated as well to force a new lookup of * the allocation status as lookups are generally skipped if a page is suspect * to be allocated. If a iSCSI target is opened with cache.direct = on the allocmap_valid * does not exist turning all cached information invalid so that a fresh lookup * is made for any page even if allocmap entry returns its unallocated. */ > >> int cluster_sectors; >> bool use_16_for_rw; >> bool write_protected; >> @@ -415,39 +417,127 @@ static bool is_request_lun_aligned(int64_t sector_num, int nb_sectors, >> return 1; >> } >> >> -static unsigned long *iscsi_allocationmap_init(IscsiLun *iscsilun) >> +static void iscsi_allocmap_free(IscsiLun *iscsilun) >> { >> - return bitmap_try_new(DIV_ROUND_UP(sector_lun2qemu(iscsilun->num_blocks, >> - iscsilun), >> - iscsilun->cluster_sectors)); >> + g_free(iscsilun->allocmap); >> + g_free(iscsilun->allocmap_valid); >> + iscsilun->allocmap = NULL; >> + iscsilun->allocmap_valid = NULL; >> } >> >> -static void iscsi_allocationmap_set(IscsiLun *iscsilun, int64_t sector_num, >> - int nb_sectors) >> + >> +static int iscsi_allocmap_init(IscsiLun *iscsilun, int open_flags) >> { >> - if (iscsilun->allocationmap == NULL) { >> - return; >> + iscsilun->allocmap_size = >> + DIV_ROUND_UP(sector_lun2qemu(iscsilun->num_blocks, iscsilun), >> + iscsilun->cluster_sectors); >> + >> + iscsilun->allocmap = bitmap_try_new(iscsilun->allocmap_size); >> + if (!iscsilun->allocmap) { >> + return -ENOMEM; >> + } >> + >> + if (open_flags & BDRV_O_NOCACHE) { >> + return 0; >> + } >> + >> + iscsilun->allocmap_valid = bitmap_try_new(iscsilun->allocmap_size); >> + if (!iscsilun->allocmap_valid) { > Do you want to free iscsilun->allocmap? If you keep the two maps together... It does still work without the allocmap_valid, but it might be a good idea to free that memory if we are under memory pressure. > >> + return -ENOMEM; >> } >> - bitmap_set(iscsilun->allocationmap, >> - sector_num / iscsilun->cluster_sectors, >> - DIV_ROUND_UP(nb_sectors, iscsilun->cluster_sectors)); >> + >> + return 0; >> } >> >> -static void iscsi_allocationmap_clear(IscsiLun *iscsilun, int64_t sector_num, >> - int nb_sectors) >> +static void >> +iscsi_allocmap_update(IscsiLun *iscsilun, int64_t sector_num, >> + int nb_sectors, bool allocated, bool valid) > ^ > Looks like the parameter list is not aligned. > >> { >> int64_t cluster_num, nb_clusters; >> - if (iscsilun->allocationmap == NULL) { >> + >> + if (iscsilun->allocmap == NULL) { >> return; >> } >> cluster_num = DIV_ROUND_UP(sector_num, iscsilun->cluster_sectors); >> nb_clusters = (sector_num + nb_sectors) / iscsilun->cluster_sectors >> - cluster_num; >> - if (nb_clusters > 0) { >> - bitmap_clear(iscsilun->allocationmap, cluster_num, nb_clusters); >> + if (allocated) { >> + bitmap_set(iscsilun->allocmap, >> + sector_num / iscsilun->cluster_sectors, >> + DIV_ROUND_UP(nb_sectors, iscsilun->cluster_sectors)); >> + } else if (nb_clusters > 0) { >> + bitmap_clear(iscsilun->allocmap, cluster_num, nb_clusters); >> + } >> + >> + if (iscsilun->allocmap_valid == NULL) { >> + return; >> + } > ... there will be one less branch and code is simpler. I have to keep this one. Its valid to have no allocmap_valid bitmap. Thats the case when cache.direct is on. In this case the map is always invalid which returns to the old allocmap behaviour. > >> + if (valid) { >> + if (nb_clusters > 0) { >> + bitmap_set(iscsilun->allocmap_valid, cluster_num, nb_clusters); >> + } >> + } else { >> + bitmap_clear(iscsilun->allocmap_valid, >> + sector_num / iscsilun->cluster_sectors, >> + DIV_ROUND_UP(nb_sectors, iscsilun->cluster_sectors)); >> } >> } >> >> +static void >> +iscsi_allocmap_set_allocated(IscsiLun *iscsilun, int64_t sector_num, >> + int nb_sectors) >> +{ >> + iscsi_allocmap_update(iscsilun, sector_num, nb_sectors, true, true); >> +} >> + >> +static void >> +iscsi_allocmap_set_unallocated(IscsiLun *iscsilun, int64_t sector_num, >> + int nb_sectors) >> +{ >> + iscsi_allocmap_update(iscsilun, sector_num, nb_sectors, false, true); >> +} >> + >> +static void iscsi_allocmap_set_invalid(IscsiLun *iscsilun, int64_t sector_num, >> + int nb_sectors) >> +{ >> + iscsi_allocmap_update(iscsilun, sector_num, nb_sectors, false, false); >> +} >> + >> +static void iscsi_allocmap_invalidate(IscsiLun *iscsilun) >> +{ >> + if (iscsilun->allocmap) { >> + bitmap_zero(iscsilun->allocmap, iscsilun->allocmap_size); >> + } >> + if (iscsilun->allocmap_valid) { >> + bitmap_zero(iscsilun->allocmap_valid, iscsilun->allocmap_size); >> + } >> +} >> + >> +static inline bool >> +iscsi_allocmap_is_allocated(IscsiLun *iscsilun, int64_t sector_num, >> + int nb_sectors) >> +{ >> + unsigned long size; >> + if (iscsilun->allocmap == NULL) { >> + return true; >> + } >> + size = DIV_ROUND_UP(sector_num + nb_sectors, iscsilun->cluster_sectors); >> + return !(find_next_bit(iscsilun->allocmap, size, >> + sector_num / iscsilun->cluster_sectors) == size); >> +} >> + >> +static inline bool iscsi_allocmap_is_valid(IscsiLun *iscsilun, >> + int64_t sector_num, int nb_sectors) >> +{ >> + unsigned long size; >> + if (iscsilun->allocmap_valid == NULL) { >> + return false; >> + } >> + size = DIV_ROUND_UP(sector_num + nb_sectors, iscsilun->cluster_sectors); >> + return (find_next_zero_bit(iscsilun->allocmap_valid, size, >> + sector_num / iscsilun->cluster_sectors) == size); >> +} >> + >> static int coroutine_fn >> iscsi_co_writev_flags(BlockDriverState *bs, int64_t sector_num, int nb_sectors, >> QEMUIOVector *iov, int flags) >> @@ -507,26 +597,16 @@ retry: >> } >> >> if (iTask.status != SCSI_STATUS_GOOD) { >> + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); >> return iTask.err_code; >> } >> >> - iscsi_allocationmap_set(iscsilun, sector_num, nb_sectors); >> + iscsi_allocmap_set_allocated(iscsilun, sector_num, nb_sectors); >> >> return 0; >> } >> >> >> -static bool iscsi_allocationmap_is_allocated(IscsiLun *iscsilun, >> - int64_t sector_num, int nb_sectors) >> -{ >> - unsigned long size; >> - if (iscsilun->allocationmap == NULL) { >> - return true; >> - } >> - size = DIV_ROUND_UP(sector_num + nb_sectors, iscsilun->cluster_sectors); >> - return !(find_next_bit(iscsilun->allocationmap, size, >> - sector_num / iscsilun->cluster_sectors) == size); >> -} >> >> static int64_t coroutine_fn iscsi_co_get_block_status(BlockDriverState *bs, >> int64_t sector_num, >> @@ -611,9 +691,9 @@ retry: >> } >> >> if (ret & BDRV_BLOCK_ZERO) { >> - iscsi_allocationmap_clear(iscsilun, sector_num, *pnum); >> + iscsi_allocmap_set_unallocated(iscsilun, sector_num, *pnum); >> } else { >> - iscsi_allocationmap_set(iscsilun, sector_num, *pnum); >> + iscsi_allocmap_set_allocated(iscsilun, sector_num, *pnum); >> } >> >> if (*pnum > nb_sectors) { >> @@ -629,7 +709,7 @@ out: >> return ret; >> } >> >> -static int coroutine_fn iscsi_co_readv(BlockDriverState *bs, >> + static int coroutine_fn iscsi_co_readv(BlockDriverState *bs, > A superfluous leading whitespace? > >> int64_t sector_num, int nb_sectors, >> QEMUIOVector *iov) >> { >> @@ -648,16 +728,25 @@ static int coroutine_fn iscsi_co_readv(BlockDriverState *bs, >> return -EINVAL; >> } >> >> - if (iscsilun->lbprz && nb_sectors >= ISCSI_CHECKALLOC_THRES && >> - !iscsi_allocationmap_is_allocated(iscsilun, sector_num, nb_sectors)) { >> - int64_t ret; >> + if (iscsi_allocmap_is_valid(iscsilun, sector_num, nb_sectors) && >> + !iscsi_allocmap_is_allocated(iscsilun, sector_num, nb_sectors)) { >> + qemu_iovec_memset(iov, 0, 0x00, iov->size); >> + return 0; >> + } >> + >> + if (nb_sectors >= ISCSI_CHECKALLOC_THRES && >> + !iscsi_allocmap_is_valid(iscsilun, sector_num, nb_sectors) && >> + !iscsi_allocmap_is_allocated(iscsilun, sector_num, nb_sectors)) { >> int pnum; >> BlockDriverState *file; >> - ret = iscsi_co_get_block_status(bs, sector_num, INT_MAX, &pnum, &file); >> + int64_t ret = iscsi_co_get_block_status(bs, >> + sector_num - sector_num % iscsilun->cluster_sectors, >> + INT_MAX, &pnum, &file); >> if (ret < 0) { >> return ret; >> } >> - if (ret & BDRV_BLOCK_ZERO && pnum >= nb_sectors) { >> + if (ret & BDRV_BLOCK_ZERO && >> + pnum >= nb_sectors + sector_num % iscsilun->cluster_sectors) { >> qemu_iovec_memset(iov, 0, 0x00, iov->size); >> return 0; >> } >> @@ -892,7 +981,6 @@ static BlockAIOCB *iscsi_aio_ioctl(BlockDriverState *bs, >> } >> >> iscsi_set_events(iscsilun); >> - > Superfluous whitespace change. > >> return &acb->common; >> } >> >> @@ -963,7 +1051,7 @@ retry: >> return iTask.err_code; >> } >> >> - iscsi_allocationmap_clear(iscsilun, sector_num, nb_sectors); >> + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); >> >> return 0; >> } >> @@ -1053,13 +1141,14 @@ retry: >> } >> >> if (iTask.status != SCSI_STATUS_GOOD) { >> + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); >> return iTask.err_code; >> } >> >> if (flags & BDRV_REQ_MAY_UNMAP) { >> - iscsi_allocationmap_clear(iscsilun, sector_num, nb_sectors); >> + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); >> } else { >> - iscsi_allocationmap_set(iscsilun, sector_num, nb_sectors); >> + iscsi_allocmap_set_allocated(iscsilun, sector_num, nb_sectors); >> } >> >> return 0; >> @@ -1633,10 +1722,7 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags, >> iscsilun->cluster_sectors = (iscsilun->bl.opt_unmap_gran * >> iscsilun->block_size) >> BDRV_SECTOR_BITS; >> if (iscsilun->lbprz) { >> - iscsilun->allocationmap = iscsi_allocationmap_init(iscsilun); >> - if (iscsilun->allocationmap == NULL) { >> - ret = -ENOMEM; >> - } >> + ret = iscsi_allocmap_init(iscsilun, bs->open_flags); >> } >> } >> >> @@ -1673,7 +1759,7 @@ static void iscsi_close(BlockDriverState *bs) >> } >> iscsi_destroy_context(iscsi); >> g_free(iscsilun->zeroblock); >> - g_free(iscsilun->allocationmap); >> + iscsi_allocmap_free(iscsilun); >> memset(iscsilun, 0, sizeof(IscsiLun)); >> } >> >> @@ -1750,9 +1836,9 @@ static int iscsi_truncate(BlockDriverState *bs, int64_t offset) >> return -EINVAL; >> } >> >> - if (iscsilun->allocationmap != NULL) { >> - g_free(iscsilun->allocationmap); >> - iscsilun->allocationmap = iscsi_allocationmap_init(iscsilun); >> + if (iscsilun->allocmap != NULL) { >> + iscsi_allocmap_free(iscsilun); >> + iscsi_allocmap_init(iscsilun, bs->open_flags); > Need to handle the return value here? I think when originally implementing this we decide that a truncate should not fail if the allocmap can't be resized. The feature is just disabled in this case. Thinking about Jeffs comment on my NFS patch I also need to free allocmap_valid if we change from cache.direct = off -> on. Thanks for reviewing, Peter
diff --git a/block/iscsi.c b/block/iscsi.c index 10f3906..b25bebd 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -2,7 +2,7 @@ * QEMU Block driver for iSCSI images * * Copyright (c) 2010-2011 Ronnie Sahlberg <ronniesahlberg@gmail.com> - * Copyright (c) 2012-2015 Peter Lieven <pl@kamp.de> + * Copyright (c) 2012-2016 Peter Lieven <pl@kamp.de> * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal @@ -62,7 +62,9 @@ typedef struct IscsiLun { struct scsi_inquiry_logical_block_provisioning lbp; struct scsi_inquiry_block_limits bl; unsigned char *zeroblock; - unsigned long *allocationmap; + unsigned long *allocmap; + unsigned long *allocmap_valid; + long allocmap_size; int cluster_sectors; bool use_16_for_rw; bool write_protected; @@ -415,39 +417,127 @@ static bool is_request_lun_aligned(int64_t sector_num, int nb_sectors, return 1; } -static unsigned long *iscsi_allocationmap_init(IscsiLun *iscsilun) +static void iscsi_allocmap_free(IscsiLun *iscsilun) { - return bitmap_try_new(DIV_ROUND_UP(sector_lun2qemu(iscsilun->num_blocks, - iscsilun), - iscsilun->cluster_sectors)); + g_free(iscsilun->allocmap); + g_free(iscsilun->allocmap_valid); + iscsilun->allocmap = NULL; + iscsilun->allocmap_valid = NULL; } -static void iscsi_allocationmap_set(IscsiLun *iscsilun, int64_t sector_num, - int nb_sectors) + +static int iscsi_allocmap_init(IscsiLun *iscsilun, int open_flags) { - if (iscsilun->allocationmap == NULL) { - return; + iscsilun->allocmap_size = + DIV_ROUND_UP(sector_lun2qemu(iscsilun->num_blocks, iscsilun), + iscsilun->cluster_sectors); + + iscsilun->allocmap = bitmap_try_new(iscsilun->allocmap_size); + if (!iscsilun->allocmap) { + return -ENOMEM; + } + + if (open_flags & BDRV_O_NOCACHE) { + return 0; + } + + iscsilun->allocmap_valid = bitmap_try_new(iscsilun->allocmap_size); + if (!iscsilun->allocmap_valid) { + return -ENOMEM; } - bitmap_set(iscsilun->allocationmap, - sector_num / iscsilun->cluster_sectors, - DIV_ROUND_UP(nb_sectors, iscsilun->cluster_sectors)); + + return 0; } -static void iscsi_allocationmap_clear(IscsiLun *iscsilun, int64_t sector_num, - int nb_sectors) +static void +iscsi_allocmap_update(IscsiLun *iscsilun, int64_t sector_num, + int nb_sectors, bool allocated, bool valid) { int64_t cluster_num, nb_clusters; - if (iscsilun->allocationmap == NULL) { + + if (iscsilun->allocmap == NULL) { return; } cluster_num = DIV_ROUND_UP(sector_num, iscsilun->cluster_sectors); nb_clusters = (sector_num + nb_sectors) / iscsilun->cluster_sectors - cluster_num; - if (nb_clusters > 0) { - bitmap_clear(iscsilun->allocationmap, cluster_num, nb_clusters); + if (allocated) { + bitmap_set(iscsilun->allocmap, + sector_num / iscsilun->cluster_sectors, + DIV_ROUND_UP(nb_sectors, iscsilun->cluster_sectors)); + } else if (nb_clusters > 0) { + bitmap_clear(iscsilun->allocmap, cluster_num, nb_clusters); + } + + if (iscsilun->allocmap_valid == NULL) { + return; + } + if (valid) { + if (nb_clusters > 0) { + bitmap_set(iscsilun->allocmap_valid, cluster_num, nb_clusters); + } + } else { + bitmap_clear(iscsilun->allocmap_valid, + sector_num / iscsilun->cluster_sectors, + DIV_ROUND_UP(nb_sectors, iscsilun->cluster_sectors)); } } +static void +iscsi_allocmap_set_allocated(IscsiLun *iscsilun, int64_t sector_num, + int nb_sectors) +{ + iscsi_allocmap_update(iscsilun, sector_num, nb_sectors, true, true); +} + +static void +iscsi_allocmap_set_unallocated(IscsiLun *iscsilun, int64_t sector_num, + int nb_sectors) +{ + iscsi_allocmap_update(iscsilun, sector_num, nb_sectors, false, true); +} + +static void iscsi_allocmap_set_invalid(IscsiLun *iscsilun, int64_t sector_num, + int nb_sectors) +{ + iscsi_allocmap_update(iscsilun, sector_num, nb_sectors, false, false); +} + +static void iscsi_allocmap_invalidate(IscsiLun *iscsilun) +{ + if (iscsilun->allocmap) { + bitmap_zero(iscsilun->allocmap, iscsilun->allocmap_size); + } + if (iscsilun->allocmap_valid) { + bitmap_zero(iscsilun->allocmap_valid, iscsilun->allocmap_size); + } +} + +static inline bool +iscsi_allocmap_is_allocated(IscsiLun *iscsilun, int64_t sector_num, + int nb_sectors) +{ + unsigned long size; + if (iscsilun->allocmap == NULL) { + return true; + } + size = DIV_ROUND_UP(sector_num + nb_sectors, iscsilun->cluster_sectors); + return !(find_next_bit(iscsilun->allocmap, size, + sector_num / iscsilun->cluster_sectors) == size); +} + +static inline bool iscsi_allocmap_is_valid(IscsiLun *iscsilun, + int64_t sector_num, int nb_sectors) +{ + unsigned long size; + if (iscsilun->allocmap_valid == NULL) { + return false; + } + size = DIV_ROUND_UP(sector_num + nb_sectors, iscsilun->cluster_sectors); + return (find_next_zero_bit(iscsilun->allocmap_valid, size, + sector_num / iscsilun->cluster_sectors) == size); +} + static int coroutine_fn iscsi_co_writev_flags(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *iov, int flags) @@ -507,26 +597,16 @@ retry: } if (iTask.status != SCSI_STATUS_GOOD) { + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); return iTask.err_code; } - iscsi_allocationmap_set(iscsilun, sector_num, nb_sectors); + iscsi_allocmap_set_allocated(iscsilun, sector_num, nb_sectors); return 0; } -static bool iscsi_allocationmap_is_allocated(IscsiLun *iscsilun, - int64_t sector_num, int nb_sectors) -{ - unsigned long size; - if (iscsilun->allocationmap == NULL) { - return true; - } - size = DIV_ROUND_UP(sector_num + nb_sectors, iscsilun->cluster_sectors); - return !(find_next_bit(iscsilun->allocationmap, size, - sector_num / iscsilun->cluster_sectors) == size); -} static int64_t coroutine_fn iscsi_co_get_block_status(BlockDriverState *bs, int64_t sector_num, @@ -611,9 +691,9 @@ retry: } if (ret & BDRV_BLOCK_ZERO) { - iscsi_allocationmap_clear(iscsilun, sector_num, *pnum); + iscsi_allocmap_set_unallocated(iscsilun, sector_num, *pnum); } else { - iscsi_allocationmap_set(iscsilun, sector_num, *pnum); + iscsi_allocmap_set_allocated(iscsilun, sector_num, *pnum); } if (*pnum > nb_sectors) { @@ -629,7 +709,7 @@ out: return ret; } -static int coroutine_fn iscsi_co_readv(BlockDriverState *bs, + static int coroutine_fn iscsi_co_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *iov) { @@ -648,16 +728,25 @@ static int coroutine_fn iscsi_co_readv(BlockDriverState *bs, return -EINVAL; } - if (iscsilun->lbprz && nb_sectors >= ISCSI_CHECKALLOC_THRES && - !iscsi_allocationmap_is_allocated(iscsilun, sector_num, nb_sectors)) { - int64_t ret; + if (iscsi_allocmap_is_valid(iscsilun, sector_num, nb_sectors) && + !iscsi_allocmap_is_allocated(iscsilun, sector_num, nb_sectors)) { + qemu_iovec_memset(iov, 0, 0x00, iov->size); + return 0; + } + + if (nb_sectors >= ISCSI_CHECKALLOC_THRES && + !iscsi_allocmap_is_valid(iscsilun, sector_num, nb_sectors) && + !iscsi_allocmap_is_allocated(iscsilun, sector_num, nb_sectors)) { int pnum; BlockDriverState *file; - ret = iscsi_co_get_block_status(bs, sector_num, INT_MAX, &pnum, &file); + int64_t ret = iscsi_co_get_block_status(bs, + sector_num - sector_num % iscsilun->cluster_sectors, + INT_MAX, &pnum, &file); if (ret < 0) { return ret; } - if (ret & BDRV_BLOCK_ZERO && pnum >= nb_sectors) { + if (ret & BDRV_BLOCK_ZERO && + pnum >= nb_sectors + sector_num % iscsilun->cluster_sectors) { qemu_iovec_memset(iov, 0, 0x00, iov->size); return 0; } @@ -892,7 +981,6 @@ static BlockAIOCB *iscsi_aio_ioctl(BlockDriverState *bs, } iscsi_set_events(iscsilun); - return &acb->common; } @@ -963,7 +1051,7 @@ retry: return iTask.err_code; } - iscsi_allocationmap_clear(iscsilun, sector_num, nb_sectors); + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); return 0; } @@ -1053,13 +1141,14 @@ retry: } if (iTask.status != SCSI_STATUS_GOOD) { + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); return iTask.err_code; } if (flags & BDRV_REQ_MAY_UNMAP) { - iscsi_allocationmap_clear(iscsilun, sector_num, nb_sectors); + iscsi_allocmap_set_invalid(iscsilun, sector_num, nb_sectors); } else { - iscsi_allocationmap_set(iscsilun, sector_num, nb_sectors); + iscsi_allocmap_set_allocated(iscsilun, sector_num, nb_sectors); } return 0; @@ -1633,10 +1722,7 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags, iscsilun->cluster_sectors = (iscsilun->bl.opt_unmap_gran * iscsilun->block_size) >> BDRV_SECTOR_BITS; if (iscsilun->lbprz) { - iscsilun->allocationmap = iscsi_allocationmap_init(iscsilun); - if (iscsilun->allocationmap == NULL) { - ret = -ENOMEM; - } + ret = iscsi_allocmap_init(iscsilun, bs->open_flags); } } @@ -1673,7 +1759,7 @@ static void iscsi_close(BlockDriverState *bs) } iscsi_destroy_context(iscsi); g_free(iscsilun->zeroblock); - g_free(iscsilun->allocationmap); + iscsi_allocmap_free(iscsilun); memset(iscsilun, 0, sizeof(IscsiLun)); } @@ -1750,9 +1836,9 @@ static int iscsi_truncate(BlockDriverState *bs, int64_t offset) return -EINVAL; } - if (iscsilun->allocationmap != NULL) { - g_free(iscsilun->allocationmap); - iscsilun->allocationmap = iscsi_allocationmap_init(iscsilun); + if (iscsilun->allocmap != NULL) { + iscsi_allocmap_free(iscsilun); + iscsi_allocmap_init(iscsilun, bs->open_flags); } return 0; @@ -1812,6 +1898,13 @@ static int iscsi_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) return 0; } +static void iscsi_invalidate_cache(BlockDriverState *bs, + Error **errp) +{ + IscsiLun *iscsilun = bs->opaque; + iscsi_allocmap_invalidate(iscsilun); +} + static QemuOptsList iscsi_create_opts = { .name = "iscsi-create-opts", .head = QTAILQ_HEAD_INITIALIZER(iscsi_create_opts.head), @@ -1836,6 +1929,7 @@ static BlockDriver bdrv_iscsi = { .bdrv_create = iscsi_create, .create_opts = &iscsi_create_opts, .bdrv_reopen_prepare = iscsi_reopen_prepare, + .bdrv_invalidate_cache = iscsi_invalidate_cache, .bdrv_getlength = iscsi_getlength, .bdrv_get_info = iscsi_get_info,
until now the allocation map was used only as a hint if a cluster is allocated or not. If a block was not allocated (or Qemu had no info about the allocation status) a get_block_status call was issued to check the allocation status and possibly avoid a subsequent read of unallocated sectors. If a block known to be allocated the get_block_status call was omitted. In the other case a get_block_status call was issued before every read to avoid the necessity for a consistent allocation map. To avoid the potential overhead of calling get_block_status for each and every read request this took only place for the bigger requests. This patch enhances this mechanism to cache the allocation status and avoid calling get_block_status for blocks where the allocation status has been queried before. This allows for bypassing the read request even for smaller requests and additionally omits calling get_block_status for known to be unallocated blocks. Signed-off-by: Peter Lieven <pl@kamp.de> --- block/iscsi.c | 194 +++++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 144 insertions(+), 50 deletions(-)