| Message ID | 157969069360.174869.18184061012552778480.stgit@localhost.localdomain (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: Introduce REQ_ALLOCATE flag for REQ_OP_WRITE_ZEROES | expand |
On 1/22/20 6:58 PM, Kirill Tkhai wrote: > This adds support for REQ_ALLOCATE extension of REQ_OP_WRITE_ZEROES > operation, which encourages a block device driver to just allocate > blocks (or mark them allocated) instead of actual blocks zeroing. > REQ_ALLOCATE is aimed to be used for network filesystems providing > a block device interface. Also, block devices, which map a file > on other filesystem (like loop), may use this for less fragmentation > and batching fallocate() requests. Hypervisors like QEMU may > introduce optimizations of clusters allocations based on this. > > BLKDEV_ZERO_ALLOCATE is a new corresponding flag for > blkdev_issue_zeroout(). > > Stacking devices start from zero max_allocate_sectors limit for now, > and the support is going to be implemented separate for each device > in the future. > > Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> > --- > block/blk-lib.c | 17 ++++++++++------- > block/blk-settings.c | 4 ++++ > fs/block_dev.c | 4 ++++ > include/linux/blk_types.h | 5 ++++- > include/linux/blkdev.h | 13 ++++++++++--- > 5 files changed, 32 insertions(+), 11 deletions(-) > This patch and following two are looks fine to me. Feel free to add. Reviewed-by: Bob Liu <bob.liu@oracle.com> > diff --git a/block/blk-lib.c b/block/blk-lib.c > index 3e38c93cfc53..9cd6f86523ba 100644 > --- a/block/blk-lib.c > +++ b/block/blk-lib.c > @@ -214,7 +214,7 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev, > struct bio **biop, unsigned flags) > { > struct bio *bio = *biop; > - unsigned int max_write_zeroes_sectors; > + unsigned int max_write_zeroes_sectors, req_flags = 0; > struct request_queue *q = bdev_get_queue(bdev); > > if (!q) > @@ -224,18 +224,21 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev, > return -EPERM; > > /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */ > - max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev, 0); > + max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev, flags); > > if (max_write_zeroes_sectors == 0) > return -EOPNOTSUPP; > > + if (flags & BLKDEV_ZERO_NOUNMAP) > + req_flags |= REQ_NOUNMAP; > + if (flags & BLKDEV_ZERO_ALLOCATE) > + req_flags |= REQ_ALLOCATE|REQ_NOUNMAP; > + > while (nr_sects) { > bio = blk_next_bio(bio, 0, gfp_mask); > bio->bi_iter.bi_sector = sector; > bio_set_dev(bio, bdev); > - bio->bi_opf = REQ_OP_WRITE_ZEROES; > - if (flags & BLKDEV_ZERO_NOUNMAP) > - bio->bi_opf |= REQ_NOUNMAP; > + bio->bi_opf = REQ_OP_WRITE_ZEROES | req_flags; > > if (nr_sects > max_write_zeroes_sectors) { > bio->bi_iter.bi_size = max_write_zeroes_sectors << 9; > @@ -362,7 +365,7 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, > sector_t bs_mask; > struct bio *bio; > struct blk_plug plug; > - bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev, 0); > + bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev, flags); > > bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; > if ((sector | nr_sects) & bs_mask) > @@ -391,7 +394,7 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, > try_write_zeroes = false; > goto retry; > } > - if (!bdev_write_zeroes_sectors(bdev, 0)) { > + if (!bdev_write_zeroes_sectors(bdev, flags)) { > /* > * Zeroing offload support was indicated, but the > * device reported ILLEGAL REQUEST (for some devices > diff --git a/block/blk-settings.c b/block/blk-settings.c > index c8eda2e7b91e..8d5df9d37239 100644 > --- a/block/blk-settings.c > +++ b/block/blk-settings.c > @@ -48,6 +48,7 @@ void blk_set_default_limits(struct queue_limits *lim) > lim->chunk_sectors = 0; > lim->max_write_same_sectors = 0; > lim->max_write_zeroes_sectors = 0; > + lim->max_allocate_sectors = 0; > lim->max_discard_sectors = 0; > lim->max_hw_discard_sectors = 0; > lim->discard_granularity = 0; > @@ -83,6 +84,7 @@ void blk_set_stacking_limits(struct queue_limits *lim) > lim->max_dev_sectors = UINT_MAX; > lim->max_write_same_sectors = UINT_MAX; > lim->max_write_zeroes_sectors = UINT_MAX; > + lim->max_allocate_sectors = 0; > } > EXPORT_SYMBOL(blk_set_stacking_limits); > > @@ -506,6 +508,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, > b->max_write_same_sectors); > t->max_write_zeroes_sectors = min(t->max_write_zeroes_sectors, > b->max_write_zeroes_sectors); > + t->max_allocate_sectors = min(t->max_allocate_sectors, > + b->max_allocate_sectors); > t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); > > t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, > diff --git a/fs/block_dev.c b/fs/block_dev.c > index 69bf2fb6f7cd..1ffef894b3bd 100644 > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -2122,6 +2122,10 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start, > error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, > GFP_KERNEL, BLKDEV_ZERO_NOFALLBACK); > break; > + case FALLOC_FL_KEEP_SIZE: > + error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, > + GFP_KERNEL, BLKDEV_ZERO_ALLOCATE | BLKDEV_ZERO_NOFALLBACK); > + break; > case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: > error = blkdev_issue_discard(bdev, start >> 9, len >> 9, > GFP_KERNEL, 0); > diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h > index 70254ae11769..86accd2caa4e 100644 > --- a/include/linux/blk_types.h > +++ b/include/linux/blk_types.h > @@ -335,7 +335,9 @@ enum req_flag_bits { > > /* command specific flags for REQ_OP_WRITE_ZEROES: */ > __REQ_NOUNMAP, /* do not free blocks when zeroing */ > - > + __REQ_ALLOCATE, /* only notify about allocated blocks, > + * and do not actually zero them > + */ > __REQ_HIPRI, > > /* for driver use */ > @@ -362,6 +364,7 @@ enum req_flag_bits { > #define REQ_CGROUP_PUNT (1ULL << __REQ_CGROUP_PUNT) > > #define REQ_NOUNMAP (1ULL << __REQ_NOUNMAP) > +#define REQ_ALLOCATE (1ULL << __REQ_ALLOCATE) > #define REQ_HIPRI (1ULL << __REQ_HIPRI) > > #define REQ_DRV (1ULL << __REQ_DRV) > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index 264202fa3bf8..20c94a7f9411 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -337,6 +337,7 @@ struct queue_limits { > unsigned int max_hw_discard_sectors; > unsigned int max_write_same_sectors; > unsigned int max_write_zeroes_sectors; > + unsigned int max_allocate_sectors; > unsigned int discard_granularity; > unsigned int discard_alignment; > > @@ -991,6 +992,8 @@ static inline struct bio_vec req_bvec(struct request *rq) > static inline unsigned int blk_queue_get_max_write_zeroes_sectors( > struct request_queue *q, unsigned int op_flags) > { > + if (op_flags & REQ_ALLOCATE) > + return q->limits.max_allocate_sectors; > return q->limits.max_write_zeroes_sectors; > } > > @@ -1227,6 +1230,7 @@ extern int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, > > #define BLKDEV_ZERO_NOUNMAP (1 << 0) /* do not free blocks */ > #define BLKDEV_ZERO_NOFALLBACK (1 << 1) /* don't write explicit zeroes */ > +#define BLKDEV_ZERO_ALLOCATE (1 << 2) /* allocate range of blocks */ > > extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, > sector_t nr_sects, gfp_t gfp_mask, struct bio **biop, > @@ -1431,10 +1435,13 @@ static inline unsigned int bdev_write_zeroes_sectors(struct block_device *bdev, > { > struct request_queue *q = bdev_get_queue(bdev); > > - if (q) > - return q->limits.max_write_zeroes_sectors; > + if (!q) > + return 0; > > - return 0; > + if (flags & BLKDEV_ZERO_ALLOCATE) > + return q->limits.max_allocate_sectors; > + else > + return q->limits.max_write_zeroes_sectors; > } > > static inline enum blk_zoned_model bdev_zoned_model(struct block_device *bdev) > >
On 25.01.2020 06:18, Bob Liu wrote: > On 1/22/20 6:58 PM, Kirill Tkhai wrote: >> This adds support for REQ_ALLOCATE extension of REQ_OP_WRITE_ZEROES >> operation, which encourages a block device driver to just allocate >> blocks (or mark them allocated) instead of actual blocks zeroing. >> REQ_ALLOCATE is aimed to be used for network filesystems providing >> a block device interface. Also, block devices, which map a file >> on other filesystem (like loop), may use this for less fragmentation >> and batching fallocate() requests. Hypervisors like QEMU may >> introduce optimizations of clusters allocations based on this. >> >> BLKDEV_ZERO_ALLOCATE is a new corresponding flag for >> blkdev_issue_zeroout(). >> >> Stacking devices start from zero max_allocate_sectors limit for now, >> and the support is going to be implemented separate for each device >> in the future. >> >> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> >> --- >> block/blk-lib.c | 17 ++++++++++------- >> block/blk-settings.c | 4 ++++ >> fs/block_dev.c | 4 ++++ >> include/linux/blk_types.h | 5 ++++- >> include/linux/blkdev.h | 13 ++++++++++--- >> 5 files changed, 32 insertions(+), 11 deletions(-) >> > > This patch and following two are looks fine to me. > Feel free to add. > Reviewed-by: Bob Liu <bob.liu@oracle.com> Thank you, Bob. Kirill >> diff --git a/block/blk-lib.c b/block/blk-lib.c >> index 3e38c93cfc53..9cd6f86523ba 100644 >> --- a/block/blk-lib.c >> +++ b/block/blk-lib.c >> @@ -214,7 +214,7 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev, >> struct bio **biop, unsigned flags) >> { >> struct bio *bio = *biop; >> - unsigned int max_write_zeroes_sectors; >> + unsigned int max_write_zeroes_sectors, req_flags = 0; >> struct request_queue *q = bdev_get_queue(bdev); >> >> if (!q) >> @@ -224,18 +224,21 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev, >> return -EPERM; >> >> /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */ >> - max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev, 0); >> + max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev, flags); >> >> if (max_write_zeroes_sectors == 0) >> return -EOPNOTSUPP; >> >> + if (flags & BLKDEV_ZERO_NOUNMAP) >> + req_flags |= REQ_NOUNMAP; >> + if (flags & BLKDEV_ZERO_ALLOCATE) >> + req_flags |= REQ_ALLOCATE|REQ_NOUNMAP; >> + >> while (nr_sects) { >> bio = blk_next_bio(bio, 0, gfp_mask); >> bio->bi_iter.bi_sector = sector; >> bio_set_dev(bio, bdev); >> - bio->bi_opf = REQ_OP_WRITE_ZEROES; >> - if (flags & BLKDEV_ZERO_NOUNMAP) >> - bio->bi_opf |= REQ_NOUNMAP; >> + bio->bi_opf = REQ_OP_WRITE_ZEROES | req_flags; >> >> if (nr_sects > max_write_zeroes_sectors) { >> bio->bi_iter.bi_size = max_write_zeroes_sectors << 9; >> @@ -362,7 +365,7 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, >> sector_t bs_mask; >> struct bio *bio; >> struct blk_plug plug; >> - bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev, 0); >> + bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev, flags); >> >> bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; >> if ((sector | nr_sects) & bs_mask) >> @@ -391,7 +394,7 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, >> try_write_zeroes = false; >> goto retry; >> } >> - if (!bdev_write_zeroes_sectors(bdev, 0)) { >> + if (!bdev_write_zeroes_sectors(bdev, flags)) { >> /* >> * Zeroing offload support was indicated, but the >> * device reported ILLEGAL REQUEST (for some devices >> diff --git a/block/blk-settings.c b/block/blk-settings.c >> index c8eda2e7b91e..8d5df9d37239 100644 >> --- a/block/blk-settings.c >> +++ b/block/blk-settings.c >> @@ -48,6 +48,7 @@ void blk_set_default_limits(struct queue_limits *lim) >> lim->chunk_sectors = 0; >> lim->max_write_same_sectors = 0; >> lim->max_write_zeroes_sectors = 0; >> + lim->max_allocate_sectors = 0; >> lim->max_discard_sectors = 0; >> lim->max_hw_discard_sectors = 0; >> lim->discard_granularity = 0; >> @@ -83,6 +84,7 @@ void blk_set_stacking_limits(struct queue_limits *lim) >> lim->max_dev_sectors = UINT_MAX; >> lim->max_write_same_sectors = UINT_MAX; >> lim->max_write_zeroes_sectors = UINT_MAX; >> + lim->max_allocate_sectors = 0; >> } >> EXPORT_SYMBOL(blk_set_stacking_limits); >> >> @@ -506,6 +508,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, >> b->max_write_same_sectors); >> t->max_write_zeroes_sectors = min(t->max_write_zeroes_sectors, >> b->max_write_zeroes_sectors); >> + t->max_allocate_sectors = min(t->max_allocate_sectors, >> + b->max_allocate_sectors); >> t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); >> >> t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, >> diff --git a/fs/block_dev.c b/fs/block_dev.c >> index 69bf2fb6f7cd..1ffef894b3bd 100644 >> --- a/fs/block_dev.c >> +++ b/fs/block_dev.c >> @@ -2122,6 +2122,10 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start, >> error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, >> GFP_KERNEL, BLKDEV_ZERO_NOFALLBACK); >> break; >> + case FALLOC_FL_KEEP_SIZE: >> + error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, >> + GFP_KERNEL, BLKDEV_ZERO_ALLOCATE | BLKDEV_ZERO_NOFALLBACK); >> + break; >> case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: >> error = blkdev_issue_discard(bdev, start >> 9, len >> 9, >> GFP_KERNEL, 0); >> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h >> index 70254ae11769..86accd2caa4e 100644 >> --- a/include/linux/blk_types.h >> +++ b/include/linux/blk_types.h >> @@ -335,7 +335,9 @@ enum req_flag_bits { >> >> /* command specific flags for REQ_OP_WRITE_ZEROES: */ >> __REQ_NOUNMAP, /* do not free blocks when zeroing */ >> - >> + __REQ_ALLOCATE, /* only notify about allocated blocks, >> + * and do not actually zero them >> + */ >> __REQ_HIPRI, >> >> /* for driver use */ >> @@ -362,6 +364,7 @@ enum req_flag_bits { >> #define REQ_CGROUP_PUNT (1ULL << __REQ_CGROUP_PUNT) >> >> #define REQ_NOUNMAP (1ULL << __REQ_NOUNMAP) >> +#define REQ_ALLOCATE (1ULL << __REQ_ALLOCATE) >> #define REQ_HIPRI (1ULL << __REQ_HIPRI) >> >> #define REQ_DRV (1ULL << __REQ_DRV) >> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h >> index 264202fa3bf8..20c94a7f9411 100644 >> --- a/include/linux/blkdev.h >> +++ b/include/linux/blkdev.h >> @@ -337,6 +337,7 @@ struct queue_limits { >> unsigned int max_hw_discard_sectors; >> unsigned int max_write_same_sectors; >> unsigned int max_write_zeroes_sectors; >> + unsigned int max_allocate_sectors; >> unsigned int discard_granularity; >> unsigned int discard_alignment; >> >> @@ -991,6 +992,8 @@ static inline struct bio_vec req_bvec(struct request *rq) >> static inline unsigned int blk_queue_get_max_write_zeroes_sectors( >> struct request_queue *q, unsigned int op_flags) >> { >> + if (op_flags & REQ_ALLOCATE) >> + return q->limits.max_allocate_sectors; >> return q->limits.max_write_zeroes_sectors; >> } >> >> @@ -1227,6 +1230,7 @@ extern int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, >> >> #define BLKDEV_ZERO_NOUNMAP (1 << 0) /* do not free blocks */ >> #define BLKDEV_ZERO_NOFALLBACK (1 << 1) /* don't write explicit zeroes */ >> +#define BLKDEV_ZERO_ALLOCATE (1 << 2) /* allocate range of blocks */ >> >> extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, >> sector_t nr_sects, gfp_t gfp_mask, struct bio **biop, >> @@ -1431,10 +1435,13 @@ static inline unsigned int bdev_write_zeroes_sectors(struct block_device *bdev, >> { >> struct request_queue *q = bdev_get_queue(bdev); >> >> - if (q) >> - return q->limits.max_write_zeroes_sectors; >> + if (!q) >> + return 0; >> >> - return 0; >> + if (flags & BLKDEV_ZERO_ALLOCATE) >> + return q->limits.max_allocate_sectors; >> + else >> + return q->limits.max_write_zeroes_sectors; >> } >> >> static inline enum blk_zoned_model bdev_zoned_model(struct block_device *bdev) >> >> >
diff --git a/block/blk-lib.c b/block/blk-lib.c index 3e38c93cfc53..9cd6f86523ba 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -214,7 +214,7 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev, struct bio **biop, unsigned flags) { struct bio *bio = *biop; - unsigned int max_write_zeroes_sectors; + unsigned int max_write_zeroes_sectors, req_flags = 0; struct request_queue *q = bdev_get_queue(bdev); if (!q) @@ -224,18 +224,21 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev, return -EPERM; /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */ - max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev, 0); + max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev, flags); if (max_write_zeroes_sectors == 0) return -EOPNOTSUPP; + if (flags & BLKDEV_ZERO_NOUNMAP) + req_flags |= REQ_NOUNMAP; + if (flags & BLKDEV_ZERO_ALLOCATE) + req_flags |= REQ_ALLOCATE|REQ_NOUNMAP; + while (nr_sects) { bio = blk_next_bio(bio, 0, gfp_mask); bio->bi_iter.bi_sector = sector; bio_set_dev(bio, bdev); - bio->bi_opf = REQ_OP_WRITE_ZEROES; - if (flags & BLKDEV_ZERO_NOUNMAP) - bio->bi_opf |= REQ_NOUNMAP; + bio->bi_opf = REQ_OP_WRITE_ZEROES | req_flags; if (nr_sects > max_write_zeroes_sectors) { bio->bi_iter.bi_size = max_write_zeroes_sectors << 9; @@ -362,7 +365,7 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, sector_t bs_mask; struct bio *bio; struct blk_plug plug; - bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev, 0); + bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev, flags); bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; if ((sector | nr_sects) & bs_mask) @@ -391,7 +394,7 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, try_write_zeroes = false; goto retry; } - if (!bdev_write_zeroes_sectors(bdev, 0)) { + if (!bdev_write_zeroes_sectors(bdev, flags)) { /* * Zeroing offload support was indicated, but the * device reported ILLEGAL REQUEST (for some devices diff --git a/block/blk-settings.c b/block/blk-settings.c index c8eda2e7b91e..8d5df9d37239 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -48,6 +48,7 @@ void blk_set_default_limits(struct queue_limits *lim) lim->chunk_sectors = 0; lim->max_write_same_sectors = 0; lim->max_write_zeroes_sectors = 0; + lim->max_allocate_sectors = 0; lim->max_discard_sectors = 0; lim->max_hw_discard_sectors = 0; lim->discard_granularity = 0; @@ -83,6 +84,7 @@ void blk_set_stacking_limits(struct queue_limits *lim) lim->max_dev_sectors = UINT_MAX; lim->max_write_same_sectors = UINT_MAX; lim->max_write_zeroes_sectors = UINT_MAX; + lim->max_allocate_sectors = 0; } EXPORT_SYMBOL(blk_set_stacking_limits); @@ -506,6 +508,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, b->max_write_same_sectors); t->max_write_zeroes_sectors = min(t->max_write_zeroes_sectors, b->max_write_zeroes_sectors); + t->max_allocate_sectors = min(t->max_allocate_sectors, + b->max_allocate_sectors); t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, diff --git a/fs/block_dev.c b/fs/block_dev.c index 69bf2fb6f7cd..1ffef894b3bd 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -2122,6 +2122,10 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start, error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL, BLKDEV_ZERO_NOFALLBACK); break; + case FALLOC_FL_KEEP_SIZE: + error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, + GFP_KERNEL, BLKDEV_ZERO_ALLOCATE | BLKDEV_ZERO_NOFALLBACK); + break; case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: error = blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL, 0); diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 70254ae11769..86accd2caa4e 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -335,7 +335,9 @@ enum req_flag_bits { /* command specific flags for REQ_OP_WRITE_ZEROES: */ __REQ_NOUNMAP, /* do not free blocks when zeroing */ - + __REQ_ALLOCATE, /* only notify about allocated blocks, + * and do not actually zero them + */ __REQ_HIPRI, /* for driver use */ @@ -362,6 +364,7 @@ enum req_flag_bits { #define REQ_CGROUP_PUNT (1ULL << __REQ_CGROUP_PUNT) #define REQ_NOUNMAP (1ULL << __REQ_NOUNMAP) +#define REQ_ALLOCATE (1ULL << __REQ_ALLOCATE) #define REQ_HIPRI (1ULL << __REQ_HIPRI) #define REQ_DRV (1ULL << __REQ_DRV) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 264202fa3bf8..20c94a7f9411 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -337,6 +337,7 @@ struct queue_limits { unsigned int max_hw_discard_sectors; unsigned int max_write_same_sectors; unsigned int max_write_zeroes_sectors; + unsigned int max_allocate_sectors; unsigned int discard_granularity; unsigned int discard_alignment; @@ -991,6 +992,8 @@ static inline struct bio_vec req_bvec(struct request *rq) static inline unsigned int blk_queue_get_max_write_zeroes_sectors( struct request_queue *q, unsigned int op_flags) { + if (op_flags & REQ_ALLOCATE) + return q->limits.max_allocate_sectors; return q->limits.max_write_zeroes_sectors; } @@ -1227,6 +1230,7 @@ extern int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, #define BLKDEV_ZERO_NOUNMAP (1 << 0) /* do not free blocks */ #define BLKDEV_ZERO_NOFALLBACK (1 << 1) /* don't write explicit zeroes */ +#define BLKDEV_ZERO_ALLOCATE (1 << 2) /* allocate range of blocks */ extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask, struct bio **biop, @@ -1431,10 +1435,13 @@ static inline unsigned int bdev_write_zeroes_sectors(struct block_device *bdev, { struct request_queue *q = bdev_get_queue(bdev); - if (q) - return q->limits.max_write_zeroes_sectors; + if (!q) + return 0; - return 0; + if (flags & BLKDEV_ZERO_ALLOCATE) + return q->limits.max_allocate_sectors; + else + return q->limits.max_write_zeroes_sectors; } static inline enum blk_zoned_model bdev_zoned_model(struct block_device *bdev)
This adds support for REQ_ALLOCATE extension of REQ_OP_WRITE_ZEROES operation, which encourages a block device driver to just allocate blocks (or mark them allocated) instead of actual blocks zeroing. REQ_ALLOCATE is aimed to be used for network filesystems providing a block device interface. Also, block devices, which map a file on other filesystem (like loop), may use this for less fragmentation and batching fallocate() requests. Hypervisors like QEMU may introduce optimizations of clusters allocations based on this. BLKDEV_ZERO_ALLOCATE is a new corresponding flag for blkdev_issue_zeroout(). Stacking devices start from zero max_allocate_sectors limit for now, and the support is going to be implemented separate for each device in the future. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> --- block/blk-lib.c | 17 ++++++++++------- block/blk-settings.c | 4 ++++ fs/block_dev.c | 4 ++++ include/linux/blk_types.h | 5 ++++- include/linux/blkdev.h | 13 ++++++++++--- 5 files changed, 32 insertions(+), 11 deletions(-)