[PATCH RFC 1/8] block: Introduce provisioning primitives

From: Sarthak Kukreti
Date: Thu Sep 15 2022 - 12:48:53 EST

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From: Sarthak Kukreti <sarthakkukreti@xxxxxxxxxxxx>

Introduce block request REQ_OP_PROVISION. The intent of this request
is to request underlying storage to preallocate disk space for the given
block range. Block device that support this capability will export
a provision limit within their request queues.

Signed-off-by: Sarthak Kukreti <sarthakkukreti@xxxxxxxxxxxx>
---
block/blk-core.c | 5 ++++
block/blk-lib.c | 55 +++++++++++++++++++++++++++++++++++++++
block/blk-merge.c | 17 ++++++++++++
block/blk-settings.c | 19 ++++++++++++++
block/blk-sysfs.c | 8 ++++++
block/bounce.c | 1 +
include/linux/bio.h | 6 +++--
include/linux/blk_types.h | 5 +++-
include/linux/blkdev.h | 16 ++++++++++++
9 files changed, 129 insertions(+), 3 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index a0d1104c5590..affefbaba1cd 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -125,6 +125,7 @@ static const char *const blk_op_name[] = {
REQ_OP_NAME(WRITE_ZEROES),
REQ_OP_NAME(DRV_IN),
REQ_OP_NAME(DRV_OUT),
+ REQ_OP_NAME(PROVISION)
};
#undef REQ_OP_NAME

@@ -776,6 +777,10 @@ void submit_bio_noacct(struct bio *bio)
if (!q->limits.max_write_zeroes_sectors)
goto not_supported;
break;
+ case REQ_OP_PROVISION:
+ if (!q->limits.max_provision_sectors)
+ goto not_supported;
+ break;
default:
break;
}
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 67e6dbc1ae81..dc11ed29b523 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -338,3 +338,58 @@ int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
return ret;
}
EXPORT_SYMBOL(blkdev_issue_secure_erase);
+
+/**
+ * blkdev_issue_provision - provision a block range
+ * @bdev: blockdev to write
+ * @sector: start sector
+ * @nr_sects: number of sectors to provision
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ *
+ * Description:
+ * Issues a provision request to the block device for the range of sectors.
+ * For thinly provisioned block devices, this acts as a signal for the
+ * underlying storage pool to allocate space for this block range.
+ */
+int blkdev_issue_provision(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp)
+{
+ sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
+ unsigned int max_sectors = bdev_max_provision_sectors(bdev);
+ struct bio *bio = NULL;
+ struct blk_plug plug;
+ int ret = 0;
+
+ if (max_sectors == 0)
+ return -EOPNOTSUPP;
+ if ((sector | nr_sects) & bs_mask)
+ return -EINVAL;
+ if (bdev_read_only(bdev))
+ return -EPERM;
+
+ blk_start_plug(&plug);
+ for (;;) {
+ unsigned int req_sects = min_t(sector_t, nr_sects, max_sectors);
+
+ bio = blk_next_bio(bio, bdev, 0, REQ_OP_PROVISION, gfp);
+ bio->bi_iter.bi_sector = sector;
+ bio->bi_iter.bi_size = req_sects << SECTOR_SHIFT;
+ bio_set_dev(bio, bdev);
+ bio_set_op_attrs(bio, REQ_OP_PROVISION, 0);
+
+ sector += req_sects;
+ nr_sects -= req_sects;
+ if (!nr_sects) {
+ ret = submit_bio_wait(bio);
+ if (ret == -EOPNOTSUPP)
+ ret = 0;
+ bio_put(bio);
+ break;
+ }
+ cond_resched();
+ }
+ blk_finish_plug(&plug);
+
+ return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_provision);
diff --git a/block/blk-merge.c b/block/blk-merge.c
index ff04e9290715..ee8dd07b24fe 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -156,6 +156,20 @@ static struct bio *bio_split_write_zeroes(struct bio *bio,
return bio_split(bio, lim->max_write_zeroes_sectors, GFP_NOIO, bs);
}

+static struct bio *bio_split_provision(struct bio *bio,
+ struct queue_limits *lim, unsigned *nsegs, struct bio_set *bs)
+{
+ *nsegs = 0;
+
+ if (!lim->max_provision_sectors)
+ return NULL;
+
+ if (bio_sectors(bio) <= lim->max_provision_sectors)
+ return NULL;
+
+ return bio_split(bio, lim->max_provision_sectors, GFP_NOIO, bs);
+}
+
/*
* Return the maximum number of sectors from the start of a bio that may be
* submitted as a single request to a block device. If enough sectors remain,
@@ -345,6 +359,9 @@ struct bio *__bio_split_to_limits(struct bio *bio, struct queue_limits *lim,
case REQ_OP_WRITE_ZEROES:
split = bio_split_write_zeroes(bio, lim, nr_segs, bs);
break;
+ case REQ_OP_PROVISION:
+ split = bio_split_provision(bio, lim, nr_segs, bs);
+ break;
default:
split = bio_split_rw(bio, lim, nr_segs, bs,
get_max_io_size(bio, lim) << SECTOR_SHIFT);
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 8bb9eef5310e..be79ad68b330 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -57,6 +57,7 @@ void blk_set_default_limits(struct queue_limits *lim)
lim->misaligned = 0;
lim->zoned = BLK_ZONED_NONE;
lim->zone_write_granularity = 0;
+ lim->max_provision_sectors = 0;
}
EXPORT_SYMBOL(blk_set_default_limits);

@@ -81,6 +82,7 @@ void blk_set_stacking_limits(struct queue_limits *lim)
lim->max_dev_sectors = UINT_MAX;
lim->max_write_zeroes_sectors = UINT_MAX;
lim->max_zone_append_sectors = UINT_MAX;
+ lim->max_provision_sectors = UINT_MAX;
}
EXPORT_SYMBOL(blk_set_stacking_limits);

@@ -202,6 +204,20 @@ void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
}
EXPORT_SYMBOL(blk_queue_max_write_zeroes_sectors);

+/**
+ * blk_queue_max_provision_sectors - set max sectors for a single provision
+ *
+ * @q: the request queue for the device
+ * @max_provision_sectors: maximum number of sectors to provision per command
+ **/
+
+void blk_queue_max_provision_sectors(struct request_queue *q,
+ unsigned int max_provision_sectors)
+{
+ q->limits.max_provision_sectors = max_provision_sectors;
+}
+EXPORT_SYMBOL(blk_queue_max_provision_sectors);
+
/**
* blk_queue_max_zone_append_sectors - set max sectors for a single zone append
* @q: the request queue for the device
@@ -572,6 +588,9 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
t->max_segment_size = min_not_zero(t->max_segment_size,
b->max_segment_size);

+ t->max_provision_sectors = min_not_zero(t->max_provision_sectors,
+ b->max_provision_sectors);
+
t->misaligned |= b->misaligned;

alignment = queue_limit_alignment_offset(b, start);
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index e1f009aba6fd..912159518322 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -131,6 +131,12 @@ static ssize_t queue_max_discard_segments_show(struct request_queue *q,
return queue_var_show(queue_max_discard_segments(q), page);
}

+static ssize_t queue_max_provision_sectors_show(struct request_queue *q,
+ char *page)
+{
+ return queue_var_show(queue_max_provision_sectors(q), (page));
+}
+
static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
{
return queue_var_show(q->limits.max_integrity_segments, page);
@@ -586,6 +592,7 @@ QUEUE_RO_ENTRY(queue_io_min, "minimum_io_size");
QUEUE_RO_ENTRY(queue_io_opt, "optimal_io_size");

QUEUE_RO_ENTRY(queue_max_discard_segments, "max_discard_segments");
+QUEUE_RO_ENTRY(queue_max_provision_sectors, "max_provision_sectors");
QUEUE_RO_ENTRY(queue_discard_granularity, "discard_granularity");
QUEUE_RO_ENTRY(queue_discard_max_hw, "discard_max_hw_bytes");
QUEUE_RW_ENTRY(queue_discard_max, "discard_max_bytes");
@@ -635,6 +642,7 @@ static struct attribute *queue_attrs[] = {
&queue_max_sectors_entry.attr,
&queue_max_segments_entry.attr,
&queue_max_discard_segments_entry.attr,
+ &queue_max_provision_sectors_entry.attr,
&queue_max_integrity_segments_entry.attr,
&queue_max_segment_size_entry.attr,
&elv_iosched_entry.attr,
diff --git a/block/bounce.c b/block/bounce.c
index 7cfcb242f9a1..ab9d8723ae64 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -176,6 +176,7 @@ static struct bio *bounce_clone_bio(struct bio *bio_src)
case REQ_OP_DISCARD:
case REQ_OP_SECURE_ERASE:
case REQ_OP_WRITE_ZEROES:
+ case REQ_OP_PROVISION:
break;
default:
bio_for_each_segment(bv, bio_src, iter)
diff --git a/include/linux/bio.h b/include/linux/bio.h
index ca22b06700a9..3d5af770b90a 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -55,7 +55,8 @@ static inline bool bio_has_data(struct bio *bio)
bio->bi_iter.bi_size &&
bio_op(bio) != REQ_OP_DISCARD &&
bio_op(bio) != REQ_OP_SECURE_ERASE &&
- bio_op(bio) != REQ_OP_WRITE_ZEROES)
+ bio_op(bio) != REQ_OP_WRITE_ZEROES &&
+ bio_op(bio) != REQ_OP_PROVISION)
return true;

return false;
@@ -65,7 +66,8 @@ static inline bool bio_no_advance_iter(const struct bio *bio)
{
return bio_op(bio) == REQ_OP_DISCARD ||
bio_op(bio) == REQ_OP_SECURE_ERASE ||
- bio_op(bio) == REQ_OP_WRITE_ZEROES;
+ bio_op(bio) == REQ_OP_WRITE_ZEROES ||
+ bio_op(bio) == REQ_OP_PROVISION;
}

static inline void *bio_data(struct bio *bio)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 1ef99790f6ed..c6e9823c1542 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -386,7 +386,10 @@ enum req_op {
REQ_OP_DRV_IN = (__force blk_opf_t)34,
REQ_OP_DRV_OUT = (__force blk_opf_t)35,

- REQ_OP_LAST = (__force blk_opf_t)36,
+ /* request device to provision block */
+ REQ_OP_PROVISION = (__force blk_opf_t)37,
+
+ REQ_OP_LAST = (__force blk_opf_t)38,
};

enum req_flag_bits {
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 84b13fdd34a7..a58496d3f922 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -302,6 +302,7 @@ struct queue_limits {
unsigned int discard_granularity;
unsigned int discard_alignment;
unsigned int zone_write_granularity;
+ unsigned int max_provision_sectors;

unsigned short max_segments;
unsigned short max_integrity_segments;
@@ -931,6 +932,8 @@ extern void blk_queue_max_discard_sectors(struct request_queue *q,
unsigned int max_discard_sectors);
extern void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
unsigned int max_write_same_sectors);
+extern void blk_queue_max_provision_sectors(struct request_queue *q,
+ unsigned int max_provision_sectors);
extern void blk_queue_logical_block_size(struct request_queue *, unsigned int);
extern void blk_queue_max_zone_append_sectors(struct request_queue *q,
unsigned int max_zone_append_sectors);
@@ -1071,6 +1074,9 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp);

+extern int blkdev_issue_provision(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask);
+
#define BLKDEV_ZERO_NOUNMAP (1 << 0) /* do not free blocks */
#define BLKDEV_ZERO_NOFALLBACK (1 << 1) /* don't write explicit zeroes */

@@ -1149,6 +1155,11 @@ static inline unsigned short queue_max_discard_segments(const struct request_que
return q->limits.max_discard_segments;
}

+static inline unsigned short queue_max_provision_sectors(const struct request_queue *q)
+{
+ return q->limits.max_provision_sectors;
+}
+
static inline unsigned int queue_max_segment_size(const struct request_queue *q)
{
return q->limits.max_segment_size;
@@ -1280,6 +1291,11 @@ static inline bool bdev_fua(struct block_device *bdev)
return test_bit(QUEUE_FLAG_FUA, &bdev_get_queue(bdev)->queue_flags);
}

+static inline unsigned int bdev_max_provision_sectors(struct block_device *bdev)
+{
+ return bdev_get_queue(bdev)->limits.max_provision_sectors;
+}
+
static inline enum blk_zoned_model bdev_zoned_model(struct block_device *bdev)
{
struct request_queue *q = bdev_get_queue(bdev);
--
2.31.0

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