diff mbox series

[v7,5/5] loop: Add support for provision requests

Message ID 20230522221000.603769-1-sarthakkukreti@chromium.org (mailing list archive)
State Not Applicable, archived
Delegated to: Mike Snitzer
Headers show
Series None | expand

Commit Message

Sarthak Kukreti May 22, 2023, 10:09 p.m. UTC 
On Mon, May 22, 2023 at 9:37 AM Darrick J. Wong <djwong@kernel.org> wrote:
>
> If someone calls fallocate(UNSHARE_RANGE) on a loop bdev, shouldn't
> there be a way to pass that through to the fallocate call to the backing
> file?
>
> --D
>

Yeah, I think we could add a REQ_UNSHARE bit (similar to REQ_NOUNMAP) to pass down the intent to the backing file (and possibly beyond...).

I took a stab at implementing it as a follow up patch so that there's less review churn on the current series. If it looks good, I can add it to the end of the series (or incorporate this into the existing block and loop patches):

From: Sarthak Kukreti <sarthakkukreti@chromium.org>
Date: Mon, 22 May 2023 14:18:15 -0700
Subject: [PATCH] block: Pass unshare intent via REQ_OP_PROVISION

Allow REQ_OP_PROVISION to pass in an extra REQ_UNSHARE bit to
annotate unshare requests to underlying layers. Layers that support
FALLOC_FL_UNSHARE will be able to use this as an indicator of which
fallocate() mode to use.

Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
---
 block/blk-lib.c           |  6 +++++-
 block/fops.c              |  6 +++++-
 drivers/block/loop.c      | 35 +++++++++++++++++++++++++++++------
 include/linux/blk_types.h |  3 +++
 include/linux/blkdev.h    |  3 ++-
 5 files changed, 44 insertions(+), 9 deletions(-)

Comments

Darrick J. Wong May 23, 2023, 1:22 a.m. UTC | #1 
On Mon, May 22, 2023 at 03:09:55PM -0700, Sarthak Kukreti wrote:
> On Mon, May 22, 2023 at 9:37 AM Darrick J. Wong <djwong@kernel.org> wrote:
> >
> > If someone calls fallocate(UNSHARE_RANGE) on a loop bdev, shouldn't
> > there be a way to pass that through to the fallocate call to the backing
> > file?
> >
> > --D
> >
> 
> Yeah, I think we could add a REQ_UNSHARE bit (similar to REQ_NOUNMAP) to pass down the intent to the backing file (and possibly beyond...).
> 
> I took a stab at implementing it as a follow up patch so that there's
> less review churn on the current series. If it looks good, I can add
> it to the end of the series (or incorporate this into the existing
> block and loop patches):

It looks like a reasonable addition to the end of the series, assuming
that filling holes in thinp devices is cheap but unsharing snapshot
blocks is not.

> From: Sarthak Kukreti <sarthakkukreti@chromium.org>
> Date: Mon, 22 May 2023 14:18:15 -0700
> Subject: [PATCH] block: Pass unshare intent via REQ_OP_PROVISION
> 
> Allow REQ_OP_PROVISION to pass in an extra REQ_UNSHARE bit to
> annotate unshare requests to underlying layers. Layers that support
> FALLOC_FL_UNSHARE will be able to use this as an indicator of which
> fallocate() mode to use.

> Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
> ---
>  block/blk-lib.c           |  6 +++++-
>  block/fops.c              |  6 +++++-
>  drivers/block/loop.c      | 35 +++++++++++++++++++++++++++++------
>  include/linux/blk_types.h |  3 +++
>  include/linux/blkdev.h    |  3 ++-
>  5 files changed, 44 insertions(+), 9 deletions(-)
> 
> diff --git a/block/blk-lib.c b/block/blk-lib.c
> index 3cff5fb654f5..bea6f5a700b3 100644
> --- a/block/blk-lib.c
> +++ b/block/blk-lib.c
> @@ -350,6 +350,7 @@ EXPORT_SYMBOL(blkdev_issue_secure_erase);
>   * @sector:	start sector
>   * @nr_sects:	number of sectors to provision
>   * @gfp_mask:	memory allocation flags (for bio_alloc)
> + * @flags:	controls detailed behavior
>   *
>   * Description:
>   *  Issues a provision request to the block device for the range of sectors.
> @@ -357,7 +358,7 @@ EXPORT_SYMBOL(blkdev_issue_secure_erase);
>   *  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 nr_sects, gfp_t gfp, unsigned flags)
>  {
>  	sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
>  	unsigned int max_sectors = bdev_max_provision_sectors(bdev);
> @@ -380,6 +381,9 @@ int blkdev_issue_provision(struct block_device *bdev, sector_t sector,
>  		bio->bi_iter.bi_sector = sector;
>  		bio->bi_iter.bi_size = req_sects << SECTOR_SHIFT;
>  
> +		if (flags & BLKDEV_UNSHARE_RANGE)

This is a provisioning flag, shouldn't this be ...
BLKDEV_PROVISION_UNSHARE or something?

> +			bio->bi_opf |= REQ_UNSHARE;
> +
>  		sector += req_sects;
>  		nr_sects -= req_sects;
>  		if (!nr_sects) {
> diff --git a/block/fops.c b/block/fops.c
> index be2e41f160bf..6848756f0557 100644
> --- a/block/fops.c
> +++ b/block/fops.c
> @@ -659,7 +659,11 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
>  	case FALLOC_FL_KEEP_SIZE:
>  	case FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE:
>  		error = blkdev_issue_provision(bdev, start >> SECTOR_SHIFT,
> -					       len >> SECTOR_SHIFT, GFP_KERNEL);
> +					       len >> SECTOR_SHIFT, GFP_KERNEL,
> +					       (mode &
> +						FALLOC_FL_UNSHARE_RANGE) ?
> +						       BLKDEV_UNSHARE_RANGE :
> +						       0);

You might want to do something about the six level indent here;
Linus hates that.

--D

>  		break;
>  	case FALLOC_FL_ZERO_RANGE:
>  	case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index 7fe1a6629754..c844b145d666 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -306,6 +306,30 @@ static int lo_read_simple(struct loop_device *lo, struct request *rq,
>  	return 0;
>  }
>  
> +static bool validate_fallocate_mode(struct loop_device *lo, int mode)
> +{
> +	bool ret = true;
> +
> +	switch (mode) {
> +	case FALLOC_FL_PUNCH_HOLE:
> +	case FALLOC_FL_ZERO_RANGE:
> +		if (!bdev_max_discard_sectors(lo->lo_device))
> +			ret = false;
> +		break;
> +	case 0:
> +	case FALLOC_FL_UNSHARE_RANGE:
> +		if (!bdev_max_provision_sectors(lo->lo_device))
> +			ret = false;
> +		break;
> +
> +	default:
> +		ret = false;
> +	}
> +
> +	return ret;
> +}
> +
> +
>  static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos,
>  			int mode)
>  {
> @@ -316,11 +340,7 @@ static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos,
>  	struct file *file = lo->lo_backing_file;
>  	int ret;
>  
> -	if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE) &&
> -	    !bdev_max_discard_sectors(lo->lo_device))
> -		return -EOPNOTSUPP;
> -
> -	if (mode == 0 && !bdev_max_provision_sectors(lo->lo_device))
> +	if (!validate_fallocate_mode(lo, mode))
>  		return -EOPNOTSUPP;
>  
>  	mode |= FALLOC_FL_KEEP_SIZE;
> @@ -493,7 +513,10 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq)
>  	case REQ_OP_DISCARD:
>  		return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE);
>  	case REQ_OP_PROVISION:
> -		return lo_fallocate(lo, rq, pos, 0);
> +		return lo_fallocate(lo, rq, pos,
> +				    (rq->cmd_flags & REQ_UNSHARE) ?
> +					    FALLOC_FL_UNSHARE_RANGE :
> +					    0);
>  	case REQ_OP_WRITE:
>  		if (cmd->use_aio)
>  			return lo_rw_aio(lo, cmd, pos, ITER_SOURCE);
> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> index b7bb0226fdee..1a536fd897cb 100644
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -423,6 +423,8 @@ enum req_flag_bits {
>  	 */
>  	/* for REQ_OP_WRITE_ZEROES: */
>  	__REQ_NOUNMAP,		/* do not free blocks when zeroing */
> +	/* for REQ_OP_PROVISION: */
> +	__REQ_UNSHARE,		/* unshare blocks */
>  
>  	__REQ_NR_BITS,		/* stops here */
>  };
> @@ -451,6 +453,7 @@ enum req_flag_bits {
>  #define REQ_FS_PRIVATE	(__force blk_opf_t)(1ULL << __REQ_FS_PRIVATE)
>  
>  #define REQ_NOUNMAP	(__force blk_opf_t)(1ULL << __REQ_NOUNMAP)
> +#define REQ_UNSHARE	(__force blk_opf_t)(1ULL << __REQ_UNSHARE)
>  
>  #define REQ_FAILFAST_MASK \
>  	(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 462ce586d46f..60c09b0d3fc9 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1049,10 +1049,11 @@ 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);
> +		sector_t nr_sects, gfp_t gfp_mask, unsigned int flags);
>  
>  #define BLKDEV_ZERO_NOUNMAP	(1 << 0)  /* do not free blocks */
>  #define BLKDEV_ZERO_NOFALLBACK	(1 << 1)  /* don't write explicit zeroes */
> +#define BLKDEV_UNSHARE_RANGE	(1 << 2)  /* unshare range on provision */
>  
>  extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
>  		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
> -- 
> 2.39.2
> 

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Sarthak Kukreti Oct. 7, 2023, 1:29 a.m. UTC | #2 
On Mon, May 22, 2023 at 6:22 PM Darrick J. Wong <djwong@kernel.org> wrote:
>
> On Mon, May 22, 2023 at 03:09:55PM -0700, Sarthak Kukreti wrote:
> > On Mon, May 22, 2023 at 9:37 AM Darrick J. Wong <djwong@kernel.org> wrote:
> > >
> > > If someone calls fallocate(UNSHARE_RANGE) on a loop bdev, shouldn't
> > > there be a way to pass that through to the fallocate call to the backing
> > > file?
> > >
> > > --D
> > >
> >
> > Yeah, I think we could add a REQ_UNSHARE bit (similar to REQ_NOUNMAP) to pass down the intent to the backing file (and possibly beyond...).
> >
> > I took a stab at implementing it as a follow up patch so that there's
> > less review churn on the current series. If it looks good, I can add
> > it to the end of the series (or incorporate this into the existing
> > block and loop patches):
>
> It looks like a reasonable addition to the end of the series, assuming
> that filling holes in thinp devices is cheap but unsharing snapshot
> blocks is not.
>
> > From: Sarthak Kukreti <sarthakkukreti@chromium.org>
> > Date: Mon, 22 May 2023 14:18:15 -0700
> > Subject: [PATCH] block: Pass unshare intent via REQ_OP_PROVISION
> >
> > Allow REQ_OP_PROVISION to pass in an extra REQ_UNSHARE bit to
> > annotate unshare requests to underlying layers. Layers that support
> > FALLOC_FL_UNSHARE will be able to use this as an indicator of which
> > fallocate() mode to use.
>
> > Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
> > ---
> >  block/blk-lib.c           |  6 +++++-
> >  block/fops.c              |  6 +++++-
> >  drivers/block/loop.c      | 35 +++++++++++++++++++++++++++++------
> >  include/linux/blk_types.h |  3 +++
> >  include/linux/blkdev.h    |  3 ++-
> >  5 files changed, 44 insertions(+), 9 deletions(-)
> >
> > diff --git a/block/blk-lib.c b/block/blk-lib.c
> > index 3cff5fb654f5..bea6f5a700b3 100644
> > --- a/block/blk-lib.c
> > +++ b/block/blk-lib.c
> > @@ -350,6 +350,7 @@ EXPORT_SYMBOL(blkdev_issue_secure_erase);
> >   * @sector:  start sector
> >   * @nr_sects:        number of sectors to provision
> >   * @gfp_mask:        memory allocation flags (for bio_alloc)
> > + * @flags:   controls detailed behavior
> >   *
> >   * Description:
> >   *  Issues a provision request to the block device for the range of sectors.
> > @@ -357,7 +358,7 @@ EXPORT_SYMBOL(blkdev_issue_secure_erase);
> >   *  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 nr_sects, gfp_t gfp, unsigned flags)
> >  {
> >       sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
> >       unsigned int max_sectors = bdev_max_provision_sectors(bdev);
> > @@ -380,6 +381,9 @@ int blkdev_issue_provision(struct block_device *bdev, sector_t sector,
> >               bio->bi_iter.bi_sector = sector;
> >               bio->bi_iter.bi_size = req_sects << SECTOR_SHIFT;
> >
> > +             if (flags & BLKDEV_UNSHARE_RANGE)
>
> This is a provisioning flag, shouldn't this be ...
> BLKDEV_PROVISION_UNSHARE or something?
>
Done in v8, thanks!

> > +                     bio->bi_opf |= REQ_UNSHARE;
> > +
> >               sector += req_sects;
> >               nr_sects -= req_sects;
> >               if (!nr_sects) {
> > diff --git a/block/fops.c b/block/fops.c
> > index be2e41f160bf..6848756f0557 100644
> > --- a/block/fops.c
> > +++ b/block/fops.c
> > @@ -659,7 +659,11 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
> >       case FALLOC_FL_KEEP_SIZE:
> >       case FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE:
> >               error = blkdev_issue_provision(bdev, start >> SECTOR_SHIFT,
> > -                                            len >> SECTOR_SHIFT, GFP_KERNEL);
> > +                                            len >> SECTOR_SHIFT, GFP_KERNEL,
> > +                                            (mode &
> > +                                             FALLOC_FL_UNSHARE_RANGE) ?
> > +                                                    BLKDEV_UNSHARE_RANGE :
> > +                                                    0);
>
> You might want to do something about the six level indent here;
> Linus hates that.
>
Thanks for pointing it out, I switched it up a bit in v8 but it still
looks a bit weird to me.

Best
Sarthak

> --D
>
> >               break;
> >       case FALLOC_FL_ZERO_RANGE:
> >       case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
> > diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> > index 7fe1a6629754..c844b145d666 100644
> > --- a/drivers/block/loop.c
> > +++ b/drivers/block/loop.c
> > @@ -306,6 +306,30 @@ static int lo_read_simple(struct loop_device *lo, struct request *rq,
> >       return 0;
> >  }
> >
> > +static bool validate_fallocate_mode(struct loop_device *lo, int mode)
> > +{
> > +     bool ret = true;
> > +
> > +     switch (mode) {
> > +     case FALLOC_FL_PUNCH_HOLE:
> > +     case FALLOC_FL_ZERO_RANGE:
> > +             if (!bdev_max_discard_sectors(lo->lo_device))
> > +                     ret = false;
> > +             break;
> > +     case 0:
> > +     case FALLOC_FL_UNSHARE_RANGE:
> > +             if (!bdev_max_provision_sectors(lo->lo_device))
> > +                     ret = false;
> > +             break;
> > +
> > +     default:
> > +             ret = false;
> > +     }
> > +
> > +     return ret;
> > +}
> > +
> > +
> >  static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos,
> >                       int mode)
> >  {
> > @@ -316,11 +340,7 @@ static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos,
> >       struct file *file = lo->lo_backing_file;
> >       int ret;
> >
> > -     if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE) &&
> > -         !bdev_max_discard_sectors(lo->lo_device))
> > -             return -EOPNOTSUPP;
> > -
> > -     if (mode == 0 && !bdev_max_provision_sectors(lo->lo_device))
> > +     if (!validate_fallocate_mode(lo, mode))
> >               return -EOPNOTSUPP;
> >
> >       mode |= FALLOC_FL_KEEP_SIZE;
> > @@ -493,7 +513,10 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq)
> >       case REQ_OP_DISCARD:
> >               return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE);
> >       case REQ_OP_PROVISION:
> > -             return lo_fallocate(lo, rq, pos, 0);
> > +             return lo_fallocate(lo, rq, pos,
> > +                                 (rq->cmd_flags & REQ_UNSHARE) ?
> > +                                         FALLOC_FL_UNSHARE_RANGE :
> > +                                         0);
> >       case REQ_OP_WRITE:
> >               if (cmd->use_aio)
> >                       return lo_rw_aio(lo, cmd, pos, ITER_SOURCE);
> > diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> > index b7bb0226fdee..1a536fd897cb 100644
> > --- a/include/linux/blk_types.h
> > +++ b/include/linux/blk_types.h
> > @@ -423,6 +423,8 @@ enum req_flag_bits {
> >        */
> >       /* for REQ_OP_WRITE_ZEROES: */
> >       __REQ_NOUNMAP,          /* do not free blocks when zeroing */
> > +     /* for REQ_OP_PROVISION: */
> > +     __REQ_UNSHARE,          /* unshare blocks */
> >
> >       __REQ_NR_BITS,          /* stops here */
> >  };
> > @@ -451,6 +453,7 @@ enum req_flag_bits {
> >  #define REQ_FS_PRIVATE       (__force blk_opf_t)(1ULL << __REQ_FS_PRIVATE)
> >
> >  #define REQ_NOUNMAP  (__force blk_opf_t)(1ULL << __REQ_NOUNMAP)
> > +#define REQ_UNSHARE  (__force blk_opf_t)(1ULL << __REQ_UNSHARE)
> >
> >  #define REQ_FAILFAST_MASK \
> >       (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
> > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> > index 462ce586d46f..60c09b0d3fc9 100644
> > --- a/include/linux/blkdev.h
> > +++ b/include/linux/blkdev.h
> > @@ -1049,10 +1049,11 @@ 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);
> > +             sector_t nr_sects, gfp_t gfp_mask, unsigned int flags);
> >
> >  #define BLKDEV_ZERO_NOUNMAP  (1 << 0)  /* do not free blocks */
> >  #define BLKDEV_ZERO_NOFALLBACK       (1 << 1)  /* don't write explicit zeroes */
> > +#define BLKDEV_UNSHARE_RANGE (1 << 2)  /* unshare range on provision */
> >
> >  extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
> >               sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
> > --
> > 2.39.2
> >

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diff mbox series

Patch

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 3cff5fb654f5..bea6f5a700b3 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -350,6 +350,7 @@  EXPORT_SYMBOL(blkdev_issue_secure_erase);
  * @sector:	start sector
  * @nr_sects:	number of sectors to provision
  * @gfp_mask:	memory allocation flags (for bio_alloc)
+ * @flags:	controls detailed behavior
  *
  * Description:
  *  Issues a provision request to the block device for the range of sectors.
@@ -357,7 +358,7 @@  EXPORT_SYMBOL(blkdev_issue_secure_erase);
  *  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 nr_sects, gfp_t gfp, unsigned flags)
 {
 	sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
 	unsigned int max_sectors = bdev_max_provision_sectors(bdev);
@@ -380,6 +381,9 @@  int blkdev_issue_provision(struct block_device *bdev, sector_t sector,
 		bio->bi_iter.bi_sector = sector;
 		bio->bi_iter.bi_size = req_sects << SECTOR_SHIFT;
 
+		if (flags & BLKDEV_UNSHARE_RANGE)
+			bio->bi_opf |= REQ_UNSHARE;
+
 		sector += req_sects;
 		nr_sects -= req_sects;
 		if (!nr_sects) {
diff --git a/block/fops.c b/block/fops.c
index be2e41f160bf..6848756f0557 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -659,7 +659,11 @@  static long blkdev_fallocate(struct file *file, int mode, loff_t start,
 	case FALLOC_FL_KEEP_SIZE:
 	case FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE:
 		error = blkdev_issue_provision(bdev, start >> SECTOR_SHIFT,
-					       len >> SECTOR_SHIFT, GFP_KERNEL);
+					       len >> SECTOR_SHIFT, GFP_KERNEL,
+					       (mode &
+						FALLOC_FL_UNSHARE_RANGE) ?
+						       BLKDEV_UNSHARE_RANGE :
+						       0);
 		break;
 	case FALLOC_FL_ZERO_RANGE:
 	case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 7fe1a6629754..c844b145d666 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -306,6 +306,30 @@  static int lo_read_simple(struct loop_device *lo, struct request *rq,
 	return 0;
 }
 
+static bool validate_fallocate_mode(struct loop_device *lo, int mode)
+{
+	bool ret = true;
+
+	switch (mode) {
+	case FALLOC_FL_PUNCH_HOLE:
+	case FALLOC_FL_ZERO_RANGE:
+		if (!bdev_max_discard_sectors(lo->lo_device))
+			ret = false;
+		break;
+	case 0:
+	case FALLOC_FL_UNSHARE_RANGE:
+		if (!bdev_max_provision_sectors(lo->lo_device))
+			ret = false;
+		break;
+
+	default:
+		ret = false;
+	}
+
+	return ret;
+}
+
+
 static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos,
 			int mode)
 {
@@ -316,11 +340,7 @@  static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos,
 	struct file *file = lo->lo_backing_file;
 	int ret;
 
-	if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE) &&
-	    !bdev_max_discard_sectors(lo->lo_device))
-		return -EOPNOTSUPP;
-
-	if (mode == 0 && !bdev_max_provision_sectors(lo->lo_device))
+	if (!validate_fallocate_mode(lo, mode))
 		return -EOPNOTSUPP;
 
 	mode |= FALLOC_FL_KEEP_SIZE;
@@ -493,7 +513,10 @@  static int do_req_filebacked(struct loop_device *lo, struct request *rq)
 	case REQ_OP_DISCARD:
 		return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE);
 	case REQ_OP_PROVISION:
-		return lo_fallocate(lo, rq, pos, 0);
+		return lo_fallocate(lo, rq, pos,
+				    (rq->cmd_flags & REQ_UNSHARE) ?
+					    FALLOC_FL_UNSHARE_RANGE :
+					    0);
 	case REQ_OP_WRITE:
 		if (cmd->use_aio)
 			return lo_rw_aio(lo, cmd, pos, ITER_SOURCE);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index b7bb0226fdee..1a536fd897cb 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -423,6 +423,8 @@  enum req_flag_bits {
 	 */
 	/* for REQ_OP_WRITE_ZEROES: */
 	__REQ_NOUNMAP,		/* do not free blocks when zeroing */
+	/* for REQ_OP_PROVISION: */
+	__REQ_UNSHARE,		/* unshare blocks */
 
 	__REQ_NR_BITS,		/* stops here */
 };
@@ -451,6 +453,7 @@  enum req_flag_bits {
 #define REQ_FS_PRIVATE	(__force blk_opf_t)(1ULL << __REQ_FS_PRIVATE)
 
 #define REQ_NOUNMAP	(__force blk_opf_t)(1ULL << __REQ_NOUNMAP)
+#define REQ_UNSHARE	(__force blk_opf_t)(1ULL << __REQ_UNSHARE)
 
 #define REQ_FAILFAST_MASK \
 	(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 462ce586d46f..60c09b0d3fc9 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1049,10 +1049,11 @@  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);
+		sector_t nr_sects, gfp_t gfp_mask, unsigned int flags);
 
 #define BLKDEV_ZERO_NOUNMAP	(1 << 0)  /* do not free blocks */
 #define BLKDEV_ZERO_NOFALLBACK	(1 << 1)  /* don't write explicit zeroes */
+#define BLKDEV_UNSHARE_RANGE	(1 << 2)  /* unshare range on provision */
 
 extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,