[v3,06/10] fsdax: Add dax_iomap_cow_copy() for dax_iomap_zero
diff mbox series

Message ID 20210319015237.993880-7-ruansy.fnst@fujitsu.com
State New, archived
Headers show
Series
  • fsdax,xfs: Add reflink&dedupe support for fsdax
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Commit Message

ruansy.fnst@fujitsu.com March 19, 2021, 1:52 a.m. UTC
Punch hole on a reflinked file needs dax_copy_edge() too.  Otherwise,
data in not aligned area will be not correct.  So, add the srcmap to
dax_iomap_zero() and replace memset() as dax_copy_edge().

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 fs/dax.c               | 9 +++++++--
 fs/iomap/buffered-io.c | 2 +-
 include/linux/dax.h    | 3 ++-
 3 files changed, 10 insertions(+), 4 deletions(-)

Comments

Ritesh Harjani April 1, 2021, 6:45 a.m. UTC | #1
On 21/03/19 09:52AM, Shiyang Ruan wrote:
> Punch hole on a reflinked file needs dax_copy_edge() too.  Otherwise,
> data in not aligned area will be not correct.  So, add the srcmap to
> dax_iomap_zero() and replace memset() as dax_copy_edge().
>
> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
> ---
>  fs/dax.c               | 9 +++++++--
>  fs/iomap/buffered-io.c | 2 +-
>  include/linux/dax.h    | 3 ++-
>  3 files changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index cfe513eb111e..348297b38f76 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -1174,7 +1174,8 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
>  }
>  #endif /* CONFIG_FS_DAX_PMD */
>
> -s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap)
> +s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap,
> +		struct iomap *srcmap)

Do we know why does dax_iomap_zero() operates on PAGE_SIZE range?
IIUC, dax_zero_page_range() can take nr_pages as a parameter. But we still
always use one page at a time. Why is that?

>  {
>  	sector_t sector = iomap_sector(iomap, pos & PAGE_MASK);
>  	pgoff_t pgoff;
> @@ -1204,7 +1205,11 @@ s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap)
>  	}
>
>  	if (!page_aligned) {
> -		memset(kaddr + offset, 0, size);
> +		if (iomap->addr != srcmap->addr)
> +			dax_iomap_cow_copy(offset, size, PAGE_SIZE, srcmap,
> +					   kaddr, true);
> +		else
> +			memset(kaddr + offset, 0, size);
>  		dax_flush(iomap->dax_dev, kaddr + offset, size);
>  	}
>  	dax_read_unlock(id);
>

Maybe the above could be simplified to this?

	if (page_aligned) {
		rc = dax_zero_page_range(iomap->dax_dev, pgoff, 1);
	} else {
		rc = dax_direct_access(iomap->dax_dev, pgoff, 1, &kaddr, NULL);
		if (iomap->addr != srcmap->addr)
			dax_iomap_cow_copy(offset, size, PAGE_SIZE, srcmap,
					   kaddr, true);
		else
			memset(kaddr + offset, 0, size);
		dax_flush(iomap->dax_dev, kaddr + offset, size);
	}

	dax_read_unlock(id);
	return rc < 0 ? rc : size;

Other than that looks good.
Feel free to add.
Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com>
ruansy.fnst@fujitsu.com April 1, 2021, 7 a.m. UTC | #2
> -----Original Message-----
> From: Ritesh Harjani <ritesh.list@gmail.com>
> Sent: Thursday, April 1, 2021 2:45 PM
> Subject: Re: [PATCH v3 06/10] fsdax: Add dax_iomap_cow_copy() for
> dax_iomap_zero
> 
> On 21/03/19 09:52AM, Shiyang Ruan wrote:
> > Punch hole on a reflinked file needs dax_copy_edge() too.  Otherwise,
> > data in not aligned area will be not correct.  So, add the srcmap to
> > dax_iomap_zero() and replace memset() as dax_copy_edge().
> >
> > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
> > ---
> >  fs/dax.c               | 9 +++++++--
> >  fs/iomap/buffered-io.c | 2 +-
> >  include/linux/dax.h    | 3 ++-
> >  3 files changed, 10 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/dax.c b/fs/dax.c
> > index cfe513eb111e..348297b38f76 100644
> > --- a/fs/dax.c
> > +++ b/fs/dax.c
> > @@ -1174,7 +1174,8 @@ static vm_fault_t dax_pmd_load_hole(struct
> > xa_state *xas, struct vm_fault *vmf,  }  #endif /* CONFIG_FS_DAX_PMD
> > */
> >
> > -s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap)
> > +s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap,
> > +		struct iomap *srcmap)
> 
> Do we know why does dax_iomap_zero() operates on PAGE_SIZE range?
> IIUC, dax_zero_page_range() can take nr_pages as a parameter. But we still
> always use one page at a time. Why is that?

I think we can handle more than one page here.  The length can be more than one PAGE_SIZE.

> 
> >  {
> >  	sector_t sector = iomap_sector(iomap, pos & PAGE_MASK);
> >  	pgoff_t pgoff;
> > @@ -1204,7 +1205,11 @@ s64 dax_iomap_zero(loff_t pos, u64 length, struct
> iomap *iomap)
> >  	}
> >
> >  	if (!page_aligned) {
> > -		memset(kaddr + offset, 0, size);
> > +		if (iomap->addr != srcmap->addr)
> > +			dax_iomap_cow_copy(offset, size, PAGE_SIZE, srcmap,
> > +					   kaddr, true);
> > +		else
> > +			memset(kaddr + offset, 0, size);
> >  		dax_flush(iomap->dax_dev, kaddr + offset, size);
> >  	}
> >  	dax_read_unlock(id);
> >
> 
> Maybe the above could be simplified to this?
> 
> 	if (page_aligned) {
> 		rc = dax_zero_page_range(iomap->dax_dev, pgoff, 1);
> 	} else {
> 		rc = dax_direct_access(iomap->dax_dev, pgoff, 1, &kaddr, NULL);

This looks good.  Need add check for rc here.

> 		if (iomap->addr != srcmap->addr)
> 			dax_iomap_cow_copy(offset, size, PAGE_SIZE, srcmap,
> 					   kaddr, true);
> 		else
> 			memset(kaddr + offset, 0, size);
> 		dax_flush(iomap->dax_dev, kaddr + offset, size);
> 	}
> 
> 	dax_read_unlock(id);
> 	return rc < 0 ? rc : size;
> 
> Other than that looks good.
> Feel free to add.
> Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com>
> 

--
Thanks,
Ruan Shiyang.

Patch
diff mbox series

diff --git a/fs/dax.c b/fs/dax.c
index cfe513eb111e..348297b38f76 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1174,7 +1174,8 @@  static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
 }
 #endif /* CONFIG_FS_DAX_PMD */
 
-s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap)
+s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap,
+		struct iomap *srcmap)
 {
 	sector_t sector = iomap_sector(iomap, pos & PAGE_MASK);
 	pgoff_t pgoff;
@@ -1204,7 +1205,11 @@  s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap)
 	}
 
 	if (!page_aligned) {
-		memset(kaddr + offset, 0, size);
+		if (iomap->addr != srcmap->addr)
+			dax_iomap_cow_copy(offset, size, PAGE_SIZE, srcmap,
+					   kaddr, true);
+		else
+			memset(kaddr + offset, 0, size);
 		dax_flush(iomap->dax_dev, kaddr + offset, size);
 	}
 	dax_read_unlock(id);
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 16a1e82e3aeb..d754b1f1a05d 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -933,7 +933,7 @@  static loff_t iomap_zero_range_actor(struct inode *inode, loff_t pos,
 		s64 bytes;
 
 		if (IS_DAX(inode))
-			bytes = dax_iomap_zero(pos, length, iomap);
+			bytes = dax_iomap_zero(pos, length, iomap, srcmap);
 		else
 			bytes = iomap_zero(inode, pos, length, iomap, srcmap);
 		if (bytes < 0)
diff --git a/include/linux/dax.h b/include/linux/dax.h
index b52f084aa643..3275e01ed33d 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -237,7 +237,8 @@  vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
 				      pgoff_t index);
-s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap);
+s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap,
+		struct iomap *srcmap);
 static inline bool dax_mapping(struct address_space *mapping)
 {
 	return mapping->host && IS_DAX(mapping->host);