On Tue, Apr 16, 2019 at 11:41:50AM -0500, Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
>
> However, this needed more iomap fields, so it was easier
> to pass iomap and compute inside the function rather
> than passing a log of arguments.
>
> Note, there is subtle difference between iomap_sector and
> dax_iomap_sector(). Can we replace dax_iomap_sector with
> iomap_sector()? It would need pos & PAGE_MASK though or else
> bdev_dax_pgoff() return -EINVAL.
>
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
> ---
> fs/dax.c | 14 ++++++++++----
> fs/iomap.c | 9 +--------
> include/linux/dax.h | 11 +++++------
> include/linux/iomap.h | 6 ++++++
> 4 files changed, 22 insertions(+), 18 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index abbe4a79f219..af94909640ea 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -1055,11 +1055,15 @@ static bool dax_range_is_aligned(struct block_device *bdev,
> return true;
> }
>
> -int __dax_zero_page_range(struct block_device *bdev,
> - struct dax_device *dax_dev, sector_t sector,
> - unsigned int offset, unsigned int size)
> +int __dax_zero_page_range(struct iomap *iomap, loff_t pos,
> + unsigned int offset, unsigned int size)
> {
> - if (dax_range_is_aligned(bdev, offset, size)) {
> + sector_t sector = dax_iomap_sector(iomap, pos & PAGE_MASK);
> + struct block_device *bdev = iomap->bdev;
> + struct dax_device *dax_dev = iomap->dax_dev;
> +
> + if (!(iomap->type == IOMAP_DAX_COW) &&
> + dax_range_is_aligned(bdev, offset, size)) {
> sector_t start_sector = sector + (offset >> 9);
>
> return blkdev_issue_zeroout(bdev, start_sector,
> @@ -1079,6 +1083,8 @@ int __dax_zero_page_range(struct block_device *bdev,
> dax_read_unlock(id);
> return rc;
> }
> + if (iomap->type == IOMAP_DAX_COW)
> + memcpy(iomap->inline_data, kaddr, offset);
I'm confused, why are we copying into the source page before zeroing
some part of the dax device?
> memset(kaddr + offset, 0, size);
> dax_flush(dax_dev, kaddr + offset, size);
> dax_read_unlock(id);
> diff --git a/fs/iomap.c b/fs/iomap.c
> index abdd18e404f8..90698c854883 100644
> --- a/fs/iomap.c
> +++ b/fs/iomap.c
> @@ -98,12 +98,6 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
> return written ? written : ret;
> }
>
> -static sector_t
> -iomap_sector(struct iomap *iomap, loff_t pos)
> -{
> - return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
> -}
> -
> static struct iomap_page *
> iomap_page_create(struct inode *inode, struct page *page)
> {
> @@ -990,8 +984,7 @@ static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset,
> static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes,
> struct iomap *iomap)
> {
> - return __dax_zero_page_range(iomap->bdev, iomap->dax_dev,
> - iomap_sector(iomap, pos & PAGE_MASK), offset, bytes);
> + return __dax_zero_page_range(iomap, pos, offset, bytes);
> }
>
> static loff_t
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index a11bc7b1f526..892c478d7073 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -9,6 +9,7 @@
>
> typedef unsigned long dax_entry_t;
>
> +struct iomap;
> struct iomap_ops;
> struct dax_device;
> struct dax_operations {
> @@ -161,13 +162,11 @@ int dax_file_range_compare(struct inode *src, loff_t srcoff, struct inode *dest,
> loff_t destoff, loff_t len, bool *is_same, const struct iomap_ops *ops);
>
> #ifdef CONFIG_FS_DAX
> -int __dax_zero_page_range(struct block_device *bdev,
> - struct dax_device *dax_dev, sector_t sector,
> - unsigned int offset, unsigned int length);
> +int __dax_zero_page_range(struct iomap *iomap, loff_t pos,
> + unsigned int offset, unsigned int size);
> #else
> -static inline int __dax_zero_page_range(struct block_device *bdev,
> - struct dax_device *dax_dev, sector_t sector,
> - unsigned int offset, unsigned int length)
> +static inline int __dax_zero_page_range(struct iomap *iomap, loff_t pos,
> + unsigned int offset, unsigned int size)
> {
> return -ENXIO;
> }
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index 6e885c5a38a3..3a803566dea1 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -7,6 +7,7 @@
> #include <linux/mm.h>
> #include <linux/types.h>
> #include <linux/mm_types.h>
> +#include <linux/blkdev.h>
>
> struct address_space;
> struct fiemap_extent_info;
> @@ -120,6 +121,11 @@ static inline struct iomap_page *to_iomap_page(struct page *page)
> return NULL;
> }
>
> +static inline sector_t iomap_sector(struct iomap *iomap, loff_t pos)
> +{
> + return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
Why the double indent?
--D
> +}
> +
> ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
> const struct iomap_ops *ops);
> int iomap_readpage(struct page *page, const struct iomap_ops *ops);
> --
> 2.16.4
>
