On 8:45 17/04, Darrick J. Wong wrote:
> 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?
Clearly my testing was not good enough. This should be -
memcpy(kaddr, iomap->inline_data, offset);
We copy the part which is not zeroed to new location.
>
> > 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?
Ahh.. I will fix this.
>
> --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
> >
>
--
Goldwyn
