On Tue, May 11, 2021 at 11:09:29AM +0800, 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 <[email protected]>
> Reviewed-by: Ritesh Harjani <[email protected]>
> ---
> fs/dax.c | 25 +++++++++++++++----------
> fs/iomap/buffered-io.c | 2 +-
> include/linux/dax.h | 3 ++-
> 3 files changed, 18 insertions(+), 12 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index ef0e564e7904..ee9d28a79bfb 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -1186,7 +1186,8 @@ 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;
> @@ -1208,19 +1209,23 @@ s64 dax_iomap_zero(loff_t pos, u64 length, struct
> iomap *iomap)
>
> if (page_aligned)
> rc = dax_zero_page_range(iomap->dax_dev, pgoff, 1);
> - else
> + else {
> rc = dax_direct_access(iomap->dax_dev, pgoff, 1, &kaddr, NULL);
> - if (rc < 0) {
> - dax_read_unlock(id);
> - return rc;
> - }
> -
> - if (!page_aligned) {
> - memset(kaddr + offset, 0, size);
> + if (rc < 0)
> + goto out;
> + if (iomap->addr != srcmap->addr) {
Why isn't this "if (srcmap->type != IOMAP_HOLE)" ?
I suppose it has the same effect, since @iomap should never be a hole
and we should never have a @srcmap that's the same as @iomap, but
still, we use IOMAP_HOLE checks in most other parts of fs/iomap/.
Other than that, the logic looks decent to me.
--D
> + rc = dax_iomap_cow_copy(offset, size, PAGE_SIZE, srcmap,
> + kaddr);
> + if (rc < 0)
> + goto out;
> + } else
> + memset(kaddr + offset, 0, size);
> dax_flush(iomap->dax_dev, kaddr + offset, size);
> }
> +
> +out:
> dax_read_unlock(id);
> - return size;
> + return rc < 0 ? rc : size;
> }
>
> static loff_t
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index f2cd2034a87b..2734955ea67f 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);
> --
> 2.31.1
>
>
>
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