On Sun, Aug 29, 2021 at 08:25:16PM +0800, Shiyang Ruan wrote:
> In fsdax mode, WRITE and ZERO on a shared extent need CoW performed.
> After that, new allocated extents needs to be remapped to the file. Add
> an implementation of ->iomap_end() for dax write ops to do the remapping
> work.
Please split the new dax infrastructure from the XFS changes.
> static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
> - int *iomap_errp, const struct iomap_ops *ops)
> + int *iomap_errp, const struct iomap_ops *ops)
> {
> struct address_space *mapping = vmf->vma->vm_file->f_mapping;
> XA_STATE(xas, &mapping->i_pages, vmf->pgoff);
> @@ -1631,7 +1664,7 @@ static bool dax_fault_check_fallback(struct vm_fault *vmf, struct xa_state *xas,
> }
>
> static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
> - const struct iomap_ops *ops)
> + const struct iomap_ops *ops)
These looks like unrelated whitespace changes.
> -static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
> +loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
> {
> const struct iomap *iomap = &iter->iomap;
> const struct iomap *srcmap = iomap_iter_srcmap(iter);
> @@ -918,6 +918,7 @@ static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
>
> return written;
> }
> +EXPORT_SYMBOL_GPL(iomap_zero_iter);
I don't see why this would have to be exported.
> + unsigned flags,
> + struct iomap *iomap)
> +{
> + int error = 0;
> + struct xfs_inode *ip = XFS_I(inode);
> + bool cow = xfs_is_cow_inode(ip);
The cow variable is only used once, so I think we can drop it.
> + const struct iomap_iter *iter =
> + container_of(iomap, typeof(*iter), iomap);
Please comment this as it is a little unusual.
> +
> + if (cow) {
> + if (iter->processed <= 0)
> + xfs_reflink_cancel_cow_range(ip, pos, length, true);
> + else
> + error = xfs_reflink_end_cow(ip, pos, iter->processed);
> + }
> + return error ?: iter->processed;
The ->iomap_end convention is to return 0 or a negative error code.
Also i'd much prefer to just spell this out in a normal sequential way:
if (!xfs_is_cow_inode(ip))
return 0;
if (iter->processed <= 0) {
xfs_reflink_cancel_cow_range(ip, pos, length, true);
return 0;
}
return xfs_reflink_end_cow(ip, pos, iter->processed);
> +static inline int
> +xfs_iomap_zero_range(
> + struct xfs_inode *ip,
> + loff_t pos,
> + loff_t len,
> + bool *did_zero)
> +{
> + struct inode *inode = VFS_I(ip);
> +
> + return IS_DAX(inode)
> + ? dax_iomap_zero_range(inode, pos, len, did_zero,
> + &xfs_dax_write_iomap_ops)
> + : iomap_zero_range(inode, pos, len, did_zero,
> + &xfs_buffered_write_iomap_ops);
> +}
if (IS_DAX(inode))
return dax_iomap_zero_range(inode, pos, len, did_zero,
&xfs_dax_write_iomap_ops);
return iomap_zero_range(inode, pos, len, did_zero,
&xfs_buffered_write_iomap_ops);
> +static inline int
> +xfs_iomap_truncate_page(
> + struct xfs_inode *ip,
> + loff_t pos,
> + bool *did_zero)
> +{
> + struct inode *inode = VFS_I(ip);
> +
> + return IS_DAX(inode)
> + ? dax_iomap_truncate_page(inode, pos, did_zero,
> + &xfs_dax_write_iomap_ops)
> + : iomap_truncate_page(inode, pos, did_zero,
> + &xfs_buffered_write_iomap_ops);
> +}
Same here.
