Messages in this thread | | | Date | Thu, 2 Sep 2021 09:43:08 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH v8 6/7] xfs: support CoW in fsdax mode |
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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.
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