Add dax_copy_edges() into each dax actor functions to perform COW in the case of IOMAP_COW type is set.
Signed-off-by: Shiyang Ruan <[email protected]> --- fs/dax.c | 39 +++++++++++++++++++++++++++++++++------ 1 file changed, 33 insertions(+), 6 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 450baafe2ea4..084cc21d47a4 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1098,11 +1098,12 @@ EXPORT_SYMBOL_GPL(__dax_zero_page_range); * offset/offset+length are not page aligned. */ static int dax_copy_edges(struct inode *inode, loff_t pos, loff_t length, - struct iomap *srcmap, void *daddr) + struct iomap *srcmap, void *daddr, bool pmd) { - unsigned offset = pos & (PAGE_SIZE - 1); + size_t page_size = pmd ? PMD_SIZE : PAGE_SIZE; + unsigned offset = pos & (page_size - 1); loff_t end = pos + length; - loff_t pg_end = round_up(end, PAGE_SIZE); + loff_t pg_end = round_up(end, page_size); void *saddr = 0; int ret = 0; @@ -1153,7 +1154,8 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, return iov_iter_zero(min(length, end - pos), iter); } - if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED)) + if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED && + iomap->type != IOMAP_COW)) return -EIO; /* @@ -1192,6 +1194,13 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, break; } + if (iomap->type == IOMAP_COW) { + ret = dax_copy_edges(inode, pos, length, srcmap, kaddr, + false); + if (ret) + break; + } + map_len = PFN_PHYS(map_len); kaddr += offset; map_len -= offset; @@ -1300,6 +1309,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, vm_fault_t ret = 0; void *entry; pfn_t pfn; + void *kaddr; trace_dax_pte_fault(inode, vmf, ret); /* @@ -1380,19 +1390,27 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, sync = dax_fault_is_synchronous(flags, vma, &iomap); switch (iomap.type) { + case IOMAP_COW: case IOMAP_MAPPED: if (iomap.flags & IOMAP_F_NEW) { count_vm_event(PGMAJFAULT); count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); major = VM_FAULT_MAJOR; } - error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn, NULL); + error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn, &kaddr); if (error < 0) goto error_finish_iomap; entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn, 0, write && !sync); + if (iomap.type == IOMAP_COW) { + error = dax_copy_edges(inode, pos, PAGE_SIZE, &srcmap, + kaddr, false); + if (error) + goto error_finish_iomap; + } + /* * If we are doing synchronous page fault and inode needs fsync, * we can insert PTE into page tables only after that happens. @@ -1523,6 +1541,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, loff_t pos; int error; pfn_t pfn; + void *kaddr; /* * Check whether offset isn't beyond end of file now. Caller is @@ -1602,14 +1621,22 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, sync = dax_fault_is_synchronous(iomap_flags, vma, &iomap); switch (iomap.type) { + case IOMAP_COW: case IOMAP_MAPPED: - error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn, NULL); + error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn, &kaddr); if (error < 0) goto finish_iomap; entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn, DAX_PMD, write && !sync); + if (iomap.type == IOMAP_COW) { + error = dax_copy_edges(inode, pos, PMD_SIZE, &srcmap, + kaddr, true); + if (error) + goto unlock_entry; + } + /* * If we are doing synchronous page fault and inode needs fsync, * we can insert PMD into page tables only after that happens. -- 2.17.0
