Re: [PATCH 3/7] fsdax: Copy data before write

[Ruan Shiyang]

On 2021/2/8 下午11:14, Christoph Hellwig wrote:

        switch (iomap.type) {
        case IOMAP_MAPPED:
+cow:
                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_direct_access(&iomap, pos, PAGE_SIZE,
-                                               NULL, &pfn);
+                                               &kaddr, &pfn);

Any chance you could look into factoring out this code into a helper
to avoid the goto magic, which is a little too convoluted?

        switch (iomap.type) {
        case IOMAP_MAPPED:
+cow:
                error = dax_iomap_direct_access(&iomap, pos, PMD_SIZE,
-                                               NULL, &pfn);
+                                               &kaddr, &pfn);
                if (error < 0)
                        goto finish_iomap;

entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn,

                                                DAX_PMD, write && !sync);

+ if (srcmap.type != IOMAP_HOLE) {

Same here.

Thanks for suggestion.  I'll try it.


--
Thanks,
Ruan Shiyang.