> + pfn_t pfn;
>
> if (write) {
> sb_start_pagefault(sb);
> @@ -287,16 +288,39 @@ static int ext4_dax_huge_fault(struct vm_fault *vmf,
> down_read(&EXT4_I(inode)->i_mmap_sem);
> handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
> EXT4_DATA_TRANS_BLOCKS(sb));
> + if (IS_ERR(handle)) {
> + up_read(&EXT4_I(inode)->i_mmap_sem);
> + sb_end_pagefault(sb);
> + return VM_FAULT_SIGBUS;
> + }
> } else {
> down_read(&EXT4_I(inode)->i_mmap_sem);
> }
> - if (!IS_ERR(handle))
> - result = dax_iomap_fault(vmf, pe_size, &ext4_iomap_ops, NULL);
> - else
> - result = VM_FAULT_SIGBUS;
> + result = dax_iomap_fault(vmf, pe_size, &ext4_iomap_ops, &pfn);
Maybe split the error handling refactor into a simple prep patch to
make this one more readable?
> + /* Write fault but PFN mapped only RO? */
> + if (result & VM_FAULT_NEEDDSYNC) {
> + int err;
> + loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT;
> + size_t len = 0;
> +
> + if (pe_size == PE_SIZE_PTE)
> + len = PAGE_SIZE;
> +#ifdef CONFIG_FS_DAX_PMD
> + else if (pe_size == PE_SIZE_PMD)
> + len = HPAGE_PMD_SIZE;
> +#endif
> + else
> + WARN_ON_ONCE(1);
> + err = vfs_fsync_range(vmf->vma->vm_file, start,
> + start + len - 1, 1);
> + if (err)
> + result = VM_FAULT_SIGBUS;
> + else
> + result = dax_insert_pfn_mkwrite(vmf, pe_size,
> + pfn);
> + }
I think this needs to become a helper exported from the DAX code,
way too much magic inside the file system as-is.
