On Wed 23-08-17 11:37:14, Christoph Hellwig wrote:
> > + 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?
OK, will do.
> > + /* 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.
Good point, there isn't anything fs specific in there.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
