ext4: huge page fault support

Orabug: 22913653

Use DAX to provide support for huge pages.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 11bd1a9ecdd687b8a4b9b360b7e4b74a1a5e2bd5)
Signed-off-by: Dan Duval <dan.duval@oracle.com>

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 122b7efcefd5c04e10cc6f097f97da2c885b737e..42fefd1ff57865f7d5c9fddd5a9191f182968aee 100644 (file)
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -211,6 +211,13 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
                                        /* Is this the right get_block? */
 }
 
+static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
+                                               pmd_t *pmd, unsigned int flags)
+{
+       return dax_pmd_fault(vma, addr, pmd, flags, ext4_get_block_write,
+                               ext4_end_io_unwritten);
+}
+
 static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
        return dax_mkwrite(vma, vmf, ext4_get_block, ext4_end_io_unwritten);
@@ -218,6 +225,7 @@ static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 
 static const struct vm_operations_struct ext4_dax_vm_ops = {
        .fault          = ext4_dax_fault,
+       .pmd_fault      = ext4_dax_pmd_fault,
        .page_mkwrite   = ext4_dax_mkwrite,
        .pfn_mkwrite    = dax_pfn_mkwrite,
 };
@@ -243,7 +251,7 @@ static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
        file_accessed(file);
        if (IS_DAX(file_inode(file))) {
                vma->vm_ops = &ext4_dax_vm_ops;
-               vma->vm_flags |= VM_MIXEDMAP;
+               vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
        } else {
                vma->vm_ops = &ext4_file_vm_ops;
        }