xfs: huge page fault support

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>

2 files changed, 30 insertions, 1 deletions

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index de2c2376242b..e78feb400e22 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1546,8 +1546,36 @@ xfs_filemap_fault(
         return ret;
 }
 
+STATIC int
+xfs_filemap_pmd_fault(
+        struct vm_area_struct   *vma,
+        unsigned long           addr,
+        pmd_t                   *pmd,
+        unsigned int            flags)
+{
+        struct inode            *inode = file_inode(vma->vm_file);
+        struct xfs_inode        *ip = XFS_I(inode);
+        int                     ret;
+
+        if (!IS_DAX(inode))
+                return VM_FAULT_FALLBACK;
+
+        trace_xfs_filemap_pmd_fault(ip);
+
+        sb_start_pagefault(inode->i_sb);
+        file_update_time(vma->vm_file);
+        xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
+        ret = __dax_pmd_fault(vma, addr, pmd, flags, xfs_get_blocks_direct,
+                                    xfs_end_io_dax_write);
+        xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
+        sb_end_pagefault(inode->i_sb);
+
+        return ret;
+}
+
 static const struct vm_operations_struct xfs_file_vm_ops = {
         .fault          = xfs_filemap_fault,
+        .pmd_fault      = xfs_filemap_pmd_fault,
         .map_pages      = filemap_map_pages,
         .page_mkwrite   = xfs_filemap_page_mkwrite,
 };
@@ -1560,7 +1588,7 @@ xfs_file_mmap(
         file_accessed(filp);
         vma->vm_ops = &xfs_file_vm_ops;
         if (IS_DAX(file_inode(filp)))
-                vma->vm_flags |= VM_MIXEDMAP;
+                vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
         return 0;
 }
 
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 9aeeb21bc3d0..5ed36b1e04c1 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -687,6 +687,7 @@ DEFINE_INODE_EVENT(xfs_inode_clear_eofblocks_tag);
 DEFINE_INODE_EVENT(xfs_inode_free_eofblocks_invalid);
 
 DEFINE_INODE_EVENT(xfs_filemap_fault);
+DEFINE_INODE_EVENT(xfs_filemap_pmd_fault);
 DEFINE_INODE_EVENT(xfs_filemap_page_mkwrite);
 
 DECLARE_EVENT_CLASS(xfs_iref_class,