1 files changed, 69 insertions, 49 deletions

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 0b4e79fd8d05..a629dce4903e 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -284,7 +284,7 @@ xfs_file_read_iter(
 	if (file->f_mode & FMODE_NOCMTIME)
 		ioflags |= XFS_IO_INVIS;
 
-	if (unlikely(ioflags & XFS_IO_ISDIRECT)) {
+	if ((ioflags & XFS_IO_ISDIRECT) && !IS_DAX(inode)) {
 		xfs_buftarg_t	*target =
 			XFS_IS_REALTIME_INODE(ip) ?
 				mp->m_rtdev_targp : mp->m_ddev_targp;
@@ -378,7 +378,11 @@ xfs_file_splice_read(
 
 	trace_xfs_file_splice_read(ip, count, *ppos, ioflags);
 
-	ret = generic_file_splice_read(infilp, ppos, pipe, count, flags);
+	/* for dax, we need to avoid the page cache */
+	if (IS_DAX(VFS_I(ip)))
+		ret = default_file_splice_read(infilp, ppos, pipe, count, flags);
+	else
+		ret = generic_file_splice_read(infilp, ppos, pipe, count, flags);
 	if (ret > 0)
 		XFS_STATS_ADD(xs_read_bytes, ret);
 
@@ -672,7 +676,7 @@ xfs_file_dio_aio_write(
 					mp->m_rtdev_targp : mp->m_ddev_targp;
 
 	/* DIO must be aligned to device logical sector size */
-	if ((pos | count) & target->bt_logical_sectormask)
+	if (!IS_DAX(inode) && ((pos | count) & target->bt_logical_sectormask))
 		return -EINVAL;
 
 	/* "unaligned" here means not aligned to a filesystem block */
@@ -758,8 +762,11 @@ xfs_file_dio_aio_write(
 out:
 	xfs_rw_iunlock(ip, iolock);
 
-	/* No fallback to buffered IO on errors for XFS. */
-	ASSERT(ret < 0 || ret == count);
+	/*
+	 * No fallback to buffered IO on errors for XFS. DAX can result in
+	 * partial writes, but direct IO will either complete fully or fail.
+	 */
+	ASSERT(ret < 0 || ret == count || IS_DAX(VFS_I(ip)));
 	return ret;
 }
 
@@ -842,7 +849,7 @@ xfs_file_write_iter(
 	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 		return -EIO;
 
-	if (unlikely(iocb->ki_flags & IOCB_DIRECT))
+	if ((iocb->ki_flags & IOCB_DIRECT) || IS_DAX(inode))
 		ret = xfs_file_dio_aio_write(iocb, from);
 	else
 		ret = xfs_file_buffered_aio_write(iocb, from);
@@ -1063,17 +1070,6 @@ xfs_file_readdir(
 	return xfs_readdir(ip, ctx, bufsize);
 }
 
-STATIC int
-xfs_file_mmap(
-	struct file	*filp,
-	struct vm_area_struct *vma)
-{
-	vma->vm_ops = &xfs_file_vm_ops;
-
-	file_accessed(filp);
-	return 0;
-}
-
 /*
  * This type is designed to indicate the type of offset we would like
  * to search from page cache for xfs_seek_hole_data().
@@ -1454,26 +1450,11 @@ xfs_file_llseek(
  * ordering of:
  *
  * mmap_sem (MM)
- *   i_mmap_lock (XFS - truncate serialisation)
- *     page_lock (MM)
- *       i_lock (XFS - extent map serialisation)
+ *   sb_start_pagefault(vfs, freeze)
+ *     i_mmap_lock (XFS - truncate serialisation)
+ *       page_lock (MM)
+ *         i_lock (XFS - extent map serialisation)
  */
-STATIC int
-xfs_filemap_fault(
-	struct vm_area_struct	*vma,
-	struct vm_fault		*vmf)
-{
-	struct xfs_inode	*ip = XFS_I(vma->vm_file->f_mapping->host);
-	int			error;
-
-	trace_xfs_filemap_fault(ip);
-
-	xfs_ilock(ip, XFS_MMAPLOCK_SHARED);
-	error = filemap_fault(vma, vmf);
-	xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
-
-	return error;
-}
 
 /*
  * mmap()d file has taken write protection fault and is being made writable. We
@@ -1486,21 +1467,66 @@ xfs_filemap_page_mkwrite(
 	struct vm_area_struct	*vma,
 	struct vm_fault		*vmf)
 {
-	struct xfs_inode	*ip = XFS_I(vma->vm_file->f_mapping->host);
+	struct inode		*inode = file_inode(vma->vm_file);
 	int			ret;
 
-	trace_xfs_filemap_page_mkwrite(ip);
+	trace_xfs_filemap_page_mkwrite(XFS_I(inode));
 
-	sb_start_pagefault(VFS_I(ip)->i_sb);
+	sb_start_pagefault(inode->i_sb);
 	file_update_time(vma->vm_file);
-	xfs_ilock(ip, XFS_MMAPLOCK_SHARED);
+	xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
+
+	if (IS_DAX(inode)) {
+		ret = __dax_mkwrite(vma, vmf, xfs_get_blocks_direct,
+				    xfs_end_io_dax_write);
+	} else {
+		ret = __block_page_mkwrite(vma, vmf, xfs_get_blocks);
+		ret = block_page_mkwrite_return(ret);
+	}
+
+	xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
+	sb_end_pagefault(inode->i_sb);
+
+	return ret;
+}
+
+STATIC int
+xfs_filemap_fault(
+	struct vm_area_struct	*vma,
+	struct vm_fault		*vmf)
+{
+	struct xfs_inode	*ip = XFS_I(file_inode(vma->vm_file));
+	int			ret;
 
-	ret = __block_page_mkwrite(vma, vmf, xfs_get_blocks);
+	trace_xfs_filemap_fault(ip);
+
+	/* DAX can shortcut the normal fault path on write faults! */
+	if ((vmf->flags & FAULT_FLAG_WRITE) && IS_DAX(VFS_I(ip)))
+		return xfs_filemap_page_mkwrite(vma, vmf);
 
+	xfs_ilock(ip, XFS_MMAPLOCK_SHARED);
+	ret = filemap_fault(vma, vmf);
 	xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
-	sb_end_pagefault(VFS_I(ip)->i_sb);
 
-	return block_page_mkwrite_return(ret);
+	return ret;
+}
+
+static const struct vm_operations_struct xfs_file_vm_ops = {
+	.fault		= xfs_filemap_fault,
+	.map_pages	= filemap_map_pages,
+	.page_mkwrite	= xfs_filemap_page_mkwrite,
+};
+
+STATIC int
+xfs_file_mmap(
+	struct file	*filp,
+	struct vm_area_struct *vma)
+{
+	file_accessed(filp);
+	vma->vm_ops = &xfs_file_vm_ops;
+	if (IS_DAX(file_inode(filp)))
+		vma->vm_flags |= VM_MIXEDMAP;
+	return 0;
 }
 
 const struct file_operations xfs_file_operations = {
@@ -1531,9 +1557,3 @@ const struct file_operations xfs_dir_file_operations = {
 #endif
 	.fsync		= xfs_dir_fsync,
 };
-
-static const struct vm_operations_struct xfs_file_vm_ops = {
-	.fault		= xfs_filemap_fault,
-	.map_pages	= filemap_map_pages,
-	.page_mkwrite	= xfs_filemap_page_mkwrite,
-};