Merge tag 'xfs-for-linus-4.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

Pull xfs fixes from Dave Chinner:
 "There are a couple of recently found, long standing remote attribute
  corruption fixes caused by log recovery getting confused after a
  crash, and the new DAX code in XFS (merged in 4.2-rc1) needs to
  actually use the DAX fault path on read faults.

  Summary:

   - remote attribute log recovery corruption fixes

   - DAX page faults need to use direct mappings, not a page cache
     mapping"

* tag 'xfs-for-linus-4.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
  xfs: remote attributes need to be considered data
  xfs: remote attribute headers contain an invalid LSN
  xfs: call dax_fault on read page faults for DAX

1 files changed, 15 insertions, 6 deletions

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index f0e8249722d4..db4acc1c3e73 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1514,18 +1514,27 @@ xfs_filemap_fault(
 	struct vm_area_struct	*vma,
 	struct vm_fault		*vmf)
 {
-	struct xfs_inode	*ip = XFS_I(file_inode(vma->vm_file));
+	struct inode		*inode = file_inode(vma->vm_file);
 	int			ret;
 
-	trace_xfs_filemap_fault(ip);
+	trace_xfs_filemap_fault(XFS_I(inode));
 
 	/* DAX can shortcut the normal fault path on write faults! */
-	if ((vmf->flags & FAULT_FLAG_WRITE) && IS_DAX(VFS_I(ip)))
+	if ((vmf->flags & FAULT_FLAG_WRITE) && IS_DAX(inode))
 		return xfs_filemap_page_mkwrite(vma, vmf);
 
-	xfs_ilock(ip, XFS_MMAPLOCK_SHARED);
-	ret = filemap_fault(vma, vmf);
-	xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
+	xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
+	if (IS_DAX(inode)) {
+		/*
+		 * we do not want to trigger unwritten extent conversion on read
+		 * faults - that is unnecessary overhead and would also require
+		 * changes to xfs_get_blocks_direct() to map unwritten extent
+		 * ioend for conversion on read-only mappings.
+		 */
+		ret = __dax_fault(vma, vmf, xfs_get_blocks_direct, NULL);
+	} else
+		ret = filemap_fault(vma, vmf);
+	xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
 
 	return ret;
 }