Commit 13ad4fe3 authored by Dave Chinner's avatar Dave Chinner Committed by Dave Chinner
Browse files

xfs: xfs_filemap_pmd_fault treats read faults as write faults 



The code initially committed didn't have the same checks for write
faults as the dax_pmd_fault code and hence treats all faults as
write faults. We can get read faults through this path because they
is no pmd_mkwrite path for write faults similar to the normal page
fault path. Hence we need to ensure that we only do c/mtime updates
on write faults, and freeze protection is unnecessary for read
faults.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent 3af49285

fs/xfs/xfs_file.c

+16 −4
Original line number Diff line number Diff line
@@ -1477,7 +1477,7 @@ xfs_file_llseek( 
 *

 * mmap_sem (MM)

 *   sb_start_pagefault(vfs, freeze)

 *     i_mmap_lock (XFS - truncate serialisation)

 *     i_mmaplock (XFS - truncate serialisation)

 *       page_lock (MM)

 *         i_lock (XFS - extent map serialisation)

 */
@@ -1545,6 +1545,13 @@ xfs_filemap_fault( 
	return ret;

}



/*

 * Similar to xfs_filemap_fault(), the DAX fault path can call into here on

 * both read and write faults. Hence we need to handle both cases. There is no

 * ->pmd_mkwrite callout for huge pages, so we have a single function here to

 * handle both cases here. @flags carries the information on the type of fault

 * occuring.

 */

STATIC int

xfs_filemap_pmd_fault(

	struct vm_area_struct	*vma,
@@ -1561,12 +1568,17 @@ xfs_filemap_pmd_fault( 


	trace_xfs_filemap_pmd_fault(ip);



	if (flags & FAULT_FLAG_WRITE) {

		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_dax_fault,

			      NULL);

	xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);



	if (flags & FAULT_FLAG_WRITE)

		sb_end_pagefault(inode->i_sb);



	return ret;

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