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Commit 3af49285 authored by Dave Chinner's avatar Dave Chinner Committed by Dave Chinner
Browse files

xfs: add ->pfn_mkwrite support for DAX 



->pfn_mkwrite support is needed so that when a page with allocated
backing store takes a write fault we can check that the fault has
not raced with a truncate and is pointing to a region beyond the
current end of file.

This also allows us to update the timestamp on the inode, too, which
fixes a generic/080 failure.

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 01a155e6

fs/xfs/xfs_file.c

+35 −0
Original line number Diff line number Diff line
@@ -1572,11 +1572,46 @@ xfs_filemap_pmd_fault( 
	return ret;

}



/*

 * pfn_mkwrite was originally inteneded to ensure we capture time stamp

 * updates on write faults. In reality, it's need to serialise against

 * truncate similar to page_mkwrite. Hence we open-code dax_pfn_mkwrite()

 * here and cycle the XFS_MMAPLOCK_SHARED to ensure we serialise the fault

 * barrier in place.

 */

static int

xfs_filemap_pfn_mkwrite(

	struct vm_area_struct	*vma,

	struct vm_fault		*vmf)

{



	struct inode		*inode = file_inode(vma->vm_file);

	struct xfs_inode	*ip = XFS_I(inode);

	int			ret = VM_FAULT_NOPAGE;

	loff_t			size;



	trace_xfs_filemap_pfn_mkwrite(ip);



	sb_start_pagefault(inode->i_sb);

	file_update_time(vma->vm_file);



	/* check if the faulting page hasn't raced with truncate */

	xfs_ilock(ip, XFS_MMAPLOCK_SHARED);

	size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;

	if (vmf->pgoff >= size)

		ret = VM_FAULT_SIGBUS;

	xfs_iunlock(ip, 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,

	.pfn_mkwrite	= xfs_filemap_pfn_mkwrite,

};



STATIC int

fs/xfs/xfs_trace.h

+1 −0
Original line number Diff line number Diff line
@@ -689,6 +689,7 @@ 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);

DEFINE_INODE_EVENT(xfs_filemap_pfn_mkwrite);



DECLARE_EVENT_CLASS(xfs_iref_class,

	TP_PROTO(struct xfs_inode *ip, unsigned long caller_ip),