[003/119] xfs: check offsets of variable length structures
diff mbox

Message ID 146612629195.12839.14090954204243398929.stgit@birch.djwong.org
State New
Headers show

Commit Message

Darrick J. Wong June 17, 2016, 1:18 a.m. UTC
Some of the directory/attr structures contain variable-length objects,
so the enclosing structure doesn't have a meaningful fixed size at
compile time.  We can check the offsets of the members before the
variable-length member, so do those.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_ondisk.h |   25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)



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Comments

Christoph Hellwig June 17, 2016, 11:33 a.m. UTC | #1
On Thu, Jun 16, 2016 at 06:18:12PM -0700, Darrick J. Wong wrote:
> Some of the directory/attr structures contain variable-length objects,
> so the enclosing structure doesn't have a meaningful fixed size at
> compile time.  We can check the offsets of the members before the
> variable-length member, so do those.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Looks fine, and should go in independently of the rmap work:

Reviewed-by: Christoph Hellwig <hch@lst.de>
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Brian Foster June 17, 2016, 5:34 p.m. UTC | #2
On Thu, Jun 16, 2016 at 06:18:12PM -0700, Darrick J. Wong wrote:
> Some of the directory/attr structures contain variable-length objects,
> so the enclosing structure doesn't have a meaningful fixed size at
> compile time.  We can check the offsets of the members before the
> variable-length member, so do those.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---

I'm missing why this is necessary. Is the intent still to catch
alignment and/or padding issues? If so, isn't the size check sufficient,
regardless of trailing variable size fields?

Perhaps the goal here is to reduce the scope of checking from where it
isn't needed..? For example, xfs_dir2_data_unused_t looks like it has a
field where the offset in the structure is irrelevant, so that's a
possible false positive if that changes down the road. On the flip side,
that doesn't appear to be the case for other structures such as
xfs_attr_leaf_name_[local|remote]_t.

Brian

>  fs/xfs/xfs_ondisk.h |   25 +++++++++++++++++++++++--
>  1 file changed, 23 insertions(+), 2 deletions(-)
> 
> 
> diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> index 184c44e..0272301 100644
> --- a/fs/xfs/xfs_ondisk.h
> +++ b/fs/xfs/xfs_ondisk.h
> @@ -22,6 +22,11 @@
>  	BUILD_BUG_ON_MSG(sizeof(structname) != (size), "XFS: sizeof(" \
>  		#structname ") is wrong, expected " #size)
>  
> +#define XFS_CHECK_OFFSET(structname, member, off) \
> +	BUILD_BUG_ON_MSG(offsetof(structname, member) != (off), \
> +		"XFS: offsetof(" #structname ", " #member ") is wrong, " \
> +		"expected " #off)
> +
>  static inline void __init
>  xfs_check_ondisk_structs(void)
>  {
> @@ -75,15 +80,28 @@ xfs_check_ondisk_structs(void)
>  	XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_name_remote_t,	12);
>  	 */
>  
> +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, valuelen,	0);
> +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, namelen,	2);
> +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, nameval,	3);
> +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valueblk,	0);
> +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valuelen,	4);
> +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, namelen,	8);
> +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, name,	9);
>  	XFS_CHECK_STRUCT_SIZE(xfs_attr_leafblock_t,		40);
> -	XFS_CHECK_STRUCT_SIZE(xfs_attr_shortform_t,		8);
> +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.totsize,	0);
> +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.count,	2);
> +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].namelen,	4);
> +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].valuelen, 5);
> +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].flags,	6);
> +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].nameval,	7);
>  	XFS_CHECK_STRUCT_SIZE(xfs_da_blkinfo_t,			12);
>  	XFS_CHECK_STRUCT_SIZE(xfs_da_intnode_t,			16);
>  	XFS_CHECK_STRUCT_SIZE(xfs_da_node_entry_t,		8);
>  	XFS_CHECK_STRUCT_SIZE(xfs_da_node_hdr_t,		16);
>  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_free_t,		4);
>  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_hdr_t,		16);
> -	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_unused_t,		6);
> +	XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, freetag,	0);
> +	XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, length,	2);
>  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_hdr_t,		16);
>  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_t,			16);
>  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_ino4_t,			4);
> @@ -94,6 +112,9 @@ xfs_check_ondisk_structs(void)
>  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_t,			16);
>  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_tail_t,		4);
>  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_entry_t,		3);
> +	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, namelen,		0);
> +	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, offset,		1);
> +	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, name,		3);
>  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_hdr_t,		10);
>  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_off_t,		2);
>  
> 
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs
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Darrick J. Wong June 18, 2016, 6:01 p.m. UTC | #3
On Fri, Jun 17, 2016 at 01:34:27PM -0400, Brian Foster wrote:
> On Thu, Jun 16, 2016 at 06:18:12PM -0700, Darrick J. Wong wrote:
> > Some of the directory/attr structures contain variable-length objects,
> > so the enclosing structure doesn't have a meaningful fixed size at
> > compile time.  We can check the offsets of the members before the
> > variable-length member, so do those.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> 
> I'm missing why this is necessary. Is the intent still to catch
> alignment and/or padding issues? If so, isn't the size check sufficient,
> regardless of trailing variable size fields?
> 
> Perhaps the goal here is to reduce the scope of checking from where it
> isn't needed..? For example, xfs_dir2_data_unused_t looks like it has a
> field where the offset in the structure is irrelevant, so that's a
> possible false positive if that changes down the road. On the flip side,
> that doesn't appear to be the case for other structures such as
> xfs_attr_leaf_name_[local|remote]_t.

ISTR making this change to work around behavioral variances in how
much padding gcc adds to structures across its various targets.  The
macros that go along with the variable sized structures work fine,
but testing the sizeof() doesn't work reliably.

--D

> 
> Brian
> 
> >  fs/xfs/xfs_ondisk.h |   25 +++++++++++++++++++++++--
> >  1 file changed, 23 insertions(+), 2 deletions(-)
> > 
> > 
> > diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> > index 184c44e..0272301 100644
> > --- a/fs/xfs/xfs_ondisk.h
> > +++ b/fs/xfs/xfs_ondisk.h
> > @@ -22,6 +22,11 @@
> >  	BUILD_BUG_ON_MSG(sizeof(structname) != (size), "XFS: sizeof(" \
> >  		#structname ") is wrong, expected " #size)
> >  
> > +#define XFS_CHECK_OFFSET(structname, member, off) \
> > +	BUILD_BUG_ON_MSG(offsetof(structname, member) != (off), \
> > +		"XFS: offsetof(" #structname ", " #member ") is wrong, " \
> > +		"expected " #off)
> > +
> >  static inline void __init
> >  xfs_check_ondisk_structs(void)
> >  {
> > @@ -75,15 +80,28 @@ xfs_check_ondisk_structs(void)
> >  	XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_name_remote_t,	12);
> >  	 */
> >  
> > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, valuelen,	0);
> > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, namelen,	2);
> > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, nameval,	3);
> > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valueblk,	0);
> > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valuelen,	4);
> > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, namelen,	8);
> > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, name,	9);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_attr_leafblock_t,		40);
> > -	XFS_CHECK_STRUCT_SIZE(xfs_attr_shortform_t,		8);
> > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.totsize,	0);
> > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.count,	2);
> > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].namelen,	4);
> > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].valuelen, 5);
> > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].flags,	6);
> > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].nameval,	7);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_da_blkinfo_t,			12);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_da_intnode_t,			16);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_da_node_entry_t,		8);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_da_node_hdr_t,		16);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_free_t,		4);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_hdr_t,		16);
> > -	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_unused_t,		6);
> > +	XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, freetag,	0);
> > +	XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, length,	2);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_hdr_t,		16);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_t,			16);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_ino4_t,			4);
> > @@ -94,6 +112,9 @@ xfs_check_ondisk_structs(void)
> >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_t,			16);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_tail_t,		4);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_entry_t,		3);
> > +	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, namelen,		0);
> > +	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, offset,		1);
> > +	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, name,		3);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_hdr_t,		10);
> >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_off_t,		2);
> >  
> > 
> > _______________________________________________
> > xfs mailing list
> > xfs@oss.sgi.com
> > http://oss.sgi.com/mailman/listinfo/xfs
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Brian Foster June 20, 2016, 12:38 p.m. UTC | #4
On Sat, Jun 18, 2016 at 11:01:33AM -0700, Darrick J. Wong wrote:
> On Fri, Jun 17, 2016 at 01:34:27PM -0400, Brian Foster wrote:
> > On Thu, Jun 16, 2016 at 06:18:12PM -0700, Darrick J. Wong wrote:
> > > Some of the directory/attr structures contain variable-length objects,
> > > so the enclosing structure doesn't have a meaningful fixed size at
> > > compile time.  We can check the offsets of the members before the
> > > variable-length member, so do those.
> > > 
> > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > > ---
> > 
> > I'm missing why this is necessary. Is the intent still to catch
> > alignment and/or padding issues? If so, isn't the size check sufficient,
> > regardless of trailing variable size fields?
> > 
> > Perhaps the goal here is to reduce the scope of checking from where it
> > isn't needed..? For example, xfs_dir2_data_unused_t looks like it has a
> > field where the offset in the structure is irrelevant, so that's a
> > possible false positive if that changes down the road. On the flip side,
> > that doesn't appear to be the case for other structures such as
> > xfs_attr_leaf_name_[local|remote]_t.
> 
> ISTR making this change to work around behavioral variances in how
> much padding gcc adds to structures across its various targets.  The
> macros that go along with the variable sized structures work fine,
> but testing the sizeof() doesn't work reliably.
> 

Ok, I take that to mean that we may or may not have padding in some of
the variable structures depending on architecture (and we really only
care about certain fields in those structures). Fair enough, thanks!

Brian

> --D
> 
> > 
> > Brian
> > 
> > >  fs/xfs/xfs_ondisk.h |   25 +++++++++++++++++++++++--
> > >  1 file changed, 23 insertions(+), 2 deletions(-)
> > > 
> > > 
> > > diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> > > index 184c44e..0272301 100644
> > > --- a/fs/xfs/xfs_ondisk.h
> > > +++ b/fs/xfs/xfs_ondisk.h
> > > @@ -22,6 +22,11 @@
> > >  	BUILD_BUG_ON_MSG(sizeof(structname) != (size), "XFS: sizeof(" \
> > >  		#structname ") is wrong, expected " #size)
> > >  
> > > +#define XFS_CHECK_OFFSET(structname, member, off) \
> > > +	BUILD_BUG_ON_MSG(offsetof(structname, member) != (off), \
> > > +		"XFS: offsetof(" #structname ", " #member ") is wrong, " \
> > > +		"expected " #off)
> > > +
> > >  static inline void __init
> > >  xfs_check_ondisk_structs(void)
> > >  {
> > > @@ -75,15 +80,28 @@ xfs_check_ondisk_structs(void)
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_name_remote_t,	12);
> > >  	 */
> > >  
> > > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, valuelen,	0);
> > > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, namelen,	2);
> > > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, nameval,	3);
> > > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valueblk,	0);
> > > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valuelen,	4);
> > > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, namelen,	8);
> > > +	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, name,	9);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_attr_leafblock_t,		40);
> > > -	XFS_CHECK_STRUCT_SIZE(xfs_attr_shortform_t,		8);
> > > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.totsize,	0);
> > > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.count,	2);
> > > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].namelen,	4);
> > > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].valuelen, 5);
> > > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].flags,	6);
> > > +	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].nameval,	7);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_da_blkinfo_t,			12);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_da_intnode_t,			16);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_da_node_entry_t,		8);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_da_node_hdr_t,		16);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_free_t,		4);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_hdr_t,		16);
> > > -	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_unused_t,		6);
> > > +	XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, freetag,	0);
> > > +	XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, length,	2);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_hdr_t,		16);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_t,			16);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_ino4_t,			4);
> > > @@ -94,6 +112,9 @@ xfs_check_ondisk_structs(void)
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_t,			16);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_tail_t,		4);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_entry_t,		3);
> > > +	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, namelen,		0);
> > > +	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, offset,		1);
> > > +	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, name,		3);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_hdr_t,		10);
> > >  	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_off_t,		2);
> > >  
> > > 
> > > _______________________________________________
> > > xfs mailing list
> > > xfs@oss.sgi.com
> > > http://oss.sgi.com/mailman/listinfo/xfs
> 
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs
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Patch
diff mbox

diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index 184c44e..0272301 100644
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -22,6 +22,11 @@ 
 	BUILD_BUG_ON_MSG(sizeof(structname) != (size), "XFS: sizeof(" \
 		#structname ") is wrong, expected " #size)
 
+#define XFS_CHECK_OFFSET(structname, member, off) \
+	BUILD_BUG_ON_MSG(offsetof(structname, member) != (off), \
+		"XFS: offsetof(" #structname ", " #member ") is wrong, " \
+		"expected " #off)
+
 static inline void __init
 xfs_check_ondisk_structs(void)
 {
@@ -75,15 +80,28 @@  xfs_check_ondisk_structs(void)
 	XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_name_remote_t,	12);
 	 */
 
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, valuelen,	0);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, namelen,	2);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, nameval,	3);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valueblk,	0);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valuelen,	4);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, namelen,	8);
+	XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, name,	9);
 	XFS_CHECK_STRUCT_SIZE(xfs_attr_leafblock_t,		40);
-	XFS_CHECK_STRUCT_SIZE(xfs_attr_shortform_t,		8);
+	XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.totsize,	0);
+	XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.count,	2);
+	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].namelen,	4);
+	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].valuelen, 5);
+	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].flags,	6);
+	XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].nameval,	7);
 	XFS_CHECK_STRUCT_SIZE(xfs_da_blkinfo_t,			12);
 	XFS_CHECK_STRUCT_SIZE(xfs_da_intnode_t,			16);
 	XFS_CHECK_STRUCT_SIZE(xfs_da_node_entry_t,		8);
 	XFS_CHECK_STRUCT_SIZE(xfs_da_node_hdr_t,		16);
 	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_free_t,		4);
 	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_hdr_t,		16);
-	XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_unused_t,		6);
+	XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, freetag,	0);
+	XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, length,	2);
 	XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_hdr_t,		16);
 	XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_t,			16);
 	XFS_CHECK_STRUCT_SIZE(xfs_dir2_ino4_t,			4);
@@ -94,6 +112,9 @@  xfs_check_ondisk_structs(void)
 	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_t,			16);
 	XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_tail_t,		4);
 	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_entry_t,		3);
+	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, namelen,		0);
+	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, offset,		1);
+	XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, name,		3);
 	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_hdr_t,		10);
 	XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_off_t,		2);