Re: [PATCH] (and bad attr2 bug) - pack xfs_sb_t for 64-bit arches

[Eric Sandeen <sandeen@xxxxxxxxxxx>]

Eric Sandeen wrote:

> Eric Sandeen wrote:
>   
> > ugh.  it's broken on x86 too, so it's not just the alignment/padding,
> >     
> > although that should be fixed for cross-arch mounts.
> >     
> > -Eric
> >     
> >     
> here's a testcase to corrupt it FWIW.
>   
>   
Ok, with expert collaboration from Russell, Barry, Tim, 
Nathan, David, et al, how about this:

For btree dirs, we need a different calculation for the space
used in di_u, to set the minimum threshold for the fork offset...

This fixes my testcase, but as Tim points out -now- we need to compact
the btree ptrs, if we return (and use) an offset < current forkoff...

whee....

-Eric


Index: linux-2.6.18/fs/xfs.orig/xfs_attr_leaf.c
===================================================================
--- linux-2.6.18.orig/fs/xfs.orig/xfs_attr_leaf.c
+++ linux-2.6.18/fs/xfs.orig/xfs_attr_leaf.c
@@ -116,6 +116,7 @@ xfs_attr_shortform_bytesfit(xfs_inode_t 
	int minforkoff;	/* lower limit on valid forkoff locations */
	int maxforkoff;	/* upper limit on valid forkoff locations */
	xfs_mount_t *mp = dp->i_mount;
+	int dsize = 0;

        offset = (XFS_LITINO(mp) - bytes) >> 3; /* rounded down */

@@ -134,8 +135,21 @@ xfs_attr_shortform_bytesfit(xfs_inode_t 
		return 0;
	}

+       switch (dp->i_d.di_format) {
+       case XFS_DINODE_FMT_LOCAL:
+       case XFS_DINODE_FMT_EXTENTS:
+               dsize = dp->i_df.if_bytes;
+               break;
+       case XFS_DINODE_FMT_BTREE:
+               dsize = XFS_BMDR_SPACE_CALC(
+                       XFS_BMAP_BROOT_NUMRECS(dp->i_df.if_broot));
+               break;
+       default:
+               /* should bail, unknown format, .... */
+       }
+
        /* data fork btree root can have at least this many key/ptr pairs */
-       minforkoff = MAX(dp->i_df.if_bytes, XFS_BMDR_SPACE_CALC(MINDBTPTRS));
+       minforkoff = MAX(dsize, XFS_BMDR_SPACE_CALC(MINDBTPTRS));
        minforkoff = roundup(minforkoff, 8) >> 3;

        /* attr fork btree root can have at least this many key/ptr pairs */