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

[Eric Sandeen <sandeen@sandeen.net>]

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 */