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xfs: kill unnecessary firstused overflow check on attr3 leaf removal 

xfs_attr3_leaf_remove() removes an attribute from an attr leaf block. If
the attribute nameval data happens to be at the start of the nameval
region, a new start offset (firstused) for the region is calculated
(since the region grows from the tail of the block to the start). Once
the new firstused is calculated, it is checked for zero in an apparent
overflow check.

Now that the in-core firstused is 32-bit, overflow is not possible and
this check can be removed. Since the purpose for this check is not
documented and appears to exist since the port to Linux, be conservative
and replace it with an assert.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Brian Foster 2015-04-13 11:27:59 +10:00 committed by Dave Chinner
parent e87021a2bc
commit 66db810496
1 changed files with 1 additions and 2 deletions
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3
fs/xfs/libxfs/xfs_attr_leaf.c
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@ -1996,8 +1996,7 @@ xfs_attr3_leaf_remove(
tmp = be16_to_cpu(entry->nameidx);
}
ichdr.firstused = tmp;
if (!ichdr.firstused)
ichdr.firstused = tmp - XFS_ATTR_LEAF_NAME_ALIGN;
ASSERT(ichdr.firstused != 0);
} else {
ichdr.holes = 1; /* mark as needing compaction */
}