[PATCH V2] xfsprogs: xfs_fsr: Verify bulkstat version information in qsort's cmp()

[Chandan Babu R <chandanrlinux@gmail.com>]

This commit introduces a check to verify that correct bulkstat structures are
being processed by qsort's cmp() function.

Suggested-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
V1 -> V2:
   1. Include XFS_BULKSTAT_VERSION_V1 as a possible bulkstat version
      number. 
   2. Fix coding style issue.
   
 fsr/xfs_fsr.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/fsr/xfs_fsr.c b/fsr/xfs_fsr.c
index b885395e..6cf8bfb7 100644
--- a/fsr/xfs_fsr.c
+++ b/fsr/xfs_fsr.c
@@ -582,8 +582,15 @@ fsrall_cleanup(int timeout)
 static int
 cmp(const void *s1, const void *s2)
 {
-	return( ((struct xfs_bulkstat *)s2)->bs_extents -
-	        ((struct xfs_bulkstat *)s1)->bs_extents);
+	const struct xfs_bulkstat	*bs1 = s1;
+	const struct xfs_bulkstat	*bs2 = s2;
+
+	ASSERT((bs1->bs_version == XFS_BULKSTAT_VERSION_V1 &&
+		bs2->bs_version == XFS_BULKSTAT_VERSION_V1) ||
+		(bs1->bs_version == XFS_BULKSTAT_VERSION_V5 &&
+		bs2->bs_version == XFS_BULKSTAT_VERSION_V5));
+
+	return (bs2->bs_extents - bs1->bs_extents);
 }
 
 /*
-- 
2.29.2