[PATCH] prevent panic during log recovery due to bogus operation header length

[Lachlan McIlroy <lachlan@sgi.com>]

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A problem was reported where a system panicked in log recovery due
to a corrupt log record.  The cause of the corruption is not known
but this change will at least prevent a crash for this specific
scenario.  Log recovery definitely needs some more work in this area.

Lachlan

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--- fs/xfs/xfs_log_recover.c_1.332	2007-12-12 17:14:57.000000000 +1100
+++ fs/xfs/xfs_log_recover.c	2007-12-12 17:15:42.000000000 +1100
@@ -2912,7 +2912,12 @@ xlog_recover_process_data(
 				xlog_recover_new_tid(&rhash[hash], tid,
 					be64_to_cpu(rhead->h_lsn));
 		} else {
-			ASSERT(dp + be32_to_cpu(ohead->oh_len) <= lp);
+			if (dp + be32_to_cpu(ohead->oh_len) > lp) {
+				xlog_warn(
+			"XFS: xlog_recover_process_data: bad length");
+				ASSERT(0);
+				return (XFS_ERROR(EIO));
+			}
 			flags = ohead->oh_flags & ~XLOG_END_TRANS;
 			if (flags & XLOG_WAS_CONT_TRANS)
 				flags &= ~XLOG_CONTINUE_TRANS;