NFSv4.1: Fix wraparound issues in pnfs_seqid_is_newer()
Subtraction of signed integers does not have well defined wraparound
semantics in the C99 standard. In order to be wraparound-safe, we
have to use unsigned subtraction, and then cast the result.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 4755858..6e67ada 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -662,7 +662,7 @@
*/
static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
{
- return (s32)s1 - (s32)s2 > 0;
+ return (s32)(s1 - s2) > 0;
}
/* update lo->plh_stateid with new if is more recent */