[PATCH v2 4/4] nfsd: add appropriate __force directives to filehandle generation code

[Jeff Layton <jlayton@primarydata.com>]

The filehandle structs all use host-endian values, but will sometimes
stuff big-endian values into those fields. This is OK since these
values are opaque to the client, but it confuses sparse. Add __force to
make it clear that we are doing this intentionally.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
---
 fs/nfsd/nfsfh.c |  9 ++++++++-
 fs/nfsd/nfsfh.h | 15 +++++++++++----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index ec8393418154..7e5b2d993372 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -162,7 +162,14 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 			/* deprecated, convert to type 3 */
 			len = key_len(FSID_ENCODE_DEV)/4;
 			fh->fh_fsid_type = FSID_ENCODE_DEV;
-			fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
+			/*
+			 * struct knfsd_fh uses host-endian fields, which are
+			 * sometimes used to hold net-endian values. This
+			 * confuses sparse, so we must use __force here to
+			 * keep it from complaining.
+			 */
+			fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl((__force __be32)fh->fh_fsid[0]),
+							ntohl((__force __be32)fh->fh_fsid[1])));
 			fh->fh_fsid[1] = fh->fh_fsid[2];
 		}
 		data_left -= len;
diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h
index 2e89e70ac15c..08236d70c667 100644
--- a/fs/nfsd/nfsfh.h
+++ b/fs/nfsd/nfsfh.h
@@ -73,8 +73,15 @@ enum fsid_source {
 extern enum fsid_source fsid_source(struct svc_fh *fhp);
 
 
-/* This might look a little large to "inline" but in all calls except
+/*
+ * This might look a little large to "inline" but in all calls except
  * one, 'vers' is constant so moste of the function disappears.
+ *
+ * In some cases the values are considered to be host endian and in
+ * others, net endian. fsidv is always considered to be u32 as the
+ * callers don't know which it will be. So we must use __force to keep
+ * sparse from complaining. Since these values are opaque to the
+ * client, that shouldn't be a problem.
  */
 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
 			   u32 fsid, unsigned char *uuid)
@@ -82,7 +89,7 @@ static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
 	u32 *up;
 	switch(vers) {
 	case FSID_DEV:
-		fsidv[0] = htonl((MAJOR(dev)<<16) |
+		fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
 				 MINOR(dev));
 		fsidv[1] = ino_t_to_u32(ino);
 		break;
@@ -90,8 +97,8 @@ static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
 		fsidv[0] = fsid;
 		break;
 	case FSID_MAJOR_MINOR:
-		fsidv[0] = htonl(MAJOR(dev));
-		fsidv[1] = htonl(MINOR(dev));
+		fsidv[0] = (__force __u32)htonl(MAJOR(dev));
+		fsidv[1] = (__force __u32)htonl(MINOR(dev));
 		fsidv[2] = ino_t_to_u32(ino);
 		break;
 
-- 
1.9.3