NFSv4.2: Update mode bits after ALLOCATE and DEALLOCATE

The fallocate call invalidates suid and sgid bits as part of normal
operation. We need to mark the mode bits as invalid when using fallocate
with an suid so these will be updated the next time the user looks at them.

This fixes xfstests generic/683 and generic/684.

Reported-by: Yue Cui <cuiyue-fnst@fujitsu.com>
Fixes: 913eca1aea ("NFS: Fallocate should use the nfs4_fattr_bitmap")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/internal.h

@@ -604,6 +604,31 @@ static inline gfp_t nfs_io_gfp_mask(void)
 	return GFP_KERNEL;
 }
 
+/*
+ * Special version of should_remove_suid() that ignores capabilities.
+ */
+static inline int nfs_should_remove_suid(const struct inode *inode)
+{
+	umode_t mode = inode->i_mode;
+	int kill = 0;
+
+	/* suid always must be killed */
+	if (unlikely(mode & S_ISUID))
+		kill = ATTR_KILL_SUID;
+
+	/*
+	 * sgid without any exec bits is just a mandatory locking mark; leave
+	 * it alone.  If some exec bits are set, it's a real sgid; kill it.
+	 */
+	if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
+		kill |= ATTR_KILL_SGID;
+
+	if (unlikely(kill && S_ISREG(mode)))
+		return kill;
+
+	return 0;
+}
+
 /* unlink.c */
 extern struct rpc_task *
 nfs_async_rename(struct inode *old_dir, struct inode *new_dir,

fs/nfs/nfs42proc.c

@@ -78,10 +78,15 @@ static int _nfs42_proc_fallocate(struct rpc_message *msg, struct file *filep,
 
 	status = nfs4_call_sync(server->client, server, msg,
 				&args.seq_args, &res.seq_res, 0);
-	if (status == 0)
+	if (status == 0) {
+		if (nfs_should_remove_suid(inode)) {
+			spin_lock(&inode->i_lock);
+			nfs_set_cache_invalid(inode, NFS_INO_INVALID_MODE);
+			spin_unlock(&inode->i_lock);
+		}
 		status = nfs_post_op_update_inode_force_wcc(inode,
 							    res.falloc_fattr);
-
+	}
 	if (msg->rpc_proc == &nfs4_procedures[NFSPROC4_CLNT_ALLOCATE])
 		trace_nfs4_fallocate(inode, &args, status);
 	else

fs/nfs/write.c

@@ -1496,31 +1496,6 @@ void nfs_commit_prepare(struct rpc_task *task, void *calldata)
 	NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
 }
 
-/*
- * Special version of should_remove_suid() that ignores capabilities.
- */
-static int nfs_should_remove_suid(const struct inode *inode)
-{
-	umode_t mode = inode->i_mode;
-	int kill = 0;
-
-	/* suid always must be killed */
-	if (unlikely(mode & S_ISUID))
-		kill = ATTR_KILL_SUID;
-
-	/*
-	 * sgid without any exec bits is just a mandatory locking mark; leave
-	 * it alone.  If some exec bits are set, it's a real sgid; kill it.
-	 */
-	if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
-		kill |= ATTR_KILL_SGID;
-
-	if (unlikely(kill && S_ISREG(mode)))
-		return kill;
-
-	return 0;
-}
-
 static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
 		struct nfs_fattr *fattr)
 {