NFS: make sure open context mode have FMODE_EXEC when file open for exec

Because file f_mode never have FMODE_EXEC, open context mode won't get
FMODE_EXEC from file f_mode. Open context mode only care about FMODE_READ/
FMODE_WRITE/FMODE_EXEC, and all info about open context mode can be convert
from file f_flags, so convert file f_flags to open context mode by
flags_to_mode().

Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Author: ChenXiaoSong

fs/nfs/inode.c

@@ -1168,7 +1168,8 @@ int nfs_open(struct inode *inode, struct file *filp)
 {
 	struct nfs_open_context *ctx;
 
-	ctx = alloc_nfs_open_context(file_dentry(filp), filp->f_mode, filp);
+	ctx = alloc_nfs_open_context(file_dentry(filp),
+				     flags_to_mode(filp->f_flags), filp);
 	if (IS_ERR(ctx))
 		return PTR_ERR(ctx);
 	nfs_file_set_open_context(filp, ctx);

fs/nfs/nfs4file.c

@@ -32,7 +32,6 @@ nfs4_file_open(struct inode *inode, struct file *filp)
 	struct dentry *parent = NULL;
 	struct inode *dir;
 	unsigned openflags = filp->f_flags;
-	fmode_t f_mode;
 	struct iattr attr;
 	int err;
 
@@ -51,17 +50,14 @@ nfs4_file_open(struct inode *inode, struct file *filp)
 	if (err)
 		return err;
 
-	f_mode = filp->f_mode;
-	if ((openflags & O_ACCMODE) == 3)
-		f_mode |= flags_to_mode(openflags);
-
 	/* We can't create new files here */
 	openflags &= ~(O_CREAT|O_EXCL);
 
 	parent = dget_parent(dentry);
 	dir = d_inode(parent);
 
-	ctx = alloc_nfs_open_context(file_dentry(filp), f_mode, filp);
+	ctx = alloc_nfs_open_context(file_dentry(filp),
+				     flags_to_mode(openflags), filp);
 	err = PTR_ERR(ctx);
 	if (IS_ERR(ctx))
 		goto out;
@@ -366,8 +362,8 @@ static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
 		goto out_free_name;
 	}
 
-	ctx = alloc_nfs_open_context(filep->f_path.dentry, filep->f_mode,
-					filep);
+	ctx = alloc_nfs_open_context(filep->f_path.dentry,
+				     flags_to_mode(filep->f_flags), filep);
 	if (IS_ERR(ctx)) {
 		res = ERR_CAST(ctx);
 		goto out_filep;